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Science for South Africa

ISSN ISSN 1729-830X 1729-830X

Volume Volume 3 3 •• Number Number 3 2 •• 2007 2007 R25 R20

A cAacd y y ooff SScci ieen off SSoouut thhA A f irci ac a ae dm em nc ce e o fr


The Department of Science and Technology, with the support of Sasol and BMW, present the world’s foremost exhibition of the greatest scientific discoveries made in our time.


Cover stories

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Tracking elephants: the path to the satellite era Steve and Michelle Henley Remarkable ways of following animals in the wild

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Mosaic of satellite data

Contents VOLUME 3 • NUMBER 3 • 2007

Corné Eloff New nationwide hi-res views of South Africa’s land surface

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Regulars Fact files Finding out more about elephants (p.8) • Facts about termites (p. 25)

A KhoeSan survival story Alan G. Morris

Science news

How a group of people has evolved and adapted over time

Revolutionary wireless connections; Helping the blind to see (p. 15) • South Africa’s new HIV/AIDS plan; More IPCC reports on climate change (p. 21) • Road safety: Don’t phone when you drive; Young people at risk (p. 35) • Discovery of a new Earth-like extrasolar planet (p. 40)

Farming fungi – termites show the way

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Duur Aanen and Wilhelm de Beer Termites cultivate mushrooms in air-conditioned nests!

Features

Your QUESTions answered How should we deal with elephant numbers? – Rudi van Aarde, Tim Jackson, and Graham Kerley

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Measuring up

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Books Chameleons of Southern Africa • and other title

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The S&T tourist Science Tunnel travels ArchiMeDes

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Keep watching out for great exhibitions

Special Fact File – Comets South African Astronomical Observatory

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Careers Work in aviation

Snapshots of Solar System wanderers

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Letters to QUEST Bees and trees • Invitation

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Crossword puzzle

Viewpoint Putting it all together – integrating technologies for business applications

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Diary of events

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ASSAf news Water, water everywhere? Unfortunately not!

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Subscription form

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Back page science • Mathematical puzzle

Bokkie Fourie Remote sensing comes of age

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Science for South AfricA

ISSN ISSN 1729-830X 1729-830X

Volume Volume 3 3 •• Number Number 3 2 •• 2007 2007 r25 r20

A cAAcd y y ooff SSccI IeeN off SSoouut thhA A f IrcI Ac A Ae dm em Nc ce e o fr

A herd of elephants on its way to drink in Etosha National Park, Namibia. Photograph: Rudi J. van Aarde

SCIENCE FOR SOUTH AFRICA

ISSN 1729-830X

Editor Elisabeth Lickindorf Editorial Board Wieland Gevers (University of Cape Town) (Chair) Graham Baker (South African Journal of Science) Phil Charles (SAAO) Anusuya Chinsamy-Turan (University of Cape Town) George Ellis (University of Cape Town) Jonathan Jansen (University of Pretoria) Correspondence and The Editor enquiries PO Box 1011, Melville 2109 Tel./fax: (011) 673 3683 e-mail: editor.quest@iafrica.com (For more information visit www.questsciencemagazine.co.za) Advertising enquiries Barbara Spence Avenue Advertising PO Box 71308 Bryanston 2021 Tel.: (011) 463 7940 Fax: (011) 463 7939 Cell: 082 881 3454 e-mail: barbara@avenue.co.za Subscription enquiries Meg Kemp and back issues Tel./Fax: (012) 804 7637 or (011) 673 3683 e-mail: quest.subscription@gmail.com or editor.quest@iafrica.com Copyright © 2007 Academy of Science of South Africa

Revolutionary Science N

ever before have there been so many scientific breakthroughs – all because of the technological advances that are revolutionizing the way science is conducted and that spill over into the way we live and work. This issue of QUEST is full of links and investigative pathways that turn cutting-edge technologies into tools for scientific enquiry, and that create mechanisms which constantly transform familiar everyday experiences. Advances happen and spread so quickly that we are hardly aware of how revolutionary they are. Satellites and the benefits they bring run through many of our articles. South Africa has collected data from spacecraft over many years – we see the results on daily weather maps and we use space communication whenever we use a cellphone. But the datasets become ever more sophisticated. Now the country is celebrating its new three-year access to detailed data from the SPOT satellite constellation, giving opportunities to understand our national land surface better than ever and to use the data to improve everyone’s quality of life – by delivering better services to urban settlements, for instance, and looking after our natural resources (p. 13). Elephant densities have been much in the news. With help from satellites, researchers are discovering in unprecedented detail just how these animals move through game reserves. Once analysed, the information will tell decision-makers what they can do to help elephants and people to co-exist, in an environment that remains healthy and friendly to all (p. 3). The economy too is reaping rewards from technological revolution. South African businesses benefit their efficiency and their bottom lines by combining different computer and communication processes to achieve specific goals – such as irrigating crops by remote control, or ‘following’ a truck on its journey by road from A to B (p. 32). The country has, in fact, almost without noticing, joined a global wireless-communication revolution – we recognize it, for instance, every time a cashier in a shop removes an electronic tag from an item we’ve just paid for (p. 15). Having marvelled at the heavenly spectacle of the Great Comet of 2007 last January, we can look with wonderment at the technological sophistication that has allowed space missions to gather information about the properties of these magnificent natural phenomena (p. 30). The sophistication of DNA analysis has helped researchers delving into pre-history to discover more about how southern Africa’s KhoeSan ancestors evolved and migrated over the past 100 000 years (p. 16). And, in a different field of study altogether, DNA has also shown how termites originally from rain-forest regions adapted and survived migration to the savannas by learning to design air-conditioned nests in which to cultivate mushrooms for food (p. 22). The moral of these stories is that science depends on technology for its advances – and vice versa.

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Join QUEST’s knowledge-sharing activities Write letters for our regular Letters column – e-mail or fax your letter to The Editor. (Write QUEST LETTER in the subject line.) ■ Ask science and technology (S&T) questions for specialist members of the Academy of Science to answer in our regular Questions and Answers column – e-mail or fax your questions to The Editor. (Write QUEST QUESTION in the subject line.) ■ Inform readers in our regular Diary of Events column about science and technology events that you may be organizing. (Write QUEST DIARY clearly on your e-mail or fax and provide full and accurate details.) ■ Contribute if you are a specialist with research to report. Ask the Editor for a copy of QUEST’s Call for Contributions (or find it at www.questsciencemagazine.co.za), and make arrangements to tell us your story. To contact the Editor, send an e-mail to: editor.quest@iafrica.com or fax your communication to (011) 673 3683. Please give your full name and contact details. ■


Tracking elephants the path to the satellite era Steve and Michelle Henley explain the remarkable developments that have enabled us to follow animals in the wild, from the practices of hunter-gatherers to the sophistications of space technology.

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leapfrog the process of following an animal and go directly to the place he believes the animal was, is, or soon will be. This method has been referred to as ‘speculative’ tracking and, once mastered, is a more efficient way of putting your self in the same place at the same time as your intended prey. This ability to identify signs, interpret them, and use the information to make a prediction which you then test, has been described as humankind’s earliest attempts at hypothetico– deductive reasoning, and, as such, is the basis for scientific endeavour. Ways to follow wildlife Tracking by means of spoor and sign is still used by wildlife biologists to gather data. Identifying individual animals correctly, however, and interpreting their behaviour reliably, depend typically on subjective evaluation of the available clues – these are difficult skills to master.

Above: Animals interacting with their environment leave signs of their presence. Correctly interpreted, these can provide useful information on habitat selection and behaviour. All pictures are copyright Steve and Michelle Henley

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racking wildlife is an activity probably as old as mankind itself. For the huntergatherer, living in a world where animals are potentially life threatening but also a source of protein, the ability to determine their movements would have direct survival value. Being able to identify an animal accurately from the signs it leaves behind gives a hunter the means to determine the nature of their relationship – who is the predator and who is the prey? If the animal is potential prey, tracking it by physically following the sequence of signs it leaves behind (such as spoor and broken grass-stems) improves the chances of harvesting protein. This process is called ‘systematic’ tracking. Taking it a step further, the hunter may observe the signs, interpret the behaviour and motivation behind them, and predict the status of the animal and where it will be under current environmental conditions. In this way, he can

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Tracking spoor is not always appropriate for empirical scientific research, so it tends to be practised in areas where the tracking is relatively straightforward and value judgements can be kept to a minimum, such as in the dry, dusty regions of the Kalahari. Marking. A more reliable method requires marking animals so that each is uniquely identifiable. Ear tags, coloured neck bands, branding, toe clipping, and leg bands were among the techniques widely used in the past. Bird-ringing (or, fitting numbered metal bands to the legs of birds) is still common. These methods depend on the capture of animals so as to mark them, then recapturing the live animals at a later stage, or recovering marked carcasses that provide data on movements, habitat selection, and mortality patterns. Although marking an animal is relatively inexpensive, the recovery rate of marked individuals is typically quite low. For example, less than 1% of perching songbirds fitted with bands in America are recovered. Furthermore, the probability of finding the animals again depends on having people in the right areas: no bands are recovered where nobody visits. The method is not without anthropogenic bias, which must be borne in mind when these data are analysed and interpreted. A variation on these ‘mark and recapture’ methods is the use of naturally occurring variation in animal patterns. Scientists have used nicks and tears in the ears of elephants to identify individuals since the mid-1960s, when Iain Douglas-Hamilton

Top left and right: The underside of a bull elephant’s hind foot and the resultant spoor imprint he leaves. Researchers have used spoor tracking to study movement patterns. Above: The arrangement of nicks, tears, and holes in the ears of elephants provides a reliable means of identifying individual animals. These marks are acquired during the normal course of events in the life of an animal, but there may be a genetic predisposition, as groups of related individuals often share similar markings.

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began studying the elephants in Lake Manyara National Park, Tanzania. This method is still employed in elephant research as a simple, non-intrusive way to recognize individuals (the animal does not need to be caught and fitted with a marking device). Using this method does, however, require substantial effort if a researcher wants to gather sufficient data to identify patterns of movement, behaviour, and social interaction. Radio tracking. During the Second World War, radar operators noticed that, on occasion, the blips on their screens were not aircraft but flocks of birds. Biologists went on to use radar signatures to study patterns of bird-movement among roosting and feeding areas, and these formed the earliest wildlife telemetry studies (that is, studies using instruments to transmit signals over a distance). Their applicability was limited, however, as researchers could never be certain what it was they were tracking, and only with the development of a workable radio tracking system in the early 1960s did telemetry studies really take off. Radio tracking (or, more correctly, VHFradio telemetry) requires a transmitter unit fitted to the study animal and a combination of a receiver and directional antenna used by the researcher to locate this transmitter. In the study of large mammals, such as elephants, the transmitter comprises a VHF (very high frequency) radio beacon, a battery pack, and a propagating-antenna embedded in a collar. The collar is fitted around the neck of the study animal. Collars typically have radio transmitters of different frequencies so that each animal is uniquely identifiable. The researcher then uses the receiver and directional antenna either to track and find the animal in the field or to plot its position by triangulating bearings taken from two or more locations. Radio tracking has revolutionized the study of wildlife. Biologists can now find specific animals on the ground or from the air, and locate them without needing a direct sighting of the subject. They can gather data regularly on the


animal movements and habitat selection, as changes of behaviour may be seasonal, so it’s useful to know whether patterns observed one year are repeated in other years. In 1991, the US military’s Navigation Satellite Timing and Ranging (NAVSTAR) Global Positioning System (GPS) was made available to the public. A year later, a Canadian company, Lotek Engineering Inc., was commissioned to develop the first wildlife telemetry system based on GPS. After initial tests and refinements, these units were deployed on moose in Ontario in 1995. At about the same time, Save the Elephants (STE) fitted the first GPS collars to elephants in Kenya. These collars use the constellation of NAVSTAR satellites to determine the location of the study animal. The GPS is essentially a passive receiver, the communication signal being generated by the satellites, so these collars require substantially less power to derive a location plot than the earlier satellite systems. Furthermore, the data need to be relayed from the collar to the researcher. Three data retrieval systems are currently available: (1) data are stored in a memory chip within the collar, to be collected when the collar is retrieved or by a local communication link in the field, typically a VHF or UHF radio system; (2) data are relayed via a secondary low earth orbit satellite link, such as the ARGOS system or the

Top: A bull grazing near a dam. Above left and right: Save the Elephants researchers using a directional antenna (two-element yagi) to determine the location, relative to themselves, of an elephant fitted with a VHF-radio collar.

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distribution or movements of specific animals, as well as on the habitats they use. They can also study animals without having physically to be in the same place as them – most wild animals don’t enjoy being close to people, and such proximity has the potential to modify their behaviour and hence the research results. The method does, however, still require someone to be in the field to gather the information, so data tend to be biased toward localities that are accessible, and times in which people are active there. Furthermore, location plots based on the triangulation of bearings derived from VHF-radio typically have an error associated with them of 100–300 m. In other words, the study animal is located within an area of at least 31 000 m2. This determines the smallest spatial scale of these studies, which may be too large to be appropriate for the questions that need to be answered. Satellites. The potential use of satellites for tracking wildlife was first recognized in the mid-1970s and satellite telemetry was seen initially as a way of overcoming the limited signal-distance of VHF-radio telemetry, particularly in remote regions of the globe and on far-ranging species. The first collars, operating off the Nimbus satellite system, were fitted to polar bears. In the early 1980s, the Centre National d’Études Spatiales in France, and the US National Oceanic and Atmospheric Administration, and National Aeronautics and Space Administration (NASA) cooperated to develop the Argos Data Collection and Location System (Argos DCLS), designed to gather environmental data from anywhere on Earth. Collars contain ultra-high-frequency (UHF) transmitters. These send out an identification code and other information to satellites, which collect data as they pass overhead. Ground-based computers use the Doppler effect (shifts in the frequency of the received signal caused by the satellite’s movement) to calculate the animal’s location. Data are then relayed to tracking stations and made available to biologists. Because satellite transmitters send their signals into space, they require substantial battery power, so they’re heavier than radio transmitters. The early transmitter collars, with a life-span of 12–18 months and weighing 1.6–2 kg, were fitted to caribou and polar bears in the Arctic. The results were remarkable. The mean location error of data derived from the Argos system was calculated to be 829 m, and 90% of estimated locations were within 1.7 km of the true location. Satellite telemetry was able to address the problem of accessibility but not that of resolution (or information detail). Also, the costs of manufacturing the collars required are much higher than for those used in VHF-radio telemetry. Furthermore, these collars have a shorter lifespan than that of radio collars with equivalent power packs. This last point is important when studying

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Left: Daily location points of a bull elephant within the Kruger National Park and the reserves forming the Associated Private Nature Reserves along its western border, over the period May 2002 to October 2006. Data points are colour coded according to season to highlight the consistency in his pattern of range use over the years. The red polygon line defines the bull’s 2 800 km2 home range (“minimum convex polygon”) and the red octagon a hypothetical range of 240 km2. ▲

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Inmarsat-3 suite of geostationary communication satellites; and (3) transmission of data via the local GSM cellular network. The option chosen determines the energy demands and hence the lifespan of the collar. The South African-produced GPS–GSM collars currently being used to track elephants in and round the Kruger National Park and elsewhere in Africa are expected to provide hourly location data for at least four years. Given that the GPS-derived location data are accurate to within approximately 10 m, we now have a telemetry device that delivers data more accurately, at a finer spatial and temporal

Above: Fitting a GPS-telemetry collar. To keep it correctly orientated, the telemetry unit is counter-balanced with a lead weight sandwiched between the belting used to ensure the suitable fit of the collar. Left: An adult bull elephant fitted with a collar. Because the GPS needs to access satellites to determine its location, the telemetry unit sits on the dorsal (upper) surface of the elephant’s neck. The collar records the location of the elephant at hourly intervals and relays the data to researchers in the field via the GSM network and Internet.

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resolution, and for a longer period of time than was previously possible. Furthermore, data transmitted via a satellite or cell phone can be retrieved almost immediately from any place with Internet access and, because the communication medium is two-way, the interval at which data are recorded may be rescheduled at any time during that particular collar’s lifespan. Better data So what difference does all this make for the study of animals such as elephants and their conservation? In the mid-1980s, researchers studying elephants within the Timbavati and Klaserie Private Nature Reserves, on the border of the Kruger National Park, fitted 21 bulls with VHF-radio collars. Researchers were able to relocate only five of these animals again 40 times or more over a seven-year period. This highlights the difficulties of finding animals, even those fitted with radio collars. Based on the information gathered, the mean home-range size of the bull elephants was estimated to be approximately 240 km2. Our study of elephant movements within the same area, using GPS-telemetry, has now found bull home-ranges to be of an order of magnitude larger (mean = 2 800 km2). The satellite telemetry has removed our dependence on having someone in the field gathering data; it has provided more data and, therefore, a more realistic impression of elephant distribution patterns across complex landscapes. It also means that we can now follow animals even when they move to places where we don’t expect them to be. Thanks to the new technology, we can understand better how elephants move within these extended home ranges. Our data have shown this movement pattern to be a series of ‘nodes’ (or smaller areas within the larger home ranges) representing high-use areas, which are linked by travel paths. These nodes and travel paths are not only defined by where they are located on the ground, but also by the patterns of how and when the animals use them. In nodal areas, the distance between consecutive location plots (which shows the animal’s rate of movement) was relatively short, and the angles – representing change of direction – large. This pattern of movement might indicate an elephant choosing to remain within a particular area to engage in behaviour such as foraging. Travel paths, on the other hand, revealed relatively large steps between consecutive location points and small angles, reflecting a rapid, directional movement pattern. In other words, when they are within a nodal area, elephants move slowly, and regularly turn back on themselves; when they leave the nodal area and move towards another node, however, they do so relatively fast and tend to stick to the appropriate direction. Such data enable us to identify key resource areas (or, places where important resources may be found, such as dry-season food and water). These areas may be critical to elephant populations, and it’s here that the


Right: The telemetry collar links the wild animal and the researcher, facilitating a relationship that may last from a few months to a few years. Below right: Hourly location plots, during October 2006, for a bull elephant within the reserves making up the Associated Private Nature Reserves. Movements between the data points are shown as red-orange lines linking consecutive location plots. Utilization nodes are defined by movement patterns. The two key nodes (kernel derived 75% probability isoline) are shaded dark green, and two nodes of lesser importance are enclosed within green circles. These analyses highlight areas of intensive use by the elephant during the transition from the dry to wet seasons, an important time of year for any large herbivore that has had to rely on ever diminishing food and body resources to survive the dry season while awaiting relief brought by the first substantial rains of summer.

impact of elephants on the vegetation may be greatest. Similar data sets have been used by STE in northern Kenya to identify important conservation areas that serve as elephant habitat nodes, and the corridors across agricultural areas that link them. Efforts to minimize human– elephant conflicts, therefore, can effectively be focused along these corridor routes for greatest benefit to both humans and elephants. Great advances

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First there was field tracking and direct observation, then came VHF-radio telemetry. Now satellite technology has provided the third major advance in wildlife distribution and movement studies. It means that we’re able to gather more data, at shorter intervals, more accurately, and for longer periods than ever before. Furthermore, we can do so independently of human bias and fallibility. Satellites have opened the door to studies of fine-scale habitat selection by animals in the wild, and, combined with other new data sets such as satellite imagery and remote sensing information, have taken wildlife conservation to new levels of accuracy. As the issues in elephant conservation become increasingly complex, for example, the new technology will help to give us the information we need to design protected areas that are more relevant to species and ecosystem processes than in the past, and to develop management strategies that are more sophisticated, in the hope that we can ensure the continued survival of all wildlife species in tolerant coexistence with humankind. Steve and Michelle Henley work with Save the Elephants. Both with doctorates in wildlife ecology, they are currently studying elephant movements and environmental interactions in the Associated Private Nature Reserves and adjacent Kruger National Park. For more consult the following: I. & O. Douglas-Hamilton, Among the Elephants (New York, Bantam, 1975); I. Douglas-Hamilton et al., “Movements and corridors of African elephants in relation to protected areas”, Naturwissenschaften, vol. 92 (2005), pp.158–163; L. Liebenberg, The Art of Tracking: The origin of science (Claremont, David Philip, 1990); K. Payne, Silent Thunder (Johannesburg, Jonathan Ball, 1988); J. Poole, Elephants (Stillwater, Voyageur Press, 1997); J. Soshani, (ed.). Elephants: Majestic creatures of the wild (San Francisco, Weldon Owen, 1992). See also the special suite of articles on elephant conservation and management in South Africa in the South African Journal of Science, vol. 102 (2006), pp. 385–405. Visit Save the Elephants at www.save-the-elephants.org and for more on telemetry collars visit African Wildlife Tracking at www.awt.co.za.

Above left: Elephants show a high degree of sexual dimorphism (that is, different size and/or shape of male and female bodies) and a large bull can weigh twice as much as an adult cow. This influences the resources they select. The cow, for example, requires a diet of relatively high-quality forage, but less of it than a bull. Cows and family groups therefore tend towards areas with higher-quality food; bulls may move to areas where the forage is of poorer quality but abundant. Above right: The relationship between elephants and people has changed. Originally, elephants were a source of protein and ivory; now people are required to play a protective role, benefiting mainly from the tourist income that elephants generate.

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Fact file Q

Finding out more about elephants ▲

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he area in which we are working (the Kruger National Park, the private reserves to the west of it, and the Limpopo National Park to the east) covers more than 30 000 km2 – roughly equivalent to the size of Belgium, and larger than some African countries such as Equatorial Guinea, Burundi, Rwanda, and Lesotho. It is an important area for elephant conservation and one in which elephant management is an ongoing concern. From an elephant management perspective, two key features of this part of South Africa are the expanding elephant population and the diversity of management agencies and objectives. The focus of our telemetry research is primarily to determine the patterns of elephant movement across this landscape, and to what extent these patterns are explained by changes in habitat conditions, perceived safety benefits, and the social landscape. In other words, are elephant choosing to be where there is sufficient food and water of acceptable quality, are they avoiding areas in which they feel unsafe, are they moving in order to be with other elephants, or are they avoiding specific areas because of the presence of particular elephants? Preliminary results suggest that bulls and breeding herds respond to environmental conditions quite differently. Breeding herds are constrained by the relatively high energy demands of young animals and their diminished ability to move far, so these groups of elephants tend to select areas according to the availability of food and water. In the dry season, for example, they concentrate along the riverine areas. Bulls, on the other hand, seem to be more responsive to the social landscape (that is, the presence of other elephants). Depending on their musth status (musth is a period of heightened sexual activity in bulls) and their size and age, they either seek out or avoid breeding herds. This reaction is most evident in the older, larger bulls, who actively seek out breeding herds during their three months or so in musth. Then, for the rest of the year, while not in musth, they move to areas that the herds seldom use. Younger adult bulls are less likely to move away from the breeding herds when not in musth – they seem to follow a more exploratory pattern of movement, finding their place within the environment and social landscape. Although elephants in our study moved over substantially larger areas than expected, a close look at the data revealed that they did not use the entire area uniformly, but concentrated their activities in 2–4 nodes within the greater area. These nodes are their ‘core range areas’, and contain the essential resources, such as food and water, that the animals need to survive and reproduce. These nodes are linked by travel corridors. We compared our data on elephants that are confined within protected areas with data from a similar telemetry study in Kenya, where the elephants are free to move across farmland to neighbouring protected areas. It would seem that where the elephants have to move across risky areas (that is, where they are more likely to come into conflict with people), their travel corridors are more clearly defined and the rate of movement through them substantially more rapid. These findings suggest that elephants are aware of the spatial and temporal context of risks they face, and respond in ways that will help them

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to avoid danger. They also suggest that efforts to reduce or mitigate conflict between people and elephants can be most effectively applied by focusing on these corridor areas. Our research started in May 2003, and, over the past three and a half years, we have been adding collars to elephants as and when funds allow. At present, we have 25 GPS-collars deployed – 7 on bulls found mainly along the eastern border of the Kruger National Park and 18 on bulls and cows in the private reserves and areas adjacent to the Kruger National Park in the west. Of these elephants, 10 have been monitored for over a year to provide our preliminary results. We expect the collars to last another three and a half years, delivering location data at intervals of 8, 5, or 1 hours, depending on the collar type and number of batteries. The elephants in our study area are largely contained within fenced, protected areas. While there are occasional breakouts, human–elephant conflicts are not as much of a concern as they are in other parts of Africa, where reserves are not isolated (that is, not fenced off) to the same extent from the surrounding areas. Now that the Great Limpopo Transfrontier Park is a reality, however, we may be confronted with this issue to a greater degree in future. Elephants are moving from the Kruger National Park on the South African side into the Limpopo National Park in Mozambique, and, because it is protected, the original population in this area is most likely growing. Local people may find themselves increasingly in competition with elephants and other wildlife for resources. If we are to ensure that both people and elephants have a future in the area, we need to know who uses what resource at what time, and explore ways to partition and protect these resources for the use of all who need them. Currently, however, the big issues facing ecologists and wildlife managers in much of southern Africa relate to elephant densities within protected areas rather than outside them. The main contribution of our research is to understand where elephants are spending most of their time and under what circumstances, so that we can model potential impacts and the consequences of management actions. STE and other researchers in this field are collaborating with SANParks scientists in addressing these matters. ■ Left (from the top): In the dry season (winter), when many grasses have little or no green material, woody vegetation is an important source of forage for elephants. In the wet season (summer), trees provide elephants with refuge from the heat. An elephant recovering after having been immobilized so that a GPS collar could be fitted. Unlike most large herbivores, a darted elephant must lie on its side, not its brisket (chest). Because it is so heavy, keeping it upright would make the gut exert too much pressure on the diaphragm and hinder its ability to breathe. Elephants drink regularly, and also bathe as a means of thermoregulating. Large-bodied animals often have difficulty keeping cool in the heat. Dust bathing is another way in which elephants cool themselves. It has also been suggested that they may be able to absorb certain minerals through their skin.


Q Your Q uest ions answered

How to deal with elephant numbers QUESTION Is there really a problem with elephant numbers in South Africa? If so, is culling the best option or are there alternative solutions? ANSWER No, there are not too many elephants in South Africa. The problem is that many elephants in the country are confined to areas that are too small, while the shapes of many reserves do not consider the animals’ natural movements and land-use patterns. Artificial water points and fences further modify movement and increase population growth rates. The idea that elephant numbers alone are a problem suggests, crudely, that their impacts on the environment result from overpopulation. In reality, impact is driven as much by where elephants are as how many there are. Water and confinement modify the daily, seasonal, and migratory ways in which elephants use space. They depend on water and, during the dry season, remain close to perennial rivers and artificially maintained water points. Through the rainy season, with water everywhere, they can move more freely – as they leave the vicinity of permanent water sources, local vegetation can recover. The natural movement of elephants according to the season thus reduces local impact. When waterholes are established, however, elephants do not shift ranges according to the season, and local impact increases. In addition, fences restrict elephant movement, forcing the animals to use the same areas repeatedly – this is the case in most of South Africa’s parks and reserves. There is no evidence to support the notion that culling reduces the effects. Therefore, management should not focus on culling, but rather on the mechanisms that cause impact – such as the artificial distribution of water, fences that limit movement, and the medium- and long-term consequences of water and fences on the rate at which elephant populations grow. Elephants, like so many species, often die in times of drought, or move away from areas with limited food and water. When confined populations have sufficient resources, it is not surprising that their numbers become artificially high. It does not make ecological sense to treat numbers as the problem, once we know that numbers are symptoms of management decisions. We should rather treat the causes – water and fences. Transfrontier conservation holds great promise. For instance, today’s Kruger National Park represents only one fifth of

the final Transfrontier Park earmarked for the region. Professor Rudi van Aarde and Dr Tim Jackson, Conservation Ecology Research Unit, University of Pretoria

ANSWER At the start of the 1900s there were fewer than 250 elephants in South Africa, the remnants of once vast herds that were ruthlessly exploited for ivory, leather, and meat, and that were cleared out of areas to make way for people and agriculture. Now there are an estimated 17 000 elephants in South Africa, so numbers have successfully rebounded from their earlier low levels. Most of these elephants are in the Kruger National Park and associated reserves, but many small populations have been established in more restricted state and private reserves. As a nation, we no longer face the immediate risk of elephant extinction. The space available to these elephants is a miniscule fraction of their former range, and we now contend with confined populations. Elephants are landscape engineers, in that they can alter the appearance and functioning of areas. Confining the animals in small spaces concentrates and sustains their impact on ecosystems, which has raised concerns. So the ‘problem of elephant numbers’ needs to be redefined in terms of their density and impacts. How serious are these impacts? The Minister of Environmental Affairs and Tourism recently asked elephant experts for advice, specifically as to whether elephant numbers in the Kruger National Park were too high. The experts concluded that there was no scientific evidence that elephant numbers in the Park caused loss of biodiversity. At a localized level and within some of the smaller conservation areas, however, there was evidence for loss of biodiversity and hence the need to manage elephant density. It was recognized that if elephant populations continue growing at the present rate, there could be reason to worry about their impacts on biodiversity in future. Current options to reduce elephant density include range expansion, translocation, and culling. Contraception can also lower the rate of elephant population growth and, if applied for long enough, may reduce elephant numbers. All these options are expensive and each raises concerns. Range expansion means extending existing

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elephant habitat by expanding today’s reserves – as with the dropping of the Mozambique boundary fences of the Kruger National Park and enlarging the elephant habitat in the Addo Elephant National Park. The cost of land and human pressures around conservation areas make this option expensive, with limited opportunities. Translocation means moving animals to previously unoccupied reserves. Again, the opportunities are limited and this option is expensive. Culling has high management costs and is seen by many people as undesirable. Finally, contraception has been shown to be effective in small populations, but there are severe logistical constraints for larger populations. Furthermore, contraception is predicted to bring undesirable behavioural, social, and ecological side-effects. All these options are possible and practical, given sufficient resources to apply them. But we still need to be clear about just how many elephants our conservation areas can support without compromising biodiversity. We do not have an answer to this question – yet this answer is fundamental in deciding how many elephants need to be affected by management (through translocation, culling, or contraception). A new, national research initiative was launched this year to deal with the issue, and will soon – we hope – start to guide the decision-making. ■ Professor Graham Kerley, Centre for African Conservation Ecology, Nelson Mandela Metropolitan University, Port Elizabeth For up-to-date research on elephant conservation and management, consult the special suite of articles published in the September/October 2006 issue of the South African Journal of Science, vol. 102, pp.385–405: R.J. van Aarde, T.P. Jackson, and S.M. Ferreira, “Conservation science and elephant management in southern Africa”; N. Owen-Smith, G.I.H. Kerley, B. Page, R. Slotow, and R.J. van Aarde, “A scientific perspective on the management of elephants in the Kruger National Park and elsewhere”; G.I.H. Kerley and M. Landman, “The impacts of elephants on biodiversity in the Eastern Cape Subtropical Thickets”; and A.K. Delsink, J.J. van Altena, D. Grobler, H. Bertschinger, J. Kirkpatrick, and R. Slotow, “Regulation of a small, discrete African elephant population through immunocontraception in the Makalali Conservancy, Limpopo, South Africa”. E-mail your questions to the Editor (write S&T QUESTION in the subject line) at editor.quest@iafrica.com OR fax them to (011) 673 3683. Please keep questions as short as possible, and include your name and contact details. (We reserve the right to edit for length and clarity.)

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Measuring up Q Museum measures Here are some facts from the Smithsonian National Museum of Natural History in Washington, dc. n It has one of the largest plant fossils ever collected: 3.9 metres long and 3.7 metres high. It’s a ‘scale tree’, or lycopsid, which lived in a great swamp 310 million years ago. The specimen comes from a coal mine in Iowa. n It has a living specimen of the ‘titan arum’ plant, which bloomed for the first time in January at the age of 14. The rare Amorphophallus titanium, native to Sumatra, flowers for only a few days – which is just as well, because it smells like rotten meat. And there’s a lot of it: the average recorded height of the flowering part of the plant is 1.5 metres. n It contains 124 million biological, geological, and anthropological objects and specimens. How does it measure the ‘health’ of its collections? Well, it has developed a process which looks at six criteria: conservation status (preservation), processing state (degree of sorting and labelling), storage containers, arrangement (ease of finding the item), identification, and inventory (database record). A numerical score is awarded for each of these indicators. The ‘profile units’ assessed include shelves, drawers, tanks, and slide boxes. The resulting profile shows up problem areas for the museum to attend to.

Collection mania At London’s Natural History Museum, the entomology department has a collection of about 28 million specimens of insects – the most comprehensive in the world. It represents about half of the described species, which number more than a million. The botany department has more than 6 million specimens and the zoology department 30 million. Mineralogy’s collection numbers a third of a million. Palaeontology has about 9 million items, the oldest fossils dating back over 3 500 million years – their sizes range from elephant skulls to microscopic specimens.

Migration distances Satellite and tracking equipment allows us to measure animal migrations (see page 3). The humble herring, only 30 cm long, can travel 3 000 km. Other round trips include the Arctic tern’s 20 000 km, the wandering albatross’s 15 000 km, the swallow’s 10 000 km, the yellowfin tuna’s 8 500 km, and the eel larva’s 3 000 km. The northern fur seal logs 5 000 km and the green turtle 4 600 km. (Source: BBC) Leatherback

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turtles have been found more than 4 800 km from their nesting beaches. Their average swimming speed is 2.5 km per hour and they have been recorded diving down more than 1 000 m.

A – Z of instruments The Phrontistery is a wonderful free online dictionary of obscure words. (The term comes from the Greek phrontistes meaning ‘a thinker’.) Here are some of the 400 scientific instruments and tools it lists and, in brackets, what each of them measures: n actinometer (incident radiation) n aethrioscope (temperature variations due to sky conditions) n auxanometer (growth of plants) n bolometer (radiant energy or infrared light) n coulombmeter (electric charge) n elatrometer (gaseous pressure) n galactometer (specific gravity of milk) n goniometer (angles between faces) n konimeter (amount of dust in air) n oncosimeter (variations in density of molten metal) n phthongometer (intensity of vowel sounds) n plemyrameter (variations in water level) n pyknometer (specific gravity) n sillometer (speed of a ship) n sympiesometer (pressure of a current) n zymosimeter (degree of fermentation).

Bee sure The Journal of Measurement Science & Technology reported at the end of 2005 on a new, capacitance-based sensor for monitoring bees passing through a tunnel. Such a sensor could be used in many ways, it was suggested, including sensing manufactured objects and coins in vending machines. Monitoring bee activity around hive entrances, though, relates to foraging patterns among bees that pollinate commercial crops. Two pairs of capacitor electrodes are arranged around a tube. Capacitance increases when dielectric material – in this case, a bee – passes between the electrodes. Measuring the difference in capacitance between the two capacitors cancels out changes in the tunnel that may result from temperature, humidity, and pollen coating. The method measures bee size and velocity as well as numbers.

Categories of chaos Measures of storm intensity combine with economic measures for assessing how natural disasters can affect nations and ordinary people. The Saffir Simpson Hurricane Intensity Scale relates a storm to its potential for damage. Category 5 hurricanes are characterized by sustained wind speeds

of greater than about 250 km/h and tides rising by more than 5.5 m. They do major damage to the lower parts of structures less than 4.6 m above sea level. The 2005 hurricanes Wilma, Katrina, and Rita were all category 5 hurricanes. The 2004 US hurricane season cost $60 billion in economic losses, of which only half were insured, according to an article in Science (12 August 2005) by Evan Mills. The 2005 season was the worst since record-keeping began, with 26 named storms killing 1 300 people. By the end of November, insurance claims of $50.3 billion had been filed. Statistics presented to the United Nations Climate Change Conference in Montreal in December 2005 indicated that 2005 had “witnessed the largest financial losses ever as a result of weather-related natural disasters linked by many to human action, more than $200 billion compared to $145 billion in 2004, the previous record.” According to the February 2007 report from the Intergovernmental Panel on Climate Change, rising sea-surface temperatures correlate strongly with the observed increase in the number of category 4 and 5 Atlantic hurricanes between 1970 and 2004.

Egg-zact facts A Quantitative Computed Tomography scanner at the University of Alberta, Canada, is being used to measure the bone density of laying chickens, so as to find ways to prevent osteoporosis and bone breaks in the birds. The new method allows the birds to be scanned alive, which also means more data can be obtained from each bird over time. (Science Daily, 26 December 2006)

Come to your sensors n Last year, the National Institute of Standards and Technology in the USA presented the first precision instrument for directly measuring alternating current (AC) voltages. It is based on ‘Josephson junction’ technology, which in turn is based on quantum physics, and should improve measurement accuracy by as much as 1 000 times. It is to be used in industrial voltmeters, spectrum analysers, amplifiers, and filters. n How small can a machine be? In 2005, physicists managed to measure “how close speeding atoms can come to a surface before the atoms’ wavelengths change”. This has implications for nanotechnology, which involves tiny devices measured in ten-billionths of a metre, and for atomic optics, which involves making precise sensors. Compiled by Ceridwen


Corné Eloff explains the purpose and the workings of South Africa’s access to new high-resolution SPOT 5 satellite earth observation technology.

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turnaround times from the acquisition of data to its availability to end users (the current norm for turnaround is three weeks, but is in the process of being reduced to as little as one week). The milestones associated with the SPOT 5 project relate to this new direct access to the data and the opportunities it gives us to learn, build capacity in terms of staff skills and expertise, and upgrade the infrastructure (the hardware and software) required for the work.

Pictures courtesy of the CSIR

Improved, usable data The ‘mosaic product’ covering South Africa is a one-off dataset. It uses the same, uniform spectral (that is, combining colour and light) and spatial resolution imagery, gathered between August 2005 and March 2006. Until now, the highest-resolution nationwide mosaic available was in the form of 15-m pixels4 from the Landsat 7 satellite,

with imagery collected in 2000–2001. The 2.5-m mosaic from SPOT 5 offers more recent – and more detailed – data5. With this new higher-resolution information, land-cover and land-use can be classified more precisely in future. It will also bring many hithertoimpossible applications. In the past, for instance, the resolution was too coarse to give a clear picture of urban

Above left: A SPOT 5 image of the area between Diepsloot and the southern suburbs of Centurion. It reveals the difference between informal settlements (centre right) and the more structured layout of urban areas. Middle: South Africa’s first 2.5-m natural-colour seamless mosaic dataset, created from SPOT 5 data. Right: The 5.4-m X-band antenna that the CSIR uses to collect data from the SPOT satellites.

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n 20 April 2007, at the CSIR Satellite Applications Centre facility at Hartebeesthoek, the Deputy Minister of the Department of Science and Technology formally launched South Africa’s access to new, sophisticated earth observation technology. It will help us to view the entire country’s features in greater detail than ever before, and see more clearly how the land surface is changing and developing in urban as well as in rural areas. Observing from satellites what’s happening on South Africa’s land surface is not new. Through international agreements, access to Landsat1 data since 2000 made it possible to monitor the national landscape. Now, a new multi-government licence agreement is giving the country’s government departments, research institutions, and academia three years of direct open access to detailed information from the SPOT (Satellite Pour l’Observation de la Terre) constellation of earth observation satellites2. The agreement, which runs until March 2009, includes wireless communication that allows data to be received directly from these satellites3. The access has given the country an unprecedented opportunity to create its first national 2.5-m natural-colour seamless mosaic dataset (that is, a set of images of every part of the country, which, when joined together, give a complete, detailed picture of the nation’s land surface). South Africa has never before had such high-resolution spatial data available for the nation as a whole, collected over such a short period (just eight months). The direct open access to SPOT data allows many images to be produced, as well as good

1. The first United States Landsat satellite was launched in 1972 and the most recent, Landstat 7, in April 1999. (These satellites typically have a limited lifespan of about five years.) The millions of archived Landsat images are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, education, and national security. Landsat 7 data have eight spectral bands with spatial resolutions ranging from 15 to 60 metres – meaning that you cannot pick out individual houses on a Landsat image but you can see large man-made objects such as highways. Landsat operates in a Sun-synchronous orbit and passes over the same area every 16 days. 2. The SPOT constellation, funded by the governments of France, Belgium, and Sweden, is operated by the French national space agency, CNES (Centre National d’Etudes Spatiales), from Toulouse, France. SPOT 1 was launched in February 1986 and SPOT 2 in January 1990. SPOT 3 went up in September 1993 but was lost following a technical error. All three carried identical instrument packs: the High Resolution Visible (HRV) instrument can take a 10-m panchromatic as well as three different types of 20-m multispectral image. SPOT 4 went into orbit in March 1998, with an added channel in the mid-infrared region; SPOT 5 was launched in May 2002, carrying a new stereo instrument, an enhanced panchromatic channel, and a four-band multispectral imager. The multispectral spatial resolution is provided by an array of instruments that create images in different wavebands. The orbit of the SPOT constellation is near-polar (that is, in an orbital plane crossing the poles), Sun-synchronous (meaning that it revisits any point on the land surface at the same local time of day). It circles at an altitude of 832 km and an inclination of 98.7°, with a period (that is, the time it takes to go once around the Earth) of 101.5 minutes. Having previously had access to data from SPOT 2 and 4, the CSIR has been able to receive SPOT 5 data since October 2006. 3. The direct data-acquisition system is owned and operated by the CSIR, from the X-band antenna to the advanced geo-processing system to automate the image rectification and mosaicking processes. 4. A pixel (short for ‘picture element’) is one of the tiny dots that make up an image. In earth observation, a ‘15-m pixel’ means that a single pixel on the image denotes an area of 15 m2. 5. The SPOT 5 data providing national coverage of South Africa had been collected by March 2006, and the geometric correction of the data was completed at the end of January 2007. The true-colour reconstruction of the 487 pan-sharpened images to build the national mosaic, completed at the end of March 2007, was released to users a month later.

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and periurban developments. The new data will, for the first time, allow government to identify smaller-scale changes in and around towns and cities, and, as a result, to improve urban management and planning (regarding appropriate service delivery, for instance). The mosaic over South Africa is packaged in colour, using the RGB model (in which red, green, and blue combine in various ways to reproduce other natural colours). One RGB image that covers 60 × 60 km is about 3 Gb in file size, however. Given that national coverage of South Africa requires 487 such images, a file containing the complete mosaic would exceed 1.4 Tb in file size – far too large to work with or to upload onto a ‘normal’ workstation or desktop computer. For convenience, therefore, the CSIR has created a grid over the mosaic, cutting the large national file into blocks (or ‘tiles’) of manageable size, that is, 50 × 50 km square. The tiled mosaic will enable users to upload a specific geographic area of interest. In short, this packaging makes it possible to manage and use the data efficiently. SPOT 5 coverage and how it works Remote sensing depends upon observed spectral differences in the energy reflected or emitted from distinctive features – that is, we look for differences in the ‘colours’ of objects, to distinguish, for instance, between towns and maizefields. This principle forms

the basis of ‘multispectral’ remote sensing (that is, the science of observing features in the landscape at varied wavelengths so as to derive information about these features and their distributions). The SPOT 5 national coverage consists of 2.5-m natural-colour imagery, 2.5-m black and white imagery, and 10-m multispectral imagery at various spatial resolutions to serve different users’ needs. The accuracy of the SPOT-satellite data is due to an instrument called the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite), which works out the orbital position of the satellite to within a few centimetres. The information is then used to calculate the position of each pixel in relation to the ground surface and to express these results as a map projection6, using a procedure called ‘geometric correction’. Why is correction necessary? Every remotely-sensed image represents a landscape in a specific geometric relationship between actual points on the ground and their corresponding representations on the image. This relationship is determined, for instance, by the design of the remote-sensing instrument, the operating conditions, and the terrain relief (or, the altitude of the land surface). The ideal remote-sensing instrument would create an image with an accurate, consistent geometric relationship between topographical

6. A map projection such as Universal Transverse Mercator is a grid coordinate system that can be applied to maps of the Earth’s surface extending to latitudes of 84 °N and 80 °S. Mercator projection ensures true representation of shape but not of area. 7. For geometric correction and accuracy, the CSIR uses the best reference data locally available. It entails aerial photography orthorectified by the Chief Directorate of Surveys and Mapping (CDSM); land-survey urban property delineations; and 20-m DEMs (digital representations of ground surface topography or terrain) generated from 20-m 1: 50 000 topographic map contours published by the CDSM. Orthophotos (the preferred reference dataset) are not available for the entire country, so urban cadastral reference points are used in the gaps. The limitation of the new South African mosaic is the lack of national-scale reference data (such as full aerial photo coverage or high-resolution DEM) for precise country-wide geometrical accuracy. Furthermore, the 2.5-m spatial resolution provides limited objectidentification resolution when compared with very high-resolution sensors such as those of the commercial earth observation satellites QuickBird or Ikonos, which provide <1-m resolution pixels. These satellites cannot produce national coverage, however, so they do not have the level of feasibility that SPOT offers.

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features and pixels, from which areas and distances could be measured accurately. In reality, each image includes positional errors caused by the perspective of the sensor optics, the motion of the scanning optics, terrain relief, and Earth curvature. Such errors vary in significance, but they are inherent, not accidental, characteristics of remotelysensed images7. South Africa’s access to SPOT 5 (without ignoring SPOT 2 and 4) yields remotesensing imagery with an acceptable revisiting time period of once a month, to ensure multi-time-series data for detecting changes on the land surface. Creating the 2.5-m national mosaic provides a significant ‘base map’ for auditing the country’s land use and land cover and for comparisons over time. Usefulness The new high-resolution data has many uses. Here are just three examples. ■ The ‘residential informal’ class of land use (representing informal settlements) can now be determined, measured, and monitored as it alters. When images of the same area are collected at different times, spatial analysis can pick up changes – did a settlement grow, for instance, or did it shrink because of a successful low-cost housing project nearby? ■ Monitoring crops and yields for wheat or maize provides important information for the Department of Agriculture and helps the country to assess its level of food security. ■ The monitoring of land-use classes – such as residential houses, industrial areas – can be aligned with geographically coded crime data to illustrate spatially the relationship between crime incidents and changes in the environment. If, for


Q News Revolutionary wireless connections

Far left: Image of a multidisciplinary extraction from the national dataset, highlighting different areas of application such as urban planning, agriculture, and vegetation. Middle (above): The CSIR’s X-band antenna. Middle (below): CSIR remote-sensing technician, Joel Sekwakwa. Right: The image of Cape Town and False Bay is a pseudo-natural-colour product of two orthorectified SPOT 5 scenes, which was pan-sharpened (2.5-m pixel resolution) and mosaicked to produce the map. The insert is a digital map projection (DEM) of Table Mountain, viewed across Table Bay. For more on remote sensing visit www.fas.org/irp/imint/docs/rst/index,html

example, there is a large new property development in an area, and house burglaries have increased since the project began, targeted crime-prevention strategies can be planned. Value for money The normal retail cost of one 2.5-m natural-colour orthorectified image from SPOT 5 is approximately R100 000.00 (10 000 euros). Therefore the South African mosaic as a whole has a market value of over R40 million. The agreement between the CSIR and Spot Image (the French distributor of SPOT information and products) for the three years of open access gives us the data at about a quarter of the normal cost. With better data will come better decision-making, and all South Africans will benefit. Space technology is complex and expensive. It depends on know-how, operational excellence, and high levels of engineering expertise. In the spirit of the Spatial Data Infrastructure Act (Act No. 54 of 2003) – which provided for the establishment of the South African Spatial Data Infrastructure (SASDI) to regulate the collection, management, maintenance, integration, distribution, and use of spatial/geographic information – the SPOT programme hopes to make its contribution to South Africa’s national space programme, and to the SumbandilaSAT microsatellite to be launched into orbit later in 2007. ■ Dr Corné Eloff, manager of the Earth Observation Service Centre, CSIR Satellite Applications Centre, has worked closely with Spot Image over many years and was responsible for negotiating open access for data from the SPOT 2, 4, and 5 sensors for government departments, research institutions, and academia in South Africa.

The radio is 110 years old this year and the microprocessor nearly 50. By moving ever closer, the two technologies are extending the benefits of the computing world (including innovation and low cost) to that of wireless communications. They are connecting objects to each other without people having to intervene in what a 2005 United Nations agency report called “The Internet of Things”. America’s National Research Council predicted in 2001 that the phenomenon “could well dwarf previous milestones in the information revolution”. So far, cellphones have been the focus, with about 2.8 billion already in use, and a further 1.6 million added each day. The industry as a whole (including handset-makers, software developers, and network operators) is estimated to have revenues of some US$1 trillion a year. Although the technologies exist, it will take a while for machine-to-machine (M2M) communications and sensor networks to become the stuff of everyday life, because the right kind of integration between communications and computing still needs to happen and business models need to be developed. At present, individual systems are tailor-made, but current developments have revolutionary implications. According to Moore’s law (named after Gordon Moore, a co-founder of Intel, the world’s biggest chip company), the processing power of chips doubles about every two years. Their billions of transistors get smaller and extra functions are added, helping the chips to go faster and do more. Integrating new functions is relatively inexpensive. In just five years, the cost of a $50 Texas Instruments cellphone chip has dropped to around $5, and that of a $250 phone to $25. Radio chips used for the Global Positioning System or for Bluetooth wireless communications now cost as little as $1 and are the size of a matchhead. A radio-frequency identification (RFID) tag, which sends a tiny quantity of data over a short range when activated, can now be manufactured for 4 cents. Last year a billion RFID chips were sold; this year the number is expected to reach 1.7 billion.

As things communicate with each other affordably, applications are becoming more common. For example, most logistics companies in America and Europe track their fleets with a combination of satellites and cellphone networks. Small wireless sensors monitor factory equipment and warn of impending breakdown. Others fitted to buildings, bridges, and roads are used to identify structural stress and early cracks. Retailers, hospitals, and the armed forces manage stock levels using RFID tags. In Japan, tests are in progress on cars with wireless systems that will prevent collisions. Lighting, heating, and air-conditioning in hotels and offices can be controlled centrally, via a PC or the Web, with wireless technology offering lower installation costs and greater flexibility than a wired system – and savings as high as 25% on energy bills. The medicinal uses of wireless technology are also developing fast. Pacemakers have for decades helped people to maintain a steady heartbeat, but smaller, more powerful devices bring new opportunities. The PillCam, for instance, developed by Given Imaging in Israel, is a tiny two-sided camera the size of a large pill that patients swallow. Since 2001, it has been used in more than half a million gastro-intestinal endoscopy tests, snapping a pre-set number of pictures per second and sending them wirelessly to a data recorder worn on the patient’s waist. The images are then downloaded to a computer for diagnosis; the $450 capsule passes through the bowel naturally and is flushed down the toilet. Advances in wireless technology will continue to raise new questions, such as those around security and privacy. Having patented a technique for tracking people in public places based on RFID tags in their clothing or the products they carry, for example, American Express has agreed not to use it without disclosing the fact. The European Commission is set to issue guidelines on privacy and security standards for RFID technology later this year. From “A world of connections”, a special report in The Economist (28 April–4 May 2007).

Helping the blind to see In a paper published at the end of April 2007 in the Proceedings of the National Academy of Sciences, John Pezaris and Clay Reid of the Harvard Medical School showed how, in time, medical technology could help to restore sight to the blind. It has become common for cloudy lenses (or cataracts) to be replaced with clear, artificial ones that help people to see more clearly. In a far more complicated procedure in 2002, six people in Los Angeles had electronic sensors implanted in their retinas that replaced the photoreceptor cells they had lost to the disease called retinitis pigmentosa. Those implants contained electrodes, which activated pixels, thus enabling the patients to detect a light source and distinguish simple objects such as cups and plates. Now Pezaris and Reid have investigated a way of creating artificial sight, in which instead of the eye sending coded impulses to the brain as in normal sight, the eye is bypassed altogether in the process of bringing vision. They examined a region of the brain called the lateral geniculate

nucleus (LGN), which receives coded impulses and sends them to other regions for processing. At the LGN stage of the brain’s visual pathway, the nerve cells are arranged as a kind of map of the retina. The researchers inserted tiny electrodes into the LGNs of two monkeys, allowing nerve cells in those areas of the brain to be activated as if the impulse had come from a part of the retina. Their results showed that the monkeys could ‘see’ a light flash in these conditions. The experiment worked for a single pixel and in monkeys. But this proof of concept shows Pezaris and Reid that their work could eventually form the basis for a wireless device with many electrodes touching different parts of the LGN simultaneously. The implant could receive a signal from spectacles containing a digital camera, and a hundred or more pixels would be needed. But a start has been made. Reported in “Optical illusion”, The Economist (28 April–4 May 2007).

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A KhoeSan survival story Alan G. Morris explains how groups of people evolve, interact, and adapt as conditions change. The story of the KhoeSan peoples over the past 100 000 years shows that genes, environment, and social identity have combined for long-term survival. Definitions Gene: a unit of heredity, composed of sequences of nucleotides in the DNA molecule, that determines a particular characteristic of an organism (for details, see “Understanding DNA” in Quest, vol. 1, no. 3, p. 25). Gene marker: a gene sequence that is found at a higher or lower frequency in a particular group of individuals, and that marks this group as being distinct from other groups. Used by geneticists to track ancestry of individuals. Morphology: the form and structure of organisms (in particular their external shape and size). Ethnicity: the characteristic traditional and cultural traits that members of a particular human group have in common. (This is not the same as ‘race’ because biology is not part of the definition.) Differential mortality: a comparison of differing rates of death. People who die at a younger age, and who do not have the opportunity to produce enough offspring, leave fewer descendants in the long run. Natural selection: the process that, according to Charles Darwin, brings about the evolution of organisms. Darwin noted that variations exist between individuals in a population. He concluded that disease, competition, and other influences acting on the population eliminated those individuals less well adapted to their surroundings, and that the survivors would pass on to their offspring any heritable characteristics with survival value. Over time, this process could give rise to the development of animals and plants very different from the original population. KhoeSan: The name Khoisan representing the ‘Bushmen’ and ‘Hottentots’ was coined in the 1920s and is now used in preference to the older names that have developed pejorative connotations. The current spelling reflects modern pronunciation and the capitalized ‘K’ and ‘S’ give equal prominence to both groups.

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enetic research in the last two decades paints a new picture of human variation in Africa with more detail than was ever thought possible before. But we still have only the bare structure of the story. Living people have a tapestry of identities: genetic*, morphological*, and ethnic*. We have tools for tracking the genetic threads, but we don’t as yet understand how the long residence and history of people in this part of the world has shaped the way they look. To reconstruct Africa’s past, we need models that explain the genetic patterns as well as the physical appearance that we discern in the living. These models need to include conditions that created isolation, through circumstances (such as severe climate) that blocked interaction with other groups for a time and that reduced the exchange of genes among them. In such contexts, the natural selection process chooses specific and distinctive morphologies (or visible characteristics) that have survival value and passes them on to new generations. The archaeological history of southern Africa indicates that such conditions arose at certain times during the fluctuating environments and climates of the last 100 000 years, shaping the ways in which the KhoeSan peoples developed. The story of their dynamic interactions with other populations in subsequent periods, too, can help us to understand more clearly the complicated ways in which the people of Africa have evolved over the ages. Isolation and climate change Morphologists have shown that modern African populations have distinctive regional patterns, but,


Left: Hunter-gatherers of the Kalahari.

Photograph: Gallo Images

Above: Woman making a necklace. She breaks up pieces of ostrich-shell, uses a sharpened spike to drill a hole through each, then strings them onto a thread made of vegetable fibre. Photograph: Cyclops

Top: Drawing of Khoekhoe people with oxen at the Cape. Reproduced courtesy of the National Library of South Africa (drawing reference INIL 6256v)

Above: Children of the Kalahari in a street in Ghanzi, western Botswana. Photograph: Cyclops

Left: Location of the extended coastal plain, south of today’s southern Cape Province of South Africa, during the Last Glacial Maximum at ca. 18 000 years before present. The human population would have been restricted to the coastal plain and the neighbouring mountains. The land north of the Cape Folded Belt would have been excessively dry and effectively depopulated. 200 km LEGENDS national boundaries limit of coastal mountain ranges extent of shoreline at Late Glacial Maximum

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in fact, no modern African populations are truly isolated from others. To complicate the picture, genetic, and social evidence suggests the presence of a strong pressure among traditionally foraging people (that is, those who travel over distances in search of food) to intermarry with others from distant or unrelated groups, rather than to restrict themselves to partners closer to home. In other words, they go out of their way to increase gene flow rather than to limit it. There is no reason to believe that prehistoric foragers were any different. In the late 1990s, evolutionary anatomist Marta Lahr and evolutionary ecologist Robert Foley suggested that population numbers were greatly reduced at times during the Late Pleistocene (between 10 000 and 100 000 years ago). This gave localized populations in isolated refugia1 the opportunity to adapt under the influence of natural selection. Physical features, which in today’s world seem relatively insignificant, could have provided additional survival value in periods of extreme climatic pressure, and as these characteristics were passed on, each region would have followed its own distinct morphological pathway. Today’s regional morphological differences (features that are sometimes called ‘racial’) are therefore just a shadow of our older past in those groups that survived the rigours of the reduced demography of the Late Pleistocene. The most recent of the stressful climatic cycles occurred at the Last Glacial Maximum (LGM), approximately 26 000–13 000 years ago. Cooler temperatures at this time increased the size of the icecaps, lowered ocean levels, and caused 1. Refugia are geographical regions that remain unaltered by climatic change affecting surrounding regions and that, therefore, act as a protective haven.

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rocky hills lagoon and barrier coastal plain 100 km

Above: Coastal landforms at the Last Glacial Maximum. Reproduced from P. Mitchell, “A palaeoecological model for archaeological site distribution in southern Africa during the Upper Pleniglacial and Late Glacial”, in C. Gamble and O. Soffer (eds.), The World at 18 000 BP, Vol.2: Low Latitudes (London, Unwin Hyman, 1990)

Top: The Cape Peninsula from the north. Photograph: Alan G. Morris

extensive drying in the inland areas of southern Africa. The evidence from southern Africa shows the consistently low population density throughout the Late Pleistocene culminating in a marked population ‘trough’ at the LGM. The southern refuge appears to have been in the Cape coastal mountain range and on the coastal plain that extended out into the ocean by at least 100 km off Cape Agulhas. This refuge was occupied until the end of the LGM, when populations slowly began to recover in numbers. At first, the unstable late glacial environment fluctuated between cold and warm phases causing even greater population stress but, by 12 000 years ago, the climate had stabilized into a pattern similar to that of today. The better climate opened up more ecosystems, and people began to move out of the refuge of the southern mountains and coastal plains, migrating northward into all of southern Africa’s habitats. The difficult times during the isolation in the far south would have led to differential mortality – individuals with distinct morphology could have become more common and the developing KhoeSan people would have begun to differ from people elsewhere in Africa. The KhoeSan after the Late Glacial Maximum The climate at the LGM that isolated the ancestors of the KhoeSan peoples in the far south of the continent could explain the origin of their distinctiveness. It also presents a model in which KhoeSan populations expanded at the

onset of the Holocene (about 10 000 years ago), suggesting that the subsequent differentiation of the KhoeSan peoples in southern Africa is a post-Pleistocene event. The idea that the KhoeSan people had become distinctive in their southern refuge and dispersed from there at the end of the LGM has some important implications. It suggests that that the living San of the Kalahari are not an ancient remnant group, but are the result of recolonization in the early Holocene starting about 10 000–12 000 years before the present. At the end of the LGM, when the climate became friendlier to human occupation, other populations waiting out the bad times in more northern refugia would, like the KhoeSan in the south, have begun to return to the wider environment. Once the KhoeSan had resettled the open interior of the subcontinent, a new ‘stable’ frontier would have developed in the north between them and their neighbours, the non-KhoeSan foragers of central Africa. The Kunene–Zambezi line, which seems to have been the approximate northern limit of KhoeSan people in modern times, was in fact a stable frontier between northern and southern foragers rather than the last line of retreat of the KhoeSan from an earlier more extensive distribution. Supporting these conclusions is the fact that no archaeological skeletons from East or Central Africa (that is, north of the Kunene– Zambezi line) have KhoeSan characteristics, and that living East Africans appear to have no morphological links to living KhoeSan people2. What kind of gene flow would we expect due to the existence of a stable frontier separating different groups of hunter-gatherers with similar economic modes and equal technologies? Because of the general low density of these populations, intermarriage would have formed part of their social outlook despite linguistic or cultural differences. This would, over time, have introduced some genetic intermixture across the geographically widespread population, but the differences in morphology would have remained, because the low population density would have limited the impact of the gene flow. The long-term relationships that had developed over a period of some 8 000–10 000 years among these foragers would have changed greatly in the last 2 000 years as both northern and southern hunter-gatherers came into contact with populations having distinctly different economic and technological habits, especially the Bantuspeakers bringing iron and agro-pastoralism. The perceived social inequality among groups would have resulted in single-directional gene flow, with forager individuals joining agricultural–pastoral communities rather than the other way round. The direction of the flow would have been towards the group with a ‘higher’ socio-economic position (the Bantu-speaking farmers), and this would have helped to maintain KhoeSan genetic distinctiveness even as the historic populations were reduced in numbers through competition. The final demise of the KhoeSan as the demographically dominant population in the

2. The only possible evidence that might support more ancient KhoeSan occupation in East Africa is the presence of click languages and some faint genetic similarities of modern Ethiopians with living KhoeSan. It has been suggested, however, that these more probably reflect a very ancient pan-African pattern rather than a specific KhoeSan one. The morphology that we currently recognize as KhoeSan appeared only relatively recently, and is a southern African, not an eastern African phenomenon.

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south has been well recorded by historians. They were progressively ecologically marginalized and, by the late 19th century, few of the original populations had survived as significant ethnic groups. This destruction was magnified through active genocide in parts of colonial South Africa. Commandos were assembled in the 1700s that systematically attacked San bands on the margins of the growing colony to prevent stock theft and to capture women and children for labour on the farms. This pressure slowly reduced the San groups to servitude or extinction. Cultural change and identity From the KhoeSan perspective, recent history has been an ethnic disaster. This does not mean it was necessarily a genetic one. For the most part, ethnically identifiable Khoe and San populations have been all but lost over the past two centuries. Genetic surveys among living South Africans indicate the presence of many KhoeSan gene markers*, however, and there has also been a remarkable ethnic demographic renaissance during the last 10 years. Both are linked to socio-political developments. The group that the pre-1994 South African government labelled ‘coloured’ became, to a large extent, a genetic reservoir of KhoeSan variability, and many individuals maintained both the spectrum of KhoeSan genes and the KhoeSan morphology. For many rural ‘coloured’ people, transformation from KhoeSan to ‘coloured’ was an entirely cultural transmutation rather than a biological one. Human biologist George Nurse referred to this transformation as “metempsychosis” (a term he borrowed from Christopher Marlowe’s 17th-century play, Dr Faustus), which literally means ‘to transfer a soul from one body to another’ but which, in this context, means ‘to transfer one’s culture to another’. If culture is the soul of group identity, then the term is far from inaccurate. The most recent and ongoing KhoeSan metempsychosis has been the renaissance of the Griqua. From a small ethnic group of several thousand historically KhoeSan people in the northern Cape, it has grown to over 100 000, according to the 1985 census of South Africa. This increase shows the power of ethnic identity transformation, as all these people claim KhoeSan

ethnicity – some by genetic background and some by association. They are claiming KhoeSan identity as part of ethnic pride in their position in the new South African mosaic. Most important, perhaps, is the reminder from the Griquas that genes alone do not define human populations. Biological origin (which can be identified both in gene markers and visible morphology) and ethnic grouping are independent variables: they are influenced equally by the conditions of life in communities, by their history, and by their social structures. ■ Professor Alan G. Morris is in the Department of Human Biology in the Faculty of Health Sciences at the University of Cape Town. He has published extensively on the origin of anatomically modern humans and on the history of physical anthropology in South Africa.

Top left: A self-contained group living in the bush in western Botswana, engaged in different activities. They are following a ‘modern traditional’ lifestyle. The man in the foreground (left) with the anvil and ‘hammer’ is fashioning a spearhead. Photograph: Cyclops Top: Women preparing thatch for the roof of a house built of concrete blocks. Photograph: Cyclops Above: The burial of a Later Stone Age hunter (Hora 2) from 3 000 years ago in the highlands of Malawi, which formed a refugia in south-central Africa. Reproduced from J. Desmond Clark, The Prehistory of Southern Africa (London, Pelican, 1959)

For the scientific evidence of population movements in and out of the southern refuge, consult M.M. Lahr and R.A. Foley, “Towards a theory of modern human origins: geography, demography, and diversity in recent human evolution”, Yearbook of Physical Anthropology, vol. 41 (1998), pp.137–176; P. Mitchell, “A palaeoecological model for archaeological site distribution in southern Africa during the Upper Pleniglacial and Late Glacial”, in C. Gamble and O. Soffer (eds.), The World at 18 000 BP, Vol.2: Low Latitudes (London, Unwin Hyman, 1990), pp.189–205; and L. Wadley, “The Pleistocene Later Stone Age South of the Limpopo River”, Journal of World Prehistory, vol. 7 (1993), pp.243–296. For the genetics of KhoeSan populations, consult A. Knight et al., “African Y chromosome and mtDNA divergence provides insight into the history of click languages”, Current Biology, vol. 13 (2003), pp.464–473; O. Semino et al., “Ethiopians and Khoesan share the deepest clades of the human Y-Chromosome phylogeny”, American Journal of Human Genetics, vol. 70 (2002), pp.265–268; and H. Soodyall, A Walk in the Garden of Eden: Genetic Trails into our African Past (Cape Town, HSRC Publishers, 2003). For the KhoeSan in history and prehistory, consult A.G. Morris, “The Griqua and the KhoeKhoe: biology, ethnicity and the construction of identity”, Kronos, no. 24 (1997), pp.106–118; A.G. Morris, “Isolation and the Origin of the Khoesan: Late Pleistocene and early Holocene human evolution at the southern end of Africa”, Human Evolution, vol. 17 (2002), pp.105–114; A.G. Morris, “The myth of the East African ‘Bushmen’”, South African Archaeological Bulletin, vol. 58 (178) (2003), pp.85–90; and M. Szalay, “The San and the Colonization of the Cape 1770–1879”, in Research in Khoesan Studies, vol. 11 (Cologne, Rüdiger Köppe Verlag, 1995).

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Q News South Africa’s new HIV/AIDS plan In April 2007, the South African National AIDS Council, under the leadership of Deputy President Phumzile Mlambo Ncguka, endorsed the country’s new, sound, and comprehensive strategy for managing its AIDS epidemic. Drawn up after exhaustive consultations, and including groups that were previously snubbed, the new 160-page strategic plan is welcomed by parties as wideranging as government, the Congress of South African Trade Unions, the Treatment Action Campaign, and the United Nations. The plan acknowledges that South Africa’s mortality rates increased by 79% between 1997 and 2004, and that mortality in children under 5 years old rose from 65 to 75 deaths per 1 000 births in the years 1990–2006. But, with new partnerships, more innovation, decentralization away from hospitals, and a massive injection of funding, the crisis is not insurmountable. The strategy aims to cut infection rates, improve diagnosis, and treat the estimated 5.5 million South Africans already infected with HIV. Mlambo Ncguka announced government’s commitment of R14 billion over five years, and confirmed that the costs of the new plan will be high – about 20% of the health budget. Adult antiretroviral treatment (ART) will take up about 40% of the cost, followed by support of orphans and vulnerable children at 7%. Achieving the target of 80% of new AIDS cases on ART would cost R4.97 billion in 2007, and rise to R6.85 billion by 2011. The plan expresses the hope that the private sector and foreign donors will provide half of the cash, with the South African government paying the rest. The main goals of the new strategy are to: ■ reduce the number of new HIV infections by 50% by ensuring that South Africans who are negative remain so (targeting 15–24-year-olds in particular) ■ scale up coverage of prevention of mother-to-child transmission, to reduce it to less than 5% ■ reduce morbidity and mortality by providing adequate treatment,

care, and support to 80% of HIV-positive people and their families by 2011 ■ promote a national culture of voluntary testing and counselling, within and outside health services ■ overcome the lack of human resources by training and bringing on board less-qualified cadres (such as primary health-care nurses and lay counsellors) ■ set up partnerships between the public sector and civil society ■ improve monitoring and evaluation to measure the plan’s effectiveness. The plan is crucial for the country. A report released in November 2006 by the Actuarial Society of South Africa estimates that 1.8 million people have died of AIDS in South Africa so far. The number of people requiring antiretroviral drug treatment range between 800 000 and 1 million, but only about 300 000 are receiving it, with two-thirds of them being treated by the Department of Health and the rest by private healthcare schemes and NGOs. Only one-tenth of the estimated 200 000 children who could benefit from the treatment are receiving it, says the International Treatment Preparedness Coalition – partly because the treatment of children carries extra bureaucracy. Just to be tested for HIV (a prerequisite for accessing ART), they need identity numbers, which many don’t have, as well as consent from a biological parent (a problem if they’re being cared for by an extended family). For no other medical condition must such criteria be met before treatment is started. But things have to be made to improve. The advice of the Deputy President is as follows: “If you are [HIV] negative stay negative as your own personal fight. This is your biggest gift to Africa”, and, she adds, “Everyone and all of us should be an activist. There isn’t room to stay on the fence in this situation.” Sources: Nature (3 May 2007) and The Lancet (12 May 2007).

More IPCC reports on climate change On 6 April 2007, Working Group II of the Intergovernmental Panel on Climate Change (IPCC) released its summary report on climate-change impacts, adaptation, and vulnerability. The clear message from the 441 scientists who worked on this report is that climate change is affecting the world’s ecology. This is the first report to use observations of the Earth’s climate rather than predictions of possible future scenarios. Its prognosis is made on the basis of the current state of the climate system. Of the 29 000 datasets that were reviewed, 90% show that changes happening worldwide are due to climate change. The report details how different amounts of global warming (from no change to 5 °C on average) would affect human societies. It explicitly emphasizes that those most affected will be the world’s poorest – that is, those people who have done least to increase levels of greenhouse gases in the atmosphere. Here are some of the new predictions made, when this updated report is compared with the previous one of 2001. ■ Some 20–30% of animal species (those studied so far) could be at risk of extinction if global temperatures rise more than 1.5–2.5 °C. ■ Fisheries in large lakes in Africa could be adversely affected, not just by overfishing but also by rising water temperatures. ■ Glaciers melting in the Himalayas could reduce the amount of drinking water available to people, destabilize slopes, and lessen river runoff. ■ More drought and fire could put croplands and forests in southern and eastern Australia at risk. ■ Agricultural land in Latin America could turn to desert and grow saltier. ■ On small islands, invasive species could arrive sooner as temperatures rise. Further prognostications are that semi-arid low latitudes, such as

sub-Saharan Africa, will have reduced amounts of water available, and that even a 1 °C warming will diminish agricultural yields in such areas. They contain precisely those countries that tend to be relatively poor and ill-equipped to adapt to such changes. The harm that can be expected immediately, says the report, includes less food from farming in some regions, more violent storms, more drought and heatwaves, early flowering seasons, and changes in insect migrations. By 2020, between 75 million and 220 million Africans will suffer from increased water stress, and in the same period, in some African countries, yields from rain-fed agriculture could halve. What can be done? Recommendations include building dykes, developing genetically modified crops that can grow with less water, and cutting greenhouse gas emissions immediately. The final contribution to the IPCC fourth assessment report, from Working Group III, released in Bankok, Thailand, on 4 May, offers optimism about the possibility of mitigating climate change. The cost of cutting greenhouse gas emissions may not, after all, be as great as previously feared: policies that aim to limit human effects to the equivalent of a doubling of the carbon dioxide level compared with that at the start of the industrial revolution would cost about 3% of the world’s GDP by 2030, rising, by 2050, to 4% or 5%. While this constitutes large sums of money, the investment in the Earth’s future would lower the growth of the world’s economy by no more than 0.12% per year. Policies leading to further technological change could reduce these total costs, even though there are upfront expenses. The answers lie in political will and an emphasis on energy technologies. It has been remarkable and encouraging, say participating scientists, that governments have agreed to these 2007 reports to the extent that they have done. Perhaps there is hope for the planet after all. Sources: New Scientist (14 April 2007) and Nature (12 April & 10 May 2007).

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Farming fungi termites show the way It’s been known for a long time that some termites perform intensive agriculture – they cultivate mushrooms inside their nests. Duur Aanen and Wilhelm de Beer describe new research, which suggests that termite agriculture had its beginning in the rain forests of central Africa and spread later to savannas and to Asia.

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All photographs supplied by the authors, unless otherwise stated. Top: Close-up of a fragment of the fungus garden cultivated by a colony of the termite species Macrotermes bellicosus. Photograph: Karen Machielsen Above: A fragment of fungus garden.

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umans began to practise agriculture some 10 000 years ago, but cultivating your own food is not unique to people – a group of termites1 found in tropical Africa and Asia has been growing a fungus for food inside their nests2 for millions of years. The cooperation between termites and fungi is an impressive example of ‘mutualistic symbiosis’, that is, of natural cooperation and coexistence between two different species that is of advantage to both. In this case, the termites build nests that act like greenhouses, and go out in search of plant material with which to provision their fungus gardens. They offer their fungal symbionts finely broken down, usually dead, plant material, such as wood and dry grass, and the fungi grow on this substrate. In their turn, the fungi decompose carbonrich complex plant materials, such as cellulose and lignin – which the termites do not have the enzymes to digest

directly – forming nitrogen-rich fungal biomass that provides the termites with most of their food. A termite colony can consist of millions of sterile workers and soldiers, all descending from a single queen and a single king. Inside the termite nest, which can become very large, the fungus is grown on a fungus comb maintained by the workers. They constantly add new plant substrate, all the while consuming older fragments and asexual fruiting bodies (or nodules)3. The evolution of the symbiosis New research has been conducted, reconstructing the phylogenies (or evolutionary developments) of both partners in this symbiosis. It has shown that there was a single, dramatically innovative and irreversible transition to agriculture in this group of termites. In other words, the phylogenetic reconstructions show all fungus-growing termites descending from a single ancestor that ‘invented’ agriculture about

1. Termites used to be called ‘white ants’, even though they are not ants at all. 2. Ants are the other social insects, apart from termites, that, about 50 million years ago, learnt to cultivate fungi for food. 3. They eat the older fragments for food. The asexual fruiting bodies carry the spores of the fungus, which the termites redistribute to new parts of the substrate to speed up the cultivation process.


Above: Some of the different castes of Macrotermes natalensis: large soldiers, small soldiers, and workers. They are closing off holes in the side of a mound. Right (from top down): The central fungal chamber inside a nest of M. natalensis, about 80 cm beneath the ground surface. The fungus garden is distributed over small chambers, carefully maintained by a large worker force. The complete fungus garden of a medium-sized colony of M. natalensis, opened in a common effort by researchers in the grounds of the Plant Protection and Research Institute at Rietondale, Pretoria. The above-ground portion (which serves mainly as an air-conditioner) of a mound of the termite M. natalensis, in an open stretch of savanna grassland. Two Pierneef woodcut prints of termite mounds in Namibia. Courtesy of the Natural Cultural History Museum, Pretoria, both prints entitled “Miershoop S.W.A.

30 million years ago. These termites domesticated only a single fungal lineage, represented by the extant genus Termitomyces, and, in the millions of years that the symbiosis has existed, they have not domesticated any other fungi. Furthermore, once the symbiosis had been established, neither of the two parties ever reverted to a non-symbiotic lifestyle. To this day, they continue to depend upon one another.

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Colonizing success The symbiosis between fungus-growing termites and their fungi has a big impact on most African and Asiatic ecosystems. Although fungus-growing termites are also found in tropical rain forests, they flourish in savanna ecosystems, where their ecological impact is greatest. It has been estimated, for example, that fungus-growing termites are responsible for 90% of the decomposition of wood in some savanna areas in Kenya. The domesticated fungus, Termitomyces, is a so-called white-rot fungus. White-rot fungi are among the

few organisms that can degrade the plant material lignin, so they play an important role in the ecosystem’s carbon cycle. The optimal conditions for whiterot degradation are humidity combined with a constant and high temperature. These conditions are met in rain forests, but not normally in savannas. So how can white rot function in these environments? The answer is: through the extraordinary sophistication of termite farming. Inside a termite nest in the savanna environment, the conditions are very similar to those in the tropical rain forest, and the termites have developed highly advanced and flexible ventilation techniques to maintain constant rainforest conditions. Research in west Africa has shown, for instance, that outside temperatures can fluctuate by as much as 35 °C between winter nights and summer days, whereas within the termite nests, where the fungi are grown, the temperature always remains in the narrow range of 29–31 °C.

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Top: Fruiting bodies of Termitomyces reticulatus between the inconspicuous mounds constructed by the termite Odontotermes latericius. Middle: In many species of fungus grown by termites, the fungus regularly reproduces sexually via the formation of mushrooms. Here the mushrooms of T. reticulatus are growing straight out of the underground fungus gardens of the termite Odontotermes badius. Below: A fruiting body of Termitomyces sagittiformis. In the centre of the cap can be seen the hardened umbo (or small hump), which had bored upwards through the surface of the ground. Warning: Do not pick or eat any mushrooms that have not been identified by an expert or by a person who knows mushrooms well. Certain white-gilled mushrooms that look similar to Termitomyces are in fact poisonous to humans.

The air-conditioning techniques that the termites use depend on an air-flow design that keeps the conditions right for growing the fungus. In Namibia and northern South Africa, we have observed, for instance, that the tall, conical mounds built by some fungusgrowing termite species point north, at an angle that reduces as far as possible the absorption of heat from the sun4. From rain forest to savanna The termites’ efforts to maintain a ‘rain forest’ climate inside their nests can be explained by the new findings, which indicate that termite agriculture originated in Africa’s rain forests. Based on the distribution of the habitats and the areas where extant species of fungus-growing termites are found, phylogenetic trees were developed for the termites and the fungi so as to reconstruct their original habitat and geography. (This research involves comparing the DNA from fungi and termites to establish genetic relationships, and using the information to extrapolate back into the past.) The rain-forest origin of fungusgrowing termites is a remarkable finding, since extant species of fungusgrowing termites are mainly found in savanna ecosystems, where their success has been both ecological (with respect to their relative share of the processes of ecosystem decomposition) and evolutionary (with respect to the high number of species that has evolved)5. We believe that what enabled both partners to colonize the savannas were the agricultural habits and

4. If the conical mound were built vertically, a larger area of their northern surface would be exposed to the heat of the midday sun. Pointing northwards at an angle, towards the sun, the mounds are less exposed to heat on the northern side. This effect has to do with the fact that the termite mounds in Namibia and northern South Africa are far enough south of the equator for the angle to make a difference. Here is how it works. When a tall object is located on the equator, its shadow falls directly beneath it at midday. When that object is located further south (in the southern hemisphere), its shadow at midday falls in a southerly direction – the further south it is moved, the longer its shadow becomes. (In the northern hemisphere, the midday shadow falls in a northerly direction.) The angle at which the termites build their mounds seems to be the one that provides the greatest protection to the northern surface of their nests. (You can illustrate this principle by holding a pencil directly underneath a light to see how the shadow falls – if you then move the pencil south, you will see its shadow change in length and point away from the source of light.) 5. In southern Africa, there are more than 40 fungus-growing termite species, but only about 7 or 8 morphologically distinct fungal species are cultivated by them.

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innovations of the termites, and their need to maintain the symbiotic relationship between the fungi and the termites outside the rain forest. To survive in their new, very different savanna environment, the termites had to make sure that they could feed themselves by cultivating their fungi. This meant creating nests with special ‘greenhouse’ rain-forest conditions in which they could grow their crops, enabling the termites as well as the fungi to spread beyond the rain-forest regions. Today, both the agricultural termites and their crops succeed better in the savanna environment than do their closest non-agricultural relatives, which still flourish best in rain forests. Out of Africa Apart from their agricultural life style, fungus-growing termites are similar to humans in yet another way. Analyses of mitochondrial DNA in humans – which is transmitted only via the female line – have shown that humanity’s ancestral mother, the so-called ‘mitochondrial Eve’, lived in Africa. Similarly, analyses of the mitochondrial DNA of fungus-growing termites have shown that the ‘mitochondrial termite Eve’ was also African. And, just as humans subsequently migrated out of Africa, so also did fungus-growing termites migrate, colonizing Asia at least four times and Madagascar once. Partners and rivals Nowadays many biologists consider the phenomenon of symbiosis as ‘reciprocal exploitation’ rather than as the kind of cooperation in which both partners are of assistance for each other’s benefit. Both partners clearly benefit from the association in the world of fungi and the termites that grow them, but their needs are not always the same. An example of a conflict of interest is the use of mutually maintained resources for reproduction. Although each is 100% dependent on the other inside a colony, their reproduction – in by far most of the species – occurs independently. This means that both sides – from their own perspective – would have an interest in limiting the other’s reproduction. Humans benefit too! Humans have also benefited from the agricultural success of the fungusgrowing termites, as the fungi that these insects grow for food produce aboveground fruit in the form of mushrooms that are safe for people to eat.


The Termitomyces mushrooms grow from the underground fungus gardens (sometimes several metres deep) like closed umbrellas pushing up through the ground. Their toughened tips bore through soil that is often very hard and compacted, breaking through the surface. There the fruiting bodies open out to form a cap (pileus) with a diameter, in certain species, of up to one metre. These Termitomyces fruiting bodies are a delicacy in many regions in sub-Saharan Africa. One of the best known species is Termitomyces titanicus, the world’s largest edible mushroom, which is highly prized in countries such as Zambia and Tanzania. In northern Kwazulu-Natal, T. umkowaani mushrooms are often sold by the roadside in the rainy season when they fruit – the Zulu name is ikhowe. During the early 1990s, research was conducted at the University of Pretoria to determine the nutritional value of Termitomyces species. It was shown that T. umkowaani contains much higher levels of amino acids, such as methionine and cysteine, than are present in commercially cultivated mushrooms. This makes these mushrooms more nutritious than other

varieties and could serve as a good source of protein in the human diet. In spite of the most modern and sophisticated agricultural technologies available, however, no human being to date has been able successfully to cultivate a Termitomyces mushroom in a way that is economically viable. We shall need to conduct much more research before we can understand fully the technologies that the first mushroom breeders have been applying with great success for millions of years. ■ Research into the evolution and other aspects of the symbiosis between termites and fungi are ongoing under the guidance of geneticist Dr Duur Aanen from the University of Wageningen in the Netherlands. Collections in the field and initial laboratory work are conducted during extensive annual visits to South Africa, in collaboration with mycologist Wilhelm de Beer at the Forestry and Agricultural Research Institute at the University of Pretoria.

Top left: Not all Termitomyces species produce large mushrooms: here is a cluster of smaller fruiting bodies of most probably T. clypeatus. Top: A basket of T. reticulatus fruiting bodies, showing the long pseudorrhiza that grows from the underground fungal chamber all the way up to the soil surface, where the mushroom then opens. Above: Sliced and butter-fried T. reticulatus served on toast: a meal fit for royalty! The hand-printed Zambian cloth in the background, with the artist’s impression of a Termitomyces mushroom connected to the fungus comb, celebrates the interaction between the termites and their fungi.

For further details, read: Duur K. Aanen and Paul Eggleton, “Fungus-growing termites originated in African rain forest”, Current Biology, vol. 15 (2005), pp.851–855; Duur K. Aanen and Jacobus J. Boomsma, “Social-insect fungus farming”, Current Biology, vol. 16 (2006), pp.R1014–R1016; Henrik Hjarvard de Fine Licht et al., “Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis”, Molecular Ecology, vol. 15 (2006), pp.3131–3138; Albert Eicker and Gideon C.A. van der Westhuizen, ”Field Guide – Mushrooms of Southern Africa (Cape Town, Struik, 1996); Judith Korb, “Thermoregulation and ventilation of termite mounds”, Naturwissenschaften, vol. 90 (2003), pp.212–219; Gideon C.A. van der Westhuizen, and Albert Eicker, “Species of Termitomyces occurring in South Africa”, Mycological Research, vol. 94 (1990), pp.923–937; Wilhelm J. Botha and Albert Eicker, ”Nutritional value of Termitomyces mycelial protein and growth of mycelium on natural substrates”, Mycological Research, vol. 96 (1992), pp.350–354; and Eugène N. Marais, The Soul of the White Ant (Penguin, 1973).

Facts about termites In the past, termites were often called ‘white ants’, even though they are no relation to true ants. They are, in fact, closely related to cockroaches, so some people view them as ‘social cockroaches’. There are about 2 600 species of termites, represented by 7 families and 281 genera. They are cosmopolitan insects, but are geographically limited to warm regions. All termites are social. They live in large societies of closely related individuals. Reproduction in a termite society is normally limited to the socalled ‘royal couple’, consisting of a queen and a king, both of which live much longer than the other individuals in termite society – the workers and the soldiers. Workers and soldiers do not reproduce, but, instead, help their parents and brothers and sisters to reproduce. Apart from their social behaviour, termites are well known for their symbiotic relationship with a variety of other organisms, which help them to digest the plant materials they consume. All termites have intestinal bacteria, and most also support protozoa in their guts. Only a minority of termite species cultivate fungi. These fungus-growing termites belong to a single sub-family (Macrotermitinae) consisting of 11

Q Fact file genera and about 330 species. Fungus-growing termites are found only in Africa and Asia.

Above: A Macrotermes natalensis queen, taken out of the royal chamber. Above right: An opened ‘royal chamber’ of a colony of Macrotermes bellicosus, where the queen (the bloated individual in the centre) lives with the king (indicated by the arrow). The small individuals are workers, all produced by the queen. She can be described as an ‘egg battery’ as she can lay up to 30 000 eggs per day.

Quest 3(3) 2007 25


26 Quest 3(3) 2007


Quest 3(3) 2007 27


Books Q Right: The Drakensberg dwarf chameleon (Bradypodion dracomontanum), seldom more than 14 cm long, is mainly found on bushes in the Drakensberg alpine veld.

Chameleons & conservation Chameleons of Southern Africa. By Krystal Tolley and Marius Burger (Cape Town: Struik Publishers, 2007). ISBN 978 1 77007 375 3

C

Above: Juvenile common flap-necked chameleons (Chamaeleo dilepis), distinctively bright green in colour. This is one of the larger species in the region.

28 Quest 3(3) 2007

hameleons are a type of lizard that, with snakes, form one of the major reptile orders, the Squamata. Just 19 of the world’s 150–160 species of chameleon are currently recognized in southern Africa, but there could be as many as 25 when newly discovered undescribed species are investigated further. Chameleons of Southern Africa is a beautifully illustrated handbook on the species in our region – indispensable for anyone who has wondered about these extraordinary animals with their changing colours, their projectile tongues for catching prey, the powerful tails that curl up into impressive spirals, and the swivelling eyes that give them a nearly 360° view of their surroundings. The book has two sections. The first gives general information about chameleons; the second is a field guide, describing the species of southern Africa and where to find them. American-born Krystal Tolley has worked on chameleons since coming to South Africa in 2001. She has spent an average of about two months a year studying them in the field “and even more time in the DNA lab, uncovering the secrets of their evolution, relationships, and taxonomy.” The book came about “because so many people had so many questions about chameleons – how many babies do they have, how can you tell females and males apart, what do they eat” and because, “amazingly – there was no readily available book on the natural history of chameleons.” The greatest challenge was preparing the accounts of the individual species. Chameleon taxonomy has long been, and still is, in a state of flux and confusion, observes co-author Marius

Burger, and it’s tricky to identify some species on the basis of appearance. Specimens of a particular species at one locality can vary greatly, and some species look much like other, different species, he says. But genetic sequencing gives “an alternative perspective on who’s who in the chameleon world. Krystal is involved in this field, and she has unravelled some of the enigmas of our local chameleon fauna.” This volume incorporates all the recent taxonomic changes, so, although it’s intended for both amateurs and professionals, herpetologists will appreciate this revision of chameleon taxonomy as well as the pictures of poorly-known and new species. The images are especially remarkable because chameleons are so difficult to photograph. They’re photogenic, observes Burger, but they’re uncooperative models, always dodging the camera, with their eyes all over the place, seldom giving you the striking ‘eye-contact’ picture you’re after. In fact, it’s best to photograph them at night. In daytime, says Tolley, they constantly orientate themselves away from the camera or try to climb off the bush or hide behind leaves, and they tend to turn dark as a stress reaction to all the activity around them and lose their beautiful colours: “A ‘chameleon-wrangler’ is a huge help … someone to coax the chameleon back to your side of the stick, or to put it back on the branch when it tries to escape the paparazzi.” Writing the book took five months, recalls Tolley, but it’s based on “accumulated knowledge of years in the field observing chameleons, years in the lab learning about their biodiversity through


Q Books New book The Cigarette Century: the Rise, Fall, and Deadly Persistence of the Product that Defined America. By Allan M. Brandt. (Basic Books, 2007). ISBN 0 465 07047 7

DNA, and the expertise of colleagues.” Burger collated the existing museum literature and the authors’ personal distribution records (for the spot maps for each species), corresponded with other photographers to obtain the images they lacked, and “for the rest, it was editing and editing ….” Chameleons live in many habitats, from grasslands to deserts, forest canopies and forest floors, along coastlines, and even on the highest mountain slopes. Not easy to find at the best of times, they’re getting scarcer as more and more natural vegetation is removed to make way for shopping malls, golf courses, housing, and agriculture. Some chameleon species are highly sensitive to change, and decreasing numbers can lead to local extinctions. They need enough of the right

Top: The Namaqua chameleon (Chamaeleo namaquensis), often found walking across desert, sandy areas, and gravel plains. Above (left): A male (left) and female Furcifer minor, showing how much the sexes differ in appearance. Above (right): Tail of a Cape dwarf chameleon (Bradypodion pumilum) covered in well defined tubercles.

habitat to be able to survive, and can do so even in people’s gardens, provided no poisons are used against the insects they need for food, and provided the gardens are free of cats – the number one killers of chameleons in such environments. For Tolley, the book is more than a field guide; it’s also an introduction to the conservation of reptiles. Readers will find it accessible, interesting, and irresistibly beautiful. ■

How the public can help conservation Marius Burger invites the public to help with ongoing research and with reptile conservation in our part of the world, as anecdotal observations from the public can be very informative. You can contribute by participating in the Southern African Reptile Conservation Assessment (SARCA), a project of the South African National Biodiversity Institute (SANBI), which aims to revise the reptile Red Data Book by 2009. This project uses digital pictures sent in by the public to improve our knowledge of reptile distributions in southern Africa. The reptile pictures are presented on the web-based SARCA Virtual Museum (www.reptiles.sanbi.org or www.saherps.net), where they are identified and commented upon by a panel of herpetological experts. Says Burger: “Further new species might be discovered in this manner. We welcome you to assist by submitting your photos to a project that will ultimately serve to conserve our local reptile fauna.”

This book has been described as a model for engaged medical history. Observer turned activist, Harvard professor Allan Brandt traces the economics and social history of cigarettes in the past hundred years, and the corruption of science in dealing with the dangers to health. With the cigarette-rolling machines of a century or so ago came mass production and successful advertisers and marketers who sold modernity, status, and glamour with each pack. The working relations that developed between American and British tobacco companies set a model for today’s globalized economy. The dangers of smoking were recognized early – but luxury taxes brought lucrative revenues to the very governments that disapproved of it. Perhaps most pernicious, however, was the misuse of science in the interests of cigarette manufacturers. Brandt uncovers the strategy that allowed such corruption (and continues to foster it in other fields today, such as global warming and the fossil record, and wherever vested interests are challenged): as long as it’s possible to claim something as ‘unproven’, action can be postponed. Rather than denying health risks, the cigarette lobby argued that the risks were ‘unproven’ and that more research (often funded by interested parties) was needed. Then, research that identified carcinogens in cigarettes somehow remained unpublished. As the parallel rates of increases in cigarette sales and lung cancer during the century grew clearer, more science was always called for and statistical evidence was rejected as ‘insufficient’. By the mid-1900s, the cigarette symbolized all that was good, erotic, and attractive, bringing women and minorities into the net. Fifty years later, it had made an about-turn, now representing the addicted social outcast. The most recent rise in smoking among American youth, however, could partly be due to this image reversal, the very dangers attracting people for whom risk-taking is a way of confronting societal norms. Even as science and legal action have triumphed in demonstrating the dangers of cigarettes, clever marketing and manipulation of data remain another kind of danger to watch out for. Source: a review by Sander Gilman in The Lancet (12 May 2007).

Quest 3(3) 2007 29


Fact file Q

Comets

Comet McNaught, the Great Comet of 2007 Comet McNaught1 (designated C/2006 P1) was the brightest comet in over 40 years. It was discovered on 7 August 2006 by British-Australian astronomer Robert H. McNaught. It came closest to the Sun on 12 January 2007 at a distance of 0.17 AU2 (roughly half the distance of Mercury from the Sun), and was viewed from the space-based SOHO3 observatory from 12–16 January. Its closest approach to Earth was on 15 January at a distance of 0.82 AU. After passing the Sun, it became visible to the naked eye for observers in the southern hemisphere. Photographers were enthralled, as these images from Cape Town illustrate. For more on Comet McNaught visit http://en.wikipedia.org/wiki/comet_McNaught Clockwise (from top left): Bright at twilight. Photo: Lisa Crause The tail’s ‘striated’ structure as dust particles are driven off the nucleus by the Sun’s heat. Photo: Sue Lawrenson Behind the SAAO. Photo: Stephen Potter From Hout Bay. Photo: Sue Lawrenson From a hilltop near Durbanville. Photo: Janus Brink Remarkable tail. Photo: Stephen Potter

30 Quest 3(3) 2007


Q Fact file Exploring comets

Back to basics

Three scientific missions to investigate comets and their properties stand out in the research history of this field.

Omens in history

13–14 March 1986: After journeying eight months and nearly 150 million km, the European Space Agency’s spacecraft, Giotto, encountered and flew by Halley’s Comet, sending back remarkable images. This one (above) reveals the comet’s single nucleus. Its elongated shape was larger than expected (about 15 km long and 9 km across) and only a small fraction of it was found to be active. For more visit www.esa.int/SPECIALS/Rosetta/ SEM091nvgje_0.html. Image: European Space Agency

16–22 July 1994: The international Hubble Space Telescope collected imaging and spectroscopic data as Comet P/Shoemaker-Levy 9 collided with the planet Jupiter. It was the first collision of two Solar System bodies ever to be observed. The 21 fragments of the comet’s nucleus (with diameters estimated at up to 2 km) released dust all the way along the path to the gas giant. For more visit www2.jpl.nasa.gov/ sl9/hst15.html. Images: NASA

4 July 2005: NASA’s Deep Impact spacecraft plunged into the nucleus of Comet Tempel 1 – the first mission ever to hit a comet’s surface. The above image is a composite, revealing various surface features including smooth and rough areas, steep slopes or cliffs, and circular features that are probably impact craters. At its hottest point Tempel 1 was 329 K in the Sun and 260 K in the shade. For more visit http://deepimpact.umd.edu/results/ excavating.html. Image: NASA/JPL-Caltech/UM M.F. A’Hearn et al., Science 310, 258 (2005).

Comets have fascinated people for millennia. They were often connected with civil unrest. A bad omen for some, for others they brought blessings. In 1066, the appearance of what we now know to have been Halley’s Comet, for instance, spelt doom to the Saxons in England but victory to the invading Norman forces under William the Conqueror (his wife, Matilda, commemorated the occasion by commissioning the Bayeux Tapestry, which depicts the comet). Many other historical events were associated with comets, including the defeat of Troy, the death of Attila the Hun, and the fall of Constantinople. The 16th-century Danish astronomer, Tycho Brahe4, discovered that comets were not atmospheric phenomena. His observations showed that comets moved far beyond the orbit of the Moon, thus having no physical influence on people or Earth-based events.

Their properties In 1949, US astronomer Frank Whipple proposed his ‘dirty snowball’ theory of comets, according to which the nucleus comprised frozen gases mixed with dust1. His hypothesis was borne out in 1986, when the Giotto space probe flew past the nucleus of Halley’s Comet and proved him right. Comets are thought to be part of the icy debris left over from the formation of the outer planets of the Solar System. With the advent of modern space probes and orbiting observatories such as SOHO3, more and more comets are being discovered and researchers continue to examine them in greater detail. Above right: A comet’s three main components are the nucleus, the coma, and the tail. The nucleus comprises ice, rocks, and dust particles, and is seldom, if ever, seen. The coma is a cloud surrounding the nucleus, observed as the comet’s fuzzy head; as it approaches the Sun it heats up, releasing vapour and dust, and grows in size (it can reach a diameter of a million kilometres). The tail is formed when radiation pressure from the Sun pushes the coma away from the nucleus. Often two tails may be seen: one is a gas or ion tail (often blue in colour from the glowing gas molecules); the other is a dust tail, usually yellowish-white (reflecting the sunlight falling on it), with its shape depending on the mass and size of the particles it contains.

Direction of comet’s motion Nucleus

Gas tail

Sun Visible coma Hydrogen cloud Dust tail

Tail always points away from Sun

Sun Comet approaching sun

Right: The tail of a comet can reach a length of 10 million km or more, and its direction is determined by the comet’s position relative to the Sun, that is, always pointing away from it.

Orbits Astronomers know of more than 1 000 comets (of which about 120 have been observed at two or more returns). They are classified Conic Sections into two groups: periodic and non-periodic. Periodic comets have elliptical orbits and return to the Sun regularly. The time between each return is called the ‘period’ of the comet. If the period is less than 200 years, it is known as a shortperiod comet; if more than 200 years it is a long-period comet. (Some 85% of known comets are long-period comets.) Halley’s Comet – probably the best known of all – is a shortperiod comet with a period of about 76 years; so is Comet Encke, whose period of just 3.3 years is the shortest of all known comets. Cone Non-periodic comets have parabolic or hyperbolic orbits and pass round the Sun just once in their lifetimes, such as Comets Ikeya-Seki (1964) and Bennett (1970). The recent visitor Comet McNaught (2007) is also a non-periodic comet and will not be seen from Earth again. As they pass through the inner Solar System, comets can have their orbits altered by the gravitational influence of the planets, notably Jupiter. Comet Shoemaker-Levy 9, which hit Jupiter in 1994, was a spectacular example. – Case Rijsdijk

Circle Ellipse

Parabola

Above right: When one object orbits another (in the way the Earth orbits the Sun), their orbits are not circular but elliptical, as Johannes Kepler discovered in 1618. You can observe the different shapes of such orbits by taking sections of a cone as shown here (known as conic sections). A ‘cut’ made parallel to the base will form a circle. If the ‘cut’ is made at an angle to the base, the shape is elliptical – the greater the angle the ‘flatter’ is the ellipse. If the cone is ‘cut’ through the base, the shape is parabolic. In general, planetary orbits are not exactly circular but are elliptical: the Earth’s orbit around the Sun, for example, deviates from a true circle by about 3%. 1. For Comet McNaught see “News” in Quest, vol. 3 no. 2, p. 27, and for more about comets see “Pluto – when is a planet a planet?” by Case Rijsdijk, on p. 25 of the same issue. 2. AU is the symbol for astronomical unit, a unit of length where 1 AU = 149 597 870 km (the mean Earth–Sun distance). 3. The Solar and Heliospheric Observatory (SOHO) is a joint European Space Agency and NASA spacecraft, was launched in 1995 to observe the Sun, and has discovered over 500 comets. 4. Tycho Brahe (1546–1601) designed and constructed instruments that enabled him to plot accurately the positions of the planets, Sun, Moon, and stars.

Quest 3(3) 2007 31


Viewpoint Q

Putting it all together – integrating technologies for business applications It’s not enough just to ‘invest in high tech’, writes Bokkie Fourie. Making it add value as a business tool means linking different technologies in a goal-directed way to solve particular problems.

M

icrochip technology and the introduction of the microcomputer are probably two of the late 20th century’s most significant developments. The explosion of technological progress that followed led straight into the ‘digital era’ and the advent of the personal computer (PC). The Internet changed the world – and the world of business – forever. These technological developments in information retrieval and transmission became the catalyst for the birth of the global village and a ‘boundary-less’ market environment. With these innovations came ever fiercer competition. Lowering the barriers to entry for competitors has brought businesses under increased pressure in activities that include (but are not limited to) production, customer delivery, and optimal maintenance of equipment. As a result, business have been compelled to investigate ways to improve, maintain, and speed up their processes. In short, to be competitive, organizations must now be able rapidly to assimilate and act on information about their customers and their operating environments. This translates into a pressing need for ‘real-time data’.

data be collected and where should they be stored? How could the collected raw data be transformed into relevant business information? ■ Visualization. How could businesses see or ‘visualize’ the data so as to interrogate and interpret them for use in business processes? The answers lay in finding the right technologies to overcome each hurdle, and then to design ways to link them up as efficiently as possible, to provide integrated solutions. The phrase ‘telematics applications and solutions’ is applied specifically to the activity of monitoring and controlling remote and mobile assets in real time, that is, immediately as they happen. It is defined as ‘the integrated use of telecommunications and informatics, also known as ICT (information and communications technology)’ and, more specifically, ‘the science of sending, receiving, and storing information via telecommunication media.’

The answers lay in finding the right technologies and then linking them up as efficiently as possible.

Telematics solutions As businesses sought ways to optimize their performance by collecting and interpreting data better and faster, several hurdles had to be overcome. Among them were the following. ■ The wide-ranging areas to be covered. How could businesses collect the relevant data from a variety of remote sources of information? How could they get the data to a central point for interrogation and interpretation? ■ Communications. By what means could they transmit the data, especially to and from remote areas? What would be the cost of implementing and using devices (or ‘platforms’1) for communication? ■ Data management. How would the

32 Quest 3(3) 2007

Telematics solutions or applications typically consist of four major components: hardware, communications, data management, and visualization. For the most part, these components or their integrated applications are not part of an organization’s core business, so external expertise is often brought in to address specific needs and solve problems. A provider’s identikit Designing integrated (end-to-end) telematics applications requires unique combinations of knowledge and expertise.

To integrate the technology components for developing and implementing them, you have to hand exactly the right kind of knowledge and expertise. The knowledge requirement includes ■ a broad understanding of the components of telematics solutions and how they need to be integrated to deliver complete, customized solutions, as well as up-to-date knowledge of new developments in this rapidly changing field ■ the ability correctly and accurately to interpret the specific application requirements of individual businesses and their precise operating environments The expertise that’s needed includes ■ detailed technical understanding of the components and how they can link up or ‘interface’ to deliver integrated solutions to particular problems ■ the ability (and the supplier networks) to select and source the right technological components for each specific solution ■ project-management skills, from conceptual design through research and development to final implementation. Origin Solutions, for example, is an organization offering a ‘one-stop shop’ to customers, in that it can develop, manufacture, and implement telematics solutions from start to finish. Specially designed modular components offer customized applications with short lead times, which brings speedy implementation and keeps to a minimum the financial investment required. Telematics solutions apply in a wide range of industries – in agriculture, environment management, transport – in short, wherever monitoring and remote control are needed in real time. Security systems are a good example. Illegal access to a home or office or commercial storage area is picked up by movement sensors and triggers an alarm signal; this is immediately transmitted to a control centre, which then reacts with an appropriate and rapid response.

1. The technical term ‘platform’ implies the total wireless network offered by a service provider to enable users to transmit and receive data. Cellphone networks, for example, include towers, servers, and telephone exchanges to allow clients to make phone calls, surf the Internet in GPRS (General Packet Radio Service), and engage in other communication activities.


Satellite Network Cellphone

Origin Server

Client PC

Cellular Network

Data are collected from remote assets for monitoring and for control by means of an electronic interface. Data are then transmitted to and from the interface via a modem installed with the interface. They are sent and received to and from the interface modem and a central data repository by a combination of wireless and terrestrial communications networks (GPRS, satellite, Internet), depending on the geographic location of the remote assets. The data received are stored, processed, and maintained in a central repository (database server). From here, data are made available to users for interrogation and/or interpretation. Finally, information is translated into visually accessible forms of processed data through the use of PC-based software, Internet browsers, SMS, e-mail, and the like.

Telematics components Telematics solutions or applications typically consist of four major components.

1

Hardware Hardware is the equipment that is installed on or with the remote or mobile assets (for example, trucks or pumps). Typically it comprises an enclosure with a PCB (printed circuit board) and other components to perform three basic functions. i. Sensor interfacing. Sensors are the means by which information is collected from the assets (trucks, pumps, meters, and others) or by which specific functions are controlled. Collection of data and control of functions are achieved through different types of input and output (I/O) including digital (to switch on/off), analogue (to measure specific values), frequency (to count), and communications ports, such as serial ports or universal serial bus (USB) ports. ii. Data processing and command execution. The data collected from sensor inputs must be processed before they can be transmitted for user interpretation. In some cases, some form of ‘on-board intelligence’ is also required to control or manipulate the performance of equipment or assets. This intelligence can either be rules-based to execute specific commands automatically, based on sensor data received via the inputs (for example, “if the water-level in this dam goes below level X, start the pump”), or it can be directed by commands from a remote operator (for example, “change the level at which the pump must start from water-level X to the new water-level Y”). Microprocessor(s) on the PCB are used to interpret the data received and to make logical decisions to execute specific activities. iii. Data transfer. Data are transmitted to and from the hardware via a modem for the real-time monitoring and control of assets. The modem facilitates wireless data communications via satellite or GSM (Global System for Mobile Communications) or GPRS (General Packet Radio Service) communications platforms.

Communications The communications platform(s) are essential to telematics solutions, providing the means for real-time interaction between organizations and assets that may be in remote locations. The communications channel will typically be either satellite or GSM/GPRS. To use GSM/GPRS, network coverage by a cellular service provider is needed in the geographic area where the assets to be monitored are located or moving around. Where cellular network coverage is not available, satellite communications can be used through any of a number of service providers. In some cases, assets to be monitored are localized in a relatively small geographic area, which allows for radio communication among assets and/or base stations.

3

Data management Data are what telematics solutions deal with. There are two reasons for this. i. The data received and transmitted from and to assets are important to businesses, so their validity and completeness must be ensured at all times – and the data must be backed-up and archived without fail. ii. The raw data must be processed so that they can be presented as relevant (and important) business information. Organizations then use this information in various aspects of the business, including operations, logistics, finance, and maintenance.

4

Visualization Seeing or ‘visualizing’ the data is the ‘predominant’ component of telematics solutions, in the sense that, in most cases, it’s the only one with which users/clients interact. The interaction is normally by means of a graphic user interface (GUI) in the form of software applications (installed on the user’s computer) or web-based tools (via an Internet browser, such as Internet Explorer). Other forms of transmitting readable data can also include SMS, e-mail, and fax notifications.

the way it schedules, plans, and allocates resources. It also means that assets can be maintained proactively – by anticipating, for instance, when maintenance is needed rather than waiting for equipment to break down before anything is done about it. ■ Finances. Improved operations and efficient maintenance translate into bottomline savings and increased revenue.

■ Security. Remote, real-time access to equipment and other business assets allows organizations to react faster when security is at stake – to trespassing or hijackings, for example – and to reduce damage or loss. Some examples help to illustrate integrated solutions that bring clear and measurable gains. ▲ ▲

Benefits to business Businesses benefit in many ways from telematics solutions for monitoring and/or controlling their assets. ■ Operations and maintenance. Being able to monitor (and control) remote assets in real time improves the way in which a business works, as the immediatelyaccessible information allows it to fine-tune

2

Quest 3(3) 2007 33


Viewpoint Q

Transport – vehicle tracking and temperature monitoring Transport companies and their customers need continuous updates on the movement and progress of cargo. Satellite tracking is used for monitoring a vehicle’s odometer readings as well as its location. The odometer data help in planning efficient maintenance schedules for vehicles. Location data are needed for the logistics of fleet management. The control centre receiving information from a truck every 5 or 10 minutes can monitor its geographic position closely. When a load is crossing a border-post, for example, the transport company is immediately alerted to any delays and can keep the customer informed. The problem for a transport company taking perishable goods over long distances by truck – particularly in a hot climate such as ours in southern Africa – is to make sure that the temperature in the refrigeration units remains within a specific temperature band in the ‘cold chain’ (the term used for the ‘temperaturecontrolled supply chain’ covering the journey from the initial loading of cargo into the container to its arrival at its final destination). Bananas, for example, are transported at 10–18 °C. This is because consistent temperatures below 10° C result in the

blackening of the skins, which makes the product unattractive for selling to end users. Consistent temperatures higher than 18° C cause the fruit to ripen too quickly and reduce their shelf-life in the shops. Information is therefore needed about temperatures in the refrigeration units. Frozen goods must remain below –10° C whereas avocados must stay within the 4–10 °C temperature band.

A driver’s control pad (or interface) in the cab of his vehicle, used in fleet management.

The telematics design allows truck drivers to select pre-programmed temperature bands to suit the different products that they have to transport. The driver’s control pad (or interface) is installed in the cab of the truck. The driver selects a particular band for a refrigeration unit, and whenever the refrigerator’s temperature deviates beyond the specified temperature boundaries a message is transmitted to software in the client’s operations control centre. This real-time information allows action to be taken as soon as potential problems are spotted, so that the cargo can be delivered in good condition. Agriculture – pump and centre-pivot monitoring and control Farmers are feeling the pressure to produce high crop yields and to make their operations as efficient as possible. In the crucial area of irrigation, for instance, they need carefully to monitor and control

This screen alerts the control centre of a transport company to a ‘high alarm’ condition in one of its refrigeration containers. The temperature has been set at ‘temperature band 3’ to transport fruit such as apples, grapes, and peaches. This means that, to maintain the quality of the cargo, the temperature must not fall below –1 °C nor rise above 6 °C for any period lasting longer than about 1–1½ hours. In this instance, at the two monitoring points in the container, the temperature has risen to dangerous levels (14 °C and 8 °C, respectively). This early warning tells the transport company that the refrigeration unit needs urgent attention.

34 Quest 3(3) 2007

A remote-controlled irrigation system.

the watering of their crops, and to reduce losses that are due to vandalism or the theft of equipment. A telematics solution has addressed such problems by means of an MCU (modular control unit), which allows a farmer to monitor and control the operation of centre pivots and pumps from a distance, without being physically present, by using a cellphone and specially designed software. The MCU hardware is linked to (or ‘interfaced’) with pump and centrepivot high-voltage control panels with various functions. Centre pivots are irrigation-system control mechanisms used for watering in intensive crop farming as well as for dosing plants with the right nutrients and pesticides in the right quantities at the right times. This sensitive equipment needs to operate exactly as and when required. At distances of several kilometres, it is cumbersome for a farmer to switch equipment on and off manually and to keep making sure that the systems are working as they should. Telematics enables such operations to occur automatically, and for data from different locations to be provided in real time at a central point to enable constant monitoring. Pivots can be programmed to change direction, for instance, to be turned on and off, and to adjust their operations to suit changing rainfall and soil-moisture conditions. Pumps can be set to draw water from a borehole or a dam at particular times of day, and to turn themselves on or off when certain water levels are reached. Monitoring the electricity supply to such equipment can tell a farmer if it has broken down or if someone has tampered with it. Environmental monitoring – weather stations and waterresource management Telematics solutions enable scientists


Q News to monitor all kinds of environmental observation equipment located in geographically remote areas, and to gather and evaluate data without having to travel long distances. Sensors at weather stations transmit data on humidity, rainfall, temperatures, and wind direction and speed, which are collected at a central data repository and then analysed at a control centre. Water resource management and water utilities also benefit in different ways – dam levels are controlled and monitored from afar; river levels are continuously assessed and water flow calculated from the data gathered and transmitted; water quality is monitored for pH levels and electrical conductivity, particularly in areas affected by industry.

information, amongst other things, about a customer’s electricity consumption; and the power supply to a consumer can be turned on and off by remote control (when an account is opened or closed, for instance, or as a last-resort measure when bills have not been paid). All such monitoring and control is achieved by gathering data from each individual location by means of an electronic ‘interface’ that is able to interpret such data and respond automatically by means of pre-programmed commands. The information is then transmitted in real time to a central control facility for different uses. Thanks to telematics solutions, a utility can monitor the security of its equipment, for example, and respond appropriately to any signs of tampering. When power Utilities – electrical enclosure supplies are interrupted, problems in the monitoring and access control electricity grid can be identified and action Electrical utilities need data from many taken to restore power to affected areas sites at some distance from the control with the minimum of delay. Should a centre. They have to address three piece of equipment such as a meter fail, main kinds of problem: tampering and it can be replaced or fixed; if protective illegal access to electrical power; enclosures or cables are damaged unauthorized access to and become dangerous, equipment enclosures they can immediately be (such as enclosures for repaired. electrical meters); Automated meterTelematics and the monitoring reading transmitted of consumers’ solutions enable to a central electricity use data facility scientists … to (through metercan be aligned readings, for gather and evaluate electronically example) to with payments data without having make sure that made (in prepaid accounts and to travel long billing systems, payment processes for instance), giving distances. work efficiently. customers instant Telematics information about what solutions provide for credits they still have and electronic alarm systems, helping them to decide when access control, and realthey need to buy new credits. time meter readings. The appropriate hardware is installed in a steel enclosure and signals are transmitted to and from the control centre. The alarm is raised as soon as a power supply is interrupted or disconnected, for instance, or if anyone tries to access power illegally or tamper with equipment, or if the temperature suddenly rises above the safety threshold for the kind of electronic equipment being used (in the case of extreme summer temperatures, for example). To monitor and control access to equipment (such as electricity meters), information is loaded into the system, identifying people who are assigned such access in specified areas and at specified times. Meter-readings are fed back with

Road safety Don’t phone when you drive The message is clear – stay off the phone when you drive. Your chances of having an accident are twice as high as they are if you’re just chatting to a passenger. Suzanne McEvoy and colleagues at the George Institute for International Health in Sydney revealed two years ago that drivers talking on the phone are four times as likely to have a crash that lands them in hospital as drivers who aren’t – even if they’re using a hands-free model. A follow-up study (reported in Accident Analysis and Prevention) investigated the effects of distracting conversation on road safety. The team’s survey of 274 drivers in hospital after accidents, in Perth, Australia, sends out a warning. Driving with one passenger made an accident 38% more likely to happen, and two passengers increased the likelihood by a factor of 2.23. But those talking on the phone while driving, with no passengers at all, were 4.1 times as likely to crash. South Africans, beware – take care if you travel in a lift club – and never use the phone when you’re at the wheel. Reported in New Scientist (21 April 2007).

Bokkie Fourie is managing director of Origin Solutions, a company that provides telematics solutions across a wide range of industries and applications.

Young people at risk If you’re between 15 and 19 years old, your most likely cause of death at that age is a road-traffic accident, says a World Health Organization report, Youth and Road Safety, released in April 2007. It’s the second most likely cause of death in the five-year age bands of young people above and below 15 and 19 years, and the third most likely cause in children aged 5–9 years. Most of the victims are young men and boys, and men under the age of 25 years are almost three times as likely as women of the same age to die in a road accident. The problem is particularly bad in poorer countries. Each year, 1–2 million people around the world die on the road, and millions more are injured. Such accidents in low-income and middle-income countries cost an annual US$65–100 billion (which is more than the total annual development aid given to those countries) and the casualties are more likely to be pedestrians, cyclists or motor-cyclists, and passengers. For greater safety, pedestrians should wear bright or fluorescent clothing; motorcyclists should wear helmets; and drivers and passengers should wear safety-belts. All children from an early age should be taught about road safety; all adults at all times should set a good example.

For details, visit www.originsol.com

Reported in The Lancet (21 April 2007).

The broader lesson For businesses – and for society in its various activities – to benefit from the marvels of 21st-century technology, there are important lessons to learn from telematics solutions and applications. First, know exactly what you want to achieve; second, know exactly what technologies are needed to enable you to achieve your specific goals; and, finally, design and forge the links among the different components so that they can work together to serve you in the best possible way. ■

Quest 3(3) 2007 35


Visit the travelling Science Tunnel exhibition for a journey of scientific discovery and previously hidden worlds, advise the ArchiMeDes experts from Germany. And get into the habit of keeping up to date – check current exhibitions at your local museums and make a special point of visiting them.

Science Tunnel travels S cience Tunnel, the travelling multimedia science exhibition of Germany’s Max Planck Society1, has arrived in South Africa. Previously hosted in Tokyo, Singapore, and Shanghai, it’s now at Johannesburg’s Sci-Bono Discovery Centre until the end of July, taking visitors to the limits of knowledge across the natural sciences disciplines. Designed to inspire young people to explore frontier science and innovation in the fields of physics, chemistry, biology, astronomy, nanotechnology, biotechnology, and the environmental sciences, Science Tunnel invites South Africans to journey through the world of ‘Made in Germany’ cutting-edge science. It shows the connections between different aspects of scientific knowledge and how they affect our lives. Interactive exhibits, images, and video clips turn research into an adventure. Specially built to travel the world, the mounting of this huge exhibition is a logistical marvel. It is 1 000 square metres in area, with 14 tunnel elements, 30 exhibits, 20 multimedia stations, and loads of additional equipment, all designed and coordinated to be assembled in different locations. In addition, all the parts must be strong enough to withstand the stresses of transportation over long distances, as well as frequent setting-up and dismantling. Seven years ago, in the record time

The Science Tunnel in Tokyo, Japan (above) and in Ludwigshafen, Germany (right.). Images: www.archimedes.com

of just three months, it was designed and constructed by the mobile exhibition agency, ArchiMeDes, as the Max Planck Society’s contribution to World Expo 2000 in Hanover. The theme of ‘sustainable development’2 guided the Science Tunnel round the world, drawing more than two million visitors by the end of 2004. In 2005, the contents and technology were completely updated for a new series of international tours.

Focus on the cutting edge This futuristic exhibition focuses on the rapid development of modern science – the astonishing worlds that scientists have opened up, and the new opportunities and challenges they present. Its 12 thematic stations reveal the functions of microscopic elements of our world, such as atoms, molecules, cells, and tissues, through to the vast galaxy clusters of the Universe. With the help of an audio guide, visitors explore the components of the material world – the building blocks of life,

1. The Max-Planck-Gesellschaft or Max Planck Society (MPS) is Germany’s most significant organization for fundamental research and one of the world’s leading research bodies. Founded in 1948 (succeeding the Kaiser Wilhelm Society, founded in 1911), it was named after the German physicist Max Planck (1858–1947), who won the 1918 Nobel Prize for physics for his formulation of the quantum theory, one of the most important scientific achievements of the 20th century. The MPS maintains 78 institutes and research facilities in Germany and employs some 23 400 staff members, including 4 300 scientists and 10 900 student assistants, fellows of the International Max Planck Research Schools, doctoral students, postdoctoral students, research fellows, and visiting scientists. It has three further institutes abroad as well as several branches. The MPS’s aim is to be the pacesetter in cutting-edge research, so it focuses on innovative subjects in the natural and life sciences as well as in the human sciences, supplementing research conducted in Germany’s universities. For more, visit www.mpg.de 2. The unifying theme of the World Expo in Hanover in 2000 was sustainable development, dedicated to Agenda 21, a global plan of action that takes ecological, social, and economic issues into account.

36 Quest 3(3) 2007

what causes diseases, how the brain works, problems of human society, the future of the Earth's biosphere, and the mysteries of the cosmos. Interactive exhibits mean that visitors can actively observe and discover what scientists themselves explore.

Tonnes of modules Modularity is the guiding principle for a travelling mobile exhibition. We employed sections of the complex shape of the original Tunnel, which were already available. Their support structure gave the new construction its distinctive shape, with a dozen research modules, the entry area, and a module devoted to presenting the Max Planck Society. Every module is shaped by two arches and covered by what looks like a membrane, made of fabric, which stabilizes the module and at the same time provides a


Q The S&T Tourist

surface for video projections. To show off its stunning photographs, the new Tunnel has concave graphic surfaces, lit from behind, secured to the feet of each module. The illumination gives the graphic area of the entire module a swaying effect. Through separate text-boards on either side of vibrating lighted boxes, the exhibits ‘speak’ to their visitors in a language they understand – English, German, or Japanese, depending on the host country. This travelling exhibition is made up of many thousands of parts and weighs 25 tonnes. It needs to be dismantled easily and its prefabricated parts packed safely for transportation, so the building units are standardized for stacking in a way that takes up the minimum of space. At each stop, the entire structure has to be reassembled competently – to create the same stunning effects as on the very first occasion. The logistics are crucial, and even with more than five years of touring experience, each new visit is a fresh endeavour. It takes two huge transport trucks and a 40-tonne crane to load the components into two 19-m-long ocean-going containers

installations, graphic boards, information boards, and exhibits are packed in waterproof aluminium boxes. The new Tunnel’s sea journey from Bremerhaven to Yokohama took 30 days, travelling via Algeciras, the Suez Canal, the Red Sea, and Singapore, and covering more than 23 000 km. After its most recent stop in Brussels, the Tunnel left Rotterdam for Durban on 22 March, arrived at Sci-Bono on 3 May, and took 13 days to be assembled before its opening on 18 May. After its close at the end of July 2007, the exhibition crosses the Indian Ocean to Seoul, South Korea. ■

Top: Discovering the Nano Cosmos. Image: www.archimedes.com

Above: Science Tunnel in Dresden, Germany 2007. Image: Felix Brandl

for each voyage. Inside, the containers are specially fitted for strapping the Tunnel parts down securely. As further protection against stormy weather, all the media

ArchiMeDes has its offices in Berlin and Kassel in Germany. With its long experience of mobile exhibitions, it is the exhibitiondesign agency that conceived and realized the Science Tunnel. The Max Planck Society's Science Tunnel exhibition came to South Africa as a project of South Africa’s Department of Science and Technology and with the support of Germany’s Federal Ministry of Education and Research. It is open to visitors from 19 May to 29 July 2007 at the SciBono Discovery Centre, cnr Miriam Makeba/President Street, Newtown, Johannesburg. For details, phone (011) 639 8400 or visit www.sci-bono.co.za. For more about the Science Tunnel visit www.sciencetunnel.com; www.mpg.de and www.archi-me-des.com.

Science Tunnel The Science Tunnel first appeared at the World Expo 2000 in Hanover and then continued as a travelling exhibition. Following its German debut, it went to Beijing, Shanghai, Manchester, Hong Kong, and Thessalonika. Since 2005, when the exhibition was modernized, it has visited Ludwigshafen, Tokyo, Singapore, Shanghai, Dresden, and Brussels. After Johannesburg, it goes to South Korea and India. The Tunnel has twelve thematic ‘stations’ 1. On the way to the Big Bang: Why are the laws of nature the way they are? 2. Nano Cosmos: How can we systematically influence materials? 3. Building Blocks of Life: What is life? 4. From Gene to Organism: Which programmes control the development of life? 5. Architecture of the Mind: How does the brain work? 6. The World of Senses: What is consciousness? 7. Technologies for the Future: Can complex systems be measured? 8. From Data to Knowledge: How does complexity arise? 9. Global Challenges: What constitutes sustainable development? 10. Spaceship Earth: How can we preserve the Earth’s protective system? 11. Our Home in the Cosmos: How do stars and planets originate? 12. The Universe: How and when did the Universe come into existence? Through the many interactive exhibits, visitors discover science for themselves. Here are three examples. Chaotic double pendulum With a chaotic double pendulum, small causes have large results. Minimal changes to the starting conditions have an enormous influence on the swinging of the pendulums, which never execute the same movement. Precise calculation and prediction of pendulum movement is therefore impossible. How is this demonstrated in the exhibition? 1. Press the start button. The ten LEDs (light emitting diodes) light up, the countdown starts.

2. Move the inner arm of both pendulums to the position shown right. Make sure that the outer arm is still. Take a step back. 3. After the countdown, both pendulums begin to move. However precisely you positioned the arms, the movement of both pendulums will, after a small number of swings, become asynchronous. Cycle at the speed a of light This bicycle enables you to ride through ‘virtual’ Tübingen, a town in Germany, and to experience the way the world distorts at the speed of light. The speed of light of ‘virtual Tübingen’ is reduced to 30 km/h. Right: A visitor riding a bicycle ‘at the speed of light’. Images: www.archimedes.com

Hands-on protein viewer: ribosomes – the cell’s protein factory Ribosomes translate the genetic code into proteins. A cell can accommodate up to 50 000 of these ribosomes, which consume more than 80% of the cell’s energy. In this exhibit, the small sub-unit can be seen – the so-called 30S-ribosome. The workings of antibiotics and the prevention of protein synthesis can be researched with the help of such virtual representations.

Quest 3(3) 2007 37


Work in Aviation Adrian Meyer explores the career paths available in the world of flight.

Left and above: Flying fixed-wing aircraft.

F

lying is integral to modern life, vital for the global economy, and valued by the travelling public. It’s an industry worth billions. Africa is expected to experience a 200% growth in air transport by 2020, so it needs urgently to develop its civil aviation industry and bring on more pilots, maintenance engineers, and air traffic controllers. Career opportunities abound in these fields. Many kinds of aircraft enable people to rise into or travel across distances through the air. Apart from familiar commercial airliners, there are hot air balloons, heliumfilled dirigibles, small aeroplanes (fixedwing, propeller- and jet-driven), helicopters, rockets (that is, high-powered wingless vessels), and hovercraft (machines that travel above ground or water on a cushion of air). So the aviation industry of the 21st century needs many different kinds of specialist. Prepare early The rule of thumb is ‘the larger the plane, the larger the team’, and the foundation for careers in aviation is the study of mathematics, science, and geography from an early age. These subjects are the key starting point for any prospective aviator, as they help students to grasp the concepts and principles of flight. Start planning for career options in aviation while you are young (even as young as 14 years) and ensure that you have a firm understanding of these subjects. Varied career paths Above (middle and below): Research conducted at the CSIR wind tunnel helps to improve aircraft design. Photographs: Courtesy of the Council for Scientific and Industrial Research (CSIR)

38 Quest 3(3) 2007

Aircraft designers

Who takes part in aviation design?

■ Engineers of many different kinds, each with at least an undergraduate degree but some with postgraduate degrees too. They include the aerodynamicist and the chemical engineer; the aircraft conversion specialist (qualified in aviation principles and components); the design engineer and the weight and balance engineer (qualified in mechanical, civil, or aerospace engineering); the electronics engineer (qualified in electrical, mechanical, or aerospace engineering); the equipment engineer (with a background in mechanical, electrical, or systems engineering); and the structures engineer (with a foundation in mechanical engineering). ■ Mathematicians develop the mathematical formulae that engineers use in design and they help engineers to solve problems. Metallurgists (with degrees in chemistry, physics, or materials engineering) and physicists also play their part. Technical and safety personnel

For safety, several professions are crucial, for which university degrees are not necessary but for which you need high-school or technicalcollege mathematics and science. Here are some examples (in alphabetical order): an assembler; a computer specialist; a draughtsman/computer-assisted-design (CAD) operator; an electronics installation technician; a builder of models and mock-ups; a sheet-metal fabricator; a technical illustrator; a tool designer; a wind-tunnel technician. Other careers may require a degree in a technical field as well as years of technical experience. These include becoming: a meteorologist or other specialist in flight operations; a flight engineer, who monitors the in-flight operation of an aircraft’s engines and mechanical and electrical systems; a navigator, who plots a flight course, reports positions, and estimates arrival time; an aircraft maintenance inspector, technician, or engineer; an engineering or electronics or manufacturing inspector; a flight-safety research specialist or an air-crash investigator.


Q Careers in S&T Pilots

There are many kinds of pilot, each with a special role and a formal qualification. Flight instructors teach student pilots how to fly, and instruction includes flight-simulation training in which skills are checked in safe ground-based conditions. Air cargo pilots transport freight; airline captains are responsible for the safety of their passengers and cargo; co-pilots assist pilots in operating the flight controls, watch the instruments and weather, handle radio communications, and keep logs; corporate pilots fly aircraft owned by business or industrial firms for flying company executives to branch plants or business meetings; test pilots specialize in testing new technology. Helicopter pilots fly to areas that are inaccessible for fixed-wing aircraft; crop-spraying pilots work in agriculture; stunt pilots perform aerobatic manoeuvres to entertain observers on the ground while others fly skywriting aircraft that release chemicals to create words in the sky, or drag advertising banners. Many people fly for sport or recreation. An array of general services requires the work of pilots – for medical emergencies, police work, defence, nature conservation, vehicle traffic-control observation, for instance. Pilots conduct sightseeing tours, provide airtaxi services, fly news reporters to the world’s hotspots, and provide for people taking aerial photographs, fire-fighting, and conducting search and rescue operations. US Air Force flight instructor, Mike Glaccum, describes the skills people need for success in aviation: “Tenacity and stubbornness - the ability to pursue something they want badly. To reach a goal. Becoming a pilot [is] much more than just skills or the glory of it. I like to remember a joke about how to tell a new pilot from an old pilot. Both carry two bags, one marked experience, the other marked luck. The new pilot has a full luck bag but an empty experience bag. The old pilot has the two bags reversed!” Neil de Lange, general manager of the Aero Club of South Africa, distinguishes between the amateur and the professional pilot. The latter dedicates his or her life entirely to aviation, but for both, flying is a passion beyond any other, and circumstances are often the only cause for the difference. Support staff

Many careers support aviation – on board in aeroplanes (such as flight attendants) and on the ground (such as baggage handlers, or loadmasters who supervise the procedures relating to cargo). Security personnel play an increasingly important safety role. And reservations staff connect the services that aviation offers with the clients who need them. Aircraft maintenance is crucial, and requires staff with appropriate technical training based

Right: Activities at Wonderboom Airport. Below: The air traffic controller is a key member of the airport staff.

on solid high-school mathematics and science: specialist mechanics service aeroplanes and prepare them for flying; others maintain landing lights, beacons, and stand-by generators, or install, test, and repair aircraft instruments and radio and radar equipment. ■ The information for this article was compiled by Adrian Meyer, the Chief Executive Officer of the National Youth Development Trust, with input from the Aero Club of South Africa and Boeing International. For more, visit the Aviation and Aeronautics Career Guide at www.khake.com/page41.html. The Wikipedia online encyclopedia has more than 970 000 references on aviation-related careers. If you are interested in flying for sport and recreation, visit the Aero Club of South Africa at www.aeroclub.org.za. Visit www.nydt.org and www.aeronauts.co.za for more about their involvement with the National Youth Development Trust and its Aeronaut Program, which provides opportunities for those less privileged to experience the joys and opportunities of flight.

Above (middle): The best start is to learn to fly a microlight aircraft, and it's the most inexpensive way for students. Above: Designing models is a way to learn about aerodynamics.

Words of advice from Boeing Aviation is a complex and challenging discipline, says Rudolph Louw, Executive Director of Boeing International for Southern and Eastern Africa. The science, physics, mathematics, and engineering that enable us to design, develop, build, test, and fly heavier-than-air airplanes require dedication and hard work. Boeing, which is almost 100 years old, has a global task force of more than 150 000 people dedicated to this purpose. It collaborates globally with industry and with institutions of higher learning such as universities and dedicated research facilities. It is never too early to start preparing for a career in aerospace, whether to become a pilot, or do maintenance, or work in air traffic management, or conduct any of the other numerous functions that work together holistically to enable us all to fly in a safe, comfortable, and environmentally friendly fashion. Preparing for a career in aviation/space should start as soon as possible. Choosing appropriate subjects at school level such as mathematics and physics allows learners to shape their thinking processes at a young age, and thereby contributes to the development over time of skilled scientists, engineers, and technicians. The technology leaps that we see almost every day in aviation (such as those in the new Boeing 787 Dreamliner) are indications of the exciting challenges that aerospace holds.

Quest 3(3) 2007 39


Letters Q

Letters to Bees and trees

W

e want to congratulate you on your wonderful science magazine. We only ‘discovered’ it last year and since then we have been telling everybody about it. The orderly layout makes it easy to read and even the younger members of our family have no problem in following the text. This magazine must surely be the answer to many a parent’s prayer! The articles can be used for projects and discussions. Another important factor is the fact that it highlights different career directions for the schoolchildren who are not sure about their future line of study. My own daughter, who is in grade 7 this year, is now highly motivated to take scientific subjects when she goes to high school next year, and to follow a career in science or biology in future. We also appreciate the fact that we as readers don’t get smothered in advertisements. Actually, your advertisements make interesting reading as well and are an extension of the fact-giving atmosphere of the magazine as a whole. We honestly hope that many people, and especially many schools in this country, are subscribing to Quest because so many of the articles create awareness of nature – something all the people in this world should wake up to. Here is a request: please place a follow-up article in one of

the next issues (in the not too distant future!) about the problems that our bee population faces in South Africa. Their numbers are diminishing at an alarming rate. Radio RSG had a very interesting talk show about it a few weeks ago. One of the reasons given by an expert was that our ‘normal’ bees are being invaded by black bees. Where do these bees come from, what are they doing to the honey bees, what can we do to rescue our bees? Another reason mentioned was that their food source is getting scarce, partly because of the drought but also because many places are becoming ‘bee unfriendly’ – either through disappearing habitat or the misuse of insecticides. We would also like to know: has anyone done a study on the impact that the disappearance of invader plants such as the blue gum will have on nature, honey-badgers, and honey production, and thus the economy of South Africa? Since blue gum trees were declared ‘tree non grata’, these trees are being chopped down everywhere. But they are a major link in the food and honey circle for all our bees and honey-badgers! We wish Quest the best of luck in future and we are looking forward to the next issue. Ankie Malan, Tygerpoort

Invitation

W

e are learners from Solomon Mahlangu Secondary School, and members of the New Frontiers Science Club of Tshwane, Pretoria. We would like to challenge Science Clubs and learners from other schools in South Africa to participate with us in the first international interactive Space Law Competition. This competition will be in the form of a Junior Commission of Investigation. It will take place on 8 October 2007. Acting as legal counsel for various ‘clients’, participants will ‘investigate’ rights that apply under International Space Law. The legal issues that will be investigated are the rights of local government, a corporate business concern, and members of the public in the following scenario. n Spacecraft from two space agencies (NASA and the European Space Agency) have collided in space n Debris has fallen on various suburbs in Tshwane, the capital city of South Africa, and Cape Town n An electrical power plant, a water reservoir, some houses, and a number of cars were destroyed n Several people were injured.

The presentations of the learners who participate will be judged in an international video conference session by persons of standing in international space law, and the team with the best analysis in terms of international space law will receive an award. Learners who participate have to prepare their presentation on CD. We are going to participate with schools in the UK, and we are also expecting others to join in. The UK learners will represent the European Space Agency. We will represent clients in South Africa. Learners who are interested in our project and who would like to put up a team to represent one of the ‘clients’ in the scenario, or who want to find out more, can contact us by e-mail at newfrontiers@mweb.co.za or by fax at 0866 846 455. France Malatji (Team Leader), Solomon Mahlangu Secondary School, Mamelodi

Address your letters to the Editor and fax them to (011) 673 3683 or e-mail them to editor.quest@iafrica.com (Please keep letters as short as possible. We reserve the right to edit for length and clarity.)

News Q Discovery of a new Earth-like extrasolar planet On 24 April 2007, Stéphane Udry and colleagues at the Geneva Observatory announced their discovery of a planet, Gliese 581 c, in the ‘habitable zone’ of the red dwarf Gliese 581. Its low mass (about five times that of Earth), and its temperatures compatible with the presence of water in liquid form, mean it’s more like Earth than anything else we know beyond the Solar System*. Finding out whether Gliese 581 c is more like Earth than inhospitable Neptune means measuring its density, so astronomers are trying to observe the planet as it transits Gliese 581, in order to calculate its radius. This transit will be visible from our Solar System only if the observers are in the plane of the planet’s orbit, and the chances are a daunting 50 to 1 against. As soon as the planet’s existence was revealed, Harvard University’s

40 Quest 3(3) 2007

Dimitar Sasselov began observing the parent star, hoping to see it dim on 7 May. Failing to see a transit means waiting for new technologies for further exploration. Artificial radio transmissions also offer possibilities. The SETI (Search for Extra-Terrestrial Intelligence) Institute, California, listened (without success) for signals from Gliese 581 in 1995 and in 1997. But exoplanet hunter, David Charbonneau, is upbeat about the discovery of Gliese 581 c. He’s inferring that more such low-mass planets exist around dwarf stars and that it’s worth looking for them. Reported in Nature (3 May 2007). * For more about ways in which astronomers look for exoplanets see, “Finding extrasolar planets”, by John Menzies, in Quest, vol. 2, no. 4, pp. 30–33.


Q Q UEST crossword You’ll find most of the answers in our pages, so it helps to read the magazine before doing the puzzle.

You + Science = Planet Earth : A better place to live! At Stellenbosch University’s Faculty of AgriSciences you will learn how to apply your knowledge of science to the benefit of both people and the earth.

JEMIMA

Across 5 8

The main component of air and a soil nutrient (8) International observatory that observes the Sun (4)

Down 1/14 One thousand megabytes (4,4)

South Africa needs well-trained agricultural and forestry experts at all levels to supply our growing population with food and fibre, to ensure that food and food sources are unpolluted and safe, and that the environment is used and managed in ways that preserve it for posterity.

Job opportunities

2

A beetle larva (4)

There are wide-ranging and challenging job opportunities in agriculture and forestry, from the most practical to the most high-tech – outdoors, in laboratoria, or in business.

3

McNaught had one of these (4)

Agricultural and forestry education

4

An electrically charged particle (3)

Our degrees take three or four years to complete. After a bachelor’s degree, you can broaden your career opportunities through postgraduate study.

6

Classification of closely related species (5)

7

Beware! Some are poisonous (5)

9

The main constituent of plant-cell walls (9)

9

Primary ingredient of fossil fuels (6)

11

Termite mound shape (7)

13

Interdependency among species (9)

16

Metric unit of volume (5)

18

Used as identifiers for tracking (4)

10

A chameleon is a type of what? (7)

21

Recurring heavenly body (5)

12

22

See 25 Down

Descriptive of luxuriant vegetation (4)

24

Chip to recall data (6)

14

See 1 Down

26

Another name for the European sea eagle (4)

15

Methodical (10)

17

The D in DORIS (7)

28

The sky and some tails look like this (4)

19

Smallest particle of a chemical element (4)

29

The U in UHF (5)

20

The V in VHF (4)

30

Non-metallic yellow element (7)

23/31 Collided with Tempel 1 (4,6)

31

See 23 Down

25/22 Immediate (4,4) 27

A mixture of fat and flour used as a basis for making a sauce (4)

How do you like the crossword puzzle? Was this one too difficult? Too easy? Just right? Would you like more difficult puzzles as well (with prizes)? Or other kinds? Fax the Editor at (011) 673 3683 or e-mail your comments to editor.quest@iafrica.com (mark your message CROSSWORD COMMENT).

Admission requirements ● Matriculation exemption/endorsement ● 50% aggregate ● Natural Science or Biology SG: E ● Maths SG: D or HG: E

Exciting careers to consider after finishing your degree at Stellenbosch University ● Conservation ecologist ● Winemaker ● Forester ● Eco-tourism operator ● Entomologist ● Viticulturist ● Entrepreneur ● Community developer ● Animal or plant geneticist ● Horticulturist ● Wood processing specialist ● Quality controller

● Agricultural economist ● Researcher ● Environmental impact assessor ● Plant pathologist ● Extension officer ● Food scientist ● Animal scientist ● Soil scientist ● Consultant ● Water research manager ● Game ranch manager

Closing date for applications: 30 October 2007 Contact our Faculty Secretary (Leon Jordaan) at (021) 808 4833, fax (021) 808 3822, or e-mail agric@sun.ac.za for more information and visit http://www.sun.ac.za/agric


Diary of events Q Astronomy

applications for sustainable development to support the Plan of Implementation of the World Summit on Sustainable Development. For details and application form visit www.unoosa.org/oosa/SAP/act2007/graz/ index.html.

■ Iziko Planetarium, Cape Town Teenagers and adults can discover the diversity and magnificence of Dinosaurs, which once dominated the Earth (Mon–Fri at 14:00, excluding 4 & 25–29 June; Tues at 20:00 [and sky talk] excluding 26 June; Sat & Sun at 14:30). “The Sky Tonight”, a live lecture on the current night sky, is presented every weekend – you’ll receive a star map and be shown where to find the constellations and planets visible this month (Sat & Sun at 13:00). The school holiday programme for children includes The Twinkle Show, Davy and the Dinosaur, and the Dragon Workshop (numbers are limited, so check the dates and plan ahead.). For more

• The 2007 Robotics Olympics for school and university students is at the Tshwane University of Technology, 24–29 September 2007. • Prepare in advance for the 2007 World Space Week programme, which includes the 2007 Rocketry Olympics and attempts to set Africa records for bottle rockets, bottle rocket cars, and bottle rocket planes, 4–5 October 2007. • The first FAI-approved Space Modelling Rocketry event takes place on 6 October. For more information phone 083 339

• For the United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN SPIDER) newsletter visit www.unoosa. org/oosa/unspider/index.html; to join the subscriber list, visit www.ungiwg.org/cgi-bin/ mailman/listinfo/unspider. • For a calendar of upcoming conferences, meetings, and events relevant to the area of space-based solutions for disaster management and emergency response, visit www.google.com/calendar/embed?src=h1 a93vb3rk6ud1tvrequjsfk8s%40group.calendar. google.com

5135, fax 0866 846 455, or e-mail nydt@mweb.co.za

Competition

phone (021) 481 3900 or visit www.iziko.org.za.

■ South African Astronomical Observatory (SAAO) The standard tours at the SAAO are on the second Saturday in the month. Our open nights (on 9 & 14 July at 20:00, free of charge) include telescopes out on the grass through which to view the night sky, weather permitting. There are Youth Week activities for the Northern and Western Cape in mid-June. The Astro Quiz in mid-July is open to all schools interested in astronomy, with prizes to be won. For details of the SAAO tours in Observatory, Cape Town visit www.saao. ac.za/public. For Day and Night tours to SAAO Sutherland (booking is essential), phone (023) 571 2436 or fax (023) 571 1413 or e-mail karel@saao.ac.za. For more about the above events, phone Isobel Bassett, Senior Scientific Assistant, SAAO, at (021) 447 0025.

Space ■ Space School Africa 2007 The annual Lost in Space Survival Field Trip is in Moon Valley, the Richtersveld National Park, 9–14 July 2007.

42 Quest 3(3) 2007

International Science-Based Competition Entries close on 31 October for the following international New Frontiers Science Programme competitions: the International Future Problem Solving Competition; the International Space Settlement Design Contest; the Turkish Seagull ICT Projects; and the International Science and Technology Fair. Students selected to represent South Africa in the international competitions will be awarded South African colours. For more information phone 083 339 5135, fax 0866 846 455, or e-mail newfrontiers@mweb.co.za

News from abroad ■ Space The United Nations/Austria/European Space Agency Symposium on “Space Tools and Solutions for Monitoring the Atmosphere in Support of Sustainable Development ” will be held in Graz, Austria, 11–14 September 2007. It is concerned with the use of space

■ Spatial Data Are you interested in GIS, remote sensing, and data management issues in Africa? Access the Spatial Data Infrastructure (SDI) regional newsletter for Africa by visiting the Global Spatial Data Infrastructure (GSDI) Association on www.gsdi.org/newsletters; to sign up for the GSDI News List, go to www.gsdi.org/ newslist/gsdisubscribe.asp.

Conferences and workshops ■ International Workshop “Changements Climatiques et Adaptation en Afrique: Le Rôle des Technologies Spatiales”, in Algiers, Algeria, 25–27 June 2007. For details contact Abdelhaq Trache at trache@emi.ac.ma.

■ South African Institute of Physics (SAIP) Conference, first week in July 2007. For more contact Isobel Bassett, Senior Scientific Assistant, SAAO, at (021) 447 0025.

■ Fynbos Forum 2007, at Club Mykonos, South Africa, 1–3 August 2007. For details contact Wendy Paisley: tel. (021) 799 8824, fax (021) 761 5983, or e-mail at paisley@botanicalsociety.org.za.

■ 10th Annual SAASTEC Conference, “Science Centres and Sustainable Living – does your lifestyle cost the Earth?” hosted by the Port Elizabeth Museum, at the Pine Lodge Resort, Port Elizabeth, 28–30 November 2007. For details contact Karen Fish, PROfile PR Consultancy: tel. (035) 340 2409 or 082 320 0538, or e-mail Karen@profilepr.co.za.


Q ASSAf News

Wat er, wat er ever y where? Unfor t unat ely not!

T

he science academies of over 90 countries are members of an organization called the InterAcademy Panel (IAP) located at the Academy of Sciences of the Developing World (TWAS) in Trieste, Italy – part of what has come justly to be known as Italy’s gift to the developing world, the ‘Trieste system’. The IAP addresses important science-based issues through cooperative action, normally as a defined ‘Programme’. In each case, the national science academy of a particular country is called upon to be ‘lead academy’ for such a Programme. The Brazilian Academy of Sciences (BAS) is the lead academy of the IAP Water Programme, which sets out to link water research and management in developing areas of the world. The BAS requested the Academy of Science of South Africa (ASSAf) to host its third regional workshop for African science academies and specialized water research organizations. The closed workshop, jointly organized by ASSAf and the Water Research Commission, was held from 16–19 August 2006. It was attended by researchers sent by seven other African science academies as well as by South African specialists, and the Proceedings have now been published (available on the ASSAf website at www.assaf.org.za). Africa is large (covering 20% of the world’s land mass), and has astonishingly varied geological and climatological regions. Nature does not respect political boundaries, and many of the most extensive river and lake basins – over 80 in total – are shared by different countries. Managing them as a resource, from the point of view either of a single country or collectively, is thus complicated, in terms of water conservation and utilization, disaster management, and power generation, for example. African water systems are notoriously short of wetland components (only about 10% of

them have these valuable areas, which help to control floods, store water, and filter and decontaminate it). Many of the important basins have large dams, but dams are now seen to cause environmental problems, despite the clear advantages of ensuring long-term security of water supplies for irrigation, industry, and human consumption. Speakers at the workshop described the urgent need to bring researchers and water-resource managers closer together. Africa has 10% of the world’s renewable fresh water, and a similar share of the world’s population. Some countries with scarce water resources manage to supply water to most of their people; others with enormous stocks supply only a small proportion of their citizens. Availability, therefore, is not the only factor that determines supply in general, or, in particular, an equitable supply to rich and poor and to those living in urban and rural environments. The main focus hitherto has been on water quantity (hydrology) rather than on its quality. As urbanization proceeds faster than the development of infrastructure, pollution and contamination are becoming prime determinants of what water is in fact available to those who need it. Groundwater (dubbed ‘blue gold’) has also been neglected because of emphasis on surface water, which is more accessible. The workshop concentrated, first,

on the water research being conducted in the participating countries, and, second, on evolving cooperative mechanisms for managing the resource to everybody’s benefit. Remarkable differences in policies and practices were revealed, but the common thread in almost every country was a severe shortage of scientific and managerial capacity. Since the science is basically the same (with interesting variations), cooperation at the continental level seems absolutely essential, and, within a shared river or lake basin, mandatory. Water research is multidisciplinary: it spans physics, geology, and engineering at one end, through microbiology, botany, and agriculture, to social science and economics at the other. It also represents a fascinating example of ‘systems thinking’ linked to policy, in that an adequate and relevant information base has to be translated into testable models of supply and demand, taking in different sectors of society and the economy, in different places at different seasons, and with short and long timeframes. The workshop ended with the form of communal think-tank known as a ‘knowledge café’, where agreement was sought on key priorities for water research, for policy development, and for integration with other developmental agendas across Africa. If one considers current predictions that sub-Saharan Africa will suffer serious water shortages arising from climate change over the next few decades, the effective and efficient management of its water resources is likely to shift to the top of the agenda. A young person wanting to help to secure our common future in these circumstances would find water research, through any one of a number of disciplines, an inspiring choice. – Wieland Gevers NOTE: The ASSAf news item, “Diet, Nutrition, and HIV/AIDS” in QUEST, vol. 3, no. 2 (2007) on p. 47 was written by Wieland Gevers.

Quest 3(3) 2007 43


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44 Quest 3(3) 2007


Q Back page science Noteworthy ■ “Things that don't quite make sense can be our most valuable tools.” David Wilson, Director of the Museum of Jurassic Technology. ■ “It is perhaps a more fortunate destiny to have a taste for collecting shells than to be born a millionaire.” Robert Louis Stevenson (1850–1894), author. ■ “Science is facts; just as houses are made of stones, so is science made of facts; but a pile of stones is not a house and a collection of facts is not necessarily science.” Henri Poincaré (1854–1912), French scientist and author.

Reasons to be cheerful Edge magazine asked scientists and other thoughtful people what made them feel optimistic. Here are some of their replies. Adam Bly, editor of Seed magazine: “I am optimistic that science is recapturing the attention and imagination of world leaders …. Science has made a well-timed transition from a topic of peripheral interest … to one inextricably tied to issues of development, global health, innovation, competitiveness, and energy. Our new global science culture demands a new level of science literacy, for general populations and indeed for the leaders that govern them.” Physicist Lee Smolin: “How can I be optimistic without knowing what direction science will take? This is exactly the point. There are two kinds of optimism, the optimism of people who think they know the future and the optimism of people who believe the future will be more interesting and, if always imperfect, more wonderful than they can imagine. I am of the second kind.” US psychologist Sherry Turkle talked about the “importance of objects in the development of a love for science — a truth that is simple, intuitive, and easily overlooked. And it is cause for optimism because it offers a hopeful note as we face our national crisis in science education …. Science is fuelled by passion, a passion that often attaches to the world of objects .... Giving science its best chance means guiding children to objects they can love. Children will make intimate

connections, connections they need to construct on their own.”

Toy story The Science Museum in London “collects toys for many different reasons, including the materials they are made of, the exciting new technologies they use, and the stories they can tell about the changing societies we live in … When children play they create their own worlds, but their toys also reflect the adult world around them.”

Karoo treasure South Africa’s Karoo Basin is the subject of research by the Smithsonian National Museum of Natural History because of the area’s “unmatched record of evolving paleoenvironments during which changes in biodiversity occurred.” Scientist and curator Conrad Labandeira has been studying the presence or absence in the fossil record of insect damage to plants. He wants to know more about insect ecological diversity, but he’s using plant fossils as clues because they’re more numerous than insect fossils.

Dem bones Fresh fossils contain more DNA traces than fossils that have been stored in museums using standard methods of preservation. Newly excavated fossils yielded DNA about 46% of the time in recent research, and older fossils only 18% of the time. It is thought that in cold, dry conditions, genetic material can survive for around 100 000 years. (Daily Telegraph, 12 January 2007)

Mite be more to this Fossilized mites found in livestock dung may help reconstruct history by showing patterns of disease and trade trends among ancient civilizations. Scientists working in the Peruvian Andes were looking at lake sediments to study climate change, but noticed how the number of fossil mites in the soil corresponded with what they already knew about the rise and fall of the llama-keeping Incas. “It couldn’t have been better if we'd made it up,” researcher Mike Frogley told BBC News. “It was that good.”

Gone without trace Letters were always an important source of information for science historians, revealing the thought processes and characters of the scientists who wrote to each other as well as confirming facts and revealing people’s reactions to news. Now that scientists communicate mainly by email and enter information directly into databases instead of writing it into lab notebooks, how will future historians piece the story together? For one thing, electronic information may quickly become unreadable. American Institute of Physics historian Spencer Weart puts it like this: “We have paper from 2000 BC, but we can’t read the first e-mail ever sent. We have the data and the magnetic tape – but the format is lost.” (Physicsweb.org, January 2007)

Drifting off to sleep Two retired American astronauts, Marsha Ivins and Dan Barry, have described what it’s like to sleep in space: because of zero gravity, you just float and don’t have to worry about the arm that’s underneath you getting uncomfortable. But if you happen to like pillows and heavy blankets or tucking your knees up, you’re in trouble. If you want anything to stay in place, you have to strap it there. Ivins had to strap her head to her pillow, and Barry said one arm tended to float up and bump him in the face. When he got back to Earth, Barry said, it took a while to get used to the idea that he wasn’t about to crash into the ceiling of his bedroom! (National Public Radio website) Compiled by Ceridwen Answers to Crossword (page 41) ACROSS: 5 Nitrogen, 8 SOHO, 9 Carbon, 11 Conical, 13 Symbiosis, 16 Litre, 18 Tags, 21 Comet, 24 Memory, 26 Erne, 28 Blue, 29 Ultra, 30 Sulphur. DOWN: 1/14 Gigabyte, 2 Grub, 3 Coma, 4 Ion, 6 Genus, 7 Fungi, 9 Cellulose, 10 Reptile, 12 Lush, 15 Systematic, 17 Doppler, 19 Atom, 20 Very, 23/31 Deep Impact, 25/22 Real time, 27 Roux.

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Answer to QUEST Maths Puzzle no. 2 The number of days is 36. The winner is Clive Wilcocks from Edenvale. In this solution, A represents the daily consumption of the cow, B of the goat, and C of the goose. We assume that the animals eat the grass at a constant daily rate, the grass grows by a constant daily amount (D), and the quantity of grass at the beginning is G. When the cow and goat graze together, there is no grass left after 45 days. Therefore, G – 45 × (A + B – D) = 0, so A + B – D = G/45 = 4 × G/180. When the cow and the goose graze field together, no grass remains after 60 days. Therefore, G – 60 × (A + C – D) = 0, so A + C – D = G/60 = 3 × G/180.

When the cow grazes alone, no grass remains after 90 days. Therefore, G – 90 × (A – D) = 0, so A – D = G/90 = 2 × G/180. When the goat and the goose graze together, there is also no grass left after 90 days. Therefore, G – 90 × (B + C – D) = 0, so B + C – D = G/90 = 2 × G/180. From this follows: A = 3 × G/180; B = 2 × G/180; C = 1 × G/180; D = 1 × G/180. The following holds for the time t that the three animals can graze together: G – t × (A + B + C – D) = 0, so t = G/(A + B + C – D) = G/(3 × G/180 + 2 × G/180 + 1 × G/180 – 1 × G/180) = 36. The three animals can graze together for 36 days.

Quest 3(3) 2007 45


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