SCIENCE SCIENCE FOR FOR SOUTH SOUTH AFRICA AFRICA
iThemba LABS: accelerating protons Training to care: HIV counselling HIV prevention: male circumcision
ISSN 1729-830X ISSN 1729-830X
VOLUME 6 • NUMBER 4 • 2010 VOLUME 3 • NUMBER 2 • 2007 R29.95 R20
Coastal living: early modern humans at the coast Targeted intervention: taking aim at men
A C AACDAEDMEYM YO FO FS C I EI ENNCCEE OOFF SS O U TT HH AAFFRRI C I CA A SC OU
Do you want to be one of an elite group of scientists who work in the nuclear industry? Nuclear scientists develop knowledge, techniques, equipment or products related to modern nuclear physics or nuclear chemistry and apply this knowledge to solve problems in areas such as medicine, industry, agriculture and mining.
What does one need to become a nuclear scientist? There is lots of scope in South Africa to work in the nuclear industry. To follow a career in the nuclear industry you will need to do well at school in subjects such as physical science and mathematics. At university you have to enroll for a science degree, majoring in mathematics, physics or engineering. Many South African universities offer postgraduate courses in nuclear science at their science and engineering faculties.
Where do nuclear scientists work? They are employed by large organisations and institutions such as the Nuclear Energy Corporation of South Africa, Eskom, the Directorate of Radiation Safety of the Department of Health, the South African Bureau of Standards, physics departments at universities, large hospitals with medical physics departments, and iThemba LABS for Accelerator-Based Sciences. Nuclear scientists usually work in modern, well-equipped laboratories at these institutions.
iThemba LABS The iThemba Laboratory for Accelerator-Based Sciences is a research and development facility administered by the National Research Foundation. The activities include basic and applied research using particle beams; treatment of patients with cancer; and the supply of accelerator-produced radioactive isotopes for nuclear medicine and research. The staff at iThemba LABS include engineers (mechanical, electrical, software), accountants, medical physicists, chemists, experimental nuclear physicists, artisans (fitter-end-turners, carpenters, machinists, technicians, plumbers and painters) material scientists, dieticians, nurses, oncologists, radiographers, pharmacists, HR practitioners, science communicators, accelerator scientists, IT specialists, secretaries, librarians, security personnel, and many more.
What does a nuclear scientist do? The nature of the work depends on the facility at which the scientist is working and the courses he/she took at university.
Above: Working in iThemba LABS’ “clean room”. The production of radiopharmaceuticals involves a number of steps: bombarding the target material; a chemical process to “retrieve” the isotope of interest; conversion to the radiopharmaceutical which is ready for patient consumption. This happens in the clean room where the scientists adhere to current Good Manufacture Practice (cGMP). After this, a number of quality checks are done before theradiopharmaceutical is dispatched. Above right: The separated sector cyclotron at iThemba LABS.
For example…. Ntombizonke Kheswa Ntombizone, better known as Yuyu, works in the experimental nuclear physics group at iThemba LABS. She is responsible for manufacturing “target nuclei”, which can either be a very thin foil or gas. The thin films are produced by carefully rolling the material. “This is not as easy as it sounds,” says Yuyu. Yuyu studied at DUT (Durban University of Technology) for a BTech degree, majoring in Chemistry. After completing her degree in 2005, she joined iThemba LABS. She is currently enrolled for a Master’s degree in Physics at UWC (University of the Western Cape). Yuyu’s knowledge of chemistry, e.g. understanding the Periodic Table of Elements’ “friendly” elements, radioactive isotopes, “toxic” elements, boiling and melting points, oxidation and reduction helps her to produce the target nuclei. “I also get to play with cool toys such as an electron gun and a state-of-theart mass meter!” she says. Yuyu’s career has afforded her the opportunity to visit Japan, Canada, Germany, the USA and France. That’s right – science can take you places!
A day in the life of a proton: the iThemba tale Gillian Arendse At iThemba LABS, protons spend their day whooshing around accelerators, being separated into many of the different components that are used in the nuclear industry in South Africa. 8
The HIV epidemic – where are we now? QUEST looks at the latest global HIV statistics and asks questions about the epidemic.
Training to care Steven Whiting HIV counselling requires compassionate and skilled people. HIVSA has developed a course to provide the necessary training.
Cutting HIV transmission: male circumcision
Contents VOLUME 6 • NUMBER 4 • 2010
QUEST looks at how male circumcision is being used to reduce heterosexual men’s risk of acquiring HIV. 13
Exploring the depths Albrecht Götz, Sven Kerwath and Toufiek Samaai SAEON has a new way to explore the deep oceans – the NRF’s remotely operated vehicle.
Men: the neglected target QUEST looks at prevention for men-whohave-sex-with-men.
The spectre of ocean acidification Mike Lucas
Rising levels of atmospheric carbon dioxide are having a negative effect on much of our marine life.
Shellfish and colour: early modern humans at the coast Curtis Marean
Pinnacle Point provided a refuge for early modern humans during the last ice age, and provides crucial evidence pointing to an early seafood diet and symbolic thinking.
Beka Nxele The ‘savanna problem’ or paradox has serious consequences for many of our conservation and farming areas.
Bush encroachment in savanna ecosystems: a cause for concern in land-use management
Molecular techniques for genetic modification QUEST looks at how molecular biology is used in genetic modification of organisms.
TB Alliance launches first clinical trial of a novel TB drug regime Novel drugs are urgently needed for this devastating disease.
Mega cities SAASTA
Mega cities – how do we define them and what are their features?
Fact file Particle therapy – p. 7
Solving SALT’s image quality problems
Diary of events
SALT’s spherical mirrors were causing problems with the optical images it received. Local know-how fixed the problem.
Back page science • Mathematical puzzle
Quest 6(4) 2010 1
SCIENCE SCIENCE FOR FOR SOUTH SOUTH AFRICA AFRICA
iThemba LABS: accelerating protons Training to care: HIV counselling HIV prevention: male circumcision
ISSN 1729-830X ISSN 1729-830X
VOLUME 6 • NUMBER 4 • 2010 VOLUME 3 • NUMBER 2 • 2007 R29.95 R20
Coastal living: early modern humans at the coast Targeted intervention: taking aim at men
A C AACDAEDMEYM YO FO FS C I EI ENNCCEE OOFF SS O U TT HH AAFFRRI C I CA A SC OU
Images: iThemba LABS, SACP4, Health4Men, UNAIDS
SCIENCE FOR SOUTH AFRICA
Editor Dr Bridget Farham Editorial Board Roseanne Diab (University of KwaZulu-Natal) (Chair) Michael Cherry (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 Free State) Penny Vinjevold (Western Cape Department of Education) Correspondence and The Editor enquiries PO Box 663, Noordhoek 7979 Tel.: (021) 789 2331 Fax: (021) 789 2233 e-mail: firstname.lastname@example.org (For more information visit www.questinteractive.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: email@example.com Subscription enquiries Patrick Nemushungwa and back issues Tel.: (012) 349 6624 e-mail: Patrick@assaf.org.za Copyright © 2010 Academy of Science of South Africa
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Design and layout Creating Ripples Graphic Design Illustrations James Whitelaw Printing Paradigm
2 Quest 6(4) 2010
Advice to a young scientist
any of you reading this will have just finished your matric exams. I hope that most of you will be looking forward to starting at university next year – and – because you are reading QUEST – I hope that you will be starting a science degree. Some of you will be in your first year of a science degree, with all the challenges that university offers. ‘Science is more than a body of knowledge; it is a way of thinking.’ Carl Sagan, writing in the book A Demon-Haunted World. In the same book he went on to say, ‘We’ve arranged a global civilisation in which most crucial elements – transportation, communications, and all other industries; agriculture, medicine, education, entertainment, protecting the environment; and even the key democratic institutions of voting – profoundly depend on science and technology.’ And yet, pseudoscience abounds and with it a slide into superstition and darkness, in Sagan’s words, ‘… a demon-haunted world.’ So what advice would I give to young scientists? First, question everything. There is still much that science does not understand – how wonderful to be part of a discipline where the unkown is exciting and beckons you to into the pleasure of finding things out. Be analytical – if a newspaper article tells you that antioxidant supplements are ‘good for you’ look for the original science. In this case you will find that this supposition is a myth – and worse – one that is the basis for a billion dollar industry. Take your analytical approach into the rest of your life – don’t take anything at face value. Become a sceptic - a person who is ‘inclined to question or doubt accepted opinions’. This is not the same as being tired and cynical – scepticism is the basis of science and an essential part of scientific analysis. Learn to speak out in support of science. You will find pseudoscience all around you – explain the scientific method to your friends and family and help them understand how to be analytical about the myriad claims of pseudoscience. Accept criticism. ‘Valid criticism does you a favour.’ Carl Sagan again. Science constantly challenges, looks for contradictions or small and persistent errors, proposes alternative explanations and encourages heresy. Science gives its highest rewards to those who ‘convincingly disprove established beliefs’. Work hard. Science is not easy – the greatest scientific minds work at their disciplines. And above all, love your science and the intimate knowledge that you have of the world around you. Be passionate, be an advocate for science and you will contribute to the broader community in a unique way. Find more good science on www.questinteractive.co.za.
Bridget Farham Editor – QUEST: Science for South Africa 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 organising. (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: email@example.com or fax your communication to (021) 789 2233. Please give your full name and contact details. ■
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Accelerator inftrastructure at iThemba LABS. Image: iThemba LABS
The nuclear industry in South Africa is world class and covers all aspects of the science of nuclear physics, as Gillian Arendse shows us.
A day in the life of a proton: the iThemba tale i Themba LABS (laboratory for accelerator-based sciences and technologies) is a National Research Facility administered by the National Research Foundation, which is committed to unleashing South African potential through knowledge creation, innovation and human capacity building. The facility aims to be the leading African organisation for research, training and expertise within the field of experimental nuclear physics and applications. Our lives are shaped by our lived experiences; our ability to see, touch, smell, taste; the ability to experience; the opportunity to be amazed; the opportunity to ponder, to wonder, to think. So how do we address issues related to what we ‘cannot see’? Take the structure of matter. (See page 13, QUEST 6(3) for an explanation of the structure of an atom.) How do we know what we know? Physics is a discipline where complicated problems get broken into smaller chunks that can be examined through inductive reasoning, mathematical manipulation, and experimentation. This often relies on the availability of a probe, a target, and a detector. Insight gained from fundamental research often provides us with techniques and skills that can
A day in the life of a proton Allow me to introduce myself: I am a proton, that is, the nucleus of a hydrogen atom. I get produced in an ion source where the electron is removed from the hydrogen atom. I have a charge of +1. Being a charged particle is great as this allows me to be pushed and pulled by electric and magnetic fields. After being accelerated to an initial energy of 8 MeV, I get injected into the BIG machine at iThemba LABS – the separated sector cyclotron (SSC). The SSC has four separate magnet sectors with an overall diameter of 13 m. You may know that a charged particle moving in a magnetic field experiences a force, where the direction of the force is determined by application of the socalled right-hand rule.
The iThemba LABS.
Image: iThemba LABS
eV stands for electron volt, which is a common unit of energy in physics and is used in solid state, atomic, nuclear and particle physics. It is not an SI unit and its value is obtained experimentally. However, it is commonly used with the SI prefixes, milli-, kilo-, mega- and so on. The conversion is 1eV = 1.6-19 J.
The magnetic fields available in the cyclotron allow me to be accelerated in a circle. To understand how this works think about a golf club. All points on a golf club move in a circle
Inductive reasoning is the kind of reasoning that draws generalised conclucions from a collection of specific observations. It is one of the most important activities in science.
be applied for other purposes. iThemba LABS is a facility where we not only perform fundamental research, but also apply our knowledge and techniques to address issues in, for example, the health sciences.
Installation of the steering magnet.
Image: iThemba LABS
Quest 6(4) 2010 3
The iThemba grounds in Cape Town – it’s not only about nuclear physics.Image: iThemba LABS
The K600 spectrometer.
Image: iThemba LABS
The right-hand rule for force on a positive electric charge due to a magnetic field. The fingers point along particle’s velocity (v), then along the magnetic field (B) (they curl towards magnetic field). The thumb will then point in the direction of force. Part of the AFRODITE detector array with scattering chamber.
This diagram shows the building blocks of matter, which is made up of atoms and sub-atomic particles, such as the nucleus, nucleons and quarks.
4 Quest 6(4) 2010
during a typical golf swing. But, because the points are on different areas of the golf club, each point moves at a different speed although they all take the same time to complete the circular motion of the club during the swing. The head of the club moves the fastest and the longer the length of the club, the faster the head travels. This is more or less what happens to me. I pick up speed because the electric field ‘kicks’ me every time I come round the circle. Each time I increase my speed, the circle I cover is bigger – the trajectory or arc of the circle. The maximum energy to which I can be accelerated in the SSC is 200 MeV, which means that I am taken out of the beam when the circle’s radius is at its largest. At this energy, I am able to travel a distance comparable to four times around the Earth in one second – swoosh! My every movement is
Image: iThemba LABS
remotely controlled by operators sitting in a control room. Evacuated beam-lines are available to transport me to one of four end-stations, either the nuclear physics experimental area, the proton therapy vault, the neutron therapy vault, or radionuclide production. Let me tell you more about what happens in each area. Nuclear physics research In nuclear physics research protons are used mainly to bombard thin targets – thin so that the nuclei of the atoms in the target are easily hit by protons. The protons can interact with the target nuclei in a number of ways – we say there is a range of open reaction channels. Again, think of this in terms of something more familiar. These different reaction mechanisms are similar to the different outcomes in a game of billiards where the outcome depends on the speed at which the cue ball travels before the collision. For example, the (p,n)
Proton therapy vault used for positioning.
Image: iThemba LABS
Each patient is fitted with a specially moulded mask that shows exactly where the particle beam should be directed. Image: iThemba LABS
Particle therapy iThemba LABS is the only facility in the southern hemisphere that can offer both proton and neutron therapy as a treatment modality for cancer and some non-malignant conditions. Protons are used to treat arteriovenous malformations, meningiomas and acoustic neuromas, and neutrons are used to treat salivary gland tumours, large inoperable neck nodes, inoperable maxillary antral carcinomas and endometrial sarcomas. Neutrons have also been used to treat advanced breast cancer. As the protons are directed towards the tumour or condition, they do not lose energy uniformly along their path, but deposit most of their energy in the last 2 cm of their range. The position of this spike, known as the Bragg peak, in the dose-distribution curve can be adjusted by inserting Perspex into the path of the beam and so covering the whole tumour. Protons, in contrast to X-ray photons used in conventional radiotherapy which lose intensity as they penetrate but never get to zero, have a finite range beyond which there is no radiation. The maximum range of our beam in water is 24 cm. This proton beam can deliver the correct dose with sub-millimetre accuracy, making it ideal for treating tumours that are close to sensitive structures within the human body, typically in the head and neck regions. The neutrons needed for neutron therapy are produced in a (p,n) reaction by directing 66 MeV protons at a berylium (Be) target. The profile of the neutron beam is shaped by a multi-blade collimator to match the shape of the tumour being treated. The reaction mechanism through which neutrons interact with human tissue is very different to that
A CT scanner is used to ensure that the beams are directed correctly. Image: iThemba LABS
Bragg peak The Bragg peak is a peak on the Bragg curve, which shows the way in which ionising radiation loses energy when it travels through matter, such as human tissue. In protons, the peak occurs just before the particles come to rest. The way in which ionising radiation travels through matter was described by William Bragg in 1903. When a fast charged particle, such as a proton, moves through matter it ionises atoms of the material and deposits a dose along its path. The peak occurs because the interaction cross-section increases as the charged particle’s energy decreases. This effect is used particularly in the particle therapy of cancer, because it concentrates the effect of light ion beams on the tumour that is being treated, while minimising the effect on surrounding healthy tissue.
The dose produced by a native and by a modified proton beam in passing through tissue, compared with the absorption of a photon beam, which is used in conventional radiotherapy.
reaction can occur emitting neutrons – p stands for proton and n stands for neutron; you could think of this as a knockout reaction. In a (p,d) reaction, the proton ‘picks up’ a neutron from the target nucleus to form a deuteron (d). A deuteron is the combination of a proton and a neutron. One common further possibility is that the proton can interact with the target nucleus and give it some energy. This means that the kinetic (movement) energy of the proton is reduced – it has given some of its energy away. This is called an inelastic scattering reaction. One of our flagship research facilities for studying proton interactions with atomic nuclei is our K600 magnetic spectrometer. In the spectrometer the incident proton beam interacts with a thin foil containing the target nucleus of interest – which can be any one of a number of different elements. This happens in an evacuated target chamber, which means that the reaction takes place in a vacuum. Reaction products are emitted in a direction-dependent way in the type of reactions we are discussing – socalled direct reactions. The rest of the spectrometer, which is made up of bending and focusing magnets and an array of charged particle detectors, is moved to focus on products of the reaction of the proton with the nucleus that are emitted at a specific angle. This allows nuclear physicists to start to understand the characteristics of the particles that are ‘knocked out’ of the target nuclei. If the scientists change the detection angle in the spectrometer, they can see how this change affects the probability of affecting a particular energy level in the target nucleus, which helps us to understand some of the fundamentals of the structure of the atom and subatomic particles.
Quest 6(4) 2010 5
The gantry used for neutron therapy that allows the beam to be directed from any direction. The floor opens so that the gantry has 360° movement. Image: iThemba LABS
The The beam-splitter facility (magnetic and electrostatic channels) and beam-line fitted with quadrupole magnets.
The isotope production facility at iThemba LABS, showing clean rooms and hot cells for the production and processing of radiopharmaceuticals.
Image: iThemba LABS
Images: iThemba LABS
of photons used in conventional radiotherapy. The nuclear interactions needed cause huge amounts of energy to be deposited, which is very effective in killing cells, so neutrons are often used to treat tumours that are resistant to conventional treatment modalities. Radionuclide production Radioisotopes are produced through nuclear reactions between 66 MeV protons and various targets. iThemba LABS has recently increased its radioisotope production capacity by commissioning a beam-splitter facility. This facility, only the second in the world, allows the initial beam to be
6 Quest 6(4) 2010
split in two, so creating the possibility of irradiating two target stations simultaneously. iThemba LABS is the only laboratory in the world that produces 22Na positron source. The laboratory also produces 25% of the world’s demand for 82Sr. The isotopes with short halflives are supplied to local hospitals as radiopharmaceuticals needed for diagnostics, while the isotopes with longer half-lives are exported to 60 international clients as generators or radionuclides for industrial, medical and research applications. The radiopharmaceuticals include 67Ga, which is used for tumour localisation,
for studies of the thyroid, 18FFDG for glucose metabolic studies, 81Rb/81mKr for lung ventilation studies and 68Ge generators for the diagnosis of neuroendocrine tumours. Protons just like me have been accelerated, have collided with targets and the effects and products of our interactions have been observed at iThemba LABS for more than 20 years. The facility is a leader in the field of accelerator-based science on the African continent and in many aspects even a world player. ■ Gillian Arendse is a physicist by training and is now the communications officer for iThemba LABS.
Particle therapy I
n principle, any site in the body treated with conventional radiotherapy can be treated with protons. The physical characteristics of the proton beam will allow a markedly decreased dose to normal structures. Not only can malignancies be treated, but also a number of benign diseases. This includes functionally abnormal areas that can be safely ablated by protons for diseases such as seizures, Parkinsonâ€™s disease, arteriovenous (A-V) malformations, macular degeneration, and severe rheumatologic conditions. However, because these are benign diseases, the amount of toxicity that is acceptable is less than when treating a malignant disease. Protons could potentially decrease toxicity to normal tissues, limiting toxicity and allow an increased dose of radiation, improving local control. iThemba LABS has also used protons to treat meningiomas and acoustic neuromas, two types of brain tumour. Specific cancers of the head and neck may benefit particularly from proton therapy, such as cancers of the nose, the mouth, the minor salivary glands, nasal cavity and the paranasal sinuses. Additionally, in tumours of the mouth and related structures, it may be possible to decrease the dose that carries through to the brainstem and spinal cord substantially. There are side-effects with this treatment, specifically a dry mouth when treating head and neck cancers. However, although patients treated with proton therapy will still experience this, the later side-effects associated with radiation therapy are less. Protons are most likely to improve our ability to get adequate dose to difficult-totreat areas (i.e. base of skull), and this may be where the greatest benefit is seen. Because protons can significantly reduce the side-effects of treatment as noted above, studies on escalation of dose are ongoing. For many sites, increasing the dose of radiation therapy to the tumour may increase the ultimate cure rates. There are enormous opportunities for the combination of proton therapy with chemotherapy and radiation sensitisers. This, in fact, may be where the largest benefit for proton therapy may be seen with integration in the overall treatment plan. Because protons can spare normal tissues, many patients who were not previously considered treatable again with X-rays may be treated with protons. This may further increase the cure rates in some specific malignancies. The treatment of childhood tumours is an area where proton therapy may significantly reduce the acute and longterm complications associated with conventional radiation therapy. Paediatric cancer treatment has significantly improved
over the past few decades and now five-year overall survival is approximately 80%. However, the paediatric population is exquisitely sensitive to the effects of radiation therapy. In this group of patients, cure is not enough. Long-term sequelae including growth abnormalities, second malignancies, neurologic complications, reduced IQ, cardiac and pulmonary toxicities, and infertility may all be reduced with the use of proton therapy. Up to twothirds of patients will develop long-term toxicity, some of which will be fatal. Proton therapy can reduce the integral radiation dose two to three times compared with any type of photon-based therapy. It is proposed that, due to the decreased normal tissue dose, proton treatment will lead to the development of less secondary malignancies. The relative risk of secondary malignancies is higher in children. Children are approximately ten times more sensitive to radiation. Children are smaller with organs that are more compact, which may increase organ exposure to radiation. Children are more likely to have genetic defects which may make them more susceptible to developing secondary malignancies. Well-recognised side-effects of conventional photon irradiation of the brains of young children include neuropsychologic and intellectual deficits. The side-effects vary directly with the volume of brain tissue irradiated and the dose of radiation delivered. By decreasing both the volume and dose of radiation to normal brain tissue through the use of protons, these side-effects should be minimised.
Arteriovenous malformations An arteriovenous malformation is an abnormal connection between a vein and an artery. People are normally born with them, that is, they are congenital. Most cause no symptoms at all and are only discovered incidentally at autopsy. The most commonly known A-V malformations occur in the brain, where they may cause bleeds, sometimes massive bleeds known as haemorrhage, or epilepsy. However, they may occur anywhere in the body.
A micrograph of an A-V malformation in the brain. Image: Wikimedia commons
Macular degeneration Macular degeneration is an age-related disease of the retina that eventually causes blindness. It results in loss of vision in the centre of the visual field because this area of the retina is damaged.
Numbers of patients treated using protons at iThemba LABS between 1992 and 2010 Arteriovenous malformation Angioma Acoustic neuroma Pituitary adenoma Meningioma Brain tumour Brain metastasis Paranasal sinus tumour Skull base tumour Orbital & eye tumour Craniopharyngioma Head & neck tumour Prostate tumour Other Patient total
1992-2010 83 15 68 65 42 60 33 23 29 33 14 11 4 32 512
A photograph of the retina showing the damage that causes blindness. Image: Wikimedia commons
Quest 6(4) 2010 7
The HIV epidemic – where are we now? ‘Indeed, if we do not respond with urgency and resolve, we may well find our vision of a thriving nation slipping from our grasp’. These words from President Jacob Zuma – QUEST looks at the epidemic at the end of 2010.
n October 2009, President Jacob Zuma gave what has been called a landmark speech to the National Council of Provinces. He called for an end to denialism and launched a major movement to cut new HIV infections by half and to reach at least 80% access to antiretroviral therapy by 2011. Worldwide, there are an estimated 33.3 million people living with HIV and the numbers continue to rise. However, at least some of the rise in numbers reflects the numbers of people living with HIV – actually living rather than dying – because they are on antiretroviral treatment. Sadly though, another factor in this rise is new infections. Globally, the spread of HIV probably peaked in 1997, when 3.7 million new HIV infections occcured. In 2009, the estimated number of new HIV
8 Quest 6(4) 2010
infections was 2.6 million. The epidemic seems to be stable in many regions, although prevalence is still increasing in Eastern Europe and Central Asia, due to a high rate of new HIV infections. Sub-Saharan Africa is still the most affected region, accounting for 71% of new HIV infections in 2009. There is also a resurgence of HIV among men who have sex with men in high-income countries. The estimated number of AIDSrelated deaths has probably also stabilised – it peaked in 2004. The estimated number of AIDS-related deaths in 2009 was 1.8 million. Sub-Saharan Africa The epidemic continues to have enormous impact on households, communities, businesses, public services and national economies in this region. However, there is a rapid scaling-up of antiretroviral coverage in sub-Saharan Africa, which is generating measurable public health gains. But there is no room for complacency – the epidemic is still outpacing the response. We need to continue to elevate the priority given to HIV prevention and match prevention strategies with actual needs. South Africa has recently been ranked as 138 out of 139 in terms of the business impact of HIV and AIDS in the Global Competitiveness Report issued by the World Economic Forum
(WEF), showing that the epidemic is still having serious effects on our country. In practice With the new statistics suggesting that the epidemic has stabilised in many regions, surely we can think that we are doing the right thing and should carry on in the same way? But there are still an estimated five people becoming infected for every two put on antiretroviral treatment, so it is clear that the prevention messages that may have worked at the beginning of the epidemic are no longer having the same effect. The structure of the epidemic is evolving – so must our response. One way in which scientists are doing this is to use data that follow the source of new infections or models of transmission and then basing HIV prevention programmes on what they find. In Lesotho, for example, there are nearly 60 new infections each day – and Lesotho is a small country. Adult HIV prevalence in Lesotho is more than 23% and both men and women start having sex at an early age. Based simply on these statistics you may think that the target population for prevention messages is all adults in Lesotho. However, research has found that one-third of all new infections occurred among people with a single sexual partner, while nearly two-thirds occurred in those who had multiple
partners. In addition, a third of all couples in the country include one partner who is living with HIV. But there are few behaviour and social change campaigns targeted towards adults, married couples and people in long-term steady relationships. A similar pattern was found in Swaziland. In Kenya, most new infections occur in people who have casual sex with multiple partners and among their monogamous partners. However, sex workers, men who have sex with men (MSM), prisoners and injecting drug users together account for nearly 31% of all new infections. In Mozambique, the figure for similar groups was 27%. Other aspects that should be taken into account are underlying cultural and socioeconomic factors such as power differentials in intimate relationships, sexual entitlements, cultural expectations of men and women and income inequality. In Lesotho and other African countries, young women continue to have relationships with older men, which contributes to the particularly high HIV prevalence among women. Violence against women and girls is another issue that needs to be addressed as part of HIV prevention programmes. Recent studies in southern Africa have shown that sexual violence towards women is alarmingly prevalent and, even more worrying, seems to be accepted.
Caring individuals are a vital part of the response to HIV and AIDS. Steven Whiting explains how HIVSA developed a counselling qualification for those who are intimately involved with the pandemic.
he HIV pandemic has had farreaching consequences for individuals living in South Africa. The country has the highest HIV infection rate in the world and proper access to treatment has only been possible in the last few years. The virus does not discriminate against race, age, socioeconomic status, gender or sexual preference. It is the brutal nature of the virus and the devastating effects of an apartheid regime that have made it difficult for the country to curb the spread of the virus. The success of South Africa’s HIV programme is largely dependent on the individuals that work hard at both a prevention and treatment level. These individuals not only comprise the professional medical personnel based at clinics and provincial hospitals but also the thousands of volunteers who devote their time and energy to the programme. These volunteers take on the roles of community care workers, peer educators, health promoters and counsellors. Some have entered the HIV arena because they were previously unemployed and needed the stipend paid by Government, others have lost loved ones to the pandemic or are themselves infected or affected in some way and then we have a huge majority who have lived through the devastating effects of the virus and strongly believe that something has to be done either through door to door campaigns, educational workshops, support
groups or counselling. HIVSA, like many other stakeholders, has recognised the valuable role these special individuals, specifically the counsellors, play in the fight against HIV. The current situation for counsellors in South Africa is that some are fully employed by NGOs and the state, but a huge number ‘work’ as volunteers and receive a stipend of R1 500 from government for their contribution at clinics and hospitals. This stipend unfortunately is not guaranteed on a month to month basis and this year the counsellors were not paid for four to five consecutive months. Yet despite this the counsellors continued to arrive at their sites, having begged and borrowed money from loved ones and friends to do the work they have come to love. At many health sites, the counsellors are the first point of contact for individuals deciding to have an HIV test and hence the quality of that interaction determines a number of outcomes for that very individual. First, that interaction will determine whether the individual will proceed with the HIV test. Second, if the test yields a negative result, the quality of counselling will influence the individual’s decision to remain negative by not engaging in risky sexual practices. Third, if the test results indicate that the individual is HIV positive, effective counselling ensures that the individual will take the necessary precautions to prevent the infection of his/her sexual ▲ ▲
New approaches to prevention We need new approaches to prevention and the rest of the articles in this section on HIV and AIDS look at two different approaches. One is adult male circumcision – which seems from many studies to reduce the risk of transmission of HIV. The other articles focus on men who have sex with men – where the prevention messages coming from researchers who focus on this area are very different from the norm. ■
Training to care
Quest 6(4) 2010 9
partner/s and live a healthy and fulfilling life. Finally and probably most importantly, if he or she needs to be on antiretroviral treatment, the nature of the counselling received will determine his or her adherence to treatment, the lack of which can have devastating effects. It is because of this need for qualitative and effective counselling that HIVSA became accredited to provide the Further Education and Training Certificate in Counselling. The programme began in February this year and 250 counsellors have been enrolled. Some of these counsellors are employed by other US President’s Emergency Plan for AIDS Relief (PEPFAR) partners, while the majority of the counsellors receive a monthly stipend from the Department of Health. The overall aim of the qualification is to equip the counsellors with the knowledge and skills required to provide HIV counselling. This includes pre and post HIV test counselling, adherence counselling, facilitating support groups, couple counselling and knowledge on dread diseases. The response from the counsellors has been immense. For many, this course provides them with an opportunity to fulfil their dreams of studying further, something they consider a luxury and a privilege. For others, the qualification is seen as a means of improving their skills as counsellors so that they can truly make a difference in the lives of the clients they see daily. Overall though, the qualification has provided education about aspects of life that they did not know about or had misconceptions about. For example, after having completed the module on Rights and Ethics, some counsellors reported that they did not know that the elderly had rights or that there was a difference between an illegal immigrant and a refugee. Counsellors report daily that the information they have acquired
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in the past nine months has ‘opened their eyes and minds’ about life in general and how different aspects interrelate. In a recent survey, trainers have reported an improvement in the counsellors’ level of knowledge and skill, with an overall change in perception around sex and sexual behaviour. Counsellor mentors have also reported an improvement in the counsellors’ behaviour, saying that there is a sense of professionalism among the counsellors. The qualification will continue until August next year and all counsellors who are found to be competent according to SAQA standards will be awarded Further Education and Training Certificates in Counselling. However, the greatest challenge that remains for many is lack of commitment from government regarding employment. The lack of representation by a trade union and the absence of an affiliation to a professional board mean that the counsellors fight this battle alone with some support from NGOs like HIVSA. Despite this, for many of the counsellors the recognition and acknowledgement received from HIVSA by being given the opportunity to complete a qualification is reward enough. About HIVSA HIVSA was established in March 2002 and has since emerged as an organisation that has made its mark in developing and implementing a range of psychosocial support programmes directed at households both directly and indirectly affected by HIV and AIDS. The organisation was formulated in pretreatment times, when it was acknowledged that psychosocial support, providing factual HIV information and educating people about the importance of nutrition and health lifestyles were vital parts of the response to the devastating effects of the virus. ■ Steven Whiting is the founder and CEO of HIVSA.
A carving clearly showing the circumcision procedure taking place in ancient Egypt. Image: Wikimedia commmons
The Bophele Pele Male Circumcision Centre at Orange Farm.
Image: Anova Health
Cutting HIV transmission: male circumcision It seems that adult male circumcision is a definite way to reduce the acquisition of HIV among most groups of men. QUEST takes a look.
he idea that male circumcision may help to prevent the spread of HIV infection was first put forward as long ago as 1986. When scientists started looking at rates of circumcision in sub-Saharan Africa it seemed as though there was a trend towards higher rates of HIV infection in areas with a low prevalence of male circumcision. This was mirrored across 118 developing countries. When researchers started to look even more closely at studies that had been done comparing rates of HIV in men who had and had not been circumcised it started to look as though male circumcision could indeed reduce the rate of infection. Male circumcision is one of the oldest and most common surgical procedures. It is practised for religious, social and medical reasons. Globally, 30 – 40% of men are circumcised, most of them Muslim or Jewish. In Africa, male circumcision has been in place for centuries, shown in carvings and murals in ancient Egypt. Across much of east and southern Africa it is a rite of passage for young men before they are considered adults.
The trials Simply looking at the distribution of male circumcision and levels of HIV infection was not enough to find out whether or not there was a causal relationship, in other words, whether it was the fact that a man was circumcised that reduced his chances of becoming infected with HIV or if there were other factors involved. To look at this relationship three randomised controlled trials were set up in Uganda, Kenya and South Africa between 2002 and 2003. Each of these trials was stopped early when analysis of the results showed that the men who were circumcised had a significantly lower rate of HIV infection than those who were not circumcised. A trial in South Africa in 2005 showed that circumcised men were 60% less likely to be infected with HIV than uncircumcised men. Similar trials in Kisumu, Kenya and Rakai, Uganda, showed 53% and 48%
Community outreach for male medical circumcision. Image: Anova Health
reductions, respectively, in the rate of HIV infection in circumcised men. A model based on the South African study estimated that male circumcision could prevent two million new HIV infections and 300 000 HIV-related deaths over ten years in sub-Saharan Africa. Turning research into practice As a result of these trials, the World Health Organisation (WHO) and the Joint United Nations Programme on AIDS (UNAIDS) now recommend that adult male circumcision programmes should be rolled out wherever there is a generalised HIV epidemic and few men are circumcised. They have also defined a minimum package of adult male circumcision services and have provided guidelines and tools that are designed to ensure that communities are involved in the roll out, that participants get the correct counselling and that suitable surgical facilities are available. ▲ ▲
Why should circumcision prevent HIV infection? There are several biological mechanisms that could explain how male circumcision may prevent HIV infection. The first is that the foreskin contains cells that may be particularly vulnerable to HIV infection, so removing the foreskin removes these
cells. Once the foreskin is removed, the underlying skin becomes thicker, which may make it more difficult for the virus to penetrate the area. There may also be a link between removing the foreskin and preventing other sexually transmitted infections. These infections often cause ulcers that make it easier for HIV to penetrate, so preventing them could reduce the rate of HIV transmission. Sexual activity may also cause tears, grazes or cuts in the foreskin that would make it easier for HIV to penetrate and so removing the foreskin removes this risk.
Quest 6(4) 2010 11
Men waiting in front of the Bophele Pele Clinic for their turn to be circumcised. Image: Anova Health
One of the doctors at Orange Farm enters the cubicle to perform a circumcision. Image: Anova Health
But there is often a problem with recommendations and guidelines that are based on academic clinical trials. Can the guidelines be translated into a real-life situation? A study in South Africa, the Bophele Pele (Health First) project in Orange Farm, was used to try the guidelines out. The project offers free, safe, adult male circumcision to all men over the age of 15 who live in the Orange Farm township. HIV prevalence in this area is 15.2% and about 25% of adult men in the community are already circumcised. Bophele Pele The project started in January 2008. Before starting, researchers spoke to
Male medical circumcision proceedure room.
the community about the idea of adult male circumcision, helped in setting up a community advisory board, organised community workshops to discuss the project and carried out surveys to find out just how much people knew about adult male circumcision and, very importantly, how willing men would be to undergo the operation. They found that the community were very much in support of the project and that men were very willing to be circumcised. Part of the project was to provide voluntary counselling and testing for HIV during the process of recruiting participants in the study. Once men were recruited, they were circumcised three days later. By November 2009, 14 011 men had been circumcised – which was more than one-third of those eligible for circumcision – and the level of uptake was rising steadily. So, on the face of it, this is a successful and rapid roll out of highquality, free adult male circumcision as an intevention against HIV. But, just how successful will the intervention be? Several challenges were encountered during the roll out. For example, only a quarter of the
Image: Anova Health
participants agreed to be tested for HIV. However, the way testing has been introduced has changed from voluntary counselling and testing (VCT) to provider-initiated counselling and testing, and since then the testing rates have gone up to more than 70%. These findings and those from similar programmes in Kenya and Uganda suggest that adult male circumcision programmes should be feasible, at least in the short term, as an HIV prevention strategy in low-income communities with a high prevalence of HIV and a low rate of circumcision. A second male medical circumcision (MMC) site that opened in November 2010 at Zola clinic in Soweto has been performing over 20 MMCs a day. In conclusion It is likely that male circumcision does not prevent transmission of HIV to women or to receptive male partners in men who have sex with men (MSM). But, it would seem to be a remarkably successful way of preventing HIV transmission and we have conclusive evidence that this procedure provides approximately 60% protection against the heterosexual acquisition of HIV in men. ■
A pill a day keeps HIV away – for men at least In a finding with the potential to fundamentally change strategies to slow the global HIV epidemic, a new study called iPrEx shows that individuals at high risk for HIV infection who took a single daily tablet containing two widely used HIV medications, emtricitabine and tenofovir (FTC/TDF), experienced an average of 43.8% fewer HIV infections than those who received a placebo pill. The study, reported in the New England Journal of Medicine, is the first evidence that this new HIV prevention method, called preexposure prophylaxis or PrEP, reduces HIV infection risk in people. The Desmond Tutu HIV Foundation, based at the University of Cape Town Health Science Faculty, and affiliated to
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the University of Cape Town was selected as one of 11 international sites to participate in this groundbreaking HIV prevention trial. A total of 2 499 HIV-negative men or transgender women who have sex with men, who are at high risk of HIV infection participated in the six-country iPrEx study. All received a comprehensive package of prevention services designed to reduce their risk of HIV infection throughout the trial. Half of study participants also received the PrEP pill, while the other half received a placebo. In all, 64 HIV infections were recorded among the 1 248 study participants who received a placebo pill, while 36 HIV infections were recorded among the 1 251 participants who received the study drug. The average reduction in HIV infection risk of 43.8% includes all study participants – even those who did not take the daily pill consistently.
Clients at the Simon Nkoli Centre for Men’s Health in Soweto.
Men: the neglected target Men who have sex with men are known to be at high risk of HIV infection and transmission but are often neglected in prevention and treatment campaigns. QUEST looks at how Health4Men is approaching HIV in this group.
Health4Men provides health services for men, specifically MSM, as well as research and community outreach programmes to try to evaluate and disseminate safer sex materials to this group. The organisation was started in 2008 when the South African Department of Health decided to focus on providing targeted HIVrelated services for groups who are most at risk for HIV transmission, including MSM, in accordance with the National Strategic Plan (NSP). Health4Men, a project of Anova Health Institute, is based in Cape Town and is developing focused, sexual health-related and prevention services for MSM through two clinics, the Ivan Toms Centre for Men’s Health in Cape Town and the Simon Nkoli Centre for Men’s Health in Soweto. Health4Men doesn’t confine its services to MSM, but also focuses on the sexual health needs of other high-risk male populations, including displaced persons and refugees, commercial sex workers and intravenous drug users. Current treatment for HIV is remarkably effective in preventing progression to AIDS, but cannot be the single solution to ending the pandemic. Prevention is absolutely key. So far, the most promising prevention methods have been biomedical – earlier introduction of antiretroviral therapy, new microbicide clinical trials and post-exposure prophylaxis. But one of the most important aspects is behavioural change as a way of preventing the spread of HIV. ▲ ▲
or some time now we have been bombarded with HIV prevention messages, all telling us that we need to have safer sex to avoid becoming infected. These messages are everywhere – on billboards, on the radio and on our TV screens. But in spite of this long-standing campaign, new infections continue and the rate of new infections in South Africa remains high. The cause is probably HIV fatigue – we have been hearing the same messages for so long that no one takes any notice anymore, and, if you are in one of the identified ‘most at risk populations’ for HIV acquisition, men who have sex with men (MSM), the messages are, in any case, not aimed at you. At risk In South Africa, what research there has been shows that African men who have sex with men are a particularly vulnerable group, specifically those who live in peri-urban informal settlements. Prevalence of HIV among MSM in South Africa would appear to be between 10.4% and 33.9%, according to different studies. As a result, MSM have been identified by both the South African government and major donors for targeted health interventions intended to decrease the impact of the virus on this group. A study in Soweto in 2009 found that overall HIV prevalence among MSM was 13.2%, with 33.9% among men who identified themselves as ‘gay’, 6.4% among bisexual men and 10.1% among men who identified themselves as ‘straight’ but who had sex with men.
The Ivan Toms Centre for Men’s Health in Cape Town. Image: Health4Men
The waiting room.
Quest 6(4) 2010 13
Counsellors explain HIV prevention at the Simon Nkoli Centre for Men’s Health in Soweto. Image: Health4Men Sexual orientation refers to an individual’s primary sexual attraction. With time, every person develops a sense of whether they are primarily sexually attracted to others of the same or the opposite sex. This may shift over time and in some individuals remain fluid. Bisexual individuals may be attracted to people of either sex, while homosexual people will primarily be attracted to people of the same sex and heterosexual people will be attracted to people of the opposite sex.
Gender identity tends to refer to the social norms that make up ‘femininity’ and ‘masculinity’ such as dress, mannerisms and the social roles generally assigned along gendered lines. Gender is not biologically determined, unlike one’s sex (male, female or intersex) but is socially created and may present in a multitude of ways. Gender identity may shift over time, and for some people may be fluid.
Homoprejudice can be defined as a set of individual or societal practices and attitudes that perpetuate bias against homosexual people, and/or behaviours. By defining these attitudes and behaviours as a prejudice rather than a phobia (fear), space is created in the human rights frame to hold people accountable for such beliefs and any actions resulting from them.
Who are men who have sex with men? Before you can target a population you need to understand them. The term MSM – men who have sex with men – refers to a diverse group of people that vary greatly in sexual identity, gender identity and sexual interactions. The common assumption is that MSM are ‘gay’ or homosexual, but MSM are very diverse and may not fit these common stereotypes. In fact some MSM identify themselves as heterosexual but may still have sex with other men. Importantly, many African MSM who would identify themselves as having a homosexual orientation do not identify with the mainly Eurocentric imagery, language and stereotypes that are associated with a ‘gay’ identity. Such men may even identify
14 Quest 6(4) 2010
as heterosexual, in spite of occasional sexual interactions with other men. Gender identity is the second important factor in understanding MSM. Sexual orientation and gender identity are often confused – a ‘gay’ man must identify as female and ‘straight’ men must identify as masculine. In reality many heterosexual men have very feminine aspects to their personality and many homosexual men may be very masculine. This brings us to sexual interactions – also not a simple matter of ‘gay’ and ‘straight’. Gay men may have sexual interactions with women and straight men may have sex with men. In a 2009 study of MSM in Malawi, Namibia and Botswana, over 50% had had sexual intercourse with both men and women in the last 6 months, and 17% were in concurrent relationships with men. It is only by starting to understand these complexities and realities that we will start to engage with MSM and not alienate the majority of MSM who do not fall into easy stereotypes. Why the focus on MSM? In most of the West, the MSM population is the group, rightly or wrongly, most associated wth HIV. However, in South Africa the perception is different – HIV is seen as a heterosexual disease – and indeed, the vast majority of HIV infection in South Africa is among the heterosexual population. As a result the MSM have become almost invisible in prevention campaigns – not least because of major social stigma (itself a feature of HIV infection) and homoprejudice. The lack of current information about HIV and other sexually transmitted infection (STIs) prevalence rates in the MSM sector in South Africa is, in part, the result of the way that epidemiological studies have been conducted. For example, UNAIDS’ annual HIV and AIDS epidemiological report on South Africa does not list information on
homosexual transmission, unlike many other countries. This is explained as being because no information has been collected on HIV rates in MSM from the numerous surveys it employs to put the fact sheet together. In South Africa we tend to rely on the anonymous antenatal surveys to determine HIV prevalence. This is a useful and cost-effective tool for monitoring HIV prevalence in heterosexual groups, but it leaves out other groups at risk or who play a role in HIV transmission patterns. Studies in other developing countries have shown that ignoring HIV among MSM has negative effects on the overall country-specific heterosexual epidemics and that improving prevention and treatment among MSM may lower HIV rates across the wider community. Crucially, we need to see same-sex sexual practices as part of normal sexual behaviour in a population and get away from the stereotypes – particularly the idea that anal sex is the only form of sexual interaction between MSM, or that anal sex only occurs between MSM. In fact, in a study in KwaZulu-Natal, between 10% and 14% of heterosexual male respondents reported having practised anal sex in the previous three months. We lack HIV preventive messaging aimed specifically at MSM in South Africa, and this, combined with a resistance to generic responsible sex messaging aimed at the heterosexual popuation has left the MSM population particularly vulnerable. Learning from the Health4Men experience Health4Men have five critical components: community engagement, research and training, information distribution, resource distribution and direct health services. Community engagement: the Ambassador programme
In order to ensure access to diverse hard-to-reach groupings of MSM
Western Cape ambassadors. Engaging with volunteers.
Health4Men has recruited a group of 20 volunteers, referred to as Ambassadors. Living in diverse geographical areas surrounding Cape Town, Ambassadors serve as a vital link between the organisation and marginalised men. Ambassadors distribute condoms and free sachets of water-based lubricant, as well as responsible sex media such as fact sheets, within their social nodes and keep Health4Men informed of dynamics related to the needs of MSM living in various communities. The Ambassador programme has been running for two years and includes regular meetings, and training and entrepreneurial opportunities. Ambassadors also participate in focus groups aimed at guiding Health4Men’s prevention campaigns. Research and training
publications. Information leaflets cover a large range of STIs that are prevalent amongst MSM populations, instructions on how to use condoms and femidoms, and how to access biomedical prevention such as post exposure prophylaxis (PEP). These leaflets are widely distributed through health service points and other distributors, in the hope that the information reaches a broader audience and can educate on issues beyond just HIV prevention.
needs to accompany lubricant distribution activities as many health service providers are not familiar with the product. Direct sexual health services
One of the most important prevention interventions that can be made for MSM is the wide distribution of condoms (male and female) and free water-based lubricant across the spectrum of public facilities and venues. Health4Men freely distributes condoms and sachets of lube to ‘gay’ venues across central Cape Town, key venues throughout the surrounding townships, and via its network of Ambassadors. An education campaign
A final component of the Health4Men model is the direct provision of sexual health and counselling services to MSM. Through the organisation’s research it has become clear that MSM feel uncomfortable using the public health system because of the high degree of homoprejudice they encounter at these sites. This homoprejudice, alongside a general ignorance of specifically MSM-related risks and sexual health concerns, can lead to MSM not seeking out health services, or receiving inadequate care when they do. In order to counter this, Health4Men runs two clinics – the Ivan Toms Centre for Men’s Health in Woodstock, Cape Town and the Simon Nkoli Centre for Men’s Health in Soweto – which provide sexual health services for men, and ▲ ▲
A core aspect of the work of Health4Men is to firstly explore the realities of MSM in South Africa, to try and move debates, prevention strategies and advocacy beyond the typical methods often based on stereotypes around homosexuality and ‘gay culture’. This research fills a critical gap through which we aim to increase the epidemiological, and social, understanding of risk and HIV transmission amongst MSM. Following on from this research, Health4Men has crafted a series of training programmes and workshops for health service providers (mainly primary health care doctors, nurses and community health workers on the frontlines of dealing with HIV) in dealing with MSM, as well as peereducation workshops so that MSM can help to disseminate information within their communities.
Health4Men specialises in creating informational brochures, fact sheets, posters and messaging that targets MSM and gay-identified men and are distributed through health clinics, public settings and mainstream ‘gay’
An innovative message from Health4Men.
Quest 6(4) 2010 15
A health check.
Sharing the message.
specifically for men who have sex with men. The organisation’s current emphasis on training and mentoring other community clinics to address South Africa’s MSM population aims at increased access to healthcare for such men in other areas. What have we learnt so far? While providing free sexual healthcare to MSM, including access to free antiretroviral treatment in partnership with the Department of Health, Health4Men places a premium on preventative campaigns. This has culminated in the organisation developing considerable expertise in designing such campaigns specifically for MSM within a context of stigma and homoprejudice. Health4Men emphasises that such messaging should never be perceived as being moralising or judgemental of
men’s sexual identities or behaviours, provided that all such behaviour is between consenting adults; even perceived moralising is interpreted as stigmatising, and much traditional safer sex messaging is thus rejected by MSM. The organisation’s messaging is designed to be inclusive of men who are HIV negative, HIV positive and the majority of men who don’t actually know their true HIV status. Likewise, messaging is inclusive of MSM who identify as being gay, bisexual and heterosexual in order not to alienate anyone. The emphasis is often placed on STIs other than HIV, such as syphilis, chlamydia or gornorrhoea, since many men find such messaging less intimidating than HIV. STIs also affect all men, irrespective of their HIV status or sexual identity. Symbols and even
terminology are carefully considered; an example is the avoidance of the term ‘HIV test’, since many people unconsciously associate the term ‘test’ with anxiety about passing or failing something. In contrast, the preferred term used by Health4Men is ‘HIV screening’. Likewise, the term ‘safer sex’ has been replaced with the concept of ‘responsible sex’. Any preventative messaging has to literally compete with the endless barrage of other social messaging men are exposed to on a daily basis, including the media and advertising, and needs to be innovative in order to attract attention. After all, the advertising industry often successfully uses sex to sell such diverse products as bathroom fittings, floor tiles and cars. Why can’t Health4Men use sex to sell responsible sex to MSM? ■
Whatever your game
be a winner - get screened for HiV
consistent use of condoms with water based lube when having anal sex, and reducing your number of sexual partners, are your best defence against HiV and stis. 16 Quest 6(4) 2010
TB Alliance launches first clinical trial of a novel TB drug regimen Tuberculosis kills nearly two million people annually and the disease is still being treated using old drugs with serious side-effects. QUEST looks at a new drug trial.
he Global Alliance for TB Drug Development (TB Alliance) recently announced the launch of the first clinical trial to test a novel TB regimen in a new development paradigm designed to speed new treatments to patients. This novel three-drug combination shows promise to treat both drug-sensitive (DSTB) and multidrug-resistant TB (MDR-TB), and alter the course of the TB pandemic by shortening and simplifying treatment worldwide. The TB pandemic TB kills nearly two million people each year – one person every 20 seconds. It is the third leading cause of death of women of child-bearing age in the developing world and the leading killer of people with HIV/AIDS. Due to the length and complexity of the current TB treatment, many patients are unable to complete their treatment, leading to increasing drug resistance, an emerging global health threat. More than half a million cases of drug-resistant TB emerge yearly. Unless these trends are reversed, drug resistance raises the spectre of future, untreatable TB epidemics. The new trials This Phase II trial, called NC001 or New Combination 1, tests the new TB drug candidates PA-824 and moxifloxacin in combination with pyrazinamide, an existing antibiotic commonly used in TB treatment today. Based on pre-clinical data, the combination has the potential to shorten treatment time for virtually all TB patients and harmonise the treatment of DS-TB and MDR-TB treatment with a single three-drug regimen. This is a particularly significant advance for MDR-TB patients, who today must take multiple types of drugs, including injectables, every day for up to two years. If successful, the experimental regimen will offer a shorter, simpler, safer, and more affordable treatment option for MDR-TB. Both new compounds are being developed by the non-profit organisation TB Alliance, one (moxifloxacin) in partnership with Bayer HealthCare AG. ‘We need more than a new drug to eradicate TB – we need entirely new regimens of TB drugs,’ said Mel Spigelman,
MD, President and Chief Executive Officer, TB Alliance. ‘The potential to offer a single regimen to treat both drug-sensitive and multidrug-resistant TB represents a monumental advance in the treatment of patients worldwide, and a tremendous step toward simplifying the delivery of TB treatment globally.’ Treating active TB requires a combination of drugs to prevent the development of drug resistance. Traditionally, researchers tested one new drug at a time in a series of lengthy and expensive clinical trials, meaning it would take decades to develop a completely novel drug combination. This new approach to drug development enables combinations of previously unregistered TB drugs to be tested together, with the goal of introducing truly innovative regimens in only a fraction of that time. This research approach is being championed by the Critical Path to TB Drug Regimens (www.CPTRInitiative. com), an initiative established to tackle the regulatory and other challenges associated with TB drug development. CPTR was founded in March 2010 by the Bill and Melinda Gates Foundation, the Critical Path Institute, and the TB Alliance. Nearly a dozen pharmaceutical companies, civil society organisations, the European and Developing Countries Clinical Trials Partnership (EDCTP), and others have signed on to the initiative’s guiding principles. The US Food and Drug Administration, other regulatory bodies, and the World Health Organisation have all shown support for this initiative. The trial involves 68 participants at two centres in South Africa, each receiving two weeks of treatment and three months of follow-up to evaluate effectiveness, safety, and tolerability. NC001 is an early bactericidal activity trial and is supported financially by United States Agency for International Development, the Bill and Melinda Gates Foundation, and the United Kingdom’s Department for International Development. There have been no new TB drugs for nearly 50 years and, until the past decade, no pipeline of TB drug candidates. Now,
A TB patient at Woodstock Hospital in Cape Town, swallows pills from the standard four-drug TB regimen, which he must take every day, under the supervision of medical staff. Image: Eric Miller
with increased investments in TB research and development, there are nine promising TB compounds in the pipeline from six antibiotic classes, making combination testing of new TB drugs possible. ‘New and powerful drugs to combat TB and MDR-TB are essential to achieving TB control goals outlined in the Global Plan to Stop TB 2011-2015 and ultimately to eliminate TB,’ said Mario Raviglione, Director of the World Health Organisation’s Stop TB Department. ‘It is extremely encouraging to see a growing pipeline of TB drug candidates that may revolutionise TB care and committed sponsors moving with speed and efficiency towards new regimens.’ NC001 also tests additional two-drug combinations (TMC207/pyrazinamide and PA-824/pyrazinamide) that may prove to be the building blocks of future regimens. Regimen development may become the new gold standard in TB research and offer lessons for other diseases requiring combination treatment, such as cancer, hepatitis C, and malaria. However, there remains a vital need for funding to bring new TB regimens through late-stage clinical trials. ‘We desperately need more funding and creative approaches to impact the global pandemic,’ reported Joanne Carter, Executive Director, RESULTS Educational Fund. ‘Support for research and development of new TB regimens is critical to reducing the impact of this disease and helping to eliminate one of the major health causes of entrenched poverty.’ ■
Quest 6(4) 2010 17
A cave looking over the Indian Ocean was the chosen home of early modern humans in South Africa. QUEST spoke to Curtis Marean to get the story.
Shellfish and colour early modern humans at the coast The view from Pinnacle Point.
An artist’s reconstruction of the flora and fauna of the Siberian tundra during the Pleistocene. Image: Wikimedia commons
The south coast of South Africa showing the location of the major archaeological sites. The now submerged Agulhas bank is also shown.
18 Quest 6(4) 2010
he ice ages began about 1.8 million years ago, during the Pleistocene epoch. This was a period that was marked by major changes in the Earth’s geology and climate. It was the time of many giant mammals such as the giant ground sloths, mammoths and mastodons and the sabre-toothed cat; it was also the time of their extinction. But for early humans, or hominins, it was a time of transition to a fully modern human, when the species became cognitively complex and, as a result, more efficient hunters – which may have at least partly been the cause of the extinction of these mammals. It was also a time of ice in the northern latitudes – large, longlasting masses of ice, glaciers, were extensive. But this was not a time of continuous glaciation. It was marked by glacial and interglacial periods, but during the last 400 000 years glacial climate was dominant. During glacials, the glacial ice expanded, but during the interglacials the climates were as warm as or warmer than those today. What did this mean for Africa? During this period the modern continents were more or less where they are now. At the maximum extent, ice covered around 30% of the Earth’s surface – most of it in the northern hemisphere. Each glacial period tied up huge volumes of water in continental ice sheets – 1 500 – 3 000 m thick – causing drops in sea level of 100 m or more across the globe. During interglacials – which is where we are today – sea levels rose and some coastlines were drowned.
The cliffs near PP13B showing the staircase and the team hauling equipment up. Image: SACP4
In the southern hemisphere, Antarctica was ice-bound through the entire Pleistocene, as it had been during the preceding Pliocene. The Andes were covered by the Patagonian ice cap in the south. There were glaciers in New Zealand and Tasmania. The modern decaying glaciers of Mount Kenya, Kilimanjaro and the Ruwenzori Range in east and central Africa were larger. Glaciers were present in the mountains of Ethiopia and to the west in the Atlas mountains. The climate of Africa changed drastically and most of Africa was drier during glacial climate. The Sahara was twice the size it is today, and most of southern Africa was drier. These harsh, desert-like conditions almost certainly meant that the ranges of Homo became restricted, with isolated populations probably confined to more habitable areas, and coasts would have been particularly attractive. Early modern humans This probable isolation of early modern human populations has major implications for evolution and it was this that led the interest of Curtis Marean, an archaeologist from Arizona State University. He has been studying early modern humans in South Africa since 1991, first on the west coast at Die Kelders and now near Mossel Bay on the south coast. He has recently theorised that during maximum glacial conditions there were only a handful of places in Africa that would have provided the conditions necessary to support human populations. A particularly long cold glacial stage
occurred between about 195 000 and 130 000 years ago when studies of genetics and fossils show that the modern human lineage appeared. Surprisingly, the genetic studies show that all modern humans have very low genetic diversity, and some estimates suggest that everyone alive on the planet today is descended from a small population that lived in Africa. Marean thought that one potential refuge for this progenitor population would have been the southern coast of South Africa, where the rich coastal resources are found along with highly diverse geophyte plants (plants with bulbs and corms) in the Cape Floral Region. So he looked for a cave that would have been close enough to the sea during the glacial maximum to have enough food and warmth, but that was high enough for its contents to have remained intact during the 5 m rise in sea levels that characterised the interglacial period about 123 000 years ago. Peter Nilsson (then a postgraduate student at University of Cape Town) had found some caves at Pinnacle Point (near Mossel Bay), overlooking the Indian Ocean, and together they began a research project there in 1999. One cave in particular caught Marean’s attention – named PP13B. It was about 15 m above sea level in the 60 m sheer cliff face. Difficult to climb to, a local ostrich farmer, Ricky van Rensburg, built a wooden staircase down the cliff to the cave, and in 2000 they began excavations with a team from South Africa and the USA, co-funded by the
At work inside PP13B.
National Research Foundation (RSA) and the National Science Foundation (USA). Marine resources and symbolic behaviour We know from genetic and fossil evidence that Homo sapiens (modern humans) arose in Africa between 200 000 and 100 000 years ago. At the time that Marean started his research, archaeologists hotly debated whether modern human behaviour first appeared 40 000 years ago in Europe, or much earlier in Africa. Evidence for symbolic behaviour is widely acknowledged by scientists to be a key indicator of modern human cognition. The technological phase of the origin of modern humans is the Middle Stone Age (MSA), which appeared as early as 280 000 years ago. South Africa has the richest record for the MSA, but much of it dates to after 120 000 years ago. This is probably because most of these sites are below the level at which the sea would have washed out earlier deposits by high sea levels about 123 000 years ago. In 2001 the team led by Christopher Henshilwood working at Blombos Cave showed that many indicators of modern human behaviour dated back ▲ ▲
The Pinnacle Point cave complex from the East.
Symbolic behaviour is characteristic of modern human cultures. It involves the ability to store information external to the person in language, ornaments, pictures and other symbols that represent something else. For example, people store and communicate information on their group or religious affiliation in the ornaments they wear.
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These ‘beauty shells’ were not harvested for food because they were dead when collected as indicated by beach wear. They include helmet shells (the snails) and dog cockels (the bivalves). The shells were studied by Antonieta Jerardino. Image: SACP4
to about 70 000 years ago – 30 000 years earlier than in Europe. This revolutionary result put all scientists’ eyes on South Africa. The new results from PP13B push that back a whopping 90 000 years to about 160 000 years ago!
LC-MSA north section – this photograph is digitally rectified to true grid space. It shows the major layers as well as where the dating samples were extracted for optically stimulated luminescence dating.
Mussel and limpet beds uncovered at low tide.
As sea levels rose and fell with glacial retreats and advances, the coastline off the south coast shifted. This figure shows the distance to the coastline over time from a 3D model of sea level change. For example, at about 140 Ka, the coast was over 90 km distant. The coastline model was developed by Erich Fisher.
This red piece of ochre has clear striations indicative of grinding. The ochre analysis was conducted by Ian Watts. Image: SACP4
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The importance of diet Why the relationship between coastal living and symbolic behaviour? When Marean and his colleagues excavated cave PP13B they found evidence that the early inhabitants collected molluscs (mussels and sea snails) and scavenged whales and seals along the shore. This evidence dated to 164 000 years ago, more than 40 000 years older than any previous evidence for coastal living. For millions of years hominin diet was restricted to terrestrial plants and animals. The expansion to shellfish is one of the last additions of a new class of foods to the human diet before animals started to be domesticated towards the end of the Pleistocene. People would not have settled along coastlines unless they had started to include shellfish and/or fish in their diet. Some researchers think that the addition of sea food was crucial to the coastal movement of populations out of Africa via the Red Sea coast and the early migration to Australia/New Guinea via coastal routes. However, Marean’s excavations show that early modern humans lived along the coast in South Africa long before the postulated dates for these migrations – which were after 60 000 years ago. So why shellfish and what is its importance? Marean and his colleagues think that shellfish and fish provided a critical source of food during the glacial maxima, when the surrounding land was extremely dry and unproductive. Much of South Africa may have been uninhabitable, with small populations concentrated on coastal platforms that are now submerged. Shellfish can be a reliable and predictable source of food. The collective gathering of shellfish, rather than other forms of more mobile
food, is associated with larger group sizes, more complex economic and social organisation, and with less mobile populations. And sea foods are nutritionally superb – they are particularly rich in omega-3 fatty acids, which are crucial to healthy brain growth. By 110 000 years ago we have strong evidence that people have in place a true ‘coastal adaptation’ in that their lives are based around the sea. For example, we find that they were collecting sea shells for their aesthetic value, and we know these are sea shells because they have beach wear (so were dead when collected) and are deep living species still collected today for their beauty. This coastal living in itself is likely to stimulate symbolic expression. Along with the early evidence for marine exploitation, PP13B also has worked ochre that was ground to produce powders, probably for body painting and possibly for colouring other organic materials such as wood and stone. The preference for reddish pigments was evident by 164 000 years ago, which is about 40 000 years earlier than found in other sites. The importance of this research is that Marean and colleagues were able to identify a site in which sediments with artefacts survived the rise in sea levels that occurred when the ice receded – showing that the previous dates at which both seafood in the diet and certain aspects of symbolic behaviour were influenced by the availability of sites, rather than giving a true reflection of the appearance of early modern human behaviour. It is likely that many more sites from this crucial glacial phase lay underwater off the south coast. Only the intrepid diver, ready to face the great white shark and treacherous waters, is likely to encounter those scientifically precious remains. ■ Curtis Marean is an archaeologist at the Arizona State University in Tempe who studies early modern humans in South Africa. He is the Associate Director of the Institute of Human Origins at ASU, and specialises in human adaptation, evolution and diversity and societies and their natural environments. He also has a keen interest in conservation and biodiversity.
Soweto from the air.
What is a megacity? The South African Agency for Science and Technology Advancement (SAASTA) gives some clues. Defining a megacity The definition of a megacity has been a bone of contention for most urban planners, policy-makers and academics. In most instances, the difference in opinion lies in the criteria people use in defining a particular city as ‘mega’. There is general consensus however in the United Nations, the World Bank as well as among some academics that a megacity is a city with an average projected population of at least 10 million people.
The Statue of Liberty in New York.
In 1950 there was only one megacity with 10 million or more inhabitants (New York, with a population of 12.5 million).
Image: Wikimedia commons
London was considered a megalopolis and it had a population of 8.7 million. By 2005, the number of megacities had increased to 20 ▲ ▲
For some critics, a megacity is defined by a population of 8 million people. There are however some ‘outliers’ such as Dorgan Karsada (1988) who use a 4 million mark to define a megacity. Such a low benchmarking might prove to be outdated in this era, as most cities in the top 30 list have at least 8 – 10 million inhabitants.
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Building a skyscraper.
and it is projected that there will be 22 megacities in 2015. Developing countries will have 17 of these 22 megacities in 2015. With 35 million residents in 2005, the metropolitan area of Tokyo was by far the most populous urban agglomeration in the world. Tokyo was followed by Ciudad de México (Mexico City) and New York-Newark, each with 19 million residents, and São Paulo, with 18 million people. In 2005, megacities accounted for about 9.3 per cent of the world’s urban population. In 2015, megacities Is there any difference between a megacity, global city and a world city? When defining a megacity, the number of inhabitants is said to be the sole defining factor, whereas global cities are not necessarily the biggest cities in the world, but are seen as metropolises whose political, cultural and commercial influence extends across the entire globe (e.g. New York City, Tokyo or London). The term megacity is frequently used as a synonym for super city, giant city, conurbation, megalopolis, world city and so forth. Unfortunately there is little consensus on what any of the abovementioned terms mean. Much of the global population growth is expected to occur in mega cities due to swift population growth and rapid urbanisation. Also, since developed nations tend to be highly urbanised already, most of the increased seems to be occurring in developing countries.
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Images of Tokyo.
Image: Wikimedia commons
are expected to account for 9.4 per cent of the world’s urban population. According to the UN Habitat and other institutions concerned with urbanisation trends and global urban processes, at least half of the world’s population is expected to live in urban areas by 2015. Urbanisation – the movement of people from the rural and peri-urban areas to the major cities – is the main cause of city expansion. In the past decade, however, there has been a trend that in some cities the natural growth either outweighs or is equal to the in-migration. Whereas the growth rate of cities in the developed world has decreased, it is projected that much of the urbanisation will take place in the developing world over the next decade or so. According to the United Nations, the rise of the megacity in developing countries over the past twenty years is of concern because housing and basic services can not be provided at the required pace. There is currently an extremely rapid displacement of developed country cities on the list of the world’s 30 largest cities by those in developing countries. Between 1980 and 2000 Lagos in Nigeria, Dhaka in Bangladesh, Cairo in Egypt, Tianjin in China, Hyderabad and Lahore in India,
along with several others in developing countries, were added to the list. By 2010 Lagos is projected to become the third largest city in the world. Megacities differ from smaller urban areas not only in population size but also in the scale of economy, infrastructure and associated environmental impacts. Megacities also act as magnets for people, functions, and organisations, structuring the country and the world around their social and economic dynamics. Megacities are the directional centres, the centres for technological innovation, the senders of symbolic messages, images and information, the providers of producer services, the collective factories of the new manufacturing, as well as depositories of the remnants of traditional manufacturing. Megacities are the nerve centres of our interconnected global system. Global distribution of megacities Of the world’s existing 20 megacities more than half are in Asia, four are in South America, three are in North America (including Mexico), two in Africa and one in Europe (Moscow). Still, the two global cities of Paris and London only fail to qualify by a wafer-thin margin. By
The railway station in Johannesburg.
■ Ideal base for production of goods ■ A market place for commodities and consumption ■ A place for cultural development and education ■ A nursery for civil spirit and social harmony Common problems in megacities While the growth of megacities often provides financial, social and cultural opportunities for its inhabitants, it can also bring economic crisis and a breakdown in the traditional social and cultural behaviour patterns that support less urbanised populations. Thus, megacities often have inadequate land for development, underdeveloped infrastructure, water shortages, poor sanitation, air pollution and traffic congestion. Megacities are also characterised by social, economic and environmental challenges and often too little space. In some instances, the social and economic inequalities result in the marginalisation of the poor. The result is that an economic underclass is created with little or no access to the amenities provided within the megacity. As Castells (1998) points out, megacities have proved to be sites of extreme poverty and neglect as well as places where wealth is
Figure 1. A schematic footprint of the Gauteng Global City Region Image: © Gauteng Provincial Government
contrasted by crime, violence and other forms of human abuse. Due to rapid urbanisation, land for housing becomes a scarce commodity in most megacities. Consequently, the mushrooming of slums and/or informal settlements is a common problem faced by megacities. In most instances, these slums that are hardly integrated into the urban infrastructure networks are the side-effect of the upswing in the real estate markets. For example, it is estimated that a total of one billion people live in slums around the world. ▲ ▲
far the largest collection of people is in Tokyo which, together with its conurbation (an extensive urban area formed when two or more cities, originally separate, coalesce to form a continuous metropolitan region), is home to a total of 35 million people. There are four other cities that each boasts around 20 million inhabitants (Mexico City, New York, São Paulo and Mumbai). The following megacities are located in coastal areas: Tokyo and Osaka (Japan), Shanghai and Tianjing (China), Bangkok (Thailand), Jakarta (Indonesia), Metro Manila (the Philippines), Bombay and Madras (India), Karachi (Pakistan), Istanbul (Turkey), New York and Los Angeles (USA), Buenos Aires (Argentina), Rio de Janeiro (Brazil), and Lagos (Nigeria). This is because coastal cities attract more inhabitants due to the beauty of their location – by the sea or river. Why are megacities so important? According to researchers, megacities are important because they are: ■ Engines of economic growth ■ Centers of technological and social dynamism ■ Centres of employment ■ Attractions of investment and trade
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Listed below are some of the challenges faced by megacities Social, economic and environmental challenges ■ Living space ■ Quality of life ■ Employment ■ Education ■ Crime ■ Nutrition ■ Slum growth ■ Inadequate housing ■ Poor transportation ■ Rising poverty levels ■ Increased crime rate ■ Environmental degradation ■ Pollution (high pollution industries, cars, etc.) ■ Waste disposal ■ Fresh water ■ Recreational spaces ■ Rapid coastal developments (conflicts) ■ Economic expansion ■ Depletion of fishery and disruption of marine ecosystem ■ Indiscriminate waste disposal. Points to ponder It can be limiting to only categorise a megacity based on the number of inhabitants in a given area. Some cities such as Johannesburg for instance, might have a population less than 10 million, but they are economically vibrant and subsequently significant. In 1986 Johannesburg was considered the only ‘world city’ on the African continent, but it was removed from the list due to sanctions against the apartheid regime. Hopefully it will re-gain its title soon. Academics and policy-makers have begun to acknowledge the importance of
the flows and linkages (in terms of people, goods, capital and services) between the city and its outskirts, normally referred to as the hinterland. This acknowledgement of connectivity between cities and their hinterland, coupled with the appreciation of city-to-city interactions, is called city-regionalism. An example of a city region would be the Gauteng Global City Region, which comprises Johannesburg, Tshwane and Ekurhuleni [Figure 1]. Cities must not be viewed in isolation. Their resilience (that is their capacity to sustain a population as well as everyday economic, social, political and ecological pressures and processes) is dependent on the interplay between social, economic, spatial and ecological activities or processes. In short, a city is a result of a range of complex processes. For development planners, therefore, a city is part of a complex system. For the system to function, it is critical for people to act in a responsible manner. Responsible actions such as conserving water, managing and/ recycling waste, avoiding soil erosion for example, result in sustainable development. The most populous megacity in Africa Lagos in Nigeria, with over 10 million people, an annual population growth of 9% and with a projected population of 22 million by 2025, is Africa’s largest megacity. Cairo was the first African megacity which had a population of 10.6 million in 2000 and has a projected population of 12.7 million in 2010. ■
References Barbière, J. and Li, H (eds). (2001) Third Millennium Special Issue on Megacities. Review of International Political Economy, 5, 1, 1 – 37. Beavon, K. S. O. (2004) Johannesburg – the making and shaping of the city. Prretoria, UNISA Press. Castells, M. (1998) Why the Megacities focus: Megacities in the New World disorders. The Mega-Cities Project Publication MCP-018. Fuchs, R. J. (1994) Introduction and Chapter 1. In Fuchs, R. J. Brennen, E. Chamie, J. Lo, F. and Uitto, J. I (eds) Mega-city growth and the Future. New York, United Nations University Press. Gaffney, J. S. Marley, N.S. Cunningham, M. M. and Doskey, P.V. (1999) Measurements of peroxyacyl nitrates (PANS) in Mexico City: Implications for megacity air quality impacts on regional scales. Atmospheric Environment, 33, 5003 – 5012. Gilbert, A. (1996) The Mega-city in Latin America. New York, United Nations University Press. Gurjar, B.R. and Lieliveld, J. (2005) New Directions: Megacities and Global Change. Atmospheric Environment, 39, 2, 391 – 393. Just, T. and Thater, C. (2008) Megacities, Boundless Growth? dbresearch.com www. dbresearch.com. Li, H. (2003) ‘Management of Coastal MegaCities—A New Challenge in The 21st Century’, Marine Policy 27 (2003) 333 – 337. Molina, M.J. and Molina, L.T. (2004) Critical Review: Megacities and Atmospheric Pollution. Journal of Air and Waste Management Association. 54, 6, 644 – 680. Nicholls, R. J. (1995) Coastal Megacities and Climate Change. GeoJournal 37, 3, 369 – 379. United Nations. World Urbanization Prospects, 1999. Ziv, J. and Cox, W. (2007) Megacities and Affluence: Transport and Land Use Considerations. Presentation to the World Conference on Transport Research. Berkeley. Zwingle, E. Cities: Challenges of Humanity. National Geographic Magazine. (November 2002).
CSIR – Our future through science The Council for Scientific and Industrial Research (CSIR) is a leading scientific and technology research, development and implementation organisation in Africa. It undertakes directed and multidisciplinary research and technological innovation to improve the quality of life of South Africans. To ensure that it achieves maximum impact, the CSIR focuses its research and development to impact in the following portfolio areas: Built Environment; Health; Industry; Natural Environment; Energy; Defence; and security. Contact: Tel: 012 841 2911 e-mail: firstname.lastname@example.org www.csir.co.za
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Solving SALT’s image quality problems Lisa Crause discusses how local scientists were able to realign Southern African Large Telescope’s secondary optics to clean up the images delivered by the telescope.
he SALT project began in the late 1990s as a southern hemisphere counterpart to the 10-m Hobby-Eberly Telescope (HET) built at McDonald Observatory in West Texas. This unconventional telescope design uses a spherical (rather than parabolic) primary mirror, composed of 91 hexagonal 1-m segments, to simplify the engineering and hence reduce cost. The penalty for this saving is that, because the primary mirror array is spherically figured, the reflected light does not automatically come to a common focus. Rays striking the outer parts of the array are not focused at the same distance as those that reflect off the central section of the primary array. This effect, known as spherical aberration, needs to be eliminated to allow the light to be brought to a useable focus. A complicated set of secondary optics (the spherical aberration corrector or SAC) located on the tracker payload, near the prime focus of the telescope, is responsible for this tidying up of the wavefront. The SAC then feeds the ‘cleaned up’ starlight into the telescope’s various instruments for scientific interrogation. In SALT’s case, these instruments include an imager (SALTICAM), a multi-purpose spectrograph (the Robert Stobie Spectrograph, or RSS) and a Fibre Instrument Feed (FIF) that will send light to a High Resolution Spectrograph (HRS) which is still being built. A spectrograph is an instrument that disperses light into a spectrum so that the intensity at each wavelength (colour) can be recorded on a detector and analysed.
phase began. During 2006, two serious problems were identified: (a) SALT’s image quality (IQ) was found to be severely degraded by a focus gradient and other aberrations across the field of view and (b) the efficiency of the RSS was greatly reduced compared to its design, specifically at the blue end of the instrument’s spectral range – where it was intended to be particularly sensitive. Unravelling these two puzzles required extensive diagnostic efforts, the engineering equivalents of intriguing murder-mystery investigations. In the case of the IQ issue, thorough cross-examination of all the suspects eventually showed that the instruments and the primary mirror were not to blame, indicating (by elimination) that the SAC was responsible. This was a daunting conclusion to reach as it meant that the telescope’s most serious problem resided within the one sub-system that to date had been treated as a sacred and terrifying black box... (The RSS saga is a story for another day, but suffice it to say that it looks to be on track for a happy ending!)
Safely removing the SAC from the payload was a slow, complex and fairly agonising process. See if you can spot six of the dedicated crew members in this photo! Image: Lisa Crause
Optical design software was used to simulate the effects of tilting and/or misaligning the various SAC mirrors and confirmed that a focus gradient could be induced in this way. However, the magnitude of the required displacement was huge
Diagnostics Initial construction of SALT was completed in 2005 and the telescope was inaugurated by President Mbeki in November 2005, after which the testing, commissioning and verification
SALT (left) has a payload (centre), situated on the tracker at the top of the telescope, which carries the instruments and the Spherical Aberration Corrector (SAC). The SAC consists of four precisely shaped mirrors (red in cross-section in the schematic on the right) that work together to remove the optical aberration introduced by the telescope’s primary mirror. Image: Lisa Crause
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The new steel (lower) and aluminium (upper) interface collars had to be fitted to the SAC before the four mirrors could be aligned and tested. Image: Lisa Crause
This equipment was used to test the surface figure of M2. M3 had been removed from the SAC at this point to allow the interferometer (the black instrument in the top left of the photograph) to illuminate the surface of M2. Image: Lisa Crause
in optical terms and implied that something had gone badly wrong with the SAC. Yet more detective work showed that the different rates of expansion and contraction between the steel framework of the SAC and the aluminium ring on the payload were causing substantial forces to be transmitted into the SAC, compromising the delicate alignment of the four SAC mirrors. To repair this, the steel-aluminium interface needed to be replaced and the corrector mirrors had to be realigned. These interventions could not be performed with the SAC on the telescope so the corrector was brought down from the tracker in April of 2009. With the precious hardware safely on the ground, the new interface
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This clean-room photo shows the SAC attached to its test rig and tilted over to the telescope’s operational angle of 37º. The distortion of the image is due to the photograph being taken with a super wide-angle (fisheye) lens. Image: Lisa Crause
collars, one made of steel which bolts to the steel SAC cage and another of aluminium which bolts to the aluminium ring on the payload, could be installed. Three bearing assemblies, set 120° apart, link the two collars and take up any stresses introduced by differences in expansion of the steel and aluminium. The SAC, with its new collars, securely mounted on a fully adjustable frame, was then ready for realignment and testing. A clean-room was set up in SALT’s mirror coating facility for this purpose and the IQ team, a small group of astronomers and engineers from the South African Astronomical Observatory (SAAO), had to acquire and fully acquaint themselves with various pieces of specialised equipment to carry out the repair.
Testing A basic description of the SAC realignment and testing procedure that was developed by Dr Darragh O’Donoghue (SAAO astronomer and IQ team leader) is given below, but readers curious about the gory details are directed to the photo-rich SALT IQ blog at http://saltiqmission.blogspot.com. The mirrors that make up the telescope are referred to as M1–M5, M1 being the primary array (the 91 segments that function as a single mirror) and M2–M5 making up the corrector. M2 was used to set up the SAC’s coordinate system and was never adjusted, so that it served as the reference throughout the realignment and testing process. The other three SAC mirrors were then aligned with respect to M2 – first M5 relative to M2, then M4 with
The combination of excellent atmospheric conditions and a good primary mirror alignment on the night of 28 August 2010 left no room for excuses: if the SAC had been fixed, we ought to get great images. And we did – sharp, uniform stars over the telescope’s full field of view!
At last – the dome crane gently lifted the SAC back up to its home on the tracker. Image: Lisa Crause
respect to M5 via a wavefront test of the pair and lastly, M3 was aligned with respect to the rest of the system using a CGH test. Along the way, the surface figures of M5, M4, M2 and the particularly complex M3 were also tested and shown to meet their respective specifications. Execution of the repair plan was strategically interrupted to allow the two upward-looking SAC mirrors (M5 and M3) to be removed from the SAC and cleaned. This was necessary because their optical surfaces had become very dusty and dirty while the corrector was up on the telescope. Although handling and cleaning precision mirrors is a nerve racking process, both these procedures were highly successful in restoring the reflectivity of the two mirrors. The 16 months of painstaking effort invested in the SAC repair made it almost impossible to watch the corrector dangling on the dome crane as it was hoisted back up to the tracker on 10 August 2010. To everyone’s great relief, the lift and re-integration went smoothly and we could proceed with
aligning the SAC to the payload, in preparation for the only truly definitive test: on-sky imaging. Success! Initial images showed that the most serious part of the IQ problem – the focus gradient – was indeed gone, but stable, perfectly round stars remained illusive. Soon the issue was traced to the auto-collimator, an instrument mounted on the payload to provide feedback for keeping the SAC orientated exactly perpendicular to the primary mirror. Modifications to the auto-collimator mount and its relocation to the SAC’s steel collar made all the difference and once weather conditions permitted, the magical images that the entire SALT community has anxiously waited for were finally obtained. Beautifully sharp 1.1 arc-second stars could be seen over the telescope’s full field of view! Close inspection actually revealed that yet another, although much smaller, problem still exists – due to the way the primary mirror segments are aligned with one another. It is indicative of how far we have come
This schematic shows the optical layout of the CGH system test. The rays in the diagram represent the path of the laser light as it travels from the interferometer (left) and reflects off each of the SAC mirrors in turn, until it reaches the CGH. Here the light gets redirected all the way back through the system until it reenters the interferometer. The outgoing and incoming beams then interfere to produce fringes which allow the performance of the entire optical system to be evaluated.
that we can even detect such a minor deviation from optimum IQ, but it’s even more exciting that we know how to go about correcting that as well. The SAC fix is the most radical intervention that SALT has undergone since its completion. The fact that it was carried out entirely within our own facilities, by members of our own staff, is a significant breakthrough, which takes SALT’s technical capacity to a new level. This places the telescope’s most complex sub-system under full control of the SALT team, an unthinkable prospect just a few years ago. As for the future of SALT itself, a recent speech by Professor Ted Williams (Chairman of the SALT Board of Directors) perfectly captured the expectant mood, likening the situation to that which astronomers experience after sunset – the excitement that builds when a clear sky begins to darken and one senses great observing ahead! ■ Dr Lisa Crause is an astronomer in the instrument division of SAAO and was the camera-toting member of the IQ team.
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The RV Ellen Khuzwayo.
Albrecht Götz, Sven Kerwath and Toufiek Samaai tell QUEST about the first deployment of the National Research Foundation’s Remotely Operated Vehicle (ROV).
Exploring the depths
Figure 1. The Falcon Seaeye Remotely Operated Vehicle (ROV) manufactured by SAAB (frontal view) showing sonar head, high-resolution camera, umbilical, buoyancy pack, LED light, thruster, laser-scaling camera and 3-function hydraulic manipulator arm. Image: SAEON
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Figure 2. Reefs explored on the Agulhas Bank.
he shelf areas of the world’s oceans constitute some of the most productive and ecologically important marine habitats. Unfortunately, more than 95% of the seafloor is situated in waters deeper than 40 m, which makes researching these areas by SCUBA diving impossible. In 2008, the African Coelacanth Environmental Programme (ACEP), hosted by the South African Institute for Aquatic Biodiversity (SAIAB) through a grant from the Department of Science and Technology (DST), purchased a Remotely Operated Vehicle (ROV) to explore depth zones beyond SCUBA range. Depending on their purpose ROVs come in all shapes and sizes (between 3 kg for limited inspections and 60 tons for subsea mining operations). The Falcon is a relatively small (90 kg) ROV of the type ‘observation vehicle with limited intervention capabilities’. It carries a suit of cameras, lights and a manipulator arm (Figure 1). To get familiar with the new equipment, it was decided to deploy the ROV during a voyage of the RV Ellen Khuzwayo to the Agulhas Bank, as part of an ongoing research project conducted by the Department of Agriculture, Forestry and Fisheries (DAFF), to assess linefish stocks and invertebrate communities associated with offshore reefs that cannot be sampled with trawl gear. These reefs consist of relatively
The ROV is taken out of its store.Image: SAEON
The ROV is launched from the aft deck of the vessel.
The ROV is transferred onto the aft deck of the vessel. Image: SAEON
ab c d
Figure 3. The laser-scaling camera of the ROV can be used to measure invertebrates (a) and fish (b) by pointing the parallel laser beams onto a target. It takes a lot of practice to sample invertebrate specimens with the manipulator arm (c). For ichthyofauna composition and size frequency estimates, fish can be attracted with a bait-container. Image: SAEON
relatively shallow Martha’s Reef and 12-Mile Bank. Essentially, the ROV is ‘flown’ from the control room, using the pilots and the sonar screen. Here, we established methods to measure invertebrates (Figure 3a) and fish (Figure 3b) with the laser-scaling camera, sample invertebrates with the manipulator arm (Figure 3c) and count fish along a transect line or around a bait-container (Figure 3d). After these ‘practice trials’ our first exploratory dives took us to the Alphard Banks, a cluster of slender pinnacles of volcanic origin. Much
shallow (20 – 70 meters) rocky banks and pinnacles between 20 and 150 km offshore (Figure 2). The Ellen Khuzwayo is a purposebuilt 43-meter research ship which can work up to 200 nautical miles offshore. She accommodates a crew of 21 and fulfilled the requirements for initial trial deployments of the ROV at sea. The ROV was taken out of store, transferred to the aft deck of the vessel and launched using the Aframe. We used the first deployments to assess the ability of the ROV to conduct quantitative surveys over the
Scientists ‘fly’ the ROV from the control room using the ‘pilots’ and the control screen. Image: SAEON
Figure 4. Seabed topography of the Alphard Banks. The steepest pinnacle rises sharply from about 90 to less than 20 meters under the sea surface (insert).
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like on a mountain, the steep sloping seabed exhibits a rapid depth-related habitat succession (Figure 4). The dome-shaped smooth pinnacle appeared at about 20 meters below the ocean harbouring loose stands of spined kelp (Figure 5a) with patches of hydrozoans and encrusting sponges. At about 30 meters the kelp started to disappear and the encrusting invertebrates were replaced by a more diverse upright-growing benthic community. This habitat change coincided with a sharp drop in temperature at about 35 meters (Figure 5c-d). Smooth-hound sharks were most abundant around the thermocline (Figure 5b). It seemed as if these sharks were ‘patrolling’ along an invisible line of rapid temperature change. This interesting phenomenon might be related to ‘dial vertical movements’ observed in other benthic, predatory fish such as dogfish sharks, where it also occurred in habitats with steep seabed topography and strong thermal stratification. In such environments,
metabolic energy savings can be made by exploiting prey and thermal gradients. Unfortunately, our cut-off depth for this first ROV trip was 40 m (within SCUBA recovery range) and we couldn’t explore the deeper slopes of the pinnacle. A follow-up trip to the Alphard Banks, this time without depth limit, took place during the next linefish directed cruise of the Ellen Khuzwayo, which took place in November 2010. ■ Dr Albrecht Götz received his PhD in 2006 from Rhodes University, Grahamstown and has since worked as a researcher at the Elwandle Node of the South Environmental Observation Network (SAEON). His research interests focus around the development of long-term monitoring protocols for fish and benthic invertebrates. Dr Sven Kerwath is a scientist at the Department for Agriculture, Forestry and Fisheries (DAFF). He is the project leader and a specialist on inshore fish resources. Dr Toufiek Samaai is a scientist at the Department for Environmental Affaires (DEA). He complements the team with a vast knowledge on benthic invertebrate ecology and taxonomy.
c Figure 5. The pinnacle explored on the Alphard Banks. Pinnacle top with spined kelp and smooth-hound sharks at 25 m (a), accumulation of sharks and absence of kelp at 35 meters (b) and temperature profile (c) in relation to seabed topography (d). Image: SAEON
The sonar screen.
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The spectre of ocean acidification Increasing acidification of the world’s oceans, as a result of the build-up of atmospheric carbon dioxide, is harming marine life such as corals. Mike Lucas explains.
limate change, due largely to man’s activities, is a serious environmental issue that will affect us all. It will also affect plants and animals in most of the ecosystems that we are familiar with. Some effects will make life difficult for many organisms, but others will thrive on change – a fact often overlooked in the climate change debate. In this article I will explain how increasing atmospheric CO2 concentrations are affecting the chemistry of the oceans in ways that may adversely affect many calcifying marine organisms that build calcium carbonate shells in a process called calcification.
Human activities and the oceanic ‘sink’ for carbon dioxide Overwhelming evidence implicates human activities as being responsible for current rapid climate change, over and above natural longterm climatic cycles. Humans are currently emitting about 9 Gt y-1 (= 9 billion tons per year) of carbon dioxide (CO2) into the atmosphere from burning fossil fuels and from land-use changes. Atmospheric concentrations (~388 ppmv) have now risen to unprecedented levels. Unless there is a reduction in emissions by 2100, ecosystems will face CO2 concentrations that were last seen more than 650 000 years ago, and global temperatures will become the highest experienced in the past 740 000 years. About 45% of current emissions accumulate in the atmosphere, while the world’s oceans take up about 25% of this, and land-masses remove the remaining 30%. Ocean processes that remove atmospheric CO2 consist of the ‘biological carbon pump’ (see QUEST 6(3), page 36) and the ‘physical solubility pump’.
The latter process, as the name implies, depends on the solubility of gases (e.g. CO2) in water, where the solubility of a gas increases with decreasing water temperature, while dissolved gases become less soluble as water is warmed up. Thus cold oceans take up more CO2 by this process than do warm oceans, and indeed, where oceans are warm enough, CO2 may be ‘out-gassed’ back into the atmosphere. Overall, cold polar oceans are therefore generally a ‘sink’ for CO2, while warm sub-tropical and tropical oceans are often a ‘source’ of CO2 back into the atmosphere. The Southern Ocean’s extreme coldness (of < 2 °C), combined with its size, as well as the contribution of the biological carbon pump, provide the reasons why this ocean alone currently removes about 50% of the total global ocean uptake of CO2 (about 2.2 Gt y-1). However, the increasing uptake of CO2 by the global oceans is causing profound changes in their chemical composition and pH, which may have adverse impacts on calcifying organisms. These include ‘hard’ corals, delicate planktonic pteropods and an important group of phytoplankton called coccolithophores. The chemistry of ocean acidification At the start, it is important to understand that seawater has a normal pH of about 8.1 (neutral is about 7), and that pH values in the range 1 – 6 mean that the water is acid, while values in the range 8 – 14 mean that the water is alkaline, or basic. The spectre of changing ocean pH, or ocean acidification as it is more evocatively known, occurs as
The edge of the ice pack in the cold Southern Ocean. Image: Mike Lucas
Biological and physical pumps for carbon dioxide. Images: Wikimedia commons
A diverse coral community.
Image: Charles Griffiths
Quest 6(4) 2010 31
A micrograph of a coccolithophore.
Image: Wikimedia commons
A pteropod, probably Limacina helicina.Image: Wikimedia commons
Figure 1. Increasing CO2 concentrations at three sites from 1985 – 2005 (left) causing corresponding falls in pH (right). IPPC, AR4, 2007.
Figure 2. The effect of changing pH on the ocean’s carbonate and bicarbonate chemistry.
Figure 3. The predicted and accelerating changes in ocean pH.
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increasing amounts of atmospheric CO2 become dissolved in the ocean, combining with water (H2O) to form a weak solution of carbonic acid (H2CO3). However, the buffering capacity of the oceans is substantial, due to the presence of carbonate (CO32-) and bicarbonate (HCO3-) ions, so the current change in ocean pH is almost undetectable. The reason for this lies in the unique chemistry of seawater. When carbonic acid is formed, it dissociates in seawater to form hydrogen ions (H+) and bicarbonate ions (HCO3-). It is the free H+ ions that lower pH, and if free H+ ions increase ten-fold, pH falls by 1 unit. This does not happen, however, because the H+ ions combine with carbonate (CO32-) in seawater to form more bicarbonate (HCO3-). These reactions are summarised in the following equations: i) CO2 + H2O → H2CO3 ii) H2CO3 → H+ + HCO3iii) H+ + CO32- → HCO3The net effect of these processes is that concentrations of CO32- fall, while H2CO3, H+ and HCO3- all increase as more CO2 is dissolved into the oceans, although the increase in H+ is minimised (buffered). This is why pH change in seawater is slow. By contrast, if you bubble CO2 into freshwater, which has low CO32- and HCO3- ion concentrations, the pH can become quite acidic (pH 4). In fact carbonated fizzy drinks such as Coke have a similar acidic pH, so if you placed a tooth into a glass of Coke overnight, it would become quite eroded! But because of the buffering effect of seawater, pH has only fallen from ~8.12 to ~8.08 from 1985-
2005, a change of just 0.04 pH units to present, as shown in Figure 1, while the effect of changing pH on the ocean’s carbonate/bicarbonate chemistry is illustrated in Figure 2. However these changes are accelerating much faster than previously thought (0.1 pH units since 1750, but of that, by 0.06 units since 1980), particularly in surface waters of cold polar oceans (Figure 3), and because of the unique chemistry of seawater, these changes will be very long-lasting and will likely affect calcifying organisms. The effect on calcification Calcification, or the process of building calcium carbonate shells, depends on combining calcium (Ca2+) ions with bicarbonate (HCO3-) ions to form calcium carbonate; as in the following equation: Ca2+ + 2HCO3- → CaCO3 + CO2 + H2O Note that calcification initially increases the concentration of CO2 in seawater, although ultimately CO2 is removed when the cells die and sink. But the problem with changing ocean pH is that calcification is a reversible process, meaning that CaCO3 dissolution can occur. There are two sides to this. First, as pH is lowered, CaCO3 starts to dissolve, thus eroding or weakening the shells of calcifying organisms. More importantly, the concentration of CO32- in seawater falls as more CO2 becomes dissolved into the ocean (equation ii, above), which reduces the saturation state of calcite (Ω-cal) in the ocean, the form of calcium carbonate created by coccolithophores. Where Ω-cal falls below 1, as in cold polar oceans (see
Figure 3), it becomes very difficult for coccolithophores to form their calcite ‘liths’, and calcite dissolution will tend to occur instead. Calcium carbonate in fact exists in two crystalline forms, namely calcite and aragonite. Calcite is the more robust form (e.g. coccolithophores and hard corals) and therefore less susceptible to dissolution than the more weakly structured aragonite (e.g. pteropods). Pteropods, which underpin the food web in the Arctic Ocean, appear to be particularly at risk because their shells are thin and delicate. But to test these fears, many laboratory experiments have been conducted on a wide variety of calcifying organisms to assess the effect of changing pH on calcification rates, or on the structural integrity of shells exposed to low pH, including shellfish (mussels, oysters), pteropods, corals and coccolithophores. Have coccolithophores been negatively affected? This question has occupied researchers for several years now, focussing their efforts in particular on Emiliana huxleyi. This species forms very distinct and extensive blooms in the North Atlantic that are quite visible from space. Coccolithophore blooms appear as milky whirls in surface waters, because the ‘liths’ that make up their skeletons reflect light easily, which is readily detected by satellites. But why study them? Coccolithophore calcification accounts for about a third of current marine CaCO3 formation. Coccolithophores are also considered to be an important but complex component of the biological carbon pump, because the heavy ‘liths’ act as ‘ballast’, which facilitates the downward flux of their cells (as particulate organic carbon) when they die. This process therefore removes CO2 from the atmosphere and exports it into the deep ocean where it is locked away for hundreds to thousands of years, which, it is hoped, will help slow down the rate of CO2 accumulation in the atmosphere. To test the effect of changing ocean pH on coccolithophores, scientists have subjected coccolithophores to a range of pH in laboratory cultures and then carefully measured the dimensions of coccolithophore ‘liths’, looking for evidence of calcite
dissolution and other structural changes. In some experiments, significant changes were observed, in which the ‘liths’ became pitted and deformed, suggesting that with increasing ocean acidification, coccolithophore calcification rates and their structural integrity might suffer. However, other similar experiments showed exactly the opposite trend, where calcification rates increased and the ‘liths’ became larger and stronger. How can such diverse results be reconciled? Part of the problem is the very nature of laboratory experiments, where exact environmental conditions are extremely difficult to reproduce. Recognising this, a student (Anastasia Charalampopoulou) at the National Oceanography Centre (NOC; UK) has undertaken a number of research cruises with me in both the Arctic and Southern Oceans to measure coccolithophore calcification rates and the structural morphology of natural populations of these organisms. Her results have shown that both laboratory studies are right in their own way. What emerges is that different species respond to ocean acidification in different ways – some species are sensitive to these changes and their populations are likely to suffer, while others appear to respond positively. Changing ocean pH therefore alters coccolithophore community structure Such findings provide yet another example of the way in which ecosystems and the animals and plants that inhabit them are adaptable to change. This may mean that some species die out, while others fill their niche. This is does not alter the fact that ocean acidification is a problem, but nature has a way of finding solutions, if given sufficient space and time. We may not like the outcome, and it may not suit us as humans, but change has been a part of the evolution of life on Earth over millions of years, and this pattern will remain. ■ Associate Professor Mike Lucas is employed within the University of Cape Town’s Zoology Department. He is also an Honorary Research Associate at the National Oceanography Centre (NOC) in Southampton, UK. He conducts much of his research in the North and South Atlantic, as well as in the Southern Ocean and in the Benguela upwelling system. He is a member of the southern African SOLAS Network, which forms part of the International SOLAS Project.
The coccolithophore, Emiliana huxleyi.
Image: Mike Lucas
Milky swirls of a coccolithophore bloom off Newfoundland, in the northwest Atlantic. Image: Caronnation.org
The South African antarctic research ship, SA Agulhas, pushes through the pack ice towards the distant ice shelf. Image: Mike Lucas
Quest 6(4) 2010 33
A savanna system dominated by grassland. Image: BJ Nxele
Bush encroachment in savanna systems: a cause for concern in land-use management It is not just alien invaders that cause concern in delicate savanna systems, but mainly changes in the density of indigenous species. Beka Nxele explains the ‘savanna problem’.
he savanna biome occupies the majority of the surface area of southern Africa. Savannas are utilised largely for their productivity and are roughly defined by climatic conditions, with rainfall ranging from anything up to around 1 000 mm per annum, making savannas arid (dry) or semi-arid. The biome is also categorised according to the density of trees, mainly acacia species (where acacia means ‘thorn’), relative to the amount of grassland. Savanna systems It is the coexistence of these two life forms – the trees and grasses or woody layer and the herbaceous layer – that distinctly defines a savanna system. When there is more grassland than trees, the system is called an open savanna system. If there are more trees than grassland, it is called a closed savanna system. The process by which a savanna becomes a closed system is called bush encroachment. It is the open grassland phase that attracts human use and also sustains higher densities of biota. So, in both human and biodiversity terms, the open savanna may be the preferred system. Bush encroachment
The species that encroach in savannas are normally not alien invasives but rather indigenous species that
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suddenly become invasive. Most of these species are members of the Mimosaceae family (Acacia species). Common encroaching species are Blackthorn (Acacia mellifera subsp. detinens), A. karoo, A. reficiens, A. tortilis and Sickle bush (Dichrostachys cinerea). These encroachers normally have thorns and contain compounds (for instance phenolics) that are unpleasant to herbivores, which prevents grazing. These species (especially Acacia mellifera) form impenetrable thickets, which reduce the ability of the land to sustain people, livestock and game. The factors and the interaction(s) between factors that drive savanna systems to shift from one phase to the other are still not yet well understood. This leads to the so-called ‘savanna problem’ – why is it that savanna systems fluctuate between closed and open, with neither trees nor grassland permanently dominating? Lack of understanding of the dynamics of such a system has interested scientists, farmers and land-use managers for decades. Open savanna and human use Open savanna is generally regarded as more useful land for human use and land-use managers try to maintain this state. Open savannas contain many different types of grass and
other herbaceous species. They also contain a vast array of animal species that depend on these grasses and predators, which, in turn, depend on these animals. This leads to greater biodiversity within the open savanna system, compared with the closed system. This biodiverse environment is used by farmers for grazing livestock and by conservation agencies – who maintain protected areas. However, both these uses lead to fencing, which causes problems when the savanna system undergoes a natural shift from an open to a closed phase. In a fenced environment it becomes difficult for game and livestock to move to better grazing and eventually the land has less commercial value. This leaves farmers and conservation managers with the option of either changing how the land is used or controlling the density of trees in some way, leaving grassland open for grazing. Such management techniques can either be natural (for example, manipulating fire regimes and/or the density of herbivores) or manual (bringing in clearing teams to cut trees). Natural techniques will often cost less money to implement but may take longer to be effective, while manual techniques are costly but will take less time to yield the
Q Conservation required state. Little is known about what triggers these shifts from one phase to another, but it is these shifts that make savanna systems uniquely sensitive; potentially a problem when they occupy so much of Africa’s area and are so useful to humans. The land use management problem is one of trying to maintain the most useful phase in the face of a natural tendency of the system to shift. Unlocking the ‘savanna problem’ There have been many attempts to find a generalised model to explain the phase shifts that will accommodate most savanna systems. The two-layer hypothesis
The classic explanation is the two-layer hypothesis of tree-grass coexistence that was proposed by Heinrich Walter, in 1939. To Walter the key factor was rainfall or precipitation. He narrowed this phenomenon down to root separation, assuming that water was the limiting factor and that grasses would use the topsoil moisture while woody plants used subsoil moisture. In this system any disturbance such as heavy grazing, intense fires, drought and so on would remove grasses from the system, allowing trees to grow rapidly and dominate. This then implied that any disturbance (heavy grazing, intense fires, droughts, etc.) that would remove grasses from the system would allow water to be available to trees and as a result trees would grow rapidly, taking over the grassland. However, we now know that young woody plants use the same soil layer as grasses and bush encroachment has been seen where there is little disturbance to the grasses and also in shallow soils where there is little or no separation of root systems. Resource allocation models
David Tillman’s resource allocation model focuses on access to essential resources such as soil nutrients, water, sunlight and space and the way that the savanna plants compete for these. A species that can maintain its population where the resources are least is the one that will outcompete other species and dominate the landscape. However, David Ward acknowledges that the situation will become dynamic where multiple species have different resource needs. For example, changes in one resource, such as light, may cause an increase in one species and not in another.
As an example, shorter plants may be light-limited in an environment in which taller species are nutrientlimited. The ecosystem may become unstable once a species starts to consume enough of a resource to affect the density of another species. Where are we now? There are several other hypotheses put forward, such as the patchdynamic hypothesis and the stateand-transition model, which will not be discussed in detail. What all these models have in common is that they are based on the idea of a savanna as an open system which contains a continuous herbaceous layer and a discontinuous woody layer. However, the most recently published model (Vasquez and others) is the standard contact process model. This is based on the idea of a unit area within a savanna system, which can eventually be filled with trees if the rules of this model are followed. The model sees the system as a grassland phase (absorbing phase) and a woodland phase (active phase) and factors in variables such as weather conditions, average annual rainfall, adult tree longevity and positive and negative local density-dependent tree interactions. It does not, however, take into consideration some crucial factors such as fire and seed dispersal. But, in spite of this the model goes a long way towards solving the savanna problem. The researchers think that it is the external factors that allow the savanna system to switch responsively between or towards each phase – grassland or woodland. Once the grassland phase is reached it may stay there because no tree seedlings are present. However, in real life it is likely that some tree seeds will still be present and a mosaic of grassland and woodland will result if the grass layer is reduced or destroyed. Finally, looking at the various models put forward to try to explain the savanna problem it is becoming clear that fire should not be excluded as a factor, particularly as it is a reality and is the most commonly used management tool, specifically for conservation management. More research is needed on the role of fire in the progression of the system from grassland to woodland and back again. ■ Beka Nxele is a bio-regional planner for Ezemvelo KZN Wildlife and was previously a terrestrial ecologist for Ezemvelo KZN Wildlife and an environmental consultant for the Institute of Natural Resources in Scottsville, PMB.
Bush encroachment by Acacia mellifera, subsp. detinens in a semi-arid savanna in Pniel, Kimberley, Northern Cape. Image: BJ Nxele
Less extensive levels of bush encroachment in a savanna where there are still open pockets of grassland for grazing. Image: BJ Nxele
Savanna systems are normally productive and supportive of biodiversity; a semi-arid savanna in Mkhuze Game Reserve, KwaZulu-Natal. Image: BJ Nxele References Walter, H. Grassland, savanne, und busch der ariden teile Afrikans in ihrer ökologischen. Bedingtheit Jaarboek Wissenschaftliche Botanie 1939; 87: 750 – 860. Tillman, D. Resource Competition and Community Structure. Princeton University Press, Princeton, NJ, 1982. Tillman, D. Secondary succession and the pattern of plant dominance along experimental nitrogen gradients. Ecological Monographs 1987; 57: 189 – 214. Vazquez, F, Lopez C, Calabrese JM and Munoz MA. Dynamic phase coexistence: A simple solution to the “savanna problem”. Journal of Theoretical Biology 2010; 264: 360 – 366.
Quest 6(4) 2010 35
A model of a DNA molecule.
Molecular techniques for genetic modification QUEST looks at how organisms can be genetically modified for selected characteristics
Wheat fields are common in Kenya.
36 Quest 6(4) 2010
ssentially there are two techniques available for the genetic modification of organisms. The most common is recombinant DNA technology, where a DNA molecule with the desired properties is transferred from one organism into the genome of another, and combined to give the second organism that same desired property. But how do scientists deal with the situation when the desired property is not available in another organism? This is where mutation induction comes into play. The technique is founded on the knowledge that the genetic variations found in nature are the result of genotypes recombining or mutating in populations, while continually interacting with environmental forces over time. Chemicals such as sodium azide and ethylmethylsulphonate, or nuclear techniques are then used to artificially induce mutations in organisms. This provides the opportunity to induce attributes that cannot be found in nature or that have been lost over time due to the natural evolution of the organism.
Mutation using ionising radiation The use of ionising radiation to achieve mutation is not a new technology. It dates back to the late 1920s, but it took nearly 30 years to prove that the technology could be useful in plant breeding. Nuclear techniques, while ‘fasttracking’ the natural process of evolution of a plant’s DNA, are still not a ‘quick fix’ and it can take up to 15 years for irradiated seeds to proceed through the characterisation process and the extremely rigorous testing phases before release as a new variety. The technology, however, has proven itself. African success stories Already, using radiation-based techniques, an impressive number of new seed varieties has been generated, with improved qualities including disease resistance; improved lodging resistance; earlier or later maturing times; improved nutritional and cooking qualities; greater heat tolerance; adaptability to adverse soil conditions; and increased yields. Malian scientists, with the assistance
Applications of nuclear techniques in plant breeding.
Lodging is a condition in which the stems of crops bend at or near the surface of the ground, leading to the collapse of the canopy.
of the International Atomic Energy Association (IAEA), have achieved a number of successes with their native sorghum. In 1992 lodging resistance was improved and in 1998 properties were introduced to encourage earlier maturation and increase panicle size – the cluster of flowers and ultimately seeds that grows at the end of the stem – and yield. More recently, efforts to improve resistance to drought have resulted in a further 10% increase in crop yield in field trials, which will go some way to improving production volumes which have not kept pace with the population growth. Following the irradiation of local rice varieties in Mali, the researchers were able to increase yields by more than 15% and develop rice with white colour characteristics that fetches double the price of the original red, resulting in a significant increase in income. Since 2001, Kenyan farmers have been using a mutant wheat variety, developed by the Kenyan Agricultural Research Institute (KARI) in collaboration with the IAEA. The variety is resistant to drought, has high yields and is moderately resistant to wheat rust, a virulent fungus which once threatened to annihilate crops. Today the seed is so popular it is grown on more than 10 000 ha and
Image: Novak, FJ and Brunner, H
White rice – worth double the value of its original red counterpart.
KARI can barely keep pace with demand. Three new varieties of sesame introduced into Egypt are resulting in improved financial returns due to their resistance to disease, high yield and insect resistance. Finger millet and cotton in Zambia, banana in Sudan and cassava in Ghana are further examples of crops that have benefitted substantially from the use of nuclear techniques to improve selected properties. The future of nuclear techniques to improve food crops Success stories surrounding the use of nuclear technology for mutation abound. The resultant increase in production translates into some impressive gains. China estimates the value of the increase in its cereal production at about US$420 million per annum; Pakistan estimates the value of its 40% increase in cotton production at US$20 million per year; and Peru estimates the value of the 50% increase in its barley crop at US$9 million. In translating these production increases into monetary gains, the impact and enormity of the value of nuclear technology in the agricultural environment becomes even more apparent. There remains little doubt that nuclear technology can and should play a significant role in alleviating Africa’s food shortage and ensuring food security.
Sorghum in laboratory trials at the CSIR, South Africa.
Sadly, access to these technologies still remains elusive to developing countries. Enormous capital investments and the concentration of human capital in the development processes have resulted in increased commercial legislation, patents and licensing policies. It is only through specialised agencies, such as the IAEA, the UN Food and Agriculture Organisation (FAO), the UN Educational, Scientific and Cultural Organisation (UNESCO) and the UN Industrial Development Organisation (UNIDO), that appropriate technologies have been identified and training of personnel in developing countries has been undertaken. ■
Quest 6(4) 2010 37
INNOVATION IN NANOTECHNOLOGY IS HELPING TO ADDRESS SOUTH AFRICAN HEALTH CHALLENGES In 2009, it was estimated that 5.7 million South Africans were living with HIV/AIDS and 9.2 million with TB (tuberculosis). These are staggering statistics and a cause for the major focus of government to address these diseases. Nanomedicine is an emerging field of medicine that involves the application of nanotechnology for the diagnosis, treatment and prevention of disease. It promises to have a big impact on the management of diseases such as HIV and TB. One of the six key focus areas recognised in the National Nanotechnology Strategy (NNS), launched in 2005 by the Department of Science and Technology (DST), is health. The aim of the NNS is to coordinate nano research and development around the six key focus areas, and includes support for long-term nanoscience research, and the development of people and facilities relating to the field. Nanotechnology has been hailed as the “leading technology of the 21st century”. It is an enabling technology, recognised as an important tool for industrial development and as a means to improve the lives of ordinary people. Nanotechnology has enriched and in some cases altered our fundamental understanding of the material world. Its impact will be far-reaching and is set to affect most fields including health and medicine, energy, information technology, material and
manufacturing, the environment, transportation, national security and space exploration. Nanotechnology is the act of manipulating material at very tiny (nano) scales, essentially at the level of atoms and molecules. At these small sizes, the normal rules of physics and chemistry no longer apply and materials often display unique and surprising properties. In the field of health, nanotechnology is being used in: ■ Diagnostics: Nanotechnology promises quick, early and accurate detection of diseases such as malaria, cholera, HIV/AIDS and even cancer. Portable, but highly sensitive point-of-care test kits are under development by scientists at Mintek which will offer all the diagnostic functions of a medical laboratory. Depending on how they are designed and the intended application, the hand-held kits could be used to test for viruses, bacteria or hormones. Thus they will be able to test – simply and quickly – for infectious diseases such as malaria, cholera, HIV/AIDS and other sexually-transmitted infections, and even cancer. Also known as the “lab-on-a-chip” because of their ability to emulate the services of a complete medical laboratory, these inexpensive, hand-held diagnostic kits can pick up the presence of several pathogens at once and could be used for wide-ranging screening in remote clinics. According to Robert Tshikudo, head of nanotechnology at Mintek, research on using the kits for infectious diseases is in the “final stages” and
the ultimate goal is to make the kits available to government hospitals and clinics to reach those who need it. ■ Biomedical Imaging: Nanotechnology applications are in development that will radically improve medical imaging techniques. For example, gold and silver nanoparticles have optical properties which make them extremely effective as contrast agents. Quantum dots which are brighter than organic dyes and need only one light source for excitation, when used in conjunction with magnetic resonance imaging, can produce exceptional images of tumour sites. ■ Therapeutics: • Targeted Drug Delivery Systems: Nanostructures can be used to recognise diseased cells and to deliver drugs to the affected areas to combat cancerous tumours, for example, without harming healthy cells. In obesity, nanoparticles can target and inhibit the growth of fat deposits. • Slow-release drug therapy: Research shows that nano-sized biodegradable polymer capsules containing drugs for tuberculosis treatment are effectively taken up by the body’s cells. The effect is a slower release of the drug into the body and a reduction in the frequency with which TB patients need to take their medication. In countries where drugs are not readily available and compliance is low, the technology holds great potential for increased drug compliance and a reduced chance of the development of drug resistance. Scientists at CSIR are working on this. The same concept has application in delivery of drugs for other diseases such as HIV/ AIDS and malaria.
magnetic wavelength or optical properties. They absorb light and heat up the surrounding area, killing the cancer cells. In both diagnosis and treatment, nanotechnology holds the key to revolutionise health care, particularly in developing countries where access to health care is still a challenge for millions of people living in remote areas. Some drawbacks of nanotechnology may exist. There are concerns that the same properties (size, shape, reactivity, etc.) that make nanoparticles so useful could also make them harmful to the environment and toxic to humans, for example, if they accumulate in drinking water supplies and the food chain. These concerns are exacerbated by the current poor understanding of the fate and behaviour of nanoparticles in humans and the environment. Risk assessment research is crucial for establishing the potential impacts of nanoparticles upon human health and the environment: the technology’s benefits must be balanced against any unintended consequences. This is a massive challenge, since it is very difficult to monitor the possible impact of the huge volume of diverse nanoparticles being produced and used in different products and applications. Although there are currently no nanotechnology-specific regulations in South Africa due to the relative infancy of this emerging technology, the government, through the DST, is funding a research platform to investigate the environmental, safety and health aspects of nanotechnology.
The Nanotechnology Public Engagement Programme (NPEP) is an initiative funded by the Department of Science and Technology (DST) and implemented by the South African Agency for Science and Technology Advancement (SAASTA), a business unit of the National Research Foundation (NRF). Launched in early 2008, the NPEP aims to promote credible, fact-based understanding of nanotechnology through awareness, dialogue and education to enable informed decision making on nanotechnology innovations to improve the quality of life.
The objectives of the Nanotechnology Public Engagement Programme are to: ■ Create awareness around nanotechnology; ■ Educate the public on, and enhance their understanding of nanotechnology; ■ Enable and stimulate meaningful public debate around nanotechnology; ■ Stimulate interest in nanotechnology and nanoscience as a career in order to ensure long term capacity building in the field; and ■ Get industry involved in the development of nanotechnology and take the lead in nanotechnology innovation.
■ Photothermal and Hypothermal Destruction of Cancer: Some nanoparticles, such as gold, possess therapeutic properties based on their South African Agency for Science and Technology Advancement (SAASTA) Tel: 012 392 9300 Fax: 012 320 7803 Web: www.saasta.ac.za
Sky watching Sky Guide Africa South: Astronomical Handbook for Southern Africa 2011. Compiled and edited by Wayne Trow, assisted by Maciej Soltynski. (Cape Town. Astronomical Society of Southern Africa and Random House Struik. 2010.) This small book is an invaluable and practical resource for anyone with a real interest in the night skies of southern Africa. The book is put together by the Astronomical Society of Southern Africa for use by the novice, amateur and professional astronomer alike. It is packed with information about the Sun, the Moon, the planets, comets, meteors and bright stars. The information is clear and accessible and accompanied by diagrams. The information is specifically about the year 2011 and will tell you about the movement of the planets, when eclipses will occur, the dates of meteor showers and clearly presented star charts so that you can identify stars and constellations. There is a section on the history of astronomy in southern Africa and another on contemporary astronomy in South Africa, along with information about different astronomy clubs and societies, useful web sites and a glossary.
dreamed about. Game Parks of South Africa features 20 of the country’s best reserves – and the most well-known. Beautifully illustrated by Gerald Hinde’s photographs, the book takes you from the Kruger National Park, across to the Kgalagadi Transfrontier Park, through the Golden Gate Highlands National Park through the Karoo to the Table Mountain National Park, to mention only a few. Complementing Game Parks of South Africa is Carol Polich’s wonderful collection of wildlife photographs in Wildlife of Southern Africa. This is no mere book of photographs, but provides insight into the behaviour and idiosyncrasies of southern Africa’s spectacular wildlife. It contains more than 90 full-colour photographs of big game and other interesting creatures, with captions that explain behaviour and biology.
Conservation in the raw
Game Parks of South Africa. By Gerald Hinde. (Cape Town. Random House Struik. 2010.)
Nine Lives: Memoirs of a Maverick Conservationist. By John Varty. (Cape Town. Zebra Press. 2010.)
Wildlife of Southern Africa. By Carol Polich. (Cape Town. Random House Struik. 2010.)
For me, the big cats are, without a doubt, the best of all the wild creatures that I love (apologies to my wonderful cat family at home!). I can look at photographs, watch film footage, cry over their misfortunes and rail against
These two little books are ideal for throwing into the car before you embark on that wildlife holiday you have always
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the cruelty with which they are often treated by humankind. I think that John Varty is much the same. This wonderful book is an account of his life in conservation, starting from his childhood experiences as a hunter and from there chronically his progression to environmentalist and film maker. He has lived an astonishing and enviable life. His family co-owns the game farm Londolozi, which is renowned for its work with leopards – secretive and nocturnal. Varty was privileged to share friendship with these wonderful creatures. His work as a film maker brought him into contact with many famous people, including Nelson Mandela. The book is a romp through his ‘maverick’ approach to conservation, near-death experiences both with wild animals and a near-fatal helicopter crash, as well as poachers, drug smugglers and mercenaries. It is, as the fly leaf says, ‘a thrilling and fascinating story’. Varty is now enagaged in a controversial, but globally known, tiger conservation project in the Free State, where he is raising this highly endangered big cat in the hopes of preserving the species. Birds across Africa Birds of Africa south of the Sahara. 2nd ed. By Ian Sinclair and Peter Ryan. (Cape Town. Random House Struik. 2010.) This is not a pocket guide, but any dedicated bird watcher would be more than happy to carry it in his or her backpack when bird watching across
The best of both worlds Mountains in the Sea: A Celebration of the Table Mountain National Park. By John Yeld and Martine Barker. (Cape Town. South African National Parks in association with Africa Geographic. 2010.) this vast continent. Ian Sinclair and Peter Ryan are arguably two of the best known ‘birders’ in Africa – at least of the current generation – and once again they have done an excellent job in this book. And, I would imagine, knowing them both as I do, they have seen most of the species in the book! Birds of Africa is a field guide, but the scope of the book makes it far more than that. It is a comprehensive account of the species found across the continent, both common and rare, and the amount of work that went into putting this book together must have been quite overwhelming at times. There is a comprehensive introduction, covering the geographical area, species accounts, identification, habitats and status. The way in which the range maps were put together is described, as are species order, taxonomy and common names. The book is illustrated with plates by Normal Arlott, Peter Hayman and Alan Harris in a distinctive style that anyone who regularly uses these field guides will recognise. The new edition contains around 500 new images and 400 updated maps, along with a fully revised text, which provides the latest information available. There are 2 129 species covered, with an additional 101 vagrants described briefly. Changes in taxonomy have also been included and the distribution maps are based on the latest surveys. The species descriptions give precise identification features, highlighting differences between similar species, as well as reporting habitat, status and calls. A must for any serious birder in Africa.
Everything you have ever wanted to know… Factopedia: Fascinating facts about South Africa and the world. (Cape Town. Zebra Press. 2010.) This book is not only about science, but there is enough in it about amazing scientific facts to make it worthy of a review in QUEST. Do you want to know the most abundant elements in the universe, the planets by size, the stars closest to Earth and the ten first in space? Look no further than the Space section of this book. You can see the Earth at a glance – the layers of the atmosphere, the oceans of the world by size, population information (including that for South Africa’s provinces), extreme weather around the world, the world’s largest meteorite craters – the list goes on. Find out about poisonous plants and mushrooms in South Africa, the indigenous flowers most often found in South African gardens and the largest forests in South Africa. Animals are not left out with a range of fascinating facts about South African animals and those in the rest of the world. On the human interest side there is a comprehensive section on the body and health as well as a interesting section on food and drink – which of course pertains directly to human health! Outside the sphere of science there are sections on politics, law and order, business and wealth, technology and the internet, arts and culture, literature and education, entertainment and sport. Enjoy!
This is a truly beautiful book, although of course I am biased, living as I do on the edge of Table Mountain National Park. In Nelson Mandela’s words, ‘For centuries Table Mountain has been a symbol of our mother city, Cape Town. During the many years of incarceration on Robben Island we often looked across Table Bay at the magnificent silhouette of Table Mountain… To us on Robben Island, Table Mountain was a beacon of hope.’ What wonderful words to describe what is arguably one of the most spectactular places in the world. The mountain chain that contains Table Mountain (or Hoeri’kwaggo or Sea Mountain, to give it its Khoe-San name) runs some 40 km along the spine of the Cape Peninsula between Cape Town and Cape Point. Much of this mountain area is conserved within the Table Mountain National Park, which is the most visited of all South Africa’s national parks and the most visited protected area in Africa. Table Mountain’s park protects one of the most biodiverse regions of the world. It is a key component of the Cape Floristic Region World Heritage Site that was declared by UNESCO in 2004. The book is lavishly illustrated by photographs from a variety of different sources and includes the flora, fauna and of course, the mountain chain itself. The contents range from the geological and social history of the area, to the ecosystem of the mountain. There is a description of the recently set up Hoerikwaggo Trail and the final chapter uses photographs to show the many and varied activities available on the mountain chain as well as the range of different habitats, many of them residential areas, that lie along this coast. This book is a fitting tribute to this magnificent part of the world.
Quest 6(4) 2010 41
Diary of events Q Shows and exhibitions Iziko Planetarium, Cape Town Between now and January Especially for children Silly Solly and the Shooting Stars Solly Snail wants to be chosen for his garden's soccer team and thinks up ways to become a speedier snail, so that he will be chosen. He decides to ask a shooting star to help him, but does his plan work and will he be chosen for his garden's soccer team? Join him on his quest and find out for yourself! 11 December – 18 January Monday to Friday – 11:00 and 12:00 • Saturday – 12:00 (excluding 25 December) • Sunday – 12:00 PLUS 22, 23, 29 and 30 January – 12:00 Especially for children aged 5-12
For teenagers and adults Living Inside the Cosmic Egg On a clear night you cannot see forever, even with the most powerful telescope imaginable. The observable universe ends abruptly at an opaque wall, created by the conditions that followed the big bang beginning. That wall appears to surround us – forming the shell of a hollow sphere, with us at the centre – a Cosmic Egg that contains everything of our universe. Generally dark inside – at least to normal eyesight – it is populated with billions of galaxies, each a gigantic city of stars in itself, each star probably having its own solar system. Starts 11 December Monday to Friday – 14:00 • Tuesday evening – 20:00 (and sky talk) • Saturday – 14:30 (excluding 25 December) • Sunday – 14:30 Suitable for teenagers and adults
A Basic Guide to Stargazing This presentation will give you a basic understanding of the night sky and how it changes through the year. We introduce some easily recognisable constellations, explain the nature of stars and the galaxy in which we live and give basic information in using binoculars and small telescopes. 13 December – 18 January Monday to Friday – 13:00 Suitable for teenagers and adults Planetarium entrance fees Adults: R20.00; Children: R6.00; Adults (children’s show only): R10.00; SA Pensioners and Students (with cards): R8.00 The Planetarium reserves the right to change or cancel advertised shows without prior notice. The Iziko Planetarium is closed for maintenance on the first Monday of the month, excluding school holidays.
Talks, outings and courses The Cape Bird Club Junior Programme All juniors, members or not, who are interested in birds are welcome on the first Sunday of
42 Quest 6(4) 2010
each month. Binoculars are essential equipment. Transport is not provided so grandparents and parents are encouraged to come along with their children. All school children are welcome, whether they are members or not, but the programme is not really intended for preschool children. All outings last for 1.5 hours unless stated. Booking is essential at least 24 hours ahead. Contact Heather Howell, the co-ordinator, for all bookings 021 788 1574. Outings in early 2011 There will be no Rondevlei outing this month as the first Saturday falls on New Year’s Day. Wed 5 January. Die Oog Bird Sanctuary. Co-ordinator Frank Hallett on 021 685 7465 Sun 16 January. Rondekuil and Goedeontmoeting, Durbanville area. Leader Gerald Wingate and Jurie Fouruie. Co-ordinator Ann Gray on 021 713 1231 or 083 311 1140 Thur 3 February. Koeberg Nature Reserve. Leader Otto Schmidt on 021 674 2381. Co-ordinator Frank Hallett on 021 685 7465 Sat 05 February. Rondevlei. Leader Ann Koeslag on 021 762 5347 Sun 20 February. West Coast National Park. Leader Vernon Head on 076 569 1389
Witwatersrand Bird Club Saturday outing/Rolfe’s Pan Saturday 8 January 2011. Meet: 07:00 in front of the gates of Thempelihe Equipment. Leader: Val Odendaal (082 921 5019). Sunday outing/Elandsvlei Sunday 9 January 2011. After CWACing at Rolfe’s Pan you can spend the night of Saturday 8 January in the accommodation at Elandsvlei. Please reserve your accommodation on either email@example.com or 011 782 7267. GPS Co-ordinates: S25.99567 E 28.46592 Meet: 06:00 at main pan Leader: Val Odendaal (082 921 5019). Wednesday afternoon outing/Delta Park Wednesday 12 January 2011. The park offers a variety of garden and woodland species as well as a number of waterbirds at this, Wits Bird Club’s local patch. Geoff is sure to find some unbelievable birds coming in to roost in the late afternoon. Meet: 15:00 in car park. Beat the traffic! Leader: Geoff Lockwood (082 346 2597). Sunday outing/Suikerbosrand Nature Reserve Sunday 16 January 2011. Enter the reserve and meet in the parking lot of the Diepkloof Visitors Centre. Cost: Entrance fee applicable. Meet: 07:00 in the parking lot Leader: Lance Robinson (082 927 9785). Now it’s your turn – Birding By WBC Members In 2010 20 January 2011 • 19:15 - 21:30 Birding By WBC Members In 2010. Come share your best birding experiences of 2010 with us. We are inviting members to a ‘show-and-tell’ evening with each speaker being allocated 5-7 minutes. If you are interested in sharing with us, please submit your names to Lauraine before the 15 December 2010 or alternatively, to Marguerite Waite at marguerite@mtnloaded. co.za – 083 920 4372. Saturday outing/Vaalkop Dam 22 January 2011 • 07:30 - 15:30 Please advise your attendance for the CWAC by no later than 18:00 on Friday 21 January Leader: Lance Robinson (082 927 9785).
Annual woodland census/Nylsvley weekend census 28 January 2011 to 30 January 2011 FRIENDS OF NYLSVLEY - Knowledgeable and keen birders are invited to help count Nylsvley’s Woodland Bush Birds. Meet: From 16:00 on Friday for supper, route confirmation, census training and bird ID review. Saturday 06:00. Census followed by brunch sponsored by the Wits Bird Club. Accommodation and other meals by arrangement. Attendees are invited to stay over in case of bad weather when the census will be done on the Sunday instead. Bookings: Marion Dunkeld-Mengell friendsnylsvley@mweb. co.za Tel/fax: 012 667 2183.
Diarise 31 January 2011 World Leprosy Day is observed internationally on 31 January or its nearest Sunday to increase the public awareness of the Leprosy or Hansen's Disease. This day was chosen in commemoration of the death of Gandhi, the leader of India, who understood the importance of leprosy. Leprosy is one of the oldest recorded diseases in the world. It is an infectious chronic disease that targets the nervous system, especially the nerves in the cooler parts of the body – the hands, feet, and face.
2 February 2011 World Wetlands Day occurs on 2 February, every year.It marks the date of the signing of the Convention on Wetlands, called the Ramsar Convention, on 2 February 1971, in the Iranian city of Ramsar on the shores of the Caspian Sea. WWD was celebrated for the first time in 1997 and made an encouraging beginning. Each year, government agencies, non-governmental organisations, and groups of citizens at all levels of the community have taken advantage of the opportunity to undertake actions aimed at raising public awareness of wetland values and benefits in general and the Ramsar Convention in particular. From 1997 to 2007, the Convention’s web site has posted reports from more than 95 countries of WWD activities of all sizes and shapes, from lectures and seminars, nature walks, children’s art contests, sampan races, and community clean-up days, to radio and television interviews and letters to newspapers, to the launch of new wetland policies, new Ramsar sites, and new programmes at the national level.
4 February 2011 World Cancer Day is marked on 4 February to raise awareness of cancer and to encourage its prevention, detection, and treatment. It is led by the International Union Against Cancer (UICC), a global consortium of more than 350 cancerfighting organisations in over 100 countries. World Cancer Day targets the public through global communications marking, and encourages policy makers and UICC member organisations to make cancer a political priority.
12 February 2011 Darwin Day is a recently instituted celebration intended to commemorate the anniversary of the birth of Charles Darwin on 12 February, 1809. The day is used to highlight Darwin's contribution to science and to promote science in general.
Q ASSAf News
Biodiversity takes centre stage The first national Young Scientists' Conference in South Africa took place just outside Pretoria on October 12 and 13. It was an initiative of the Academy of Science of South Africa (ASSAf), in partnership with the department of science and technology and the National Research Foundation (NRF). The conference, titled ‘Biodiversity in Focus: Exploring the Opportunities for South Africa's Future’, was attended by more than 90 young scientists from 13 universities and eight science councils, as well as members of the government and private sector. The conference started with short welcome addresses by Professor Robin Crewe, the ASSAf president, Dr Phil Mjwara, the director general of the department, and Dr Albert van Jaarsveld, the president of the NRF. As the country's official national science academy with a membership of about 340 members, elected on the basis of a lifetime achievement of excellence and scholarship, ASSAf is aware of its role in fostering the next generation of young scientists. The department is investing heavily in the science, technology and innovation sector. Through the NRF it is apparent that there is a commitment to increase funding for young scientists, which will enable them to prepare themselves for a scientific career. The keynote address on ‘Biodiversity Science in South Africa’ by Dr Belinda Reyers of the Council for Scientific and Industrial Research emphasised the outstanding opportunities for biodiversity scientists presented by the unique natural laboratory in the country. South Africa has three biodiversity hotspots: the Succulent Karoo, the Cape Floristic Region and the MaputalandPondoland-Albany region. Compared with the total of four hotspots in North and Central America and five in the whole of South America, South Africa possesses a significant portion of global biodiversity in relation to its total land area. The country also has a long history of biodiversity science, not always a characteristic of other developing countries, and so has an excellent research foundation in the field. The conference drew participants in other fields, including engineering, anthropology and economics, which demonstrated that biodiversity science is not the sole preserve of biological scientists and its future strength lies in a multidisciplinary approach. Topics included the use of local belief systems and values in conserving biocultural diversity, the microbial biodiversity hotspots in South Africa’s deep mines, the value of biodiversity for modern drug development and the impact of climate change on biodiversity. The conference began the morning after the launch of The PhD Study, an ASSAf report drawing attention to the paucity of South African PhDs compared with other developing economies. But if the attendance, quality of presentations and enthusiasm evident at this conference are indicators of the future health of biodiversity science in South Africa, then there is cause for optimism.
Not all the young scientists at the conference were part of well-established research groups – many attended as individuals and as single participants from their institutions. It is hoped that the networking opportunities provided will stand them in good stead as they complete their studies and seek opportunities in the workplace.
Recipients of the annual ASSAf awards, from left, Dr Mohlopheni Jackson Marakalala from the Institute of Infectious Diseases and Molecular Medicine, who was awarded the Sydney Brenner Fellowship Award and Professors Diane Hildebrandt from the University of the Witwatersrand and Eugene T Cloete from Stellenbosch University, who both received the Science-for-Society Gold Award.
ASSAf recognises top scientists ASSAf (the Academy of Science of South Africa) recently recognised three top South African scientists at its prestigious Annual Awards Ceremony held in Pretoria. Professors Diane Hildebrandt from the University of the Witwatersrand and Eugene T Cloete from Stellenbosch University, both received the Sciencefor-Society Gold Award while Dr Mohlopheni Jackson Marakalala from the Institute of Infectious Diseases and Molecular Medicine was awarded the Sydney Brenner Fellowship Award. ASSAf annually awards up to two ASSAf Science-for-Society Gold Medals for outstanding achievement in scientific thinking to the benefit of society. Hildebrandt is a SARChI Professor of Sustainable Process Engineering and Director of the Centre of Material and Process Synthesis (COMPS) at the University of the Witwatersrand, Johannesburg, South Africa. She obtained her BSc and PhD in Engineering and Chemical Engineering from the University of the Witwatersrand. Hildebrandt has authored or co-authored over 80 scientific papers and has received 306 citations in the past three years. She is the first female chemical engineer to have been awarded an A-rating by South Africa’s National Research Foundation. Hildebrandt’s research over the last 25 years has focused on improving the efficiency of equipment and chemical processes. Her work is of particular importance for Africa and is being used to help solve Africa’s energy and food needs. She has
supervised and co-supervised 55 postgraduate students who have received master's and PhD degrees in Engineering and Science. She currently supervises 40 postgraduate students of whom about half are South African and the other half from the rest of Africa. What is remarkable is that these students are funded mostly by the COMPS group that is directed by Hildebrandt. The group raises more than1.5 million rand annually to supply bursaries to these students. Cloete is currently the Dean of the Faculty of Science at Stellenbosch University. He was formerly at the University of Pretoria as Chair of the School for Biology, Head of the Department of Microbiology and Plant Pathology and Director of the UP Water Institute. He has made many notable contributions to the field of microbiology, both in South Africa and elsewhere. His career has also been distinguished by the fact that he applied much of his research in a policy context both nationally and internationally. Much of this policy work has concerned reducing the rates and impacts of water poverty identified as one of the Millennium Development Goals and also as one of the key threats to achievement these goals. Recognition of his scientific achievements in the field of science and policy generally has been reflected by his substantial research outputs, and invitations to serve on the editorial boards of some of the world’s most prestigious journals. Marakalala, who received the Sydney Brenner Fellowship award, was born in Mokopane (formerly Potgietersrus) in 1979, and obtained BSc and BSc (Hons) degrees in biochemistry at the University of Limpopo in 2003. As a Canon Collins Scholar he commenced an MSc Med in 2004 at the University of Cape Town with Prof Daan Steenkamp in the Division of Chemical Pathology. For his project, which was upgraded to a PhD in 2006, Marakalala worked on drug development for TB and MDR-TB, with a focus on the inhibition of essential enzymes in the biosynthesis of Mycothiol, the major antioxidant in Mycobacterium tuberculosis. His PhD was conferred the Bronte Steward award for the most meritorious thesis submitted by a doctoral student in 2008. He then joined the Institute of Infectious Diseases and Molecular Medicine, Division of Immunology, in August 2008 as a postdoctoral fellow under the mentorship of Prof Gordon Brown, where he is investigating the role of Dectin-1 in innate immunity to various infectious diseases, including tuberculosis, fungal infections, Staphylococcus aureus and recently, the role of this receptor and beta-glucans in anticancer immunity. The Sydney Brenner award was established when Dr Sydney Brenner donated a portion of his 2002 Nobel Prize to ASSAf to permit ASSAf (in partnership with the United States National Academy of Sciences) to offer a prestigious postdoctoral Fellowship for research to be undertaken in South Africa over two years by an outstanding young scientist. Brenner mentors the Fellows during and after tenure of the Fellowship. The Oppenheimer Memorial Trust has donated funds for a second Fellowship.
Quest 6(4) 2010 43
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Q Back page science Volcanic eruptions affect rainfall over Asian monsoon region Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air, and some suspect that extended ‘volcanic winters’ from gigantic eruptions helped to kill off dinosaurs and Neanderthals. In the summer following Indonesia's 1815 Tambora eruption, frost damaged crops as far away as New England in the US, and the 1991 eruption of the Philippines' Mount Pinatubo lowered average global temperatures by 0.7° C – enough to mask the effects of greenhouse gases for about a year. Now, in research funded by the National Science Foundation’s (NSF) Division of Atmospheric and Geospace Sciences, scientists have discovered that eruptions also affect rainfall over the Asian monsoon region, where seasonal storms water crops for nearly half of Earth's population. Large explosive eruptions send up sulphur compounds that turn into tiny sulphate particles high in the atmosphere, where they deflect solar radiation, and the resulting cooling on Earth's surface can last for months or years. As for rainfall, in the simplest models, lowered temperatures decrease evaporation of water from the surface to the air, and less water vapour translates to less rain. Ultimately, such studies should help scientists refine models of how natural and man-made forces might act together to shift weather patterns – a vital question for all areas of the world. Source: National Science Foundation
Sun. This is surprising, and that much mass means that several theoretical models for the internal composition of neutron stars now are ruled out,’ said Paul Demorest, of the National Radio Astronomy Observatory (NRAO). ‘This mass measurement also has implications for our understanding of all matter at extremely high densities and many details of nuclear physics,’ he added. Neutron stars are the super-dense ‘corpses’ of massive stars that have exploded as supernovae. With all their mass packed into a sphere the size of a small city, their protons and electrons are crushed together into neutrons. A neutron star can be several times denser than an atomic nucleus, and a thimbleful of neutron-star material would weigh more than 500 million tons. This tremendous density makes neutron stars an ideal natural ‘laboratory’ for studying the most dense and exotic states of matter known to physics. The neutron star is a pulsar, emitting lighthouse-like beams of radio waves that sweep through space as it rotates. This pulsar, called PSR J1614-2230, spins 317 times per second, and the companion completes an orbit in just less than nine days. The pair, some 3 000 lightyears distant, are in an orbit seen almost exactly edge-on from Earth. That orientation was the key to making the mass measurement. Source: National Radio Astronomy Observatory
Pulses from neutron star (rear) are slowed as they pass near foreground white dwarf. This effect allowed astronomers to measure masses of the system. Image: Bill Saxton, NRAO/AUI/NSF Volcanic eruptions, such as this 18 km-high plume from one of a series of eruptions in 1991 at Mount Pinatubo in the Philippines, may affect Asian monsoon rainfall; the seasonal storms water critical crops. Image: Image USGS
Astronomers discover most massive neutron star yet known Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics. ‘This neutron star is twice as massive as our
acids in the virus’ proteins. In contrast, mosaic vaccines are composed of many sets of synthetic, computer-generated sequences of proteins that can prompt the immune system to respond to a wide variety of circulating HIV strains. Such vaccines have already been studied in animals and have shown some success in enhancing the breadth of immune responses. Source: Los Alamos National Laboratory
Scanning electron micrograph of HIV-1 virus budding (in green) from cultured lymphocyte. Image: Los Alamos National Laboratory
The liquid crystal is dazzling A dazzling array of unusual patterns can be found in a thin, liquid crystalline film seen through a polarising microscope. A crystalline substance is marked by an orderly arrangement of molecules overall, but distortions can arise from point to point, resulting in striking visual forms such as those seen here. In the liquid crystal shown in the picture, called a nematic fluid, there are rod-like, elongated molecules that are free to move around, but tend to be parallel to each other. Their average orientation, however, changes from place to place in the film, which is only a thousandth of a millimetre thick. Source: World Science, http://www.world-science.net
Consortium to design human trials of mosaic HIV vaccine Los Alamos National Laboratory researcher Bette Korber is part of an international team of investigators working to design and implement the first human trial of a mosaic HIV vaccine candidate. The vaccine represents a novel strategy for fighting the virus that causes AIDS by attempting to address one of the most daunting challenges in HIV vaccine design: the virus’s extensive genetic diversity. Traditional HIV vaccines are designed to stimulate the body’s immune system to recognise naturally occurring stretches of specific amino
A striking arrangement of liquid crystals. Image: Oleg D. Lavrentovich, Kent State University
MIND-BOGGLING MATHS PUZZLE FOR Q uest READERS Q uest Maths Puzzle no. 15 A corner café requires that you pay a deposit on all bottles you purchase and when you return your bottles, you will receive your deposit back. If you buy a bottle of soda for R2 and the deposit is R1.60 less than the actual cost of the soda, how much was the deposit?
The winner of Maths Puzzle no. 14 was Madelein van Straaten of Sasolburg Answer to Maths Puzzle no. 14: First man 1 and man 2 walk across the bridge. This takes 2 minutes. After this, man 1 walks back with the flashlight. This takes 1 minute. Then man 3 and man 4 walk across the bridge. This takes 10 minutes. After this, man 2 walks back with the flashlight. This takes 2 minutes. Then man 1 and man 2 walk across the bridge. This takes 2 minutes as before. In total: 2+1+10+2+2=17 minutes.
Win a prize! Send us your answer (fax, e-mail or snail-mail) together with your name and contact details by 15:00 on Friday, 21 January 2011. The first correct entry that we open will be the lucky winner. We’ll send you a cool Truly Scientific calculator! Mark your answer ‘Quest Maths Puzzle no. 15’ and send it to: Quest Maths Puzzle, Living Maths, P.O. Box 478, Green Point 8051. Fax: 0866 710 953. E-mail: firstname.lastname@example.org. For more on Living Maths, phone (083) 308 3883 and visit www.livingmaths.com.
Quest 6(4) 2010 45
The Safety Standards and Regulatory Practices regulation published under the National Nuclear Regulator Act (Act No. 47 of 1999), provides detailed technical rules to regulate the conduct of persons engaged in activities related to the use of and exposure to fissionable materials, ionizing radiation and natural sources of radiation. The Safety Standards and Regulatory Practices regulation includes: • Risk criteria which address the mortality risk from nuclear energy and radiation to the present and future generation; • Acceptable radiation dose limits for exposure of people (individually and collectively) and the environment arising under normal operations and as a consequence of nuclear incidents; • Fundamental safety principles to ensure that the activities relating to the construction, operation and decommissioning of facilities are conducted to achieve the highest standards of safety that can be reasonably achieved; and • Emergency Preparedness and Response planning to mitigate the consequences of nuclear events and incidents.
For the protection of persons, property and the environment against nuclear damage
Contact Postal Address: PO Box 7016, Centurion, 0046 Physical Address: Centurion Office Park, Block A, 2nd Floor, Cnr Embankment & Hendrik Verwoerd Drive, Centurion, 0157 Tel: +27 12 674 7100, Fax: +27 12 663 5513, Email: email@example.com, Website: www.nnr.co.za