Science for South Africa
Probing our cosmic past
Volume 10 | Number 1 | 2014
The search for Earth-like planets Clouds: the enigma in our skies The Age of the Anthropocene: climate change Making cars faster
Acad e my O f Sci e n ce O f South Afri ca
Join Hannah and our young astronomer, Naledi, as they N discover more about the SKA project in the Karoo in the next edition of HAN our cartoon series: Mission MeerKAT. In this, the fourth edition of Mission MeerKAT, Naledi and Hannah explain the relationship between SKA South Africa and SKA Australia, and how important this partnership is to uncovering the secrets of the universe.
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If you missed the previous issues, you can find them on http://www. ska.ac.za/education/index.php.
Mission MeerKAT: Working Together is available online at http://www.ska.ac.za/download/ mission_meerkat4_eng.pdf.
LD, ONE S KY
Is discovering the universe for you? If Mathematics and Natural Science are subjects that excite you, why not look to the stars for a career in engineering, technology or astrophysics? The SKA SA Project invests in developing skills for MeerKAT and the SKA through its dedicated Human Capacity Development Programme. Already, close to 500 people, ranging from artisans to postgraduate students and postdoctoral fellows, have already received bursaries and grants. Find out more at www.ska.ac.za/students
COOL FACTS ABOUT THE SKA The data collected by the SKA in a 24-hour period, would take nearly two million years to play back on an iPod. The SKA will generate enough raw data every day to fill 15 million 64GB iPods. The SKA central computer will have the processing power of about one hundred million PCs. The SKA will use enough optical fibre to wrap twice around the Earth. The dishes of the SKA will produce 10 times the current global internet traffic. The aperture arrays will produce more than 100 times the current global internet traffic.
Photo credit PHOTOWISE
The SKA super-computer will perform 1018 (1 000 000 000 000 000 000) operations per second â€“ equivalent to the number of stars in three million Milky Way-size galaxies. This is needed to process all the data that the SKA will produce. (source: www.skatelescope.org)
Keep up to date with the latest news and views from the SKA SA. Follow us on Facebook â€“ www. facebook.com/SKASOUTHAFRICA
Department: Science and Technology REPUBLIC OF SOUTH AFRICA
ontents Volume 10 | Number 1 | 2014
Cover Stories 3 Probing our cosmic past
PAPER – an SKA project – takes us to the edge of the Universe
6 Exoplanets – the search for Earth-like planets
Quest investigates the Kepler Space Mission
14 Clouds – an enigma in the climate puzzle
Mike Lucas explains the role of clouds in climate science
18 This is indeed the Age of the Anthropocene
A brief look at the latest IPCC report on climate change
22 How to make your car faster:
unichip and performance exhaust
Androniki Pouris tells us how to go fast for less
10 The latest from the South African Space Agency
SANSA keep us up-to-date on South African space science
24 Lion diaries
Andrew Zaloumis tells the story of lions in iSimangaliso
26 Lake St Lucia on the road to recoveery
The new iSimangaliso management strategy for Lake St Lucia is working
14 10 24
Jellyfish drones coming? • New upgrade gives SANSA the international edge
31 A tribute to Nelson Rolihlala Mandela 33 News
Bio-pesticides: the bigger picture • Cheating at Comrades
34 ASSAf news 35 News
Our inner Neanderthal
36 Books 38 Subscription 40 Back page science • Mathematics puzzle
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Science for South AfricA
Probing our cosmic past
Volume 10 | Number 1 | 2014
The search for Earth-like planets Clouds: the enigma in our skies The Age of the Anthropocene: climate change Making cars faster
AcAd e my o f Sci e n ce o f South Afri cA
Images: Wikimedia Commons, www.spacetelescope.org
Editor Dr Bridget Farham Editorial Board Roseanne Diab (EO: ASSAf) (Chair) John Butler-Adam (South African Journal of Science) Anusuya Chinsamy-Turan (University of Cape Town) Neil Eddy (Wynberg Boys High School) George Ellis (University of Cape Town) Kevin Govender (SAAO) Himla Soodyall (University of Witwatersrand) Penny Vinjevold (Western Cape Education Department) Correspondence and enquiries The Editor PO Box 663, Noordhoek 7979 Tel.: (021) 789 2331 Fax: 0866 718022 e-mail: email@example.com 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: firstname.lastname@example.org Subscription enquiries and back issues Phathu Nemushungwa Tel.: (012) 349 6624 e-mail: email@example.com Copyright © 2014 Academy of Science of South Africa
Published by the Academy of Science of South Africa (ASSAf) PO Box 72135, Lynnwood Ridge 0040, South Africa
Permissions Fax: 0866 718022 e-mail: firstname.lastname@example.org Subscription rates (4 issues and postage) (For other countries, see subscription form) Individuals/Institutions – R100.00 Students/schoolgoers – R50.00 Design and layout Creating Ripples Graphic Design Illustrations James Whitelaw Printing Seriti Printing Pty Ltd
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Into the space T
his first edition of Quest for 2014 is the edition that is distributed at SciFest Africa and the theme this year is ‘Into the space’. Let’s investigate what ‘space’ means in science and mathematics. The definition of space from Wikipedia reads, ‘Space is the boundless three-dimensional extent in which objects and events have relative position and direction’. The article explains that physical space is thought of as three linear dimensions – but that modern physics also includes time, to arrive at a four-dimensional continuum called ‘spacetime’. The conceptualisation of ‘space’ started a long time ago – around 400 BC when Plato and other ancient Greeks started to think about what the Greeks called khora – space. Out of these reflections on the nature of space – initially philosophical – came classical mathematics, geometry and classical mechanics. The father of modern physics, Isaac Newton (1642 - 1727) thought that space was absolute – space existed permanently and was present regardless of whether or not there was any matter in the space. Other early physicists, who were also philosophers, thought that space was a collection of relations between objects – these relationships are factors of the distance and direction of each of these objects from each other. It was not until the 19th and 20th centuries that mathematicians started to think of space as curved rather than flat. It was Einstein who developed the theory that showed us that space is indeed curved – and that gravity is the all-important force that leads to this curvature. In cosmology, the big questions are what the shape of the universe is and where space came from. The origin of space is generally held to be the Big Bang, 13.8 billion years ago, which created space – which has been expanding rapidly ever since. As yet, we do now know the shape of the Universe – but as we expand our knowledge of the far reaches of the Universe, both in time and in the matter it contains, we will start to fill these gaps in our understanding of space. The next issue is how we measure space – which is now done using the International System of Units (SI) used in most parts of the world. The standard space interval – a standard metre – is defined as the distance travelled by light in a vacuum during a time interval exactly 1/299 792 458 of a second. And then of course there is quantum mechanics – where the ‘space’ deals with physical phenomena at nanoscopic scales. In this branch of physics, scientists are dealing with ‘space’ at atomic and sub-atomic length scales. In this case ‘space’ is described by the particle-like and wave-like behaviour and interactions of energy and matter. A simple word like ‘space’ opens up a world of observation and theory – the true beauty of science.
Bridget Farham Editor – QUEST: Science for South Africa All material is strictly copyright and all rights are reserved. Reproduction without permission is forbidden. Every care is taken in compiling the contents of this publication, but we assume no responsibility for effects arising therefrom. The views expressed in this magazine are not necessarily those of the publisher.
Probing our cosmic past PAPER – and South Africa – at the cutting edge of physical cosmology. Quest explains how PAPER can do this.
The PAPER array in the Karoo under the night sky. Image: SKA
stronomers are looking back at the earliest epoch of star and galaxy formation in our Universe by mapping distant hydrogen gas. PAPER – the Precision Array to Probe the Epoch of Re-ionisation – is a low-frequency radio interferometer that is designed to detect the explosion of the first stars and galaxies around 500 million years after the Big Bang. Before we go any further, let’s examine exactly what this paragraph means. The Universe is now around 13 billion years old. But when the Universe was only 300 000 years old there were no stars or galaxies – only a Universe filled with hydrogen and a small amount of helium. Eventually, stars and galaxies started to form, but the earliest galaxies that we can see using current telescopes are from a time when the Universe was already one billion years old. So how did these stars form and what were the first galaxies like? We can’t yet see these first stars and galaxies, but we may be able to detect the effects that they have on the space around them. The first stars were so massive and hot that they emitted lots of ultraviolet (UV) radiation, and it is this UV radiation that can ionise hydrogen. Importantly, the original neutral hydrogen in the Universe emits a radio signal with a frequency of 1.4 GHz. The PAPER array should be able to detect the hydrogen from the early Universe – before it was ionised – and then study and map it as bubbles of ionised hydrogen formed around the first galaxies. Essentially, radio astronomers will be watching the emission from neutral hydrogen disappear from the data as we get closer to the present day. This happened such a long time ago that the radiation has been stretched – what is called redshifted – as the Universe has expanded and the signal will arrive somewhere between 100 and 200 MHz – close to the FM
Interferometry and seeing radio waves It will help if you can find two articles – one from Quest 8(3) 2012 by Oleg Smirnov and the other from Quest 9(2) 2013 by André Young and David Davidson. In the first article Oleg explains that interferometry is a way to massively improve the spacial resolution of radio telescopes. It is a method by which radio or light waves that are received at two different locations are combined and the resulting interference pattern is measured. Careful measurement of this pattern allows us to achieve an effective resolution that is determined by the distance between two locations. In the second article, André and David explain that radio astronomy is the way that we ‘see’ celestial bodies that produce electromagnetic radiation within the radio frequency or RF band of the electromagnetic spectrum (see below). They explain how antennas transform the incident electromagnetic waves into an electrical signal – current flowing through the terminals attached to the antenna – which are then manipulated, measured and analysed.
dial on a radio. This is a very faint signal, so the radio telescopes that are used to detect this radiation have to be somewhere where there is as little interference as possible – hence the PAPER array as part of the SKA infrastructure in the Karoo – and also in the Australian outback. The epoch of re-ionisation Re-ionisation in Big Bang cosmology is the process that re-ionised the matter in the Universe after what are called ‘the dark ages’ – a period during which the Universe was ‘foggy’ – there is light, but it is not light that we can see through telescopes. The diagram of the history of re-ionisation shows the timeline. This is the second of two major phase transitions of gas in the Universe. At this stage most of the matter in the Universe – called baryonic matter (atoms of any sort) is in 10| 1 2014
The PAPER array showing the link to the correlators. Image: SKA
the form of hydrogen. So re-ionisation usually refers to the re-ionisation of hydrogen gas – in this case PAPER will be mapping the 21 cm emission of neutral hydrogen.
A single dipole antenna. Image: SKA
Three SKA interns work on a PAPER antenna in the Karoo. Image: SKA
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How will PAPER ‘see’ this radiation? PAPER is in partnership with the South African National Research Foundation and has funding provided by the National Science Foundation (NSF). South Africa has been involved in the PAPER experiment since 2010. In the middle of 2013 an additional 52 PAPER antennas were deployed in the Karoo, bringing the total number of antennas in the array to 116. A further 12 were added in November 2013 and the array was fully functional by December 2013. ‘We have exciting times ahead of us. PAPER has started the observing campaign that could lead to measure the Epoch of Re-ionisation’, says Dr Gianni Bernardi, member of the South African PAPER team. ‘Paper started as four dipoles and a laptop; it is now at 128 dipoles and a cluster of computing hardware. There is a go big or go home attitude with this project’, says Dr Griffin Foster-Rhodes, postdoctoral researcher. The PAPER instrument is made up of these 218 dipole antennas, which are connected into an interferometric array. These antennas are sensitive to 100-200 MHz electromagnetic radiation. The new antennas increase the sensitivity of PAPER and effectively quadruple the amount of data produced by the array. The PAPER team are now upgrading the digital back end of the antennas to accommodate this increase in data. The PAPER team have commissioned an impressive 256-input correlator. This is a custom-built array of supercomputers, made up of Reconfigurable Open Architecture Computing Hardware (ROACH) boards and multiple Graphic Processing Units (GPU). They will be among the world’s largest and most powerful radio astronomy correlators.
A diagram showing the process of re-ionising neutral hydrogen. Image: astrobites.org
A schematic timeline of the Universe, showing re-ionisationâ€™s place in cosmic history. Image: Wikimedia Commons
A view of the PAPER array in the Karoo, showing the area that is covered by the dipole antennas. Image: SKA
The PAPER team in the Karoo. Image: SKA
Neutral hydrogen The hydrogen line, 21Â cm line or HI line is the electromagnetic line that is created by a change in the energy state of neutral hydrogen atoms. This wavelength or frequency falls within the microwave spectrum of the electromagnetic spectrum. This is the region that is often observed in radio astronomy because these radio waves can penetrate the large clouds of interstellar cosmic dust that are opaque to visible light. http://en.wikipedia.org/wiki/Electromagnetic_spectrum
This image of the giant radio galaxy, Centaurus A, was generated by PAPER. Image: SKA
PAPER is already producing new science, but at the same time it is part of the design of a next-generation Hydrogen Epoch of Re-ionisation Array (HERA) and the lowfrequency SKA. PAPER is a collaboration between SKA South Africa and a US-based consortium consisting of the National Radio Astronomy Observatory, the University of Virginia, the University of California Berkeley and the University of Pennsylvania. Q
The electromagnetic spectrum. Image: Wikimedia Commons
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An artist’s impression of the Kepler space craft. Image: NASA
EXOPLANETS the search for Earth-like planets There are literally billions of planets within the Milky Way that are potentially Earth-like. Quest investigates the Kepler Space Mission.
n November 2013, astronomers using the Kepler Space Mission data reported that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of sun-like stars and red dwarfs within the Milky Way Galaxy’. This quote from Wikipedia really fires up the imagination – 40 billion Earth-sized planets, all within the habitable zones of stars similar to our own Sun. These planets are called extrasolar planets or exoplanets – any planet outside our own solar system. What are exoplanets? Before we can understand what exoplanets are, we need to know about the Kepler Mission. The Kepler Mission started off as a NASA Discovery mission, specifically to search for planets that are orbiting other stars that have characteristics that are similar to those on Earth. In the past few years, scientists have found nearly 400 stars with orbiting giant planets. The challenge is to find terrestrial planets, which are around half to twice the size of Earth – particularly those in the ‘habitable zone’ of their stars – where liquid water and, possibly, life may exist. Kepler is the first mission that is capable of detecting Earth-size and smaller planets in or near the habitable zone. In 2009, oversight of the Kepler
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project was transferred from NASA’s Discovery Program to the Exoplanet Exploration Program. But the Kepler Mission is not simply about finding out where there are Earth-like planets. The knowledge of the range of planets within the Milky Way will allow us to place our solar system within the continuum of planetary systems in the Galaxy – our place in space. Kepler will do all this by surveying a large sample of stars to find out how many larger and terrestrial planets in or near the habitable zone there are, look at their characteristics such as orbit sizes and shapes and work out the properties of those stars that do have planetary systems. How does Kepler detect exoplanets? Kepler detects planets by ‘seeing’ a tiny reduction in the brightness of stars as planets pass in front of these stars. This is called the transit method of detecting exoplanets. To do this, Kepler will look at one large area of the sky in the constellations Cygnus and Lyra. As the mission continues, the spacecraft will simultaneously measure the brightness of more than 100 000 stars every 30 minutes – looking for the periodic dimming of the star that can be seen when a planet passes in front of its star. These changes in brightness
The image on the left shows a Jupiter transit across an image of our Sun and the image on the right shows an Earth-sized transit. Image: www.kepler.nasa.gov An example of a system based on stellar luminosity for predicting the location of the habitable zone around various types of stars. Planet sizes, star sizes, orbit lengths and habitable zone sizes are not to scale. Image: Wikimedia Commons
The Goldilocks zone In astronomy and astrobiology the circumstellar habitable zone (CHZ) – called the Goldilocks zone – is the region around a star in which planet-sized objects that have enough atmospheric pressure can support liquid water on their surfaces. The boundaries of this zone are calculated using what we know about the requirements of Earth’s biosphere, its position in our solar system and the amount of radiant energy it receives from the Sun. The temperatures on the planet’s surface must be right for water to exist in its liquid form. Liquid water is important because of what we know about the role of water in the origins and support of life as we know it on Earth. The concept of the CHZ was first put forward in 1953 and since then many planets have been discovered in this zone. So far, most of these planets are far more massive than Earth – super-Earths or gas giants – and so are relatively easy to detect. The nearest of these planets may be as close as 12 light-years away. Source: http://en.wikipedia.org/wiki/Circumstellar_habitable_zone
are roughly 1 part in 10 000 and can occur for an hour or for about 12 hours, depending on the planet’s orbit and the type of star. Transits are only seen when a star’s planetary system is nearly perfectly aligned with our line of site. Given that there is no preferred plane of alignment for the orbit of a planet and its host star, Kepler must observe a huge number of stars in order to detect a planet in this way. For a planet in an Earth-size orbit, the chance of the planet being aligned in a way that will allow us to see the transit is less than 1%. The discovery of a planet is confirmed by observing several transits that have the same change in brightness of the star (depth), time to transit the star and the same amount of time between successive transits (period). A single event that looks like a transit must be confirmed by observing repeated transits with the same period and depth. The chance that the orbital plane of a planet is aligned with the observer’s line of sight so that a transit can be seen is equal to the ratio of the diameter of the star to the diameter of the planet’s orbit. Planets that are very close to their host star – and too hot for life – have a probability of alignment of 10%. Planets in the larger orbits – the habitable zone of their star – have a probability of alignment of 1% or less. So the transit method misses 90% of the inner orbit planets and 99% or more of the planets in the habitable zone orbits. This is why the design of Kepler required a very wide field telescope so that it could observe more than 100 000 stars. We can assume statistically that for every planet that Kepler detects, there are 100s more planets out there that cannot be detected because their alignment is not right.
The field view of the constellations of Cygnus, Lyra and Draco. Image: NASA, Carter Roberts
Which part of the sky is Kepler looking at? As we said before, Kepler is looking at just one large area of the sky – in the constellations of Cygnus and Lyra. This region of the sky is in the northern hemisphere. This star field was chosen because Kepler must be able to see the field continuously throughout the mission and the field needs to have plenty of stars that are similar to our Sun. The stars being observed by Kepler are from a few hundred to a few thousand light years away. One light year is about 9.5 trillion kilometers. Kepler is looking along the Orion spiral arm of our galaxy. The distance for which Earth-sized planets can be detected by Kepler is from 600 to 3 000 light years and less than 1% of the stars that Kepler is looking at are closer than 600 light years. Stars that are further than 3 000 light years are too faint for Kepler to detect the transits that are needed to find Earthsized planets. 10| 1 2014
This artist's impression shows Kepler-22b. Image: NASA/Ames/JPL/Caltech
This diagram compares our solar system to Kepler-22, a star system containing the first ‘habitable zone’ planet discovered by NASA's Kepler mission. Image: NASA/Ames/JPL/Caltech
The size of Kepler planet candidates. Image: NASA
Kepler’s search volume in relation to the Milky Way Galaxy. Image: Jon Lomberg, NASA
Earth-like planets In 2011, the Kepler mission confirmed that it had found the first planet orbiting in the habitable zone of its parent star. This planet, called Kepler-22b, was the smallest found at that time which was also in orbit around a star similar to our Sun. Kepler-22b is a planet known to comfortably orbit in the habitable zone of a Sun-like star. It was the first planet that NASA's Kepler mission had confirmed to occupy a star's habitable zone – the region around a star where liquid water, a requirement for life on Earth, could persist. The planet is 2.4 times the size of Earth, making it the smallest yet found to orbit in the middle of the habitable zone of a star like our Sun. Scientists do not yet know if the planet has a predominantly rocky, gaseous or liquid composition. It's possible that this world would have clouds in its atmosphere, as shown in the artist's interpretation. Kepler-22b's star is a bit smaller than our sun, so its habitable zone is slightly closer in. The diagram shows an artist's rendering of the planet comfortably orbiting within the habitable zone, similar to where Earth circles the Sun. Kepler-22b has a yearly orbit of 289 days and is the smallest known planet to orbit in the middle of the habitable zone of a Sun-like star. It's about 2.4 times the size of Earth and 600 8
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light-years away from Earth. More recently, in January 2013, a study was published suggesting that the Milky Way Galaxy contains at least as many planets as it does stars – potentially 100 - 400 billion exoplanets. This study is based on planets orbiting the star Kepler-32 and suggests that planetary systems may be common around stars in our galaxy. The discovery of a further 461 exoplanet candidates was announced on 7 January 2013. In April 2013, NASA announced three new Earth-like exoplanets – Kepler-62e, Kepler-62f and Kepler-69c – in the habitable zones of their respective host stars. However, it appears that Kepler-69c is probably more like Venus than like Earth, and so not habitable. Due to a hardware malfunction, Kepler was disabled and in August 2013, NASA announced the end of the original Kepler mission. However, a new proposal (Kepler ‘Second Light’) has been put forward, which will see the Kepler satellite continue to search the skies for exoplanets in a new way. The mission concept is currently under review. If continued, the search for Earth-like planets will go on – and who knows what the future will bring. Q Additional material for this article was provided by Dr Caroline Zunkel. She received a BSc in Physics and Chemistry and a BSc (Honours) in Physics from the University of Natal (Pietermaritzburg). In 2004 she enrolled in the National Astrophysics and Space Science Program (NASSP) and completed an MSc (Astrophysics) in 2005 at the University of Cape Town. She received a PhD (Astrophysics) from Oxford University (UK) in 2008 and a joint postdoctoral fellowship between the Astrophysics Department at Princeton University (USA) and the School of Mathematical Sciences at the University of KwaZulu-Natal. She is now a lecturer in the School of Chemistry and Physics at UKZN.
SCIENCE IS THE GLUE THAT HOLDS EVERYTHING TOGETHER
verywhere you look, you’ll see science hard at work, making society a better place in which to live. From the food you eat to the clothes you wear; from the battery in your cell phone to the mp3 files in your music player, it’s all about the science. South Africa needs more scientists if it is to compete on a global scale; people who are enthusiastic about finding solutions to today’s challenges and pushing the frontiers of the future. If you want to make a real difference, consider a career in science.
f u t u r e.
w w w. s a a s t a . a c . z a
SANSA utilises space technology to stimulate socio-economic development
he establishment of the South African National Space Agency (SANSA) in 2010 was a giant leap for South Africa’s undertakings in space science and technology and heralded a new era in the exploitation of space technology in service of humanity. In its third year of operation, the agency has been instrumental in moving South Africa into the global space arena as a serious space contender. SANSA offers state-of-
the-art products, services and infrastructure that impact on the local and global economy, knowledge economy as well as the lives of all our citizens. As an entity of the Department of Science and Technology, SANSA is tasked with co-ordinating the development of a national space programme for South Africa in collaboration with various local and international stakeholders.
SANSA’s SuperDARN radar array located at the South African research base SANAE IV in Antarctica. Image: Rob Coetzee (S52)
Understanding space plasma Three projects come together to gain a deeper understanding of the world of space plasma.
digital upgrade to the South African super dual auroral radar network (SuperDARN) radar in Antarctica, the construction of a high-frequency direction finding (HF/DF) interferometer array, and the tricky business of uncoiling a wire in space will all come together to give SANSA extended capabilities in space weather monitoring and space plasma studies.
The team who installed and helped develop the new SuperDARN radar at the Antarctic research base SANAE IV. They each performed the role of SANAE IV Radar Engineer over the last five years. Left to right: Francois Olivier (S53), Philip Mey (S52), Jonathan Ward (S51), Ruan Nel (S50) and Roger van Schie (S49). Image: Brett Anderson (Dartmouth College/NASA)
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Part 1: Icy challenges for SuperDARN project The SA Agulhas II’s December voyage to Antarctica saw the polar research and logistics vessel encounter tough conditions just before Christmas. Strong currents and thick sea-ice prevented the ship from reaching the ice-shelf, which caused a two-week delay. When Gert Lamprecht, SANSA’s Research Support Unit Manager, arrived at the South African Antarctic base,
❚❚❚❙❙❙❘❘❘ SANSA News
SANAE IV, he and his team were told they would have three weeks less time to install SANSA’s new high-frequency digital radar system. The radar is part of an international network of 33 radars distributed over the northern and southern polar regions, called SuperDARN. The new digital radar is going to replace the existing 17-year-old analogue radar, which was due to be decommissioned in 2012, and will provide a more versatile, reliable and state-of-the-art research platform for scientists to study the ionosphere and other space weather-related phenomena. Antarctica is the optimal place for space weather research instrumentation because the Earth’s magnetic field lines converge at the poles and act as a funnel for space plasma to travel into the Earth’s atmosphere. A single pair of radars in the network can measure the position and movement of ionospheric plasma in an area of approximately 4 million square kilometres. Two engineers from Lamprecht’s team will stay behind on the ice for 14 months to monitor and maintain the suite of space-monitoring instruments that SANSA operates from the base. Despite the delay and the hostile Antarctic environment, the project is still on schedule and the team’s enthusiasm has not dampened. The SuperDARN radar is made up of two parts the antenna array and the recently-upgraded digital radar rack (the brain of the radar). Part 2: Uncoiling an antenna in space While the new SuperDARN radar is being installed in Antarctica, back on the home front, SANSA is managing an experimental aspect of South Africa’s first CubeSAT mission. The engineering team had to figure out how to broadcast a long-wave radio signal using an antenna on a satellite that is only 10 cm3 and can fit in the palm of your hand. The satellite, called TshepisoSAT, had to have an antenna of 10.5 m attached to it. That’s a big feat for a small satellite. So, Prof. Robert van Zyl and his team from the Cape Peninsula University of Technology (CPUT) devised a rolled-up antenna, coiled like a fishing rod reel. Now that TshepisoSAT has been launched, the 0.01 mm thick wire must be slowly uncoiled into a straight antenna. With a small tip mass placed at the wire’s end, the satellite will be put into a spin, using the Earth’s magnetic field and two small electromagnets fitted to the CubeSAT. This process should slowly uncoil the wire, which is similar to a piano wire in rigidity. If it bunches up or bends too much,
The HF beacon on board TshepisoSAT. The 10.5 m antenna is coiled in the reel like casing. Image: CPUT
The 10 cm cubic satellite known as TshepisoSAT, meaning ‘promise’ in Sotho. Image: CPUT
it will fail. During the daily communication opportunities with the satellite, which are about eight minutes, approximately 2-10 cm of antenna wire will be uncoiled per day. If all goes well, it should be straightened out over a period of several weeks. TshepisoSAT is the first nano-satellite to be constructed in South Africa. Funded by the Department of Science 10| 1 2014
and Technology, the satellite was designed and built by postgraduate students at the French South African Institute of Technology (F’SATI) at CPUT, in collaboration with SANSA. This approach offers students a unique learning experience and prepares them very well to participate in the South African space industry. The satellite is currently healthy and with most tests completed, it is ready to begin the experiment. When extended, the antenna will transmit a simple radio signal that can be received by the Hermanus HF/DF array and the SuperDARN radar in Antarctica, as well as the rest of the SuperDARN network. This will ensure that there are comparable data and will enable the team to determine what effect the plasma in space is having on the travelling radio wave as it propagates through it. Once the effects of the plasma are known TshepisoSAT can act as an HF beacon, and since its location in space is accurately known, it can be used to calibrate the SuperDARN radar. Part 3: HF/DF interferometer array construction Electric plasma in space has always affected radio frequencies transmitted to earth from man-made satellites
– in the same way that glass diffracts rays of light through windows. SANSA scientists aim to better understand just how plasma diffracts radio waves. This experiment brings together the SuperDARN radar at SANAE IV, the special coiled-up antenna mounted to TshepisoSAT and a HF/DF, under construction at the Hermanus facility. The project started out small – three separate antennas laid out in the shape of an ‘L’ are being constructed on an area of 10.5 m. Each antenna consists of two square loops, 1 m in diameter. The mini-array should take six weeks to complete and ultimately there will be seven antennas, the last four of which will be built when the test signals from TshepisoSAT’s special antenna are confirmed as successful. When the CubeSAT’s transmissions from a known position in space are received by either SANAE IV or the Hermanus HF/ DF array, the difference between the measured and the true incoming angles of the radio wave at either antenna locations should supply the team with enough comparable data to determine just how the signal has been refracted by the plasma in space. Experience gained from this project will be used to calibrate SANSA’s SuperDARN radar and the resulting data will be invaluable to gain a better understanding of how radio signals propagate through space.
What’s hot? SANSA’s pick of the month for your smart phone or tablet. Space Junk Space Junk is a simple but affordable application. It allows users to track satellites, check the location of planets and stars, and follow the International Space Station and Hubble telescope as they pass overhead. Constellations and solar system computations can also be displayed, and anything the user finds can be tagged and shared on Facebook. Satellite paths can be displayed, and spacecraft can be arranged by brightness or popularity, or filtered to only show amateur radio satellites. A Sky View allows for looking
up like in a planetarium, while Earth View allows for the opposite. A marker shows your location on Earth. Find it here: Space Junk is available on the Android Play store as Space Junk Lite (R10.92), or in the Apple store, where it’s known as Space Junk Amateur (R11.17). Also try these websites for your space-news fix: www.nasa.gov/multimedia/nasatv/ http://www.esa.int/esatv/Television https://www.aiaa.org http://spaceflightnow.com/ http://www.space.com/news/
Tracking goes digital New satellite tracking web application.
new web application has recently been developed and is making satellite tracking more accessible. The app allows radio amateurs, hobbyists and other scientists with an interest in TshepisoSAT (formerly ZA-CUBE-1), SumbandilaSAT, SUNSAT and the International Space Station to track their path as they orbit earth. The app is elegantly simple. Once a user selects a satellite, a world map highlights the satellite’s footprint. Users can then enter their own location to see exactly when the satellite will pass over their specific area. The default co-ordinates are set to the SANSA facility in Hermanus, but any custom co-ordinates can be entered, and the app is open to anyone with web access. According to SANSA Researcher Dr Ben Opperman, the
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app will be invaluable to radio amateurs, for example, who have often played a role in assisting SANSA in collecting data from satellites. He also believes that being taught to code is essential for scientists: 'One simply cannot conduct effective research if you cannot write your own computer programs'. The satellite tracking app was designed on open source Python software with custom Matlab code written for detailed offline simulations and analyses. Students and engineers at the Cape Peninsula University of Technology currently use the system, but the team is hoping it will enable and attract a whole new audience of space enthusiasts. The web app is available at http://webapps.sansa.org.za/ zaspace
❚❚❚❙❙❙❘❘❘ SANSA News
Above: Spot 6 multispectral image acquired on 1 May 2013. The image shows agricultural fields in the Free State. Image: SANSA Right: SPOT 6 image of Cape Town. Image: SANSA
South Africa is ready for SPOT 6 reception
ANSA will begin receiving satellite imagery from the new SPOT 6 high-resolution Earth observation satellite this year. This-award winning satellite is an improvement on its predecessor, SPOT 5, which has provided high-resolution images for successful use across numerous Government departments and public or private institutions in South Africa. Some applications of SPOT 6 include use by Government to address national priorities such as housing and infrastructure planning and implementation, monitoring and evaluation of our natural resources such as water,
monitoring and management of natural disasters such as floods or fires and for uses in agriculture. A SANSA workshop in November 2013 showcased applications from SPOT 6 in mining, water management and urban planning. During January, a final test was conducted on SPOT 6’s last contract procedural requirement before being approved by the European Space Agency to start its Earth observation mission. SANSA has signed a contract with Astrium to receive and distribute SPOT 6 data, which will be available from April 2014. Q 10| 1 2014
CLOUDS – an enigma in the climate puzzle Mike Lucas explains the fluffy white (and black) things in the sky
A large, black stratus rain cloud. Image: freebigpictures.com
aze upwards outdoors and the chances are you will see fluffy white clouds floating gently across the sky, or clouds that loom menacingly and grey, heavy with the promise of rainfall. Pictures of Earth from space show that 60 - 70% of our ‘blue planet’ is covered by clouds that swirl in great vortices (whirlpools), carried by the wind at altitudes typically of 500 - 1 000 m or so, but often much higher. What are clouds? So what are clouds made of? At low altitudes, clouds consist of small droplets of water of varying sizes, but at high altitudes of several kilometers, clouds consist of tiny ice crystals in the freezing thin air. Clouds form when water vapour from the Earth’s surface rises into the atmosphere, cooling as it does so, until it condenses into water droplets. If the air temperature is low
Our blue planet. Image: www.spacetelescope.org
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enough, ice crystals form. Cloud cover over the oceans is on average greater than over land, because the oceans are a much better source of moisture than the land. Clouds over the ocean are dominated by warm marine boundary layer clouds – so-called because they form at the boundary between the ocean and the lower atmosphere. These clouds lie between 400 and 600 m above the ocean surface, particularly near coasts above cold ocean currents, such as off the west coasts of North and South America, and Africa. Nearly half of all marine boundary clouds are horizontally orientated layer clouds, such as the thick, grey and uniform blanket-like stratus clouds that dump rain on the Cape in winter. Other common types of cloud that are found over both oceans and land are the more vertically orientated cumulus clouds that form in updrafts, or ‘thermals’, caused when warm air rises. These are the same thermals that vultures or eagles soar on, perhaps alongside an intrepid hang-glider pilot. Cumulus clouds are the white fluffy cotton-wool like clouds that float across blue skies on sunny days. The tall, anvil-shaped thunderclouds of the highveld on hot, muggy summer afternoons are cumulonimbus clouds, which also form as hot air rises from the sun-baked landscape. Thin high-altitude and wispy ‘horse's-tail’ cirrus clouds are composed of ice crystals and develop in the freezing upper atmosphere. Clouds and rainfall Farmers look to the clouds to bring rain, but how does this happen? When relatively warm air rises and cools higher in the atmosphere in low-pressure (LP) systems, water vapour in the rising air condenses into rain droplets, which fall as rain. Conversely, when cold air sinks and warms near the
A large cumulonimbus cloud showing the classic anvil shape. Image: Wikimedia Commons
A sky with many different types of cirrus cloud. Image: Wikimedia Commons Left: Small cumulus clouds. Image: Wikimedia Commons
The interplay between water vapour and clouds
ground in high-pressure (HP) systems, this causes dry conditions. Mountains and tropical rain forests create their own micro-climates and weather patterns. When low-level clouds that are carried by the wind are forced to rise over high mountains, the air cools and cloud droplets condense into rain droplets and rain falls on the windward side of the mountains. As the now drier airflow later sinks and warms on the other ‘lee’ side of the mountains, the rain stops. Any remaining moisture returns to water vapour and the lee side of the mountains experience dry or even desert conditions in the ‘rain shadow’. Tropical rain forests like the Amazon jungle cause their own rainfall. As the trees suck up moisture from the ground, much of this is lost to the atmosphere as ‘transpiration’ through their leaves. In fact there is sufficient moisture lost in this way to form clouds as the warm moist air rises, which in turn condenses into rainfall. Clouds and Earth’s heat balance Quite apart from their role in Earth’s hydrological (water) cycle, clouds play an extremely important role in maintaining Earth’s temperature. Our brightly burning sun radiates unimaginably large amounts of energy into space, warming our Earth sufficiently to make it a habitable planet. By contrast, Venus, our neighbouring planet closer to the sun, is far too hot, while Mars, our more distant neighbour from the sun, is far too cold. So Earth is neither too close, nor too distant from our sun, which is nearly 93 million miles away. But this is not the whole story. Without the naturally warming effect of our atmosphere, Earth’s temperature would be about 33°C cooler than it is and would have a global average of about -18°C, rather than the current +15°C. The heat-trapping properties of the atmosphere are due to the so-called ‘greenhouse gases’, such
Molecule-for-molecule, water vapour (WV) is a more important greenhouse gas than CO2, but it is not counted as a human-caused or ‘anthropogenic’ greenhouse gas. Human actions have directly changed CO2 concentrations in the atmosphere, but have only indirectly changed the amount of atmospheric WV by causing the Earth and atmosphere to warm. This in turn alters cloud cover, with either warming or cooling effects, depending on the type and altitude of the clouds. The climate change debate rages around CO2 as the major culprit responsible for global warming, but in fact WV is the most powerful of the greenhouse gases. Just like CO2, WV also absorbs and re-emits infrared radiation (IR) in exactly the same way, which has a warming effect. The greenhouse effect of WV is greater than that of CO2 partly because of how it regulates IR, and partly because WV can reach concentrations of up to 3% of Earth’s atmosphere relative to CO2 concentrations of just 0.03% by volume. But the problem with assessing the greenhouse effect of WV is that its concentration in the atmosphere is extremely variable and relatively short-lived compared to CO2, so CO2 is considered the most important of the greenhouse gases because of its longevity and its direct origin from fossil fuel burning. Where then do WV and clouds fit into the climate change debate? The importance of WV and clouds is recognised in climate change models as a potentially warming and cooling feedback mechanism, respectively. The argument runs like this. With CO2-driven global warming, there is more evaporation of WV from the Earth’s surface, particularly in warm tropical and sub-tropical regions, especially from the oceans. Water vapour added to the atmosphere this way should result in a ‘positive feedback’ loop and should, theoretically at least, result in further warming, since it is after all a greenhouse gas. Conversely, of course, any global cooling would reduce the amount of WV in the atmosphere, resulting in a negative or cooling feedback. So is there any evidence for one or the other effects? Herein lies the problem – we don’t really know, because there is no convincing evidence from past instrument records to support either a positive or negative feedback response. The major complicating factor with WV is that the greenhouse heating that produced WV in the first place results in moist air that rises and cools, condensing into clouds that later produce rainfall. Over the ocean at least, these thick low-level marine boundary layer stratus clouds have a strong albedo effect (see p. 16). It is certainly conceivable, therefore, that the interplay between the greenhouse effect of WV and the albedo of resulting stratus clouds just about balance out, which is why the supposed warming effect of WV is not yet measurable, despite being predicted in climate change simulation models. Courtesy of Bob Scholes, CSIR.
as water vapour (H2O), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These are all minor constituents of the atmosphere – less than 1% by volume – but they play a vital role. The Earth’s overall temperature remains more or less in balance over long periods of time because the heat that is absorbed by the Earth’s surface is more or less in balance 10| 1 2014
An aerial view of the Amazon rain forest. Image: Wikimedia Commons
with the heat that is re-radiated (reflected) back into space. It is here that clouds play an essential but enigmatic role in controlling Earth’s heat balance. When all the relative effects of clouds, aerosols, greenhouse gases and Earth’s albedo are accounted for, a radiation balance for Earth can be created. The Earth’s albedo is its reflection coefficient. It is the ratio of reflected radiation from the surface of the Earth to the incident radiation upon the Earth’s surface.
The amount of radiation arriving at Earth’s outer atmosphere is given an arbitrary value of 100. However, as this radiation passes through the atmosphere towards Earth, about 20% of it is absorbed by the atmosphere and warms it, while about 23% is scattered back into space by clouds. The remaining 57% finally reaches Earth’s surface, which either absorbs this heat, or re-emits it as long-wave infra-red radiation back towards space. At Earth’s surface, the re-radiation or albedo effect ranges from 3% - 10% for dark oceans and land, but 90% for fresh snow and ice. The globally averaged albedo effect is 9%. Clouds and greenhouse gases, however, exert the strongest regulatory control on Earth’s radiation balance. Clouds and minute particles in the atmosphere called aerosols play a major role in Earth’s radiation balance. The climatic effect of aerosols is usually rather small and transient, although sulfate aerosols produced by the volcanic eruption of Mount Pinatubo (1991) cooled Earth by nearly 0.5°C for 2 - 3 years. Clouds, on the other hand, have a very large and longlasting effect on climate because their albedo effect is substantial, reflecting 20 - 30% of incoming radiation back into space. Clouds are so important that even a small increase in overall cloud albedo could offset global warming due to man-made greenhouse effects. But clouds are mysterious because of their complex and contrary effects. Depending on the type, thickness and altitude of clouds, and whether it is day or night, clouds can either cool or warm Earth’s surface. Assessing these effects right now is difficult enough, but climate change itself will probably alter Earth’s cloud cover and type, so predicting their effect on Earth’s future radiation balance is extremely difficult. At its simplest, cloudy days are cool while sunny, cloudfree days are hot, as we all know. On the other hand, cloudy nights are warm, while starry cloud-free nights in hot deserts, for example, can be numbingly cold. The 16
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A rain shaft at the base of a thunder cloud. Image: Wikimedia Commons
explanation is simple enough. On cloudy days, the albedo effect of clouds cools Earth by reflecting incoming radiation back into space, while at night, they behave like a duvet and prevent heat loss into space. Matters are substantially more complicated than this, however. Whether clouds exert an albedo effect or behave like a greenhouse gas depends on their type, height, thickness and composition. Low thick cumulus and stratus clouds have an overall cooling effect because their albedo dominates their greenhouse effect. By contrast, high thin cirrus clouds tend to warm Earth’s surface because their greenhouse effect exceeds their albedo effect. The same is true for contrails produced by high-flying jets. To understand why clouds can have both albedo and greenhouse effects, the way in which clouds re-radiate heat needs to be understood. Clouds not only reflect incoming short-wave radiation back into space, but like greenhouse gases, they absorb and re-emit long-wave infra-red radiation that is reflected from Earth’s surface. The key point is that they re-radiate the absorbed long-wave infra-red radiation in all directions, some being lost to space, and some warming the Earth below. Whether that process cools or warms Earth depends on the height and the temperature at which infra-red radiation is re-emitted. If infra-red radiation is re-emitted at cold high altitudes, it enhances the greenhouse effect, but if infra-red radiation is re-emitted at low warm altitudes, the greenhouse effect is weak. Elongated ice crystals of high cirrus clouds and jet contrails are mostly transparent to incoming short-wave solar radiation, so their albedo effect is low. In addition, cirrus clouds absorb and re-emit infra-red radiation from the Earth’s surface at a high, cold altitude. Combined with their low albedo, cirrus clouds therefore make a large contribution to the atmospheric greenhouse effect. By contrast, low-lying stratus clouds have a strong albedo effect, and although they too absorb and re-radiate infrared, they do so at warm low altitudes – so their greenhouse effect is weak and insufficient to counter their strongly cooling albedo effect. These two cloud types, therefore, work in a contrary fashion. Low stratus clouds cool the Earth, while high cirrus clouds warm the Earth. The relative proportions of these two cloud types, therefore, have a big impact on climate. As it stands today, the two effects just about cancel each other out, with clouds on average having a slightly greater albedo and therefore an overall cooling – or negative feedback – effect. The crucial question, however,
A photograph of the Earth over South America taken from the Space Shuttle (Mission STS 43) on 8 August 1991, showing the double layer of Pinatubo aerosol cloud (dark streaks) above high cumulonimbus tops. Image: Wikimedia Commons
The eruption of Mount Pinatubo on 12 June 1991. Image: Wikimedia Commons
is how will global warming affect both cloud cover and type, since this will have a considerable impact on Earth’s radiation balance? The answer is a very uncertain one. As oceans warm, you would rightly expect increased evaporation to increase the amount of atmospheric water vapour, which condenses to form clouds. This ought to add to albedo and therefore cool Earth, and so it would do if low-level stratus clouds were produced. However, some early climate change modelling experiments produced totally unexpected answers – the models produced a warming effect; a positive rather than a negative feedback. The reason was that increased temperatures produced high-altitude moisture convection, resulting in cirrus cloud formation with low albedo and a strong greenhouse effect. But it is unlikely that only high-altitude cirrus clouds will form, and more likely that low-altitude stratus clouds will also form. New coupled land-ocean-atmosphere general circulation models (GCMs) are beginning to link cloud formation and type with the degree of water vapour saturation, cloud condensation nuclei and aerosols, including important, but very poorly understood, physical interactions at the scale of water droplets and aerosol particles. Early models did not include these interactions, which accounts for the many past errors and uncertainties. The newest models are improving, but they are exceptionally complex and require years of supercomputing time to produce results. So for the moment at least, clouds remain enigmatic and perhaps best summed up in the words of the 1980s singer and song-writer, Joni Mitchell: ‘I’ve looked at clouds from both sides now From up and down, and still somehow It’s cloud’s illusions I recall I really don’t know clouds at all.’ Q 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.
A spectacular thunderstorm underway. Image: Wikimedia Commons
Thunderclouds and lightning The start of a thunder and lightning storm is characterised by the formation of tall, anvil-shaped cumulonimbus thunderclouds. Thunderstorm clouds result from rapidly rising warm, moist air, driven by the heat of the sunbaked earth. As the warm, moist air rises, it cools, condenses, and forms anvil-shaped cumulonimbus clouds that can reach heights of over 20 km – as high as passenger jets fly. As the rising air reaches its condensation (dew) point, water droplets and ice form and begin falling through the clouds towards Earth’s surface. As the droplets fall, they collide with other droplets and become larger, creating a downdraft of cold air and moisture that spreads out at the Earth’s surface, causing the strong winds commonly associated with thunderstorms. Thunderstorms can result in many severe weather phenomena, including high winds, large hailstones, and flash flooding caused by heavy rainfall. The lightning often associated with thunderstorms is an electrical discharge or bright lightning bolt emanating from the clouds. Lightning occurs when an electrical charge is built up within a cloud, due to static electricity generated by super-cooled water droplets colliding with ice crystals. When a large enough charge is built up, a lightning discharge will occur. The temperature of a lightning bolt can be five times hotter than the surface of the sun. Although the lightning is extremely hot, the duration is short and 90% of strike victims survive. Contrary to popular opinion that lightning does not strike twice in the same place, some people have been struck by lightning more than once, and tall buildings and towers can be struck several times during the same storm. This occurs because lightning travels the shortest distance it can between its origin in the clouds and the ground. Consequently, this is the reason why it’s a bad idea to stand under a tree during a lightning storm. If caught out in a lightning storm, find the lowest ground you can and lie down flat, or preferably, find a building for shelter, but stay away from walls and windows. The loud thunderclap heard with lightning is due to the super-heated air around the lightning bolt expanding at the speed of sound. Because sound travels much more slowly than light, the flash is seen before the bang, although both occur at the same moment. The two most common types of lightning are firstly ‘sheet lightning’, where the lightning jumps from cloud to cloud and does not shoot down to the ground, and secondly so-called ‘forked lightning’, which strikes the ground.
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Increased droughts, high temperatures – all the effects of climate change. Image: motherearthnews.com
We are warming the planet – key findings from the United Nations climate science panel (IPCC).
This is indeed the Age of the Anthropocene
Satellite image of ship tracks – clouds created by the exhaust of ship smokestacks. Image: NASA/Earth Observatory
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ublished on 23 September 2013, Working Group 1’s contribution to the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (WGI AR5) provides a comprehensive assessment of the physical science basis of climate change. The report has 14 chapters, a technical summary and a summary for policymakers. The last comprehensive assessment, the Fourth Assessment Report, was published in 2007. Look out for three more reports to be published in 2014: n Impacts, Adaptation and Vulnerability – 25-29 March 2014 n Mitigation of Climate Change – 7-9 April 2014 n Climate Change 2014: Synthesis Report – 27-31 October 2014. Here are a few of the headline statements from Working Group 1’s Summary for Policymakers: n Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. n Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. n The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two
❚❚❚❙❙❙❘❘❘ Climate change
Left: Clouds across the planet. Image: fco.gov.uk
Below: Melting Arctic ice means that polar bears are having to swim for longer periods. Image: Dan Crosbie
millennia (high confidence). Over the period 1901 - 2010, global mean sea level rose by 0.19 m. n The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased to levels unprecedented in at least the last 800 000 years. Carbon dioxide concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification. n Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system. n It is extremely likely that human influence has been the dominant cause of the observed warming since the mid20th century. n Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. n Changes in the global water cycle in response to the warming over the 21st century will not be uniform. The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase, although there may be regional exceptions. n The global ocean will continue to warm during the 21st century. n Global glacier volume will further decrease. n Global mean sea level will continue to rise during the 21st century. n Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. Source: IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group 1 to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [TF Stocker, D Qin, G-K Plattner, M Tignor, SK Allen, J Boschung, A Nauels, Y Xia, V. Bex and PM Midgley (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
(Source: IPCC Working Group 1 Fact Sheet)
Who or what is the IPCC? The Intergovernmental Panel on Climate Change was set up in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). The aim was to prepare assessments, based on available scientific information, on all aspects of climate change and its impacts. In 2007 the IPCC and former US vice-president Al Gore were awarded the Nobel Peace Prize ‘for their efforts to build up and disseminate greater knowledge about manmade climate change, and to lay the foundations for the measures that are needed to counteract such change’. 10| 1 2014
The warming pause – the role of the Pacific In the past 13 years there has been an apparent slowing in the warming of the Earth’s surface. A recent article in Nature Climate Change goes some way towards explaining this.
In 2007-2008 the Gallup Poll surveyed individuals from 128 countries in the first comprehensive study of global opinions on climate change. The map shows the proportion who reported knowing 'something' or 'a great deal' about global warming. Darker areas indicate a greater proportion of individuals aware, yellow indicate no data. In a follow-up survey in 2011, results showed that awareness in sub-Saharan Africa is still among the lowest in the world. (Source: http://www.gallup.com/poll/147203/Fewer-Americans-Europeans-View-GlobalWarming-Threat.aspx#1) Image: Arthur Gunn, http://gunn.co.za/map
This is a schematic of the trends in temperature and ocean-atmosphere circulation in the Pacific over the past two decades. The accelerated atmospheric circulation in the Pacific is indicated by the dashed arrows; including the Walker cell (black dashed) and the Hadley cell (red dashed; Northern Hemisphere only). Anomalously high SLP in the North Pacific is indicated by the symbol ‘H’. Image: Nature Climate Change
Researchers have found that heat stored in the western Pacific Ocean caused by unusually strong equitorial trade winds appears to be the main factor responsible for this pause. These trade winds have, over the past decade, dramatically strenghthened and become faster, which has increased the circulation of the Pacific Ocean and caused more heat to be taken out of the atmosphere and transferred to the subsurface ocean – at the same time bringing cooler waters to the surface. ‘Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures, but the mechanism behind the hiatus remained unclear’ said Professor Matthew England, lead author of the study, and a Chief Investigator at the ARC Centre of Excellence for Climate System Science. ‘But the heat uptake is by no means permanent: when the trade wind strength returns to normal – as it inevitably will – our research suggests heat will quickly accumulate in the atmosphere. So global temperatures look set to rise rapidly out of the hiatus, returning to the levels projected within as little as a decade.’ The strengthening of the Pacific trade winds began during the 1990s and continues today. Previously, no climate models have incorporated a trade wind strengthening of the magnitude observed, and these models failed to capture the hiatus in warming. Once the trade winds were added by the researchers, the global average temperatures very closely resembled the observations during the hiatus. ‘The winds lead to extra ocean heat uptake, which stalled warming of the atmosphere. Accounting for this wind intensification in model projections produces a hiatus in global warming that is in striking agreement with observations,’ Prof. England said. ‘Unfortunately, however, when the hiatus ends, global warming looks set to be rapid.’ The impact of the trade winds on global average temperatures is caused by the winds forcing heat to accumulate below the surface of the Western Pacific Ocean. ‘This pumping of heat into the ocean is not very deep, however, and once the winds abate, heat is returned rapidly to the atmosphere,’ England explains. ‘Climate scientists have long understood that global average temperatures don’t rise in a continual upward trajectory, instead warming in a series of abrupt steps in between periods with more-or-less steady temperatures. Our work helps explain how this occurs,’ said Prof. England. ‘We should be very clear: the current hiatus offers no comfort – we are just seeing another pause in warming before the next inevitable rise in global temperatures.’ Source: sciencedaily.com
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What do South Africans know about climate change? One of the few studies to look at public understanding of climate change in Africa, the BBC World Service Trust report ‘South Africa Talks Climate’ (2010), found that while public awareness of global climate change is high, the science is often not well understood. The situation is aggravated by the fact that most African languages do not have the terminology for concepts like climate change or global warming. Here are some key findings from the study: Most South Africans are aware of global climate change, but their understanding of the science is patchy and they tend to use ‘climate change’, ‘global warming’ and ‘ozone depletion’ interchangeably. The term climate change often triggers associations with some of the global impacts of climate change, such as melting ice caps, rising sea levels, hurricanes and the possible inundation of low-lying countries. Many South Africans do not see climate change as having any special relevance to South Africa or the rest of the African continent. Many use climate change as an umbrella term to refer to the destruction occurring in their natural surroundings, with changes in the weather and seasons forming part of the broader environmental changes people have observed over the course of their lifetimes. Most South Africans tend to view climate change as a ‘green’ issue that only the wealthy can afford to worry about. Despite recognising SA’s contribution to climate change, citizens express reluctance to moderate their lifestyles to reduce carbon emissions, especially as they see little government or private sector leadership on the issue. Many tend to view the destruction of the environment as an inevitable consequence of the country’s development. Many see it as a remote threat and are yet to realise the dramatic impact it could have on their livelihoods in the future, say opinion leaders. The media and schools are people’s main sources of information on climate change. Yet the media struggles to engage audiences with the issue. Many draw on existing knowledge and beliefs to explain the effects of climate change. For example, many incorrectly believe that smoke from cars and factories damages the ozone layer, making it hotter. Some also see changes in the weather as the will of God, a view particularly prevalent among rural populations. Q
Leading minds in engineering
University of Pretoria’s students support the MeerKAT/SKA initiative
A pioneer in microelectronics research The Carl and Emily Fuchs Institute for Microelectronics (CEFIM) in the University of Pretoria’s Department of Electrical, Electronic and Computer (EEC) Engineering has pioneered microelectronics research (both at electron device level and at circuits/systems level) in South Africa over the past 30 years. It is the home of the Electronics and Microelectronics Research Group, where radio frequency (RF) and mm-Wave integrated circuit (IC) design has emerged prominently as a research focus area over the past 10 years.
SKA scholarships A project team from the University’s Department of EEC Engineering is among a number of young scientists and engineers who are involved in research relating to technologies and systems for the MeerKAT telescope, which forms part of the Square Kilometre Array (SKA) Project. Seven undergraduate and postgraduate students are supported through SKA scholarships. A PhD project seeks to integrate a differential low-noise ampliﬁer, using a SiGe technology node, which is aimed at delivering for sensitive SKA receivers. These projects of the Electronics and Microelectronics Research Group are under the leadership of Prof Saurabh Sinha, Director of CEFIM.
Because the telescope that is being developed as part of this project will be a radio telescope, making pictures from radio waves instead of light waves, research conducted in the University’s Department of EEC Engineering will be able to make an important research contribution to this world-class project.
Providing a cost-effective solution Due to the number of front-end receiver arrays anticipated for the SKA Project, the research team aims to develop an IC-based solution, which will be cost-effective. It is envisaged that the SKA Project will require tens of thousands of focal-plane arrays, where the total number of front-end receiver chipsets could range from hundreds to thousands. This calls for an integrated solution, which will reduce the cost of each receiver array. To validate the research ﬁndings, CEFIM is also equipped with on-wafer measurement capabilities, supported by vector network analysis capabilities up to 110 GHz. The research team therefore aims to address a number of innovative concepts relating to IC receivers in the nominal mid-band SKA RF range, such as ultra-low-noise ampliﬁer development, variable gain control, improved I/Q phase and amplitude mismatch, instrumentation or mixed-signal IC design and the identiﬁcation of model parameters inﬂuencing circuit performance.
Leading minds in engineering Universiteit van Pretoria • University of Pretoria • Yunibesithi ya Pretoria Privaatsak • Private Bag • Mokotla wa Posa X 20 • Hatﬁeld • 0028 Suid-Afrika • South Africa • Afrika Borwa Tel: +27 12 420 2164/3637 • Faks • Fax • Fekse: +27 12 362 5000
9| 3 2013
Departement Elektriese, Elektroniese en Rekenaar-Ingenieurswese Department of Electrical, Electronic and Computer Engineering Kgoro ya Boentšenere bja Mohlagase, Elektroniki le Khomphutha www.ee.up.ac.za
How to make your car faster: unichip and performance exhaust Androniki Pouris tells us how to improve a car’s performance without paying a fortune.
A turbocharger. Image: http://www.australianturbo.com.au/
A supercharger. Image: http://rricketts.com/wp-content/uploads/2012/02/supercharger.jpg
hen people want to buy a new car they make their choices using a number of criteria – implicitly or explicitly. How the vehicle looks, its safety (e.g. air bags), comfort (e.g. air conditioning), reliability and of course fuel economy. Similarly, some people look for cars that have turbos, superchargers, high break horse power or high kilowatts in the car. In simple terms, how fast the car can go from point A to point B, or how fast the car can pull away from a standing start. Many younger people now buy vehicles and then modify them – to make them look better or to drive faster. The challenge is that while people would like to have a fast car, they don’t really understand engines well or how their car works. Modifying a car without knowing what you are doing may cause damage rather than make the car faster – and of course you may spend more money than necessary. This article is based on my own and others' experiences of modifying a car. But before I describe my findings, just a little information on turbochargers, superchargers and other devices that everyone wants in their cars to make their cars faster. General background Superchargers and turbochargers are devices that are attached to the engine. They force air into the cylinders, so creating a pressure that is greater than the atmospheric pressure in order to increase engine output.
What is a turbocharger?
The turbocharger is a device which uses the exhaust gas as energy to rotate the turbine wheel at high speeds. There is a compressor wheel on the same shaft as the turbine wheel which compresses air into the cylinders when it rotates. This increases the engine output. What is a supercharger?
A unichip. Image: http://www.unichip.com/Images/Products/Unichip478.jpg with DASTEK permission
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A supercharger is a device that compresses air and so increases the density or pressure of the air that is supplied to the internal combustion
engine. This gives each cycle of the engine more oxygen, letting it burn more fuel and do more work, therefore increasing power. What is a unichip?
A unichip is an electronic engine enhancement product. The unichip is also called a piggy-back computer. It is connected with the vehicle’s existing engine control unit (ECU) and greatly enhances the capabilities and functions of the original computer. It essentially turns the original computer into a supercomputer. When a unichip has been installed in an engine and mapped to that engine, you can tune the vehicle in any way you wish – you can program the unichip to lower the revolutions per minute (RPM) or you can program it as an immobiliser. Another chip can be set up for high boosts if the car has a turbocharged or supercharged engine. The unichip is a plug-and-play system, so if you decide to sell your vehicle, the unichip can be removed and installed in a different vehicle. But you need to remap for each individual vehicle’s unique specifications. Although the unichip was originally designed for diesel vehicles, modifications have been made to accommodate petrol vehicles. What is an exhaust?
An exhaust transports exhaust gases from the engine away from the passengers to the rear of the vehicle while conforming to noise and emission regulations. An exhaust was originally designed to let air flow from the engine to the rear of the vehicle as quietly as possible by using silencers. Silencer boxes are installed in the exhaust at strategic areas to maximise sound reduction while retaining drivability. They slow down the exhaust gases to reduce sound, and restrict the airflow out of the engine, which reduces power. A performance exhaust, on the other hand, expands airflow by increasing pipe diameter from standard size and reducing the size or number of silencers. This speeds up airflow, allowing the
❚❚❚❙❙❙❘❘❘ Everyday science
A car exhaust system. Image: http://hdabob.com/wp-content/uploads/2009/11/Exhaust.jpg
The author’s BMW 330ci. Image: Androniki Pouris
engine to run more efficiently. The exhaust will be louder than standard, creating a sportier engine noise, which enthusiasts love. A more free-flowing exhaust gives small power gains to the engine output. Observation and experimentation The motivation for this article came from my own experience of modifying my car after a friend spent a lot of money buying a supercharger. I started searching for an alternative and possibly more cost-effective method. I found that unichip and performance exhausts can both be available and effective. DASTEK, a large Pretoria-based supplier, assisted by providing all the information on devices, as well as other examples of modified vehicles. I decided to add a unichip to my own BMW 330 ci and was pleasantly surprised by the additional power – easily felt, although the actual increase was only 5%. The figures on the right show the power increase after modifications of three DASTEK vehicles. The three graphs show the power readings at the wheels as the engine revolutions change. In the first run shown, the vehicles are standard (without any modifications), while runs two and three show the power at the wheels after the modifications, which include the unichip and performance exhausts. You can see that as the modifications are made, the power of the vehicles increases. Table 1 summarises the findings at the highest revolution points, performance without modification (standard) and with the unichip
and performance exhaust. The two petrol cars (BMW and Golf) show an increase of approximately 10%. The diesel vehicle (Fortuner) shows an increase of 36.5%. It should be mentioned that the unichip was originally designed for diesel vehicles. Why do this? Many people would like to improve their car’s performance without spending a lot of money. Social media and films such as Fast and the Furious movies also contribute to the desire for speed. In my experience it is possible to significantly improve the performance of a car without spending more than R10 000 using the unichip and the performance exhaust systems. Adding superchargers or turbochargers could set you back between R60 000 and R100 000. So, for a relatively modest amount, you could improve your car’s performance by around 10% in petrol vehicles and 36% in diesel vehicles. In the future it would be interesting to find out if other external ECUs (e.g. Chipbox) provide equal or better power enhancement. Q Androniki Pouris is at the Faculty of Information and Communication Technology, Tshwane University of Technology. She likes driving fast cars! Acknowledgements The author would like to thank DASTEK for providing the relevant information as well as Mrs A Pouris, Prof A Pouris, Dr Inglesi Lotz, Mr M Piperakis and Mr P Roebuck for the valuable comments. References DASTEK, Unichip – Take control with the unichip q; accessed December 2013 at http://www.dastek.co.za/Unichip.pdf Toyota, 2013, Diagnosis Technician: Engine; Toyota South Africa Supercharging Performance Handbook, 2011, Jeff Hartman, page 182 The Turbo Hydra-matic 350 Handbook, 1987, Ron Sessions
BMW M3 power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK
VW Golf 1.4l power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK
Toyota 3000 Fortuner 4x4 power readings at wheels: standard, performance exhaust, unichip. Image: DASTEK
Table 1: Power increase from standard to modified versions Car type
10| 4 2014
LION DIARIES Working through the recent festive season enabled me to be out and about in the park seeing firsthand what works and what needs to be improved for our visitors, especially during peak season, when we welcomed some 160 000 visitors over 20 days, writes iSimangaliso CEO Andrew Zaloumis. Above: Mantuma Camp Hospitality Manager, Tyrone Mdiniso, says that visitors to uMkhuze are very interested to see the lions and are asking about them. Recent sightings included this sub-adult in a tree. Local tour guide Patrick Mathe commented, 'I have come across the lions three times and while they initially scared me, I am now fine with them because I have been trained how to behave around them.'
Regular satellite updates (shown as yellow dots on the above map) indicate the movements of the lions over the past seven weeks following their release from the boma. Visitors interested in planning a drive around uMkhuze in the hope of seeing lions at some of their more regular haunts can download a tourist map off our website www.isimangaliso.com to see the tourist road network.
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ne of the things that struck me was the great interest in, and excitement over, the release of lions into the uMkhuze section of iSimangaliso Wetland Park and the elephant herds in the new Western Shores. The feedback received from visitors and locals I met in and around the park, by email and on Facebook postings, has been tremendous and is appreciated by park staff who have worked diligently to make it happen. Patrick’s sentiments reminded me of what iSimangaliso’s Park Operations Director, Herbert Mthembu, who lead the Ezemvelo and iSimangaliso lion re-introduction team, said as we stoically waited outside the bomas on the 4 December to witness the lions’ release: 'When we talk to community members, especially the elders, they remember interacting with lions and sharing the river water. In those days it was customary not to come home late, and the saying was that if you did so, you would meet lions…to have lions once again in uMkhuze is bringing back that culture of respect for nature and, at the same time, listening to the wisdom of the elders. Community members are so excited and looking forward to seeing the uMkhuze section regaining her glory!' Since their release into the park on 4 December 2013, some 44 years since lion were last seen in the area, the four lions (an alpha female and three sub-adults) have remained together as a pride – evidenced by the parallel movements of their satellite tracking collars. The collars, paid for through the iSimangaliso Rare and Endangered Species Fund, which annually raises money for species conservation through iSimangaliso Eco-Series events such as the iSimangaliso MTB 4Day, iSimangaliso Sodwana Bay Shootout and iSimangaliso St Lucia Half Marathon, are proving useful in monitoring the lion movements remotely and via telemetry, allowing monitors to stay abreast of their location. The lions spent five weeks in the boma at uMkhuze. Finally, the long-awaited day arrived to let the big cats loose. The boma gate was opened in the late afternoon; we took up positions in our vehicle a fair distance away,
Giraffe on the Western Shores, and their many youngsters, are my personal favourites. They seem to be particularly appreciative of the new signage that charts out the routes and visitor attractions. Installing a signage system that is fit for purpose is no small challenge in a 220 km long park which includes almost 9% of South Africa’s coastline where signs are viewed by elephant, rhino, hippo and buffaloes as convenient rubbing posts and useful toothpicks. A great deal of thought, consultation and experimentation has gone into the development of these information, direction and compliance signs, using innovative materials to handle corrosive sea breezes, new technology, internationally recognisable symbols and the correct and authentic use of indigenous place names park-wide. 2014 will see the much-needed re-signing of the whole park.
trained our long camera lenses and patiently waited. And waited… but the Kodak moment we had hoped for did not materialise. After several hours of eager anticipation for the grand exit, it became clear to us that they would leave on their own schedule and we respectfully left the boma (and mosquitoes), a reminder that wild animals are wild and cannot be coerced! With no-one there to witness the historic moment, the satellite tracking collars recorded that the lions left the boma late that night and headed in a southwesterly direction (considered a good sign as this was the opposite direction from Tembe Elephant Park, from whence they had been moved). Ezemvelo’s uMkhuze conservation manager Eduard Goosen told me a few days later that the lions made their first kill, a buffalo, on their first day out of the boma. They then established a range in this vicinity for several weeks, taking up residence in riverine bush along a drainage line in the lee of the Lebombo Mountains. Movements over this period indicate that the homing instinct commonly witnessed in translocated lions post-release has been ‘broken’ and that the lions are settling into their new range. On the evening of the 18 December the cats were seen going after a male wildebeest but, alas, the lions went hungry as the wily wildebeest escaped the ambush. Shortly after Christmas day they began moving eastwards, crossing the main visitor road between Mantuma camp and eNxwala Vista Point. In the wee hours of 28th December, tracking showed a flurry of activity that suggests a possible kill to the east of the road. This kind of movement is to be expected as part of postrelease exploratory behaviour as the lions begin to learn their surroundings and orient themselves spatially. They need to know the location of crucial resources such as water sources, shade and vantage points. After splitting up for a while they rejoined and for several days in early January
While uMkhuze has had its fair share of excitement, the newly opened Western Shores section with its three elephant herds is not to be outdone. These magnificent pachyderms were exceptionally tourist-friendly over the festive season, with many wonderful sightings. Just like the predators, elephants are a special draw for many people and the number of tourist vehicles making the short day trip from St Lucia or Hluhluwe to this section is growing steadily.
made much use of the gravel roads south of kuMasinga Hide. It appears that they enjoyed a New Year's feast in the area between the uNyakaza and iNsumo streams (see map). A couple of days later (3 January), they followed the tar road north and branched off east towards iNsumo pan onto the gravel road for some distance, before heading west again. In recent days, the lions decided to investigate the northeast of the park, tacking off towards KuMahlala Hide, where visitors taking a drive along the River Loop may have been fortunate enough to spot them. However, on the latest downloaded recording (21 January 2014) they were once again quite close to the Lebombo Lookout Tower and it would probably be in this general area that tourists have the best chance of sightings. Tarik Bodasing, Ezemvelo’s iSimangaliso-based ecologist, confirms that this pattern of 'random' large movements followed by prolonged residence in an area is fairly typical of translocated lions. Current sightings by the priority species monitors indicate that the cats are calm and relaxed around vehicles, another positive aspect from a tourist perspective. Habituation of the lions to vehicles while in the boma is crucial and will be done in a similar manner for the upcoming introductions of two mature males followed by two mature females over the next few months. As an added bonus, the sharp increase in the number of carcasses (mainly wildebeest) has resulted in increased vulture activity in the vicinity! This is all part of the benefit of reinstating large carnivores to a system. More exciting sightings! It is fitting to conclude by thanking Mr Rudolph van der Veen of Allied Nutrition for his festive season donation to the iSimangaliso Rare and Endangered Species Fund in lieu of an annual Christmas party for his suppliers and customers. This is hugely appreciated by iSimangaliso and the money has been used to purchase much-needed rhino foot collars and horn transmitters. 2014 will see the fund focus on lions, eland and rhinos. q If you are interested in contributing to the preservation of these and other key species in our most magnificent marine and terrestrial world heritage site, please contact Debbie Cooper or me by email: email@example.com or firstname.lastname@example.org, or telephonically on 035 5901633.
10| 1 2014
Lake St Lucia on the road to recovery iSimangaliso Wetland Park was listed as a world heritage site in 1999 for several outstanding universal values, a key component being its ecosystems and ecological processes that include the unique Lake St Lucia system, also a Ramsar site (wetland of international importance). Pictured above: The uMfolozi River on the left, connected by a spillway to the Lake St Lucia estuary on the right. 'The re-connection of the uMfolozi to Lake St Lucia is producing encouraging results, with the restoration of Lake St Lucia well on its way. iSimangaliso remains committed to this new strategy, which sees the management of the estuary with minimum intervention. Our ultimate aim in the restoration of Lake St Lucia is to protect iSimangaliso’s World Heritage values without setting up a management regime that includes endless manipulation.' Andrew Zaloumis, iSimangaliso CEO.
For the first time in ten years the salinity gradient in the system is more typical of estuarine conditions with low salinities in the upper estuary (e.g. Lister's Point, Fani’s Island) and more marine conditions within the lower estuary (Narrows). Red areas indicate high salinity, Orange to yellow indicate mid-range salinities while blue indicates brackish and fresh-water conditions.
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n recent years, however, this system has been under severe strain, but the new iSimangaliso Authority management strategy for the Lake St Lucia system sees a fundamental shift in past management practice. As part of this strategy the uMfolozi River was encouraged to re-link to Lake St Lucia in July 2012. This led to the opening of Lake St Lucia to the sea, with many positive results. These include a return to salinities more typical of an estuary and the reappearance of fish and prawns, which can now enter the lake from the sea. Consistently good rains since September 2012 have continued to maintain high water levels in the lake, complementing the new management strategy. The joining of the two systems marks the end of a management approach which has kept them separate for the last 62 years, in the belief that sediments carried by the uMfolozi posed a threat to the lake (see 'Lake St Lucia: Understanding the problem and finding the solution' on www. isimangaliso.com). Because the uMfolozi River provides about 60% of the lake’s fresh water, the separation of the two systems deprived the lake of a significant inflow of fresh water. The loss of the uMfolozi also altered the movement of sediments in the mouth area and affected the natural opening and closing of the St Lucia mouth. The implications of this management approach became evident during the drought of 2001 – 2010, the worst in living memory. During this period, the
lessening of the uMfolozi’s influence on the estuarine and marine environments caused the St Lucia mouth to close (2001 – 2012), with detrimental effects on the marine, estuarine and lake ecosystems. The results of recent multi-disciplinary science undertaken under the auspices of iSimangaliso have given us a better understanding of the uMfolozi’s hydrological and ecological importance. The uMfolozi influences the opening and closing of the St Lucia mouth, the system’s overall water and salinity balance, and the movement of marine and river sediments which are a natural component of the estuarine environment. Following the joining of the two systems, modelling exercises suggest that the estuary will be open to the sea more often than it will be closed, and that the uMfolozi River exerts a necessary influence on the overall health of the St Lucia system. When the uMfolozi River rejoined the Lake St Lucia system on 6 July 2012 via a beach spillway, large volumes of water entered the Narrows and northward into the lakes for a period of two months. The September 2012 rains caused the uMfolozi River to flow strongly, and to breach the sandbar and create an open mouth into the joined system. Good spring and summer rains, and the newly configured outlet to the sea have resulted in high water levels, and a single, inter-connected water body throughout the 70 km lake system. The exciting changes being recorded as a result indicate that natural processes are being restored and that the estuary is recovering. iSimangaliso will continue to monitor the system closely. While it is likely that the mouth will continue to move northwards during summer, the dynamic impacts of river flow and wave action mean that the mouth could be positioned anywhere between Maphelane and St Lucia. 'Studies that refine our understanding of the lake are well underway. These will also propose management interventions that reflect this improved understanding. Our goal is to restore the long-term hydrological and ecological functioning of Lake St Lucia. This multi-disciplinary study is supported by iSimangaliso’s Global Environment Facility (GEF) Project and will be completed in the next six months. The studies are being run in tandem with stakeholder participation,' says Zaloumis. Over the past year, a number of changes have been observed in the system. Rainfall Since last July, when iSimangaliso implemented its strategy to allow the uMfolozi River to join Lake St Lucia, the area has experienced good rainfall, boosting the restoration of the Lake St Lucia system. A total of 1 505 mm of rain was received in St Lucia town over the past year (October 2012 - October 2013). Good rains (540 mm) fell during the spring and summer of late 2012 and early 2013 with this trend continuing through autumn and winter 2013 (270 mm and 150 mm respectively). The first two months of spring 2013 yielded good rains with 185 mm recorded at St Lucia, and the trend continues. Good rains have also fallen in the five river catchments
The jetty at Charters Creek, previously left high and dry, indicates the current water level.
Lake St Lucia is functioning as a nursery area once more, allowing marine migrants to complete their estuarine-dependant life-cycles as depicted in the graphic above.
Above is a view of the inundated Makakatana Bay at the top of the Narrows looking towards the eastern shores of the lake, with welcome rain clouds over the St Lucia system during late summer 2013.
that flow into the lake. This has resulted in significant changes to the current ecological state of the whole Lake St Lucia system which stretches for 70 km from Maphelane in the south to the uMkhuze swamps in the north. Current state of the system Water levels
The strongly flowing rivers have resulted in dramatic and sustained increases in the water levels throughout the lake system. The uMfolozi has remained consistently joined to 10| 1 2014
the dynamic forces at play in the mouth area, where strong river flows and tidal currents move beach sediments easily. Tidal exchange of water occurs during the high spring tides and even some of the higher neap tides, allowing both river and seawater to enter the estuary. Salinity
The above sequence shows the gauge plate at the St Lucia bridge over the past 18 months. Water level increases (left to right) are clearly indicated in moving from July 2012, August 2012 and December 2012. The water level in the October 2013 and Dec 2013 readings (on the right) are lower, reflecting the now open mouth condition. With an open mouth the lake level has reached a new equilibrium that is linked to tide levels. On a high tide the water levels at the bridge will be higher than at low tide.
Salinity in the northern parts of the system declined sharply over the summer (see graph below) in response to the freshwater inputs and rising water levels with a maximum of 15 recorded in False Bay (seawater is 35). Salinities in these northern parts had previously been well above sea water (100+) due to the lack of freshwater input to these areas and the high evaporation levels. The lower parts of the system were fresher because of the narrower, on average deeper channels, as well as the freshwater input from the uMphathe River, which has kept salinities low. This is an unusual condition to have for an extended period in an estuary as salinities are usually higher near the mouth, where the sea has the greatest influence and lower at the head of an estuary. This pattern has now begun to shift with salinity increasing in the mouth area and decreasing in the upper areas of the lake. Plant and animal responses
Salinities recorded at various stations within the Lake St Lucia system show a reversed salinity gradient until June 2013 and thereafter a more typical salinity gradient for an estuarine system - where salinities at the mouth are higher than those at in the north, such as Lister's Point.
the Lake St Lucia system; its high water volume entering Lake St Lucia for over 14 months for the first time in 60 years. As a result of the loss of uMfolozi water and the below-average rainfall during 2002 - 2010, the lake was divided into four distinct water bodies and disconnected from the Narrows. The lake system is now one continuous water body from the mouth area near Maphelane to the uMkhuze wetlands in the north. Water levels in the system are high and above mean sea level. This increase in water volume has resulted in a change in living conditions for the plants and animals and has significantly increased habitat diversity and functionality throughout the system. Mouth state
Because of the outflows from the uMfolozi River and the tidal currents, the estuary mouth has remained open since September 2012, creating a direct connection between the Lake St Lucia system and the sea via the beach spillway for the past 15 months. The beach spillway has been widened by 28
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This change in water levels and salinity led to some rapid changes to the animal species found in the lake. For example, a small (2 mm long) brackish water mussel, Brachidontes virgiliae, responded quickly to the fresher conditions in False Bay and colonised the newly inundated shoreline vegetation in large numbers. These animals were easily seen in the shallows around the lake forming clumps on the sediment and the plants covered by water. By contrast, the more brackish conditions developing in the Narrows have resulted in significant densities of river prawns, Macrobrachium spp. being recorded by researchers working in the system. Changes to the aquatic and shoreline vegetation in response to these new conditions will be slower. Beach walkers would, however, have noticed towards the end of May 2013 vast numbers of the fruits of the white mangrove, Avicennia marina, lining the intertidal areas around the mouth. This tree fruits heavily in the autumn and this is part of the dispersal mechanism of these estuarine trees. Seeds that are washed out of the mouth into the sea are transported along the coast so that mangrove colonisation can take place in other suitable estuaries, providing an input of new seed stock to adjacent systems. During the last summer (up to February 2013) the intertidal habitats at the mouth and other shoreline areas of the lake hosted a large variety and number of migratory wading birds attracted by the rich food resources present in this area. This group made up almost half of the 50 000 birds that were recorded in the whole lake system during the summer. The most obvious species found in the lake throughout the year were the flamingos, pelicans and ducks that took advantage of the increased habitat made available by higher water levels. Towards the end of spring the migratory waders returned to the system from the
❚❚❚❙❙❙❘❘❘ News Jellyfish drones coming? New flying machine moves like sea creature Courtesy of The Royal Society and World Science staff
The small brackish water mussel, Brachidontes virgiliae, which is usually found in the upper reaches of estuaries.
Scientists have devised a little flying machine that moves like a jellyfish in water. The only problem is it cannot carry the weight of a battery for the motor, so it has to remain attached to a tiny cord – but that should change, the designers predict. Technology often mimics nature in its quest for efficient, stable and manoeuvrable flight. Engineers have often taken inspiration from insects in the past 20 years, but machines with insect-like flapping wings have suffered some stability problems. The team developed a craft with four flapping wings that are pushed in and out in pairs. Wings on opposite sides of the machine flap simultaneously, with the second pair of wings following close behind. This allows the coneshaped machine to generate lift. ‘This design is reminiscent of the swimming motions of jellyfish,’ wrote the scientists, Leif Ristroph and Stephen Childress of New York University. They suggest the wing motion generates a jet flowing downwards, pushing the machine up, like the domed ‘bell’ jellyfish use to propel themselves. The findings are published in the Journal of the Royal Society Interface. Source: World Science, http://www.world-science.net
Real jellyfish. Image: Wikimedia Commons Propagules (fruits) of Avicennia marina in the intertidal zone of the mouth area.
Flamingos foraging in the newly inundated shoreline vegetation; this new habitat has been made available as a result of the raised water levels.
Palaearctic and began feeding in the intertidal areas at the mouth. iSimangaliso scientific studies The iSimangaliso Authority will continue to monitor the situation and investigations are well underway to find a long-term solution to the hydrological and ecological issues facing this important estuary system. This multi-disciplinary study is supported by the iSimangaliso Global Environment Facility (GEF) project. Q
New upgrade gives SANSA the international edge A recent Ka-band antenna upgrade is putting SANSA Space Operations at Hartebeesthoek in a uniquely competitive position to monitor a new wave of satellites launched over the southern hemisphere. In 1997 Hartebeesthoek installed the first Ka-band tracking, telemetry and command antenna in order to support the launch of a US Ka-band satellite constellation which broadcast to three American television networks. Installation and staff training on the antenna took nine months. For the next 15 years, a small part of the Ka-band spectrum was used, and only irregularly. The Ka-band has recently become more popular as a satellite frequency, prompting SANSA to invest in an upgrade which will enable the Space Operations team to support more launches and in-orbit testing campaigns. Having started in January 2014, the project includes the replacement of the antenna feed horn and all the equipment for receiving and transmitting the full commercial Ka-band. Acceptance testing has been completed and the antenna is ready for its first mission. By updating the antenna, SANSA is able to offer clients the entire range within the Ka-band frequency, thus creating new possibilities for international business and partnerships. The Ka-band antenna. Image: SANSA
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WALTER SISULU UNIVERSITY Walter Sisulu University offers fully accredited diplomas, degrees and postgraduate studies in a wide range of science programmes in its Faculty of Health Sciences and Faculty of Science, Engineering and Technology: Faculty of Health Sciences: MBChB; B Cur (Basic); Bachelor of Medical Sciences (Physiology, Biochemistry or Microbiology); Bachelor of Medical Clinical Practice; Bachelor of Social Work; Bachelor of Science in Health Promotion. Faculty of Science, Engineering and Technology: National Diplomas, degrees and postgraduate studies in Chemistry & Chemical Technology, Environmental Sciences, Physics, Biological Sciences (Pest Management), Botany, Zoology, Information Technology & Computer Science, Engineering - Civil, Electrical, Mechanical, Construction Management & Quantity Surveying, Applied Statistical Science, Mathematics, Consumer Science: Food & Nutrition as well as technological programmes in Fashion and Art. For affordable, fully accredited, quality higher education contact us today and apply before 31 October. Faculty of Health Sciences: Tel: 047 502 2111/2844 (Mthatha) Faculty of Science, Engineering and Technology: Mrs GK Lindani-Skiti, Tel: 043 702 9257, Fax: 043 702 9275, E-mail: email@example.com Offered at Buffalo City (East London), Butterworth and Mthatha Campuses.
9| 3 2013
Nelson Rolihlahla Mandela 8 July 1918 – 5 December 2013
Nelson Rolihlahla Mandela. Image: http://meritocracyparty.org
s 6 December 2013 dawned over a world still numbed by the news of the death of Nelson Mandela, a star flared up in the Centaurus constellation. Called a nova, a classical nova results when two stars orbit close enough to cause nuclear fusion that lights up the sky. ‘Nova Centauri 2013’, was spotted 3 Tuesday December for the first time over Australia, and peaked on Friday 6 December. It is said to be the brightest nova recorded so far this millennium. In 1918, another star flared and peaked. It was the brightest nova of the twentieth century and possibly the brightest ever recorded. It is known as V0603 Aquilae or Nova Aquilae 1918 – flaring to its brightest around 18 July 1918. Rolihlahla Mandela, Nelson Mandela, Madiba, Tata – a man known by many names and with many qualities. He was a lawyer, an activist, a prisoner of conscience, a peacemaker and negotiator, a statesman, the father of a nation, and an icon who inspired people around the globe. He was a man of conviction. He was unshakeable in his beliefs, as expressed in 1964: ‘I have cherished the ideal of a democratic and free society in which all persons live together in harmony and with equal opportunities. It is an ideal which I hope to live for and to achieve. But, if needs be, it is an ideal for which I am prepared to die’. Nelson Mandela’s life is also a testimony to perseverance. The persistence in doing something despite difficulty or delay.
He was a lawyer, an activist, a prisoner of conscience, a peacemaker and negotiator, a statesman, the father of a nation, and an icon that inspired people around the globe. He was a negotiator – Nelson Mandela was ‘the greatest negotiator of the twentieth century,’ wrote Harvard Professor Robert H Mnookin in his book, Bargaining with the Devil, When to Negotiate, When to Fight. In the chapter on Mandela, Mnookin cites Mandela’s patience, tenacity, pragmatism, and strategic thinking. He was a peacemaker and could forgive. His life and legacy personify forgiveness and the best in human values. But above all, Nelson Mandela, Madiba, was humble – a rare and refreshing quality. He knew no masters and no servants. All are equal. Despite being revered as a legend and icon in his own lifetime, he recognised human frailties. He called Her Majesty, the Queen, ‘Elizabeth’, simply because she called him ‘Nelson’. As Nova Centauri continues to light up the skies, may Nelson Mandela rest in peace. And let the legacy of Madiba shine on. Q 10| 1 2014
9| 3 2013
Bio-pesticides: the bigger picture
Africa’s most powerful microscopes are being used to boost the use of bio-pesticides in South Africa’s citrus industry, writes Nicky Willemse Nelson Mandela Metropolitan University Master’s student Patrick Mwanza, 26, is combining cutting-edge physics with real citrus farming practices to encourage farmers to wage an environmentally friendly war against the false codling moth, one of the country’s main citrus pests. With the majority of South Africa’s oranges exported to Europe, citrus farmers have to make sure their products are completely pest-free. To do this, some are reluctant to use anything but traditional chemical pesticides – but Mwanza is hoping his research will lead to greener farming. Since 2004, the bio-pesticide Cryptogran – a product of River Bioscience, South Africa’s leader in biological pest control – has been used effectively to control the false codling moth. Cryptogran is essentially a concentrated form of a naturally occurring virus to which the moths are susceptible. Sprayed on the oranges, moth larvae that are newly hatched from eggs laid on the oranges ingest it and die. Without pesticides, the larvae would burrow into the navel of the orange, ultimately causing ‘fruit drop’, said Mwanza’s supervisor Dr Gill Dealtry, a senior lecturer in the department of biochemistry and microbiology. ‘It’s absolutely critical that the moth is controlled. If just one orange is infested, an entire consignment may be deemed unsuitable for export,’ said Dealtry. The challenge when it comes to Cryptogran is that sunlight diminishes the virus’s effectiveness over time and, like most pesticides, it has to be reapplied every few months. However, until now, there have been no hard and fast rules about how long the pesticide remains effective and how often it should be reapplied, with most farmers erring on the side of caution. Using the university’s new high-resolution transmission electron microscope (HRTEM) – the most powerful in Africa – and scanning electron microscope (SEM) as well as the Raman spectroscope, Mwanza is able to examine the minuscule virus molecules to their very core – with the aim of making the application of Cryptogran an exact science, leading to its optimal use and inevitably saving farmers money by preventing over- and under-spraying. It will also probably lead to the wider use of the bio-pesticide, which will have positive implications for the environment. Using samples from trial sites in the Sundays River Valley and also under UV light in the lab, Mwanza, who has completed a year of Master’s research, has been able to determine that the virus’s protective covering offers no protection from UV rays – and his next step is to examine the core of the molecule to determine how and when this internal structure changes. He has presented his findings at major microscopy conferences in South Africa. Driving his research is his passion for ‘science put to practical use’. ‘I’m a scientist helping the community.’ Mwanza’s research is being funded by Citrus Research International, the research arm of the South African Citrus Growers Association. Dealtry said: ‘This project provides an opportunity for unique collaboration between physics, biochemistry and role players in the citrus farming industry.’
‘Green’ pesticide research … Nelson Mandela Metropolitan University biochemistry Master’s student Patrick Mwanza and his supervisor Dr Gill Dealtry get to grips with a sample of baby oranges, which form part of Mwanza’s research on the biopesticide used to control the false codling moth. Image: Nicky Willemse
Citrus solution … Nelson Mandela Metropolitan University biochemistry Master’s student Patrick Mwanza conducts research on Cryptogran, a biological pest control for the false codling moth. Image: Nicky Willemse
Cheating at Comrades Mark Dowdeswell, who is a Comrades runner and a lecturer in mathematical statistics at the University of Witwatersrand, has statistically analysed the results from the Comrades Marathon – produced by Championchip. From this analysis, he suggests that runners are cheating on one of the world’s best-known ultramarathons. Mark bases this on analysis of the last two up runs to show the split differences in times for the two halves of the race through the entire field. In 2011 he found far more negative splits – meaning that
runners ran the second half of the race faster than the first – than in 2013 – which may be due to the extreme heat of 2013. However, in 2011 there was not one runner with a negative split of more than one hour – in 2013 there were three. The biggest negative split of all was shown by one runner who apparently ran the second half almost 1 hour 40 minutes faster than he ran the first half. The runnning world is convinced that this is evidence that this runner left the race route, climbed into a car and rejoined the race later to cross the finish line.
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ASSAf recognises outstanding meritorious service The Academy of Science of South Africa (ASSAf) has awarded Professor Robin Crewe the prestigious Gold Medal for Outstanding Meritorious Service at the launch of the Centre for the Advancement of Scholarship at the University of Pretoria. It is only the second time that the award has been bestowed since its inception in 2008. Crewe has served as President of ASSAf from 2004 to 2012. During this time, the Academy grew from a small organisation to a well-established academy that enables the generation of evidence-based solutions to national problems. ASSAf lauded Crewe for his ‘contribution to the establishment of ASSAf as a wellrecognised Academy within South Africa, the region, and internationally and for the roles that he has played in international Academy networks and bodies, all of which have enhanced the reputation of ASSAf’. Crewe is the Director of the Centre for the Advancement of Scholarship at the University of Pretoria. His current research
From left: Prof. Roseanne Diab, Executive Officer of ASSAf, Prof. Daya Reddy, President of ASSAf, Prof. Robin Crewe, Director of CAS and Prof. Cheryl de la Rey, Vice-Chancellor and Principal of the University of Pretoria. Image: ASSAf
is focused on chemical communication and social organisation in honeybees and
ASSAf recognises young South African scientists Two young scientists were also recognised in the AU-TWAS Young Scientists’ National Awards. These aim to recognise and reward the scientific achievements of young researchers working in Africa. The AU-TWAS Prize for Young Scientists in South Africa is managed by the Academy of Science of South Africa (ASSAf), on behalf of its partners, the African Union (AU), The World Academy of Sciences (TWAS) and the South African Department of Science and Technology (DST). The prize in the category Life and Earth Sciences was awarded to Prof. Landon Myer from the University of Cape Town. Prof. Cornie Scheffer from Stellenbosch University received the prize in the category Basic Sciences, Technology and Innovation. Myer is an Associate Professor in the Division of Epidemiology and Biostatistics of the School of Public Health and Family Medicine at the University of Cape Town. He is also Adjunct Associate Professor in the Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, USA. His specific research focus is on reducing the impact of HIV/AIDS on women’s, maternal and child health, particularly in the areas of prevention of mother-to-child HIV transmission and contraception for HIVinfected women. Scheffer is the founder of the Biomedical Engineering Research Group (BERG) at Stellenbosch University. BERG is currently one of the leading groups in South Africa for research in the field of biomedical engineering. He has co-authored more than 100 scientific papers and supervised a vast number of postgraduate students. At the same event, the Sydney
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Brenner Fellowship, administered by the Academy and supported by the Oppenheimer Memorial Trust, was awarded for postdoctoral studies in the molecular and cellular biosciences conducted at an advanced level in South Africa. The emphasis in the selection is on the excellence of the academic track record; evidence of unusual creativity and ingenuity in addressing scientific problems; both the novelty and feasibility of the proposed approach; and the quality, adequacy and appropriateness of the host environment. The 2014/15 Fellowship was awarded to Dr Anna Coussens, a postdoctoral research fellow at the University of Cape Town. She received her PhD from Queensland University of Technology, Australia, in developmental molecular biology. Thereafter she volunteered in Uganda with a medical students’ organisation, running health surveys in remote communities. This experience shaped her desire to become an infectious disease immunologist. She then moved to London, where she contributed significantly to a programme of work on vitamin D regulation of the immune response to tuberculosis. Now in Cape Town, she is defining how seasonal UVB patterns affect vitamin D levels in healthy young adults and how this impacts their immune response to HIV-1 infection. Top right: Prof. Cornie Scheffer from the University of Stellenbosch received the AU-TWAS Young Scientist Award in the category Basic Sciences, Technology and Innovation in 2013. Image: ASSAf Right: The 2014/15 Sydney Brenner Fellowship was awarded to Dr Anna Coussens, a Postdoctoral Research Fellow at the University of Cape Town. Image: ASSAf
ants, particularly with respect to worker reproductive regulation.
Our inner Neanderthal Two papers published recently in the journals Science and Nature suggest that although we did interbreed with the Neanderthals, the offspring of these matches probably had fertility issues. The two papers identify the slices of the genome that modern humans inherited from the Neanderthals – a group of hunter-gatherers who went extinct about 30 000 years ago. Our species, Homo sapiens, and the Neanderthals share a common ancestor who probably lived in Africa more than 500 000 years ago. The ancestors of Neanderthals were the first to move to Europe and Asia, while the modern human lineage stayed in Africa. When modern humans began to leave Africa less than 10 000 years ago, they interbred with the Neanderthals who had settled from Western Europe to Siberia. As a result, DNA from the two lineages started to mix again after a gap of half a million years, according to David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts, who led the Nature study along with colleague Sriram Sankararaman. Neanderthal genetic contributions We know that the two groups mated and that about 2% of the genome of people who are descended from Europeans, Asians and other non-Africans is Neanderthal – different people have different Neanderthal genes. It would appear that some of these genes are involved in fighting infections, while others are invovled with coping with radiation. But the latest studies are the first to identify a large proportion of the genome segments that humans inherited from Neanderthals. Joshua Akey, a population geneticist at the University of Washington in Seattle, who wrote the Science paper with colleague Benjamin Vernot, says that his team found about one-fifth of a Neanderthal genome spread across the publicly available genomes of 665 living Europeans and East Asians. Reich and his team estimate that they could put together about 40% of the Neanderthal genome from the sequences of 1 004 living people that they studied. The teams looked for Neanderthal genes that were particularly common in modern humans, a sign that the genes were useful to their new owners. Both groups identified a series of genes involved in the inner workings of cells called keratinocytes, which make up most of the outer layer of human skin and produce hair. Researchers think that it is possible that the Neanderthals were already adapted to the colder environments in Europe and that these genes helped modern humans to cope with the new climate after they arrived from Africa, but the research is highly speculative at present. Both studies
A reconstruction of a Neanderthal couple. Image: Wikimedia Commons
The distribution of Neanderthals in Europe. Image: anthropologyinpractice.com
found that there were many Neanderthal genes that are not found in modern humans, which suggests that these genes were harmful to modern humans and were eliminated from the gene pool as modern humans and Neanderthals continued to mate. Reich’s team, meanwhile, discovered that today's humans tend to have few of the Neanderthal genes that are activated in the testes or located on the X chromosome. In organisms such as fruitflies, such patterns are hallmarks of hybrid sterility, indicating that two populations are too distantly related to breed successfully. Modern humans and Neanderthals ‘were at the edge of biological compatibility’, Reich concludes, and their hybrids probably suffered high rates of infertility. ‘Neanderthals aren’t around, so you can’t do a mating experiment,’ says Daven Presgraves, an evolutionary biologist at the University of Rochester in New York. But the patterns that Reich’s team noticed are exactly what you would expect if their hybrids suffered from reduced fertility, he adds.
However, Presgraves was surprised that modern humans and Neanderthals, separated by only tens of thousands of generations, would already show signs biological incompatibility. Animals such as fruitflies typically need to be separated for much longer to evolve naturally into distinct species, he says. Sarah Tishkoff, a population geneticist at the University of Pennsylvania in Philadelphia, says that the studies rank as ‘some of the most exciting papers I’ve seen’. She adds that the work hints at the possibility of studying ancient-human genomes gleaned not from bones but from the DNA of contemporary populations. Such studies could be especially revealing in Africa. There, well-preserved samples of ancient DNA are scarce, and yet genome studies of today's inhabitants of the continent hint that although ancient Africans did not mingle with Neanderthals they may have interbred with other nowextinct groups. ‘We really need to be able to apply these methods to African populations,’ says Tishkoff. ‘Just imagine what we’re going to find there.’ Source: Nature News
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Making mammals easy Southern African Mammals made simple: Three easy steps to identification. By Doug Newman and Gordon King. (Cape Town. Struik Nature. 2013.) I think that most of us can pretty easily identify Africa’s big five – but these are not what you usually see when out on a walk in the country or wandering through your gardnen, unless you live close to a game park, of course. The challenge lies in identifying some of the lesser known mammals in the region, such as the various species of antelope, mongooses, genets and, of course, the primates. The book is designed not as a standard field guide, but as a visual guide that makes identification easier. Each species featured in the book is assigned to one of 14 distinct ‘family’ groups. In the context of this book, ‘family’ simply refers to a group of animals that share some broad features – it is not a taxonomic family. The three basic steps to identifying the unknown mammal are clearly laid out, with good diagrams in the form of silhouettes – first separating families, followed by separating the visual groups and finally identifying the species. The final identification relies on matching all three features in orange type or one feature in red in the visual groups – the text in the book reflects the colours. Each species is illustrated with a colour drawing that emphasises the distinctive features of the mammal. The book is lavishly illustrated with colour photographs, both of the species and their typical habitats. The book will be a handy guide to anyone visiting a game reserve, walking in the wilds – both for general readers and for wildlife enthusiasts.
Flowers as food 100 Edible and Healing Flowers: cultivating, cooking and restoring health. By Margaret Roberts. Photographs by Phyllis Green. (Cape Town. Struik Nature. 2014.) Anyone who enjoys good food will be familiar with the Margaret Roberts range of sauces, stocks and baked products – delicious! This book provides a wonderful overview of how the flowers that brighten your garden can also be made into tasty meals and could even help you 36
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with common ailments if used in the correct way. As the introduction to the book says, ‘There is nothing more appealing or exciting than creating a garden of flowers that can be eaten, incorporated in festivities, celebrations and feasts and used as medicines and cosmetics’. And there is a wonderful introduction to how to plan a garden, what kind of soil will be best, making compost and mulch and how to plant – from seedlings and seed. The plants are arranged in alphabetical order with colour photographs and some drawings for each species. There is a description of the plant, with something of the history of its use in medicine and cooking, followed by a range of recipes – both for meals alone or for a syrup, lotion or similar for medicinal use. There are also recipes for skin tonics and lotions, as well as a range of cooling drinks that can be made from many of the flowers. A lovely book for anyone who enjoys interesting and organic foods and would like a particularly useful garden.
World cuisine Culinary Herbs and Spices of the World. By Ben-Erik van Wyk. (Pretoria. Briza Publications. 2014.) This is a wonderful book for anyone who enjoys different varieties of food. Many world cuisines are based on distinctive uses of herbs and spices, most of which are now freely available across the world. Ben-Erik divides the world roughly into seven major ‘cuisine’ families – sub-Saharan Africa, the Middle East, South Asia (India and surrounding countries), East Asia (China, Japan and Korea), Southeast Asia (Malaysia, Thailand, Vietnam and Indonesia), Europe and its former colonies and the New World – a mosaic of fusion foods. The history of herbs and spices is fascinating, following the history of population movements around the world and the beginnings of global trade, and through this Ben-Erik explores the regions of origin and culinary traditions of his seven major cuisines. There is a section on cultivation, harvesting and processing, as well as on salad herbs and herb mixtures. Culinary herbs, spices and spice mixtures are each given separate coverage, as are seasoning
and condiments – providing an exellent summary of exactly what it is that we are eating in all these different cuisines. There is an excellent section on the chemistry of taste and flavour, which would usefully bring together some principles of aromatic organic chemistry. Each herb and spice is then dealt with in detail in alphabetical order, with a description, the plant, the origin of the plant, how it is cultivated and harvested and its culinary uses, along with a chemical formula if appropriate. There are no recipes, but the descriptions of the herbs and spices and of the cuisines should inspire some experimentation at least.
A glimpse of genius My Brief History. By Stephen Hawking. (London. Bantam Press. 2013.) There can be few physicists who are as familiar as Stephen Hawking. It is unfortunate that this familiarity is partly as a result of his major disability, resulting from motor neurone disease. He is regarded as one of the most brilliant theoretical physicists since Einstein and this modest little book is a testament to his characteristic humility and humour. The book takes readers on a journey from his boyhood in London shortly after the second world war to his years of international acclaim and celebrity. The book is filled with photographs that have rarely
been seen before. We see a different side of Hawking – witty and candid. His brilliance and enquiring mind led to his nickname of ‘Einstein’ at school and his description of struggling to get onto the ladder of academia shows that even the most brilliant still have to climb the ladder to recognition. He is frank about the challenges that opened up with his diagnosis of motor neurone disease at the age of 21 – astonishing that he is still with us today and almost certainly a testament to his tenacity of mind and spirit. It was the prospect of an early death – which fortunately did not materialise – that spurred him into the huge number of intellectual breakthroughs that he has made over the years – and these are not over yet.
How a scientist is made An appetite for wonder: The making of a scientist. By Richard Dawkins. (London. Bantan Press. 2013.) Richard Dawkins is well known for his prolific popular science writing and for his vehemently anti-religious philosophy – stemming from his love of science and the world around us. He grew up in Africa, in the colonial age, born to parents who were enthusiastic naturalists – and into a wider family that linked him to many accomplished scientists. As he said, biology was in his genes. In this first part of his autobiography he takes us back to his childhood in colonial Africa, where he was entranced by the exotic natural world around him, to his schools in England, where he was initially a fervent follower of the Church of England – which soon gave way to disaffection and teenage rebellion. At first music and the arts were his passion, but his arrival at Oxford stopped that. He describes this as the catalyst to his life – where vigorous debate in the dynamic Zoology Department of the time stirred his intellectual curiosity and creative thinking, resulting in the formulation of a radical new form of Darwinism and the publication of The Selfish Gene. Anyone who loves the natural world and is a biologist themselves will enjoy this account of one of the more controversial figures in science today. 10 |1 2014
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Back page science
Study: Even prisoners think they are nicer than most people Courtesy of the University of Southampton and World Science staff
Just about everyone thinks they are better than average – and that is true for convicted criminals as well, a study has found. Researchers found prisoners consider themselves more moral, kinder and more trustworthy than non-prisoners in their community. ‘If the prisoners self-enhanced by considering themselves superior to fellow inmates or community members on "macho" traits, such as toughness, I would not be surprised,’ said Constantine Sedikides of the University of Southampton, UK, who led the work. ‘However, they self-enhanced on prosocial traits – such as kindness, morality, self-control, and generosity,' he said. The study found that prisoners did not rate themselves as more law abiding than nonprisoners, but they did rate themselves as equal.
mushroom cloud, they explain. Three things happen in sequence after a bottle is bumped, they found. First, ‘compression waves’ appear – an area of the liquid becomes compressed, and the area of compression starts travelling, bouncing when it hits a wall. These waves cause the bubbles to burst at the bottom of the bottle. They break up into smaller ones, forming foam. Because these weigh less than the liquid surrounding them, they move to the surface so quickly that the final result is like an explosion. ‘Those clouds of foam are very much like the mushroom cloud caused by a nuclear explosion,’ an author said – in one second, almost all of the beer shoots out of the bottle. The foam is there because the liquid cannot absorb all the carbon dioxide gas that is in there, he went on. ‘Usually, the CO2 escapes very slowly. But the chain of events set off by the blow to the bottle’ makes it much faster.' Source: World Science,
data from observations equivalent to over nine and a half days worth of time, taken between 1999 and 2012. In this image, the lowest-energy X-rays Chandra detects are in red, while the medium-energy X-rays are green, and the highest-energy ones are blue. It shows the spectacular jet of outflowing material – seen pointing from the middle to the upper left – that is generated by the giant black hole at the galaxy’s centre. This new high-energy snapshot of Cen A also highlights a dust lane that wraps around the waist of the galaxy. Astronomers think this feature is a remnant of a collision that Cen A experienced with a smaller galaxy millions of years ago. Source: NASA Centaurus A. Image: NASA
Source: World Science, http://www.world-science.net
Guys: Get married for the sake of your bones, but wait until you're 25
Foam on the top of a beer. Prisoners. Image: Wikimedia Commons
Image: Wikimedia Commons
Beer foam explodes like a ‘mushroom cloud’, scientists find
A new look at an old friend
Courtesy of Universidad Carlos III de Madrid and World Science staff
Scientists say they have explained why beer foams up so quickly when a bottle is bumped. The foam begins forming at the bottom and bursts upward, not unlike a
Just weeks after NASA’s Chandra X-ray Observatory began operations in 1999, the telescope pointed at Centaurus A (Cen A, for short). This galaxy, at a distance of about 12 million light years from Earth, contains a gargantuan jet blasting away from a central supermassive black hole. This new image of Cen A contains
Marriage is good for the health of men's bones – but only if they marry when they are 25 or older, new UCLA research suggests. In a study published online in the peer-reviewed journal Osteoporosis International, researchers found evidence that men who married when they were younger than 25 had lower bone strength than men who married for the first time at a later age. In addition, men in stable marriages or marriage-like relationships who had never previously divorced or separated had greater bone strength than men whose previous marriages had fractured, the researchers said. And those in stable relationships also had stronger bones than men who never married. Source: UCLA
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Three playing cards sit on a surface in a row. There is a two to the right of a king. A diamond will be found to the left of a spade. An ace is to the left of a heart. A heart is to the left of a spade. Now, identify all three cards.
Answer to Maths Puzzle no. 27: Solution 15h58 because at 15h59 it was half full and at 15h58 it was a quarter full.
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