Science Science for for South South Africa Africa
ISSN 1729-830X ISSN 1729-830X
Volume 8 • Number 4 • 2012 Volume 3 • Number 2 • 2007 R29.95 R20
Alan Turing: the father of computing How are codes cracked? Why are smarphones smart?
How did coal form? Out of Africa with spears and knives Sc A c Aacdaedmeym yo fo fS c i ei ennccee ooff SS o u u tt hh AAffrri c i ca a
Research that can change the world
Impact is at the core of the CSIR's mandate. In improving its research focus and ensuring that it achieves maximum impact in industry and society, the organisation has identified six research impact areas: Energy - with the focus on alternative and renewable energy. Health - with the aim of improving health care delivery and addressing the burden of disease. Natural Environment - with an emphasis on protecting our environment and natural resources. Built Environment - with a focus on improved infrastructure and creation of sustainable human settlements. • Defence and security - contributing to national efforts to build a safer country. • Industry - in support of an efficient, competitive and responsive economic infrastructure. • • • •
Alan Turing – the father of computing Quest celebrates Alan Turing’s birth, 100 years ago 6
Public key cryptography – or why you can buy things online Simon Singh How is it possible to have secure online transactions?
How smart is a smartphone? Gary Marsden How smart phones make people’s lives easier
Early technology and human complexity Early modern humans developed potentially lethal technology, which they took with them on their trek out of Africa
Contents Volume 8 • Number 4 • 2012
The life of coal: ancient forests that power our nation
Blast protection Genevieve Langdon Designing to protect
Rose Prevec Do you know where coal comes from?
A right to safe water supplies Anél du Plessis and Louis Kotzé
Access to a safe supply of water is a basic human right that is upheld in South Africa 12
A breakthrough for HIV research Once again, South Africa is at the forefront, with a breakthrough that may revolutionise HIV vaccine research
Kirsty Robinson, Jessica Kavonic and Mischa Minne As our climate changes, so do the patterns of disease
Conserving marine life in Mozambique
Andronike Pouris The wealth of life under the warm waters of Mozambique – conservation in action 18
Changing disease patterns
Laser technology illuminates stem cell research Thulile Khanyile and Patience Mthunzi The use of lasers in stem cell research may make transplants unecessary
Hyrdogen fuel cells: for electricity and transport Jan Smit The continuing story of hydrogen fuel cells
Nicolas-Louis de la Caille Ian Glass
RSA Data Security Inc.
The extraordinary life of one of the first scientists to visit South Africa
Improving community health Juanette John Simple ways of safeguarding our environment contribute to a community’s health
Local science A future in mathematics – p. 25 • ASSAf news – p. 47 • SAASTA news – p. 47
Back page science • Mathematics puzzle
Quest 8(4) 2012 1
Science Science for for South South AfricA AfricA
ISSN 1729-830X ISSN 1729-830X
Volume 8 • Number 4 • 2012 Volume 3 • Number 2 • 2007 r29.95 r20
Alan Turing: the father of computing How are codes cracked? Why are smarphones smart?
How did coal form? Out of Africa with spears and knives Sc A c AAcdAedmeym yo fo fS c I eI eNNccee ooff SS o u u tt hh AAffrrI c I cA A
Images: Wikimedia Commons, Erich Fisher, childfund.org.nz
SCIENCE FOR SOUTH AFRICA
Editor Dr Bridget Farham Editorial Board Roseanne Diab (University of KwaZulu-Natal) (Chair) John Butler-Adams (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) Penny Vinjevold (Western Cape Education Department) Correspondence and The Editor enquiries PO Box 663, Noordhoek 7979 Tel.: (021) 789 2331 Fax: 0866 718022 e-mail: email@example.com (For more information visit www.questinteractive.co.za) Advertising enquiries Barbara Spence Avenue Advertising PO Box 71308 Bryanston 2021 Tel.: (011) 463 7940 Fax: (011) 463 7939 Cell: 082 881 3454 e-mail: firstname.lastname@example.org Subscription enquiries Patrick Nemushungwa and back issues Tel.: (012) 349 6624 e-mail: Patrick@assaf.org.za
Science & society
he introductory article in this issue of Quest is a brief account of a very important life – that of Alan Turing – who is generally called the ‘father of computing’. Turing’s work on breaking codes and artificial intelligence and the then revolutionary machines that he constructed in his pursuit of the mechanisation of mathematics paved the way for the computers of today. And not just computers – smartphones, iPads and other tablets and a host of other technology that we now take completely for granted. He was a truly innovative and far sighted individual who should have gone a lot further – living to see far more of the fruits of his remarkable brain. But Turing died at 42. He killed himself because society could not accept his homosexuality. Elsewhere in this issue we look at further evidence that modern humans evolved and initially prospered in southern Africa before making the truly remarkable journey into the rest of the world. Turing, computing and homosexuality – early modern humans and Afrian origins – what have these to do with each other you may ask? My point is that science is the only true leveller in society today. Since Turing died, homosexuality has been legalised in most progressive countries around the world, but enormous predjudice still remains against those who are different from what is considered the ‘norm’. And there is now incontrovertible evidence that we all originated in Africa and that the concept of ‘race’ is completely artificial. But racial predjudice and tension remains a major force in the world today – manifesting also as religious intolerance – leading to increasing pockets of conflict around the world. This is where science and society can and should meet. As we understand more and more about the world around us and the people in it, we increasingly see just how artificial barriers such as ‘race’, sexual orientation and religion are. The concept of the whole human race belonging to one population is not just a spiritual one, it is a scientific one. We are all one people under the Sun. As we come to the end of another year, let’s take that thought with us into 2013.
Bridget Farham Editor – QUEST: Science for South Africa
Copyright © 2012 Academy of Science of South Africa
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Design and layout Creating Ripples Graphic Design Illustrations James Whitelaw Printing Paradigm
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the father of computing Alan Turing was born 100 years ago. He is arguably the person who was responsible for computing as we know it today. Quest takes a look at his life.
lan Mathieson Turing was born on 23 June 1912. He was a British mathematician, logician and cryptanalyst. He was also probably one of the first computer scientists. A logician is someone who studies ways of reasoning and the use of valid reasoning – the use of logic.
It was Turing who formalised the concepts of algorithm and computation, using the Turing machine. The Turing machine is considered to be a model of a general- purpose computer. In mathematics and computer science, an algorithm is a step-by-step procedure used for calculations. An artistic representation of a Turing machine.
In 1936 Alan Turing described what became known as the Turing machine – although he called it an a-machine (automatic machine). The Turing machine was not intended as practical computing technology, but rather as a hypothetical device that represented a computing machine. Turing machines help computer scientists to understand the limits of mechanical computation.
A complete and working replica of a bombe at the National Codes Centre at Bletchley Park. ▲ ▲
Codebreaking Alan Turing is probably also best known as a codebreaker. During World War II Turing worked at Bletchly Park, Britain’s codebreaking centre. He was head of the unit that was responsible for breaking the German navy codes. Within weeks of arriving at Bletchley Park, Turing had designed an electromechanical machine that could find settings for the Enigma machine. The Enigma machine was invented by a German engineer, Arthur Scherbius, at the end of World War I. The machine was used for the encryption and decryption of secret messages. This was the start of the allies’ ability to decypher German messages, which was vital to the war effort, particularly to keeping tags on the German navy’s attempts to disrupt shipping in the North
Image: Wikimedia Commons
Image: Wikimedia Commons
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The military Enigma machine.
Image: Wikimedia Commons
A plaque marking Turing’s home at Wilmslow, Cheshire, UK.
The Alan Turing memorial in Sackville Park, Manchester, UK.
Image: Wikimedia Commons
Image: Wikimedia Commons
Atlantic. The machine was called a bombe and searched for possible correct settings used for an Enigma message. The bombe performed a chain of logical deductions for each possible setting of the rotors of the Enigma machine, moving through the settings and discarding unlikely ones, until a few possible settings remained, which could be investigated in detail. During the war, Turing developed several different types of codebreaking machines, all in response to successive versions of German code machines. Early computers and the Turing test After the war Turing turned to computer design, initially working on the ACE (Automatic Computing Engine) at the National Physical Laboratory. In 1946 he presented his ideas for the first detailed design of a stored-program computer – one that stores program instructions in an electronic memory. A full version
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of Turing’s ACE was never built, but there are a number of computers around the world that owe much to it. Turing returned to an academic life in 1948, when he started to work on artificial intelligence. He proposed an experiment that became known as the Turing test – an attempt to define a standard for a machine to be called ‘intelligent’. The idea was that a computer could be said to ‘think’ if a human interrogator could not distinguish it from a human being when talking to it. In his paper on this test, Turing suggested that rather than building a program to simulate the adult mind, it would be better to produce a simpler one to simulate a child’s mind and then educate it. In 1948, Turing and a colleague began writing a program for a computer that did not yet exist. By 1952, because he did not have a computer powerful enough to execute the program, Turing played a game in which he simulated the computer, taking about half an hour per move – the program
lost to one of Turing’s colleagues. The Turing test has remained a lasting contribution to the debate around artificial intelligence. The final years Alan Turing was a homosexual, which was illegal in Britain until the Sexual Offences Act of 1967 decriminalised this. In 1952 Turing was convicted of gross indecency and was given the choice of prison or probation with hormone treatment designed to reduce his sex drive. He chose the latter and suffered the humiliation of the sideeffects. This conviction removed his security clearance and he was barred from any further cryptography work for the British government. On 8 June 1954, Turing was found dead by his cleaner – he had died the previous day. A postmortem showed that he had died from cyanide poisoning and an inquest determined that he had committed suicide. ❑
IDC – financing South African innovation The IDC’s Venture Capital Strategic Business Unit (SBU) manages a R750 million fund providing equity funding to start-up companies for the development of globally unique South African Intellectual Property (IP) – this being the key criteria for any application.
Funding is provided in the form of ordinary shares and shareholder loans. There is no stipulated investment period, but the SBU’s objective is to achieve an exit opportunity within a reasonable time frame.
The funding provided by the SBU facilitates completion of the development, followed by the commercialisation of technology-rich products. These innovations and inventions most often stem from academic researchers who have developed their work to a point where they have a desire to become entrepreneurs; and innovators or inventors who want to move from tinkering with their ideas and prototypes in their backyards to fully commercialised businesses.
Through its investments, the Venture Capital SBU plays a proactive role in driving industrial development in South Africa, having a meaningful impact through the development of new entrepreneurs and shifting the focus from large companies to SMEs. This is achieved through sustainable development of more knowledge-intensive industries for long-term growth and job creation as prioritised in the Government’s New Growth Path (NGP). The unit continues to be a proactive, value-adding partner to its clients, capable of producing huge development returns to the benefit of South Africa’s economy and citizens.
The critical investment criterion for all Venture Capital projects is that the IP must be owned by the company and if not patentable, the product needs to provide a sustainable competitive advantage. The unit’s mandate allows for investment in projects across all industries, leading to sectoral growth and job creation. Recent South African inventions and innovations in the electronics, ICT, medical device and biotechnology sectors have proven particularly successful.
Funding for a project can reach a maximum of R40 million over several years, with the initial investment limited to R15 million. The IDC takes a minority shareholding of between 25% and 50% depending on the SBU’s valuation of the business and the amount of funding required. The start-ups stand to benefit from the further strategic support, guidance and advice provided through a partnership relationship with the IDC.
Telephone: 086 069 3888 Email: email@example.com To apply online for funding of R1 million or more go to www.idc.co.za
Public key cryptography – Every time you transact online, your payment details are sent using public key cryptography. Simon Singh explains how this is possible.
In an asymmetric key encryption scheme anyone can encrypt messages using the public key, but only the holder of the paired private key can decrypt. Security depends on the secrecy of the private key. Image: Wikimedia Commons Above right: Bletchley Park, an old country house that housed people and machines that were vital to the war effort in World War II. Image: Wikimedia Commons
Cryptography Cryptography – from the Greek word for ‘hidden secret’ – is the use of techniques for secure communication in the presence of third parties. These third parties are called adversaries. Cryptography is about constructing and analysing protocols that overcome the influence of these adversaries – and is used in information security, data confidentiality, data integrity and so on. Modern cryptography uses mathematics, computer science and electrical engineering. Applications include ATM cards, computer passwords and electronic commerce.
A credit card with smart-card capabilities. The 3-by5 mm chip embedded in the card is shown, enlarged. Smart cards combine low cost and portability with the power to compute cryptographic algorithms. Image: Wikimedia Commons
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ost mathematical research is published in academic journals or discussed at conferences, but some of the mathematicians who work in the area of cryptography realise that the rules are different for them. If they discover a new code or crack an existing code, then national security concerns might mean that their work is kept secret for years or decades. For example, the Bletchley Park codebreakers had to wait until the 1970s before their contribution to the war effort was declassified, by which time many of the leading figures had already died. Alan Turing, perhaps the most famous Bletchley codebreaker, tragically committed suicide in 1954, having received no public recognition for his contribution to breaking the German Enigma code. As 2012 is the centenary of his birth, many mathematicians and historians hope that this will be an opportunity to remember his genius and the extraordinary efforts of his Bletchley colleagues. Although modern encryption is a more public affair, because of its relevance to the general public and businesses, there is still a large amount of clandestine cryptography, and there are cryptographers whose brilliance continues to be shrouded in government secrecy. Indeed, while writing The Code Book, I discovered that a vital cryptographic invention, something that many of us use every day, has its own secret history. The invention is something called public key cryptography (PKC),
which is vital to how we exchange data in the information age. Without PKC, everything from e-commerce to secure phone calls would not be possible. First, I will explain why PKC is necessary, then I will explain how it works, then who discovered it, and then who really discovered it. Why is PKC vital in the information age? Let’s meet three characters who often crop in discussions about cryptography, Alice, Bob and Eve. Typically, Alice wants to send a secret message to Bob, but Eve (the eavesdropper) is trying to intercept the message. Naturally Alice wants to protect the message, so she encrypts or scrambles it. In order for this to work, however, Bob has to be able to unscramble the message, which means that he needs to know the recipe that Alice used to scramble the message in the first place. Alice has to somehow get the scrambling recipe, known as the key, to Bob without it falling into the hands of Eve. Essentially, the only solution for Alice is to send the key to Bob via a trusted courier beforehand. This so-called key distribution has been at the heart of cryptography for millennia. The officials who ran the German Enigma network would distribute keys, and in the 1970s banks employed specially vetted dispatch riders, who would race across the country with padlocked briefcases, personally distributing keys to everyone that the bank would communicate with over the next week. Similarly, government security agencies
or why you can buy things online Alice Bob's public key
751A696C 24D97009 Alice and Bob's shared secret
Alice's private key
Bob Alice's public key
Bob's private key An aerial photograph of the Government Communications Headquarters (GCHQ) in Cheltenham, Gloucestershire, UK – called ‘the doughnut’. Image: Wikimedia Commons
would transport tons of keys around the world every day. When ships carrying key material came into dock, cryptocustodians would march on board, collect stacks of cards, paper tapes, floppy disks, or whatever other medium the keys might be stored on, and then deliver them to the intended recipient. Key distribution might seem like a mundane issue, but it was the weakest link in the chain of security, because there was always the risk of a courier selling keys to the enemy. Also, as communication networks grew in size, the problem also grew, and it became clear that key distribution was turning into a logistical nightmare. However, finding a solution seemed to be impossible. If Alice wants to share a secret message with Bob, then surely she must first agree another secret with him, namely the key? Common sense seems to suggest that key distribution is an annoyingly necessary part of secure communication, but PKC demonstrates that there is a way around the problem.
Who discovered PKC? The solution to the key-distribution problem has a certain ‘make-youkick-yourself’ quality. What seemed impossible for thousands of years suddenly seems possible. The first people to announce that they had developed theoretical and then a practical approach to PKC were Whitfield Diffie and Martin Hellman at
751A696C 24D97009 Alice and Bob's shared secret
In the Diffie-Hellman key exchange scheme, each party generates a public/private key pair and distributes the public key. After obtaining an authentic copy of each other’s public key, Alice and Bob can compute a shared secret offline. The shared secret can be used, for instance, as the key for a symmetric cipher. Image: Wikimedia Commons
A diagram to show how Alice and Bob use public key cryptography. Image: Wikimedia Commons
Stanford University, and Ronald Rivest, Adi Shamir and Leonard Adleman at Massachusetts Institute of Technology (MIT). When they published their research over the course of a few years in the mid-1970s, they soon became cryptographic superstars. They had made one of the greatest contributions in the history of cryptography. I have only described PKC in terms of an analogy with padlocks, and the real challenge for Diffie, Hellman, Rivest, Shamir and Adleman was to transform the padlock analogy into something mathematical that could be implemented on a computer and sent down a wire. They had to invent a mathematical padlock, something that involved a public formula that Alice could apply to scramble a message, but something that only Bob could unscramble because he
How does PKC work? Let’s return to Alice, Bob and Eve and let’s imagine encryption in terms of locking a message inside a box. Alice puts her message in a box, puts a padlock on the box, and then sends it to Bob. The good news is that the padlock stops Eve reading the message, as she does not have a key. Unfortunately, it also stops Bob accessing the message … unless he has a copy of Alice’s key. In
other words, we have run into the keydistribution problem again. Alice cannot securely send Bob a message unless she has already sent him the key. However, there is a sneaky solution to this problem, which avoids distributing any keys. Let’s turn the problem on its head, and let’s allow the receiver, not the sender, to take more responsibility for encryption. Imagine that Bob designs a padlock and a key. Although Bob would make only one copy of the key, which he would keep with him at all times, he would manufacture hundreds of padlocks, and distribute them to post offices all over the world. Then, if Alice wants to send a message to Bob, she would simply go to her local post office, ask for one of Bob’s padlocks, then put the message in a box and finally lock it using Bob’s padlock. The nature of padlocks is such that Alice (or anybody else) can easily lock Bob’s padlock shut, but only Bob has the key required to open the padlock. The key never leaves Bob, and so the key-distribution problem no longer exists.
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FactFile Q RSA Data Security Inc. In April 1977 three MIT scientists started the process of building an asymmetric cypher that would revolutionise the world of secure information transfer. Ron Rivest, Leonard Adleman and Adi Shamir were a ‘perfect team’. Rivest and Shamir are computer scientists and Adleman is a mathematician. This is what is needed to build an asymmetric cipher: 1. Alice must create a public key. She then publishes this so that Bob (and everyone else) can use it to encrypt messages to her. Because the public key is a one-way function, it must be virtually impossible for anyone to reverse it and decrypt Alice’s messages. 2. However, Alice needs to decrypt the messages that are being sent to her. She must therefore have a private key, some special piece of information, which allows her to reverse the effect of the public key. Therefore Alice – and only Alice – has the power to decrypt any messages sent to her. At the heart of Rivest’s asymmetric cipher is a one-way function based on the sort of module functions described in the article on public key cryptography. What Alice does is choose a personal value of N. This allows her to personalise her one-way function. So to choose N, Alice picks two prime numbers p and q and multiplies them together. A prime number is a number that can only be divided by one and itself. Alice could chose two small prime numbers such as 7 and 13, but these are too small – it would be too easy for someone to do a relatively small number of calculations to find Alice’s value of N. So Alice chooses: p = 17 159 q = 10 247. This gives a value of 175 828 273 = N. This is Alice’s public encryption key. She
could print it on her business card, publish it on her Facebook page – anywhere in fact. If Bob wants to encrypt a message to Alice, he looks up Alice’s value of N (175 828 273) and then inserts it into the general form of the one-way function. To encrypt a message he now takes Alice’s one-way function, inserts the message, notes down the result and sends it to Alice. This message is secure – no-one can decipher it. To decrypt the message, Alice needs a way to reverse the one-way function. How can she do this? This is where Rivest comes in. He designed a one-way function so that it is reversible to someone who knows the values of p and q, the two prime numbers that are multiplied together to give N. Alice may have told everyone that her value for N is 175 828 273, but no-one knows her values for p and q, so only she has the special information that is needed to decrypt her own message. But, wait a minute, if everyone knows N, then surely people can quickly deduce p and q? However, it turns out that if N is large enough, it is virtually impossible to deduce p and q from N. The elegance – good mathematical term – of this is that you can multiply prime numbers together quickly and easily, for example 9 419 multiplied by 1 933 gives us 18 206 927. But if you were given the number 18 206 927 and asked to find the prime factors (numbers that were multiplied to give 18 206 927) this would take much longer. The secret is to use very, very large prime numbers, for example a prime as big as 1065 – this means 1 followed by 65 zeros. This would have given a value of N that would have been roughly 1065 x 1065 which is 10130. Security expert Simson Garfinkel estimated that a 100 MHz Intel Pentium computer with 8 MB of RAM would take roughly 50 years to factor a number as large as 10130. However, even with this size
had the mathematical key. There are various websites that describe the mathematics of PKC, such as: http://nrich.maths.org/2200 Who really discovered PKC? Without wanting to undermine the brilliant work of the US-based researchers usually associated with the discovery of PKC, I want go back to the real origins of this form of encryption at the Government Communications Headquarters (GCHQ) in Britain. The true father of PKC was James Ellis, a brilliant, unpredictable and introverted cryptographer. His colleague Richard Walton recalls: ‘He was a rather quirky worker, and he didn’t really fit into the day-to-day business of CESG. But in terms of coming up with new ideas he was quite exceptional. You had to sort through some rubbish sometimes, but he was very innovative and always willing to challenge the orthodoxy. We would be in real trouble if everyone in GCHQ
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Finding prime numbers using prime rectangles: The number 12 is not a prime, as 12 items can be placed into three equal-size columns of four each (among other ways). 11 items cannot be all placed into several equal-size columns of more than one item each – there will always be some extra items left (a remainder). Therefore the number 11 is a prime.
RSA secure ID security tokens.
Image: Wikimedia commons
of prime number, if enough computers worked together, the code could be cracked. It is now generally accepted that N needs to be at least 10 308. The combined efforts of one hundred million personal computers would take more than 1 000 years to crack such a cipher. With sufficiently large values of p and q, RSA is impregnable. But, it might happen one day ... Based on The Code Book: The secret history of codes and code breaking by Simon Singh.
was like him, but equally we need some people with his flair and originality’. Fully aware of the problems of key distribution, Ellis was the first to develop a theoretical form of PKC, but neither he, nor anyone else at GCHQ, could provide the necessary mathematics. Three years later, however, a pair of Cambridge graduates, Clifford Cocks and Malcolm Williamson, joined GCHQ and invented two separate techniques for implementing Ellis’s idea. Together, Ellis, Cocks and Williamson had made the greatest breakthrough in twentieth century cryptography, but they could tell nobody about they had done. PCK was classified top secret. Even though PKC was invented independently in America, then commercialised and made public, GCHQ remained silent about its own work throughout the 1980s and much of the 1990s. It was not until the summer of 1997 that GCHQ eventually decided that the true history of the invention
of PKC would be explained at a major conference in December. Sadly, James Ellis, aged 73, died just a month before the world learnt of his great contribution to the information age. In 1987, Ellis wrote an internal GCHQ memorandum. It includes his thoughts on the secrecy that so often surrounds cryptographic work: ‘Cryptography is a most unusual science. Most professional scientists aim to be the first to publish their work, because it is through dissemination that the work realises its value. In contrast, the fullest value of cryptography is realised by minimising the information available to potential adversaries. Revelation of secrets is normally only sanctioned in the interests of historical accuracy after it has been demonstrated that no further benefit can be obtained from continued secrecy.’ ❑ Simon Singh (www.simonsingh.net) is a science writer and the author of The Code Book and Fermat’s Last Theorem.
How smart is a smartphone? Why are smartphones called ‘smart’? Are they smarter than people? Are they just called ‘smart’ so we will buy them? Do we even need ‘smart’ phones? Gary Marsden takes a look.
n this article we want to take a look at why smartphones are so popular and figure out just how ‘smart’ they are. I can hear you! – fundamental science. We have become so fascinated by what smartphones can do (games, Facebook, Twitter, etc.) that we can easily forget the reason that they were created in the first place – so that we can make calls from anywhere on the planet to anywhere else on the planet. So the first way in which smartphones are smarter than us is that they can hear things that we cannot. Cellphone signals are broadcast as electromagnetic waves through the atmosphere. These waves have a frequency of 380 - 1 900 MHz. In other words, they can detect waves that vibrate up to 1 900 000 000 times per second! As humans, we use our ears to hear sound waves transmitted in air at a frequency of 20 - 20 000 vibrations per second. Of course, because a
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smartphone has a microphone, it can also detect audio waves in the same frequency as the human ear. And, because it has a speaker, it can reproduce those sounds with a greater range than human vocal cords. Humans are also beaten by smartphones when it comes to seeing! Most phones now have high-resolution digital cameras which can see light as humans do. This light is what we call the visible spectrum – the colours of the rainbow which fall between 400 (red) and 790 (violet) THz. However, smartphone cameras can see light that falls below 400 THz – infra-red. You can check this yourself using a television remote control. The remote control uses infra-red light to send control messages to the television. Our eyes cannot see this, but if you look at the remote with the camera on the smartphone, you will see it glow every time you press a button. The smartphone transforms the (infra-red) light we cannot see into light that we can.
Maths genius You may have noticed that most smartphones come with a calculator, and can perform basic mathematics. But that is just the beginning of the mathematics a smartphone can do. For example, in order for you to play 3D games, the phone must perform complex trigonometry and vector mathematics to draw the game environment and allow characters to walk around and obey the laws of physics to make the game as realistic as possible. In order to do this, current handsets can perform around 220 000 000 calculations every second (in computer speak this is known as 220 MFlops – 220 million floating point operations per second). This is similar to a desktop computer from eight years ago. Not only can the phone create virtual worlds, but it is fitted with all sorts of sensors so that it knows where it is in the real world. Most smartphones come with a GPS receiver, which detects positioning satellites overhead, allowing the
This photograph shows how a smartphone can ‘see’ a television remote. Image: www.indestructables.com
Cellphone signals are broadcast as electromagnetic waves.
phone to know, with an accuracy of 10 metres, any location on the planet. This is coupled to another sensor, called a magnetometer, which allows it to detect the Earth’s magnetic field, much like a compass. This allows the handset to know which direction it is facing so it can tell users where they are and how they can get to the places they want to go to. Besides knowing where on the planet they are, and which way they are facing, smartphones have two other sensors to help them learn about their physical orientation. The first of these is a gyroscope – a miniature version of regular gyroscopes that you spin using a length of string. Having a gyroscope inside allows the phone to know what angle it is being tilted at and how far from level it currently is. Changes in location are measured by the second sensor, an accelerometer, which detects how quickly a handset is moved and in what direction. It is these sensors that allow you to control games on the smartphone, simply by moving and tilting the device. Are smartphones too smart? Smartphones are able to see, hear and sense their environment better than humans can. They can do complex mathematics faster than us and have
perfect memories, capable of storing thousands of songs without forgetting a single note. But they are not smart. Smartphones, and digital technology as a whole are so popular because they allow humans to be smarter. By storing information perfectly, allowing us to communicate whatever we want (images, emails, tweets) wherever we want with almost anyone (South Africa has more active SIM cards than it has people), the smartphone is a platform that allows us to do what we do best as humans. For example, some of the projects that my students and I am working on are allowing people who cannot read and write to share their knowledge and information. By utilising the camera and microphone on a smartphone, we allow illiterate people to record ‘digital stories’ – a collection of images with a voice-over – which they can then share with other people. The image in column three shows the app we built. It has no text on the interface, as the people who use it cannot read. This is just one app that has been created specifically for Africa. There are many others that help people with their education, their health, their finances and their entertainment. We are really just starting to scratch the surface.
An app that allows people to send images and voice messages over a smartphone. Image: UCT Department of Computing
This is just the beginning Smartphones are technically amazing devices. They are built using amazing science and technology but, ultimately, the critical thing is that they allow us humans to be smarter. In places like Africa with few computers, smartphones can reach and improve the lives of many people who have, until now, been unable to benefit from digital technology and communication. Through research we can make a smart planet using smartphones. ❑ Gary Marsden is a professor in the Computer Science Department at the University of Cape Town. His research interests are in Mobile Interaction Design and ICT for Development. He has co-authored a book, with Matt Jones titled Mobile Interaction Design published in 2006. He is currently director of the UCT ICT4D Research Centre and the UCT-Hasso Plattner Research School. He won the 2007 ACM SIGCHI Social Responsiveness award for his research into using mobile technology in the developing world. Despite all of this, he still cannot use all the features on his mobile phone.
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A breakthrough for HIV research South African scientists find unique changes in the virus of two women infected with HIV that may change the way we tackle the disease. Quest looks further.
group of scientists from a number of different research centres in South Africa has found changes in the virus of two women infected with HIV that allowed the women to produce potent antibodies that can kill up to 88% of HIV types found around the world. An HIV vaccine The significance of this research lies in its importance for the development of an HIV vaccine, one of the most important and ambitious goals of HIV research. An effective vaccine against HIV and AIDS would provide a powerful tool to influence the course of the HIV pandemic. Despite significant advances in HIV vaccine research, to date no effective vaccine has been developed. How does this new research help us towards the search for a vaccine? The antibodies that these two women produce are able to kill (neutralise)
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up to 88% of HIV types – and not just local types of the virus, but types found around the world. This means that the antibodies are what is called ‘broadly neutralising’, something that is extremely important for the potential development of a vaccine. Because there are so many sub-types of HIV, it is important that any vaccine that is developed contains antibodies that are effective against as many of these sub-types as possible. One of the challenges in HIV vaccine research has been the inability to stimulate antibody responses, and the stimulation of a neutralising antibody response is the main endpoint of a vaccination. In HIV vaccine research, this has been particularly difficult to do. HIV is highly diverse genetically. Epitopes on antibodies to HIV are masked by a shield of carbohydrate and the form of HIV is very flexible. All this has made it difficult to produce a vaccine
that recognises – and can neutralise – antibodies to the virus. How did researchers come across these two women? This breakthrough occured when researchers followed-up two HIVinfected women who had been part of trials on an HIV-neutralising vaginal gel. The scientists found that the evolution of the HI virus shapes the types of antibodies that are produced over time. These broadly neutralising antibodies are able to recognise, target and bind themselves to the small pieces of sugar-coated protein on the virus and then block it from infecting healthy cells in the body. When scientists traced back the evolution of the virus, they found that the HI virus that caused infection in many cases did not have this antibody target on its outer coating. But, over time, the body’s immune reaction that produces antibodies placed selection
The course of HIV infection
What is an antibody?
HIV damages the immune system over time.
An antibody is a large Y-shaped protein that is produced by B-cells in the immune system. Antibodies are used by the immune system to identify and neutralise foreign objects such as bacteria and viruses. The antibody recognises a unique part of the foreign object, called an antigen. At the top of the Y of an antibody there is a structure that is like a lock and which is specific for one particular ‘key’ – called an epitope. When an antibody binds to antigens on a foreign object, this can prevent a virus or bacteria, for example, from damaging the cells of the organism that is being attacked by the foreign object.
The relationship between the viral load and the CD4+ lymphocyte count. Image: Wikimedia Commons
Everyone produces antibodies to the virus, but the virus eventually overwhelms the body’s immune system, leading to the so-called opportunistic diseases, such as tuberculosis, which lead to AIDS and death, without antiretroviral treatment. Scientists have known for some time that there are different disease profiles in HIV infection.
Rapid progressors A small proportion of individuals develop AIDS within one to two years of infection. In these people the virus multiplies rapidly and there is a very sharp drop in the levels of CD4+ cells. As a result, these people cannot mount an immune response and are not able to control replication of the HI virus.
Intermediate progressors Most people who are infected with HIV are able to regulate viral replication for many years because of an effective immune response. However, over time, there is a steady decline in the numbers of CD4+ cells and the immune system is eventually destroyed.
Slow progressors or long-term non-progressors A small proportion of individuals are able to control HIV viral load very effectively without antiretroviral therapy. Long-term non-progressors have low, and in many cases undetectable, viral loads with high CD4+ counts and healthy immune systems. Many of these people have been infected for more than 20 years and remain healthy. There seem to be many reasons for slow disease progression: n genetic factors n factors associated with the virus, such as infection with defective viruses n immunological factors, such as strong immune responses, including neutralising antibodies.
pressure on the virus to cover itself with a sugar – called a glycan. This created a point of vulnerability and allowed the broadly neutralising antibody to bring the virus under control. These types of antibodies are essential for an effective vaccine. However, they are rare, eventually developing in only around one-fifth of HIV-infected people. It is through understanding how these types of antibodies develop that a vaccine against HIV may one day be produced. Acknowledgements The study was conducted by a consortium of South Africa’s leading laboratory researchers in
AIDS that includes CAPRISA, the National Institute for Communicable Diseases (NICD) in Johannesburg, the University of KwaZulu-Natal, University of Cape Town, with partners from the University of North Carolina and Harvard University in the USA. The research was led by Dr Penny Moore, a Virologist from the National Institute for Communicable Diseases of the National Health Laboratory Services. Over a period of five years, the researchers have been studying how some HIV-infected people develop broadly neutralising antibodies because they kill a wide range of HIV types from different parts of the world.
Each antibody binds to a specific antigen – an interaction similar to a lock and key. Image: Wikimedia Commons Antibodies are secreted by a type of white blood cells called plasma cells. The general structure of all antibodies is very similar, but the small region at the tip of the protein is extremely variable, allowing millions of antibodies with slightly different tip structures, or antigen binding sites, to exist.
This research was funded by the South African government’s Department of Science and Technology (through its Technology Innovation Agency), the US National Institutes for Health (through the NIAID-funded Centre for HIV/AIDS Vaccine Immunology) and the Bill & Melinda Gates Foundation (through its Collaboration for AIDS Vaccine Discovery). The long-term follow-up studies of the women in KwaZuluNatal were additionally funded by USAID (through CONRAD) and CDC as part of PEPfAR. Fellowships from the Fogarty International Center and the Wellcome Trust played a key role in enabling this research. ❑
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The full glory of a humpback whale’s tail.
Conserving marine life in Mozambique bique. Zavora Lodge, Mozam
Androniki Pouris on humpback whales, manta rays and nudibranchs at Zavora Marine Laboratory, Mozambique.
A Sunset at Zavora.
Andronikie Pouris and Jessica Bergman snorkelling.
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whole month on the sea and by the sea – this is what an internship at the Association of Coastal Conservation of Mozambique (ACCM – Zavora Marine Lab)/Iemanja Research and Conservation Projects, Mozambique means. A whole month of combining diving, my favourite hobby, and studying marine creatures, my future study area – this was a combination of the best things in the world. I left a cold OR Tambo International Airport and arrived in a very hot Inhambane, Mozambique after a short trip. Another intern, Jessica Bergman, had a much longer flight from California, USA. Once we arrived in Inhambane, Zavora was another two hours’ drive – as remote as we were told it would be. The researchers at the Marine Lab showed us around and the next day we set out to work – and they mean work. We suffered from information overload but it was all interesting and every day brought a new adventure. When we were not diving, we were snorkelling. Every second day was
spent whale watching. The rest of the time we dived at different reefs, to different depths to find nudibranchs and manta rays and collect data, or went to sea to collect data on humpback whales. The area around Zavora is wild and beautiful – a truly African experience. Mantas The largest types of manta species in the world are the reef manta ray (Manta alfredi) and the giant manta ray (Manta birostris). Mantas have triangular wings and paddle-lobes that extend in front of their mouths. Their wing span can be up to 7 m, and they can weigh up to 1 300 kg. Manta rays are generally found in tropical and subtropical waters. They are commonly seen at cleaning stations, which are areas of the reef where fish such as wrasse, remora and angel fish ‘clean’ the matas, eating parasites and dead tissue on the rays. Mantas are filter feeders, eating plankton and fish larvae. They can consume 20 – 30 kg of plankton a day.
A manata with its mouth open.
The author diving with a manta.
Image: Yara Tibirica
tail. line wrapped around its A manta ray with fishing
The gender of the mantas is determined by the length of the pelvic fins in the genital area – females have two pelvic fins that conform to the contour of their body, while the males have two pelvic fins that look different from those of the females. Males also have two claspers, which grow longer than the pelvic fins. In August we saw and identified four giant mantas and 27 reef mantas, all with wing spans in Local fishermen with a the region of 3 - 4 m. They are manta that they had cau ght. spectacular creatures with unique ▲ ▲
At Zavora there are two main cleaning stations – Witches Hat Reef and Vasco’s Reef. Both reefs are 5 km away from the shore and are 12 – 20 m deep. Manta rays are also seen at Great Wall Zavora which is 10 km from shore and 27 m deep. We had to identify the mantas we saw when we dived. Reef mantas have patterns/spots/grey area on their belly and between the gills. Giant mantas do not have these features. Each manta is unique – the patterns can be used in the same way as fingerprints.
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Halgerda wasiniensis Chromodoris quadricolo r
Nudibranchs Yara Tibirica (the coordinator of the Zavora Lab internship) is studying the taxonomy of nudibranchs. She writes: ‘About three years ago I moved to Zavora to start a research programme mainly focused on manta rays. Soon other creatures also got my attention. I fell deeply in love with the [sea] slugs and I started a new research project looking at the distribution and diversity of sea slugs in Zavora. Much smaller than manta rays but equally interesting, sea slugs are full of mysteries and undiscovered facts. As a group they have some of the biggest diversity of behaviour, feeding and survival strategies. You can imagine that being a soft-bodied slug in a sea full of predators would not be easy if they hadn’t developed the most amazing and complex ways to protect themselves. These animals are a strange combination of chemical industries with the butterflies’ beauty. At global level their biology and ecology are poorly understood, with many species still being discovered every year. In Mozambique they have never been studied before so almost every day of field work we find exciting new information. One of my favourite parts of the day is spending an hour or so with the head down and fins up moving like plankton looking for the colourful and extraordinary sea slugs. There is currently a huge scientific discussion about the evolutionary nature of sea slugs and their taxonomy is changing, but while it is not yet defined we use the old classification, grouping them as opisthobranches. The most famous opisthobranches are the nudibranchs, which are also the largest group. Looking for nudibranchs while you are diving in Zavora is almost like looking for birds in Kruger National Park. There are all these impressive big animals which are hard to take your eyes off but if you can do so, you might discover a completely new world often ignored by most people. Under the magnificent lens of the microscope, the details highlight the perfection of these creatures and unexpected things are observed. One day I saw a worm coming out of the nudibranch Glossodoris’ anus, how amazing was that! Over two hundred species of opisthobranches have been found during
behaviour. Mantas are very confiding creatures. Sometimes they came swimming right up to us and got so close that you could almost touch them. Mantas are vulnerable to fishing – not just to being caught, but to becoming entangled in fishing line. We saw one manta with fishing line wrapped around its tail and body. We managed to cut one part of the line, but each time we tugged on the line and freed it, the manta would swim off. But, the ray seemed to realise that we were trying to help it and it swam backwards and forewards to us until we had managed to get all the line off. It was a wonderful feeling to free this beautiful creature.
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our study in Zavora and we are still finding more and more. Most of them are new recordings for the country and around thirty of them described species for science. In order to correctly identify the species and further describe them, it is Nembrotha aurea necessary to look at both the external and internal morphology, as well the radula, a kind of slug “tongue”. Radulas contain tiny teeth in different numbers and shapes that are unique to the species depending on what the species feed on, just like sharks. The correct identification of species is crucial to understand their ecology; therefore our project is focused on both the taxonomy and the ecology. Most studies to date are done by scientists who do not live in the field and only go for expeditions from time to time to collect material. At Zavora Marine Lab we are lucky enough to live and work in our study area. Although living in such a remote place makes it harder to do part of the taxonomy analyses, it facilitates better understanding of the ecology of the group. Through a combination of underwater techniques such as quadrat, roving diver, substrate analyses and traps we are able to find out a lot of new information such as feeding and mating behaviour and population flux. Our continuous discovery of new species and facts about the sea slugs shows how little we know about marine life and how limited our capacity is to see what is just in front of our eyes. On one hand it fascinates me but on the other, it worries me that much of this natural beauty will be lost before we get to know it as the pressure on the ocean increases every single day.’
Unfortunately, the needs of local people and the conservation of the mantas come into conflict on occasion and I saw a manta caught and cut up by local fishermen. This is a great loss to the manta population as they only breed every two to three years. Humpback whales Humpback whales (Megaptera novaeangliea) is a species of baleen whales. Baleen whales are characterised by their baleen plates (filter-feeding system) that filter their food from water. They do not have teeth. They can grow up to 12 - 15 m and weigh anything from 25 to 40 tons when they are adults. When the young are born they are 4 - 4.5m in length and
weigh 1 - 2 tonnes. The gestation period is 11.5 months and a mature female humpback whale can only have one calf every second or third year. The whales’ average age is 48 years but they can live up to 100 years. They feed on krill (small shrimp-like crustaceans) almost exclusively, but some humpbacks also feed on small schooling fish. When they feed, they swim in groups using a bubble net – they blow bubbles in a circle, which creates a cylinder-like hole in the water that traps their prey in the middle. In time the bubble circle starts to shrink and eventually a group (with one leader giving the signal) all come up with their mouths open and filter the krill or small fish into their mouths.
We were at Zavora during the breeding season. Mothers and calves swim together so that the mothers can protect their calves from killer whales, the species’ main enemy. We monitored the number of whales we saw, their group size, whether they had calves, what behaviour they were displaying and where they were going. Our team took a 12-hour shift every second day. When these magnificent whales jump out of the water it is called breaching. We often saw a mother do something and the calf copying the behaviours. We also went on ocean safaris with the Mozdivers (the only dive school in Zavora). When we were at sea we recorded the GPS coordinates when we saw whales, how many were in the group and if they had calves. We followed them till they dived or until we found another group. We tried to take photos of the underside of the tail (fluke), so that we could identify individual whales. Each whale has a different pattern on its fluke, much like a human finger print. Back in the lab we uploaded the pictures to a database so that when a whale is spotted elsewhere, it can be identified and its pattern of movement can be recorded. Everyone can participate in this project. Just take a picture (pictures must be taken in Mozambique) of the under part of the fluke, and e-mail it to info@zavoralab. com and the photo will be uploaded to the database and website www.mozwhales.org. The experience This was an amazing month of diving and photographing, but most of all
learning about, marine life in the Indian Ocean. A team of vibrant young women with a particular interest in marine life and all its wonders showed me how to enjoy these animals and how marine research is done. No matter how difficult ck whale. it was to help a manta, or First sight of a humpba to see one being killed, or how wonderful it was to see the humpback whales and enjoy the colours and shapes of the nudibranchs, this was a lifetime experience that is worth remembering for ever. Thank you team for a wonderful life experience. ❑ (All photographs by Androniki Pouris except where otherwise stated.) Androniki Pouris was born on 21 November 1989 in Pretoria, attended Lynnwood Ridge Primary School, and matriculated at St Mary’s DSG in 2007. She is currently studying for her BTec at TUT (Tshwane University of Technology). She’s an avid photographer and is qualified as a PADI Scuba Diver Instructor and a Scientific Diver. She had her first scientific scuba diving experience, utilising her photography skills at Zavora Marine Lab in Mozambique in August 2012.
The different categories of humpback whale tails.
The team (from left to right): Emma Hayes, Yar a Tibirica, Comex (the dog), Sabrina , Jessica Bergman, Andro niki Pou
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Hydrogen fuel cells: for electricity and transport The energy released by hydrogen fuel cells has many uses – among them electricity and transport. Jan Smit continues the story of hydrogen’s use in renewable energy.
The motor bike that runs using the energy from a hydrogen fuel cell that was developed at the Tshwane University of Technology. Image: Tshwane University of Technology
Jules Verne, who wrote science fiction novels in the 19th century and predicted much of today’s technology. Image: Wikimedia commons
‘I believe that water will one day be employed as fuel, that hydrogen and oxygen will constitute it, used singly or together, and will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable.’ Jules Verne, The Mysterious Island (1874)
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Honda’s FCX Concept vehicle. (The Clarity succeeded the Concept model.) Image: http://automobiles.honda.com/fcx-clarity/
The diminishing role of fossil fuels The role of fossil fuels as the major suppliers of energy on a large scale will inevitably decline in the future, because: n Sources of fossil fuel will be used up and prices will rise as a consequence. When this will eventually happen is hard to predict. All that is certain is that it will happen. n Fossil fuels contribute to global carbon dioxide pollution. Global pollution causes global warming, which we know will be disastrous to humans, other animals and plants. As a result scientists and technologists are seriously exploring alternative energy sources, sources that have the potential to supply clean energy on a large scale. Candidates include nuclear, wind, solar energy, the power of the sea’s tides, water and hydrogen. Hydrogen is already used on a small scale in internal combustion engines, for example in motor cars. In 2010 a bike powered by a hydrogen fuel cell was demonstrated in South Africa. This was developed by engineers at the Tshwane University of Technology in Pretoria. This article focuses on electrical energy generation by hydrogen fuel cells.
The first hydrogen fuel cell was put together in 1839 by Sir William Robert Gove, a Welsh judge, inventor and physicist. He mixed hydrogen and oxygen in the presence of an electrolyte and produced electricity and water. The term fuel cell was used many years later (1889) by Ludwig Mond and Charles Langer. In 1932 Francis T Bacon, a direct descendant of the famous British philosopher, scientist, statesman, jurist and author Francis Bacon, demonstrated a five-kilowatt fuel cell (the Bacon cell) that could power a welding machine. In October 1959 Harry Karl Ihrig, from the Allis-Chalmers tractor manufacturing company, demonstrated a 20-horsepower (about 14-kilowatt) tractor. This was the first ever vehicle powered by a fuel cell. General Electric produced the fuel cell-based electrical power system for NASA’s Gemini and Apollo space capsules in the early 1960s. The principles of the Bacon cell were used as basis for the design. Today the space shuttle’s electricity and water are provided by fuel cells. NASA has funded more than 200 research projects on fuel cell technology. It is as a direct result of this research that fuel cell technology can now be used by the private sector. The first passenger bus powered by a fuel cell was completed in 1993. Several fuel cell cars are being built in Europe and the USA. Toyota and Daimler Benz launched prototype fuel cell-powered
Q Renewable energy Right: A hydrogen fuel cell powered by a solar panel. Image: Science for Africa, October 2006 (Peter Horzovski)
cars in 1997. In the USA private persons can lease hydrogen fuel cell powered Hondas at several sites. Hydrogen fuel cells are the subject of research across the world. The emphasis is on improving the effectiveness, cost, lifetimes and output of these cells. There are several such projects in South Africa at present. One is at the North West University NWU), Potchefstroom campus. This comprehensive research project ranges in scope from the basic science of fuel cells to their practical applications.
excellent when compared with 58% – the maximum efficiency of an internal combustion engine. A challenge that research is facing is the production and storage of hydrogen. Scientists at North West University are constructing a plant to produce hydrogen from water. Solar panels on the roof of a car shade on campus will supply electric current to an electrolyser where water is dissociated into oxygen and hydrogen. The same PEM used in the hydrogen fuel cell to produce an electric current can be used to produce hydrogen. The research on hydrogen production and storage at NWU is being led by the international expert, Dr Dmitri Bessarabov, who was recruited from Canada under the DST programme on hydrogen and fuel cells. How can a PEM be used to produce hydrogen from water? Water is fed into the cell at one side of the PEM (on the right in the diagram). The solar cell connected to the cell provides energy to pull the hydrogen and oxygen atoms of an H2O molecule apart. The hydrogen ions (protons) go through the PEM where they pick up electrons to form hydrogen gas. The oxygen molecules are released at the cathode and can be stored or released into the air. The hydrogen gas is usually stored in a vessel and then used in a fuel cell to produce an electric current, water and heat. Storing hydrogen gas
A hydrogen fuel cell producing an electric current. Image: Based on Science for Africa. October 2006 (Peter Horszovski)
has advantages over solar energy. Solar panels only operate in sunshine and the solar-generated electrical energy must be stored in either heavy expensive batteries or as hydrogen gas. The electrolyser is able to compress hydrogen to a pressure of about ▲ ▲
How does a hydrogen fuel cell produce electric current? A hydrogen fuel cell is a simple device. It consists of a few solid parts, shown in the diagram. There is a thin membrane in the middle of this rectangular device (yellow in the picture), called the proton exchange membrane (PEM). The anode is on the one side of the membrane. This is where electrocatalytic oxidation of hydrogen takes place. The cathode is on the other side. This is where oxygen reduction reactions (ORR) take place. Hydrogen gas is fed into the cell at the anode side. In the membrane electrons are stripped from the protons (remember that a hydrogen atom is just one proton and one electron). The proton goes through the membrane to combine with oxygen, usually from the air, to form water and heat. The electrons stripped from the hydrogen atoms make up an electric current in the external circuit. These electrons find their way to the cathode through the external circuit. In the external circuit the electrons do work: they can power a bulb, drive a motor or any electrical appliance. At the cathode the electrons combine again with the hydrogen ions (protons) to form hydrogen atoms and these atoms combine again with oxygen in the air to form water. A catalyst is needed for this process. Platinum is commonly used, but other catalysts for example, nickel, can also be used. Catalyst research is one of the projects at NWU. A key element in a fuel cell is the proton exchange membrane and several types have been developed. The efficiency of a hydrogen fuel cell is relatively high. Its highest theoretical efficiency can be up to 83%. This is
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20 bars. This is still small if you consider the mass of hydrogen that can be stored in, for example, a cubic meter at that pressure. There is ongoing research into how to compress the hydrogen further. The main problems related to the production of hydrogen by solar cells are: n The electric current generated by the solar cells is not constant. In the morning and evening the Sun’s light intensity is low and so there is less electric current from the solar cells. At night and on rainy or cloudy days the electric current is zero. The solar panels should be large enough to generate sufficient hydrogen to be stored for such times. n Salts and chemicals dissolved in tap water will contaminate the electrolyser, so solar distillation may be needed to produce distilled water. The main advantages of generating electricity using hydrogen fuel cells are: n Research can improve on the technology. n The efficiency of electricity generation is already relatively high. n There is no pollution because only water, heat and electricity are produced. n It is a silent way of generating electricity. n The direct current (DC) generated can easily be converted to 220 V AC at 50 HZ, the grid voltage and frequency used in South Africa by ESKOM. n It is still costly, but the gap between ESKOM’s tariffs and fuel cellgenerated electricity is narrowing. Recently (October 2012) Eskom proposed annual increases of 16%. In practice the implication is that in about five years ESKOM’s tariffs would more than double. The everincreasing price of petrol and diesel for transport would soon mean that the cost of using hydrogen fuelled vehicles would be around the same as using petrol and diesel. There are two main ways in which hydrogen can be used instead of conventional energy: n The first is to provide electricity to relatively small users. For example, households, small businesses and cell phone towers may use hydrogen fuel cells to generate electricity. The fuel cells would be
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static, and locally placed to provide electricity directly to the user. n The second major application would be for transport, from simple motor bikes to large trucks and buses. Hydrogen-fuelled motor cars, trains, buses and boats would relieve the demand for fossil fuels like petrol and diesel. An additional benefit would be that the exhaust gases of these vehicles are pure water. Solar cells Solar cells are also a promising alternative renewable energy source. Solar energy is in abundance – at least in South Africa. If you cover the whole surface of the Earth with a layer of oil 1 m thick the energy contained in that oil would equal the energy produced by the Sun in one year (Carlo Rubia). When I measured the power of the Sun’s radiation at Potchefstroom in November at noon I found it to be 1.1 kW/m2. That is about the same as the heat produced by a stove plate. Problems associated with solar cells are: n The electricity cannot be stored directly. n Expensive heavy batteries with limited storage capacity are needed. However, as you have seen, the electric current can be used to produce hydrogen in an electrolyser, which can then be stored and used to generate electricity in a hydrogen fuel cell. Storing hydrogen Once produced, the hydrogen gas needs to be stored. Remember that hydrogen has the lowest density of all elements. There are several methods used to store hydrogen. One is to liquefy the gas. As it liquefies at the very low temperature of 33 K (-240 ºC) sophisticated machinery is needed. Thermal isolation is another challenge. Expensive well-isolated containers are needed. The hydrogen produced by the electrolysers at NWU reaches a maximum pressure of 20 bars without any additional compression. The solar electricity may be used to drive a compressor for further densification. Hydrogen can also be stored in ammonia (NH3). The ammonia is decomposed into hydrogen and nitrogen when the hydrogen is needed. The hydrogen used in cars is
currently stored in cylinders. These cylinders are heavy and the hydrogen is at high pressures, which can be hazardous. The cylinder may explode, in an accident for example, and there may be a fire. Remember that hydrogen is highly combustible and reacts violently with oxygen. The atmosphere contains about 20% oxygen. Leaking hydrogen in the inside of a car could explode if exposed to even a tiny electric spark. The future What is the future? Will hydrogen fuel cells provide inexpensive renewable energy on a large scale? Hopefully the fuel cell industry will follow the same road as the laser, but with a much shorter time scale between invention and wide-scale application. In 1924 Albert Einstein formulated the theory behind the use of lasers. But it was not until 1960 that Ted Maiman constructed the first optical laser. The first commercial lasers were soon on the market and were used mainly for scientific research. They were expensive and not easy to operate. Now lasers are inexpensive, easily available and are used in a wide range of applications. Will the hydrogen fuel cell develop the same way? This will require a change in our mindset and a move away from fossil fuels. ❑ Professor Jan Smit is Manager, Science Centre, NWU, Potchefstroom campus.
Acknowledgements The author wishes to acknowledge Mr. Frikkie van der Merwe, chemical engineer, Involved in research on hydrogen fuels cells and Dr Dmitri Bessarabov Director, DST Hydrogen Infrastructure Centre of Competence. SAASTA, NRF and DST provided financial assistance.
We create chemistry that makes compost love plastic.
Most plastics donâ€™t biodegrade, but ecovioÂŽ plastics from BASF disappear completely when composted in a controlled environment. Using compostable bags for collection of organic waste makes disposal more hygienic and convenient. Rather than ending up in landfills, the waste is turned into valuable compost. When the plastic bag you use today can mean a cleaner future for the environment, itâ€™s because at BASF, we create chemistry.
Inside the Pinnacle Point excavation with a yellow total station on the right Image: Erich Fisher
Early technology and human complexity Early modern humans on the southern African coast had the ability to produce small, portable and potentially lethal weapons far earlier than originally thought. Quest examines the latest research from Pinnacle Point.
Reproductions showing how the backed blades could be used on shafts of arrows or spear throwers. Image: Benjamin Schoville
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nce again, excavations at Pinnacle Point, on the southern Cape coast, have provided evidence of modern human behaviour arising far earlier than previously thought. The evidence that Kyle Brown, Curtis Marean and their team have unearthed shows that these early modern humans had the ability to develop advanced stone tools that have been dated to 71 000 years ago – this same technology becomes common elsewhere in Africa, Europe and Asia (Eurasia) about 20 000 years ago, and the earliest previous dates prior to the Pinnacle Point result were 65 000 years ago. The significance of this advanced technology is that it provides evidence of longstanding complex behaviour that may show that modern humans evolved in this coastal region of southern Africa and that this technology was important in their subsequent migration out of Africa.
Lethal stone tools and complex technology The technology in question is called microlithic technology. Microlith is the word used to describe small stone blades (bladelets) that are shaped into highly standardised shapes such as backed blades or segments. There is a specific technological definition of this process, ‘the process of manufacture (core reduction) is focused on the production of small flakes and bladelets less than 50 mm in maximum length’. Previous research has always placed microlithic technology in the Later Stone Age and Upper Palaeolithic phase, later than 45 thousand years ago in Africa and Eurasia. It was thought to be atypical for the Middle Stone Age in Africa (200 000 - 45 000 years ago) and not found at all in the Middle Palaeolithic in Eurasia. The technology is also thought to be a universal stage in the evolution of Palaeolithic technologies
treatment of silcrete. 4. Preparation of microblade cores on silcrete. 5. Controlled production of bladelets. 6. Reshaping of bladelets into microliths. 7. Production of mounts on wood or bone. 8. Adhesion of microliths to form compound tools.
– in other words, a stage that has to be gone through to get to the next level of technology. What the current research has found is the careful production of long, thin blades of stone that were then blunted – called backing – on one edge so that they could be glued into slots carved into wood or bone. This creates light weapons that can be used as either arrows in bows or as spear throwers (atlatls). The excavations at Pinnacle Point showed that the silcrete was heat treated. (See Quest 7(3) 2011. Using fire for more than light and warmth.) Remember that silcrete is a type of stone that is found mainly in Africa and Australia, which contains a high percentage of silica. Silcrete stone tools are common in coastal Middle Stone Age archaeological sites in southern Africa after about 70 000 years ago. The technological recipe for the production of microliths follows a long complex chain: 1. Collection of the silcrete at patchily distributed sources. 2. Collection and transport of appropriate wood for fuel to the places where the heat treatment took place. 3. Controlled temperature heat
Early modern behaviour It is now generally accepted that the modern human line appeared in Africa before 100 000 years ago. But when did modern behaviour first appear and how did this affect humankind’s expansion out of Africa? Scientists use what are called proxies such as artistic expression – cave painting, use of jewelry and so on – as evidence of the development of modern behaviour. In the same way, an advanced technology that requires a production chain, will provide evidence of modern behaviour. Such technology needs a language to make sure that the chain of production works and remains working over a long period of time and is passed between people without mistakes creeping in. Most research so far has found evidence of advanced technology in ‘bursts’ – it looks as though it appears and disappears during geological time. For example, research to date has suggested that the tools that are characteristic of advanced stone age technology appeared briefly between 65 000 and 60 000 years ago during the last major glaciation and then vanished. Many scientists accepted that there was a ‘flickering’ pattern of advanced technologies in Africa. This pattern was thought to occur
The Pinnacle Point locality showing the cave opening. Image: Erich Fisher
Microlithic blades showing how they have been shaped into sharp, potentially penetrating points. Image: Simen Oestmo
because small populations struggled during harsh climate phases, inventing technologies and then losing them because the artisans in these small communities who had this special knowledge were wiped out by chance events. This research turns that idea on its head. ‘Eleven thousand years of continuity is, in reality, an almost unimaginable time span for people to consistently make tools the same way,’ said Marean. ‘This is certainly not a flickering pattern.’ It is more likely that the appearance and disappearance was because there are so few wellexcavated sites in Africa. The true significance of this find lies in our understanding of the evolution of modern human behaviour and ▲ ▲
The locality at which this technology was discovered (Pinnacle Point 5-6) preserves around 14 m of archaeological sediment that dates from approximately 90 000 to 50 000 years ago. One of the features of the excavation at this locality is that there has been continuous work there for nine two-month seasons. Every item that was found that related to human behaviour was plotted directly onto a computer using a ‘total station’. This is a surveying instrument that digitally captures points to millimeter accuracy where items are found to create a 3D model of the excavation. Almost 200 000 finds have been plotted to date and excavations continue. This was joined to over 75 optically stimulated luminescence dates by project geochronologist Zenobia Jacobs at the University of Wollongong (Australia), creating the highest resolution stone-age sequence from this time span. Optically stimulated luminescence dating is a method that determines how long ago minerals were exposed to daylight. This method can date from around 300 to 100 000 years ago.
Quest 8(4) 2012 23
Fire treatment of silcrete flakes.
Image: Simen Oestmo
the significance of this for the early modern humans who left Africa. ‘When Africans left Africa and entered Neanderthal territory they had projectiles with greater killing reach, and these early moderns [humans] probably also had higher levels of pro-social (hyper-cooperative) behaviour. These two traits were a knockout punch. Combine them, as modern humans did and still do, and no prey or competitor is safe,’
The excavation team at Pinnacle Point.
Image: Erich Fisher
said Marean. ‘This probably laid the foundation for the expansion out of Africa of modern humans and the extinction of many prey as well as our sister species such as Neanderthals.’ ❑ Kyle Brown has been involved in research into Africa archeology and human origins since 1995 and has conducted work in the United States, Kenya, Israel and southern Africa. He specialises in the analysis of stone tools and the experimental
reproduction of technology from southern Africa. Kyle has assisted in directing excavations at Pinnacle Point since 2006. Curtis Marean is an archaeologist at the Arizona State University in Tempe who studies early modern humans in South Africa. He is the Associate Director of the Institute of Human Origins at ASU, and specialises in human adaptation, evolution and diversity and societies and their natural environments. He also has a keen interest in conservation and biodiversity.
BLACK KHAKI 082404R
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To view our fields of expertise, visit the website and/or mobisite Office of the Vice-Rector: Research and Planning 018 299 2606 firstname.lastname@example.org nwuresearch.mobi nwu.ac.za
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24all Quest 8(4) 2012 It starts here
NORTH-WEST UNIVERSITY YUNIBESITI YA BOKONE-BOPHIRIMA NOORDWES-UNIVERSITEIT
A future in mathematics By Prof Johann Engelbrecht (Executive Director), South African Mathematics Foundation
athematics has, through the ages, been seen as the queen of all sciences. Everything in existence is supported by mathematics. Even the prosperity of a country is dependent on mathematics. In the past, mathematics’ main focus was in the field of physics. Although physics is still an important application of mathematics, there are numerous other areas in which mathematics is becoming more important. These areas include computer, financial and biological sciences. Through its crucial role in the development of computer sciences, mathematics reached a turning point. Its further application in the field of financial sciences, especially over the past 30 years, has been responsible for the development of careers such as actuaries and risk analysts, among others. Examples of careers in mathematics include, but are not limited to engineering, statistics and the most recent development, biology. DNA analysis, for instance, is a mathematical theory. Even finger prints and retina scans need mathematics for their classification. This makes biological mathematics one of the most exciting careers that will play a major role in the field of science in the next century. The opportunities in the world of mathematics for Bachelors of Science students are endless. Most South African universities offer a three to four year BSc programme. Entrance requirements at universities differ but in most cases learners should pass Grade 12 Mathematics at a level not lower than 5. When it comes to career advice for those who enjoy mathematics there is one simple question: ‘Are you really crazy about mathematics or do you only love it?’ To those learners who are crazy about mathematics I would suggest an academic career as a lecturer or teacher. Those learners who only love mathematics should
consider a career in which they will apply mathematics such as in engineering or in finance. But whilst you are still thinking about your future career in mathematics you might want to test the playing field by taking part in the South African Mathematical Olympiad (SAMO), which is the biggest Olympiad in the country. It is almost guaranteed that if you participate in the Olympiad and do well, you will achieve academic success at university. Not all learners who do well in maths competitions are considered good at maths by their high school teachers. Maths at school is often simply a matter of learning how to, for example, multiply. Learners will practise their multiplying skill through a number of exercises and every so often learners can achieve fair results without really understanding the subject. Olympiad Maths is focussed more on putting ideas together to solve problems using maths and also using everything else that the learner has read, learnt and experienced. Not only does participation in the
Olympiad prepare you for tertiary studies but it also exposes you to possible bursaries to continue your studies. The South African Mathematics Foundation awarded bursaries to three matric students based on their results during the second round of the 2011 SAMO. The Olympiad is open to learners between grades 8 and 12. Learners who wish to enter this prestigious competition should approach their maths teacher. Entry forms for the 2013 SAMO will be posted to schools early in January. The closing date for entries is 1 February and the first round will take place on 14 March 2013. ❑
Quest 8(4) 2012 25
Figure 2: Richards Bay coal terminal, the largest single coal export terminal in the world. Image: www.rbct.co.za
The life of coal:
ancient forests that power our nation Coal facts and figures
Figure 1: Coal consumption in South Africa. n We are the fifth largest coal producer in the world, with almost 90% of the over 220 million tonnes of saleable coal currently mined per year, produced in Mpumalanga. n We have between 5% and 11% of total global proven coal reserves (depending on who you ask). n We export about 28% of our coal production (64.6 million tonnes in 2011), making us one of the top five coal-exporting countries in the world (most of our exports go to India, China and Europe, and the majority of our coal is exported via the Richards Bay coal terminal). n Coal exports are the third largest generator of foreign exchange for South Africa behind platinum and gold. n Over 75% of our primary energy needs are met through the combustion of coal. n Estimates vary, but at current production levels our coal reserves may last for another 150 - 200 years. If you take expanding demand into account, our coal may run out much sooner, but with increased efficiency of coal use and possible improvements in technology allowing for economic mining and utilisation of poorer quality coal, we may be able to stretch our reserves.
26 Quest 8(4) 2012
As South Africans we rely on coal, not only as our most important primary energy source, but also for many of the products we use in everyday life. Coal pervades our everyday lives. Have you stopped to think where it comes from? Rose Prevec explains. What coal means to South Africans South Africa is one of many nations in the world that has depended heavily on coal for its economic development. In fact, our history has been shaped by our abundant and easily accessible coal deposits. This so-called ‘black gold’ currently satisfies the vast majority of our primary energy needs, and although the serious environmental concerns associated with the use of coal are driving us to seek alternative energy sources, coal will continue to play an important role in our economy for many years to come. South Africans have been using coal as an energy source on a small scale since the Iron Age, but the first commercial use of coal was in 1870, when coal from the Molteno coal field in the Eastern Cape was mined and hauled by ox wagon to the diamond mines in Kimberley. Largescale mining of the Witbank coalfield began not long after, following the
discovery of the Witwatersrand gold field. With the development of our rail infrastructure and as South Africa transformed into a mining giant, the demand for coal to generate steam, compressed air and eventually electricity, increased rapidly. The coal industry continued to expand and also to diversify, playing a pivotal role in the industrialisation of South Africa. Generally, our coal deposits are close to the surface and the seams are horizontal and laterally extensive. This makes mining these seams relatively easy and cheap compared with many other parts of the world. An abundance of coal has allowed many South Africans to enjoy some of the cheapest electricity in the world in past decades. In fact over 90% of our electricity is generated by Eskom’s 11 active coal-fired power stations (with several more being re-commissioned and two under construction), located mostly near our biggest coalproducing areas in Mpumalanga. Beyond meeting our needs for
Above – Figure 5: Coal is used in the production of an astonishingly broad variety of products. Image: Rose Prevec Above right – Figure 6: The carbon present in coal was harvested from the air as carbon dioxide, by vast swamp forests that grew during Permian times. The process of photosynthesis, utilising sunlight as an energy source, allows plants to use water and carbon dioxide to make sugars and other carbon and hydrogen-rich molecules for growth. In coal swamps, mats of dead plant material accumulate to form peat layers. Period flooding brings in mud and sand, and the peat layers become deeply buried over time. Compression and heat gradually alter the plant matter to form coal seams. Image: Rose Prevec
electricity, coal is also central in other core industries, such as in the production of steel, iron and other metals, as well as in the manufacture of cement and bricks. Sasol is a global leader in the use of coal as a source of hydrocarbons for the petrochemicals industry. It is the largest coal-to-chemicals producer in the world, and consumed over 17 000 kt of coal in 2011 alone. Using the Fischer-Tropsch coal-to-liquid process, Sasol converts coal to liquid fuels such as petroleum, producing about 35% of the liquid fuels used in South Africa. However, fuel is just one of many diverse end products of this multibillion-rand industry. Sasol is also the world’s biggest manufacturer of waxes and plastics. They make materials used in the production of polyethylene, lubricants, acrylic fibres used in textiles, house paints, printing ink, candles, crayons, shoe polish, explosives, fertilisers, surfactants in detergents, shampoos, cosmetics… the list goes on!
What is coal? How is it formed? So clearly coal is important to us. But have you ever considered where coal comes from? Why is it called a fossil fuel? Coal is a type of sedimentary rock that is literally compressed, fossilised plant matter, and has such a high carbon content that it can burn. It is hard to imagine a connection between fresh, living green plants
and a lump of coal, or the noxious, synthetic fumes of petroleum and nail varnish, but the chemical foundation of these substances comprises molecules of carbon and hydrogen, originally bonded together by plants that grew in coal-forming swamp forests millions of years ago. Plants, algae and cyanobacteria, which are primary producers, harness the energy from sunlight using the green pigment chlorophyll, and convert water and CO2 from the atmosphere into carbohydrates such as glucose, with the release of oxygen. This process, called photosynthesis, allows the plants to store light energy from the sun as potential energy in the chemical bonds of carbon-rich molecules. Plants then use these compounds as both an energy source and as the building blocks for growth. In a balanced forest ecosystem, plant parts such as leaves, branches, dead trees, seeds and fruits fall to the earth and are then decomposed by the living things of the forest floor, such as insects, fungi and bacteria (detritivores). The plant material is broken down and becomes a part of the soil. But when the accumulation of plant matter occurs more quickly than it is broken down, mats of dead plant material build up. In a swampy, waterlogged environment, the plant matter is permanently or periodically submerged in stagnant water. Low oxygen levels, high acidity and high concentrations of toxic humic acids
Electricity facts and figures
Figure 3: Electricity production in South Africa.
Figure 4: According to Eskom, Kendal is the largest coalfired power plant in the world. Image: www.en.wikipedia.or n 93% of our electricity was produced through the combustion of coal in Eskom’s coal-fired power stations in 2011. n Eskom is the 11th largest generator of electricity in the world, and produces more than half of the electricity used in Africa. n South Africa has 14 coal-fired power stations, three of which were mothballed in 1990 and are now being re-commissioned. Two massive new power stations (including the world’s fourth largest coal-fired power station) are under construction. n The gold mines are the single biggest consumers of electricity in South Africa.
Quest 8(4) 2012 27
Figure 8: The geological timescale is based primarily on extinction events observed in marine deposits. The boundaries between the Periods represent major shifts in the diversity of life on Earth. Geochronologists (scientists who date rocks using a variety of chemical analytical methods based mostly on lead-uranium isotope ratios) strive to assign absolute ages to the divisions on the geological timescale. The coal-forming Glossopteris forests grew throughout the Permian Period, before becoming extinct at the PermianTriassic Boundary. Flowering plants, which represent the vast majority of terrestrial plants today, only became a significant part of the world’s flora during the Cretaceous Period.
South Africa during the Permian Period
Figure 9: The Earth during the Permian Period. Image: The Palaeomap project: www.scotese.com
Models of how the Earth looked during the Permian Period show that South Africa was part of a supercontinent called Gondwana, that was later torn apart by tectonic processes into the chunks that we now recognise as Africa, Madagascar, Falkland Islands, South America, Antarctica, Australia, New Zealand and India. At this time, the supercontinents Laurasia (later to become North America, Europe and parts of Asia) and Gondwana had joined together to form a huge landmass called Pangea. In the past, earth scientists, such as geologists and palaeontologists, compared the rocks and the associated plant and animal life in the fossil record in different parts of the world, and they were able to see similarities that indicated which landmasses were once connected. For instance, the very broad distribution of coal-forming Glossopteris-dominated forests across South Africa, South America, Madagascar, India and Australia lent support to the theory that these continents were once joined together. These ideas were reinforced as our understanding grew of how continents move in response to tectonic forces beneath the Earth’s crust.
28 Quest 8(4) 2012
Figure 7: Most of South Africa’s economically viable coal is concentrated in the northern and north-eastern parts of the Karoo Basin. These coals are all of Permian age. Eskom’s coal-fired power plants are situated near the major coalfields, to reduce the cost of coal transportation. The only actively mined coal of Triassic age in South Africa is the Molteno coalfield in the Eastern Cape.
inhibit the activity of detritivores, reducing the rate of decomposition. This leads to the accelerated accumulation of plant debris. When the resident plant communities are highly productive, and shed a large amount of dead material, this results in the formation of thick peat layers. Occasional flooding of the forest floor covers these peat layers in sand and silt, and slowly over time the peat layers become deeply buried. Heat and pressure from the overlying sediments gradually alters the peat, driving off water and concentrating the carbon in increasingly compressed layers. This process is called coalification. So coal is found in seams (layers) that vary in thickness from less than a millimetre to several meters, and that are layered between other sedimentary rocks. Peat accumulation is a slow process, particularly in cooler climates, and considering that peat compacts to about one tenth of its original volume during coalification, it would have taken many thousands of years for enough peat to have accumulated to produce mineable coal seams. The Permian coal forests of South Africa Most of South Africa’s economically viable coalfields are Permian in age (between 300 and 255 million years old), and are concentrated in the northern and north-eastern parts of the country. These coalfields are what remain of ancient swamp forests that grew in a setting very different to the landscapes we see in South Africa today. South Africa was much further south during Permian times than it is today, and had just emerged from
the grip of a major ice age during the Carboniferous Period. During this ice age most of the supercontinent Gondwana was covered by an ice sheet that was several kilometres thick in places. As the ice sheet and glaciers retreated, they fed a large inland sea, the Karoo Sea, that covered about two-thirds of the interior of presentday South Africa. Along the northern and north-eastern shores, the sea was shallow, and huge rivers produced vast delta systems as they emerged from the glacially scoured valleys and flowed into the sea. It was on the broad floodplains of these rivers and in the swampy delta settings, in a cool, temperate post-glacial climate that the great coal-forming swamp forests of South Africa grew. The Glossopteris forests During the Permian Period, the plants and animals were very different to those we know today. This was an age before dinosaurs or mammals walked the Earth, and it would be 100 million years before flowering plants evolved. The world’s forests were filled with a rich diversity of spore-producing plants, including bryophytes (mosses, liverworts), and both tree-sized and herbaceous lycophytes (club mosses), sphenophytes (horsetail ferns) and ferns, as well as a host of seedproducing plants belonging to the gymnospermous conifers, ginkophytes and seed-ferns. Throughout Gondwana during the Permian Period, the floras were overwhelmingly dominated by a strange group of seed ferns called the glossopterids. The leaves of the glossopterids were first described in the late 1800s in India, and they were first thought to be ferns. The leaves are simple, with
Figure 11: Prof. Edna P Plumstead (1903-1989), the renowned South African palaeobotanist, was the first to describe the strange fertile structures of the Glossopteris plant found in organic connection to leaves. Middle: The unlikely arrangement of these seed-bearing structures is still a source of debate among palaeobotanists; Scutum attached to the midrib of a Glossopteris leaf. Image: Anderson and Anderson, 1985
Figure 10: Fossilised Glossopteris leaves.
Figure 12: Reconstruction of the Glossopteris plant – at least some of the plants that produced Glossopteris leaves were large trees. Right: fertile organs (from top to bottom) Lidgettonia, Eretmonia, Rigbya, Scutum and Arberia. Image: Rose Prevec
base of a Glossopteris leaf or on its midrib, with the seed-bearing surface orientated towards the leaf. The male fertile organs of the glossopterids were reduced (scale) leaves that produced clusters of tiny pollen sacs in clumps attached by means of slender stalks near the base of the scale. In some cases these scales have been found attached to stems in a loose cone-like arrangement. Although the glossopterids probably filled multiple niches and grew in a diversity of habitats, at least some are known to have been large woody trees. We see evidence of this today in the impressions of great tree trunks in sandstones associated
with coals, and also in the trunks of permineralised wood that we find in Permian-aged rocks. The roots of the glossopterids (called Vertebraria) have a characteristically jointed appearance, due to the presence of air chambers. This was an adaption for growth in waterlogged, oxygen-poor soils, and allowed for the diffusion of oxygen from the above-ground parts of the plant into the root system. The glossopterids probably evolved during the Carboniferous Period (see Figure 8) and colonised Gondwana as the ice sheets retreated and opened new niches in moist, cool swampy settings. The reign of the glossopterids ended abruptly when they fell victim to the most devastating extinction event in Earth’s history at the end of the Permian. The end of the Permian coal floras The Permian-Triassic extinction event (also called the Permian mass extinction), occurred about 252 million years ago, and resulted in a nearly complete turnover of life in the
an entire (smooth) margin, and have a central midrib made up of multiple parallel veins. Secondary veins then divide and join across the blade of the leaf to form a network. Although leaves of this type were later found throughout Gondwana, it was only in the 1950s that a South African palaeobotanist, Prof. Edna P Plumstead (based at the University of the Witwatersrand), published conclusive evidence of the fertile structures of the Glossopteris plant. These seedbearing organs are unlike anything known before or since in the plant kingdom. They bore clusters of seeds on one surface of a thickened leaf-like organ that was attached either at the
Image: Rose Prevec
Quest 8(4) 2012 29
Figure 13: A variety of glossopterid seed-bearing organs of the Glossopteris plant: (left to right) a typical winged glossopterid seed; Scutum; Gladiopomum; Ottokaria; Rigbya; Lidgettonia and Eretmonia with pollen sacs borne in clusters on a scale leaf. Image: Rose Prevec Right – Figure 14: Vertebraria, the characteristic root of the glossopterids. Its jointed appearance results from the presence of air chambers – an adaptation to life in swampy, anoxic soils. Image: Rose Prevec
Figure 15: Glossopteris leaves showing evidence of plant-insect interactions (arrows), in the form of margin and hole feeding traces and elliptical oviposition scars where an insect laid its eggs in the leaf tissue. The darker staining rims around the damaged areas represent scar tissue development, showing us that the plant was alive and responded to the damage when it occurred. Image: Rose Prevec Amazingly, it is possible to see evidence in the fossil record of how insects used plants in the past. Since certain types of damage to plants can be related to certain types of insect activity, such as ways of feeding on the leaf or laying eggs in the plant tissues, it is possible to make indirect observations that tell us how insect diversity changed through time.
30 Quest 8(4) 2012
oceans and on land. The plants and animals we see in the Late Permian fossil record are very, very different to those that we see in rocks of Middle to Late Triassic age. Estimates vary, but over 90% of all life in the oceans, and 70% of all terrestrial life became extinct. How this happened, and at what pace these changes occurred, is a matter of on-going debate. Some of the most believable explanations involve the sustained release of large quantities of CO2 into the atmosphere, an associated acidification of the oceans and elevated global temperatures due to an intense and sustained ‘greenhouse’ effect. Many scientists consider the most likely source of this CO2 to have been the massive volcanic eruptions that occurred in what is today northern Siberia, at precisely the same time that the Permian-Triassic extinction was in progress. So-called fissure eruptions poured out up to 4 million km3 of lava during the formation of what is today known as the Siberian Traps (‘traps’ from the Swedish for ‘steps’, after the step-like features typical in this type of volcanic landscape). There is evidence that the lavas burned explosively, using up millions of tons of coal during these eruptions, releasing huge volumes of CO2 and ash in the process. Widespread ocean anoxia and extremely high global temperatures
were a feature of the Early Triassic, and it took many millions of years for the Earth’s ecosystems to recover levels of diversity that were anywhere near those seen before the end-Permian catastrophe. And so we have a cycle. We are burning carbon harvested by long-extinct Glossopteris forests that probably died out because of elevated CO2 levels in the atmosphere at the end of the Permian, leading to increases in temperature and acidification of the oceans. It took several hundred thousand years for life to nearly die at the end of the Permian, but our current emissions of CO2 and other greenhouse gases are causing climatic changes measureable in a time-frame of decades. As we strive to keep pace in a technologically-dependent, energy-hungry world, immersed in factory-produced, highly processed commodities, it is easy to lose track of where the things around us really come from. Consider the essence of the ‘stuff’ you use, as you drive your car, play a CD, wash your hair, switch on the lights. The printing ink that defines the words you are reading and the graphics you are seeing on this page, contain carbon atoms harvested from the air by Glossopteris trees in ancient coal swamps, over 260 million years ago. ❑
Rose Prevec is one of only three resident palaeobotanists working on macrofossil plants in Africa. Based at the Albany Museum and Rhodes University in Grahamstown, her research focuses on the Permian floras of South Africa. Working in this amazing field allows her to spend time outdoors exploring for and excavating fossils, as well as time in the laboratory preparing and describing specimens and producing photographs, illustrations and reconstructions of the specimens and the plants and floras they represent. Rose studied plant pathology at the University of KwaZulu-Natal in Pietermaritzburg before finally pursuing her dream of studying palaeontology, at the Bernard Price Institute, University of the Witwatersrand.
The dark side of coal
References and additional reading BP: www.bp.com; BP Statistical Review of World Energy, 2010 Carbon Disclosure Project: www.cdproject.net Chamber of Mines, South Africa: http://www. bullion.org.za Department of Energy, South Africa: www.energy. gov.za Eskom Holdings Limited: The Eskom Factor 2011. Report available at www.Eskom.co.za The Palaeomap project: www.scotese.com Anderson JM and Anderson HM. Palaeoflora of southern Africa. Prodomus of southern African megafloras Devonian to Lower Cretaceous. 1985. AA Balkema, Rotterdam. Balmer M. Household coal use in an urban township in South Africa. Journal of Energy in Southern Africa. 2007;18(3):27-32. Beerling D. The Emerald Planet: How Plants Changed Earth’s History. 2007. Oxford University Press, Oxford, UK. Benton MJ. When life nearly died: the greatest mass extinction of all time. 2005. London: Thames and Hudson. MacRae C. Life Etched in Stone: Fossils of South Africa. 1999. Geological Society of South Africa. McCarthy T and Rubidge BS. The Story of Earth and Life: a southern African Perspective on a 4.6 billion-year journey. 2005. Struik, Cape Town. Prevec. RA. Structural re-interpretation and revision of the type material of the glossopterid ovuliferous fructification Scutum from South Africa. Palaeontologia africana 2011; 46:1-19. Snyman,P. Coal. In: The Mineral Resources of South Africa (Wilson, MGC and Anhaeusser CR eds): Handbook, Council for Geoscience, 1998; 16, p. 136-205. Sun Y, Joachimski, MM Wignall, PB Yan, C Chen, Y Jiang, H Wang, L Lai, X. Lethally hot temperatures during the Early Triassic greenhouse. Science 2012; 338: 366. Taylor TN, Taylor EL, Krings M. Paleobotany: The Biology and Evolution of Fossil Plants, Second Edition. 2009. Burlington, MA. Academic Press.
Figure 16: Open cast pit at the Rietspruit coal mine.
Image: Rose Prevec
The coal industry is a huge polluter. Both the mining and combustion of coal have very severe impacts on the environment. Open-cast mining is an ecologically devastating process. All surface soil and vegetation is stripped away, the bedrock is blasted, coal is extracted, and then the pit is backfilled. Legislation requires that the ground is rehabilitated, but it is not possible to replace the biodiversity lost through such a destructive process. The coal industry also generates large amounts of waste, in the form of discards from the beneficiation of coal for export (beneficiation is the use of mechanical methods to increase the concentration and quality of coal). More than 65 million tons (Mt) of coal discards are produced every year in South Africa. In coal-fired power stations, coal is burned to heat water, generating steam to drive turbines that produce electricity. This is a water-intensive process, and Eskom is currently responsible for 2% of the entire country’s water consumption, amounting to 327 billion litres of fresh water in 2011. Huge amounts of water are also used during coal mining and beneficiation processes. Household coal use accounts for 2 - 3% of coal consumption in South Africa, which is huge considering how much is used in industry and electricity production. Nearly a million homes use coal as a household energy source, concentrated in areas near coal mines, and where winters are severe. Coal provides a cheap and readily available source of domestic energy to low-income households, where it is burned in stoves for cooking and heating. But its use leads to very high levels of localised air pollution, resulting in an increased incidence of respiratory diseases. Studies have shown that 48% of particulate emissions in Johannesburg could be attributed to domestic coal burning. Poor ventilation of households, especially in informal settlements and rural villages, increases the concentrations of the pollutants within the home environment, and amplify the negative effects. Unscrupulous dealers are also known to sell sub-standard coal from discard heaps, that doesn’t burn well and generates a lot of smoke. Respiratory infection caused by air pollution is the sixth largest cause of child mortality in South Africa. Electrification of low-income areas may help to reduce dependence on coal use within the household, but coal is still cheaper for most people once you factor in not only the cost of electricity itself, but also the electrical appliances required to make use of this power source. Burning coal releases massive quantities of carbon dioxide into the atmosphere. South Africa’s heavy dependence on coal means that we are among the top 20 emitters of greenhouse gases in the world (estimated 500 million metric tonnes in 2010), and the top emitter in Africa. Eskom emitted about 230 Mt of CO2 in 2011, through the combustion of 124.7 Mt of coal, in addition to sulphur dioxide and nitrogen oxides (SO2 and NOX) and particulates. Eskom contributes about 45% of South Africa’s total CO2 emissions, compared to a global average of 26% for the power sector. Sasol, another big CO2 emitter, released 75.3 Mt of CO2 in 2011, and contributed about 11% of South Africa’s total greenhouse gas emissions. While acknowledging that South Africa is a developing nation, facing poverty and unemployment, a struggling education and health system, the government has expressed a commitment to addressing our large carbon footprint. Coal is not a renewable resource. We have plenty of it, but we will eventually get to the point where it is no longer economically viable to rely on coal as our primary energy source. We have already reached this point in another sense, when we factor in, on a global environmental scale, the enormous cost of using fossil fuels.
Quest 8(4) 2012 31
The shoreline of Table Bay around 1790. The building indicated by the arrow is La Caille’s observatory or a building of similar size in its place. Image: From a painting by Samuel Davis, Western Cape Archives and Record Service, M799.
Nicolas-Louis de la Caille The year 2013 marks the 300th birthday of the astronomer Nicolas-Louis de la Caille, the first important scientist to visit the Cape, during the years 1751 – 1753. By Ian Glass.
Portrait of La Caille by Anne-Louise Le Jeuneux (1762). Image: SAAO
Principle of La Caille’s instruments: The frame of the instrument was set up in a north-south direction and perpendicular to the ground. The angle from the vertical at which the telescope was pointing was read off the scale. A pendulum clock nearby gave the time of transit of a star from east to west. Behind the eyepiece was an elaborate reticle that subdivided the 3-degree field of view. The celestial coordinates could then be calculated.
32 Quest 8(4) 2012
a Caille was a member of the Royal Academy of Sciences in Paris and a professor at the Mazarin College. He had his own observatory on the roof of the building and devoted his life to studying the positions of stars and planets. His data were among the most precise of the time and were eagerly awaited by the young French mathematicians Maupertuis, d’Alembert and Clairaut, who were Newton’s successors in progressive mathematical thinking. Many of the older French academicians could not bring themselves to accept Newton’s law of gravity, which operated across the vacuum of space and smacked of the occult. The theory of their countryman Descartes, which involved ‘vortices’ in an invisible medium between the solar system bodies, seemed to be more physical and reasonable. La Caille however belonged to a new generation and made it his business to propagate Newtonian theory in his textbooks on mathematics, astronomy and mechanics. To determine the orbits of the planets and their moons it was necessary to measure their angular positions and find their distances. This was done by plotting their paths relative to the fixed stars. It was easier to get star positions than planetary ones because the measurements could be repeated as often as necessary. The distances of the planets could be found by triangulation, but this was not easy and required the most accurate instruments available. The
bases of the necessary triangles had, of course, to be on the Earth. The angles towards the planet from each end were found by astronomical instruments. Since planets are so far away, the triangles are extremely narrow. La Caille realised that the best results would be obtained if the baseline was as large as possible. It could not be confined to France but should be extended across the Earth. For this reason he asked the French government to underwrite an expedition to the Cape, the most accessible southern hemisphere location for Europeans. Of course, he also had to arrange that other astronomers would make measurements from European locations at the same time that he expected to be observing at the Cape. Once arrived at the Cape, La Caille rented rooms in a house near the shoreline of Table Bay and constructed a small observatory in its back yard. In it he mounted his instruments after checking them carefully to see that they had not been damaged or distorted while at sea. As soon as he could, he set about surveying the southern sky. His was the first ever systematic survey of any part of the sky by telescope. Surveying the southern sky His technique was to set his telescope at a fixed angle to the vertical for a whole night and to note the time at which the rotation of the earth caused the stars to pass through his telescope. Since he measured a band of about 3
Q History of science
degrees wide, he had to observe 25 zones between the Tropic of Capricorn at 23.5 degrees south and the pole at -90 degrees. In one night only about one-third to one-half of the Earth’s rotation was covered so he usually had to observe each zone three times, spaced around the year, to get all the stars. Fortunately the Cape weather is quite good, so that he was able to finish his programme in only 12 months. He remarked sadly that this type of work would have been impossible in the climate of Paris. As can be imagined, he did not find it easy to keep his head at the eyepiece all night in some awkward position. He had a special headrest made for support. He had to make notes of the exact position of each star in the eyepiece and the exact time at which it passed from the eastern to the western hemisphere as he went along. His only company was a dog called Grisgris that he had found as an abandoned puppy as he left France. One can imagine the relief he felt when he wrote in his notebook at the end of his survey that he had been able to sleep in a proper bed for the first time in a whole year. The result of his labours was a catalogue of star positions that was not improved upon for around 80 years. Because the constellations were few and far between in the southern sky, he had to introduce 14 new ones, including Mons Mensa (Table Mountain), the only terrestrial place with a counterpart in the heavens. His constellation names are still used.
La Caille’s map of the Cape, showing his survey triangles. The ‘base’ was measured laboriously by means of surveying rods and used to calibrate the other distances. Image: SAAO
Measuring the distance of a planet by trigonometry. The angle π was in reality very small and the best results were obtained when the baseline stretched as far as possible across the Earth.
Quest 8(4) 2012 33
La Caille, lying down and looking through the telescope, is seen with an associate reading the scale of the zenith sector. This picture illustrated the account of a previous survey made in France. However, the same instrument was used to find the difference in longitudes between Cape Town and the Piketberg. Image: SAAO
The shape of the Earth as determined by La Caille (greatly exaggerated).
Finding the radius of the Earth to find the positions of the planets In between star observations he made measurements of the positions of the planets at the dates and times that he had agreed with his colleagues in Europe. To find the length of the baseline between the Cape and (for example) Paris he had to calculate it from the latitude of the two places. But this involved assuming that the Earth was some particular shape. Previous measurements in the northern hemisphere by members of the Academy had shown that the Earth was slightly flattened towards the north pole, but nobody knew if it had the same shape in the southern hemisphere. Thus La Caille decided he had to measure the radius of the Earth in the south. The Cape Swartland with its flat plains and isolated mountains
34 Quest 8(4) 2012
was ideal for this purpose. The radius of the Earth was measured in two basic steps. La Caille determined the difference in latitude astronomically between his observatory on the Cape Town foreshore and a temporary second observatory on a farm in the Piketberg region about a degree away towards the north. He also then had to make a precise measurement of the distance between the two observatories on the ground. To do this he used two large triangles. The shared base of these two triangles was the line joining the Kapokberg to the Kasteelberg. However, this base had to be calibrated and involved laying out a line about 12.6 km long nearby. Using more triangles, he was able to calibrate the Kapokberg – Kasteelberg distance and hence work out the separation of the Piketberg from his observatory in Cape Town. But unfortunately he got the wrong answer. According to his result, the Earth was pear-shaped. The problem was not due to carelessness on his part but rather to the fact that the gravitational attraction of Table Mountain at one end and the Piketberg at the other end had deflected the plumb line on the latitude-measuring instrument from the true vertical. In fact it was Everest (of Mount Everest fame) who pointed out the probable error during a visit he made to the Cape in 1820. The final correction was made by Maclear, of the Royal Observatory, Cape of Good Hope, in the mid-nineteenth century. La Caille made many other contributions to science. For example,
during his four-month voyage to the Cape, the difficulties faced by ships’ captains in finding their positions were vividly brought home to him. It was easy enough for them to get latitudes by observing the angular heights above the horizon of bright stars or the poles but finding longitudes depended on having accurate clocks. Unfortunately, in those days the only good clocks made use of pendulums which were useless in rolling and pitching ships. Halley in England had suggested that the Moon’s movement among the stars could be used as a kind of clock but unfortunately its position could not be predicted accurately enough. La Caille, in later life, was able to produce the first sufficiently accurate tables of the Moon’s position, based on his observations and Clairaut’s theorem. These tables and their successors were the basis of accurate navigation until marine chronometers became widely available in the nineteenth century. Only a few years remained to La Caille after his return to France. He carried on teaching at the Mazarin College and one of his pupils was the chemist Lavoisier, who freely acknowledged his debt to the precise methods taught to him by La Caille, for example in the discovery that mass is conserved in chemical reactions. La Caille was involved in observing the return of Comet Halley in 1758. In fact it was he who gave the comet its name. The voyage to the Cape made La Caille a hero to the French public of the time and his lectures on his voyage and discoveries were eagerly attended. He left behind a ‘Historical Journal’ of his experiences and included within it some interesting accounts of the places he had visited and the customs of the European colonists, their slaves and the Khoina indigenous people. La Caille died in 1762 of an illness that he may have picked up at the Cape but the symptoms described are insufficient for a diagnosis. He was only 49 years old. Dr Ian Glass is an astronomer at the South African Astronomical Observatory. His interests include infrared astronomy and astronomical history. He is the author of several books and his latest, Nicolas-Louis De La Caille, Astronomer and Geodesist, will be published in December 2012.
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Improving community health Juanette John describes health impact assessment – a tool for identifying opportunities for improved community health and wellbeing.
Top: A simple way to make a watering can.
Image: Juanette John/CSIR
Top right: There may even be opportunities arising from waste dumps. Image: Juanette John/CSIR Above: ’Sophia’ standing next to a large drum of water. Image: Juanette John/CSIR
36 Quest 8(4) 2012
What does it mean to be healthy? Health starts at home, but also in our schools, suburbs, and our communities. We learn at school that there are many different things that influence our health and that we need to take care of ourselves by: eating healthy food and being active, not smoking, being immunised and seeing a doctor when we are sick. But our health is also partially as a result of other ‘nonhealth’ things such as: the resources and support systems available in our homes and communities; the quality and safety of our school environment; the cleanliness of our water, food and air; and the nature of our social interactions and relationships. The combination of all these conditions explains in part why some South Africans are healthier than others and why some people are not as healthy as they could be. These factors are called social, economic and physical determinants of health. They may play a role in improving our health (if we have easy access to clean drinking water), or they may be hazards and threaten our health (if our drinking water is polluted). Hazards are those factors or conditions which have the potential to pose a threat to human wellbeing. Meet Sophia. What does her living environment look like? Sophia lives in a (fictitious) town,
Enervale with her grandmother and two younger brothers. Their suburb is very close to a stream and a big factory upstream from them. The factory emits air pollutants and sometimes discharges waste water into the stream, which runs past their house. Sophia has asthma which becomes worse when the wind is blowing from the direction of a factory that is situatiated near their house. On the upside, Sophia’s family lives in a small house with two bedrooms and an insulated roof (a ceiling). Although they don’t have running water inside the house, they have a tap in their garden. Sophia’s grandmother also has a vegetable garden and a peach tree and some chickens from which they get eggs for protein. The children water the garden with watering cans they make from used milk bottles or old tins and use the compost they make with leaves and vegetable peels. They have access to electricity but because they live off her grandmother’s pension and a foster-care grant, they often cook on a paraffin stove or sometimes even an open fire (imbawula). Her grandmother did, however, teach them the basa njengo magogo or top-down method which causes much less smoke. This method of making an open fire involves placing a few lumps of coal on the top of the fire at the right time. In an open fire, smoke is generated at the hot/cold boundary.
Q Environmental Health
The basa njengo magogo fire is the one burning brightly on the right of the picture. There is far less smoke than in the traditional fire on the left. Image: CSIR
So if the hot coals are placed at the top of the fire, the smoke rises through the hot coals and is burnt off, which causes less air pollution.
n Is there a chance that the proposed project will have health concerns?
Scoping n What types of hazards and positive impacts are there? n Who may be at risk?
Baseline data n What is the status of these hazards at the moment? n What positive things are happening?
Risk assessment n How serious is the effect of these hazards?
Health Action Plan addressing risks identified n What should be done? n Who should do it?
Monitoring and evaluation n What data should be gathered to measure how things are? (indicators)
As a result these developments often have to stick to a set of environmental and social benchmarks that help to manage the risks that they encounter. So developers have increasingly been required to consider health within their assessment processes, which means
Yes. The water, air is already polluted and many people are already affected.
Air and water pollution. Other pollutants, e.g. from cooking fires, existing factory, motor vehicles. Children, people with compromised immune systems in the community.
Concentrations of air and water pollutants. Current health status of people – proportion of children, people with asthma? Positive: some people grow their own fruit, vegetables, good fire-making practices.
Risks posed by n air and water pollutants n nutritional status n children not completing school
Different role players: n Industry should put systems in place to ensure that water and air is not polluted. n Municipality responsible but everyone has a role to play to improve service delivery. n Industry and community can work together to identify capabilities and assets of community.
Indicators should measure: n whether risks are being reduced, e.g. air and water quality n whether opportunities within the community are being used.
that they may have to carry out a health impact assessment (HIA) as one of the specialist studies. The main objective of the HIA is to maximise positive health impacts and to minimise negative effects. This process does not only consider problems that the development
New development in town? Last week Sophia saw on a poster in the library that another factory similar to the one that is already there wants to start up in the area and they are doing an environmental impact assessment (called an EIA) to determine if it is feasible to do so. Today Sophia’s teacher told them to find out what this process means and how it may affect the health and wellbeing of the local community. When she Googled the EIA process on the internet in the library, she discovered that a developer indeed needs to show that a proposed development, such as a power station or a mine, will not cause a significant adverse impact on the environment or on the economic, cultural and social well-being of the people in the community. A screening process is done first to decide if the development might have significant adverse impacts on the environment, or might cause public concern. If so, the application has to go through an environmental assessment, during which potential concerns are evaluated through different specialist studies (including concerns around potential impacts on inflow of job-seekers to the area and concerns around the potential impact of the development on the natural environment, such as water and air quality). Sophia thought for a moment about the situation in their town – air and water quality, for example, is already a problem in her area. She also found out that EIA regulations in South Africa do not specifically require that human health impacts be considered, although more than 60% of concerns raised during EIA public meetings are around the possible impacts that a project or development may have on human health. Times are, however, changing. More recently, some development projects have been getting international funding.
Quest 8(4) 2012 37
References Harris-Roxas B, Viliani F, Bond A, et al. Health impact assessment: the state of the art, Impact Assessment and Project Appraisal 2012; 30:(1): 43-52. Social Determinants of Health. Available from: http://www.healthypeople.gov/2020/topicsobjectives2020/overview. aspx?topicid=39. (Accessed 15 Nov 2012). WHO, 2012. Health Impact Assessment. Glossary of terms. http://www.who.int/hia/about/glos/en/index1.html (Accessed 15 Nov 2012).
The only source of water for Sophia and her family. Image: Juanette John/CSIR
Sophia’s grandmother’s small vegetable garden. Image: Juanette John/CSIR
may cause (risks), but also identifies opportunities that it may create in the community. Some problems have to be addressed at higher levels (such as by industry, or the government), an example being the cleaning up of polluted air and rivers, or provision of adequate services such as water and sanitation. However, in some cases people in the local community can play a role in discovering a disguised opportunity in a problem – for example garbage being dumped and often burnt, which creates air pollution, may result in an opportunity to create products from waste. Sophia thought about all the plastic bottles and cans that people were just dumping and how they were able to make watering cans from these. An exciting thought entered her mind. Perhaps they can even make other things from these! Engaging the Enervale community Sophia was able to go with her teacher to the public meeting. The speakers emphasised the importance of different stakeholders, including people from the community, having the opportunity to give inputs to the process. During the
38 Quest 8(4) 2012
meeting concerns were raised that the air and water is already being polluted and that the proposed development may make it worse. It was also noted that there are people in the community who are susceptible to these pollutants (more in danger of getting sick), including children because their bodies are still developing, people with asthma (like Sophia) and people who have illnesses that reduce the efficiency of their immune systems. People also asked what skills the new development would require and indicated that many school children in the area are not able to complete their school education because they are in child-headed households. It was decided that an EIA was indeed required, which would include specialist studies such as a water quality study, an air quality study, a social impact assessment and an HIA. What was included in the HIA study? The HIA followed a specific process, asking questions to gather the best possible information to decide whether it is possible to maximise positive health impacts and to minimise negative effects given what will happen should the development go ahead. What was the outcome of the HIA study? Community input to the scope, findings, and recommendations of an HIA helped to take the local context into account, which improved the accuracy of the analysis. This helped not only to improve the quality of the process but also ensured that community members have a stronger voice in decisions that affect them and are involved in identifying opportunities. The HIA indicated that there were risks that had to be considered, but that there were also opportunities that could help improve the health and wellbeing of the community should the development go ahead. The Health Action Plan indicated how and by whom risks could be minimised and opportunities developed. These findings will now be included in the EIA process and communicated to the community, after which a decision will be made as to whether this development can
go ahead. Sophia’s teacher promised to get the report and share it with the class once it is available so that they can understand what it means for them as community. What can be learnt from this example? Development is important because it has the potential to bring economic benefits to people. But development should be sustainable, thereby protecting and improving the health of both people and the planet. It is therefore not only about improving the conditions in which we live, learn, work and play, but also about strengthening existing skills and the quality of relationships in our communities. All these things are essential ingredients for a healthier population, society and workforce. Everyone living in South Africa, including Sophia and her family, should have opportunities to make choices that lead to good health. But in order to enable these opportunities, changes may need to be made, not only in health care but also in fields such as education, childcare, housing, business, law, media, community planning, transportation and agriculture. This would require that people in different fields work together to achieve common goals that will help to achieve this, instead of working against each other. Prevention is better (and healthier) than cure A doctor cannot write a prescription to install a tap at someone’s house or for fires that cause less smoke. However, processes such as HIAs, and people such as doctors, public health experts and other role players can work with communities to inform decisions in other fields that will help people lead healthier lives. ❑ Juanette John is a scientist at the CSIR with more than 10 years experience in the environmental health field, with a focus on Health Risk Assessment and Vulnerability Assessment. Her research interests are around factors that make communities vulnerable to environmental pollution, how these challenges may guide vulnerability interventions and play a role in the development and function of healthy municipalities.
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1. Landmine detonates
Blast protection How do landmine-protected vehicles protect their occupants from landmine explosions? By Genevieve Langdon.
2. Blast waves impinge on LPV hull
3. Localised hull damage
A casspir at the SA Police museum in Pretoria.
E 4. Local floor movement
5. Global vehicle movement A diagram of a landmine-protected vehicle with a flat hull, showing its response following a landmine explosion.
40 Quest 8(4) 2012
xplosions come in many forms such as detonation of plastic explosives, gas explosions, nuclear bombs and ruptured pressure vessels. Explosions are dangerous because they release huge amounts of energy in very short times â€“ very high pressure (gigapascals) in a few millionths of a second. The detonation of explosives causes high-pressure blast waves that travel through the air and interact with any object in their path. The blast waves are highly destructive, causing tremendous amounts of damage. A landmine explosion is a deadly event. Landmines are an ever-present threat in many parts of Africa and the world, a legacy of past and present conflicts. They also injure civilians more often than the originally intended targets. South Africa, as well as many other countries, is involved in trying to keep peace or clear landmines in some of these areas. This is a hazardous task, requiring well-protected transport for those involved. South Africa was a leader in the design of landmineprotected vehicles for much of the previous century. The big innovation
Image: Wikimedia Commons
was the V-shaped hull, which South African researchers found reduced the damage to the vehicle during a landmine explosion. The people inside these vehicles also had less serious, or no, injuries. South Africa produced vehicles such as the casspir, which are still in use today. People inside the casspirs suffered fewer injuries if the vehicle was involved in an explosion, which contributed to the success of the vehicle. However, although the V-shaped hull was a great innovation, the way in which its shape prevented injuries was not systematically investigated. Reducing the impact of a blast The Blast Impact and Survivability Research Unit (BISRU) has been looking at the reasons why the V-shaped hull provides improved blast performance. There are three important ways in which vehicles respond to a landmine explosion: n Localised damage to the vehicle bottom â€“ rupture and permanent deformation n Local movement of the floor into the personnel compartment
Q Mechanical engineering
Explosion testing at BISRU
This photograph shows a blast-loaded test specimen from the BISRU Laboratory, viewed from the opposite side to the explosion. This specimen was subjected to an explosion of 18 g of PE4 at a distance of less than 50 mm. This experiment was performed to test some possible design variations on the V-shaped hull. The flat part of the plate ruptured in the middle and peeled backwards.
Pressure is a measurement of force divided by area, and the unit used to measure pressure is pascals. For example, if a typical apple (100 g, 0.1 kg) is put on an object and takes up a square area of 10 cm by 10 cm, then the apple would be exerting a pressure of 0.1 x 10 / 0.12 = 100 Pa (if acceleration due to gravity is approximately 10 m/s2). A gigapascal is 109 Pa (or 1 000 million pascals, or the equivalent of 10 million apples in the 10 cm by 10 cm square area).
1. Flat hull, pressure reflected – momentum transfer upwards 2. V-shaped hull, pressure deflected – more momentum transferred sideways
n Global movement of the vehicle due to momentum transfer The low injury rates found in the casspir are thought to be because of the mechanism of load/momentum transfer. If a vehicle is involved in a landmine explosion, the blast wave is directed upwards towards the vehicle. A vehicle with a flat-bottomed hull attempts to absorb the energy by deforming and causing the floor to move into the personnel compartment, but the momentum transfer eventually causes the vehicle to be lifted into the air. However, when a vehicle has a V-shaped hull, the blast wave is deflected sideways. This means that less of the momentum is transferred upwards and the vehicle does not lift off the ground. This also means that less energy is available locally to damage the vehicle bottom. In addition, a V-shaped structure is geometrically stiffer than a flat, plate-like structure, which means that there is less visible damage to the hull bottom. The research At BISRU we have been performing small-scale explosion tests to understand how the internal angle of the V-shaped structure affects the blast performance. At the same time, we build computational models to try and predict the loading and response during an explosion. To model blast performance effectively, we need to build structures out of materials that have the correct properties.
An important part of those models is understanding the properties of the materials that the structure is made from. To get an accurate understanding of these properties, small coupons are machined from the structures and tested at high loading rates. The computational models are very useful in helping us to visualise how the blast waves flow around the V-shaped structures. They also help in the design of full-size vehicles, testing out different types of explosions, because full-scale explosion testing with real vehicles is very expensive. A disadvantage of the V-hull configuration is that it forces the vehicles to have high ride heights. This makes them less stable because the centre of mass is higher – the vehicles could topple over when cornering. Vehicles with V-hulls have to move more slowly, and make big targets on the battlefield. Recent innovations in the design of landmine protected vehicles include looking for other ways to improve blast performance but, at the same time, lowering the centre of mass. Shallow V-shaped hulls, pre-stressed bottoms and contoured profiles have been proposed and some of these are now in use. Novel materials put together like a sandwich have also been proposed for energy absorption in the vehicle bottoms. Some of these are honeycomb materials, composites and polymeric foams. BISRU is continuing its research into blast hull
2 A diagram showing how the blast wave is deflected sideways with the LPV bottom
performance improvements in all these areas. ❑ Genevieve Langdon in an Associate Professor in the Department of Mechanical Engineering at the University of Cape Town (UCT) and an active member of the Blast Impact and Survivability Research Unit (BISRU). Her research investigates the blast resistant properties of lightweight materials such as composites, blast mitigation and the failure modes of structures subjected to dynamic loading. She has a PhD in Mechanical Engineering from the University of Liverpool. She has published her research in many journal articles, conference proceedings, popular media and books. Genevieve is also a chartered engineer and a founding member of the South African Young Academy of Sciences.
Quest 8(4) 2012 41
The Gariep dam – a source of clean water for millions.
Image: Wikimedia commons
A right to safe water supplies Anél du Plessis and Louis Kotzé explain the constitutional right that all South Africans have to enough water and safe water. Millions of South Africans still do not have access to a safe water supply. Image: childfund.org.nz
n 1996, South Africa adopted a new constitution with an entire chapter devoted to a set of basic rights that belong to every person who lives in the country. These rights include, for example, the right to life, the right to human dignity and the right to basic education. One right is particularly important – the right of everyone to have access to sufficient water.
While the right does not guarantee that everyone will have water, it does provide the legal means by which the state provides people with access to water. Not many other countries have access to safe water as one of their rights, one that is particularly significant in South Africa because we live in a dry country where the majority of the inhabitants are poor. Providing our population with sufficient water while we do not have an abundance of water in our surface or underground reserves, requires careful planning by our authorities and responsible use of water generally. While it is everyone’s task to use water with great caution all the time, it is the responsibility of government (parliament, the national Department of Water Affairs, municipalities, water catchment management agencies and other organs of state) to ensure that the constitutional right to water becomes a living reality for all people – no matter where they live, who they are, or what they earn. Not only a legal issue The constitutional right of access to water is not only a legal issue. To fully appeciate how the right of access to water must be protected and enforced by government and respected by
42 Quest 8(4) 2012
Q Social science
ordinary people, South Africa requires a variety of scientists and researchers to work on this subject. It is important, for example, to understand the science behind weather patterns and climate change; the improvement and maintenance of water quality for purposes of human, plant and animal life; the infrastructure necessary to retain, clean and provide water to people; the reasonable cost of water; the quantity of water that municipalities should provide to indigent people who cannot afford to pay for all the water they need; ways to recover costs for water supply and purification; as well as mechanisms and technology to help people and institutions – including farmers, mines and power stations – to use less water. Several important things depend on the availability of water. We need water for human life, agriculture and access to food, sanitation, the extraction of minerals, the generation of energy and the maintenance of complex ecosystems, for example. This explains why it is very important that everyone in South Africa respects the right of access to sufficient water. The duty that rests upon the shoulders of government to provide people with water translates into a duty upon all of us to think about how much water we use and how we use it every
day. Using water with care would not only show respect towards other users (especially indigent users who have little access to this life-sustaining resource), but it will also show respect for the environment and other forms of life that depend on water for their survival. What you can do You can make a direct contribution to protecting and fulfilling South Africa’s constitutional water right by saving water and encouraging your family and friends to do so too. You could become involved with, or start, a project to clean up polluted sources of water in your area – small streams, rivers or local dams. Look to the future and perhaps start thinking about the many different careers in the bigger ‘water sector’. These range from engineering, environmental management and ecology, water law (as a branch of environmental law), agriculture and public administration. It is often said that the next world wars will be fought over water, not land and mineral resources. In an arid country such as ours, millions of people do not have access to clean water that they can use for washing, drinking, cooking and growing food. This places a huge responsibility on us all to care for our precious limited water resources. Doing this will prevent a situation where lack
iSimangaliso Wetland Park. Conservation of South Africa’s wetlands is a vital part of conserving water security. Image: Wikimedia commons
of sufficient water will ever be a threat to our livelihoods. ❑ Anél du Plessis, Professor of Environmental and Local Government Law (North-West University), Member of South African Young Academy of Science (SAYAS) and Representative of the Environmental Law Association of South Africa. Louis Kotzé, Professor of Environmental Law and Governance (North-West University) and Member of SAYAS.
There are many different ways that you can save water. Image: Earth Month Tips
Quest 8(4) 2012 43
A false colour satellite photograph of the Nile Delta. Image: NASA
Changing disease patterns Potential affects of climate change on waterbourne diseases in South Africa. By Kirsty Robinson, Jessica Kavonic and Mischa Minne.
Predicted rainfall and tempertures changes as the average global temperature rises.
44 Quest 8(4) 2012
Image: From IPCC 2007
urrent patterns of climate change are mostly caused by increasing concentrations of greenhouse gases in the atmosphere, in particular carbon dioxide (CO2). The cumulative increase of CO2 that has resulted from human activity since the industrial revolution of the 1750s has been largely accepted by the scientific community as contributing towards changes in global climate and weather patterns. Rainfall patterns, in particular, are predicted to change in frequency and intensity and average temperatures will increase worldwide. In South Africa, rainfall is predicted to increase along the east coast, with
Q Climate change
The current global distribution of malaria.
Image: Wikimedia Commons
A female Anopheles mosquito – the species that transmits the malaria parasite. Image: Wikimedia Commons
A typical mosquito breeding area.
Cholera areas reporting outbreaks, 2010-2011.
Image: World Health Organisation
drier conditions prevailing in the west of country. Overall, the average global temperature is likely to rise by at least 2 ˚C, by the end of this century, but the increase in southern Africa could be much higher, perhaps as much as 4 - 5 °C in some regions. It is likely that these changes and increases in temperatures will affect water-bourne diseases such as cholera, malaria and schistosomiasis, as well as the distribution of insect hosts and vectors. If so, more people will be exposed to these diseases, with potential implications for health care costs.
weather-related events, can change the distribution of the host vectors. A habitat change may also mean that it is more likely that the pathogen comes in contact with humans, increasing the risk of human infection. Malaria
Malaria is a potentially fatal disease caused by species of the parasite Plasmodium. The most dangerous form of malaria is caused by Plasmodium falciparum. Plasmodium is transmitted to humans by a vector – the female Anopheles gambiae mosquito – when the person is bitten by an infected mosquito. According to the World Health Organisation (WHO), in 2010 there were 216 million cases of malaria and an estimated 655 000 deaths. Most deaths occur among children under the age of five. However pregnant women, those with a weak immune systems (for example those infected with HIV/ AIDS) and those who have not had prior exposure to the disease and therefore lack immunity are also at high risk of infection.
The bacterium that causes cholera – Vibrio cholerae. Image: Wikimedia Commons
How will climate change affect the distribution of malaria?
As climate changes, rainfall patterns change and temperatures rise, so the tropical belt expands. This means that mosquitos currently found only in the tropical belt are likely to expand their distribution and occupy new niches. Previously malaria free areas such as Kenya, Rwanda, Burundi, Ethiopia and the mid to northern parts of South Africa are predicted to become suitable habitats for malaria mosquito vectors by 2080. ▲ ▲
Infectious diseases in the context of climate change Most infectious diseases are restricted to tropical and subtropical zones, where they are more prevalent in the warmer lower altitudes. Water-borne diseases often require an animal host (vector) to transmit the disease pathogen. Variability in climate and weather can affect both the vector population and the life cycle of the pathogen within the host. Ecological disturbances, including
Quest 8(4) 2012 45
An itchy skin erruption caused by schistosoma cervariae burrowing into the skin. Image: Wikimedia Commons
Cholera Cholera is caused by the bacterium Vibrio cholerae, which releases toxins that cause increased water loss from the intestine cells of the host, leading to severe diarrhoea and vomiting. This can rapidly cause severe dehydration, which may be fatal, particularly among malnourished people. The bacteria are transmitted through contaminated or untreated drinking water or through food contaminated by the faeces of an infected person. How will changing climate affect the distribution of cholera?
The bacterium that causes cholera is found in coastal and estuarine marine algae, as well as in tiny swimming crustaceans, called copepods. The distribution of these intermediate hosts is likely to be affected by changing sea surface temperatures and other environmental factors, including rising sea level, which will affect the distribution of both hosts and the pathogen. As Vibrio cholera bacteria also multiply faster at higher temperatures, this could lead to more frequent outbreaks of cholera, and in new areas, if appropriate public health measures are not implemented. Schistosomiasis Schistosomiasis (bilharzia) is a fresh water parasitic disease that affects humans. The disease is caused by parasitic worms, which are hosted by fresh water snails. Parasitic larvae (called cercariae) are released from the snails into river water and secrete enzymes that destroy proteins in human skin and underlying tissues. People may be initially unaware that they have been infected since the larvae can remain under the skin for a number of days before entering the person’s capillary system. The disease causes chronic medical problems, including an enlarged liver and spleen, abdominal pain, fever and tiredness.
46 Quest 8(4) 2012
An open drain in Zimbabwe – one of the sources of the cholera outbreak in 2008. Image: Wikimedia Commons
How will climate change affect the distribution of schistosomiasis? At the moment the disease affects mainly rural populations in subSaharan Africa, with almost all infections (90%) occurring on the African continent. The prevalence of schistosomiasis is often linked to irrigation practices, as the snail is spread widely by irrigation infrastructure. The Nile Delta is a good example of this, while in Ghana and parts of China, schistosomiasis incidence has increased after the construction of dams. The distribution of schistosomiasis is largely dependent on the distribution of the diseases’ snail host, so if changing climate alters either the distribution of the host, or it’s freshwater habitat, as is likely, this could influence the life cycle of the disease itself. However, climate change could conceivably suppress the disease if altered climate favours the snail’s predators. Furthermore, any increased competition for food or space may also lead to a decline in snail numbers and therefore restrict the spread of the disease. In short, predicting the affects of a changing climate on schistosomiasis is very uncertain. It may well be that the effects of climate change will be seen more in human manipulation of the waterways where the snail occurs, which will indirectly affect the distribution of the disease. Conclusion Future climate variability could affect water-bourne parasitic diseases in two ways. Firstly, as climate increasingly becomes warmer and dryer, or
wetter, the geographical ranges of water-bourne parasitic diseases are likely to change. Secondly, the predicted increased frequency of extreme weather events may affect the magnitude and severity of disease outbreaks. For example, if winters in subtropical regions become warmer as predicted, parasites may now survive the winter, making the disease yearround rather than seasonal. Social drivers also have the potential to shape the future development of water-bourne diseases. As regions become drier, human interference such as dam construction, irrigation, reservoirs and canals may drive the distribution patterns of these diseases. Anticipated human migration from arid to wetter regions where water is available may also increase the transmission of these diseases. All such factors need to be considered when attempting to mitigate the effects of climate change on the distribution of infectious diseases. Health authorities around the country are aware of these problems and continue to monitor the potential spread of these diseases, as well providing better and more extensive primary health care – but much still remains to be done. ❑ Kirsty Robinson, Jessica Kavonic and Mischa Minne are registered for an MSc degree by course-work plus thesis at UCT (2012) within the African Climate and Development Initiative (ACDI). The article was submitted as part of their coursework within a climate change and freshwater module delivered and supervised by Drs John Bolton, Cecile Reed and Mike Lucas – of the Botany (JB) and Zoology (CR, MIL) Departments respectively.
Q ASSAF News ASSAf recognises South African scientists
The Academy of Science of South Africa (ASSAf) recognised top South African scientists at its prestigious annual awards ceremony held in Pretoria recently. ASSAf annually awards up to two ASSAf Science-for-Society Gold Medals for outstanding achievement in scientific thinking for the benefit of society. This year two awardees were selected. Jill Adler is the First Rand Foundation-National Research Foundation Chair of Mathematics Education at the University of the Witwatersrand, as well as the Chair of Mathematics Education at Kings College, London. Two young scientists were also recognised at the annual awards ceremony and presented with prestigious AU-TWAS prizes. The AU-TWAS award scheme aims to recognise and award talented young scientists in Africa. The prize in life and earth sciences
was awarded to Prof Alta Schutte from the North-West University and Prof Thokozani Majozi from the University of Pretoria received the prize for basic science, technology and innovation. 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 Commission (AUC), the Academy of Sciences for the Developing World (TWAS) and the Department of Science and Technology (DST). Through this award, the AU and TWAS jointly recognise and award an outstanding scientist in South Africa. The recipient should be under the age of forty, living and working in South Africa, and have a record of research publications in internationally recognised science journals. The award pertains to the science fields of Life and Earth Sciences; and Basic Science, Technology and Innovation.
Professor Thokozani Majozi with Phil Mjwara. Image: ASSAf
Professor Alta Schutte with Phil Mjwara. Image: ASSAf
Laerskool Lynnwood wins nail-biting finals of the 2012 AstroQuiz Ten teams of young learners from around South Africa met on Friday morning, 26 October 2012 in Centurion to battle it out in the eighth round of the Astronomy Quiz finals. The finals were hosted, funded and coordinated by the South African Agency for Science and Technology Advancement (SAASTA), a business unit of the National Research Foundation. The overall winner was Laerskool Lynnwood, a Gauteng team from Pretoria who had to compete in four grueling eliminating rounds at the SciBono Discovery Centre in Johannesburg before they clinched the big prize at the national finals. The team won an 20-cm mounted telescope with accessories for their school, laptop computers and trophies for each member. In the second place was Brebner Primary School in the Free State and third was Kimberley Junior School from the Northern Cape. Since the first-ever competition in 2005 at the Sci-Bono Discovery Centre in Johannesburg, the annual Astronomy Quiz has become a favourite on the school science calendar, with more than 3 200 learners from 817 schools participating in 2012. The teams of grade seven learners competed in four eliminating rounds of
the competition at 10 centres across South Africa: Hartebeesthoek Radio Astronomy Observatory (HartRAO) and SciBono Discovery Centre in Gauteng; Boyden Science Centre in the Free State; the South African Astronomical Observatory (SAAO) in the Western Cape and the Southern African Large Telescope (SALT) in the Northern Cape, Unizul Science Centre in KwaZulu-Natal, Mondi Science Centre in Mpumalanga, North West University’s Mafikeng Science Centre in North West, the University of Limpopo’s Science Centre and the Grahamstown Foundation (SciFest Africa) in the Eastern Cape. The finalists in the AstroQuiz 2012 competition were: HartRAO: AB Xuma Primary School (Gauteng). Boyden Observatory: Brebner Primary School (Free State). Unizul Science Centre: Mthunzini Primary School (KwaZuluNatal) .North West Science Centre: Maggie’s Millenium Primary School (North West Province). Mondi Science Centre: Diepgezet Primary School (Mpumalanga). SALT: Kimberley Junior School (Northern Cape). SAAO: Observatory Junior School (Western Cape). SciBono: Laerskool Lynnwood (Gauteng). Universityof Limpopo Science Centre: Bashasha Primary School (Limpopo). SciFest Africa: Graeme College (Eastern Cape).
Q SAASTA News
The winners of the 2012 AstroQuiz for grade seven learners are, from the left, Hans-Peter Fechter, IngeMari Alberts, Zahn Rijnen and Chris-Jasper Jooste from Laerskool Lynnwood in Pretoria. They won several prizes such as trophies, laptop computers and a telescope for their school in this competition, organised by the South African Agency for Science and Technology Advancement. Image: SAASTA
Quest 8(4) 2012 47
Laser technology illuminates stem cell research Thulile Khanyile and Patience Mthunzi explain the use of lasers in stem cell research
magine a world where organ donation and transplantation were no longer necessary, a time when cells (building blocks of different living organisms) from a patient’s own body were used to cure organ dysfunction and failure. Stem cells could be the key to unlocking this dream. These cells are able to evolve into any type of the body’s cells such as kidney, liver, brain, heart, blood – you name it and you got it. As shown in Figure 1, cells are small and the human body is made up of more than 200 different cell types. Some examples of these cells shown in Figure 2 include: connective tissue cells (e.g. bone cells), muscle cells, neurons (brain cells), photoreceptor cells in the form of rods and cones (assist in vision), sperm and blood cells. Although very, very tiny, cells are very complex systems. They divide and multiply in a process called mitosis. But there are parts of the body where the cells do not renew themselves regularly. Neurons are one example. The human brain contains anything between 80 – 120 billion neurons, but damaged brain tissue cannot be renewed. Another non-renewing type of cells is found in the articular cartilage that forms the lining of joints. This cartilage prevents friction in joints between bones. Damage of the articular cartilage can lead to a degenerative condition called osteoarthritis, causing severe pain. Stem cell research could revolutionise the treatment of diseases such as arthritis and improve the outcome for people who have suffered brain damage.
Different types of stem cells
There are two types of stem cells, those that come from the embryo (a very early stage of development) called embryonic stem cells (ES) and adult stem (AS) cells.
48 Quest 8(4) 2012
Figure 1: A diagram showing where cells, tissue, organs and organ systems fit within the nanometres (10-9 or 0.000,000,001) to metres (1m = 100 cm) scale
Figure 2. The different types of cells that are found in the human body.
ES cells, also called pluripotent stem cells, are able to make a variety of adult body cells. The word pluripotent comes from the Latin words plurimus – very many, and potens – having power.
For this reason, researchers are particularly interested in ES cells as a novel source for regenerative
medicine, where cells are used as therapy. However, the function of AS cells, particularly those derived from the bone marrow, is mainly to repair damaged tissue. As a result AS cells act as the body’s natural repair system, replenishing specific cells. They do not necessarily divide to create new tissue cells as ES cells do. This means that ES cells are particularly important for tissue and/or organ engineering, as
Q Laser technology
Figure 4. During optical transfection, small holes are created using laser irradiation to disrupt the cell membrane so that genes can be taken up by the cell.
Figure 3: Cells taken from the adult human skin can be used to make ES cells which in return can be made into new tissue cells that can be applied as a therapy for organ dysfunction and/or organ failure.
well as cell-based therapies. Recent research has shown that specific cells (skin, hair, tooth, etc) can be made back into ES cells (Figure 3). These are called induced pluripont stem cells (iPSCs) and these cells have exactly the same qualities and are able to create new tissue in the same way that the original ES cells do. An added benefit is that these cells can be made directly from abundant, continuously dividing and multiplying skin cells. It is these iPSCs that may form the basis of a new line of research that could lead to the possibility of regenerating failing organs. This would mean that people with diseased kidneys and livers would no longer need transplants, with all the problems of waiting for donors and organ rejection. Specific cells from either ES cells or iPSCs can be successfully produced by manipulating their genetic make-up. This can be achieved by introducing genes (short pieces of DNA) into the cells using a process called as cellular transfection. In this process genes are inserted into cells to make new cells. Before laser assisted cellular transfection was developed, invasive cell transfection techniques used liposomes, which could be taken up by the target cell and could cause damage. Now, CSIR’s National Laser Centre has developed a technique called photo-transfection, which is a non-
invasive methodology for efficiently transfecting stem cells. What is photo-transfection?
Photo-transfection or optical transfection is a simple ‘point and shoot’ chemicalfree method of genetically manipulating cells. Extremely small holes are drilled on the cell’s membrane (or outer skin) using pulsed femtosecond (fs, 10-15) lasers to introduce genes into stem cells. The photo-transfection cell sample chamber is shown in Figure 4. A pulsed laser is used to irradiate or ablate a cell membrane in solution, melting it down so that the genes, which are contained in liquid medium to enter the cell. One of the beauties of using laser technology for transfection is their ability to retain cell viability. Following laser treatment, the small holes induced on the cell membranes surface can self-heal (fig. 5) allowing the cells to continue growing, diving and multiplying in a healthy way. The monochromatic (one wavelength or colour) nature of laser beams, as well as their ability to focus into ultra small spot sizes puts laser technology at the forefront of such novel research techniques. Stem cells are known to be among the most difficult cells to transfect, but lasers have overcome many of the difficulties. Scientists in the biophotonics group at CSIR are now able to use laser light
Figure 5. Following laser ablation, the cell membrane buffering system takes control by naturally proving cell membrane building material, which very quickly covers the perforated location leaving cells intact and alive.
to ‘punch small holes into living stem cells’ to deliver a wealth of other micromaterials, such as therapeutic agents, like drugs and proteins. Another example of the use of this process is cellular inclusion of biological dyes, which mark certain cell components in living cells and allow intricate studies of both cellular function and diseases. Additional advantages are that photo-transfection setups can be easily integrated with other optical techniques such as confocal laser scanning microscopy and optical tweezer systems. ❑ Thulile Khanyile is currently working towards a Masters degree in the field of Biophotonics, with the National Laser Centre (CSIR). Dr Patience Mthunzi is a a senior scientist researcher at the NLC in the Biophotonics group, leading single cell and/ or molecule projects.
Quest 8(4) 2012 49
Unassuming plants Restios of the Fynbos. By Els Dorrat-Haaksma and H Peter Linder. (Cape Town. Struik Nature. 2012.) Restios are the southern hemisphere equivalent of sedges, which are a moorland plant in the northern hemisphere. Having spent a large part of my life in the nothern hemisphere I got to know its botany pretty well and always loved the moorland vegetation, and the sedges in particular. Restios hold the same fascination for me. I have several in my garden and am looking forward to more after an extensive landscaping exercise. Restios are unassuming plants. They do not have spectacular flowers or attract colourful birds or insects. But they are quite lovely plants, nonetheless. The presence of the family Restionaceae is a unique distinguishing feature of the fynbos kingdom. They are also found in small patches of the Rift Valley and Madagascar, coastal strips of Australia, the whole of Tasmania and New Zealand and in parts of the southern areas of Chile in South America. Restios are a family of perennial, evergreen, grass-like plants, ranging from 10 cm to 3 m in height. This is a southern or ‘austral’ plant species, with around 357 species in Africa, 150 species in Australia, four species in New Zealand and a single species in South America. There is also a single, widespread species in South East Asia. But it is only in the Cape Floral Kingdom that the restios dominate vegetation over large areas. This makes it an important species and this book looks at the family in detail, covering the ecology of the family, its biology – it is wind pollinated and dispersed by fynbos insects and mammals – and its importance to the people who live in its area of distribution. Restios have been used as building materials for many centuries and are now commonly used for thatching. The identification guides are simple and easy to use, with clear photographs of the plants and their various features. There is also a section on growing restios, with useful tips on planting and growing the species. The book is compact enough to fit into a backpack and will also be used by keen water-wise gardeners. The starry skies 2013 Sky Guide: Africa South: Astronomical Handbook for Southern Africa. Astronomical Society of Southern Africa. (Cape Town. Struik Nature. 2012.) You know the end of the year is close when this little annual handbook is published. This is the indispensible guide to the night skies in southern Africa and all keen
50 Quest 8(4) 2012
astronomers, amateur and otherwise, will have a copy. There are clear instructions on how to use the guide, which is quite technical, but not beyond the reach of anyone interested in the skies above us. The year’s highlights are detailed early, so that you know what to look out for on particular dates. Each month has an almanac, details about the constellations, the planets and the moon, as well as further information on any highlights for that particular time. For the newcomer there is a section on basic observing skills and what to look for when buying a telescope, as well as a listing of observatories and a useful glossary of terms. The songs of the stars Searching African Skies: The Square Kilometre Array and South Africa’s quest to hear the songs of the stars. By Sarah Wild. (Aukland Park. Jacana Media. 2012.) Sarah Wild is the Science and Technology editor at Business Day and is an award-winning science journalist. Her enthusiasm and love for her subject come through strongly in this exciting book. The Square Kilometre Array is arguably the most exciting and important scientific development ever in Africa. Searching African Skies tells the story of radio astronomy in South Africa – from the first telescopes built by NASA in the 1960s to our challenge to Australia – one of radio astronomy’s world leaders. What exactly is the Square Kilometre Array (SKA)? How did South Africa manage to bid against Australia to host the largest scientific instrument on Earth? What will the SKA tell us about our universe? How far will we be able to see back in time with the SKA? This book answers all these questions, interspersed with |Xam Bushmen stories and Xhosa starlore. This is a wonderful journey through one of the most exciting scientific endeavours of our time, a must for anyone who is enthusiastic about the science of astronomy.
Q Books Towering forests Trees of the Garden Route: Mossel Bay to Storms River. By Elna Venter. (Pretoria. Briza Press. 2012.) This is the second edition of this remarkable book. The author, Elna Venter, sadly died shortly before the book went to press. Trees of the Garden Route is an accessible identification manual written to the hightest professional standards. Elna Venter was an amateur botanist, whose training was in mathematics. She worked as a metereological assistant in a university agricultural faculty. Her lifelong interest in botany was sparked when her daughter was studying veterinary science at Onderstepoort and it became evident that there was a need for updated study material on poisonous plants. Venter put together a powerful multimedia educational tool using Powerpoint, spending months travelling South Africa with her camera to produce a CD-ROM on plants that were poisonous to livestock. She has brought that same attention to detail to this excellent little book on the wonderful trees that characterise the Garden Route. The tree key – based on the definition of a leaf – is masterful and should be an excellent start to identifying trees when out walking, leading you cleverly through some difficult identification concepts to the species of tree that you are looking at. Each species is illustrated with photographs of the whole tree, the bark, the leaves, the flowers and the fruits. There is an explanation of the source of the scientific name and a distribution map for each species. There is also a short paragraph with each species on which animals eat the leaves and/or the fruit and any medicinal or other applications of the plant. The book contains information about 110 trees and has 1 800 colour photographs, making it one of the easiest tree identification books on the market. Water-wise and creative Creative Gardening with Indigenous Plants: A South African Guide. By Pitta Joffe and Tinus Oberholzer. (Pretoria, Briza Press. 2012.) The idea of gardening with plants indigenous to your particular area of South Africa is spreading. We are a water-poor country and it makes sense to use what grows naturally in an area for the best possible display in a garden. This book helps you to do
that, wherever you live. The book starts with an excellent section on soils, soil types and how to nurture your garden’s soil. This includes live pest control – using biological control rather than chemicals and using mulch as a way of preventing evaporation and protecting the soil. Readers are encouraged to make the most of the natural fauna that inhabits the garden and not regard these animals as pests. Each of the seven biomes across the country is described as a garden biome, setting the scene for the use of indigenous plants. There is a page on each biome and how to make sure that you have the correct type of soil for the plants that you want to grow. The authors also describe how to plan your garden to attract birds and butterflies. There is a useful section on propagating plants from seeds and from cuttings. The book is then divided into the different groups – trees, shrubs, accent plants, climbers and so on. This book will help any aspiring or established gardener make a wonderful, sustainable indigenous garden, wherever you are in the country. Exploring the seas Southern African Sea Life: A Guide for Young Explorers. By Sophie von der Heyden. Photography by Guido Zsilavecz. (Cape Town. Struik Nature. 2010.) Sophie von der Heyden is a lecturer in marine biology, conservation and genetics at Stellenbosch University. She decided to write this book for her children and I am sure it will inspire many more generations of marine biologists. This is a book for children – but will be loved by people of all ages. The book covers our ocean currents and the importance of our marine ecosystems. It is split up into the different marine habitats – rocky shores, sandy beaches, kelp forests, estuaries and coral reefs. The marine plants and animals are split up into the different taxonomic groups, giving a good introduction to each phylum. The southern African coastline is examined in detail – from the Namibian coast to southern Mozambique – drawing on the information in the previous sections to pull together the experience of exploring the sea shore. Lavishly illustrated by Guido Zsilavecz’s photographs, this book will be taken on any holiday to the coast and would be useful to have when teaching Natural Science to younger children.
Quest 8(4) 2012 51
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52 Quest 8(3) 2012
Q Back page science Spot the space station over your backyard with new NASA service On the 12th anniversary of crews continuously living and working aboard the International Space Station, NASA announced a new service to help people see the orbiting laboratory when it passes overhead. ‘Spot the station’ will send an email or text message to those who sign up for the service a few hours before they will be able to see the space station. When the space station is visible – typically at dawn and dusk – it is the brightest object in the night sky, other than the moon. On a clear night, the station is visible as a fast moving point of light, similar in size and brightness to the planet Venus. ‘Spot the station’ users will have the option to receive alerts about morning, evening or both types of sightings. To sign up for ‘Spot the Station,’ visit: http:// spotthestation.nasa.gov
makes adhesive discs with weak attachments, that snap away from the ground and leave prey suspended in the air. By the way, a spider only makes one kind of glue – how does it work for both applications? The researchers believe that these two degrees of adhesion have nothing to do with the chemical makeup of the glue, but rather the spinning behaviours of the spider. They're studying this key natural design principle to see if we can emulate it in beneficial applications. Everything from industrial-strength tape to adhesives strong enough to bind sutures to heal a fractured shoulder yet delicate enough for 'ouch-free' bandages. Who ever thought we'd be learning web apps from a spider?
A spider’s web. The International Space Station – now much easier to spot. Image: NASA
One glue that sticks in two different ways University of Akron biologists and polymer scientists aren't scared of spiders – they're intrigued and even inspired by them. In particular, a trait they discovered that spiders demonstrate when creating webs. You might call it 'spidey sense'. If you're a spider, you have two different kinds of prey: flying meals and crawling ones. So you can employ two different strategies with your web. To catch insects flying at high velocity, the spider creates super sticky adhesive disks, which firmly anchor webs to ceilings and vertical surfaces. To nab those ground-bound bugs, it
Image: pdphoto.org, via Wikimedia Commons)
Feeding the cellphone frenzy Our cute little smartphones and tablets are datahungry little monsters. In the next five years, wireless demand could be 18 times greater. Carriers are scrambling to build more wireless base stations and buy rights to more frequencies, but there may be a better way. New technology being developed by Rice University, Bell Labs and Yale has already shown that it could increase existing network capacity by more than six times. The key is the more antennas you have the more users you can serve. Rice graduate student Clayton Shepard built the 64-antenna working prototype: 'Argos'. ‘Essentially what we're doing is we're sending a physical beam so it's like using all of these antennas to create a very, very directional antenna focused only on the user that you want to send data to. And we can do this
simultaneously to many users – so by creating each of these narrow beams we can send to each user without interfering with the other users and this gives us a huge capacity gain,’ he says. It will be a while before this technology is commercially available, ‘but it certainly has a great potential of solving the bandwidth crunch for cellular networks in the next five or ten years.’
Breast cancer and body rhythms Could working the night shift alter a woman's body clock enough to cause breast cancer? Virginia Tech molecular biologist Carla Finkielstein says, ‘There are a number of epidemiological studies that show women working night shifts have a higher incidence of breast cancer’. Finkielstein is studying this question microscopically, one cell at a time. She wants to know the impact of night-shift work on a woman's physiology. Can working odd hours actually alter a woman’s body chemistry – turning healthy cells into cancer cells? ‘What we're trying to understand is how changes in environmental conditions influence the expression of genes that regulate cell division,’ explains Finkielstein. Finkielstein uses frog embryos to help figure out on a molecular basis the physiological changes in women who work the night shift. She says studies show that working ‘night owls’ have abnormal levels of specific proteins in their cells, which act by turning on and off genes that regulate how cells grow and divide. Finkielstein injects some of the molecules into frog cells to study their effects. ‘... and that could end up in cancer,’ she explains. ‘It could end up in very many other diseases. But in our studies we believe that it ends up in an abnormal proliferation of cells.’ Source: National Science Foundation
A mammogram showing a tumour. Image: Wikimedia Commons
MIND-BOGGLING MATHS PUZZLE FOR Q uest READERS Q uest Maths Puzzle no. 23 Starting in the bottom left corner and moving either up or right, adding up the numbers along the way, what is the largest sum which can be made?
Answer to Maths Puzzle no. 22: Solution 2 + 5 = 46 this simplifies to 23 6 8 48 24
Win a prize! Send us your answer (fax, e-mail or snail-mail) together with your name and contact details by 15:00 on Friday, 8 February 2013. The first correct entry that we open will be the lucky winner. We’ll send you a cool Truly Scientific calculator! Mark your answer ‘Quest Maths Puzzle no. 23’ and send it to: Quest Maths Puzzle, Living Maths, P.O. Box 195, Bergvliet, 7864, Cape Town, South Africa. Fax: 0866 710 953. E-mail: firstname.lastname@example.org. For more on Living Maths, phone (083) 308 3883 and visit www.livingmaths.com.
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kids love chemistry Getting the next generations excited about chemistry is important for humankind’s future. That’s why we’ve created “Kids’ Lab” in 15 countries, where the young ones can learn about chemistry and science in a fun, hands-on way. Little students and test tubes finally getting along? At BASF, we create chemistry. www.basf.com/chemistry www.basf.co.za Tel: +27 11 203 2400
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