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Education system sets learners up for failure

- Wits University

Companies see matric certificates as applicant’s ability to read, write and be trained, research shows.

The South African education system is setting up whole generations of school-leavers to fail by poorly equipping them to study in a second language.

Volker Schöer, a statistical economist in the Wits School of Economics and Business Sciences, is currently studying how the labour market selects candidates from masses of unschooled job-seekers in the country.

“If we think that education is supposed to allow access to the labour market and that education influences what employers think about candidates and how jobs are allocated, then we need to understand more about how firms select candidates, how they use social networks to select and what they require,” says Schöer.

Schöer found that whether a person has one year of education or 11 years, they are seen in completely the same light if they don’t have a matric certificate.

“Companies see it that a matric certificate shows that a person can read and write and can be trained but that a person without it stands no chance,” says Schöer.

In his efforts to study the shortfalls of the education system, Schöer teamed up with Prof. Brahm Fleisch from the Wits School of Education and tested first -year students at Wits on both their mathematical and language abilities.

“There was a massive difference between English first language students and those who use it as a second language. In maths, students who used English as a second language also had a problem.

“They were very good with procedural problems but struggled when they needed to take a problem one step further,” he elaborates.

Schöer and Fleisch also tested around 2 500 grade four pupils from 100 average performing schools, according to the Annual National Assessments (ANA), to test their English language competencies as second language speakers, with the hope of introducing an educational intervention in that grade to fix the problem.

While children at these schools were just as eager to learn and please their teachers as in schools with better resources, the results were horrifying. Out of a total of 51 marks in an English language assessment which tests language competencies that the learners are supposed to have learned during the foundation phase (grade 1 to grade 3), the average mark of the grade four learners was nine marks, which was less than 20%.

“We found they are too far behind,” he says. “All the disadvantages start at grade one and build up throughout the schooling career. Our intervention was too weak to address these shortfalls in grade four. You have to start at grade one.”

The further learners advance in their schooling careers, the wider the gap becomes and by the time they leave school, companies are not interested in employing them.

“Right from the beginning, they are set up for failure and it is passed on year after year,” explains Schöer.

“The gap doesn’t shrink. It increases. Giving matric won’t solve the skills mismatch.  We need to see how we can improve the education system.”

Following this research, Fleisch has already set up an intervention programme with some of the worst performing schools in Gauteng. The North West Department of Education has implemented a similar programme and Limpopo will start an intervention programme next year.

Reducing wear and tear makes maintenance easier and cheaper

- Wits University

Professor Natasha Sacks aims to make Wits a world expert in tribology.

Sacks, Head of the Carbides and Cermets focus area in the DST-NRF Centre of Excellence in Strong Materials at Wits, spends her days studying hard metals and explores how to reduce the wear and tear on material surfaces.

She is an expert in tribology – a field that looks at how to reduce the wear of and friction on materials. She has successfully collaborated with local tools manufacturer, Pilot Tools, to improve the recycling of wear-resistant tungsten carbide metals. This is a mutually beneficial relationship that paves the way for greater partnerships with industry in the future.

“My lifelong interest has been in what makes a particular material function in a certain manner,” explains Sacks, the recipient of the Louw Alberts award from the South African Institute of Tribology. “Tribology is a large field in the rest of the world but in South Africa people are only now realising that by reducing wear and friction, you can make maintenance easier and therefore cheaper.”

Sacks’ two main research interests – tungsten carbide and tribology – fit together like a hand in a glove. Tungsten carbide is a wear resistant material, which may also be used to coat softer materials, while tribology is the science behind limiting wear.

“Tribology could be as simple as changing the angle of the tool on the surface during machining,” says Sacks. “However, it is also a highly complex science, involving the various materials, lubricants and additives and it makes up a major part of the operations in both the manufacturing and mining industries.”

Sacks serves on the editorial board of the International Journal of Refractory Metals and Hard Materials and served as a session chairperson at the International Conference on the Science of Hard Materials in 2014.

Her aim is to make Wits a world expert in tribology and to expand both the consulting and education capabilities of the Laboratory.

“I also want to expand our expertise in materials to energy and biomaterials and include tests on hip and knee joints,” she concludes.

How do South African companies report on sustainability?

- Wits University

Warren Maroun examines how companies are reporting on different sustainability metrics in their integrated reports.

Maroun, a Professor in the Wits School of Accountancy, recently started research into the corporate reporting by JSE-listed companies, including how they communicate the impact of serious environmental and social issues to their stakeholders.

While South Africa is seen as a world leader in terms of integrated reporting, companies fall short of linking the impacts of their social, human, manufacturing and environmental capital in their reporting, mainly due to a lack of knowledge of how this should be done.

“If you think about accounting, the first thing you think about is income statements and balance sheets. How do you take non-financial issues like the extinction of species, global warming and social unrest into account?

How do you work out what their cost to the company is? How do you report that information in your annual integrated report?” he asks.

“What companies are supposed to do is to give you a very complete picture of how they create value.”

A good integrated report includes traditional financial performance but must also take into account environmental, social and ethical considerations. This is something which companies are struggling to achieve.

“A traditional accounting system is rand and cents focused.  We measure everything in terms of rand value. Now we have to take into account these important performance issues and it is very difficult or almost impossible to quantify them,” he says.

As an example, he asks how a mining company explains to investors the cost of improving the accommodation of mine workers so that they do not have a Marikana-type incident. How do they measure how satisfied the employees are with the reforms that they have introduced? How do they communicate the impact that the reforms have had on their financial returns and how do they understand and quantify the improvement in efficiency in operations in their manufactured capital as a result?

“A truly good integrated report is able to explain links between different types of capital - financial, manufacturing, social, human and environmental capital. It describes the relationship between these types of capital and quantifies the relationship,” says Maroun.

“The companies are able to identify the capital and they are able to describe the relationship but the actual interconnection and the quantification of the relationship between the capital is extremely difficult to achieve.”

While he is only seven months into the project, Maroun is confident that he will be able to come up with some answers.

However, the deeper he gets into the research, the more questions arise.  Maroun is a Chartered Accountant and a Wits lecturer.  He holds a PhD from Kings College, London.

Optimisation production through process engineering

- Wits University

Researchers say there are still large gaps in our understanding of the associated utility systems in batch chemical processes.

Professor Thokozani Majozi holds the DST-NRF Chair in Sustainable Process Engineering at Wits.

“Our main research area is sustainable process engineering, within which we are addressing two broad areas - batch chemical processes and continuous processes,” explains Majozi, who’s PhD from the University of Manchester’s Institute of Science and Technology focused on the optimisation of multipurpose batch chemical processes.

More than 50% of South African chemical processes fall within the batch processing type. Ironically, none of the engineering undergraduate programmes in the country focus on this category of chemical processes.

In addition to handling time effectively, which is fundamental in the design and synthesis of batch plants, Majozi realised that there are still large gaps in our understanding of the associated utility systems in batch chemical processes.

These include water and energy.

“In general, batch processes use and generate smaller amounts of water and wastewater, respectively,” he explains.

“However, the nature of industries in which they are generally encountered, like pharmaceuticals and agrochemicals, suggest that they have higher toxic levels in comparison to their continuous counterparts. Consequently, there is a need to develop dedicated techniques to optimise water use.”

On continuous processes, Majozi’s group has been focusing on debottlenecking utility systems, with emphasis on steam system networks and cooling water systems.

“Our approach is to look at the cooling tower and heat exchanger network as one unit because they work together and cannot be improved in isolation.”

“If you look at them together, all the evidence suggests you will ultimately get a better system,” he says. “We are also looking at power stations because one of the key units of operation is the cooling tower. 

After you have produced superheated steam to run your turbines, the steam is condensed back into water that is then recycled back into the boiler and supplemented by the makeup stream.”

The condensation step is extremely important for the efficiency of the system and the design of the cooling tower is fundamental. Majozi and his team are also exploring the overall efficiency of power generation facilities, including renewable energy options.

His team also focuses on Clean Coal Technology and how to optimise complex power generation systems to achieve maximum efficiencies. On the batch processes side, Majozi is addressing industry production efficiencies.

“The challenge is to help industry use their available capital optimally to meet their production targets for a range of products with different equipment requirements. This requires careful scheduling to meet the prescribed targets within prescribed time horizons,” he concludes.

Using gene therapy to combat HBV infection

- Wits University

Hepatitis B Virus causes between 600 000 and one million deaths per year, predominantly in sub-Saharan Africa and Asia.

Dr Buhle Moyo, a postdoctoral research fellow in the Department of Molecular Haematology at Wits, is working towards the development of safe and effective gene therapeutics against the Hepatitis B Virus (HBV).

Moyo joined the Antiviral Gene Therapy Research Unit (AGTRU) in 2013 and her research focuses on using a re-engineered virus to deliver a therapeutic gene to the liver, the site of HBV infection.

HBV causes liver cancer and cirrhosis and causes between 600 000 and one million deaths per year, predominantly in sub-Saharan Africa and Asia.

Gene therapy technologies offer potential solutions for the effective management of intractable diseases and intensive research activities are underway to apply these technologies to HBV infection.

The AGTRU has developed a number of highly efficacious gene therapeutics capable of interfering with the life cycle of HBV. However, the biggest hurdle facing implementation of gene therapeutics in a clinical setting is the lack of an effective means of delivering the therapy to the target organ.”

The problem was that we needed to find a system to deliver the gene therapy safely and efficiently,” says Moyo.

“We’ve been working with using Adeno-Associated Viruses (AAVs) as a vector and we were able to re-engineer it successfully.”

AAVs are small viruses that infect humans. They are not known to cause disease and they are able to efficiently deliver their cargo and are easy to re-engineer. As a consequence, AAVs are commonly used in the field of gene therapy.

The AGTRU recently described the successful adaptation of a novel technology, Transcription Activator-Like Effector Nucleases (TALENs), to disable HBV.

The work was published in Molecular Therapy, the official journal of the American Society of Gene and Cell Therapy, in 2013. These TALENs were engineered to bind and cut HBV DNA. Subsequent introduction of mutations at the cut site effectively disables the virus.

Moyo and the AGTRU team found AAVs are efficient vectors to carry the TALE-based therapies to the livers of mice.

The team is currently engaged in pre-clinical studies in mice to assess the efficacy of the delivery system and the gene therapeutics.

“We were able to show very effective delivery of the TALENs and have very promising results.  We are hoping to publish the results in a high-impact journal before the end of the year,” says Moyo.

Understanding the slave trade on the Loango Coast

- Wits University

More than one million slaves were traded during 18th Century on the Loango coastline.

Dr Stacey Sommerdyk, a Canadian postdoctoral fellow in the Wits History Department, is happy to give anyone who is willing to listen, a lesson on the history of the transatlantic slave trade of the 18th Century.

Sommerdyk, who comes from the Great Lakes area in Canada, completed her PhD on the Trade and Merchant Community of the Loango Coast in the 18th Century at Hull University in the United Kingdom before moving to Johannesburg to continue her research.

More than one million slaves were traded during the period on the Loango coastline, which is now split between the Angolan Province of Cabinda and the Democratic Republic of the Congo.

Sommerdyk is currently undertaking a careful examination of the records of the Dutch Middelburg Commercial Company (MCC) to identify the African slave traders on the Loango coast.

Working through the transaction records of 10 000 slaves that were sold to the MCC, Sommerdyk has identified 640 African slave traders who operated in the area during the 18th Century and early 19th Century.

These slaves were transported across the Atlantic on 32 voyages to be sold in the slave trade in the Americas. Among them were three pregnant women who all gave birth during the crossing. All three women and their children survived.

In studying the records, Sommerdyk found that the political leaders of the time were not active in the slave trade. Instead, they appointed a person to regulate the trade on their behalf.

This person, with the title “Mafouk”, not only regulated the trading but did the bidding, negotiations and selling and also took a cut from each transaction. In the end, the Mafouk became one of the most powerful men in the community, often overshadowing the political head.

“So, the question that arises is why did the political head not take part in the trading? By appointing someone to do it on his behalf, he actively undermined himself,” says Sommerdyk.

The government structures were centralised at the time so the political head could stop trading at any time but they rarely did.

“Another question that arises is whether religion was a reason for the political leader not taking part in trading,” she says.

Sommerdyk says the Congolese government is currently in negotiations with the United Nations Educational, Scientific and Cultural Organization, in order to get historic recognition for some of the slave trading sites in the country.

Fibre has its limits too

- Wits University

Wits researchers in optical communications explore ways to drastically increase the optical fibre bandwidth.

Over the past five years, there has been a fivefold increase in internet traffic and this trend is expected to continue steadily, globally. Thus far, the demand for high bandwidth has been met by implementing optical fibre communication.

But soon the limit in the amount of data that can be communicated through fibres with current technologies will be reached. Research in the Structured Light group (School of Physics) at Wits, headed by Distinguished Professor Andrew Forbes, aims to explore ways to drastically increase the optical fibre bandwidth by utilising patterns of light.

Patterns have the ability to carry an infinite amount of information and presently represent a resource not used in optical communication

Bienvenu Ndagano is a Masters student trying to find novel ways to encode and transmit information through free space and optical fibres using patterns of light.

“I am looking at a property of light called orbital angular momentum, which causes light to twist.  The number of twists present in a beam of light can be counted and used to encode information in the same way a computer would count zeros and ones and translate them into bits of information,” explains Ndagano.

Together with his colleagues, he generates light with a twist by shaping a laser beam to give it a finite number of twists.

“We can either give it a single number of twists or multiple numbers of twists simultaneously. We send the shaped laser beam through an optical fibre and we analyse the output by counting the number of measured twists and comparing it to the number of twists generated at the input.”

Thus far Ndagano can measure the number of twists at the output with high fidelity when compared to the input.

“We applied our technique to send pictures through an optical fibre. By associating the colour of each pixel on a picture to a twist number, we were able to transform a picture into sequences of twisted light beams that were sent through the fibre and transformed back to pixels to recreate the picture.

Recently the group have demonstrated a free space, fibre, free space link using this twisted light.  The work, done in the Wits laboratory in collaboration with researchers from the University of Jena (Germany), was selected as a highlighted paper by the Journal of Optics (UK).  The work also won numerous student awards for Ndagano, most recently at the international conference of SPIE, Photonics West, in San Francisco (USA).

Gleeble to the rescue

- Wits University

Now Dr Lesley Chown can test new metals cost-effectively in her lab.

A Senior Lecturer in the Wits School of Chemical and Metallurgical Engineering, Chown received the R13.5-million-Gleeble thanks to funding from the National Research Foundation and the University.

A Gleeble is a computerised simulator in which various performance parameters – such as strength, breaking point and heat qualities – of a specific material are measured.

Chown has a special interest in the structure and property relationships in metallic alloys and the continuous casting processes of metals.

The production testing and development of new metals and alloys are usually highly complex and expensive processes but a system like the Gleeble allows these processes to be tested in a cost-effective way in the laboratory.

A sample of material is heated and mechanically worked while various performance parameters of interest are measured and recorded for later analysis. After the simulation is done, the microstructure of the material may also be examined.

“You can realistically simulate large- scale industrial changes and you can use combinations of different heating and cooling cycles to simulate processes like the hot-rolling of steel,” explains Chown.

She works with Professor Lesley Cornish, Director of the DST-NRF Centre in Strong Materials at Wits, and Professor Tony Paterson, the Chair of Welding funded by the South African Institute of Welding.

Chown and her team will be using the Gleeble in collaboration with other academic institutions like the CSIR, industry partners and will develop human capital by training new students.

“We will also be supporting industry in process optimisation in thermo-mechanical processes and we will be roping in more postgraduate students. This will be a win-win situation for us and for the industry,” she adds.

Chown also has her heart set on blue sky research, where she will be experimenting with various titanium alloys to produce cheaper titanium alloys for land-based use.

She started her career at Iscor before moving to Mintek and then Wits. She has more than 15 years of experience working on an older version of the Gleeble.

Children should learn in many languages

- Wits University

International Mother Tongue Day: Insisting that children use one language at a time is primary cause for inability to reason cognitively, research shows.

South Africa’s middleclass children are suffering from a national identity crisis because they are being taught in English while their mother tongue is being ignored.

Except for Afrikaans, which is taught throughout secondary school, children with other African languages as their home language only study their mother tongue language up until grade three, after which they continue their schooling career in English.

According to Professor Leketi Makalela, Head of the Division of Languages, Literacies and Literatures in the Wits School of Education, the insistence to teach children using one language at a time is the primary cause for why whole generations of South African children are not able to reason cognitively.

“Three years of learning an academic language can never be sufficient by any standard,” says Makalela. “We know that it takes six years for children to master the syntax of their home language.”

There is a connection between cognitive development and language and to teach a child in his mother tongue for three years and then change to English causes a lot of confusion. “There is no linguistic justification for this policy, except that it is inherited,” he adds.

Makalela obtained his PhD in English Studies, Literacy and Linguistics and he is the Editor-in-Chief of the ISI-listed Linguistics and Applied Language Studies Journal.

He believes that language is a tool that a person uses to access the world, and literacy is – and provides – the ability for a person ‘to know’ and ‘to be’. His research focuses on how we can use multilingualism as a resource, rather than it being a barrier.

“Our classrooms are very conservative and our teachers believe that there is only space for one language at a time in the classroom, but outside the classrooms children learn in a very fluid and versatile manner and communicate in a number of languages,” he explains.

By creating a division between a child’s home language and a second language, teachers are effectively halting a child’s ability to learn to reason.

“Grade nines at the moment learn by memorising, not reasoning and that is why they fall short at university. Universities require them to reason,” he adds.

Makalela believes that children should be taught in multiple languages and learn to reason with both their home language and English by doing subjects such as science and maths through to matric level. Makalela did edumetric tests at 15 schools to establish children’s reading abilities. He found their literacy performance was at least three years below their expected proficiencies.

“They were supposed to be able to understand at least 75% of what a person says,” he says. “They understood only 25%.”

Makalela believes the situation can be corrected by following the example of Canada, where children are taught in both English and French at the same time.

“The teaching of more than one language at a time does not create mental confusion in a child, as many teachers believe. It is possible to have more than one language in the classroom and for teachers to allow the use of more than one language more generally.”

Restoring pride in African people

- Wits University

Professor Christopher Henshilwood is the co-winner of the Vice-Chancellor’s research award.

Henshilwood currently holds a 15 year South Africa NRF-funded Research Chair and Distinguished Professorship within the DST-NRF Centre of Excellence for Palaeosciences at Wits, is A-rated by the National Research Foundation and is a Professor of African Prehistory in the Archaeology, History, Culture and Religion Institute at the University of Bergen, Norway.

“I believe the award was made because of the discoveries that my team and I have made over the past 20 years that have helped to restore pride in African people by demonstrating the principal role that Africa played in the evolution of our own species, Homo sapiens, a role that just two decades ago was accorded mostly to Europe,” says Henshilwood.

Since 1991, Henshilwood has directed excavations at Stone Age sites in South Africa. With his research team, he increasingly provides evidence for an African origin for behavioural and technological modernity associated with Homo sapiens from about 100 000 years ago and has decisively shown that Africa is the birthplace for the early development of modern human cognition.

“In sum, my work on early Homo sapiens’ cognitive abilities has frequently challenged mainframe views,” says Henshilwood.

“My discoveries, with my team, over the past four years of new archaeological sites located in the southern Cape will add significantly to existing knowledge of early Homo sapiens in southern Africa, especially in coastal environments.”

Henshilwood has published more than 60 papers in leading peer reviewed journals, volumes and books on aspects of African archaeology, especially the Middle and Later Stone Age; on the origins of language and symbolism; the effects of climatic variation on human demographics; and the epistemology of early behavioural evolution.

His research on the recognition of symbolic material culture among Middle Stone Age people and their ability for complex technology has enabled us to question the once dominant paradigm of a sudden European origin of human behavioural modernity. “A central achievement and focus of my many publications is recognising that the most ancient symbolic traditions in Africa date back at least 100 000 years,” he says.

For Henshilwood, excavating an archaeological site is like travelling in a time-machine.

“The deposits that were laid down up to 100 000 years ago in these sites by the direct ancestors of all of us, Homo sapiens, are still lying in the exact place in which they were put. It is a great privilege to painstakingly recover these deposits and to reconstruct, piece by piece, the daily lives of these ancient people,” he says.

Together with his intercontinental multi- and cross-disciplinary research teams in South Africa, Europe and the USA, Henshilwood says he will directly address some of the still unanswered questions about Homo sapiens in the next decade.

“Some of these questions include: when and why did humans first become ‘behaviourally modern’; did cognitive changes in the human brain accelerate behavioural variability; how were these groups of hunter gatherers socially organised; was social cohesion enhanced by the adoption of symbolic material culture; how adaptable were humans to environmental change and did climatic unpredictability act a driver for technological innovation and subsistence adaptations,” he says.

“Our research will focus explicitly on the period between 100 000 - 50 000 thousand years ago.”

No jaws of a nutcracker

- Wits University

Media release: Biting too hard would have dislocated the jaw of Australopithecus sediba.

South Africa’s Australopithecus sediba, discovered in 2008 at the renowned archaeological site of Malapa in the Cradle of Humankind World Heritage Site, is again helping us to study and understand the origins of humans.

Research published in 2012 garnered international attention by suggesting that this possible early human ancestor had lived on a diverse woodland diet including hard foods mixed in with tree bark, fruit, leaves and other plant products.

But new research by an international team of researchers, including Professors Lee Berger and Kristian Carlson from the Evolutionary Studies Institute (ESI) at the University of the Witwatersrand, now shows that Australopithecus sediba didn’t have the jaw and tooth structure necessary to exist on a steady diet of hard foods.

“Most australopiths had amazing adaptations in their jaws, teeth and faces that allowed them to process foods that were difficult to chew or crack open. Among other things, they were able to efficiently bite down on foods with very high forces,” says Professor David Strait, team leader and anthropologist from Washington University in St. Louis, US.

Adds co-author Dr Justin Ledogar, researcher at the University of New England in Australia: “Australopithecus sediba is thought by some researchers to lie near the ancestry of Homo, the group to which our species belongs yet we find that A. sediba had an important limitation on its ability to bite powerfully; if it had bitten as hard as possible on its molar teeth using the full force of its chewing muscles, it would have dislocated its jaw.”

The study – published today, 8 February 2016, in the journal Nature Communications – describes biomechanical testing of a computer-based model of an Australopithecus sediba skull.

The model is based on the fossil skull recovered by Berger’s team in 2008 from Malapa, a cave some 40kms west from Johannesburg, South Africa. The biomechanical methods used in the study are similar to those used by engineers to test whether or not planes, cars, machine parts or other mechanical devices are strong enough to avoid breaking during use.

“These unexpected, but clearly intriguing, findings of the study are substantiated by the team of scientists having spent over a decade conducting meticulous, thorough experimental research on chewing mechanics in order to validate this application of computer-assisted modelling,” Carlson, a Reader in the ESI says.

Berger, Carlson, and Professor Darryl de Ruiter (Texas A&M University, US) are some of the researchers who described A. sediba and are also authors on the biomechanical study.

Adds Carlson: “This collaborative research effort underscores the crucial scientific benefits that South African scientists enjoy as a result of the formal association between South Africa’s Department of Science and Technology and the European Synchrotron Radiation Facility (ESRF) in Grenoble, France.”

The fossilised skull of Australopithecus sediba specimen MH1 and a finite element model of its cranium depicting strains experienced during a simulated bite on its premolars. “Warm” colors indicate regions of high strain, while “cool” colors indicate regions of low strain. CREDIT: Image of MH1 by Brett Eloff provided courtesy of Lee Berger and the University of the Witwatersrand.

Caption: The fossilised skull of Australopithecus sediba specimen MH1 and a finite element model of its cranium depicting strains experienced during a simulated bite on its premolars. “Warm” colors indicate regions of high strain, while “cool” colors indicate regions of low strain. CREDIT: Image of MH1 by Brett Eloff provided courtesy of Lee Berger and the University of the Witwatersrand.

 

About Australopithecus sediba:

Australopithecus sediba, a diminutive pre-human species that lived about two million years ago in southern Africa, has been heralded as a possible ancestor or close relative of Homo.

Australopiths appear in the fossil record about four million years ago, and although they have some human traits such as the ability to walk upright on two legs, most of them lack other characteristically human features such as a large brain, flat faces with small jaws and teeth, and advanced tool-use.

Humans, members of the genus Homo, are almost certainly descended from an australopith ancestor, and A. sediba is a candidate to be either that ancestor or something similar to it.

About the new findings:

The new study does not directly address whether Australopithecus sediba is indeed a close evolutionary relative of early Homo, but it does provide further evidence that dietary changes were shaping the evolutionary paths of early humans.

“Humans also have this limitation on biting forcefully and we suspect that early Homo had it as well, yet the other australopiths that we have examined are not nearly as limited in this regard,” says Ledogar. “This means that whereas some australopith populations were evolving adaptations to maximize their ability to bite powerfully, others (including A. sediba) were evolving in the opposite direction.”

“Some of these ultimately gave rise to Homo,” adds Strait. “Thus, a key to understanding the origin of our genus is to realize that ecological factors must have disrupted the feeding behaviors and diets of australopiths. Diet is likely to have played a key role in the origin of Homo.”

Strait, a paleoanthropologist who has written about the ecological adaptations and evolutionary relationships of early humans, as well as the origin and evolution of bipedalism, said this study offers a good example of how the tools of engineering can be used to answer evolutionary questions. In this case, they help us to better understand what the facial skeleton can tell us about the diet and lifestyles of humans and other primates.

“Our study provides a really nice demonstration of the difference between reconstructing the behaviors of extinct animals and understanding their adaptations,” says Strait. “Examination of the microscopic damage on the surfaces of the teeth of A. sediba has led to the conclusion that the two individuals known from this species must have eaten hard foods shortly before they died. This gives us information about their feeding behavior. Yet, an ability to bite powerfully is needed in order to eat hard foods like nuts or seeds. This tells us that even though A. sediba may have been able to eat some hard foods, it is very unlikely to have been adapted to eat hard foods.”

The bottom line, Strait says, is that the consumption of hard foods is very unlikely to have led natural selection to favor the evolution of a feeding system that was limited in its ability to bite powerfully.

This means that the foods that were important to the survival of A. sediba probably could have been eaten relatively easily without high forces.

 

Nature Communications: Australopithecus sediba was limited in its ability to eat hard foods

  • Other co-authors on the study include Amanda Smith, PhD, from Washington University in St. Louis and formerly from the University at Albany; Stefano Benazzi, PhD, from the University of Bologna and the Max Planck Institute for Evolutionary Anthropology; Gerhard W. Weber, PhD, from the University of Vienna; Mark A. Spencer, PhD, from South Mountain Community College; Keely B. Carlson, PhD, from Texas A&M University; Kieran P. McNulty, PhD, from the University of Minnesota; Paul C. Dechow, PhD, Qian Wang, PhD, and Leslie C. Pryor, PhD, from the Baylor College of Dentistry at Texas A&M University; Ian R. Grosse, PhD, from the University of Massachusetts, Amherst; Callum F. Ross, PhD, from the University of Chicago; Brian G. Richmond, PhD, from the American Museum of Natural History; Barth W. Wright, PhD, from the Kansas City University of Medicine and Biosciences; Craig Byron, PhD, from Mercer University; Kelli Tamvada, PhD, from The Sage Colleges and formerly from the University at Albany; and Michael A. Berthaume, PhD, from the Max Planck Institute for Evolutionary Anthropology.

 

 

A cure in the making

- Wits University

An estimated 350 million people worldwide are infected with chronic Hepatitis B Virus (HBV) with the majority living in sub-Saharan Africa.

In South Africa, HBV infections are prevalent among Africans but it is rare in other racial groups.

While in many adults acute HBV infection does not require treatment as the infection is cleared spontaneously, PhD researcher Musa Donald Marimani is working on a possible cure for chronic HBV infections.

“Although an effective HBV vaccine has been used in South Africa since 1995, it is not beneficial to people that are chronically infected before being vaccinated. As such, development of effective HBV therapy remains a priority,” explains Marimani.

Currently, licensed HBV therapies act by inhibiting the formation of HBV DNA in hepatocytes (the cells that make up the majority of the cells in the liver) during viral replication or by activating the host’s immune system to combat the infection.

While these drugs suppress viral replication to reduce liver damage, they rarely clear the infection.

Marimani’s research involves introducing small interfering ribonucleic acid (siRNAs) as therapeutic agents into cultured mammalian cells and in HBV transgenic mice to prevent the replication of HBV.

The double stranded siRNA molecules containing single 2`-O-guanidinopropyl (GP)-modification were synthesised by Professor Joachim Engels from the Goethe University in Germany and tested for efficacy in human liver tumour cells. Similarly, siRNAs were mixed with liposomes synthesised by Professor Daniel Scherman at the Université Paris Descartes in France and tested in HBV transgenic mice.

Marimani’s research resulted in two key findings. The first is that the siRNAs were able to significantly reduce HBV replication in cultured cells without inducing toxicity or innate immune stimulation, thus prompting further efficacy studies in HBV transgenic mice.

Secondly, in these mice, GP-modified siRNAs significantly suppressed HBV replication for up to 14 days after single administration, without evidence of toxicity or innate immune stimulation, thus indicating the utility of GP-modified siRNAs in countering viral replication. These findings are useful for therapeutic application against chronic HBV infection.

How curved shock waves behave

- Wits University

Brendan Gray’s construction of a versatile and novel experimental rig contributes to the understanding of how curved shock waves behave.

Understanding curved shock wave behaviour could lead to better designs to mitigate the effects of blasting in mines or aid in modelling the impact of volcanic eruptions.

“Curved shock waves are also present in the engine intakes on supersonic aircraft and understanding the flow in these engines could lead to more efficient engine designs,” explains Gray.

Converging shock waves are also used in the formation of artificial diamonds and the production of several rare chemicals and are already used in shock wave lithotripsy – a common medical procedure used to treat severe kidney stones.

Gray’s research is supplemented by detailed experiments and simulations showing for the first time how a curved shock wave segment will reflect off a plain surface.

“Most of the previous literature has focused on straight shock waves but shock waves in the real world are rarely straight. I focus on converging shock waves, which have applications in a wide range of fields, including blast mechanics, aeronautics, manufacturing, chemistry, medicine and astrophysics,” he adds.

The problem with curved shock waves is that they are difficult to produce under experimental conditions.

Gray designed and built a facility which may be used with a conventional shock tube to produce shock waves with arbitrary two-dimensional profiles in a controlled and repeatable manner.

Together with computer simulations, he used the facility to study the propagation of complex shock waves with both concave and convex segments, some with sharp corners and some with rounded corners. This served to demonstrate the capabilities and limits of the facility.

Gray then generated imploding cylindrical shock waves and studied the interaction between these and straight wedges inclined at various angles. The primary point of interest was the geometric configuration of reflected shock waves behind the incident shock wave.

He also developed a simple numerical method for predicting the shape of the reflection and the point at which the reflection transitions from one configuration to another.

Cracking the code of the Universe

- Wits Univeristy

A hundred years ago, Albert Einstein published his theory of general relativity.

A hundred years from now, the world might be looking back to today, celebrating the cracking of String Theory.

String Theory is a highly complex theory in physics that attempts to find a solution to the question of why quantum mechanics and Einstein’s theory of general relativity are not compatible.

Where Einstein’s theory of general relativity provides a unified description of gravity as a geometric property of space and time (or spacetime), quantum mechanics provides a description of how fundamental particles build up and create the substances with which we are familiar.

While both these theories are some of the best-tested theories in science, they seem to be fundamentally irreconcilable where they both matter. String Theory establishes a link between particle physics and Einstein’s general relativity.

“This correspondence, which is unexpected and one of the most exciting areas of current research in Theoretical High Energy Physics is the subject of active research by members of the Mandelstam Institute for Theoretical Physics, based at Wits University,” says Professor João Rodrigues, Director of the Institute.

The Mandelstam Institute was established in January 2015 out of what was previously known as the Centre for Theoretical Physics at Wits.

The Institute conducts research in Theoretical High Energy Physics, Cosmology and Quantum Matter and is widely regarded as the leading university-based theoretical physics research group on the African continent.

It consists of 11 academics, eight of whom are rated by the NRF and two of whom hold DST/NRF Chairs. They are Professor Robert de Mello-Koch (Fundamental Physics and String Theory) and Professor Vishnu Jejjala (Theoretical Particle Cosmology).

“We are certainly leaders in the area of Theoretical High Energy Physics/String Theory,” adds Rodrigues.

Named after the eminent South African-born American theoretical physicist and Wits graduate, Stanley Mandelstam, who is currently Professor Emeritus at the University of California, Berkeley, the Institute has eight postdoctoral fellows and close to 30 postgraduate students. It also hosts the Gauteng node of the National Institute for Theoretical Physics.

“General relativity deals with the physics of large scales, and quantum mechanics deals with the physics of small scales, so you don’t need to worry about their incompatibility because one theory is (usually) good enough for your calculation,” says Jejjala.

However, to explain the start of the universe, or the functioning of black holes in space, you need both these theories. “Einstein’s theory tells us everything about how the Universe expands but it doesn’t explain what happened at the instant that the Universe started,” he adds. In this instance, both theories matter, but they don’t speak to each other.

Researchers in the Institute and their peers in the field believe that they are now closer to solving this riddle.

“What has happened is one of the most exciting developments in this field, and that is that there may be a link between general relativity theory and particle physics, which may allow us to understand or figure out a long-standing problem in particle physics, which is the problem of confinement,” says Jejjala.

“In certain settings, gravitational physics and non-gravitational quantum field theories are the same thing.”

While work on String Theory is still work in progress, they are closer to being able to describe the Universe in detail.

“We are certainly not done with quantum gravity or String Theory but it is a very exciting time, in that we are able to begin to address the kind of questions of how the Universe works at a very fundamental level,” concludes Jejjala.

Wits physicists involved in search for new bosons at CERN

- Wits University

Southern Africa’s talent in high energy particle physics displayed at annual workshop.

Where does Dark Matter in the Universe come from? Is the Large Hadron Collider seeing new bosons and can these bosons give mass to particles in the Universe?

In 2012, the world stood in awe as the Higgs Boson – the particle that gives known matter mass – was found at the Large Hadron Collider at CERN in Geneva, Switzerland. In 2016, the world may be astonished again, as physicists are preparing to describe a range of new phenomena, which they were previously unable to explain.

Wits physicists are at the leading edge of experiments at the Large Hadron Collider, which has been restarted in 2015 after a two-year shut-down. These experiments have reported a number of tantalising peculiarities in the data. Together with collaborators from the Harish Chandra Institute, Wits researchers have postulated in June 2015 the existence of a new boson, which is able to explain a number of these peculiarities.

In December 2015 the ATLAS and CMS experiments reported an excess of events consistent with an even heavier boson. These two bosons could explain the suite of peculiarities in the data, and predict the existence of yet two more bosons, this time with electrical charge, and a family of new particles. These particles, if confirmed with new data, would signify a revolution in Physics.

 “With the discovery of the Higgs boson a new window of opportunity has opened to discover new particles and interactions in nature. These may help us understand many unresolved mysteries, such as where most of the matter in the Universe comes from, among others,” says Professor Bruce Mellado from the Wits School of Physics. “Experiments in the LHC also provide an insight of what happened right after the Big Bang via the study of collisions of heavy ions at high energies.”

In June 2015 the LHC has resumed in providing proton-proton collisions for physics data at a record energy of 13 TeV (1012 eV). The Higgs boson was discovered with data collected at 7 TeV and 8 TeV.

Then on 25 November 2015, the first heavy ion collisions at a record energy of more than 1 PeV (1015 eV) were provided.

The results following the data analysis by the ATLAS and CMS experiments bears witness of the excellent readiness of the experiments to collect, distribute and analyze vast amounts of data in a short period of time.

“Getting these exciting results from LHC Run two depended on understanding the early measurements at this new center-of-mass energy, where the Wits group played a significant role,” says Dr Deepak Kar of the Wits School of Physics.

“The amount of data delivered in 2015 is a glimpse of what will be delivered this year. New data is expected to be delivered starting at the end of April 2016, leading to a data sample significantly bigger than obtained in 2015. This data set will give an invaluable insight on whether we will have new discoveries or not,” says Mellado.

Workshop

The High Energy Particle Physics Group at the University of the Witwatersrand hosted the second High Energy Particle Physics (HEPP) Workshop from Monday, 8 February to Wednesday 10 February. The second edition of the HEPP Workshop was aimed at training students in presenting research on High Energy Particle Physics. Lectures were given by leading researchers, including Prof. Eilam Gross, convenor of the Higgs Boson working group at the ATLAS experiment when the Higgs Boson was discovered.

“This workshop is an opportunity for over 30 Masters and PhD students from various South African institutions to give presentations on their work, on topics that include theory, phenomenology, data analysis, synergy with nuclear physics, Big Data and electronics,” says Mellado. 

“The work of these students, together with the research that we are doing at CERN is evidence of the contribution that South Africa as a whole, and Wits in particular, make to the knowledge and understanding that we have of how our world is working,” says Mellado.

The workshop was opened by Wits Deputy Vice-Chancellor Research, Prof. Zeblon Vilakazi, the Head of the Wits School of Physics, Prof. Joao Rodrigues, Dr Daniel Adams from the Department of Science and Technology, Prof. Azwinndini Muronga, President of the SA Institute of Physics, Prof. Jean Cleymans, Chair of the SA-CERN consortium.

Sterkfontein Caves produce two new hominin fossils

- Wits University

Specimens from the Homo genus and can be associated with early stone tools dated to 2.18 million years ago.

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Two new hominin fossils have been found in a previously uninvestigated chamber in the Sterkfontein Caves, just North West of Johannesburg in South Africa.

The two new specimens, a finger bone and a molar, are part of a set of four specimens, which seem to be from early hominins that can be associated with early stone tool-bearing sediments that entered the cave more than two million years ago.

“The specimens are exciting not only because they are associated with early stone tools, but also because they possess a mixture of intriguing features that raise many more questions than they give answers,” says lead researcher Dr Dominic Stratford, a lecturer at the Wits School of Geography, Archaeology and Environmental studies, and research coordinator at the Sterkfontein Caves.

The first fossil specimen, which is a very large proximal finger bone, is significantly larger and more robust than any other hand bone of any hominin yet found in South African plio-pleistocene sites.

“It is almost complete and shows a really interesting mix of modern and archaic features. For example, the specimen is markedly curved – more curved than Homo naledi and is similarly curved to the much older species Australopithecus afarensis,” says Stratford.  

The level of curvature is often linked to arborealism, but it lacks the strong muscle attachments that are expected to be present.

“The finger is similar in shape to the partial specimen from Olduvai Gorge that has been called Homo habilis, but is much larger. Overall, this specimen is unique in the South African plio-pleistocene fossil hominin record and deserves more studies,” says Stratford.

The other fossil is a relatively small, nearly complete adult 1st molar tooth that also has striking similarities to species Homo habilis.

“In size and shape it also bears a resemblance to two of the 10 1st molars of the H.naledi specimens, although further and more detailed comparisons are needed to verify this.”

The shape of the tooth and particularly the shape and relative sizes of the cones on the surface of the tooth suggest this specimen belonged to an early member of the Homo genus and can be associated with early stone tools dated recently to 2.18 million years ago.

“The two other hominin fossils found are still being studied and further excavations are planned to hopefully find more pieces and expand our understanding of who these intriguing bones belonged to and how they lived and died on the Sterkfontein hill more than two million years ago,” says Stratford.

The Sterkfontein Caves have been one of the most prolific palaeoanthropological sites in the world, since the discovery of the first ever adult Australopithecus by Robert Broom, 80 years ago this year. Since this incredible discovery, some of palaeoanthropology’s most famous finds have come from the Sterkfontein Caves, including Ms. Ples and Little Foot.

Sterkfontein remains the richest Australopithecus-bearing locality in the world and continues to yield remarkable specimens. The underground network of caves at the site extends over 5kms and the caves are filled with fossiliferous sediments that have been deposited underground over a period of more than 3.67 million years.

However, very few of these deep deposits have been systematically excavated and so remain largely unknown. The Milner Hall, where the four new hominin fossils were found, is one such chamber where several large deposits have been identified but never excavated.

The excavations that yielded these new hominin fossils were being conducted as part of a new phase of exploratory excavations away from the known hominin-bearing areas. Excavations in the Jacovec Cavern, Name Chamber and Milner Hall have been started under Dr Stratford’s direction. Each has yielded exciting new fossils that shed further light on the story of our evolution and life on the Sterkfontein hill more than two million years ago.

During the second phase of excavation in the Milner Hall, which were started early in 2015 with student Kelita Shadrach, four hominin fossils were excavated from the upper layers of a long sequence of deposits that document the long history of fossil deposition in the cave, starting over 3.67 million years ago.

Most powerful source of cosmic radiation

- Wits University

Super-massive black hole at center of Galaxy is likely to accelerate cosmic ray particles to energies 100 times larger than the Large Hadron Collider at CERN.

In yet another discovery emanating from detailed analysis of the latest data from the High Energy Stereoscopic System (H.E.S.S.) observatory in Namibia, an international team of scientists, including astrophysicists from the University of the Witwatersrand in Johannesburg, announced they have found the most powerful source of cosmic radiation at the center of our Galaxy.

The findings, published Wednesday evening (16 March 2016) in the scientific journal, Nature, reveal for the first time a source of cosmic radiation at energies never observed before in the Milky Way:

The supermassive black hole at the center of our Galaxy is likely to accelerate cosmic ray particles to energies 100 times larger than those achieved at the largest terrestrial particle accelerator, the Large Hadron Collider at European Organization for Nuclear Research (CERN) in Switzerland.

According to Professor Sergio Colafrancesco, DST/NRF SKA Research Chair in the School of Physics at Wits University, the discovery sheds light simultaneously on two fundamental aspects of nature: the understanding of the origin of cosmic rays, since the discovery of their extraterrestrial nature in 1912, and the ability of the super-massive black hole at the center of our Galaxy (as in almost every other galaxy in the universe) to accelerate the most energetic particles produced in the universe.

Says Colafrancesco: “We are therefore able to use the center of our Galaxy as a laboratory for testing the nature and the interaction properties of the most extreme particles in the universe, beyond the capability of any viable terrestrial accelerator.”

“In future our understanding of how cosmic rays travel in the Galaxy on their path to the Earth and how they interact with the material of which our Galaxy is made of, will also be further boosted by combining the H.E.S.S. gamma-ray measurements in the inner 30 light years of our Galaxy with the radio measurements of the magnetic field in the same region that will be produced by the Square Kilometre Array (SKA) and its precursor MeerKAT radio telescope.”

An enduring mystery

The Earth is constantly bombarded by high energy particles (protons, electrons and atomic nuclei) of cosmic origin, particles that comprise the so-called “cosmic radiation”. These “cosmic rays” are electrically charged, and are hence strongly deflected by the interstellar magnetic fields that pervade our galaxy. Their path through the cosmos is randomized by these deflections, making it impossible to directly identify the astrophysical sources responsible for their production. Thus, since more than a century, the origin of the cosmic rays remains one of the most enduring mysteries of science.

Fortunately, cosmic rays interact with light and gas in the neighbourhood of their sources and thus produce gamma-rays. These gamma-rays travel in straight lines, undeflected by magnetic fields, and can therefore be traced back to their origin. When a very-high-energy gamma-ray reaches the Earth, it interacts with a molecule in the upper atmosphere, producing a shower of secondary particles that emit a short pulse of “Cherenkov light”.

E.S.S. observations

By detecting these flashes of light using telescopes equipped with large mirrors, sensitive photo-detectors, and fast electronics, more than 100 sources of very-high-energy gamma-rays have been identified over the past three decades. The H.E.S.S. observatory represents the latest generation of such telescope arrays. It is operated by scientists from 42 institutions in 12 countries, including astrophysicists from the Wits School of Physics, with major contributions by MPIK Heidelberg, Germany, and CEA, CNRS, France.

Today we know that cosmic rays with energies up to approximately 100 tera-electronvolts (TeV) are produced in our Galaxy, by objects such as supernova remnants and pulsar wind nebulae.

A powerful cosmic Pevatron in the centre of the Milky Way: Artistic view of the gamma-ray emission coming from the interaction of relativistic protons, injected by the central super-massive black hole Sgr A*, with the giant clouds of the Central Molecular Zone.

About the latest discovery

Theoretical arguments and direct measurement of cosmic rays reaching the Earth however indicate that the cosmic ray factories in our Galaxy should be able to provide particles to at least one peta-electronvolt (PeV).

While many multi-TeV accelerators where discovered during the last 10 years, so far the search for the sources of the highest energy Galactic cosmic rays remained unsuccessful.

Now this latest analysis by the H.E.S.S. Collaboration as described in their research letter, titled: Acceleration of Petaelectronvolt protons in the Galactic Centre, finally provide strong indications.

During the first three years of observations, the H.E.S.S. uncovered a very powerful point source of gamma-rays in the galactic center region, as well as diffuse gamma-ray emission from the giant molecular clouds that surround it in a region approximately 500 light years across.

These molecular clouds are bombarded by cosmic rays moving at close to the speed of light, which produce gamma-rays through their interactions with the clouds’ material. A remarkably good spatial coincidence between the observed gamma-rays and the density of material in the clouds indicated the presence of one or more accelerators of cosmic rays in that region. However, the nature of the source remained a mystery.

Observing 1PeV

Deeper observations obtained by H.E.S.S. between 2004 and 2013 shed new light on the processes powering the cosmic rays in this region.

Says Aion Viana (MPIK, Heidelberg): “The unprecedented amount of data and progress made in analysis methodologies enables them to measure simultaneously the spatial distribution and the energy of the cosmic rays.”

With these unique measurements, the H.E.S.S. scientists are for the first time able to pinpoint the source of these particles. “Somewhere within the central 33 light years of the Milky Way there is an astrophysical source capable of accelerating protons to energies of about one peta-electronvolt, continuously for at least 1,000 years,” says Emmanuel Moulin (CEA, Saclay).

In analogy to the “Tevatron”, the first human-built accelerator that reached energies of 1 tera-electronvolt (TeV), this new class of cosmic accelerator has been dubbed a “Pevatron”.

“With H.E.S.S. we are now able to trace the propagation of PeV protons in the central region of the galaxy,” adds Stefano Gabici (CNRS, Paris).

Supermassive black hole at the center of our Galaxy

The center of our Galaxy is home to many objects capable of producing cosmic rays of high-energy, including, in particular, a supernova remnant, a pulsar wind nebula, and a compact cluster of massive stars.

However, the supermassive black hole located at the center of the Galaxy, called Sgr A*, is the most plausible source of the PeV protons. The scientists say several possible acceleration regions can be considered, either in the immediate vicinity of the black hole, or further away, where a fraction of the material falling into the black hole is ejected back into the environment and there initiates acceleration of particles.

Measurement of the energy spectrum of the gamma-ray emission by H.E.S.S. allows the spectrum of the protons that have been accelerated by the central black hole to be inferred. It turns out that Sgr A* is very likely accelerating protons to PeV energies.

However, it cannot account for the total flux of cosmic rays detected at the Earth. The scientists argue that if it were more active in the past then it could indeed be responsible for the entire flux of today’s cosmic rays. And if true, this would put an end to the century-old debate about the origin of the Galactic cosmic rays.

Publication: Acceleration of Petaelectronvolt protons in the Galactic Centre; H.E.S.S. collaboration; corresponding authors: F. Aharonian, S. Gabici, E. Moulin et A. Viana; Nature (16 March 2016).

South African involvement: The H.E.S.S. telescope is operated by an international collaboration of scientists with a strong involvement by South African universities, in particular Wits University, North West University, and the Universities of the Free State and Johannesburg. Wits physicists are particularly involved in data analysis techniques, the development of theoretical interpretation tools of both extragalactic and galactic sources, and in the operational shifts at the telescope location in Namibia.

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