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05 June 2018 Photo Supplied
Digging up truth South Africa was way different to what you thought
Archaeological excavations in the Wonderwerk Cave, north of Kuruman in the Northern Cape.

Research fellow Dr Lloyd Rossouw from the Department of Plant Sciences at the University of the Free State (UFS) recently published an article in the Nature Ecology and Evolution journal with Dr Michaela Ecker from the University of Toronto as lead author, and Dr James Brink, research fellow at the UFS Centre for Environmental Management. The findings described in “The palaeoecological context of the Oldowan-Acheulean in southern Africa” provides the first extensive paleoenvironmental sequence for the interior of southern Africa by applying a combination of methods for environmental reconstruction at Wonderwerk Cave, which have yielded multiple evidence of early human occupation dating back almost two million years ago.

Where water once was
The Wonderwerk Cave is found north of the Kuruman hills (situated in Northern Cape) a 140m long tube with a low ceiling. The surroundings are harsh. Semi-arid conditions allow for the survival of only hardy bushes, trees, and grasses. But during the Early Pleistocene, stepping out of the Wonderwerk Cave you would have been greeted by a completely different site, the researchers found. Using carbon and oxygen stable isotope analysis on the teeth of herbivores (Dr Ecker), fossil faunal abundance (Dr Brink), as well as the analysis of microscopic plant silica remains (phytoliths) excavated from fossil soils inside the cave (Dr Rossouw), the results show that ancient environments in the central interior of southern Africa were significantly wetter and housed a plant community unlike any other in the modern African savanna. 

What difference does it make?
While East African research shows increasing aridity and the spread of summer-rainfall grasslands more than a million years ago, the results from this study indicate an interesting twist. During the same period, shifts in rainfall seasonality allowed for alternating summer and winter-rainfall grass occurrences coupled with prolonged wetlands, that remained major components of Early Pleistocene (more or less the period between one and two million years ago) environments in the central interior of southern Africa. That means our human ancestors were also living and evolving in environments other than the generally accepted open, arid grassland model.

News Archive

Harvard couple to present lectures on Biostatistics and Mathematics at the UFS
2015-12-07


Professor Donald Rubin

Prof Donald Rubin (John L. Loeb Professor of Statistics at Harvard University) and Elizabeth Zell (MStat - mathematical statistician in the Division of Bacterial Diseases) will visit the University of the Free State (UFS) where they will present lectures on their respective work.

Over his prestigious academic career, Prof Don Rubin’s 400 publications and 13 books have earned him around 180 000 citations at an h-index of 113. He is one of the most cited statisticians/mathematicians/economists/psychologists in the world over the last 10 -15 years. He has supervised 35 PhD candidates as sole-supervisor, 17 more as co-supervisor, with a further eight in the pipeline.

Prof Rubin who will meet with UFS academics in the Department of Mathematics and Actuarial Sciences will also deliver a lecture: Rerandomisation to improve covariate balance in experiments.

Randomised experiments are the “gold standard” for estimating causal effects, yet in practice, chance imbalances often exist in covariate distributions between treatment groups. If covariate data are available before units are exposed to treatments, these chance imbalances can be mitigated by first checking covariate balance before the physical experiment takes place. Provided a precise definition of imbalance has been specified in advance, unbalanced randomisations can be discarded, followed by a rerandomisation. This process can continue until a randomisation yielding balance according to the definition is achieved. By improving covariate balance, rerandomisation provides more precise and trustworthy estimates of treatment effects.

Prof Rubin received an honorary professorship from the Faculty of Natural and Agricultural Sciences at the UFS.


Elizabeth Zell

The lecture will take place on:
Date: Tuesday 8 December 2015
Time: 16:00
Venue: Albert Wessels Auditorium, Bloemfontein Campus

Zell earned her Master’s degree in Statistics at North Carolina State University, and for more than two decades, was an active bio-statistical researcher in various offices of the Centers for Disease Control (CDC). Since 2013, she has been the Principal Statistician and President of Stat-Epi Associates, Inc. Her 150+ publications have earned her 14 500 citations at an h-index of over 50. She is a Fellow of the American Statistical Association, and, in 2010, she received the Statistics Section Government Award for outstanding contributions to statistics and public health by the American Public Health Association. During her career at the CDC, she earned more than 20 CDC research awards and honours.

She will deliver two lectures at the UFS. The first is entitled A Potential Outcomes Approach to Documenting the Public Health Impact of the Introduction of PCV13 for the Prevention of Invasive Pneumococcal Disease. The topic of her second lecture is: Assessing the Effectiveness of Intrapartum Antibiotic Prophylaxis for Prevention of Early-Onset Group B Streptococcus Disease through Propensity Score Design

Elizabeth’s lectures will take place on:
Date: Wednesday 9 December 2015
Time: 10:45 and 13:00
Venue: West Block 111, Bloemfontein Campus

For more information, please contact Dr Michael von Maltitz at VMaltitzMJ@ufs.ac.za.

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