Optical trapping, biomolecules and cooperativity

Schmidt, C.F. [Promotor]Stienen, G.J.M. [Promotor]Wuite, G.J.L. [Copromotor

A rough estimate of the proportion of global emissions from agriculture due to smallholders

Smallholders in developing countries produce, on a very rough estimate, 5% of total global greenhouse gas emissions. This figure includes emissions due to both agriculture and land use change for agriculture. Mitigation actions in smallholder agriculture now could support farm livelihoods and more sustainable agriculture in the long run, but should only be introduced where they have the potential to advance rather than constrain rural development outcomes

Developing non-cognitive skills in part-time students at a South African university: Overcoming negativity and supporting behavioural change

This paper reports on the findings of an intervention aimed at assisting a group of thirty-one part-time students registered for a third year Management Accounting and Finance course to develop a range of non-cognitive skills that have been shown to positively impact academic behaviour. In addition to facilitating the teaching and learning of academic content, lecturers introduced students to academic mindsets, academic behaviours, learning strategies and social skills through role-plays and practical demonstrations. The intervention also strove to influence the context in which students learned in order to positively influence the attitudes of the students towards the course and to motivate them to acquire and practice behaviours that would support their learning. The intervention involved two action research cycles in which the researchers were able to reflect on the effectiveness of the various approaches used to encourage behaviour change and the acquisition of new skills. The findings of the study indicate that the intervention was successful in developing a range of non-cognitive attitudes, strategies and behaviours in students, with most of the cohort reporting positive changes in attitude towards their studies and the belief that academic success was indeed possible

Molecular footprint of drug-selective pressure in a human immunodeficiency virus transmission chain

Known human immunodeficiency virus (HIV) transmission histories are invaluable models for investigating the evolutionary and transmission dynamics of the virus and to assess the accuracy of phylogenetic reconstructions. Here we have characterized an HIV-1 transmission chain consisting of nine infected patients, almost all of whom were treated with antiviral drugs at later stages of infection. Partial pol and env gp41 regions of the HIV genome were directly sequenced from plasma viral RNA for at least one sample from each patient. Phylogenetic analyses in pol using likelihood methods inferred an evolutionary history not fully compatible with the known transmission history. This could be attributed to parallel evolution of drug resistance mutations resulting in the incorrect clustering of multidrug-resistant virus. On the other hand, a fully compatible phylogenetic tree was reconstructed from the env sequences. We were able to identify and quantify the molecular footprint of drug-selective pressure in pol using maximum likelihood inference under different codon substitution models. An increased fixation rate of mutations in the HIV population of the multidrug-resistant patient was demonstrated using molecular clock modeling. We show that molecular evolutionary analyses, guided by a known transmission history, can reveal the presence of confounding factors like natural selection and caution should be taken when accurate descriptions of HIV evolution are required.status: publishe