Digit ratio as an endophenotype in a schizophrenia population

CITATION: Nieuwoudt, W. D. B. et al. 2021. Digit ratio as an endophenotype in a schizophrenia population. South African Journal of Psychiatry, 27:a1587, doi:10.4102/sajpsychiatry.v27i0.1587.The original publication is available at https://sajp.org.zaBackground: Schizophrenia is a debilitating mental health condition affecting the lives of many South Africans. The origins of the heterogeneity in the presentation of the illness remain uncertain. Aim: This cross-sectional study performed a retrospective data analysis to determine the usefulness of digit ratio as an endophenotype in a South African schizophrenia population. Setting: A large genetic study in a South African schizophrenia population recruited patients from services in the Western and Eastern Cape. Methods: Complete clinical histories were captured for participants, including sets of images of the face and extremities. Software was utilised to measure the lengths of participants’ digits from said images and digit ratios (2D:4D) were calculated. Descriptive analyses were performed on the ratios and statistical differences in digit ratio means were calculated between groups characterised by sex, age of onset and the presence vs absence of positive symptoms. Linear modelling was utilised to assess for correlates between 2D:4D and positive and negative symptom severity using scores obtained from the Positive and Negative Syndrome Scale (PANSS) and Scale for the Assessment of Negative Symptoms (SANS). Results: 2D:4D in male participants did not significantly differ from female participants as in healthy populations. 2D:4D did not significantly correlate with the severity of positive or negative symptoms and 2D:4D means between groups did not significantly relate to age of onset. Conclusion: 2D:4D appears to be a possible endophenotype in schizophrenia in this population. 2D:4D, however, may not be as readily identifiable as certain minor physical anomalies and neurological soft signs significantly associated with schizophrenia in this population.https://sajp.org.za/index.php/sajp/article/view/1587Publisher's versio

Development of an engine testing facility for spark ignition engine fuels

Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This thesis comprises of the development of a facility were spark ignition engine fuels can be tested. Development of the facility included the installation of a standard spark ignition engine, an engine dynamometer, control and monitoring equipment, control and monitoring software, and an in-cylinder pressure measurement setup. The system was tested using petrol as well as a petrol-ethanol blend. The results indicated good accuracy and repeatability of the system. Analysis of the performance and combustion of the petrol-ethanol blend showed no significant difference in comparison to the petrol fuel. The petrol-ethanol blend showed a slight increase in oxygen content and fuel consumption as well as an increase in CO2 emissions and a decrease in CO emissions. During the project, a comparison was also made between the performance of fibre optic transducers and a piezoelectric transducer. It was found that the fibre optic transducers performed similarly to the piezoelectric transducer during low engine load conditions. At high load conditions however, the fibre optic transducers were not able to produce the same accuracy as the piezoelectric transducer.AFRIKAANSE OPSOMMING: Hierdie tesis bestaan uit die ontwikkeling van 'n fasiliteit waar brandstowwe vir 'n vonkontsteking binnebrandenjin getoets kan word. Ontwikkeling van die fasiliteit sluit in die installering van 'n standaard vonkontsteking binnebrandenjin, 'n enjin rem, beheer en monitering toerusting, beheer en monitering sagteware, en 'n insilinder drukmeting opstelling. Die fasiliteit is getoets met suiwer petrol sowel as 'n petrol-etanol mengsel. Die resultate het hoë vlakke van akkuraatheid en herhaalbaarheid getoon. Ontleding van die werksverrigting en verbranding van die petrol-etanol mengsel het geen beduidende verskil getoon in vergelyking met die suiwer petrol brandstof nie. Die petrol-etanol mengsel het 'n effense toename in suurstofinhoud, brandstofverbruik, sowel as CO2 vrylating en 'n afname in CO vrylating getoon. Tydens die projek is 'n vergelyking getref tussen die akkuraatheid van optiese vesel drukmeters en 'n piësoëlektriese drukmeter. Daar is bevind dat die akkuraatheid van die optiese vesel drukmeters soortgelyk is aan die piësoëlektriese drukmeter gedurende lae enjin lastoestande. By hoë las omstandighede was die optiese vesel drukmeters egter nie in staat om dieselfde akkuraatheid as die piësoëlektriese drukmeter te handhaaf nie

Story skills and hierarchies of needs and values: a defence of the humanities

This article1 1The article was developed as a thought paper in the NRF's project Shifting Boundaries of Knowledge – The Role of Social Sciences, Law and Humanities. A first version was presented at a regional workshop of the project at Tshwane University of Technology on 28 May 2004. View all notes is a defence of the humanities that emphasises the nature and value of humanistic knowledge. I firstly outline the present negative perceptions of the humanities and the factors that constrain their development in South Africa. Chief among them is the privileging of technical rational knowledge above Bildung and self-development. Against the background of views on social dedifferentiation and the end of the book I emphasise the career value of the humanities. I try to reverse the opposition between technical rationalist knowledge and Bildung by analysing Maslow's hierarchy of needs and confronting his theory with a number of findings of our recent research into identity and literary space. Two keywords that feature strongly are centrality and narrativity. The implications of this view are explored in a brief analysis of Eben Venter's novel Foxtrot van die vleiseters (1993) [Foxtrot of the Meat-eaters].http://dx.doi.org/10.1080/0256471080202481

Bioenergy and Land Use Change-State of the Art

The dedicated production of biomass crops and the collection of residues in agriculture and forestry can lead to undesirable negative impacts and it is crucial that practices are found that ensure that these impacts are avoided or mitigated as far as possible. This chapter concerns the use of biomass for energy and the connection between increased bioenergy use and land use change (LUC). Land use and LUC associated with bioenergy can lead to a multitude of environmental and socioeconomic consequences. The chapter focuses on the question whether greenhouse gas (GHG) emissions associated with LUC could undermine the climate change mitigation benefits of bioenergy. There are, however, several options for mitigating these emissions that can be implemented: development of bioenergy feedstock production systems that integrate with existing agriculture and forestry production, enhancement of land use productivity in agriculture and forestry in general, and legal protection of natural ecosystems

Bioenergy and land use change-state of the art

Bioenergy projects can lead to direct and indirect land use change (LUC), which can substantially affect greenhouse gas balances with both beneficial and adverse outcomes for bioenergy\u27s contribution to climate change mitigation. The causes behind LUC are multiple, complex, interlinked, and change over time. This makes quantification uncertain and sensitive to many factors that can develop in different directions-including land use productivity, trade patterns, prices and elasticities, and use of by-products associated with biofuels production. Quantifications reported so far vary substantially and do not support the ranking of bioenergy options with regard to LUC and associated emissions. There are however several options for mitigating these emissions, which can be implemented despite the uncertainties. Long-rotation forest management is associated with carbon emissions and sequestration that are not in temporal balance with each other and this leads to mitigation trade-offs between biomass extraction for energy use and the alternative to leave the biomass in the forest. Bioenergy\u27s contribution to climate change mitigation needs to reflect a balance between near-term targets and the long-term objective to hold the increase in global temperature below 2 degrees C (Copenhagen Accord). Although emissions from LUC can be significant in some circumstances, the reality of such emissions is not sufficient reason to exclude bioenergy from the list of worthwhile technologies for climate changemitigation. Policy measures to minimize the negative impacts of LUC should be based on a holistic perspective recognizing the multiple drivers and effects of LUC