Through a Green Gaze: Tentative Indicators of a Green ‘Text’

This paper seeks to re-claim for the idea ‘green’, something of the depth and range of its philosophical and ideological ideas at the time of its emergence and early formation from the 1960s to the 1990s, ideas which appear today to be largely unknown, forgotten or deliberately sidelined. It also seeks to provide for political, economic and environmental opinion-makers and decision-takers, a list of indicators by which to assess the green-ness of a ‘text’. The paper is also useful for educators wishing to examine the philosophical foundations of their practice and the texts that they use in educational work

Ethical Risks of Environmental Policies: The Case of Ethanol in North America

Policy to address the environmental impacts of transportation fuel derived from conventional oil is frequently focused on the promotion of alternatives such as biofuels. While there are some biofuels that can be developed with relatively few impacts, others can result in broader, complex social concerns that should be included in the policy debate. These concerns include impacts arising from the conversion of natural landscapes and changes in food supply. To help inform policy development, this paper raises a series of questions to encourage a fuller debate and proposes a methodology to capture ethical risks related to the energy and environmental choices. This methodology should be applied to policies that encourage a transition to fuel alternatives for transportation – whether unconventional fossil fuels or corn ethanol. Energ

Genetic parameters of testicular measurements in Merino rams and the influence of scrotal circumference on total flock fertility

Genetic parameter estimates for scrotal circumference (SC), testis diameter (TD) and two-tooth liveweight (LW) were obtained for 1380 two-tooth Merino rams born from 1986 to 1998 on the Tygerhoek Experimental Farm. The effect of SC of service sires (n = 263) on ewe fertility was also investigated. Year of birth, selection group and LW were significant sources of variation for both SC and TD. SC had a significant effect on ewe fertility. Heritability estimates ranged from 0.29 to 0.40, 0.25 to 0.38 and from 0.49 to 0.52 for SC, TD and LW, respectively. Adjustment for LW decreased heritability estimates of SC and TD and the genetic correlations between the latter traits. Rams with an unadjusted SC of less than 30 cm should not be used. South African Journal of Animal Science Vol.32(2) 2002: 76-8

Variation in sex determination and the application of the YY male technology for the production of all-male populations of the tilapia Oreochromis mossambicus

Thesis (MPhil)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Tilapia is presumed to have a well-defined genetic mechanism of sex determination, but not all sex ratios are compatible with a monofactorial sex determination model. A theory of autosomal gene influence, as well as temperature sex determination (TSD) has been proposed in order to explain large variations in sex ratios. This study assessed the variation in progeny sex ratio in O. mossambicus as a basis for the application of YY male technology in the production of all-male progeny groups. Three populations of O. mossambicus were sampled that are representative of the geographical distribution of the species in Southern Africa. Progeny groups were produced from randomly selected parents and maintained at constant temperature during the labile period of sex differentiation. Variation in sex ratios between different families of the same strain as well as between different strains was calculated. No significant differences were observed in sex ratio between strains, though a significant intra-group variation was identified. This study identified both male and female-biased sex ratios. The data in general conform to a monofactorial sex determination model. Male-biased sex ratio observed in one strain can possibly be ascribed to temperature sex determination (TSD). This strain of O. mossambicus originated from an area with different annual temperature patterns and the possibility of TSD having an adaptive advantage is discussed. This thesis also presents the results of a program to produce monosex male tilapia through the application of the YY male technology in O. mossambicus. Viable XY female and YY male genotypes were produced. XY females sired progenies ranging from 68-94% male ofspring, while YY males sired a mean progeny of 94% male phenotypes. From these results it is concluded that YY male technology provide a viable method for the production of all-male progeny in O. mossambicus. Once available on a commercial scale, the technology can be made more reliable through the application of the appropriate selection methods.AFRIKAANSE OPSOMMING: Tilapia spesies is oorwegend onderworpe aan ‘n goed gedefinieerde enkelfaktor model van genetiese geslagsbepaling, hoewel afwykings van sodanige geslagsbepalingsmodel soms waargeneem word. Die invloed van outosomale gene, sowel as omgewings temperatuur word voorgehou as verklaring van die waargenome variasies in geslagsverhoudings. Hierdie studie behels die evaluasie van variasie in geslagsdifferensiasie van O. mossambicus as basis vir die implementering van die YY manlike tegnologie vir die produksie van slegs-manlike nageslag groepe. Monsters is bekom van drie populasies van O. mossambicus verteenwoordigend van die geografiese verspreiding van die spesie in Suider Afrika. Nageslag groepe is geproduseer vanaf ewekansig gekose ouerpare en by ‘n konstante temperatuur gehuisves tydens die sensitiewe tydperk van geslagsdifferentiasie. Variasie in geslagsverhouding tussen verskillende families binne dieselfde subpopulasie sowel as binne verskillende populasies is bepaal. Geen betekenisvolle verskille is waargeneem in die geslagsverhouding tussen die verskillende populasies nie terwyl betekenisvolle verskille tussen families binne ‘n populasie waargeneem is. Die data voldoen aan ‘n enkelfaktor genetiese geslagsbepalingsmodel, met die uitsondering van een populasies waar ‘n moontlike omgewingsverwante geslagsbepalingseffek waargeneem is. Die tesis sluit ook in die resultate in van ’n program om YY-tegnologie in O. mossambicus te vestig ten einde manlike nageslag groepe te produseer. Funksionele vroulike XY- en manlike YY genotipes is ontwikkel. Die vroulike XY-genotipes het manlike nageslag groepe opgelewer wat wissel van 68%-94% manlik, terwyl manlike YY-genotipes nageslag groepe gelewer het wat gemiddeld 94% manlik was. Die resultate bevestig die lewensvatbaarheid van YY-tegnologie vir die kommersiële produksie van manlike nageslaggroepe in O. mossambicus

Applicability and fairness of the oral examination in undergraduate psychiatry training in South Africa

Objective: There are several methods of evaluating medical students’ performance, such as written examination, oral examination and objective structured clinical examination (OSCE). Many studies have focused on the reliability and validity of these methods but few studies have explored comparison between these methods. Psychiatry is the only subject at the University of Stellenbosch where the final assessment consists of solely an oral component. The aim of the study was to compare students’ final overall and discipline specific examination marks (i.e. in the other subjects) with the examination marks in psychiatry, and to determine if content or structure (e,g. oral, written or OSCE format) of examination impacts more on the student performance in the examination. Method: 343 final year medical students were included. All undertook their psychiatry rotation at the University of Stellenbosch, South Africa during 2008 and 2009. Data of marks obtained in all the disciplines during 2008 and 2009 were collected and class marks were compared with their final examination marks across all disciplines. Bland-Altman plots were used to assess the level of agreement between the class and examination marks. Cases below the lower threshold were compared to all other cases across all disciplines. The odds ratio for group status was calculated for gender distribution of examiners. Results: The psychiatry class mark and final oral examination mark provided similar measures within a width of 31.5. Cases below the threshold had poorer performance in two other disciplines. The gender distribution of the examiners (female-female) significantly increased the odds ratio for poorer performance in the oral examination.Conclusion: The results suggest that a group of students underperform in their final examination independent of method of evaluation and that the gender of examiners impacts on examination marks. Therefore future research should focus on identifying and modifying factors (including choice of examiner combinations) that contribute to the poor performance of medical students in their final examination, in order to help students perform better. Gender distribution of examiners should also be considered when examinations are structured and designed.Keywords: Oral; Medical; Student; Gender; Examiner; Performance; OSC

Measuring monopole and dipole polarizability of acoustic meta-atoms

© 2018 Author(s). We present a method to extract monopole and dipole polarizability from experimental measurements of two-dimensional acoustic meta-atoms. In contrast to extraction from numerical results, this enables all second-order effects and uncertainties in material properties to be accounted for. We apply the technique to 3D-printed labyrinthine meta-atoms of a variety of geometries. We show that the polarizability of structures with a shorter acoustic path length agrees well with numerical results. However, those with longer path lengths suffer strong additional damping, which we attribute to the strong viscous and thermal losses in narrow channels

Spherezymes: A novel structured self-immobilisation enzyme technology

<p>Abstract</p> <p>Background</p> <p>Enzymes have found extensive and growing application in the field of chemical organic synthesis and resolution of chiral intermediates. In order to stabilise the enzymes and to facilitate their recovery and recycle, they are frequently immobilised. However, immobilisation onto solid supports greatly reduces the volumetric and specific activity of the biocatalysts. An alternative is to form self-immobilised enzyme particles.</p> <p>Results</p> <p>Through addition of protein cross-linking agents to a water-in-oil emulsion of an aqueous enzyme solution, structured self-immobilised spherical enzyme particles of <it>Pseudomonas fluorescens </it>lipase were formed. The particles could be recovered from the emulsion, and activity in aqueous and organic solvents was successfully demonstrated. Preliminary data indicates that the lipase tended to collect at the interface.</p> <p>Conclusion</p> <p>The immobilised particles provide a number of advantages. The individual spherical particles had a diameter of between 0.5–10 μm, but tended to form aggregates with an average particle volume distribution of 100 μm. The size could be controlled through addition of surfactant and variations in protein concentration. The particles were robust enough to be recovered by centrifugation and filtration, and to be recycled for further reactions. They present lipase enzymes with the active sites selectively orientated towards the exterior of the particle. Co-immobilisation with other enzymes, or other proteins such as albumin, was also demonstrated. Moreover, higher activity for small ester molecules could be achieved by the immobilised enzyme particles than for free enzyme, presumably because the lipase conformation required for catalysis had been locked in place during immobilisation. The immobilised enzymes also demonstrated superior activity in organic solvent compared to the original free enzyme. This type of self-immobilised enzyme particle has been named spherezymes.</p

The neural correlates of intimate partner violence in women

Objective: To examine hippocampal volume and white matter tracts in women with and without intimate partner violence (IPV). Method: Nineteen women with IPV exposure in the last year, and 21 women without IPV exposure in the last year underwent structural magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) sequences. Additional data on alcohol use and presence of psychiatric disorder was collected. Differences in fractional anisotropy (FA) between the two groups were examined, using a statistical model that included demographic measures, alcohol use and psychiatric disorder. Results: IPV subjects did not demonstrate significantly different hippocampal volumes compared to subjects without recent IPV. FA was, however, significantly reduced in the body of the corpus callosum of IPV subjects. Adjusting for age, alcohol use, smoking and psychiatric diagnosis did not change the significance of the result. Conclusion: Data on hippocampal volume in IPV are inconsistent, perhaps reflecting the fact that multiple factors influence this measure. Reduced FA in the body of the corpus callosum in IPV suggests altered integrity of this white matter tract; additional work is needed to address the underlying mechanisms and clinical correlates of this finding

Calcific uraemic arteriolopathy (calciphylaxis) in patients on renal replacement therapy

Background. Calcific uraemic arteriolopathy (calciphylaxis) is an unusual and potentially fatal condition characterised by small-vessel calcification and ischaemic skin necrosis. It mainly affects patients with end-stage renal disease (ESRD) on haemodialysis, but may rarely occur in the absence of ESRD in conditions such as primary hyperparathyroidism, malignancy, alcoholic liver disease and connective tissue disease.Methods. We reviewed the records of all patients diagnosed with calciphylaxis while on renal replacement therapy at Tygerberg Hospital, Cape Town, South Africa, between 1990 and 2014, to describe its presentation, course and final outcome.Results. Nineteen patients developed calciphylaxis over this period. Their median age was 34 years and 13 (68.4%) were female. Fifteen (78.9%) had received a kidney transplant. All patients had painful skin lesions that rapidly progressed to infarction. Small-vessel calcification was seen on skin biopsy in 13 patients. Twelve patients had hyperparathyroidism. Several of the transplanted patients had been treated for graft rejection in the year preceding the diagnosis. Treatment consisted of good wound care and efforts to normalise serum calcium and phosphate levels. Five patients received an urgent parathyroidectomy. The outcome was fatal in 17 patients, with sepsis being the main cause of death.Conclusions. In our patients, calciphylaxis carried a worse prognosis than previously reported internationally. It should always be considered in the differential diagnosis of painful skin lesions in the dialysis or transplant patient