783 research outputs found
Evaluation of a Number of Grass Species for Restoring Degraded Semi-Arid Rangelands in Southern Africa
The biophysical environment is an important determinant of land degradation in both commercial and communal land tenure systems in South Africa. According to a recent study on the status of land degradation, approximately 25% of the total land cover in South Africa is degraded. Several technologies exist to restore the soil and vegetation degraded areas in natural pastures. To improve the production and biodiversity potential for agricultural and conservation uses in these rangelands, a common restoration technology includes the cultivation the eroded and compacted soil surfaces by rip- ploughing and the re-vegetation with high productive, palatable and perennial species. Five grasses, Chloris gayana, Digitaria eriantha, Anthephora pubescens, Cenchrus ciliaris and Panicum maximum, were used in over-sowing trials in an semi-arid region with two types of soils, to evaluate their effectiveness to restore the degraded natural pasture. Results show that D. eriantha, C. gayana and P. maximum should be used in an over-sowing treatment to restore high clay or silt soil types, whereas A. pubescens and C. ciliaris are more suitable for sandy soils. The diversity in areas which were only rip-ploughed also increased considerably with palatable, perennial species such as Themeda triandra, Setaria sphacelata and Eragrostis curvula
‘We are left in the cold’: Nurses’ perceptions and responses to antiretroviral treatment roll-out in the Free State, South Africa
The unprecedented roll-out of antiretroviral therapy (ART) in South Africa is a complex process where no previous endeavour exists that can measure, predict, or direct an intervention of this scale. In the Free State province, unique characteristics and problems distinguish its ART programme, although countrywide problems also occur within the province. The Free State province faces high vacancy rates among its health-care workers, the programme has lower patient enrolment rates because of an obsessionwith quality to the detriment of quantity, and various incidents of ART shortages have also shook the province. The ART rollout intervention thus far has been largely nurse-driven (however not nurse initiated), and they form what many refer to as the ‘backbone’ of the programme. In order to respond to the challenges faced by these front-line ART providers, continuous transformations inevitably take place to respond to new needs associated with the roll-out programme, but also to strengthen the primary health-care system in general. The objective of this article is to present a typology of contradictory contextual factors in the antiretroviral programme as identified through group interviews that were conducted with PNs at public healthcare clinics in the five districts of the Free State province during 2005 and 2006. We intend to show that transformations oftenhave contradictory and problematic outcomes as expressed and perceived by the nurses themselves. This unprecedented endeavour of ART roll-out inevitably has to treasure and support its most valued implementers, i.e. the front-line providers who are not only professionals in the health-care setting, but also social agents in a wider contextual framework
The influence of school culture and school climate on violence in schools of the Eastern Cape Province
This article reports on research undertaken about the influence of school culture and school climate on violence at schools in the Eastern Cape. An adapted California School Climate and Survey – Short Form (CSCSS-SF), which was used as the data-collection instrument, was completed by 900 Grade 10 to 12 learners. With the assistance of Pearson’s product moment correlation coefficient, it was found that the better the school culture and school climate are at a school, the lower the levels of school violence. On the other hand, a lack of school safety contributed to learners experiencing higher levels of violence at schools. The results of hierarchy regression analyses indicated that school culture and school climate can be used to explain a significant percentage of variance in school violence. The f 2 values indicate that, with the exception of two aspects of the variance physical and verbal harassment,the results did not have any practical value. The article concludes with a few suggestions on how the results can be used to address school violence.Keywords: CSCSS-SF; school climate; school culture; school violenc
Helioseismic Ring Analysis of CME Source Regions
We apply the ring diagram technique to source regions of halo coronal mass
ejections (CMEs) to study changes in acoustic mode parameters before, during,
and after the onset of CMEs. We find that CME regions associated with a low
value of magnetic flux have line widths smaller than the quiet regions implying
a longer life-time for the oscillation modes. We suggest that this criterion
may be used to forecast the active regions which may trigger CMEs.Comment: Accepted for publication in J. Astrophys. Astr. Also available at
http://www2.nso.edu/staff/sushant/paper.htm
Primary keratinocyte cell culture on EpiGen membranes for autologous skin grafts in paediatric burn patients
Cultured epithelial autografts have been shown to be an effective permanent skin replacement for major burn injuries and have proved life-saving when insufficient donor skin has been available. Several membrane systems have been developed that facilitate the transfer of cultured cells on to the recipient. The aim of the study reported here was to test the effectiveness of EpiGen, a synthetic polymer membrane, as a cell culture support matrix for the transplantation of cultured autografts. Skin biopsies were obtained from 22 paediatric burn patients with an affected total body surface area of between 7% and 80%. Basal keratinocytes were harvested from the dermal/epidermal junction and cultured in a collagen 1-coated flask in modified Green’s medium. After two passages, isolated keratinocytes were grown on EpiGen membranes until semiconfluent. Wound beds were excised and covered with widely (1:3) meshed split skin grafts. Membranes were grafted with the basal cell layer directed against the wound bed. Unseeded membranes were applied and served as controls. Wounds were dressed and closed appropriately. Grafts were regularly inspected for ‘take’ and the membranes were removed 10 days after application. Seven patients had to be excluded from the study. Cell culture results of the remaining 15 patients showed excellent cell growth and expansion on EpiGen membranes within a mean culture time of 2.6 days post membrane seeding. The membranes facilitated easy transfer of cultures onto the recipient. A mean keratinocyte graft ‘take’ of 95% and a mean control graft ‘take’ of 90% were recorded at the time of membrane removal. The mean level of clinically evident re-epithelialization on keratinocyte grafted areas in recipients was 87% as opposed to 60% in the unseeded control areas
Academic Specialties in U.S. Are Shifting; Hiring of Women Geoscientists Is Stagnating
Women have been receiving a greater proportion of the bachelor’s and master’s degrees in the geosciences over the last 10 years, reaching near 40% in 2000 (latest data available), while receiving only 28% of the Ph.D.s that year. Women are now only 20% of assistant professors at Ph.D.-granting institutions, a proportion that has not changed in the last four years. As part of a larger study to find what key barriers continue to prevent larger numbers of women geoscientists from becoming academics, data have been compiled from the National Science Board [NSB, 2002], and the American Geological Instititute\u27s (AGI) Directory of Geoscience Departments [Claudy, 2001] on geoscience specialty by gender
Multisite Phosphorylation Modulates the T Cell Receptor ζ-Chain Potency but not the Switchlike Response
AbstractMultisite phosphorylation is ubiquitous in cellular signaling and is thought to provide signaling proteins with additional regulatory mechanisms. Indeed, mathematical models have revealed a large number of mechanisms by which multisite phosphorylation can produce switchlike responses. The T cell antigen receptor (TCR) is a multisubunit receptor on the surface of T cells that is a prototypical multisite substrate as it contains 20 sites that are distributed on 10 conserved immunoreceptor tyrosine-based activation motifs (ITAMs). The TCR ζ-chain is a homodimer subunit that contains six ITAMs (12 sites) and exhibits a number of properties that are predicted to be sufficient for a switchlike response. We have used cellular reconstitution to systematically study multisite phosphorylation of the TCR ζ-chain. We find that multisite phosphorylation proceeds by a nonsequential random mechanism, and find no evidence that multiple ITAMs modulate a switchlike response but do find that they alter receptor potency and maximum phosphorylation. Modulation of receptor potency can be explained by a reduction in molecular entropy of the disordered ζ-chain upon phosphorylation. We further find that the tyrosine kinase ZAP-70 increases receptor potency but does not modulate the switchlike response. In contrast to other multisite proteins, where phosphorylations act in strong concert to modulate protein function, we suggest that the multiple ITAMs on the TCR function mainly to amplify subsequent signaling
Identification of depression in a rural general practice
Major depression is underdiagnosed by general practitioners, but the reasons for this are not clear. This study aimed to establish the prevalence of major depression and coexisting generalised anxiety disorder in a rural general practice in the Orange Free State. It also assessed the predictive value of a screening questionnaire for use by general practitioners. The two practitioners evaluated 858 patients over a 4-week period. Those who met the screening criteria, together with a random sample of 60 patients who did not, were re-evaluated by a registrar in psychiatry who was unaware of the findings of his colleagues. Of the patients studied, 134 (15,6%) had major depression; 59 of these (44,0%) also had coexisting generalised anxiety disorder. The general practitioners had . correctly diagnosed major depression in 32 patients (3,7%) before the study started. The screening questionnaire had a 42% chance of correctly identifying a patient with depression and a 97% chance of correctly identifying a patient who did not have major depression. Both practitioners were equally capable at identifying major depression. The study confirmed both the high prevalence of depression in a rural general practice and its low identification rate. It also showed the advantage of using a screening questionnaire to alert practitioners to the possibility of depression in their patients
Training South African clinician-scientists: Lessons from the University of Cape Town’s intercalated programme
In 2011, the Faculty of Health Sciences at the University of Cape Town, South Africa (SA), established the Clinician-Scientist Training Programme (UCTCSTP), consisting of intercalated BMedSci Hons/MB ChB and integrated MB ChB/MSc/PhD tracks. We report and reflect on the programme’s performance and challenges. The UCTCSTP has so far enrolled 71 students: 51 have received BMedSci Hons degrees and 4 have received Master’s degrees, while there are 14 BMedSci Hons, 4 MSc and 4 PhD candidates. Graduates have produced significant research outputs, and many remain actively engaged in research. The UCTCSTP has been successful in encouraging a cohort of future clinician-scientists, but should aim to broaden and improve its appeal to address the need to transform and grow the SA clinical academic workforce. As graduates progress with their postgraduate clinical training, they require institutional support and guidance, which may necessitate policy reform
Prolonged Drying Trend Coincident with the Demise of Norse Settlement in Southern Greenland
Declining temperature has been thought to explain the abandonment of Norse settlements, southern Greenland, in the early 15th century, although limited paleoclimate evidence is available from the inner settlement region itself. Here, we reconstruct the temperature and hydroclimate history from lake sediments at a site adjacent to a former Norse farm. We find no substantial temperature changes during the settlement period but rather that the region experienced a persistent drying trend, which peaked in the 16th century. Drier climate would have notably reduced grass production, which was essential for livestock overwintering, and this drying trend is concurrent with a Norse diet shift. We conclude that increasingly dry conditions played a more important role in undermining the viability of the Eastern Settlement than minor temperature changes
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