180 research outputs found
ADOPTION OF VETERINARY SURGEON SERVICES BY SHEEP AND GOAT FARMERS IN QWAQWA
A number of technology transfer (diffusion) programmes involving amongst others veterinary surgeon services subsidised by the government, were launched in the former homelands of South Africa between 1980 and 1993. Many of these programmes were discontinued after the general election of 1994. In order to evaluate the adoption of technology in Qwaqwa, a former Sotho speaking homeland, two Logit models were fit using the conventional definition of an adopter and an adapted definition, which included potential adopters with the adopters. Where the conventional definition of adoption was estimated, livestock income per LSU, ram technology, roads and suppliers of livestock inputs are significant variables contributing to adoption. The results of the adapted model reveal that farming efficiency (weaning percentage), type of farmer (sheep as percentage of the total small ruminant herd) and ram technology, prove to be significant variables predicting adoption. It was also found that the characteristics of potential adopters gravitate more to adopters than to non-adopters. These results indicated that the adapted definition presented a more accurate prediction than the conventional definition. The results of this study indicate the policy necessary to further accelerate the diffusion of veterinary surgeon services by means of the development of a better infrastructure, the reintroduction of subsidised veterinary surgeon services at the sheering sheds as well as a better flow of information to farmers in Qwaqwa.Livestock Production/Industries,
The influence of stocking rate and male:female ratio on the production of breeding ostriches (Struthio camelus spp.) under commercial farming conditions
The study provides information on the reproductive performance of ostriches maintained at different stocking rates and male:female (M:F) ratios under intensive commercial conditions in the Little Karoo, South Africa. Breeding ostriches are concentrated on relatively small areas and through trampling have a most significant impact on the vegetation in the Little Karoo. Reproductive performance, as influenced by stocking rate and M:F ratio, was investigated. Stocking rates for the large flocks ranged from 114 to 210 birds/ha, and stocking rates for smaller flocks ranged between 9 to 13 birds in 0.13 ha and 0.30 ha camps, respectively. The different M:F ratios investigated, were 1M:1F (pairs), 1M:2F (trios) and 1M:3F (quads), for breeding systems maintained in 0.06 ha camps. In almost all breeding systems total and average egg production, fertility and hatchability were compromised when stocking rate was increased. High stocking rates were detrimental to the reproductive performance and reproductive behaviour of the flocks. Increasing the number of females per male had no negative influence on the reproduction traits, with a significantly higher production observed for breeding quads. Our findings indicated that ostrich breeding flocks can be maintained at stocking rates higher than those presently used on commercial ostrich farms. Breeding pairs, trios and quads can also be maintained on smaller areas, with acceptable production levels. Increasing stocking densities will have a possible inhibitory effect on the establishment of territories and use of space, thereby impacting on the reproductive behaviour of ostrich females and males in large flocks, respectively. This has important implications in terms of the intensification of ostrich farming especially in areas that are characterised by vegetation that is exposed to the trampling effect of ostriches.
South African Journal of Animal Science Vol.34(2) 2004: 87-9
Cytoplasmic PML promotes TGF-β-associated epithelial–mesenchymal transition and invasion in prostate cancer
Epithelial–mesenchymal transition (EMT) is a key event that is involved in the invasion and dissemination of cancer cells. Although typically considered as having tumour-suppressive properties, transforming growth factor (TGF)-β signalling is altered during cancer and has been associated with the invasion of cancer cells and metastasis. In this study, we report a previously unknown role for the cytoplasmic promyelocytic leukaemia (cPML) tumour suppressor in TGF-β signalling-induced regulation of prostate cancer-associated EMT and invasion. We demonstrate that cPML promotes a mesenchymal phenotype and increases the invasiveness of prostate cancer cells. This event is associated with activation of TGF-β canonical signalling pathway through the induction of Sma and Mad related family 2 and 3 (SMAD2 and SMAD3) phosphorylation. Furthermore, the cytoplasmic localization of promyelocytic leukaemia (PML) is mediated by its nuclear export in a chromosomal maintenance 1 (CRM1)-dependent manner. This was clinically tested in prostate cancer tissue and shown that cytoplasmic PML and CRM1 co-expression correlates with reduced disease-specific survival. In summary, we provide evidence of dysfunctional TGF-β signalling occurring at an early stage in prostate cancer. We show that this disease pathway is mediated by cPML and CRM1 and results in a more aggressive cancer cell phenotype. We propose that the targeting of this pathway could be therapeutically exploited for clinical benefit
Decision rules for determining terrestrial movement and the consequences for filtering high-resolution global positioning system tracks: a case study using the African lion ( Panthera leo )
The combined use of global positioning system (GPS) technology and motion sensors within the discipline of movement ecology has increased over recent years. This is particularly the case for instrumented wildlife, with many studies now opting to record parameters at high (infra-second) sampling frequencies. However, the detail with which GPS loggers can elucidate fine-scale movement depends on the precision and accuracy of fixes, with accuracy being affected by signal reception. We hypothesized that animal behaviour was the main factor affecting fix inaccuracy, with inherent GPS positional noise (jitter) being most apparent during GPS fixes for non-moving locations, thereby producing disproportionate error during rest periods. A movement-verified filtering (MVF) protocol was constructed to compare GPS-derived speed data with dynamic body acceleration, to provide a computationally quick method for identifying genuine travelling movement. This method was tested on 11 free-ranging lions (Panthera leo) fitted with collar-mounted GPS units and tri-axial motion sensors recording at 1 and 40 Hz, respectively. The findings support the hypothesis and show that distance moved estimates were, on average, overestimated by greater than 80% prior to GPS screening. We present the conceptual and mathematical protocols for screening fix inaccuracy within high-resolution GPS datasets and demonstrate the importance that MVF has for avoiding inaccurate and biased estimates of movement
Leadership and early strategic response to the SARS-CoV-2 pandemic at a COVID-19 designated hospital in South Africa
While many countries are preparing to face the COVID-19 pandemic, the reported cases in Africa remain low. With a high burden of both communicable and non-communicable disease and a resource-constrained public healthcare system, sub-Saharan Africa is preparing for the coming crisis as best it can. We describe our early response as a designated COVID-19 provincial hospital in Cape Town, South Africa (SA).While the first cases reported were related to international travel, at the time of writing there was evidence of early community spread. The SAgovernment announced a countrywide lockdown from midnight 26 March 2020 to midnight 30 April 2020 to stem the pandemic and save lives. However, many questions remain on how the COVID-19 threat will unfold in SA, given the significant informal sector overcrowding and poverty in our communities. There is no doubt that leadership and teamwork at all levels is critical in influencing outcomes
Adapt or die : the views of Unisa student teachers on teaching practice at schools
This study focuses on the views of Unisa distance education (DE) students enrolled for the
Postgraduate Certificate in Education (PGCE) who had completed their teaching practice.
The research questions were: What are student teachers’ experiences of the way in which
Unisa prepared them for teaching practice, the school context in which they practised
teaching, the mentoring they received or did not receive and the way they were assessed?
Socio-constructivist learning and situated learning theory were used as the theoretical
framework. A maximum variation sampling technique was used to select 16 participants
who had completed 10 weeks of teaching practice to participate in the study. Data were
collected by means of semi-structured interviews. The findings indicate that, in preparing
students for teaching practice, all role players need greater clarity on what is expected of
students with regard to learning outcomes, assessment criteria and lesson plans. Students
need to be placed at schools that will provide constructive learning environments, mentoring
teachers should receive training and there should be greater clarity on the who, what
and how of the assessment of students during teaching practice.Curriculum and Instructional Studie
Dead-reckoning animal movements in R: a reappraisal using Gundog.Tracks
BackgroundFine-scale data on animal position are increasingly enabling us to understand the details of animal movement ecology and dead-reckoning, a technique integrating motion sensor-derived information on heading and speed, can be used to reconstruct fine-scale movement paths at sub-second resolution, irrespective of the environment. On its own however, the dead-reckoning process is prone to cumulative errors, so that position estimates quickly become uncoupled from true location. Periodic ground-truthing with aligned location data (e.g., from global positioning technology) can correct for this drift between Verified Positions (VPs). We present step-by-step instructions for implementing Verified Position Correction (VPC) dead-reckoning in R using the tilt-compensated compass method, accompanied by the mathematical protocols underlying the code and improvements and extensions of this technique to reduce the trade-off between VPC rate and dead-reckoning accuracy. These protocols are all built into a user-friendly, fully annotated VPC dead-reckoning R function; Gundog.Tracks, with multi-functionality to reconstruct animal movement paths across terrestrial, aquatic, and aerial systems, provided within the Additional file 4 as well as online (GitHub).ResultsThe Gundog.Tracks function is demonstrated on three contrasting model species (the African lion Panthera leo, the Magellanic penguin Spheniscus magellanicus, and the Imperial cormorant Leucocarbo atriceps) moving on land, in water and in air. We show the effect of uncorrected errors in speed estimations, heading inaccuracies and infrequent VPC rate and demonstrate how these issues can be addressed.ConclusionsThe function provided will allow anyone familiar with R to dead-reckon animal tracks readily and accurately, as the key complex issues are dealt with by Gundog.Tracks. This will help the community to consider and implement a valuable, but often overlooked method of reconstructing high-resolution animal movement paths across diverse species and systems without requiring a bespoke application
Towards tailored teaching: using participatory action research to enhance the learning experience of Longitudinal Integrated Clerkship students in a South African rural district hospital
Background: The introduction of Stellenbosch University’s Longitudinal Integrated Clerkship (LIC) model as part of
the undergraduate medical curriculum offers a unique and exciting training model to develop generalist doctors
for the changing South African health landscape. At one of these LIC sites, the need for an improvement of the
local learning experience became evident. This paper explores how to identify and implement a tailored teaching
and learning intervention to improve workplace-based learning for LIC students.
Methods: A participatory action research approach was used in a co-operative inquiry group (ten participants),
consisting of the students, clinician educators and researchers, who met over a period of 5 months. Through a
cyclical process of action and reflection this group identified a teaching intervention.
Results: The results demonstrate the gaps and challenges identified when implementing a LIC model of medical
education. A structured learning programme for the final 6 weeks of the students’ placement at the district hospital
was designed by the co-operative inquiry group as an agreed intervention. The post-intervention group reflection
highlighted a need to create a structured programme in the spirit of local collaboration and learning across disciplines.
The results also enhance our understanding of both students and clinician educators’ perceptions of this new model
of workplace-based training.
Conclusions: This paper provides practical strategies to enhance teaching and learning in a new educational context.
These strategies illuminate three paradigm shifts: (1) from the traditional medical education approach towards
a transformative learning approach advocated for the 21st century health professional; (2) from the teaching
hospital context to the district hospital context; and (3) from block-based teaching towards a longitudinal
integrated learning model. A programme based on balancing structured and tailored learning activities is
recommended in order to address the local learning needs of students in the LIC model. We recommend
that action learning sets should be developed at these LIC sites, where the relevant aspects of work-place
based learning are negotiated
Longitudinal analyses of the DNA methylome in deployed military servicemen identify susceptibility loci for post-traumatic stress disorder
In order to determine the impact of the epigenetic response to traumatic stress on post-traumatic stress disorder (PTSD), this study examined longitudinal changes of genome-wide blood DNA methylation profiles in relation to the development of PTSD symptoms in two prospective military cohorts (one discovery and one replication data set). In the first cohort consisting of male Dutch military servicemen (n=93), the emergence of PTSD symptoms over a deployment period to a combat zone was significantly associated with alterations in DNA methylation levels at 17 genomic positions and 12 genomic regions. Evidence for mediation of the relation between combat trauma and PTSD symptoms by longitudinal changes in DNA methylation was observed at several positions and regions. Bioinformatic analyses of the reported associations identified significant enrichment in several pathways relevant for symptoms of PTSD. Targeted analyses of the significant findings from the discovery sample in an independent prospective cohort of male US marines (n=98) replicated the observed relation between decreases in DNA methylation levels and PTSD symptoms at genomic regions in ZFP57, RNF39 and HIST1H2APS2. Together, our study pinpoints three novel genomic regions where longitudinal decreases in DNA methylation across the period of exposure to combat trauma marks susceptibility for PTSD
- …