155 research outputs found

    Werkskepping in Botshabelo: Fiksie of feit

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    Research indicates that the labour force of Botshabelo has increased at a proportionally quicker rate than that of the RSA over a given period of time. This situation is however not an inherent characteristic of the economy of Botshabelo, but should be attrib­uted to factors such as, inter alia, an initial influx of people into the area, decentralisation incentives and the influence of commuter and migrant labour. The number of economically active persons who earn a living in Bot­shabelo is unacceptably low and it appears that the economy of the city as such is incapable of meeting the demand for local job opportunities. This can be attributed to inter alia a lack of linkage among industries, which is an indication of a poorly integrated economy. Planning for future growth and devel­opment in Botshabelo should occur within the context of development within the Bloemfontein-Botshabelo­Thaba Nchu (BBT) subregion. Any action which stimulates or inhibits the complementary nature of development in Bloemfontein, Botshabelo or Thaba Nchu, will have an influence on eco­nomic growth and development in Botshabelo.*This article is written in Afrikaans

    Induced gene expression in wheat seedlings treated with a crude extract of Agapanthus africanus L. prior to leaf rust infection

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    It was previously shown that a crude extract of Agapanthus africanus L. (Hoffman), applied as a foliar spray to wheat (Triticum aestivum L.) seedlings, significantly increased the in vitro activities of three pathogenesis related (PR) proteins (β-1,3-glucanase, chitinase and peroxidase). This was the case in both susceptible and resistant wheat lines whether the plants were uninfected or infected with leaf rust (Puccinia triticina). The aim of this study was to determine the influence of the A. africanus extract on both the intercellular PR-protein profile and PR gene expression in leaf rust infected wheat lines. Pretreatment of infected resistant and susceptible wheat with the extract led to increased β-1,3-glucanase levels that were higher as compared to the untreated controls. Similarly, treatment with the extract led to greater expression of both the PR3 and PR9 genes in infected resistant and susceptible seedlings as compared to the controls. This is also applied to a retrotransposon protein encoding gene whose expression was strongly induced following extract treatment. The induced expression of all these defence-related genes suggests that the crude A. africanus extract has the ability to prime the resistance response of wheat prior to leaf rust infection.Keywords: Wheat leaf rust, induced resistance, priming, gene expression, immunoblotting, crude Agapanthus africanus extractAfrican Journal of Biotechnology Vol. 12(20), pp. 2876-288

    Botshabelo: Reaksie van 'n tipiese slaapdorp op veranderende sosio-ekonomiese omstandighede in 'n "Nuwe Suid-Afrika“

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    Research has indicated that changing socio-economic conditions in a “New South Africa” have wide-reaching consequences in a “dormitory town ” such as Botshabelo. The purpose of this article is to determine which changes in respect of demographic and related aspects, as well as in the field of economics, have occurred in Bot­shabelo over a period of three years. A comparison of data obtained during surveys undertaken in 1988/89 and again in 1991 can throw light on changes which have occurred. As far as the demographic profile of the population is concerned, informa­tion was obtained during both the 1988/89 and 1991 surveys on a sample basis by means of personal interviews conducted within the community on the basis of interview schedules. During both surveys economic data was also obtained by means of interviews con­ducted with various enterprises on the basis of interview schedules. The tech­nique of input-output analysis was employed on both occasions to analyse the local economy. Aspects discussed in the article are estimated population size, factors influencing population growth, such as the composition and size of house­holds, age distribution o f the commu­nity, births and mortality, as well as expected future population growth. This is followed by a discussion of the performance of formal enterprises with regard to local sales, value added, import and exogenous demand, as well as of changes with regard to job op­portunities and work-place, distribu­tion of the labour force according to sector, the economically active popula­tion according to industry, sales and income of households.*This article is written in Afrikaans

    Visual parameter optimisation for biomedical image processing

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    Background: Biomedical image processing methods require users to optimise input parameters to ensure high quality output. This presents two challenges. First, it is difficult to optimise multiple input parameters for multiple input images. Second, it is difficult to achieve an understanding of underlying algorithms, in particular, relationships between input and output. Results: We present a visualisation method that transforms users’ ability to understand algorithm behaviour by integrating input and output, and by supporting exploration of their relationships. We discuss its application to a colour deconvolution technique for stained histology images and show how it enabled a domain expert to identify suitable parameter values for the deconvolution of two types of images, and metrics to quantify deconvolution performance. It also enabled a breakthrough in understanding by invalidating an underlying assumption about the algorithm. Conclusions: The visualisation method presented here provides analysis capability for multiple inputs and outputs in biomedical image processing that is not supported by previous analysis software. The analysis supported by our method is not feasible with conventional trial-and-error approaches

    Mutations in a Guanylate Cyclase GCY-35/GCY-36 Modify Bardet-Biedl Syndrome–Associated Phenotypes in Caenorhabditis elegans

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    Ciliopathies are pleiotropic and genetically heterogeneous disorders caused by defective development and function of the primary cilium. Bardet-Biedl syndrome (BBS) proteins localize to the base of cilia and undergo intraflagellar transport, and the loss of their functions leads to a multisystemic ciliopathy. Here we report the identification of mutations in guanylate cyclases (GCYs) as modifiers of Caenorhabditis elegans bbs endophenotypes. The loss of GCY-35 or GCY-36 results in suppression of the small body size, developmental delay, and exploration defects exhibited by multiple bbs mutants. Moreover, an effector of cGMP signalling, a cGMP-dependent protein kinase, EGL-4, also modifies bbs mutant defects. We propose that a misregulation of cGMP signalling, which underlies developmental and some behavioural defects of C. elegans bbs mutants, may also contribute to some BBS features in other organisms

    Risk and Ethical Concerns of Hunting Male Elephant: Behavioural and Physiological Assays of the Remaining Elephants

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    BACKGROUND: Hunting of male African elephants may pose ethical and risk concerns, particularly given their status as a charismatic species of high touristic value, yet which are capable of both killing people and damaging infrastructure. METHODOLOGY/PRINCIPAL FINDINGS: We quantified the effect of hunts of male elephants on (1) risk of attack or damage (11 hunts), and (2) behavioural (movement dynamics) and physiological (stress hormone metabolite concentrations) responses (4 hunts) in Pilanesberg National Park. For eleven hunts, there were no subsequent attacks on people or infrastructure, and elephants did not break out of the fenced reserve. For three focal hunts, there was an initial flight response by bulls present at the hunting site, but their movements stabilised the day after the hunt event. Animals not present at the hunt (both bulls and herds) did not show movement responses. Physiologically, hunting elephant bulls increased faecal stress hormone levels (corticosterone metabolites) in both those bulls that were present at the hunts (for up to four days post-hunt) and in the broader bull and breeding herd population (for up to one month post-hunt). CONCLUSIONS/SIGNIFICANCE: As all responses were relatively minor, hunting male elephants is ethically acceptable when considering effects on the remaining elephant population; however bulls should be hunted when alone. Hunting is feasible in relatively small enclosed reserves without major risk of attack, damage, or breakout. Physiological stress assays were more effective than behavioural responses in detecting effects of human intervention. Similar studies should evaluate intervention consequences, inform and improve best practice, and should be widely applied by management agencies

    Genetic variability and ontogeny predict microbiome structure in a disease-challenged montane amphibian

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    Amphibian populations worldwide are at risk of extinction from infectious diseases, including chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian cutaneous microbiomes interact with Bd and can confer protective benefits to the host. The composition of the microbiome itself is influenced by many environment- and host-related factors. However, little is known about the interacting effects of host population structure, genetic variation and developmental stage on microbiome composition and Bd prevalence across multiple sites. Here we explore these questions in Amietia hymenopus, a disease-affected frog in southern Africa. We use microsatellite genotyping and 16S amplicon sequencing to show that the microbiome associated with tadpole mouthparts is structured spatially, and is influenced by host genotype and developmental stage. We observed strong genetic structure in host populations based on rivers and geographic distances, but this did not correspond to spatial patterns in microbiome composition. These results indicate that demographic and host genetic factors affect microbiome composition within sites, but different factors are responsible for host population structure and microbiome structure at the between-site level. Our results help to elucidate complex within- and among- population drivers of microbiome structure in amphibian populations. That there is a genetic basis to microbiome composition in amphibians could help to inform amphibian conservation efforts against infectious diseases

    MRI of the kidney—state of the art

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    Ultrasound and computed tomography (CT) are modalities of first choice in renal imaging. Until now, magnetic resonance imaging (MRI) has mainly been used as a problem-solving technique. MRI has the advantage of superior soft-tissue contrast, which provides a powerful tool in the detection and characterization of renal lesions. The MRI features of common and less common renal lesions are discussed as well as the evaluation of the spread of malignant lesions and preoperative assessment. MR urography technique and applications are discussed as well as the role of MRI in the evaluation of potential kidney donors. Furthermore the advances in functional MRI of the kidney are highlighted

    Visual inspection with acetic acid as a cervical cancer test: accuracy validated using latent class analysis

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to validate the accuracy of an alternative cervical cancer test – visual inspection with acetic acid (VIA) – by addressing possible imperfections in the gold standard through latent class analysis (LCA). The data were originally collected at peri-urban health clinics in Zimbabwe.</p> <p>Methods</p> <p>Conventional accuracy (sensitivity/specificity) estimates for VIA and two other screening tests using colposcopy/biopsy as the reference standard were compared to LCA estimates based on results from all four tests. For conventional analysis, negative colposcopy was accepted as a negative outcome when biopsy was not available as the reference standard. With LCA, local dependencies between tests were handled through adding direct effect parameters or additional latent classes to the model.</p> <p>Results</p> <p>Two models yielded good fit to the data, a 2-class model with two adjustments and a 3-class model with one adjustment. The definition of latent disease associated with the latter was more stringent, backed by three of the four tests. Under that model, sensitivity for VIA (abnormal+) was 0.74 compared to 0.78 with conventional analyses. Specificity was 0.639 versus 0.568, respectively. By contrast, the LCA-derived sensitivity for colposcopy/biopsy was 0.63.</p> <p>Conclusion</p> <p>VIA sensitivity and specificity with the 3-class LCA model were within the range of published data and relatively consistent with conventional analyses, thus validating the original assessment of test accuracy. LCA probably yielded more likely estimates of the true accuracy than did conventional analysis with in-country colposcopy/biopsy as the reference standard. Colpscopy with biopsy can be problematic as a study reference standard and LCA offers the possibility of obtaining estimates adjusted for referent imperfections.</p
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