103 research outputs found

    Afdankings weens operasionele vereistes : brug of afgrond

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    no abstract availableJurisprudenceM.A. (Spesialisering in Arbeidsreg

    Burrow architecture of the Damaraland mole-rat (Fukomys damarensis) from South Africa

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    The burrow architecture (length, internal dimensions, fractal dimension of tunnel systems, number of nesting chambers and surface mounds) was investigated in the Damaraland mole-rat (Fukomys damarensis). A total of 31 animals were caught from five different colonies and their burrow systems were excavated in their entirety. The mean and SD colony size was 6 ± 3.3, with a range of 2-10 mole-rats. The sex ratio was male biased 1.21:1. Males had a body mass of 80.5 ± 33.8g, but were not significantly different to those of females which had a mean body mass of 83.4 ± 24.9g. The burrow system of the Damaraland mole-rats follows the same general architectural plan as recorded for other species of mole-rat with either one or two more centrally based deeper more permanent burrows which often connect to a nest area, which is used for resting and rearing offspring. The burrow systems contained several more superficial secondary tunnels at a shallower depth. The secondary tunnels accounted for up to 80% of the total burrow system. The mean length of the burrow system was 130.4m and covered an area of 1403m². The mean number of secondary branches in a burrow system was 10. The mean fractal dimension was 1.154 which implies the mole-rats do not explore their surrounding environment particularly efficiently when compared to that of other mole-rat species, but this may relate to the size of the main food resource, the Eland bean (Elephantorrhiza elephantina) which is randomly distributed and fed on in situ. Our study showed that colony size influences the size and complexity of the burrow system with larger colonies having a longer burrow system covering a greater area with more secondary tunnels than that of smaller colonies.The University of Pretoria, by the SARChI Chair of Mammal Behavioural Ecology and Physiology and by the National Research Foundation, South Africa to NCB.http://www.nisc.co.za/products/59/journals/african-zoology2017-04-30hb2016Zoology and Entomolog

    Using participatory videos in understanding farmers experiences with climate smart agricultural practices: reflections from Ghana

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    Climate-smart agriculture (CSA) has gained traction as one of the effective strategies in tackling the climate crisis. Many CSA practices have been promoted by development agencies to smallholder farmers based on the assumption that farmers would adopt these innovations for their potential benefits. However, the adoption of CSA practices in Ghana and much of Africa remains low and decision making and on-farm innovation processes are poorly understood. This study seeks to provide empirical and participatory insight into how smallholder farmers innovate. Based on a novel application of a participatory video methodology, in farming communities in the Upper West Region of Ghana, that have been exposed to multiple CSA intervention programmes, the paper analyses farmers’ own self-curated accounts of experiences with CSA innovation. The findings show that farmer’s motivation to adopt CSA innovations is driven by their concerns for food security, economic gains, and the environmental impact of climate change on their farming activities and livelihood. The study reveals a mismatch between the CSA technologies and practices advanced by the development agencies and what farmers perceive as relevant and important in addressing their farming challenges. In particular, the findings show that in a pool of more than 12 CSA technologies and practices that had been promoted through three donor-driven intervention programmes in the communities, farmers selected less labour intensive, less costly, and CSA technologies and practices that fitted to their current farming practices and the local context. Agricultural extension agents served as an important information source on the CSA innovation and their practical implementation and farmers’ social groups played a crucial role in facilitating learning about the CSA technologies and practices. There is the need to integrate farmers voices using innovative methodologies such as participatory videos to better understand farmers’ experiences in the innovation process which will help inform the design of effective interventions and promote adoption of innovations aimed at enhancing the productivity of smallholder farmers and reducing environmental impacts in African food systems. By focusing on the innovations that farmers perceive as beneficial and adaptable to their local contexts, development organizations can use their resources more efficiently and promote adoption of contextually appropriate CSA innovations

    Seasonal changes in burrow geometry of the common mole rat (Rodentia: Bathyergidae)

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    Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group.The University of Pretoria, by the SARChI Chair of Mammal Behavioural Ecology and Physiology and by the National Research Foundation, South Africa to NCB.http://link.springer.com/journal/114hj201

    The feasibility of canine rabies elimination in Africa: dispelling doubts with data

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    <p><b>Background:</b> Canine rabies causes many thousands of human deaths every year in Africa, and continues to increase throughout much of the continent.</p> <p><b>Methodology/Principal Findings:</b> This paper identifies four common reasons given for the lack of effective canine rabies control in Africa: (a) a low priority given for disease control as a result of lack of awareness of the rabies burden; (b) epidemiological constraints such as uncertainties about the required levels of vaccination coverage and the possibility of sustained cycles of infection in wildlife; (c) operational constraints including accessibility of dogs for vaccination and insufficient knowledge of dog population sizes for planning of vaccination campaigns; and (d) limited resources for implementation of rabies surveillance and control. We address each of these issues in turn, presenting data from field studies and modelling approaches used in Tanzania, including burden of disease evaluations, detailed epidemiological studies, operational data from vaccination campaigns in different demographic and ecological settings, and economic analyses of the cost-effectiveness of dog vaccination for human rabies prevention.</p> <p><b>Conclusions/Significance:</b> We conclude that there are no insurmountable problems to canine rabies control in most of Africa; that elimination of canine rabies is epidemiologically and practically feasible through mass vaccination of domestic dogs; and that domestic dog vaccination provides a cost-effective approach to the prevention and elimination of human rabies deaths.</p&gt

    Treatment of Marburg and Ebola hemorrhagic fevers: A strategy for testing new drugs and vaccines under outbreak conditions.

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    The filoviruses, Marburg and Ebola, have the dubious distinction of being associated with some of the highest case-fatality rates of any known infectious disease-approaching 90% in many outbreaks. In recent years, laboratory research on the filoviruses has produced treatments and vaccines that are effective in laboratory animals and that could potentially drastically reduce case-fatality rates and curtail outbreaks in humans. However, there are significant challenges in clinical testing of these products and eventual delivery to populations in need. Most cases of filovirus infection are recognized only in the setting of large outbreaks, often in the most remote and resource-poor areas of sub-Saharan Africa, with little infrastructure and few personnel experienced in clinical research. Significant political, legal, and socio-cultural barriers also exist. Here, we review the present research priorities and environment for field study of the filovirus hemorrhagic fevers and outline a strategy for future prospective clinical research on treatment and vaccine prevention

    Risk Factors for Marburg Hemorrhagic Fever, Democratic Republic of the Congo

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    We conducted two antibody surveys to assess risk factors for Marburg hemorrhagic fever in an area of confirmed Marburg virus transmission in the Democratic Republic of the Congo. Questionnaires were administered and serum samples tested for Marburg-specific antibodies by enzyme-linked immunosorbent assay. Fifteen (2%) of 912 participants in a general village cross-sectional antibody survey were positive for Marburg immunoglobulin G antibody. Thirteen (87%) of these 15 were men who worked in the local gold mines. Working as a miner (odds ratio [OR] 13.9, 95% confidence interval [CI] 3.1 to 62.1) and receiving injections (OR 7.4, 95% CI 1.6 to 33.2) were associated with a positive antibody result. All 103 participants in a targeted antibody survey of healthcare workers were antibody negative. Primary transmission of Marburg virus to humans likely occurred via exposure to a still unidentified reservoir in the local mines. Secondary transmission appears to be less common with Marburg virus than with Ebola virus, the other known filovirus

    Nomenclature- and Database-Compatible Names for the Two Ebola Virus Variants that Emerged in Guinea and the Democratic Republic of the Congo in 2014

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    In 2014, Ebola virus (EBOV) was identified as the etiological agent of a large and still expanding outbreak of Ebola virus disease (EVD) in West Africa and a much more confined EVD outbreak in Middle Africa. Epidemiological and evolutionary analyses confirmed that all cases of both outbreaks are connected to a single introduction each of EBOV into human populations and that both outbreaks are not directly connected. Coding-complete genomic sequence analyses of isolates revealed that the two outbreaks were caused by two novel EBOV variants, and initial clinical observations suggest that neither of them should be considered strains. Here we present consensus decisions on naming for both variants (West Africa: “Makona”, Middle Africa: “Lomela”) and provide database-compatible full, shortened, and abbreviated names that are in line with recently established filovirus sub-species nomenclatures
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