1834 research outputs found
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Out of control: profit-seeking behaviour, unnecessary medical procedures and rising costs of private medical care in South Africa
No full textThe World Health Assembly passed a resolution on the importance of engaging with the private health sector. However, the reality is that universal health coverage aspirations are particularly challenging when there is a significant private health sector. This sector in South Africa suffers from rapidly increasing costs, inflation and volume of services (unnecessary medical tests or treatments). This commentary draws on the international literature, particularly the Japanese model of healthcare, to illustrate that it is necessary and possible to curtail costs and volume in the private sector in South Africa, and possibly in other low-income and middle-income settings.National Research Foundation (South Africa
Obituary: Martin Legassick
No full textIn the hours following the announcement of Martin Legassick’s passing, scores of messages of condolences streamed in from across the world. Written by activists, former students, professors and workers, they contained a common thread: he was an exemplary scholar and committed socialist activistNational Research Foundation (South Africa
Plant-produced Crimean-Congo haemorrhagic fever virus nucleoprotein for use in ELISA
No full textCrimean-Congo haemorrhagic fever (CCHF) is a disease of serious public concern caused by the CCHF virus (CCHFV). Anti-CCHFV IgG in humans can be detected using ELISA with native antigen prepared from cell cultures which have been infected with virus or from brain tissue of suckling mice which have been inoculated with virus. However, the preparation of these reagents requires high biosafety levels and is expensive. A safer, more cost-effective recombinantly-produced NP reagent is desirable. Recently, plants have been shown to be a cost-effective and safe system for expression of recombinant proteins. This work describes cloning of the CCHFV NP gene into three different plant expression systems and comparison of expression in Nicotiana benthamiana. The highest expressing construct was selected. Expressed NP was purified by ammonium sulphate fractionation prior to histidine affinity chromatography. Purified NP was tested in an indirect ELISA to determine if the recombinant antigen was able to detect anti-CCHFV IgG in sera from convalescent patients. Plant-produced NP detected IgG antibodies against CCHFV in 13/13 serum samples from convalescent patients and 0/13 samples collected from volunteers with no history of CCHFV infection. Results were compared with commercially available immunofluorescent assays and 100% concordance was obtained between the two assays. This suggests that a full evaluation of the plant produced NP for application as a safe recombinant is warrantedNational Research Foundation (South Africa
Predictors of mammal species richness in KwaZulu-Natal, South Africa
No full textThe management of multi-functional landscapes warrants better knowledge of environment-richness associations at varying disturbance levels and habitat gradients. Intensive land-use patterns for agricultural purposes lead to fragmentation of natural habitat resulting in biodiversity loss that can be measured using landscape metrics to assess mammalian richness. Since carnivores and herbivores are likely to show different responses to disturbance, we calculated carnivore, non-carnivore, and total mammal species richness from camera surveys using a first order Jackknife Estimator. Richness was compared along a habitat gradient comprising coastal forest, Acacia thicket, and highland in KwaZulu-Natal, South Africa. We used standardized OLS regression models to identify climatic and disturbance variables, and landscape metrics as predictors of species richness. The estimated total and non-carnivore species richness were highest in coastal forest, while carnivore species richness was highest in highland followed by coastal forest and Acacia thicket. Average monthly maximum temperature was a significant predictor of all richness groups, and precipitation of the wettest month and isothermality determined total and non-carnivore species richness, respectively. These climatic variables possibly limit species distribution because of physiological tolerance of the species. Total mammal richness was determined by mean shape (+) and habitat division (−) while diversity (+) and patch richness (−) explained carnivore species richness. Mean shape index (+) influenced non-carnivore richness. However, habitat division and patch richness negatively influenced total mammal richness. Though habitat patch size and contiguity had a weak positive prediction, these metrics demonstrated the importance of habitat connectivity for maintaining mammal richness. The identification of these climatic and landscape patterns is important to facilitate future landscape management for mammal conservation in forest-mosaicsNational Research Foundation (South Africa
Native habitat and Protected Area size matters: Preserving mammalian assemblages in the Maputaland Conservation Unit of South Africa.
No full textIdentifying unique habitats that support intact mammal assemblages help to prioritize conservation areas. Over time, modifications of native habitats in multi-functional Protected Areas (PAs) can drive changes in mammal populations. We assessed mammalian richness across PA sizes and multi-species occupancy in various habitats, including plantations, in the Maputaland Conservation Unit, South Africa. We collected data from six camera-trap surveys (205 camera-trap stations) between 2013 and 2014 covering PAs that varied in size, habitat diversity and disturbance levels. We included eight habitat covariates for occupancy estimation and narrow vs. wider path as detection covariates. We applied the Royle–Nichols multi-session multi-species hierarchical model to estimate species richness and occupancy dynamics of 39 mammalian species for different PAs, while accounting for imperfect detection. Species richness increased with protected area size. Most large mammals were absent in the smallest PA. Detection probabilities for 90% of the species were <0.10 and showed considerable species-specific detection rates on both narrow and wide paths. High occupancy (>0.40) was estimated for 16 species in grassland and plantation, followed by woodland (15), sand forest (14), coastal lowland forest and dune forests (13 species each), Makatini clay thicket (12) and dry forest thicket (10). Plantation had higher mammal occupancy, presumably attributed to the edge effects of adjacent natural habitats, and the understory grass cover in abandoned and immature plantations. Our findings provided comprehensive inferences on community-wide assemblages for valuable management decision making.National Research Foundation (South Africa
Non-singular terminal sliding mode controller: Application to an actuated exoskeleton
No full textThis paper presents a robust controller of an active orthosis used for rehabilitation purposes. The system is composed of the orthosis worn by the shank and has a complex dynamical model. No prior knowledge is considered on the dynamical model and the flexion/extension movements considered are of sinusoidal form and are generally defined by the doctor. The used non-singular terminal sliding mode technique permits to have a finite time convergence. The experimental results have been conducted online on an appropriate dummy and then on three healthy subjects. A comparison of performances obtained by the proposed approach with those obtained by a conventional controller has also been realized. Several situations have been considered to test the robustness and it has been concluded with the effectiveness of the developed controller.National Research Foundation (South Africa
First record of a non-pollinating fig wasp (Hymenoptera: Sycophaginae) from Dominican amber, with estimation of the size of its host figs
No full textFig trees and their pollinating fig wasps arose about 75 million years ago in the Cretaceous period. Several other groups of chalcid wasps also utilize figs for larval development, including sycophagines, the putative sister group to pollinating fig wasps. Whereas stone and amber fossil pollinators are known, no fossils representing non-pollinating fig wasp groups have been confirmed previously. Here, we describe the first Sycophaginae from the c.15–20 Ma Dominican amber, Idarnes thanatos sp. nov. Farache, Rasplus, Pereira and Compton, and discuss its relationships within the Idarnes carme species group. Additionally, we use linear regression to compare body size, ovipositor sheaths length, and host fig size data from extant Idarnes species to estimate the size of its host figs. Idarnes thanatos was most likely associated with small to medium sized figs (diameter ≤1.0 cm), that were likely to have been dispersed by birds and primates. The discovery of this close relative of extant non-pollinating fig wasps suggests that early Miocene and modern fig wasp communities may share similar ecological and functional features.National Research Foundation (South Africa
Progress towards eradication of Rhododendron ponticum on Lundy
No full textControl of rhododendron on Lundy accelerated from the 1990s after recruitment of specialist climbers and a ranger. Rhododendron's ‘Achilles heel’ is a lack of a persistent seed bank and long-term prevention of flowering is therefore key to eventual eradication. Larger rhododendrons have now all been cut and herbicide-treated and any remaining plants that flower are targeted for rapid removal. No individuals are believed to have set seed for about four years and the number of plants that remain alive is being reduced each year. Eradication is now achievable if vigilance can be maintained each year for a least another decadeNational Research Foundation (South Africa
Temporal and interspecific variation in rates of spread for insect species invading Europe during the last 200 years
No full textGlobalization is triggering an increase in the establishment of alien insects in Europe, with several species having substantial ecological and economic impacts. We investigated long-term changes in rates of species spread following establishment. We used the total area of countries invaded by 1171 insect species for which the date of first record in Europe is known, to estimate their current range radius (calculated as [invaded area]0.5/π). We estimated initial rates of radial spread and compared them among different groups of insects for all years (1800–2014) and for a subset of more recent decades (1950–2014). Accidentally introduced species spread faster than intentionally introduced species. Considering the whole period 1800–2014, spread patterns also differ between feeding guilds, with decreasing spread rates over residence time in herbivores but not in detritivores or parasitic species. These decreases for herbivorous species appeared mainly in those associated with herbaceous plants and crops rather than woody plants. Initial spread rate was significantly greater for species detected after 1990, roughly 3–4 times higher than for species that arrived earlier. We hypothesize that the political changes in Europe following the collapse of the Iron Curtain in 1989, and the further dismantling of customs checkpoints within an enlarged European Union (EU) have facilitated the faster spread of alien insect species. Also, the number of species first recorded in the Eastern Bloc of the politically-divided Europe before 1989 was lower than for the rest of Europe. A detailed analysis of six recent invaders indicated a dominant role of long-distance translocations related to human activities, especially with the plant trade, in determining rates of spread.National Research Foundation (South Africa
Methods and approaches for the management of arthropod border incursions
No full textBiological invasions are increasing and are strongly associated with negative agricultural, economic and ecological impacts. It is increasingly recognized that the primary focus in minimizing biological invasions should be to prevent initial entry of alien species. However, exclusion of terrestrial arthropods such as insects and mites is difficult, in part because of their relatively small size, cryptic habits, broad physiological tolerances and close association with various internationally traded goods. Here we discuss methods, approaches, management and intervention systems used by border biosecurity agencies to prevent entry of inadvertently transported arthropods. We examine the at-border systems that exist for the detection and identification of and response to alien arthropods, and discuss the constraints and challenges present in these systems. We critically review current border biosecurity systems and discuss their relative efficacy. We then discuss additional measures and key areas that could be addressed that may further improve these systems. These include: (1) the application of appropriate sampling strategies; (2) employment of suitable inspection methods adequate to detect small and hidden arthropods; and (3) thorough recording of methods, organisms detected and both negative and positive results of inspections. We emphasize that more research is needed on taxonomy, biology, genetics, distribution, host and disease associations, impacts and pathways of introductions for invasive arthropods. Of critical importance is the compilation of complete and accurate invasive species lists and high-risk species watch-lists. The adoption of these recommendations will contribute to improved biosecurity systems for the exclusion of alien, invasive and pest arthropods.National Research Foundation (South Africa