4,407 research outputs found

    Names of fungal species with the same epithet applied to different morphs: how to treat them

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    The abolition of the separate naming of different morphs of the same fungal species in 2011 will inevitably result in many name changes in some genera. The working practices commended here are intended to minimize one category of these changes, that which can arise as a consequence of an author using the epithet of an asexual morph when describing the sexual morph of the same species. We consider that name proposed for the sexual morph in such cases should be treated as a formal error for a new combination and not as a new species, and so be corrected. This is interpreted as applying even where the author indicated that a new species was being described and designated a type. We argue that those formalities were a result of the requirements of the rules then in force, as the author recognized that a morph of a named species was being described, and not a new hitherto unnamed species was being reported - but was barred from making a new combination so used the same epithet for the new morph name instead. Where a type with the sexual morph was designated for the sexual morph, under this interpretation that no longer has nomenclatural status, the type being that of the basionym. The material for the sexual morph indicated as a type, would be available for designation as an epitype, though a modern sequenced sample with both sexual and asexual morphs would be more informative as an epitype in many cases. A proposal to regularize the working practice commended here, and also the converse situation where the sexual morph typified name is the earlier, will be made to the 2017 Shenzhen Congress

    Improving the livelihoods of wool producers in a sustainable manner by optimizing the woolled sheep production systems within the communal farming area of the Eastern Cape. “A vision that is future directed”

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    The main objective of the NWGA is to improve both the quality and quantity of wool produced in the communal wool sheep farming areas of South Africa. Shearing sheds in the communal area were divided into three performance categories namely top, average and bottom sheds. This finding has led to two questions: Why and where do they differ? Can something be done to improve the performance of the sheds? A total of five (5) top, five (5) average and seven (7) bottom sheds were selected to collect data from 179 respondents. The socio-economic data is always important to indicate clearly who the respondents are. The average age of respondents is 59.46 and 64% male and 36% females. There are more members in the top sheds than in the other two categories. Although a large number of respondents can read and write, the majority do have only a qualification at the lower level. A total of 83% of the respondents do have some years of experience in sheep farming. Respondents in the top shed have significantly more sheep, cattle and goats than respondents in the average and bottom sheds. Significantly more farmers attend the top shed meetings than farmer members in the other two categories. A total of 39% respondents indicated that good sheep health control will lead to higher wool production and the most common diseases as perceived by respondents are Sheep scab, Blue tongue and internal parasites. Burr/weeds and paints are the two most important objects of wool contamination. Significantly more sheep are sheared in the top sheds, they pack more bales and the weight of the bales is higher than in the average and bottom sheds. Farmer’s most important needs are financial issues, farm infrastructure and they need more land. To improve the profitability and productivity of wool sheep farming at all shearing sheds within the communal farming area. A specific extension program addressing the specific needs will be presented to farmers in each of the three shearing shed groups.Keywords: communal wool sheep farmers, farmer’s needs, perception, knowledge, extension progra

    Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy

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    We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (<5 mu M). Aerobic chemolithotrophic activity of the SOB depended entirely on oxygen produced locally by cyanobacteria during high light conditions. In contrast, B/C mats formed at locations where oxygen in the water column was comparatively abundant (445 mu M) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater

    Fine‐scale measurement of diffusivity in a microbial mat with nuclear magnetic resonance imaging

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    Noninvasive 1H‐nuclear magnetic resonance (NMR) imaging was used to investigate the diffusive properties of microbial mats in two dimensions. Pulsed field gradient NMR was used to acquire images of the H2O diffusion coefficient, Ds, and multiecho imaging NMR was used to obtain images of the water density in two structurally different microbial mats sampled from Solar Lake (Egypt). We found a pronounced lateral and vertical variability of both water density and water diffusion coefficient, correlated with the laminated and heterogeneous distribution of microbial cells and exopolymers within the mats. The average water density varied from 0.5 to 0.9, whereas the average water diffusion coefficient ranged from 0.4 to 0.9 relative to the values obtained in the stagnant water above the mat samples. The apparent water diffusivities estimated from NMR imaging compared well to apparent O2 diffusivities measured with a diffusivity microsensor. Analysis of measured O2 concentration profiles with a diffusion‐reaction model showed that both the magnitude of calculated rates and the depth distribution of calculated O2 consumption/production zones changed when the observed variations of diffusivity were taken into account. With NMR imaging, diffusivity can be determined at high spatial resolution, which can resolve inherent lateral and vertical heterogeneities found in most natural benthic systems

    #Feesmustfall and beyond: Towards a sustainable national student loan regulatory framework

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    Universities have been forced to raise higher education fees with above inflation rates due to increasing operating costs and higher student numbers and decreasing real term government funding. While free higher education or other alternative funding models are being considered, the higher education sector is at stake: a sector that plays a vital role in creating improved lives for all South Africans. A sustainable framework is desperately required or universities will once again need to increase student fees at unreasonable rates to maintain quality. We therefore performed a mixed method documentary analysis to prove that fee-free higher education is not viable in South Africa as significant funds will either need to be reallocated from other sectors that also require funding, or it will have to be collected from already overburdened tax payers. The present study also developed a viable student fee regulatory framework with the use of grounded theory: subsidised higher education with the effective use of the already implemented National Student Financial Aid Scheme

    Predicting work performance through selection interview ratings and psychological assessment.

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    The aim of the study was to establish whether selection interviews used in conjunction with psychological assessments of personality traits and cognitive functioning contribute to predicting work performance. The sample consisted of 102 managers who were appointed recently in a retail organisation. The independent variables were selection interview ratings obtained on the basis of structured competency-based interview schedules by interviewing panels, five broad dimensions of personality defined by the Five Factor Model as measured by the 15 Factor Questionnaire (15FQ+), and cognitive processing variables (current level of work, potential level of work, and 12 processing competencies) measured by the Cognitive Process Profile (CPP). Work performance was measured through annual performance ratings that focused on measurable outputs of performance objectives. Only two predictor variables correlated statistically significantly with the criterion variable, namely interview ratings (r = 0.31) and CPP Verbal Abstraction (r = 0.34). Following multiple regression, only these variables contributed significantly to predicting work performance, but only 17.8% of the variance of the criterion was accounted for

    A Killing Disease Epidemic Among Displaced Sudanese Population Identified as Visceral Leishmaniasis.

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    A fatal disease epidemic affected the Bentiu area in southern Sudan and led to a mass migration of the Nuer tribe searching for treatment. The initially available information revealed a high mortality rate due to a possible occurrence of tuberculosis, malaria, enteric fever or visceral leishmaniasis (VL). Serological screening of 53 of the most severely affected patients in an enzyme-linked immunosorbent assay (ELISA) or an improved direct agglutination test (DAT) revealed positivity for VL. In 39 of those patients, diagnosis was confirmed by identification of Leishmania donovani amastigotes in lymph node or bone-marrow aspirates. In a total of 2714 patients observed, 1195 (44.0%) had clinical symptoms suggesting VL: DAT positive titers (1:3200-greater than or equal to 1:12800) were obtained in 654 (24.1%), of whom 325 were confirmed parasitologically. Forty-two VL cases died before or during treatment, giving a mortality rate of 6.4%. Among the intercurrent infections diagnosed in the VL population (654), respiratory involvements (31.7%) and malaria (10.7%) were most prevalent. With the exception of four (0.6%), all other VL patients (509) responded readily to sodium stibogluconate. The factors initiating the outbreak are discussed. Malnutrition and nomadic movements to potential VL endemic areas appeared to be the most important. HIV infection as a possible predisposition seemed remote considering the clinical and epidemiological similarity to VL occurring in East Africa, adequate humoral response in DAT, and immediate positive response to specific anti-Leishmania chemotherapy

    Postmortem tissue distribution of morphine and its metabolites in a series of heroin related deaths

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    The abuse of heroin (diamorphine) and heroin deaths are growing around the world. The interpretation of the toxicological results from suspected heroin deaths is notoriously difficult especially in cases where there may be limited samples. In order to help forensic practitioners with heroin interpretation we determined the concentration of morphine (M), morphine‐3‐glucuronide (M3G) and morphine‐6‐glucuronide (M6G) in blood (femoral and cardiac), brain (thalamus), liver (deep right lobe), bone marrow (sternum), skeletal muscle (psoas) and vitreous humor in 44 heroin related deaths. The presence of 6‐monoacetylmorphine (6‐MAM) in any of the postmortem samples was used as confirmation of heroin use. Quantitation was carried out using a validated LC‐MS/MS method with solid phase extraction. We also determined the presence of papaverine, noscapine and codeine in the samples, substances often found in illicit heroin and that may help determine illicit heroin use. The results of this study show that vitreous is the best sample to detect 6‐MAM (100% of cases), and thus heroin use. The results of the M, M3G and M6G quantitation in this study allow a degree of interpretation when samples are limited. However in some cases it may not be possible to determine heroin/morphine use as in 4 cases in muscle (3 cases in bone marrow) no morphine, morphine‐3‐glucuronide or morphine‐6‐glucuronide was detected, even though they were detected in other case samples. As always postmortem cases of suspected morphine/heroin intoxication should be interpreted with care and with as much case knowledge as possible
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