99 research outputs found

    An estimate of poaching in Area 5 using comparative catches between days of no compliance operations and when a patrol vessel was present

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    Based on differences in trap catches from days with and without a patrol boat present, the annual theft by poaches from commercial traps in Area 5 is estimated to be 140 tons. For a 16 day period (covering 6 January 2015 -28 January 2015) catches were recorded in Area 5 (sub areas 1 and 2 – North Blinder and Brittania Blinder). During this period no compliance operations took place i.e. no patrol boat was operating in the area. It is known that a common poaching practice is for the poachers to operate at night removing lobsters from the commercial traps. Catches were similarly recorded for a two-day period (29-30 January 2015) when a patrol boat was present in the area – preventing poaching operations. Catches are also available for a longer time period (25/11/14-23/02/15) though this period includes the period of walkouts (after which catches dropped), and can be extracted for the period 25/11/14-28/01/15 which is before the period of the walkouts. Table 1 reports the resultant catch statistics obtained from the commercial trap fishery during these periods

    Analysis of the microbial community associated with a bioprocess system for bioremediation of thiocyanate- and cyanide-laden mine water effluents

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    Gold extraction by cyanidation from refractory gold ores results in the formation of thiocyanate- and cyanide-contaminated wastewater effluents that must be treated before recycle or discard. Activated sludge processes, such as ASTERâ„¢, can be used for biodegradation of these effluent streams. The destruction of these compounds is catalyzed by a mixed microbial culture, however, very little is known about the community composition and metabolic potential of the thiocyanate- and cyanide-degrading microorganisms within the community. Here we describe our on-going attempts to better understand the key microorganisms, within the ASTERâ„¢ bioprocess, that contribute to the destruction of thiocyanate and cyanide, and how this knowledge relates to further process optimisation

    (Un)reliable assessment : A case study.

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    The drive towards quality assurance at South African universities, with 'consistency' of approach being one of its key features, has profound implications for assessment policies and practices in relation to equity. In this article we present a case study discussion of an investigation we undertook, as a department, into certain anomalies which arose in the assessment of a particular group of post-graduate students' research reports. We were puzzled by the variability in the marks awarded by three different markers of the same reports and set out to investigate what factors were producing this 'inter-marker [un]reliability'. Through a content and discourse analysis of the different assessors' written reports, we uncovered the implicit assessment categories and criteria which assessors were working with in their assessments. We discovered shared categories and criteria, as well as differences in how these were weighted. In the interests of equity and increased inter-marker reliability, we have developed a set of banded criteria on generic features of the research report which we intend to develop a set of banded criteria on generic features of the research report which we intend to trial. We also surfaced two unresolved issues: the use of language and the role of the writer's 'voice' in the research report. As a result of this investigation, we argue that the 'consistency' of assessment within and across universities aspired to by quality assurers (such as the HEQC in the South African context) is difficult to achieve and much still depends on professional judgement, intellectual position and personal taste

    A new model for the pathophysiology of Alzheimer's disease: Aluminium toxicity is exacerbated by hydrogen peroxide and attenuated by an amyloid protein fragment and melatonin

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    Objectives. Although Alzheimer's disease (AD) is the leading cause of dementia in developed countries, there is an as yet unexplained lower prevalence of the disease in parts of Africa. AD is characterised by a catastrophic loss of neurons; free radicals (oxidative toxins) have been implicated in the destruction of the cells through the process of lipid peroxidative damage of cell membranes. Previously aluminium (Al) and a fragment of beta amyloid (Aβ 25 - 35) were shown to exacerbate tree-radical damage, while melatonin reduced this effect. The aim of the present study was: (i) to investigate the conditions detennining the toxicity of Al and Aβ 25 - 35; and (ii) to assess whether melatonin could attenuate the damage done by both aluminium and the amyloid fragment, thus suggesting a pathway for the aetiology of AD.Design. An in vitro model system was used in which free radicals were generated, causing lipid peroxidation of platelet membranes, thus simulating the disease process found in the brain.Results. 1. Al and Aβ 25 - 35 caused lipid peroxidation in the presence of the iron (II) ion (Fe2+, Al being more toxic than Aβ 25 - 35. 2. Aβ 25 - 35 attenuated the lipid peroxidation promoted by Al. 3. Hydrogen peroxide (H2O2 greatly exacerbated the toxicity of Al and Aβ 25 - 35. 4. Melatonin prevented lipid peroxidation by Al and Aβ 25 - 35 in the absence of H2O2, but only reduced the process when H2O2 was present.Conclusions. In the light of the results obtained from the present study, the following hypotheses are formulated. 1. In AD, excessive quantities of Al are taken up into the  brain, where the Al exacerbates iron-induced lipid peroxidatian in the Iysosomes. 2. In response, the normal synthetic pathway of amyloid protein is altered to produce Aβ fragments which attenuate the toxicity of Al. In the process of sequestering the Al and iron, immature plaques are formed in the brain. 3. Microglia are activated, in an attempt to destroy the plaques by secreting reactive oxygen species such as H2O2. At this point in the disease process, lipid peroxidation causes a catastrophic loss of brain cells. 4. Melatonin, together with other free radical scavengers in the brain, reduces the free-radical damage caused by Al and Aβ, except in the latter stages of the disease process. Since melatonin is produced by the pineal gland only in the dark, the excess of electric light in developed countries may help explain why AD is more prevalent in these countries than in rural Africa

    Adjustments made to recent catches and CPUE for West Coast Rock Lobster in Areas 3+4 and 5+6

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    During the 2017/18 fishing season, some catches made in Area 3+4 by trapboats were landed in Area 5+6 as hoopnet catches. This document reports the methodology used and the results obtained from an attempt to correct the catches reported for these super-areas to adjust for this malpractice

    Evaluation of the ASTERTM process in the presence of suspended solids

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    The ability to recycle and reuse process water is a major contributing factor toward increased sustainability in the mining industry. However, the presence of toxic compounds has prevented this in most bioleaching operations. The ASTERTM process has been used for the bioremediation of cyanide (CN) and thiocyanate (SCN−) containing effluents at demonstration and commercial scale, increasing the potential for recycling of the treated effluent. The process relies on a complex consortium of microorganisms and laboratory tests have shown that the biomass retention, in suspended flocs or attached biofilm, significantly improved SCN− degradation rates. The current research evaluated the process performance in the presence of suspended solids (up to 5.5% m/v) ahead of implementation at a site where complete tailings removal is not possible. Experiments were performed in four 1 l CSTRs (with three primary reactors in parallel at an 8 h residence time, feeding one secondary reactor at a 2.7 h residence time). Stable operation at the design specifications (5.5% solids, 100 mg/l SCN− feed, effluent SCN− 57 mg/l/h was achieved, despite no obvious floc formation. Microbial ecology studies (16S rRNA clone library) revealed reduced diversity relative to reactors operated without suspended solids

    Trends in genotypic HIV-1 antiretroviral resistance between 2006 and 2012 in South African patients receiving first- and second-line antiretroviral treatment regimens

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    The original publication is available at http://www.plosone.org/Publication of this article was funded by the Stellenbosch University Open Access Fund.BibliographyObjectives: South Africa’s national antiretroviral (ARV) treatment program expanded in 2010 to include the nucleoside reverse transcriptase (RT) inhibitors (NRTI) tenofovir (TDF) for adults and abacavir (ABC) for children. We investigated the associated changes in genotypic drug resistance patterns in patients with first-line ARV treatment failure since the introduction of these drugs, and protease inhibitor (PI) resistance patterns in patients who received ritonavir-boosted lopinavir (LPV/r)-containing therapy. Methods: We analysed ARV treatment histories and HIV-1 RT and protease mutations in plasma samples submitted to the Tygerberg Academic Hospital National Health Service Laboratory. Results: Between 2006 and 2012, 1,667 plasma samples from 1,416 ARV-treated patients, including 588 children and infants, were submitted for genotypic resistance testing. Compared with 720 recipients of a d4T or AZT-containing first-line regimen, the 153 recipients of a TDF-containing first-line regimen were more likely to have the RT mutations K65R (46% vs 4.0%; p<0.001), Y115F (10% vs. 0.6%; p<0.001), L74VI (8.5% vs. 1.8%; p<0.001), and K70EGQ (7.8% vs. 0.4%) and recipients of an ABC-containing first-line regimen were more likely to have K65R (17% vs 4.0%; p<0.001), Y115F (30% vs 0.6%; p<0.001), and L74VI (56% vs 1.8%; p<0.001). Among the 490 LPV/r recipients, 55 (11%) had ≥1 LPV-resistance mutations including 45 (9.6%) with intermediate or high-level LPV resistance. Low (20 patients) and intermediate (3 patients) darunavir (DRV) cross resistance was present in 23 (4.6%) patients. Conclusions: Among patients experiencing virological failure on a first-line regimen containing two NRTI plus one NNRTI, the use of TDF in adults and ABC in children was associated with an increase in four major non- thymidine analogue mutations. In a minority of patients, LPV/r-use was associated with intermediate or high-level LPV resistance with predominantly low-level DRV cross-resistance.Stellenbosch University Open Access FundPublishers' Versio

    Perceived readiness for hospital discharge : patients with spinal cord injury versus physiotherapists

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    BACKGROUND : Successful discharge from rehabilitation for patients with spinal cord injury (PWSCI) relies on a smooth transition home. Assessing readiness for hospital discharge (RHD) is important in reducing secondary health conditions and improving satisfaction and function. Perception of PWSCI on RHD may be different from their physiotherapists, leading to difficulties. OBJECTIVE : To compare the perceptions of PWSCI and physiotherapists with regard to RHD. METHOD : A comparative cross-sectional study included 50 PWSCI and their physiotherapists in Tshwane. They completed the Readiness for Hospital Discharge Scale (RHDS) and their responses to the subscales were compared. Data were analysed using descriptive and inferential statistics. Relationships between variables of interest and the general perception of RHD were determined using Pearson’s chi-square test. An independent samples t-test was used to analyse the difference in RHDS scores (including subscale scores) between PWSCI and physiotherapists. Results were significant if p < 0.05. RESULTS : The total score of the RHDS was not significantly different (t = 1.31, df = 98, p = 0.19). Patients had higher perceptions in coping ability and expected support subscales (t = 3.15, df = 85.97, p = 0.002 and t = 4.23, df = 98, p = 0.0001, respectively). Physiotherapists had higher perceptions in the knowledge subscale regarding what to do and not do at home (t = -2.05, df = 82.08, p = 0.044) and follow-up sessions (t = 2.625, df = 85.28, p = 0.010). CONCLUSION : There was no difference in perception of readiness to go home, although physiotherapists gave lower scores for emotional readiness and ability to handle demands at home and higher scores for knowledge. CLINICAL IMPLICATIONS : The use of the RHDS in the spinal cord rehabilitation units will better align the goals of rehabilitation and discharge planning to improve overall satisfaction with care and discharge outcomes. All members of a multidisciplinary team can achieve consensus and comparisons can be made on their patient’s perceived RHD.http://www.sajp.co.zaam2018Physiotherap

    Week 96 Extension Results of a Phase 3 Study Evaluating Long-Acting Cabotegravir with Rilpivirine for HIV-1 Treatment

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    BACKGROUND: ATLAS (NCT02951052), a phase 3, multicenter, open-label study, demonstrated that switching to injectable cabotegravir (CAB) with rilpivirine (RPV) long-acting dosed every 4 weeks was noninferior at week (W) 48 to continuing three-drug daily oral current antiretroviral therapy (CAR). Results from the W 96 analysis are presented. METHODS AND DESIGN: Participants completing W 52 of ATLAS were given the option to withdraw, transition to ATLAS-2M (NCT03299049), or enter an Extension Phase to continue long-acting therapy (Long-acting arm) or switch from CAR to long-acting therapy (Switch arm). Endpoints assessed at W 96 included proportion of participants with plasma HIV-1 RNA less than 50 copies/ml, incidence of confirmed virologic failure (CVF; two consecutive HIV-1 RNA ≥200 copies/ml), safety and tolerability, pharmacokinetics, and patient-reported outcomes. RESULTS: Most participants completing the Maintenance Phase transitioned to ATLAS-2M (88%, n = 502/572). Overall, 52 participants were included in the W 96 analysis of ATLAS; of these, 100% (n = 23/23) and 97% (n = 28/29) in the Long-acting and Switch arms had plasma HIV-1 RNA less than 50 copies/ml at W 96, respectively. One participant had plasma HIV-1 RNA 50 copies/ml or higher in the Switch arm (173 copies/ml). No participants met the CVF criterion during the Extension Phase. No new safety signals were identified. All Switch arm participants surveyed preferred long-acting therapy to their previous daily oral regimen (100%, n = 27/27). CONCLUSION: In this subgroup of ATLAS, 98% (n = 51/52) of participants at the Extension Phase W 96 analysis maintained virologic suppression with long-acting therapy. Safety, efficacy, and participant preference results support the therapeutic potential of long-acting CAB+RPV treatment for virologically suppressed people living with HIV-1

    Nucleoside Reverse Transcriptase Inhibitor Resistance Mutations Associated with First-Line Stavudine-Containing Antiretroviral Therapy: Programmatic Implications for Countries Phasing Out Stavudine

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    Background The World Health Organization Antiretroviral Treatment Guidelines recommend phasing-out stavudine because of its risk of long-term toxicity. There are two mutational pathways of stavudine resistance with different implications for zidovudine and tenofovir cross-resistance, the primary candidates for replacing stavudine. However, because resistance testing is rarely available in resource-limited settings, it is critical to identify the cross-resistance patterns associated with first-line stavudine failure. Methods We analyzed HIV-1 resistance mutations following first-line stavudine failure from 35 publications comprising 1,825 individuals. We also assessed the influence of concomitant nevirapine vs. efavirenz, therapy duration, and HIV-1 subtype on the proportions of mutations associated with zidovudine vs. tenofovir cross-resistance. Results Mutations with preferential zidovudine activity, K65R or K70E, occurred in 5.3% of individuals. Mutations with preferential tenofovir activity, ≥two thymidine analog mutations (TAMs) or Q151M, occurred in 22% of individuals. Nevirapine increased the risk of TAMs, K65R, and Q151M. Longer therapy increased the risk of TAMs and Q151M but not K65R. Subtype C and CRF01_AE increased the risk of K65R, but only CRF01_AE increased the risk of K65R without Q151M. Conclusions Regardless of concomitant nevirapine vs. efavirenz, therapy duration, or subtype, tenofovir was more likely than zidovudine to retain antiviral activity following first-line d4T therap
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