186 research outputs found

    Molecular screening for Plasmodium falciparum resistance markers for artemisinins in Mbita, Kenya

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    Artemisinins-based combination therapies (ACTs) are being recommended against uncomplicated malaria in endemic areas of Africa. However, in these areas data on their long term usefulness is limited. It has been demonstrated that ACTs resistance may be due to single nucleotide polymorphisms (SNPs) in the chemotherapeutic target, the SERCA-type ATPase protein (PfATPase6). This study analyzed PfATPase6 mutations in asymptomatic infections from samples collected from Mbita, a malaria endemic region in Kenya. Mutations in A623E and S769N residues were screened with gene specific primers followed by sequencing. The study demonstrates that there is no mutation in Mbita, Kenya because neither A623E nor S769N PfATPase6 mutations were detected. Resurgence of infections in this area could be due to re-infections and not drug failure. The study recommends that other sites be assessed for PfATPase 6 mutations to verify the long-term usefulness of ACT and monitor any emergency of resistance.Keywords: ACT (Artemisinins-based Combination Therapy), Molecular, Mutations, PfATPase 6doi: 10.4314/ajcem.v12i3.

    Multiple Parton Interactions in Z+jets production at the LHC. A comparison of factorized and non--factorized double parton distribution functions

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    We examine the contribution of Multiple Parton Interactions to Z+n-jets production at the LHC, n=2,3,4, where the Z boson is assumed to decay leptonically. We compare the results obtained with the correlated GS09 double parton distribution function with those obtained with two instances of fully factorized single parton distribution functions: MSTW2008LO and CTEQ6LO. It appears quite feasible to measure the MPI contribution to Z+2/3/4 jets already in the first phase of the LHC with a total luminosity of one inverse femtobarn at 7 TeV. If as expected the trigger threshold for single photons is around 80 GeV, Z+2-jets production may well turn out to be more easily observable than the gamma+3-jets channel. The MPI cross section is dominated by relatively soft events with two jets balancing in transverse momentum.Comment: 15 pages, 3 plot

    Incorporating feasibility and collaboration into large-scale planning for regional recovery of coral reef fisheries

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    Broad-scale overharvesting of fish is one of the major drivers of marine biodiversity loss and poverty, particularly in countries with high dependence on coral reefs. Given the heterogeneity of fishing effort and management success, and the scarcity of management resources, it is necessary to identify broad-scale locations for promoting successful fisheries management and conservation. Here, we assessed how fisheries management and conservation priorities in the Western Indian Ocean would change if the objectives were to (1) minimize lost fishing opportunity, (2) minimize the time for fish biomass to recover, (3) avoid locations of low management feasibility based on historical management outcomes, and (4) incorporate international collaboration to optimize the rate for achieving goals. When prioritizing for rapid recovery of fish biomass rather than minimizing lost fishing opportunity, we found that the area of priority management zones changed by over 60% in some countries. When locations of low management feasibility were avoided, the recovery time of fish biomass across the region increased 4-fold. International collaborations prioritized management zones in remote, high biomass, and low fishing pressure reefs and reduced the recovery time of fish 5-fold compared to non-collaboration scenarios. Thus, many of these conservation objectives favored wealthy and sparsely populated over poorer and natural resource dependent countries. Consequently, this study shows how prioritization policies, incentives, decisions, and conflicts will produce highly variable outcomes and challenges for sustainability

    <i>Trypanosoma brucei rhodesiense</i> transmitted by a single tsetse fly bite in vervet monkeys as a model of human African trypanosomiasis

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    Sleeping sickness is caused by a species of trypanosome blood parasite that is transmitted by tsetse flies. To understand better how infection with this parasite leads to disease, we provide here the most detailed description yet of the course of infection and disease onset in vervet monkeys. One infected tsetse fly was allowed to feed on each host individual, and in all cases infections were successful. The characteristics of infection and disease were similar in all hosts, but the rate of progression varied considerably. Parasites were first detected in the blood 4-10 days after infection, showing that migration of parasites from the site of fly bite was very rapid. Anaemia was a key feature of disease, with a reduction in the numbers and average size of red blood cells and associated decline in numbers of platelets and white blood cells. One to six weeks after infection, parasites were observed in the cerebrospinal fluid (CSF), indicating that they had moved from the blood into the brain; this was associated with a white cell infiltration. This study shows that fly-transmitted infection in vervets accurately mimics human disease and provides a robust model to understand better how sleeping sickness develops

    Combination of electroweak and QCD corrections to single W production at the Fermilab Tevatron and the CERN LHC

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    Precision studies of the production of a high-transverse momentum lepton in association with missing energy at hadron colliders require that electroweak and QCD higher-order contributions are simultaneously taken into account in theoretical predictions and data analysis. Here we present a detailed phenomenological study of the impact of electroweak and strong contributions, as well as of their combination, to all the observables relevant for the various facets of the p\smartpap \to {\rm lepton} + X physics programme at hadron colliders, including luminosity monitoring and Parton Distribution Functions constraint, WW precision physics and search for new physics signals. We provide a theoretical recipe to carefully combine electroweak and strong corrections, that are mandatory in view of the challenging experimental accuracy already reached at the Fermilab Tevatron and aimed at the CERN LHC, and discuss the uncertainty inherent the combination. We conclude that the theoretical accuracy of our calculation can be conservatively estimated to be about 2% for standard event selections at the Tevatron and the LHC, and about 5% in the very high WW transverse mass/lepton transverse momentum tails. We also provide arguments for a more aggressive error estimate (about 1% and 3%, respectively) and conclude that in order to attain a one per cent accuracy: 1) exact mixed O(ααs){\cal O}(\alpha \alpha_s) corrections should be computed in addition to the already available NNLO QCD contributions and two-loop electroweak Sudakov logarithms; 2) QCD and electroweak corrections should be coherently included into a single event generator.Comment: One reference added. Final version to appear in JHE

    Survey of attitudes, materials and methods employed in endodontic treatment by general dental practitioners in North Jordan

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    BACKGROUND: General dental practitioners provide the majority of endodontic treatment in Jordan. The aim of this study was to gather information on the methods, materials and attitudes employed in root canal treatment by dentists in North Jordan, in order to evaluate and improve the quality of current practice. METHODS: A questionnaire was posted to all registered general dental practitioners working in private practice in Irbid Governate in North Jordan (n = 181). The questionnaire included information on methods, materials and techniques used in endodontic treatment. RESULTS: Reply rate was 72% (n = 131). The results demonstrated that only five dentists used rubber dam occasionally and not routinely. The majority used cotton rolls for isolation solely or in combination with a high volume saliva ejector (n = 116). The most widely used irrigants were sodium hypochlorite and hydrogen peroxide, which were used by 32.9% (n = 43) and 33.6% (n = 44) of the respondents, respectively. Forty eight percent of the respondents (n = 61) used the cold lateral condensation technique for canal obturation, 31.3% (n = 41) used single cone, 9.9% (n = 13) used vertical condensation and 12.2% (n = 16) used paste or cement only for the obturation. The majority used zinc oxide eugenol as a sealer (72.5%). All, but one, respondents used hand instruments for canal preparation and the technique of choice was step back (52.7%). More than 50% (n = 70) of the dentists took one radiograph for determining the working length, whilst 22.9% (n = 30) did not take any radiograph at all. Most practitioners performed treatment in three visits for teeth with two or more root canals, and in two visits for teeth with a single root canal. CONCLUSIONS: This study indicates that dentists practicing in North Jordan do not comply with international quality standards and do not use recently introduced techniques. Many clinicians never take a radiograph for determining the working length and never used rubber dam or intra-canal medicaments

    Diversification of refugia types needed to secure the future of coral reefs subject to climate change

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    Identifying locations of refugia from the thermal stresses of climate change for coral reefs and better managing them is one of the key recommendations for climate change adaptation. We review and summarize approximately 30 years of applied research focused on identifying climate refugia to prioritize the conservation actions for coral reefs under rapid climate change. We found that currently proposed climate refugia and the locations predicted to avoid future coral losses are highly reliant on excess heat metrics, such as degree heating weeks. However, many existing alternative environmental, ecological, and life-history variables could be used to identify other types of refugia that lead to the desired diversified portfolio for coral reef conservation. To improve conservation priorities for coral reefs, there is a need to evaluate and validate the predictions of climate refugia with long-term field data on coral abundance, diversity, and functioning. There is also the need to identify and safeguard locations displaying resistance toprolonged exposure to heat waves and the ability to recover quickly after thermal exposure. We recommend using more metrics to identify a portfolio of potential refugia sites for coral reefs that can avoid, resist, and recover from exposure to high ocean temperatures and the consequences of climate change, thereby shifting past efforts focused on avoidance to a diversified risk-spreading portfolio that can be used to improve strategic coral reef conservation in a rapidly warming climate

    Meeting fisheries, ecosystem function, and biodiversity goals in a human-dominated world

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    The worldwide decline of coral reefs necessitates targeting management solutions that can sustain reefs and the livelihoods of the people who depend on them. However, little is known about the context in which different reef management tools can help to achieve multiple social and ecological goals. Because of nonlinearities in the likelihood of achieving combined fisheries, ecological function, and biodiversity goals along a gradient of human pressure, relatively small changes in the context in which management is implemented could have substantial impacts on whether these goals are likely to be met. Critically, management can provide substantial conservation benefits to most reefs for fisheries and ecological function, but not biodiversity goals, given their degraded state and the levels of human pressure they face

    Human African Trypanosomiasis in South Sudan: How Can We Prevent a New Epidemic?

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    Human African trypanosomiasis (HAT) has been a major public health problem in South Sudan for the last century. Recurrent outbreaks with a repetitive pattern of responding-scaling down activities have been observed. Control measures for outbreak response were reduced when the prevalence decreased and/or socio-political crisis erupted, leading to a new increase in the number of cases. This paper aims to raise international awareness of the threat of another outbreak of sleeping sickness in South Sudan. It is a review of the available data, interventions over time, and current reports on the status of HAT in South Sudan. Since 2006, control interventions and treatments providing services for sleeping sickness have been reduced. Access to HAT diagnosis and treatment has been considerably diminished. The current status of control activities for HAT in South Sudan could lead to a new outbreak of the disease unless 1) the remaining competent personnel are used to train younger staff to resume surveillance and treatment in the centers where HAT activities have stopped, and 2) control of HAT continues to be given priority even when the number of cases has been substantially reduced. Failure to implement an effective and sustainable system for HAT control and surveillance will increase the risk of a new epidemic. That would cause considerable suffering for the affected population and would be an impediment to the socioeconomic development of South Sudan
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