2,695 research outputs found

    Entomological characterization of malaria in northern Colombia through vector and parasite species identification, and analyses of spatial distribution and infection rates

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    Background: Malaria remains a worldwide public health concern and, in Colombia, despite the efforts to stop malaria transmission, the incidence of cases has increased over the last few years. In this context, it is necessary to evaluate vector diversity, infection rates, and spatial distribution, to better understand disease transmission dynamics. This information may contribute to the planning and development of vector control strategies. Results: A total of 778 Anopheles mosquitoes were collected in fifteen localities of Córdoba from August 2015 to October 2016. Six species were identified and overall, Anopheles albimanus was the most widespread and abundant species (83%). Other species of the Nyssorhynchus subgenus were collected, including Anopheles triannulatus (13%), Anopheles nuneztovari (1%), Anopheles argyritarsis (< 1%) and two species belonging to the Anopheles subgenus: Anopheles pseudopunctipennis (3%) and Anopheles neomaculipalpus (< 1%). Four species were found naturally infected with two Plasmodium species: Anopheles nuneztovari was detected naturally infected with Plasmodium falciparum and Anopheles pseudopunctipennis with Plasmodium vivax, whereas An. albimanus and An. triannulatus were found infected with both parasite species and confirmed by nested PCR. Conclusions: In general, the obtained results were contrasting with previous studies in terms of the most abundant and widespread collected species, and regarding infection rates, which were higher than those previously reported. A positive relationship between mosquito local abundance at the locality level and human infection at the municipality level was found. Mosquito local abundance and the number of houses with mosquitoes in each village are factors explaining malaria human cases in these villages. The obtained results suggest that other factors related to the apparent variation in malaria eco-epidemiology in northern Colombia, must be identified, to provide health authorities with better decision tools aiming to design control and prevention strategies

    Analysis of a marker for cancer of the thyroid with a limit of detection

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    Limit of detection (LoD) is a common problem in the analysis of data generated by instruments that cannot detect very small concentra- tions or other quantities, resulting in left-censored measurements. Methods intended for data that are not subject to this problem are often difficult to modify for censoring. We adapt the simulation- extrapolation method, devised originally for fitting models with measurement error, to dealing with LoD in conjunction with a mix- ture analysis. The application relates the levels of thyroglobulin in individuals with cancer of the thyroid before and after treatment with radioactive iodine I–131. We conclude that the fitted mixture components correspond to levels of effectiveness of the treatment

    Lenguajes de ontologías web aplicados al sector turístico

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    El presente artículo describe los resultados del proyecto de investigación titulado “Plataforma TIC para propiciar la organización y colaboración de los diferentes actores del sector turístico en el Caribe Colombiano” y desarrolla algunos conceptos sobre aplicaciones de Ontologías Web al sector turismo. Una ontología defne los términos a utilizar para describir y representar un área de conocimiento. Las ontologías son utilizadas por personas, bases de datos y aplicaciones que necesitan compartir un dominio de información común e incluyen defniciones de conceptos básicos del dominio, y las relaciones entre ellos. El articulo inicia con el análisis del concepto de ontologías, los componentes que lo conforman y algunos lenguajes de ontologías web frecuentemente utilizados y explica cómo se pueden aplicar las ontologías al sector turístico. El artículo fnaliza explicando cómo se construyó un buscador de atractivos turísticos basado en ontologías.Abstract: This article describes the results of the research project entitled “ICT platform to promote the organization and collaboration of diferent actors in the tourism sector in the Colombian Caribbean” and develops some concepts about Web Ontology applications for tourism. An ontology defnes the terms to use to describe and represent an area of knowledge. Ontologies are used by people, databases and applications that need to share a common information domain and include defnitions of domain concepts and relations between them. The article begins with an analysis of the concept of ontologies, its components and some web ontology languages commonly used and explains how ontologies can be applied to the tourism sector. The article concludes by explaining how was built a seeker engine for sites based on ontologies

    Evaluation of the curvature ductility ratio of a circular cross-section of concrete reinforced with GFRP bars

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    The present study deals with the use of fiberglass reinforced polymer bars (GFRP) as a replacement for the common steel of a reinforced concrete circular pile, in order to avoid the corrosion of durability of reinforcing bars and thus improve them. The comparative analysis was carried out between a pile reinforced with GFRP and another with steel, where the ductility was evaluated by obtaining moment-curvature diagram. As a result, said idealized moment-curvature diagrams and ductility indices are presented, concluding the ductility of the section reinforced with GFRP in 20% more than that of steel

    Topiramate Treatment Is Neuroprotective and Reduces Oligodendrocyte Loss after Cervical Spinal Cord Injury

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    Excess glutamate release and associated neurotoxicity contributes to cell death after spinal cord injury (SCI). Indeed, delayed administration of glutamate receptor antagonists after SCI in rodents improves tissue sparing and functional recovery. Despite their therapeutic potential, most glutamate receptor antagonists have detrimental side effects and have largely failed clinical trials. Topiramate is an AMPA-specific, glutamate receptor antagonists that is FDA-approved to treat CNS disorders. In the current study we tested whether topiramate treatment is neuroprotective after cervical contusion injury in rats. We report that topiramate, delivered 15-minutes after SCI, increases tissue sparing and preserves oligodendrocytes and neurons when compared to vehicle treatment. In addition, topiramate is more effective than the AMPA-receptor antagonist, NBQX. To the best of our knowledge, this is the first report documenting a neuroprotective effect of topiramate treatment after spinal cord injury

    The significance of the episodic nature of atmospheric deposition to Low Nutrient Low Chlorophyll regions

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    Guieu, C. ... et. al.-- 20 pages, 7 figures, 2 tables, supporting information http://onlinelibrary.wiley.com/doi/10.1002/2014GB004852/suppinfoIn the vast Low Nutrient Low-Chlorophyll (LNLC) Ocean, the vertical nutrient supply from the subsurface to the sunlit surface waters is low, and atmospheric contribution of nutrients may be one order of magnitude greater over short timescales. The short turnover time of atmospheric Fe and N supply (<1 month for nitrate) further supports deposition being an important source of nutrients in LNLC regions. Yet, the extent to which atmospheric inputs are impacting biological activity and modifying the carbon balance in oligotrophic environments has not been constrained. Here, we quantify and compare the biogeochemical impacts of atmospheric deposition in LNLC regions using both a compilation of experimental data and model outputs. A metadata-analysis of recently conducted field and laboratory bioassay experiments reveals complex responses, and the overall impact is not a simple “fertilization effect of increasing phytoplankton biomass” as observed in HNLC regions. Although phytoplankton growth may be enhanced, increases in bacterial activity and respiration result in weakening of biological carbon sequestration. The application of models using climatological or time-averaged non-synoptic deposition rates produced responses that were generally much lower than observed in the bioassay experiments. We demonstrate that experimental data and model outputs show better agreement on short timescale (days to weeks) when strong synoptic pulse of aerosols deposition, similar in magnitude to those observed in the field and introduced in bioassay experiments, is superimposed over the mean atmospheric deposition fields. These results suggest that atmospheric impacts in LNLC regions have been underestimated by models, at least at daily to weekly timescales, as they typically overlook large synoptic variations in atmospheric deposition and associated nutrient and particle inputs. Inclusion of the large synoptic variability of atmospheric input, and improved representation and parameterization of key processes that respond to atmospheric deposition, is required to better constrain impacts in ocean biogeochemical models. This is critical for understanding and prediction of current and future functioning of LNLC regions and their contribution to the global carbon cycleThis article was initiated in Istanbul, Turkey during a 2 day workshop financed by the European CoOperation in Science and Technology (COST) Action 735 “Tools for assessing global air-sea fluxes of climate and air pollution relevant gases”. It is a contribution to the The International Surface Ocean - Lower Atmosphere Study (SOLAS) projectPeer reviewe

    Evidence for induction of humoral and cytotoxic immune responses against devil facial tumor disease cells in Tasmanian devils (Sarcophilus harrisii) immunized with killed cell preparations

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    Available online 20 February 2015Tasmanian devils (Sarcophilus harrisii) risk extinction from a contagious cancer, devil facial tumour disease (DFTD) in which the infectious agent is the tumor cell itself. Because devils are unable to produce an immune response against the tumor cells no devil has survived 'infection'. To promote an immune response we immunized healthy devils with killed DFTD tumor cells in the presence of adjuvants. Immune responses, including cytotoxicity and antibody production, were detected in five of the six devils. The incorporation of adjuvants that act via toll like receptors may provide additional signals to break 'immunological ignorance'. One of these devils was protected against a challenge with viable DFTD cells. This was a short-term protection as re-challenge one year later resulted in tumor growth. These results suggest that Tasmanian devils can generate immune responses against DFTD cells. With further optimization of immune stimulation it should be possible to protect Tasmanian devils against DFTD with an injectable vaccine.A. Kreiss, G.K. Brown, C. Tovar, A.B. Lyons, G.M. Wood

    Convergence analysis of hybrid cellular automata for topology optimization

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    The hybrid cellular automaton (HCA) algorithm was inspired by the structural adaptation of bones to their ever changing mechanical environment. This methodology has been shown to be an effective topology synthesis tool. In previous work, it has been observed that the convergence of the HCA methodology is affected by parameters of the algorithm. As a result, questions have been raised regarding the conditions by which HCA converges to an optimal design. The objective of this investigation is to examine the conditions that guarantee convergence to a Karush-Kuhn-Tucker (KKT) point. In this paper, it is shown that the HCA algorithm is a fixed point iterative scheme and the previously reported KKT optimality conditions are corrected. To demonstrate the convergence properties of the HCA algorithm, a simple cantilevered beam example is utilized. Plots of the spectral radius for projections of the design space are used to show regions of guaranteed convergence
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