563 research outputs found

    How comparable are different measures of self-rated health? Evidence from five European countries

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    Self-rated health (SRH) is a common health measurement in international research. Yet different versions of this item are often applied. This study compares the US (United States) version (from excellent to poor) and the EU (European) version (from very good to very bad) of SRH, and examines differences in their associations with demographic and objective health variables. Data were drawn from the Survey of Health, Ageing and Retirement in Europe (SHARE), comprising information from 11,622 respondents aged 50 years and over in five countries. Respondents were presented with both the EU and US versions. Information was collected on basic demographics and health variables including chronic diseases, symptoms, functional limitations and depression. Firstly, the distribution of each version of the SRH item was assessed, and both relative and literal concordance was examined. Subsequently, multivariate regression analysis was used to assess differences in the associations of both items with demographic and health indicators. The US version has a more symmetric distribution and smaller variance than the EU version. Although the EU version discriminates better at the negative end, the US version shows better discrimination at the negative end of the scale. 69% of respondents provided literally concordant answers, while only about one third provided relatively concordant answers. Overall, however, less than 10% of respondents were discordant in either sense. Furthermore, the two versions were strongly correlated (polychoric correlatio

    CONDUCTIVE PATHWAYS CONSTRUCTION USING GENETIC ALGORITHM AND CONSTRUCTAL DESIGN

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    In this work, Constructal Design and Genetic Algorithms are used to construct high conductivity paths connected to a heat sink and inserted in a square plate of low conductivity material with internal heat generation. The objective is propose a methodology that leads to minimize the maximum solid domain temperature. Total volume of the plate, amount of high thermal conductivity material and thermal ratio between high and low conductivities are fixed. The high conductive pathway forms found in this work greately resembles to the tree-forms found in nature, on which temperature is efficiently minimized by the application of the Genetic Algorithm and the Constructal Theory combined

    Influence of ocean acidification on the organic complexation of iron and copper in Northwest European shelf seas; a combined observational and model study

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    The pH of aqueous solutions is known to impact the chemical speciation of trace metals. In this study we conducted titrations of coastal seawaters with iron and copper at pH 7.91, 7.37 and 6.99 (expressed on the total pH scale). Changes in the concentration of iron and copper that complexed with the added ligands 1-nitroso-2-napthol and salicylaldoxime respectively were determined by adsorptive cathodic stripping voltammetry - competitive ligand equilibrium (AdCSV-CLE). Interpretation of the results, assuming complexation by a low concentration of discrete ligands, showed that conditional stability constants for iron complexes increased relative to inorganic iron complexation as pH decreased by approximately 1 log unit per pH unit, whilst those for copper did not change. No trend was observed for concentrations of iron and copper complexing ligands over the pH range examined. We also interpreted our titration data by describing chemical binding and polyelectrolytic effects using non-ideal competitive adsorption in Donnan-like gels (NICA-Donnan model) in a proof of concept study. The NICA-Donnan approach allows for the development of a set of model parameters that are independent of ionic strength and pH, and thus calculation of metal speciation can be undertaken at ambient sample pH or the pH of a future, more acidic ocean. There is currently a lack of basic NICA-Donnan parameters applicable to marine dissolved organic matter (DOM) so we assumed that the measured marine dissolved organic carbon could be characterized as terrestrial fulvic acids. Generic NICA-Donnan parameters were applied within the framework of the software program visual MINTEQ and the metal –added ligand concentrations [MeAL] calculated for the AdCSV-CLE conditions. For copper, calculated [MeAL] using the NICA-Donnan model for DOM were consistent with measured [MeAL], but for iron an inert fraction with kinetically inhibited dissolution was required in addition to the NICA-Donnan model in order to approximate the trends observed in measured [MeAL]. We calculated iron and copper speciation in Northwest European shelf water samples at ambient alkalinity and projected increased pCO2 concentrations as a demonstration of the potential of the approach

    Resultados de la Revision Ambiental Inicial en la institucion universiaria Politecnico Grancolombiano

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    Environmental diagnosis of the Politecnico Grancolombiano University, following the Norms of ISO 14001 it makes part, together with the Flora Evaluation and Floors of the Politecnico Grancolombiano University and the Design of a Plan of Environmental Improvement, of a first stage of analysis of the environmental situation of the institution from the perspectives of the impacts generated by her and of the execution of the effective environmental legislation. As a result of these works, following the same line, it is developed the project Structural Analysis at the moment and I Design of a System of Environmental Administration, guided by the norms of ISO 14001. In this study a comparative valuation of those will be made the Systems of Environmental Administration (SGA), in different universities and companies, to settle down, finally, a Plan of adjusted Institutional Environmental Handling to the nature of the organization like institution of academic formation

    Genetic basis of Campylobacter colonisation in the broiler chicken and its impact on intestinal health following natural field exposure

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    Campylobacter is the leading bacterial cause of foodborne diarrheal illness in humans and source attribution studies unequivocally identify handling or consumption of poultry meat as a key risk factor. Campylobacter colonizes the avian intestines in high numbers and rapidly spreads within flocks. A need therefore exists to devise strategies to reduce Campylobacter populations in poultry flocks. There has been a great deal of research aiming to understand the epidemiology and transmission characteristics of Campylobacter in poultry as a means to reduce carriage rates in poultry and reduce infection in humans. One potential strategy for control is the genetic selection of poultry for increased resistance to colonization by Campylobacter. The potential for genetic control of colonization has been demonstrated in inbred populations following experimental challenge with Campylobacter where quantitative trait loci associated with resistance have been identified. Currently in the literature there is no information of the genetic basis of Campylobacter colonization in commercial broiler lines and it is unknown whether these QTL are found in commercial broiler lines. The aim of this study was to estimate genetic parameters associated with Campylobacter load and genetic correlations with gut health and production traits following natural exposure of broiler chickens to Campylobacter. The results from the analysis show a low but significant heritability estimate (0.095 ± 0.037) for Campylobacter load which indicates a limited genetic basis and that non-genetic factors have a greater influence on the level of Campylobacter found in the broiler chicken. Furthermore, through examination of macroscopic intestinal health and absorptive capacity, our study indicated that Campylobacter has no detrimental effects on intestinal health and bird growth following natural exposure in the broiler line under study. These data indicate that whilst there is a genetic component to Campylobacter colonization worthy of further investigation, there is a large proportion of phenotypic variance under the influence of non-genetic effects. As such the control of Campylobacter will require understanding and manipulation of non-genetic host and environmental factors

    Single-molecule super-resolution imaging of chromosomes and in situ haplotype visualization using Oligopaint FISH probes

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    Fluorescence in situ hybridization (FISH) is a powerful single-cell technique for studying nuclear structure and organization. Here we report two advances in FISH-based imaging. We first describe the in situ visualization of single-copy regions of the genome using two single-molecule super-resolution methodologies. We then introduce a robust and reliable system that harnesses single-nucleotide polymorphisms (SNPs) to visually distinguish the maternal and paternal homologous chromosomes in mammalian and insect systems. Both of these new technologies are enabled by renewable, bioinformatically designed, oligonucleotide-based Oligopaint probes, which we augment with a strategy that uses secondary oligonucleotides (oligos) to produce and enhance fluorescent signals. These advances should substantially expand the capability to query parent-of-origin-specific chromosome positioning and gene expression on a cell-by-cell basis
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