1,236 research outputs found

    High prevalence of Trichomonas gallinae in wild columbids across western and southern Europe

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    Avian trichomonosis is known as a widespread disease in columbids and passerines, and recent findings have highlighted the pathogenic character of some lineages found in wild birds. Trichomonosis can affect wild bird populations including endangered species, as has been shown for Mauritian pink pigeons Nesoenas mayeri in Mauritius and suggested for European turtle doves Streptopelia turtur in the UK. However, the disease trichomonosis is caused only by pathogenic lineages of the parasite Trichomonas gallinae. Therefore, understanding the prevalence and distribution of both potentially pathogenic and non-pathogenic T. gallinae lineages in turtle doves and other columbids across Europe is relevant to estimate the potential impact of the disease on a continental scale

    Effect of stress relieving heat treatment on surface topography and dimensional accuracy of incrementally formed grade 1 titanium sheet parts

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    The forming of parts with an optimized surface roughness and high dimensional accuracy is important in many applications of incremental sheet forming (ISF). To realize this, the effect of stress relieving heat treatment of grade-1 Ti parts performed before and after forming on the surface finish and dimensional accuracy was studied. It was found that heat treatment at a temperature of 540 °C for 2 h improves the surface finish of formed parts resulting in a surface with little or no visible tool marks. Additionally, it improves the dimensional accuracy of parts after unclamping from the rig used for forming, in particular, that of parts with shallow wall angles (typically <25°). It was also noted that post-forming heat treatment improves the surface finish of parts. The surface topography of formed parts was studied using interferometry to yield areal surface roughness parameters and subsequently using secondary electron imaging. Back-scatter electron microscopy imaging results coupled with energy-dispersive X-ray (EDX) analysis showed that heat treatment prior to forming leads to tool wear as indicated by the presence of Fe in samples. Furthermore, post-forming heat treatment prevents curling up of formed parts due to compressive stresses if the formed part is trimmed

    A synthesis of bacterial and archaeal phenotypic trait data.

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    A synthesis of phenotypic and quantitative genomic traits is provided for bacteria and archaea, in the form of a scripted, reproducible workflow that standardizes and merges 26 sources. The resulting unified dataset covers 14 phenotypic traits, 5 quantitative genomic traits, and 4 environmental characteristics for approximately 170,000 strain-level and 15,000 species-aggregated records. It spans all habitats including soils, marine and fresh waters and sediments, host-associated and thermal. Trait data can find use in clarifying major dimensions of ecological strategy variation across species. They can also be used in conjunction with species and abundance sampling to characterize trait mixtures in communities and responses of traits along environmental gradients

    General Rules for Optimal Codon Choice

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    Different synonymous codons are favored by natural selection for translation efficiency and accuracy in different organisms. The rules governing the identities of favored codons in different organisms remain obscure. In fact, it is not known whether such rules exist or whether favored codons are chosen randomly in evolution in a process akin to a series of frozen accidents. Here, we study this question by identifying for the first time the favored codons in 675 bacteria, 52 archea, and 10 fungi. We use a number of tests to show that the identified codons are indeed likely to be favored and find that across all studied organisms the identity of favored codons tracks the GC content of the genomes. Once the effect of the genomic GC content on selectively favored codon choice is taken into account, additional universal amino acid specific rules governing the identity of favored codons become apparent. Our results provide for the first time a clear set of rules governing the evolution of selectively favored codon usage. Based on these results, we describe a putative scenario for how evolutionary shifts in the identity of selectively favored codons can occur without even temporary weakening of natural selection for codon bias

    Predictive Models for the Diagnostic of Human Visceral Leishmaniasis in Brazil

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    Visceral leishmaniasis (VL) is a neglected tropical disease endemic to 65 countries, including Brazil, where the disease frequently occurs in remote locations and treatment is often performed on the basis of clinical suspicion. Predictive models based on scoring systems could be a helpful tool for the clinical management of VL. Based on clinical signs and symptoms, and five different serological tests of 213 patients with parasitologically confirmed (cases) and 119 with clinical suspicion of VL but with another confirmed etiology (non-cases), twelve prediction models using logistic regression and classification and regression trees (CART) for VL diagnosis were developed. The model composed of the clinical-laboratory variables and the rk39 rapid test showed the best performance in both logistic regression and CART (Sensitivity of 90.1% and specificity ranging from 97.2–97.4%). The scoring system is simple and based on the clinical-laboratory findings that are easily available in most clinical settings. The results suggest that those models might be useful in locations where access to available diagnostic methods is difficult, contributing to more efficient and more rational allocation of healthcare resources

    Bond Strength of Gold Alloys Laser Welded to Cobalt-Chromium Alloy

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    The objective of this study was to investigate the joint properties between cast gold alloys and Co-Cr alloy laser-welded by Nd:YAG laser. Cast plates were fabricated from three types of gold alloys (Type IV, Type II and low-gold) and a Co-Cr alloy. Each gold alloy was laser-welded to Co-Cr using a dental laser-welding machine. Homogeneously-welded and non-welded control specimens were also prepared. Tensile testing was conducted and data were statistically analyzed using ANOVA. The homogeneously-welded groups showed inferior fracture load compared to corresponding control groups, except for Co-Cr. In the specimens welded heterogeneously to Co-Cr, Type IV was the greatest, followed by low-gold and Type II. There was no statistical difference (P<0.05) in fracture load between Type II control and that welded to Co-Cr. Higher elongations were obtained for Type II in all conditions, whereas the lowest elongation occurred for low-gold welded to Co-Cr. This study indicated that, of the three gold alloys tested, the Type IV gold alloy was the most suitable alloy for laser-welding to Co-Cr

    Work and health conditions of sugar cane workers in Brazil

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    This is an exploratory research, with a quantitative approach, developed with the objective of analyzing the work and of life situations that can offer risks to the workers' health involved in the manual and automated cut of the sugar cane. The sample was composed by 39 sugar cane cutters and 16 operators of harvesters. The data collection occurred during the months of July and August of 2006, by the technique of direct observation of work situations and workers' homes and through interviews semi-structured. The interviews were recorded and later transcribed. Data were analyzed according to Social Ecological Theory. It was observed that the workers deal with multiple health risk situations, predominantly to the risks of occurrence of respiratory, musculoskeletal and psychological problems and work-related accidents due to the work activities. The interaction of individual, social and environmental factors can determine the workers' tendency to falling ill.Se trata de una investigación exploratoria con abordaje cuantitativo de los datos, realizada con la meta de analizar las situaciones de trabajo y de vida que pueden generar riesgos sanitarios a los trabajadores involucrados en el corte manual y mecanizado de la caña de azúcar. La muestra se compuso de 39 cortadores de caña y 16 operadores de cose-cha-do-ras. La recolección de datos tuvo lugar en los meses de julio y agosto de 2006, utilizándose la técnica de observación directa de las situaciones de trabajo y residencia de los trabajadores y a través de entrevistas semiestructuradas, las cuales fueron grabadas y posteriormente transcriptas. Los datos fueron analizados a partir de la Teoría Social Ecológica. Se constató que los trabajadores están expuestos a innumerables situaciones de riesgo sanitario, en particular a los riesgos de sufrir problemas respiratorios, osteo-mus-culares y psicológicos, así como accidentes de trabajo derivados de su actividad laboral, y que su posibilidad de enfermar se determina por la interacción de factores individuales, ambientales y sociales.Trata-se de uma pesquisa exploratória, com abordagem quantitativa dos dados, realizada no intuito de analisar as situações de trabalho e de vida que podem oferecer riscos à saúde de trabalhadores envolvidos no corte manual e mecanizado da cana-de-açúcar. A amostra foi composta por 39 cortadores de cana e 16 operadores de colhedeiras. A coleta de dados ocorreu nos meses de julho e agosto de 2006, utilizando-se a técnica de observação direta das situações de trabalho e moradia dos trabalhadores, e por meio de entrevistas semi-estruturadas, que foram gravadas e posteriormente transcritas. Os dados foram analisados a partir da Teoria Social Ecológica. Foi constatado que os trabalhadores estão expostos a inúmeras situações de risco à saúde, predominantemente a riscos de ocorrência de problemas respiratórios, osteomusculares e psicológicos. Além disso, estão sujeitos a acidentes de trabalho em decorrência de sua atividade laboral. Constatou-se também que o adoecimento é determinado pela interação de fatores individuais, ambientais e sociais
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