693 research outputs found

    Experimental clean combustor program, phase 1

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    A program of screening three low emission combustors for conventional takeoff and landing, by testing and analyzing thirty-two configurations is presented. Configurations were tested that met the emission goals at idle operating conditions for carbon monoxide and for unburned hydrocarbons (emission index values of 20 and 4, respectively). Configurations were also tested that met a smoke number goal of 15 at sea-level take-off conditions. None of the configurations met the goal for oxides of nitrogen emissions at sea-level take-off conditions. The best configurations demonstrated oxide of nitrogen emission levels that were approximately 61 percent lower than those produced by the JT9D-7 engine, but these levels were still approximately 24 percent above the goal of an emission index level of 10. Additional combustor performance characteristics, including lean blowout, exit temperature pattern factor and radial profile, pressure loss, altitude stability, and altitude relight characteristics were documented. The results indicate the need for significant improvement in the altitude stability and relight characteristics. In addition to the basic program for current aircraft engine combustors, seventeen combustor configurations were evaluated for advanced supersonic technology applications. The configurations were tested at cruise conditions, and a conceptual design was evolved

    Experimental clean combustor program, phase 2

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    The alternate fuels investigation objective was to experimentally determine the impacts, if any, on exhaust emissions, performance, and durability characteristics of the hybrid and vorbix low pollution combustor concepts when operated on test fuels which simulate composition and property changes which might result from future broadened aviation turbine fuel specifications or use of synthetically derived crude feedstocks. Results of the program indicate a significant increase in CO and small NOX increase in emissions at idle for both combustor concepts, and an increase in THC for the vorbix concept. Minimal impact was observed on gaseous emissions at high power. The vorbix concept exhibited significant increase in exhaust smoke with increasing fuel aromatic content. Altitude stability was not affected for the vorbix combustor, but was substantially reduced for the hybrid concept. Severe carbon deposition was observed in both combustors following limited endurance testing with No. 2 home heat fuel. Liner temperature levels were insensitive to variations in aromatic content over the range of conditions investigated

    Heterogeneous Spine Loss in Layer 5 Cortical Neurons after Spinal Cord Injury

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    A large thoracic spinal cord injury disconnects the hindlimb (HL) sensory-motor cortex from its target, the lumbar spinal cord. The fate of the synaptic structures of the axotomized cortical neurons is not well studied. We evaluated the density of spines on axotomized corticospinal neurons at 3, 7, and 21 days after the injury in adult mice expressing yellow fluorescence protein in a subset of layer 5 neurons. Spine density of the dendritic segment proximal to the soma (in layer 5) declined as early as 3 days after injury, far preceding the onset of somatic atrophy. In the distal segment (in layer 2/3), spine loss was slower and less severe than in the proximal segment. Axotomy of corticospinal axons in the brainstem (pyramidotomy) induced a comparable reduction of spine density, demonstrating that the loss is not restricted to the neurons axotomized in the thoracic spinal cord. Surprisingly, in both forms of injury, the spine density of putative non-axotomized layer 5 neurons was reduced as well. The spine loss may reflect fast rearrangements of cortical circuits after axotomy, for example, by a disconnection of HL cortical neurons from synaptic inputs that no longer provide useful informatio

    A New Swiss Federal Act on Gambling: From Missed Opportunities towards a Public Health Approach?

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    In January 2019, a new Swiss Federal Act on Gambling (Loi federal de jeux d'argent: LJAr) entered into force following a vote by the Swiss electorate. Intended to modernize and harmonize previous law and open the market for online casinos; the new regulations have highlighted the need for a comprehensive monitoring system. The present article outlines work undertaken by experts within the field to identify and elaborate the first steps towards developing such a monitoring system. This work includes the mapping of institutional actors and draft conceptualization of an impact model, including structural (i.e., prevention and intervention-based components), process (means), and outcomes (effect) indicators. Initial estimations of effective access to indicators and their perceived priority for data gathering are also described. Subsequent steps necessary for implementation of this public health approach for gambling are considered including grey areas for future action

    Los recursos humanos en enfermería desde la perspectiva de la fuerza de trabajo: análisis de la producción científica

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    Este estudio es una investigación sobre recursos humanos en enfermería, particularmente en la perspectiva de la fuerza de trabajo, realizado con los objetivos de identificar la producción científica nacional sobre recursos humanos en enfermería; analizar, particularmente, las publicaciones sobre fuerza de trabajo de enfermería; y elaborar una serie histórica sobre la composición y la distribución de esa fuerza de trabajo en el país. La investigación bibliográfica fue realizada en las bases de datos LILACS, PeriEnf, DEDALUS, BDENF, PAHO, MS, ADSAUDE, ENSP, FSP, TEXTOC, SIDORH y en los Catálogos del CEPEn, en el período de 1958 al 2001. Se identificaron 469 publicaciones, 345 (73,6%) con el descriptor recursos humanos de enfermería, 79 (16,8%) y 45 (9,6%) respectivamente con los unitérminos fuerza de trabajo de enfermería (FTE) y mercado de trabajo de enfermería. Se observa una concentración de la producción en la segunda mitad de los años 80 y toda la década del 90.Trata-se de pesquisa sobre recursos humanos em enfermagem, particularmente na perspectiva da força de trabalho, com os objetivos de identificar a produção científica nacional sobre recursos humanos em enfermagem; analisar, particularmente, as publicações sobre força de trabalho de enfermagem; e elaborar uma série histórica sobre a composição e a distribuição dessa força de trabalho no país. A pesquisa bibliográfica foi realizada nas bases de dados LILACS, PeriEnf, DEDALUS, BDENF, PAHO, MS, ADSAUDE, ENSP, FSP, TEXTOC, SIDORH e nos Catálogos do CEPEn, no período de 1958 a 2001. Identificaram-se 469 publicações, 345 (73,6%) com o descritor recursos humanos de enfermagem, 79 (16,8%) e 45 (9,6%) respectivamente com os unitermos força de trabalho de enfermagem (FTE) e mercado de trabalho de enfermagem. Observa-se uma concentração da produção na segunda metade dos anos 80 e toda a década de 90.The focus of this research is on human resources in nursing, particularly from the perspective of workforce. The objectives are to identify the national scientific production on human resources in nursing, analyze particularly those publications about work-force in nursing, and give a historical perspective on the composition of nursing workforce and the distribution of nursing workers throughout the country. In this bibliographic research LILACS, PeriEnf, DEDALUS, BDENF, PAHO, MS, ADSAUDE, ENSP, FSP, TEXTOC and SIDORH's databases were consulted, as well as CEPEn's catalogues, from 1958 to 2001. 469 publications were identified: 345 (73,6%) utilized human resources in nursing as a descriptor, while 79 (16,8%) and 45 (9,6%) utilized, respectively, the keywords nursing workforce (FTE) and nursing work market. There is a higher concentration of scientific production in the second half of the 80's and throughout the 90's

    Dominance of a clonal green sulfur bacterial population in a stratified lake

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    For many years, the chemocline of the meromictic Lake Cadagno, Switzerland, was dominated by purple sulfur bacteria. However, following a major community shift in recent years, green sulfur bacteria (GSB) have come to dominate. We investigated this community by performing microbial diversity surveys using FISH cell counting and population multilocus sequence typing [clone library sequence analysis of the small subunit (SSU) rRNA locus and two loci involved in photosynthesis in GSB: fmoA and csmCA]. All bacterial populations clearly stratified according to water column chemistry. The GSB population peaked in the chemocline (c. 8 × 106 GSB cells mL−1) and constituted about 50% of all cells in the anoxic zones of the water column. At least 99.5% of these GSB cells had SSU rRNA, fmoA, and csmCA sequences essentially identical to that of the previously isolated and genome-sequenced GSB Chlorobium clathratiforme strain BU-1 (DSM 5477). This ribotype was not detected in Lake Cadagno before the bloom of GSB. These observations suggest that the C. clathratiforme population that has stabilized in Lake Cadagno is clonal. We speculate that such a clonal bloom could be caused by environmental disturbance, mutational adaptation, or invasio

    Child feces disposal practices in rural Orissa: a cross sectional study.

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    BACKGROUND: An estimated 2.5 billion people worldwide lack access to improved sanitation facilities. While large-scale programs in some countries have increased latrine coverage, they sometimes fail to ensure optimal latrine use, including the safe disposal of child feces, a significant source of exposure to fecal pathogens. We undertook a cross-sectional study to explore fecal disposal practices among children in rural Orissa, India in villages where the Government of India's Total Sanitation Campaign had been implemented at least three years prior to the study. METHODS AND FINDINGS: We conducted surveys with heads of 136 households with 145 children under 5 years of age in 20 villages. We describe defecation and feces disposal practices and explore associations between safe disposal and risk factors. Respondents reported that children commonly defecated on the ground, either inside the household (57.5%) for pre-ambulatory children or around the compound (55.2%) for ambulatory children. Twenty percent of pre-ambulatory children used potties and nappies; the same percentage of ambulatory children defecated in a latrine. While 78.6% of study children came from 106 households with a latrine, less than a quarter (22.8%) reported using them for disposal of child feces. Most child feces were deposited with other household waste, both for pre-ambulatory (67.5%) and ambulatory (58.1%) children. After restricting the analysis to households owning a latrine, the use of a nappy or potty was associated with safe disposal of feces (OR 6.72, 95%CI 1.02-44.38) though due to small sample size the regression could not adjust for confounders. CONCLUSIONS: In the area surveyed, the Total Sanitation Campaign has not led to high levels of safe disposal of child feces. Further research is needed to identify the actual scope of this potential gap in programming, the health risk presented and interventions to minimize any adverse effect
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