79 research outputs found

    Space and surface power for the space exploration initiative: Results from project outreach

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    The analysis and evaluations of the Space and Surface Power panel, one of eight panels created by RAND to screen and analyze submissions to the Space Exploration Initiative (SEI) Outreach Program, is documented. In addition to managing and evaluating the responses, or submissions, to this public outreach program, RAND conducted its own analysis and evaluation relevent to SEI mission concepts, systems, and technologies. The Power panel screened and analyzed submissions for which a substantial portion of the concepts involved power generation sources, transmission, distribution, thermal management, and handling of power (including conditioning, conversion, packaging, and enhancements in system components). A background discussion of the areas the Power panel covered and the issues the reviewers considered pertinent to the analysis of power submissions are presented. An overview of each of the highest-ranked submissions and then a discussion of these submissions is presented. The results of the analysis is presented

    Analysis and evaluation of groundwater protection alternatives during waste extraction operations (acid tars) in a lagoon in Arganda del Rey (Madrid)

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    [Resumen:] La Comunidad de Madrid está llevando a cabo la restauración integral de una antigua gravera contaminada con residuos peligrosos, mayoritariamente sulfonatos de petróleo (alquitranes ácidos), procedentes del tratamiento de aceites industriales usados. Parte de dichos vertidos, realizados en las décadas de los años 1970 y 1980, se depositaron en una laguna originada por la explotación de áridos por debajo del nivel piezométrico del acuífero, conformando una balsa con 50000 m3 de residuos peligrosos. La diversa ubicación, naturaleza y estado de los residuos requiere diferentes soluciones para su extracción y tratamiento, por lo que el proyecto de restauración consta de varias fases. Los residuos depositados producen un efecto de confinamiento en el acuífero, dado que la cota del fondo de los residuos es inferior al nivel piezométrico. Con estos condicionantes es crítico establecer un procedimiento de protección de las aguas subterráneas a la hora de acometer la próxima fase, consistente en la extracción de los residuos situados por debajo del nivel piezométrico. En este artículo se describe el proceso que se ha llevado a cabo para seleccionar la mejor alternativa desde el punto de vista hidrogeológico, considerando todos los datos disponibles obtenidos en las fases previas del proyecto. Una vez planteadas y caracterizadas todas las alternativas posibles se ha seleccionado de forma argumentada y razonada como mejor alternativa la realización de una barrera impermeabilizante perimetral a la balsa y empotrada en una capa de arcillas de 2 m de espesor situada en el subsuelo de la balsa.[Abstract:] The Community of Madrid is carrying out the integral restoration of an old gravel pit contaminated with hazardous waste, mostly petroleum sulphonates (acid tars), from the treatment of used industrial oil. Part of these discharges, from the 1970s and 1980s, were deposited in a lagoon generated by the exploitation of aggregates below the piezometric level of the aquifer, forming a raft with 50,000 m3 of hazardous waste. The different locations, nature and conditions of the waste require different solutions for its extraction and treatment, so the restoration project consists of several phases. The deposited waste produces an effect of confinement in the aquifer, since the bottom level of the waste is lower than the piezometric level. With these conditions, it is critical to establish a procedure for the protection of the groundwater when executing the next phase, consisting of the extraction of waste located below the piezometric level. This article describes the process that has been carried out to select the best alternative from a hydrogeological point of view, considering all the available data obtained in the previous phases of the project. Once all the possible alternatives had been considered and characterized in a reasoned way, we chose the construction of a perimeter barrier around the raft embedded in a clay layer of 2 m thick located in the base of the raft as the best option

    Variability in the performance of preventive services and in the degree of control of identified health problems: A primary care study protocol

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    Background: Preventive activities carried out in primary care have important variability that makes necessary to know which factors have an impact in order to establish future strategies for improvement. The present study has three objectives: 1) To describe the variability in the implementation of 7 preventive services (screening for smoking status, alcohol abuse, hypertension, hypercholesterolemia, obesity, influenza and tetanus immunization) and to determine their related factors; 2) To describe the degree of control of 5 identified health problems (smoking, alcohol abuse, hypertension, hypercholesterolemia and obesity); 3) To calculate intraclass correlation coefficients. Design: Multi-centered cross-sectional study of a randomised sample of primary health care teams from 3 regions of Spain designed to analyse variability and related factors of 7 selected preventive services in years 2006 and 2007. At the end of 2008, we will perform a cross-sectional study of a cohort of patients attended in 2006 or 2007 to asses the degree of control of 5 identified health problems. All subjects older than16 years assigned to a randomised sample of 22 computerized primary health care teams and attended during the study period are included in each region providing a sample with more than 850.000 subjects. The main outcome measures will be implementation of 7 preventive services and control of 5 identified health problems. Furthermore, there will be 3 levels of data collection: 1) Patient level (age, gender, morbidity, preventive services, attendance); 2) Health-care professional level (professional characteristics, years working at the team, workload); 3) Team level (characteristics, electronic clinical record system). Data will be transferred from electronic clinical records to a central database with prior encryption and dissociation of subject, professional and team identity. Global and regional analysis will be performed including standard analysis for primary health care teams and health-care professional level. Linear and logistic regression multilevel analysis adjusted for individual and cluster variables will also be performed. Variability in the number of preventive services implemented will be calculated with Poisson multilevel models. Team and health-care professional will be considered random effects. Intraclass correlation coefficients, standard error and variance components for the different outcome measures will be calculated

    Semi-viviparous embryo development and dehydrin expression in the mangrove Rhizophora mucronata Lam.

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    Rhizophora mucronata Lam. is a tropical mangrove with semi-viviparous (cotyledon body protrusion before shedding), non-quiescent and non-desiccating (recalcitrant) seeds. As recalcitrance has been thought to relate to the absence of desiccation-related proteins such as dehydrins, we for the first time systematically described and classified embryogenesis in R. mucronata and assessed the presence of dehydrin-like proteins. Embryogenesis largely follows the classic pattern till stage eight, the torpedo stage, with the formation of a cotyledonary body. Ovule and embryo express radical adaptations to semi-vivipary in the saline environment: (1) A large, highly vacuolated and persistent endosperm without noticeable food reserves that envelopes the developing embryo. (2) Absence of vascular tissue connections between embryo and maternal tissue, but, instead, transfer layers in between endosperm and integument and endosperm and embryo. Dehydrin-like proteins (55–65 kDa) were detected by the Western analysis, in the ovules till stage 10 when the integuments are dehisced. An additional 50 kDa band was detected at stages 6–8. Together these results suggest a continuous flow of water with nutrients from the integument via the endosperm to the embryo, circumventing the vascular route and probably suppressing the initially induced dehydrin expression

    Study protocol of psychometric properties of the Spanish translation of a competence test in evidence based practice: The Fresno test

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    <p>Abstract</p> <p>Background</p> <p>There are few high-quality instruments for evaluating the effectiveness of Evidence-Based Practice (EBP) curricula with objective outcomes measures. The Fresno test is an instrument that evaluates most of EBP steps with a high reliability and validity in the English original version. The present study has the aims to translate the Fresno questionnaire into Spanish and its subsequent validation to ensure the equivalence of the Spanish version against the English original.</p> <p>Methods and design</p> <p>The questionnaire will be translated with the back translation technique and tested in Primary Care Teaching Units in Catalonia (PCTU). Participants will be: (a) tutors of Family Medicine residents (expert group); (b) Family Medicine residents in their second year of the Family Medicine training program (novice group), and (c) Family Medicine physicians (intermediate group). The questionnaire will be administered before and after an educational intervention. The educational intervention will be an interactive four half-day sessions designed to develop the knowledge and skills required to EBP. Responsiveness statistics used in the analysis will be the effect size, the standardised response mean and Guyatt's method. For internal consistency reliability, two measures will be used: corrected item-total correlations and Cronbach's alpha. Inter-rater reliability will be tested using Kappa coefficient for qualitative items and intra-class correlation coefficient for quantitative items and the overall score. Construct validity, item difficulty, item discrimination and feasibility will be determined.</p> <p>Discussion</p> <p>The validation of the Fresno questionnaire into different languages will enable the expansion of the questionnaire, as well as allowing comparison between countries and the evaluation of different teaching models.</p

    Mechanics rules cell biology

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    Cells in the musculoskeletal system are subjected to various mechanical forces in vivo. Years of research have shown that these mechanical forces, including tension and compression, greatly influence various cellular functions such as gene expression, cell proliferation and differentiation, and secretion of matrix proteins. Cells also use mechanotransduction mechanisms to convert mechanical signals into a cascade of cellular and molecular events. This mini-review provides an overview of cell mechanobiology to highlight the notion that mechanics, mainly in the form of mechanical forces, dictates cell behaviors in terms of both cellular mechanobiological responses and mechanotransduction

    Targeted Curing of All Lysogenic Bacteriophage from Streptococcus pyogenes Using a Novel Counter-selection Technique

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    We thank the members of the Laboratory of Microbial Pathogenesis and Immunology, especially Annette Nelkenbaum and Ben Winer for their technical assistance. We also thank Estee Colleen Cervantes and Sutapa Banerjee from Hunter College for their technical contribution to this project. We are grateful to Joseph Ferretti for S. pyogenes strain SF370.Streptococcus pyogenes is a human commensal and a bacterial pathogen responsible for a wide variety of human diseases differing in symptoms, severity, and tissue tropism. The completed genome sequences of >37 strains of S. pyogenes, representing diverse disease-causing serotypes, have been published. The greatest genetic variation among these strains is attributed to numerous integrated prophage and prophage-like elements, encoding several virulence factors. A comparison of isogenic strains, differing in prophage content, would reveal the effects of these elements on streptococcal pathogenesis. However, curing strains of prophage is often difficult and sometimes unattainable. We have applied a novel counter-selection approach to identify rare S. pyogenes mutants spontaneously cured of select prophage. To accomplish this, we first inserted a two-gene cassette containing a gene for kanamycin resistance (KanR) and the rpsL wild-type gene, responsible for dominant streptomycin sensitivity (SmS), into a targeted prophage on the chromosome of a streptomycin resistant (SmR) mutant of S. pyogenes strain SF370. We then applied antibiotic counter-selection for the re-establishment of the KanS/SmR phenotype to select for isolates cured of targeted prophage. This methodology allowed for the precise selection of spontaneous phage loss and restoration of the natural phage attB attachment sites for all four prophage-like elements in this S. pyogenes chromosome. Overall, 15 mutants were constructed that encompassed every permutation of phage knockout as well as a mutant strain, named CEM1ΔΦ, completely cured of all bacteriophage elements (a ~10% loss of the genome); the only reported S. pyogenes strain free of prophage-like elements. We compared CEM1ΔΦ to the WT strain by analyzing differences in secreted DNase activity, as well as lytic and lysogenic potential. These mutant strains should allow for the direct examination of bacteriophage relationships within S. pyogenes and further elucidate how the presence of prophage may affect overall streptococcal survival, pathogenicity, and evolution.Yeshttp://www.plosone.org/static/editorial#pee
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