3,097 research outputs found

    Space tug propulsion system failure mode, effects and criticality analysis

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    For purposes of the study, the propulsion system was considered as consisting of the following: (1) main engine system, (2) auxiliary propulsion system, (3) pneumatic system, (4) hydrogen feed, fill, drain and vent system, (5) oxygen feed, fill, drain and vent system, and (6) helium reentry purge system. Each component was critically examined to identify possible failure modes and the subsequent effect on mission success. Each space tug mission consists of three phases: launch to separation from shuttle, separation to redocking, and redocking to landing. The analysis considered the results of failure of a component during each phase of the mission. After the failure modes of each component were tabulated, those components whose failure would result in possible or certain loss of mission or inability to return the Tug to ground were identified as critical components and a criticality number determined for each. The criticality number of a component denotes the number of mission failures in one million missions due to the loss of that component. A total of 68 components were identified as critical with criticality numbers ranging from 1 to 2990

    Spatial variation and temporal trends of testicular cancer in Great Britain

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    Increases in testicular cancer incidence have been reported in several countries over a long period. Geographical variability has also been reported in some studies. We have investigated temporal trends and spatial variation of testicular cancer at ages 20–49 in Britain. Temporal trends in testicular cancer incidence were examined, 1974 to 1991 and in mortality, 1981–1997. Spatial variation in incidence was analysed across electoral wards, 1975 to 1991. We used Poisson regression to examine for regional and socio-economic effects and Bayesian mapping techniques to analyse small-area spatial variability. Incidence increased from 6.5 to 11.1 per 100 000 in men at ages 20–34, and from 5.6 to 9.7 per 100 000 in men at ages 35–49, while mortality declined by 50% in both age groups. Risks of testicular cancer varied across regional cancer registries, ranging from 0.79 (95% CI: 0.73–0.84) to 1.32 (95% CI: 1.25–1.38), and was higher in the most affluent compared with the most deprived areas. Analyses within 2 regions (one predominantly urban, the other predominantly rural) did not indicate any localized geographical clustering. The increasing incidence contrasted with a decreasing mortality over time in Great Britain, similar to that found in other countries. The higher risk in more affluent areas is not consistent with findings on social class at the individual level. The absence of any marked geographical variability at small area scale argues against a geographically varying environmental factor operating strongly in the aetiology of testicular cancer. © 2001 Cancer Research Campaign http://www.bjcancer.co

    Assessing the Time Variability of Jupiter's Tropospheric Properties from 1996 to 2011

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    We acquired and analyzed mid-infrared images of Jupiter's disk at selected wavelengths from NASA's Infrared Telescope Facility (IRTF) from 1996 to 2011, including a period of large-scale changes of cloud color and albedo. We derived the 100-300 mbar temperature structure, together with tracers of vertical motion: the thickness of a 600- mbar cloud layer, the 300-mbar abundance of the condensable gas NH3, and the 400- mbar para- vs. ortho-H2 ratio. The biggest visual change was detected in the normally dark South Equatorial Belt (SEB) that 'faded' to a light color in 2010, during which both cloud thickness and NH3 abundance rose; both returned to their pre-fade levels in 2011, as the SEB regained its normal dark color. The cloud thickness in Jupiter's North Temperate Belt (NTB) increased in 2002, coincident with its visible brightening, and its NH3 abundance spiked in 2002-2003. Jupiter's Equatorial Zone (EZ), a region marked by more subtle but widespread color and albedo change, showed high cloud thickness variability between 2007 and 2009. In Jupiter's North Equatorial Belt (NEB), the cloud thickened in 2005, then slowly decreased to a minimum value in 2010-2011. No temperature variations were associated with any of these changes, but we discovered temperature oscillations of approx.2-4 K in all regions, with 4- or 8-year periods and phasing that was dissimilar in the different regions. There was also no detectable change in the para- vs. ortho-H2 ratio over time, leading to the possibility that it is driven from much deeper atmospheric levels and may be time-invariant. Our future work will continue to survey the variability of these properties through the Juno mission, which arrives at Jupiter in 2016, and to connect these observations with those made using raster-scanned images from 1980 to 1993 (Orton et al. 1996 Science 265, 625)

    The relationship between pre-construction decision-making and the quality of risk control: Testing the time-safety influence curve

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    Purpose - The purpose of this paper is to explore the relationship between the timing with which decisions are made about how to control work health and safety (WHS) risks in construction project (i.e. either pre- or post-construction) and the quality of risk control outcomes. Design/methodology/approach - Data were collected from 23 construction projects in Australia and the USA. Totally, 43 features of work were identified for analysis and decision making in relation to these features of work was mapped across the life of the projects. The quality of risk control outcomes was assessed using a classification system based on the "hierarchy of control". Within this hierarchy, technological forms of control are preferable to behavioural forms of controls. Findings - The results indicate that risk control outcomes were significantly better in the Australian compared with the US cases. The results also reveal a significant relationship between the quality of risk controls and the timing of risk control selection decisions. The greater the proportion of risk controls selected during the pre-construction stages of a project, the better the risk control outcomes. Research limitations/implications - The results provide preliminary evidence that technological risk controls are more likely to be implemented if WHS risks are considered and controls are selected in the planning and design stages of construction projects. Practical implications - The research highlights the need for WHS risk to be integrated into decision making early in the life of construction projects. Originality/value - Previous research has linked accidents to design. However, the retrospective nature of these studies has not permitted an analysis of the effectiveness of integrating WHS into pre-construction decision making. Prospective studies have been lacking. This research provides empirical evidence in support of the relationship between early consideration of WHS and risk control effectiveness

    Excavations and the afterlife of a professional football stadium, Peel Park, Accrington, Lancashire: towards an archaeology of football

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    Association football is now a multi-billion dollar global industry whose emergence spans the post-medieval to the modern world. With its professional roots in late 19th-century industrial Lancashire, stadiums built for the professionalization of football first appear in frequency in the North of England. While many historians of sport focus on consumerism and ‘topophilia’ (attachment to place) regarding these local football grounds, archaeological research that has been conducted on the spectator experience suggests status differentiation within them. Our excavations at Peel Park confirm this impression while also showing a significant afterlife to this stadium, particularly through children’s play

    Access to and experience of education for children and adolescents with cancer: a scoping review protocol

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    BACKGROUND: Cancer diagnosis in childhood or adolescence impacts significantly on school attendance, experience and educational outcomes. While there is longstanding recognition in clinical practice that these effects span the whole illness trajectory and continue beyond treatment completion, further clarity is required on the specific barriers and facilitators to education during cancer treatment and beyond, as well as on the experiences of children and adolescents across the full range of education settings (hospital, home, virtual, original school of enrolment), in order to determine which interventions are successful in improving access and experience from their perspective. The aim of this review is to identify what is known from the existing literature about access to and experience of education for children and adolescents with cancer during and post treatment. METHODS: We have planned a scoping literature review searching the following databases from inception onwards: MEDLINE (Ovid), Embase and Embase Classic, Web of Science Core Collection, Education Resources Index, Sociological Abstracts, APA PsycINFO, SCOPUS, CINAHL Plus, Emcare and The Cochrane Library. In addition, DARE, conference abstracts, key journals, and institutional websites will be searched. Arksey and O'Malley's six-step process will be followed, including a consultation exercise. Studies, reports and policies from any country providing care and treatment for children and adolescents with cancer published in English will be considered eligible for inclusion. Two reviewers will independently screen all citations, full-text articles and abstract data. A narrative summary of findings will be conducted. Data analysis will involve quantitative (e.g., frequencies) and qualitative (e.g., content and thematic analysis) methods. DISCUSSION: This is a timely examination given the increased incidence of childhood cancer, more intensive treatment regimens and improved survival rates for childhood cancer. The inclusion of a substantive consultation exercise with families and professionals will provide an important opportunity to examine the scoping review outputs. Findings will assist the childhood cancer community in developing a comprehensive evidence-based understanding of a significant associated bio-psychosocial impact of cancer diagnosis and treatment and will form the first step towards developing effective interventions and policies to mitigate identified detrimental effects. SYSTEMATIC REVIEW REGISTRATION: Open Science Framework (osf/io/yc4wt)

    Ultrasound erosions in the feet best predict progression to inflammatory arthritis in anti-CCP positive at-risk individuals without clinical synovitis

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    Objectives To investigate, in anti-cyclic citrullinated peptide antibody positive (CCP+) at-risk individuals without clinical synovitis, the prevalence and distribution of ultrasound (US) bone erosions (BE), their correlation with subclinical synovitis and their association with the development of inflammatory arthritis (IA). Methods Baseline US scans of 419 CCP+ at-risk individuals were analysed. BE were evaluated in the classical sites for rheumatoid arthritis damage: the second and fifth metacarpophalangeal (MCP2 and MCP5) joints, and the fifth metatarsophalangeal (MTP5) joints. US synovitis was defined as synovial hypertrophy (SH) ≥2 or SH ≥1+power Doppler signal ≥1. Subjects with ≥1 follow-up visit were included in the progression analysis (n=400). Results BE were found in ≥1 joint in 41/419 subjects (9.8%), and in 55/2514 joints (2.2%). The prevalence of BE was significantly higher in the MTP5 joints than in the MCP joints (p1 joint 10.6 (95% CI 1.9 to 60.4, p<0.01) and BE and synovitis in ≥1 MTP5 joint 5.1 (95% CI 1.4 to 18.9, p=0.02). In high titre CCP+ at-risk individuals, with positive rheumatoid factor and BE in ≥1 joint, the OR increased to 16.9 (95% CI 2.1–132.8, p<0.01). Conclusions In CCP+ at-risk individuals, BE in the feet appear to precede the onset of clinical synovitis. BE in >1 joint, and BE in combination with US synovitis in the MTP5 joints, are the most predictive for the development of clinical arthritis

    Ontologies, Mental Disorders and Prototypes

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    As it emerged from philosophical analyses and cognitive research, most concepts exhibit typicality effects, and resist to the efforts of defining them in terms of necessary and sufficient conditions. This holds also in the case of many medical concepts. This is a problem for the design of computer science ontologies, since knowledge representation formalisms commonly adopted in this field do not allow for the representation of concepts in terms of typical traits. However, the need of representing concepts in terms of typical traits concerns almost every domain of real world knowledge, including medical domains. In particular, in this article we take into account the domain of mental disorders, starting from the DSM-5 descriptions of some specific mental disorders. On this respect, we favor a hybrid approach to the representation of psychiatric concepts, in which ontology oriented formalisms are combined to a geometric representation of knowledge based on conceptual spaces
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