1,555 research outputs found

    A Comprehensive Regression Tree to Estimate Body Weight from the Skeleton * ,†

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87075/1/j.1556-4029.2011.01819.x.pd

    Diagnostic Importance of 3D CT Images in Klippel-Feil Syndrome with Multiple Skeletal Anomalies: A Case Report

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    We present here the case of a 12-year-old boy who had Klippel-Feil syndrome with renal, cardiac and multiple skeletal anomalies, and we show the relevent three-dimensional computed tomography images. Our patient had a triple renal pelvis, mitral valve prolapsus, multiple cervical vertebrae fusions, cervical ribs, hypoplasia of the right thumb, spina bifida of L5, lumbalization at the right side of S1 and a sacral curved defect. In this study, we discuss the atypical clinical features and the diagnostic value of three-dimensional CT for evaluating the skeletal anomalies of the Klippel-Feil syndrome cases

    Red-Cockaded Woodpecker Status and Management: West Gulf Coastal Plain and Interior Highlands

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    Red-cockaded woodpecker populations declined precipitously following European settlement and expansion and cutting of the original pine forests across the southeastern United States. By 1990 most residual populations lacked demographic viability, existed in degraded habitat, and were isolated from other populations. The primary causes of this situation were harvest of the original pine forests of the southeastern United States, conversion of forested lands to other uses, short-rotation silvicultural practices, and alteration of the fire regime in the regenerated forests. As social and legal mandates changed, management of red-cockaded woodpeckers became a higher priority. Intensive management for red-cockaded woodpeckers is currently practiced on most public and a few private lands that still support populations. Recent population trends and the current status of red-cockaded woodpeckers in Oklahoma, Arkansas, Texas, and Louisiana reflect historical factors and the efficacy of recent management

    PTF11kx: A Type-Ia Supernova with a Symbiotic Nova Progenitor

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    There is a consensus that Type-Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumsteller are detected and the SN ejecta are seen to interact with circumstellar material (CSM) starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.Comment: 27 pages, 5 figures. In pres

    Thermal photons in QGP and non-ideal effects

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    We investigate the thermal photon production-rates using one dimensional boost-invariant second order relativistic hydrodynamics to find proper time evolution of the energy density and the temperature. The effect of bulk-viscosity and non-ideal equation of state are taken into account in a manner consistent with recent lattice QCD estimates. It is shown that the \textit{non-ideal} gas equation of state i.e ϔ−3 P ≠0\epsilon-3\,P\,\neq 0 behaviour of the expanding plasma, which is important near the phase-transition point, can significantly slow down the hydrodynamic expansion and thereby increase the photon production-rates. Inclusion of the bulk viscosity may also have similar effect on the hydrodynamic evolution. However the effect of bulk viscosity is shown to be significantly lower than the \textit{non-ideal} gas equation of state. We also analyze the interesting phenomenon of bulk viscosity induced cavitation making the hydrodynamical description invalid. We include the viscous corrections to the distribution functions while calculating the photon spectra. It is shown that ignoring the cavitation phenomenon can lead to erroneous estimation of the photon flux.Comment: 11 pages, 13 figures; accepted for publication in JHE

    Assessing the psychometric and ecometric properties of neighborhood scales using adolescent survey data from urban and rural Scotland

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    This work was supported by NHS Health Scotland and the University of St Andrews.Background:  Despite the well-established need for specific measurement instruments to examine the relationship between neighborhood conditions and adolescent well-being outcomes, few studies have developed scales to measure features of the neighborhoods in which adolescents reside. Moreover, measures of neighborhood features may be operationalised differently by adolescents living in different levels of urban/rurality. This has not been addressed in previous studies. The objectives of this study were to: 1) establish instruments to measure adolescent neighborhood features at both the individual and neighborhood level, 2) assess their psychometric and ecometric properties, 3) test for invariance by urban/rurality, and 4) generate neighborhood level scores for use in further analysis. Methods:  Data were from the Scottish 2010 Health Behaviour in School-aged Children Survey, which included an over-sample of rural adolescents. The survey responses of interest came from questions designed to capture different facets of the local area in which each respondent resided. Intermediate data zones were used as proxies for neighborhoods. Internal consistency was evaluated by Cronbach’s alpha. Invariance was examined using confirmatory factor analysis. Multilevel models were used to estimate ecometric properties and generate neighborhood scores. Results:  Two constructs labeled neighborhood social cohesion and neighborhood disorder were identified. Adjustment was made to the originally specified model to improve model fit and measures of invariance. At the individual level, reliability was .760 for social cohesion and .765 for disorder, and between .524 and .571 for both constructs at the neighborhood level. Individuals in rural areas experienced greater neighborhood social cohesion and lower levels of neighborhood disorder compared with those in urban areas. Conclusions:  The scales are appropriate for measuring neighborhood characteristics experienced by adolescents across urban and rural Scotland, and can be used in future studies of neighborhoods and health. However, trade-offs between neighborhood sample size and reliability must be considered.Publisher PDFPeer reviewe

    Non-Critical Liouville String Escapes Constraints on Generic Models of Quantum Gravity

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    It has recently been pointed out that generic models of quantum gravity must contend with severe phenomenological constraints imposed by gravitational Cerenkov radiation, neutrino oscillations and the cosmic microwave background radiation. We show how the non-critical Liouville-string model of quantum gravity we have proposed escapes these constraints. It gives energetic particles subluminal velocities, obviating the danger of gravitational Cerenkov radiation. The effect on neutrino propagation is naturally flavour-independent, obviating any impact on oscillation phenomenology. Deviations from the expected black-body spectrum and the effects of time delays and stochastic fluctuations in the propagation of cosmic microwave background photons are negligible, as are their effects on observable spectral lines from high-redshift astrophysical objects.Comment: 15 pages LaTeX, 2 eps figures include

    A case of projectile trauma from the medieval Poulton Chapel, Cheshire, the United Kingdom

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    Excavations at the medieval cemetery of Poulton Chapel, Cheshire, have uncovered over 900 articulated human skeletal remains, with numbers predicted to reach as high as 1500 as excavations continue. The demographics of this archaeological site is typical of a medieval rural assemblage. However, SK535 provides a glimpse into some of the traumatic aspects of medieval life. The excavation of SK535 revealed a middle‐aged adult male around 168 cm in stature. His position of burial was typical of Christian burials with an east‐west orientation, but the positioning of his arms identified that this was not a typical burial. His right arm was flexed at the elbow crossing the thorax, whereas the left arm was in the extended position. This is different from the other arm positions observed at Poulton Chapel. A metal object, identified here as a Type M7 bodkin arrowhead, was recovered from underneath the right arm, from within the thorax. This arrowhead was potentially armour piercing, and the type was commonly used during the 12th–13th century. Radiocarbon dates obtained for SK535 coincide with the time of the use of this arrowhead. Following the initial assessment, the only other instance of trauma identified in SK535 was a healed transverse fracture to the right distal ulna. Due to the location of Poulton Chapel in Cheshire, SK535 could have been wounded by an arrow carrying the M7 bodkin during English‐Welsh border skirmishes, which occurred frequently during this time period. The demographic profile of this individual indicates a possible professional fighter of the medieval period; however, no firm skeletal evidence of occupation could be provided. Nonetheless, this case study not only highlights the violence experienced during the medieval period but also indicates the ability for the survival of some traumas

    Visual ecology of aphids – a critical review on the role of colours in host finding

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    We review the rich literature on behavioural responses of aphids (Hemiptera: Aphididae) to stimuli of different colours. Only in one species there are adequate physiological data on spectral sensitivity to explain behaviour crisply in mechanistic terms. Because of the great interest in aphid responses to coloured targets from an evolutionary, ecological and applied perspective, there is a substantial need to expand these studies to more species of aphids, and to quantify spectral properties of stimuli rigorously. We show that aphid responses to colours, at least for some species, are likely based on a specific colour opponency mechanism, with positive input from the green domain of the spectrum and negative input from the blue and/or UV region. We further demonstrate that the usual yellow preference of aphids encountered in field experiments is not a true colour preference but involves additional brightness effects. We discuss the implications for agriculture and sensory ecology, with special respect to the recent debate on autumn leaf colouration. We illustrate that recent evolutionary theories concerning aphid–tree interactions imply far-reaching assumptions on aphid responses to colours that are not likely to hold. Finally we also discuss the implications for developing and optimising strategies of aphid control and monitoring
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