24,393 research outputs found

    People with learning disabilities and mental health problems: the impact of ethnicity

    Get PDF
    There is increasing awareness of the needs of people with learning disabilities from different ethnic communities. This paper focuses on the impact of ethnicity on the presentation of mental health problems. The main aim of the paper is to inform those planning and delivering mental health services for people with learning disabilities of the current evidence, in order to enable their practice to improve health outcomes for people from minority ethnic communitie

    Non-thermal X-ray Emission: An Alternative to Cluster Cooling Flows?

    Get PDF
    We report the results of experiments aimed at reducing the major problem with cooling flow models of rich cluster X-ray sources: the fact that most of the cooled gas or its products have not been found. Here we show that much of the X-ray emission usually attributed to cooling flows can, in fact, be modeled by a power-law component which is indicative of a source(s) other than thermal bremsstrahlung from the intracluster medium. We find that adequate simultaneous fits to ROSAT PSPCB and ASCA GIS/SIS spectra of the central regions of ten clusters are obtained for two-component models that include a thermal plasma component that is attributable to hot intracluster gas and a power-law component that is likely generated by compact sources and/or extended non-thermal emission. For five of the clusters that purportedly have massive cooling flows, the best-fit models have power-law components that contribute ∼\sim 30 % of the total flux (0.14 - 10.0 keV) within the central 3 arcminutes. Because cooling flow mass deposition rates are inferred from X-ray fluxes, our finding opens the possibility of significantly reducing cooling rates.Comment: 11 pages, 3 figures, emulateapj style. Accepted for publication in Ap

    The validity of capillary blood sampling in the determination of human growth hormone concentration during exercise in men

    Get PDF
    This is an open access article - Copyright © 2004 BMJ Publishing Group LtdBACKGROUND: Studies measuring human growth hormone (hGH) in blood during exercise have mainly used venous sampling. The invasive nature of this procedure makes evaluation of hGH impossible in various exercise environments. OBJECTIVE: To determine whether capillary sampling could offer an alternative sampling method. METHODS: Capillary and venous blood samples were collected for determination of hGH at the end of each exercise stage during an incremental exercise test in 16 male club level competitive cyclists (mean (SD) age 30.8 (8.0) years, body mass 72.2 (7.1) kg, body fat 12.9 (3.5)%, peak oxygen consumption 4.18 (0.46) l⋅min−1). Linear regression, from a plot of venous v capillary blood hGH concentration, showed a correlation coefficient of r = 0.986 (p<0.001). When geometric means and log transformations were used, a coefficient of variation of 14.2% was demonstrated between venous and capillary flow for hGH concentration. The mean ratio limits of agreement were 0.62 (1.72)—that is, 95% of the ratios were contained between 0.36 and 1.07, with a mean of 0.62. CONCLUSIONS: Capillary blood sampling is an acceptable alternative to venous sampling for determining hGH concentration during rest and exercise. Sample sites should not be used interchangeably: one site should be chosen and its use standardised

    Estimation of mean sea surfaces in the north Atlantic, the Pacific and the Indian Ocean using GEOS-3 altimeter data

    Get PDF
    The mean surfaces of several regions of the world's oceans were estimated using GEOS-3 altimeter data. The northwest Atlantic, the northeast Pacific off the coast of California, the Indian Ocean, the southwest Pacific, and the Phillipine Sea are included. These surfaces have been oriented with respect to a common earth center-of-mass system by constraining the separate solutions to conform to precisely determined laser reference control orbits. The same reference orbits were used for all regions assuring continuity of the separate solutions. Radial accuracies of the control orbits were in the order of one meter. The altimeter measured sea surface height crossover differences were minimized by the adjustment of tilt and bias parameters for each pass with the exception of laser reference control passes. The tilt and bias adjustments removed long wavelength errors which were primarily due to orbit error. Ocean tides were evaluated. The resolution of the estimated sea surfaces varied from 0.25 degrees off the east coast of the United States to about 2 degrees in part of the Indian Ocean near Australia. The rms crossover discrepancy after adjustment varied from 30 cm to 70 cm depending upon geographic location. Comparisons of the altimeter derived mean sea surface in the North Atlantic with the 5 feet x 5 feet GEM-8 detailed gravimetric geoid indicated a relative consistency of better than a meter

    The composition of HB stars : RR Lyrae variables

    Get PDF
    We used moderately high-resolution, high S/N spectra to study the chemical composition of 10 field ab-type RR Lyrae stars. A new temperature scale was determined from literature Infrared Flux Method measures of subdwarfs and the Kurucz (1992) model atmospheres, and used to calibrate colors for both dwarfs and RR Lyraes. The applicability of Kurucz (1992) model atmospheres in the analysis of RR Lyraes at minimum light was analyzed: we found that they are able to reproduce colors, excitation and ionization equilibria as well as the wings of Halpha. We derived abundances for 21 species. The metal abundances of the program stars span the range -2.50<[Fe/H]<+0.17$. Lines of most elements are found to form in LTE conditions. Fe lines satisfy very well the excitation and ionization equilibria. RR Lyraes share the typical abundance pattern of other stars of similar [Fe/H]: alpha-elements are overabundant by about 0.4dex and Mn is underabundant by about 0.6dex in stars with [Fe/H]<-1. Significant departures from LTE are found only for a few species. We used our new [Fe/H] abundances, as well as values from Butler and coworkers (corrected to our system), and from high resolution spectroscopy of globular clusters giants, to obtain a new calibration of the DeltaS index: [Fe/H]= -0.194(\pm 0.011)DeltaS -0.08(\pm 0.18) and to update the metallicity calibration of the Ca II K line index: [Fe/H]= 0.65(\pm 0.17)W'(K) -3.49(\pm 0.39). Finally, our new metallicity scale was used to revise the [Fe/H] dependence of the absolute magnitude of RR Lyrae stars, Mv: Mv = 0.20(\pm 0.03)[Fe/H] + 1.06(\pm 0.04).Comment: 59 pages, Latex using aaspp.sty, ps-files of text, tables (21) and figures (23) available from ftp://boas3.bo.astro.it/pub/gisella To appear in October 1995 Astronomical Journa

    Clustering of equine grass sickness cases in the United Kingdom: a study considering the effect of position-dependent reporting on the space-time K-function

    Get PDF
    Equine grass sickness (EGS) is a largely fatal, pasture-associated dysautonomia. Although the aetiology of this disease is unknown, there is increasing evidence that Clostridium botulinum type C plays an important role in this condition. The disease is widespread in the United Kingdom, with the highest incidence believed to occur in Scotland. EGS also shows strong seasonal variation (most cases are reported between April and July). Data from histologically confirmed cases of EGS from England and Wales in 1999 and 2000 were collected from UK veterinary diagnostic centres. The data did not represent a complete census of cases, and the proportion of all cases reported to the centres would have varied in space and, independently, in time. We consider the variable reporting of this condition and the appropriateness of the space–time K-function when exploring the spatial-temporal properties of a ‘thinned’ point process. We conclude that such position-dependent under-reporting of EGS does not invalidate the Monte Carlo test for space–time interaction, and find strong evidence for space–time clustering of EGS cases (P<0.001). This may be attributed to contagious or other spatially and temporally localized processes such as local climate and/or pasture management practices

    Models of the ICM with Heating and Cooling: Explaining the Global and Structural X-ray Properties of Clusters

    Full text link
    (Abridged) Theoretical models that include only gravitationally-driven processes fail to match the observed mean X-ray properties of clusters. As a result, there has recently been increased interest in models in which either radiative cooling or entropy injection play a central role in mediating the properties of the intracluster medium. Both sets of models give reasonable fits to the mean properties of clusters, but cooling only models result in fractions of cold baryons in excess of observationally established limits and the simplest entropy injection models do not treat the "cooling core" structure present in many clusters and cannot account for entropy profiles revealed by recent X-ray observations. We consider models that marry radiative cooling with entropy injection, and confront model predictions for the global and structural properties of massive clusters with the latest X-ray data. The models successfully and simultaneously reproduce the observed L-T and L-M relations, yield detailed entropy, surface brightness, and temperature profiles in excellent agreement with observations, and predict a cooled gas fraction that is consistent with observational constraints. The model also provides a possible explanation for the significant intrinsic scatter present in the L-T and L-M relations and provides a natural way of distinguishing between clusters classically identified as "cooling flow" clusters and dynamically relaxed "non-cooling flow" clusters. The former correspond to systems that had only mild levels (< 300 keV cm^2) of entropy injection, while the latter are identified as systems that had much higher entropy injection. This is borne out by the entropy profiles derived from Chandra and XMM-Newton.Comment: 20 pages, 15 figures, accepted for publication in the Astrophysical Journa

    The scatter and evolution of the global hot gas properties of simulated galaxy cluster populations

    Get PDF
    We use the cosmo-OWLS suite of cosmological hydrodynamical simulations to investigate the scatter and evolution of the global hot gas properties of large simulated populations of galaxy groups and clusters. Our aim is to compare the predictions of different physical models and to explore the extent to which commonly-adopted assumptions in observational analyses (e.g. self-similar evolution) are violated. We examine the relations between (true) halo mass and the X-ray temperature, X-ray luminosity, gas mass, Sunyaev-Zel'dovich (SZ) flux, the X-ray analogue of the SZ flux (YXY_X) and the hydrostatic mass. For the most realistic models, which include AGN feedback, the slopes of the various mass-observable relations deviate substantially from the self-similar ones, particularly at late times and for low-mass clusters. The amplitude of the mass-temperature relation shows negative evolution with respect to the self-similar prediction (i.e. slower than the prediction) for all models, driven by an increase in non-thermal pressure support at higher redshifts. The AGN models predict strong positive evolution of the gas mass fractions at low halo masses. The SZ flux and YXY_X show positive evolution with respect to self-similarity at low mass but negative evolution at high mass. The scatter about the relations is well approximated by log-normal distributions, with widths that depend mildly on halo mass. The scatter decreases significantly with increasing redshift. The exception is the hydrostatic mass-halo mass relation, for which the scatter increases with redshift. Finally, we discuss the relative merits of various hot gas-based mass proxies.Comment: 31 pages (21 before appendices), 19 figures, 12 tables, accepted by MNRAS after minor revisio

    Blue Horizontal Branch Stars in M92

    Get PDF
    We have analyzed high dispersion and high precision spectra of 5 blue horizontal branch stars in the globular cluster M92 to establish that the projected rotational velocity for these stars ranges from 15 to 40 \kms. This is larger than that expected based on the rotation of their main sequence progenitors, the spin down of rotation with age, and the conservation of angular momentum. Possible explanations include a rapidly rotating stellar core. An abundance analysis of these spectra of these blue HB stars in M92 yields the same results as have been obtained from the giants in this cluster. There is a hint of a trend of higher abundance as the projected surface rotational velocity increases, which could be chance and requires confirmation.Comment: 14 pages with 2 figures, LateX, to be published in the Astronomical Journa
    • …
    corecore