6,361 research outputs found

    Pulmonary giant cells and their significance for the diagnosis of asphyxiation

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    This study was performed to prove whether the detection of polynuclear giant cells in lungs is useful for the diagnosis of asphyxiation due to throttling or strangulation. Therefore, lung specimens of 54 individuals with different natural and unnatural causes of death were investigated. In most lungs examined numerous alveolar macrophages with 1-2 nuclei were found. Polynuclear giant cells, which were arbitrarily defined as alveolar macrophages containing 3 or more nuclei, were observed in all groups investigated except in the cases of hypoxia due to covering the head with plastic bags. Apparent differences between the other groups in particular an increased number in cases of throttling or strangulation, could not be observed. Immunohistochemical investigations confirmed the hypothesis that the observed polynuclear giant cells were derived from alveolar macrophages. The immunohistochemical analysis of the proliferation marker antigen Ki 67 revealed no positive reaction in the nuclei of polynuclear giant cells indicating that these cells had not developed shortly before death by endomitosis as an adaptative change following reduction in oxygen supply. The results provide evidence that the detection of pulmonary polynuclear giant cells cannot be used as a practical indicator for death by asphyxiation due to throttling or strangulation

    Composite vertices that lead to soft form factors

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    The momentum-space cut-off parameter Λ\Lambda of hadronic vertex functions is studied in this paper. We use a composite model where we can measure the contributions of intermediate particle propagations to Λ\Lambda. We show that in many cases a composite vertex function has a much smaller cut-off than its constituent vertices, particularly when light constituents such as pions are present in the intermediate state. This suggests that composite meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda considerably less than 1 GeV. We discuss the origin of this softening of form factors as well as the implications of our findings on the modeling of nuclear reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request

    Effects of Hybrid Cycle and Handcycle Exercise on Cardiovascular Disease Risk Factors in People with Spinal Cord Injury:A Randomized Controlled Trial

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    Objective: To examine the effects of a 16-week exercise programme, using either a hybrid cycle or a handcycle, on cardiovascular disease risk factors in people with spinal cord injury.Participants: Nineteen individuals with spinal cord injury &gt;= 8 years.Design: Multicentre randomized controlled trial. Both the hybrid cycle group (n = 9) and the handcycle group (n = 10) trained twice a week for 16 weeks on the specific cycle. Outcome measures obtained pre and post the programme were: metabolic syndrome components (waist circumference, systolic and diastolic blood pressure, high-density lipoprotein cholesterol, triglycerides and insulin resistance), inflammatory status (C-reactive protein (CRP), interleukin (1)-6 and -10), and visceral adiposity (trunk and android fat).Results: For all outcome measures, there were no significant differences over time between the 2 training groups. Overall significant reductions were found for waist circumference (p = 0.001), diastolic blood pressure (p = 0.03), insulin resistance (p = 0.006), CRP (p = 0.05), IL-6 (p = 0.04), IL-6/IL-10 ratio (p = 0.03), and trunk (p = 0.04) and android (p = 0.02) fat percentage. No significant main effects for time were observed for systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, IL-10, and trunk and android fat mass.Conclusion: The 16-week exercise programme, using either a hybrid cycle or a handcycle, found similar beneficial effects on metabolic syndrome components, inflammatory status and visceral adiposity, indicating that there were no additional benefits of functional electrical stimulation-induced leg exercise over handcycle exercise alone.</p

    Natural Gas Compressibility Factor Measurement and Evaluation for High Pressure High Temperature Gas Reservoirs

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    The Natural gas compressibility factor is an important reservoir fluid property used in reservoir engineering computations either directly or indirectly in material balance calculations, well test analysis, gas reserve estimates, gas flow in lines and in numerical reservoir simulations. Existing gas compressibility factor correlations were derived using measured data at low to moderate pressures(less than 8, 000 psia) and temperatures (less than 212oF), and an extrapolation to High Pressure High temperature (HPHT) is doubtful. The need to understand and predict gas compressibility factor at HPHT has become increasingly important as exploration and production has moved to ever deeper formations where HPHT conditions are to be encountered. This paper presents laboratory measurement of gas compressibility factors at HPHT natural gas systems and the evaluation of some selected gas compressibility factors correlations. Samples of gas mixtures were collected from the high pressure gas reservoirs from the Niger Delta region of Nigeria. Vinci PVT Cell was used to measure the gas compressibility factors for a pressures ranging from 6,000 to 14,000 psia and temperatures at 270oF and 370oF. The new laboratory data was compared to some of the gas compressibility factor correlations/ models used in the petroleum industry. Results showed that majority of the correlations studied overestimated the gas compressibility factor at HPHT. Mean relative and absolute error analysis were done based on the temperature difference; it was found that the total mean relative and absolute errors for the 370o F cases are higher than those for 270oF. Among all the correlations assessed, Hall and Yarborough equation performed better than other existing correlations with a mean absolute error of 3.545 and relative error of -2.668 at 270oF. At 370oF, Beggs and Brills correlation predicted better than other correlations studied with a mean relative error of -4.77 and absolute error of 7.18

    Effect of long-term physical activity and acute exercise on markers of systemic inflammation in persons with chronic spinal cord injury: a systematic review

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    Objective: To evaluate the effect of long-term physical activity (PA) and acute exercise on markers of systemic inflammation in persons with chronic spinal cord injury (SCI)

    Fake supersymmetry versus Hamilton-Jacobi

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    We explain when the first-order Hamilton-Jacobi equations for black holes (and domain walls) in (gauged) supergravity, reduce to the usual first-order equations derived from a fake superpotential. This turns out to be equivalent to the vanishing of a newly found constant of motion and we illustrate this with various examples. We show that fake supersymmetry is a necessary condition for having physically sensible extremal black hole solutions. We furthermore observe that small black holes become scaling solutions near the horizon. When combined with fake supersymmetry, this leads to a precise extension of the attractor mechanism to small black holes: The attractor solution is such that the scalars move on specific curves, determined by the black hole charges, that are purely geodesic, although there is a non-zero potential.Comment: 20 pages, v2: Typos corrected, references adde

    The Next Generation Virgo Cluster Survey. VI. The Kinematics of Ultra-compact Dwarfs and Globular Clusters in M87

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    The origin of ultra-compact dwarfs (UCDs)--objects larger and more massive than typical globular clusters (GCs), but more compact than typical dwarf galaxies--has been hotly debated in the 15 years since their discovery. Even whether UCDs should be considered galactic in origin, or simply the most extreme GCs, is not yet settled. We present the dynamical properties of 97 spectroscopically confirmed UCDs (rh >~10 pc) and 911 GCs associated with central cD galaxy of the Virgo cluster, M87. Our UCDs, of which 89% have M_star > ~2X10^6 M_sun and 92% are as blue as the classic blue GCs, nearly triple the sample of previous confirmed Virgo UCDs, providing by far the best opportunity for studying the global dynamics of a UCD system. We found that (1) UCDs have a surface number density profile that is shallower than that of the blue GCs in the inner ~ 70 kpc and as steep as that of the red GCs at larger radii; (2) UCDs exhibit a significantly stronger rotation than the GCs, and the blue GCs seem to have a velocity field that is more consistent with that of the surrounding dwarf ellipticals than with that of UCDs; (3) UCDs have a radially increasing orbital anisotropy profile, and are tangentially-biased at radii < ~ 40 kpc and radially-biased further out. In contrast, the blue GCs become more tangentially-biased at larger radii beyond ~ 40 kpc; (4) GCs with M_star > 2X10^6 M_sun have rotational properties indistinguishable from the less massive ones, suggesting that it is the size, instead of mass, that differentiates UCDs from GCs as kinematically distinct populations. We conclude that most UCDs in M87 are not consistent with being merely the most luminous and extended examples of otherwise normal GCs. The radially-biased orbital structure of UCDs at large radii is in general agreement with the "tidally threshed dwarf galaxy" scenario.Comment: 27 pages, 21 figures. To appear in The Astrophysical Journa

    Testing the Meson Cloud Model in Inclusive Meson Production

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    We have applied the Meson Cloud Model to calculate inclusive momentum spectra of pions and kaons produced in high energy proton-proton and proton-nucleus collisions. For the first time these data are used to constrain the cloud cut-off parameters. We show that it is possible to obtain a reasonable description of data, especially the large xFx_F (xF0.2x_F \geq 0.2) part of the spectrum and at the same time describe (partially) the E866 data on dˉuˉ\bar d - \bar u and dˉ/uˉ\bar d / \bar u. We also discuss the relative strength of the πN\pi N and πΔ\pi \Delta vertices. We find out that the corresponding cut-off parameters should be both soft and should not differ by more than 200 MeV from each other. An additional source (other than the meson cloud) of sea antiquark asymmetry, seems to be necessary to completely explain the data. A first extension of the MCM to proton nucleus collisions is discussed.Comment: 14 pages, Latex, 6 ps figures. Submitted to Phys. Rev.

    The Next Generation Virgo Cluster Survey. X. Properties of Ultra-Compact Dwarfs in the M87, M49 and M60 Regions

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    We use imaging from the Next Generation Virgo cluster Survey (NGVS) to present a comparative study of ultra-compact dwarf (UCD) galaxies associated with three prominent Virgo sub-clusters: those centered on the massive, red-sequence galaxies M87, M49 and M60. We show how UCDs can be selected with high completeness using a combination of half-light radius and location in color-color diagrams (uiKsu^*iK_s or ugzu^*gz). Although the central galaxies in each of these sub-clusters have nearly identical luminosities and stellar masses, we find large differences in the sizes of their UCD populations, with M87 containing ~3.5 and 7.8 times more UCDs than M49 and M60, respectively. The relative abundance of UCDs in the three regions scales in proportion to sub-cluster mass, as traced by X-ray gas mass, total gravitating mass, number of globular clusters, and number of nearby galaxies. We find that the UCDs are predominantly blue in color, with ~85% of the UCDs having colors similar to blue GCs and stellar nuclei of dwarf galaxies. We present evidence that UCDs surrounding M87 and M49 may follow a morphological sequence ordered by the prominence of their outer, low surface brightness envelope, ultimately merging with the sequence of nucleated low-mass galaxies, and that envelope prominence correlates with distance from either galaxy. Our analysis provides evidence that tidal stripping of nucleated galaxies is an important process in the formation of UCDs.Comment: 37 pages, 40 figures. To appear in The Astrophysical Journa

    Temporal dynamics of hot desert microbial communities reveal structural and functional responses to water input

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    8 páginas, 4 figuras. -- The first publication is available at https://www.nature.comThe temporal dynamics of desert soil microbial communities are poorly understood. Given the implications for ecosystem functioning under a global change scenario, a better understanding of desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date (spatial variability) than over the course of one year (temporal variability). Community composition remained essentially unchanged across the first 10 months, indicating that spatial sampling might be more important than temporal sampling when assessing β-diversity patterns in desert soils. However, a major shift in microbial community composition was found following a single precipitation event. This shift in composition was associated with a rapid increase in CO2 respiration and productivity, supporting the view that desert soil microbial communities respond rapidly to re-wetting and that this response may be the result of both taxon-specific selection and changes in the availability or accessibility of organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one month after rainfall.We gratefully acknowledge financial support from the National Research Foundation of South Africa (grant no.81779 and TTK2008052000003), the Research Council of Norway (grant No. 180352) and the University of the Western Cape. Partial support was also provided under the Laboratory Directed Research and Development Program at PNNL, a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy under contract DE-AC05-76RL01830.Peer reviewe
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