752 research outputs found

    Enigma of ultraluminous X-ray sources may be resolved by 3D-spectroscopy (MPFS data)

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    The ultraluminous X-ray sources (ULXs) were isolated in external galaxies for the last 5 years. Their X-ray luminosities exceed 100-10000 times those of brightest Milky Way black hole binaries and they are extremely variable. There are two models for the ULXs, the best black hole candidates. 1. They are supercritical accretion disks around a stellar mass black hole like that in SS433, observed close to the disk axes. 2. They are Intermediate Mass Black Holes (of 100-10000 solar masses). Critical observations which may throw light upon the ULXs nature come from observations of nebulae around the ULXs. We present results of 3D-spectroscopy of nebulae around several ULXs located in galaxies at 3-6 Mpc distances. We found that the nebulae to be powered by their central black holes. The nebulae are shocked and dynamically perturbed probably by jets. The nebulae are compared with SS433 nebula (W50).Comment: Proceedings of the ESO and Euro3D Workshop "Science Perspectives for 3D Spectroscopy", Garching (Germany), October 10-14, 2005. M. Kissler-Patig, M.M. Roth and J.R. Walsh (eds.

    Statistical auditing and randomness test of lotto k/N-type games

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    One of the most popular lottery games worldwide is the so-called ``lotto k/N''. It considers N numbers 1,2,...,N from which k are drawn randomly, without replacement. A player selects k or more numbers and the first prize is shared amongst those players whose selected numbers match all of the k randomly drawn. Exact rules may vary in different countries. In this paper, mean values and covariances for the random variables representing the numbers drawn from this kind of game are presented, with the aim of using them to audit statistically the consistency of a given sample of historical results with theoretical values coming from a hypergeometric statistical model. The method can be adapted to test pseudorandom number generators.Comment: 10 pages, no figure

    Pre-treatment fertility preservation and post-treatment reproduction in long-term survivors of adolescent and young adult (AYA) cancer

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    Purpose: To describe recall of fertility-related consultations and cryopreservation and to examine reproductive goals and reproduction post-treatment in long-term survivors of adolescent and young adult (AYA) (age, 18–39 years) cancer. Methods: This study included n = 1457 male and n = 2112 female long-term survivors (M age = 43–45 years; 5–22 years from diagnosis) who provided self-report. Clinical data were supplied by the Netherlands Cancer Registry.Results: Most male survivors (72.7%) recalled fertility-related consultations and 22.6% completed sperm cryopreservation. Younger age (OR = 2.8; 95%CI [2.2–3.6]), not having children (OR = 5.0; 95%CI [3.2–7.7]), testicular cancer or lymphoma/leukemia (OR = 2.8/2.5 relative to “others”), and more intense treatments (OR = 1.5; 95%CI [1.1–2.0]) were associated with higher cryopreservation rates. Time since diagnosis had no effect. Of men who cryopreserved, 12.1% utilized assisted reproductive technologies (ART). Most men (88.5%) felt their diagnosis did not affect their reproductive goals, but 7.6% wanted no (additional) children due to cancer. Half of female survivors (55.4%; n = 1171) recalled fertility-related consultations. Rates of cryopreservation were very low (3.6%), but increased after 2013 when oocyte cryopreservation became non-experimental. Of women who cryopreserved, 13.2% successfully utilized ART. Most women (74.8%) experienced no effects of cancer on reproductive goals, but 17.8% wanted no (additional) children due to cancer. Conclusions: Cryopreservation in men varied by patient/clinical factors and was very low in women, but data of more recently treated females are needed. Utilizing cryopreserved material through ART was rare, which questions its cost-effectiveness, but it may enhance survivors’ well-being. Implications for Cancer Survivors: The extent to which cryopreservation positively affects survivors’ well-being remains to be tested. Moreover, effects of cancer on reproductive goals require further attention, especially in women who refrain from having children due to cancer.</p

    Pre-treatment fertility preservation and post-treatment reproduction in long-term survivors of adolescent and young adult (AYA) cancer

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    Purpose: To describe recall of fertility-related consultations and cryopreservation and to examine reproductive goals and reproduction post-treatment in long-term survivors of adolescent and young adult (AYA) (age, 18–39 years) cancer. Methods: This study included n = 1457 male and n = 2112 female long-term survivors (M age = 43–45 years; 5–22 years from diagnosis) who provided self-report. Clinical data were supplied by the Netherlands Cancer Registry.Results: Most male survivors (72.7%) recalled fertility-related consultations and 22.6% completed sperm cryopreservation. Younger age (OR = 2.8; 95%CI [2.2–3.6]), not having children (OR = 5.0; 95%CI [3.2–7.7]), testicular cancer or lymphoma/leukemia (OR = 2.8/2.5 relative to “others”), and more intense treatments (OR = 1.5; 95%CI [1.1–2.0]) were associated with higher cryopreservation rates. Time since diagnosis had no effect. Of men who cryopreserved, 12.1% utilized assisted reproductive technologies (ART). Most men (88.5%) felt their diagnosis did not affect their reproductive goals, but 7.6% wanted no (additional) children due to cancer. Half of female survivors (55.4%; n = 1171) recalled fertility-related consultations. Rates of cryopreservation were very low (3.6%), but increased after 2013 when oocyte cryopreservation became non-experimental. Of women who cryopreserved, 13.2% successfully utilized ART. Most women (74.8%) experienced no effects of cancer on reproductive goals, but 17.8% wanted no (additional) children due to cancer. Conclusions: Cryopreservation in men varied by patient/clinical factors and was very low in women, but data of more recently treated females are needed. Utilizing cryopreserved material through ART was rare, which questions its cost-effectiveness, but it may enhance survivors’ well-being. Implications for Cancer Survivors: The extent to which cryopreservation positively affects survivors’ well-being remains to be tested. Moreover, effects of cancer on reproductive goals require further attention, especially in women who refrain from having children due to cancer.</p

    Molecular Dynamics for Fermions

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    The time-dependent variational principle for many-body trial states is used to discuss the relation between the approaches of different molecular dynamics models to describe indistinguishable fermions. Early attempts to include effects of the Pauli principle by means of nonlocal potentials as well as more recent models which work with antisymmetrized many-body states are reviewed under these premises. Keywords: Many-body theory; Fermion system; Molecular dynamics; Wave-packet dynamics; Time-dependent variational principle; Statistical properties; Canonical ensemble; Ergodicity; Time averagingComment: 97 pages, 13 postscript figures. To be published in July 2000 issue of Reviews of Modern Physics. More information at http://www-aix.gsi.de/~fmd

    Quantum Rotation of HCN and DCN in Helium-4

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    We present calculations of rotational absorption spectra of the molecules HCN and DCN in superfluid helium-4, using a combination of the Diffusion Monte Carlo method for ground state properties and an analytic many-body method (Correlated Basis Function theory) for the excited states. Our results agree with the experimentally determined effective moment of inertia which has been obtained from the J=01J=0\to 1 spectral transition. The correlated basis function analysis shows that, unlike heavy rotors such as OCS, the J=2 and higher rotational excitations of HCN and DCN have high enough energy to strongly couple to rotons, leading to large shifts of the lines and accordingly to anomalous large spectroscopic distortion constants, to the emergence of roton-maxon bands, and to secondary peaks in the absorption spectra for J=2 and J=3.Comment: accepted by Phys. Rev. B; changes: included referee suggestions, removed typos, added 10 ref

    Elevated hematocrit enhances platelet accumulation following vascular injury

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    Red blood cells (RBCs) demonstrate procoagulant properties in vitro, and elevated hematocrit is associated with reduced bleeding and increased thrombosis risk in humans. These observations suggest RBCs contribute to thrombus formation. However, effects of RBCs on thrombosis are difficult to assess because humans and mice with elevated hematocrit typically have coexisting pathologies. Using an experimental model of elevated hematocrit in healthy mice, we measured effects of hematocrit in 2 in vivo clot formation models. We also assessed thrombin generation, platelet-thrombus interactions, and platelet accumulation in thrombi ex vivo, in vitro, and in silico. Compared with controls, mice with elevated hematocrit (RBCHIGH) formed thrombi at a faster rate and had a shortened vessel occlusion time. Thrombi in control and RBCHIGH mice did not differ in size or fibrin content, and there was no difference in levels of circulating thrombin-antithrombin complexes. In vitro, increasing the hematocrit increased thrombin generation in the absence of platelets; however, this effect was reduced in the presence of platelets. In silico, direct numerical simulations of whole blood predicted elevated hematocrit increases the frequency and duration of interactions between platelets and a thrombus.Whenhumanwhole blood was perfused over collagen at arterial shear rates, elevating the hematocrit increased the rate of platelet deposition and thrombus growth. These data suggest RBCs promote arterial thrombosis by enhancing platelet accumulation at the site of vessel injury. Maintaining a normal hematocrit may reduce arterial thrombosis risk in humans

    Biochar effect on the mineralization of soil organic matter

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    The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM). In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and nonsignificant. Without biochar, 48±0.2% of the straw carbon was mineralized within the 451 days of the experiment. In comparison, 45±1.6% of C was mineralized after biochar addition of 1.5 g kg-1. In the SOM-labelled soil, the organic matter mineralized more slowly with the increasing doses of biochar. Biochar addition at 7.7 g kg-1 reduced SOM mineralization from 6.6 to 6.3%, during the experimental period. The addition of 15.5 g kg-1 of biochar reduced the mineralized SOM to 5.7%. There is no evidence of increased degradation of either litter or SOM due to biochar addition; consequently, there is no evidence of decreased stability of SOM

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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