4,174 research outputs found

    Entanglement Generation in the Scattering of One-Dimensional Particles

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    This article provides a convenient framework for quantitative evaluation of the entanglement generated when two structureless, distinguishable particles scatter non-relativistically in one dimension. It explores how three factors determine the amount of entanglement generated: the momentum distributions of the incoming particles, their masses, and the interaction potential. Two important scales emerge, one set by the kinematics and one set by the dynamics. This method also provides two approximate analytic formulas useful for numerical evaluation of entanglement and reveals an interesting connection between purity, linear coordinate transformations, and momentum uncertainties.Comment: 11 pages, submitted to PR

    Local magnitudes and apparent variations in seismicity rates in Southern California

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    Redetermination of local magnitudes for moderate earthquakes recorded by the Southern California Seismographic Network (SCSN) from 1932 to 1990 has shown that the magnitudes have not been consistently determined over that time period. The amplitudes of ground velocities recorded on Wood-Anderson instruments were systematically overestimated prior to 1944 compared to present reading procedures, leading to a significant overestimation of local magnitudes. In addition, the change from human to computerized estimation of event magnitude from a suite of amplitudes in 1975 led to slightly lower event magnitudes for the time after 1975 compared to the time before. These changes contribute to an apparently higher rate of seismicity in the 1930s and 1940s than later in the catalog, which had been interpreted as a decrease in seismicity rate after the 1952 Kern County (M_w 7.5) earthquake. Wood-Anderson amplitudes have been reread and consistent magnitudes recalculated using uniform procedures for all earthquakes with a catalog magnitude of 4.5 and greater within the SCSN from 1932 to 1943 and those with a catalog magnitude of 4.8 and greater from 1944 to 1990 so as to create a complete list of all earthquakes with a modern local magnitude of 5.0 or greater. Using these new magnitudes, we find that the rate of M_L 5.0 and greater earthquakes in southern California over this 59-year period to be Poissonian, with no changes in rate significant above the 90% level. From this rate, in any 30-year period, the Poissonian probability of a M ≧ 6 earthquake is 99.7%, the probability of an M ≧ 7 earthquake is 65%, and the probability of an M ≧ 8 event is 18%

    Happiness as stable extraversion : internal consistency reliability and construct validity of the Oxford Happiness Questionnaire among undergraduate students

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    The Oxford Happiness Questionnaire (OHQ) was developed by Hills and Argyle (2002) to provide a more accessible equivalent measure of the Oxford Happiness Inventory (OHI). The aim of the present study was to examine the internal consistency reliability, and construct validity of this new instrument alongside the Eysenckian dimensional model of personality. The Oxford Happiness Questionnaire was completed by a sample of 131 undergraduate students together with the abbreviated form of the Revised Eysenck Personality Questionnaire. The data demonstrated good internal consistency reliability (alpha = .92) and good construct validity in terms of positive association with extraversion (r = .38 p < .001) and negative association with neuroticism (r = −.57 p < .001). The kind of happiness measured by the OHQ is clearly associated with stable extraversion

    Executive function in first-episode schizophrenia

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    BACKGROUND: We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-episode patients. Previous studies have shown either equal decrements in many cognitive domains or specific deficits in memory. Such studies have grouped test results or have used few executive measures, thus, possibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function. METHODS: Thirty first-episode schizophrenic patients and 30 normal volunteers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from the Cambridge Automated Neuropsychological Test Battery. Computerized and traditional tests of memory were also administered for comparison. RESULTS: Patients were worse on all tests but the profile was non-uniform. A componential analysis indicated that the patients were characterized by a poor ability to think ahead and organize responses but an intact ability to switch attention and inhibit prepotent responses. Patients also demonstrated poor memory, especially for free recall of a story and associate learning of unrelated word pairs. CONCLUSIONS: In contradistinction to previous studies, schizophrenic patients do have profound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set shifting, which is generally unimpaired. Previous findings in more chronic patients, of severe attentional set shifting impairment, suggest that executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first episode suggests that cognitive deficits are not restricted to one cognitive domain

    The first confirmation of V-type asteroids among the Mars crosser population

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    The Mars crossing region constitutes a path to deliver asteroids from the Inner Main Belt to the Earth crossing space. While both the Inner Main Belt and the population of Earth crossing asteroids contains a significant fraction of asteroids belonging to the V taxonomic class, only two of such V-type asteroids has been detected in the Mars crossing region up to now. In this work, we searched for asteroids belonging to the V class among the population of Mars crossing asteroids, in order to support alternative paths to the delivery of this bodies into the Earth crossing region. We selected 18 candidate V-type asteroids in the Mars crossing region using observations contained in the Sloan Digital Sky Survey Moving Objects Catalog. Then, we observed 4 of these candidates to take their visible spectra using the Southern Astrophysical Research Telescope (SOAR). We also performed the numerical simulation of the orbital evolution of the observed asteroids. We confirmed that 3 of the observed asteroids belong to the V class, and one of these may follow a path that drives it to an Earth collision in some tens of million years

    Susceptibility of Vitis vinifera 'Semillon' and 'Chardonnay' to the root-knot nematode Meloidogyne javanica

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    A study to assess the effect of the initial population (Pi) densities (0, 200, 400, 600 and 800 second stage juveniles (J2) kg-1 dry soil) of the root knot nematode, Meloidogyne javanica, on the growth, yield and juice characteristics of two white wine grapevine (Vitis vinifera) cvs. 'Semillon' and 'Chardonnay' was conducted in a vineyard located at the Centre for Irrigated Agriculture, Riverina, NSW, Australia. M. javanica J2 population densities in soil after harvest during 2004-2008 growing seasons increased gradually, year by year, and in most cases were higher where the initial densities were higher. Regression analysis revealed that yield, in general, was reduced significantly with the increase of the nematode population densities·kg-1 soil for both cultivars. After six years, the nematode population had increased by ca. 9.0-22.4 fold for 'Semillon' and 6.7-18.5 fold for 'Chardonnay'. All Pi densities significantly reduced Semillon yields in all years but only the highest level (800 J2·kg-1 dry soil) affected 'Chardonnay' yields. At the end of the experiment, M. javanica decreased yields by 15-20 % in Semillon but only 7-13 % in 'Chardonnay'. The nematode inoculation also caused a decrease in bunch numbers in 'Semillon' but not in 'Chardonnay'. This is the first study showing that 'Chardonnay' is less susceptible to M. javanica than 'Semillon'.

    The 3 December 1988 Pasadena, California earthquake: Evidence for strike-slip motion on the Raymond fault

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    The Pasadena earthquake (M_L = 4.9) occurred on 3 December 1988, at a depth of 16 km. The hypocenters of the earthquake and its aftershocks define a east-northeast striking, steeply northwest-dipping surface that projects up to the active surficial trace of the Raymond fault. One of the nodal planes of the focal mechanism of the earthquake parallels the Raymond fault with left-lateral strike-slip movement on that plane, and is consistent with geomorphic and paleoseismic evidence that the Raymond fault is dominantly a left-lateral strike-slip fault. The existence of a component of sinistral slip along the Raymond fault had been suspected prior to the earthquake, but the northward dip of the fault and the prominent scarp along the western portion of its trace had led most workers to conclude that slip along the fault was dominantly reverse

    Ultrafast Photoinduced Dynamics of 1,3-Cyclohexadiene Using XMS-CASPT2 Surface Hopping

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    A full-dimensional simulation of the photodissociation of 1,3-cyclohexadiene in the manifold of three electronic states was performed via nonadiabatic surface hopping dynamics using extended multistate complete active space second-order perturbation (XMS-CASPT2) electronic structure theory with fully analytic nonadiabatic couplings. With the 47 ± 8% product quantum yield calculated from the 136 trajectories, generally 400 fs-long, and an estimated excited lifetime of 89 ± 9 fs, our calculations provide a detailed description of the nonadiabatic deactivation mechanism, showing the existence of an extended conical intersection seam along the reaction coordinate. The nature of the preferred reaction pathways on the ground state is discussed and extensive comparison to the previously published full dimensional dynamics calculations is provided

    Influence of Body Weight Category on Outcomes in Candidemia Patients Treated With Anidulafungin

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    BACKGROUND: Case reports and pharmacokinetic data suggest off-label echinocandin dosing may be needed to reach adequate serum concentrations in obese patients. Few outcome studies exist evaluating this population. OBJECTIVES: Of this study were to (1) determine the association of body mass index (BMI) with clinical outcomes of candidemia patients on standard doses of anidulafungin and (2) characterize fungal infections by body weight. METHODS: A retrospective cohort was conducted to evaluate hospitalized patients treated for candidemia with anidulafungin at Food and Drug Administration-labeled dosing for at least 72 hours from January 1, 2014, through January 31, 2018. Candidemia was diagnosed by blood culture or T2 magnetic resonance (T2MR). Patients were compared according to BMI category. RESULTS: One hundred seventy-three patients were included. CONCLUSION: There was no difference detected in mortality among patients with candidemia across BMI category. Larger studies are needed to confirm whether standard doses of anidulafungin are sufficient for candidemia in obese patients
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