12,726 research outputs found

    Intersexual conflict influences female reproductive success in a female-dispersing primate

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    In group-living mammals, individual efforts to maximize reproductive success result in conflicts and compromises between the sexes. Females utilize counterstrategies to minimize the costs of sexual coercion by males, but few studies have examined the effect of such behaviors on female reproductive success. Secondary dispersal by females is rare among group-living mammals, but in western gorillas, it is believed to be a mate choice strategy to minimize infanticide risk and infant mortality. Previous research suggested that females choose males that are good protectors. However, how much female reproductive success varies depending on male competitive ability and whether female secondary dispersal leads to reproductive costs or benefits has not been examined. We used data on 100 females and 229 infants in 36 breeding groups from a 20-year long-term study of wild western lowland gorillas to investigate whether male tenure duration and female transfer rate had an effect on interbirth interval, female birth rates, and offspring mortality. We found that offspring mortality was higher near the end of males’ tenures, even after excluding potential infanticide when those males died, suggesting that females suffer a reproductive cost by being with males nearing the end of their tenures. Females experience a delay in breeding when they dispersed, having a notable effect on birth rates of surviving offspring per female if females transfer multiple times in their lives. This study exemplifies that female counterstrategies to mitigate the effects of male-male competition and sexual coercion may not be sufficient to overcome the negative consequences of male behavior

    Uncertainties in Atmospheric Neutrino Fluxes

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    An evaluation of the principal uncertainties in the computation of neutrino fluxes produced in cosmic ray showers in the atmosphere is presented. The neutrino flux predictions are needed for comparison with experiment to perform neutrino oscillation studies. The paper concentrates on the main limitations which are due to hadron production uncertainties. It also treats primary cosmic ray flux uncertainties, which are at a lower level. The absolute neutrino fluxes are found to have errors of around 15% in the neutrino energy region important for contained events underground. Large cancellations of these errors occur when ratios of fluxes are considered, in particular, the νμ/νˉμ\nu_\mu/\bar{\nu}_\mu ratio below Eν=1E_\nu=1 GeV, the (νμ+νˉμ)/(νe+νˉe)(\nu_\mu+\bar{\nu}_\mu)/(\nu_e+\bar{\nu}_e) ratio below Eν=10E_\nu=10 GeV and the up/down ratios above Eν=1E_\nu=1 GeV are at the 1% level. A detailed breakdown of the origin of these errors and cancellations is presented.Comment: 14 pages, 22 postscript figures, written in Revte

    Association Between Combat, Morally Injurious Experiences, Spiritual Injury, and Alcohol Use Among Active Duty Military Personnel and Veterans

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    Literature has supported that, along with physical and psychological injuries, combat profoundly impacts veterans’ moral and spiritual belief systems and may contribute to negative health behaviors. Moral injury is a developing construct related to negative consequences associated with war-zone stressors that transgress military veterans’ deeply held values and belief systems. Additionally, spiritual injury addresses negative responses to an event that damages their relationship with God, self, and others, and alienates an individual from that which gives meaning to their lives. The purpose of the present study was to examine the relationship between combat exposure, morally injurious experiences (MIEs), spiritual injury, and hazardous alcohol use among U.S. active duty personnel, National Guard/Reserves, and veterans. Data were collected via online survey of 380 (260 men, 120 women) U.S. active duty personnel, National Guard/Reserves, and veterans. Participants completed the Combat Exposure Scale (CES; Keane et al., 1989), the Moral Injury Questionnaire – Military version (MIQ-M; Currier, Holland, Drescher, & Foy, 2015), the Spiritual Injury Scale (SIS; Berg, 1994), and the Alcohol Use Disorder Identification Test (AUDIT; Saunders, Aasland, Babor, de la Fuente, & Grant, 1993). Greater combat exposure, MIEs, and spiritual injuries were hypothesized to be positively associated with higher hazardous alcohol use. Additionally, both MIEs and spiritual injury were hypothesized to mediate the relationship between combat exposure and hazardous alcohol use. Further, a double mediation (combat exposure → MIEs → spiritual injury → hazardous alcohol use) was expected. Gender was also explored as a moderator of the mediated relationship between combat exposure, MIEs, and hazardous alcohol use. As expected, combat exposure, MIEs and spiritual injury were positively correlated with hazardous alcohol use. Results of a mediation analysis revealed that MIEs mediated the combat exposure-hazardous alcohol use relationship. However, spiritual injury did not significantly mediate the combat exposure-hazardous alcohol use relationship. A follow-up moderated mediation analysis revealed that gender significantly moderated the mediational path between combat exposure, MIEs, and hazardous alcohol use, such that the mediation was only significant among men. Results suggest that MIEs and spiritual injury are associated with hazardous alcohol use; however, MIEs may only explain the relationship between combat exposure and hazardous alcohol use for men. These results point to the importance of understanding how links between combat exposure, MIEs, and hazardous alcohol use may be nuanced by gender. Further, these results have implications for screening and trauma treatment among military members and veterans

    String spectra near some null cosmological singularities

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    We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We analyse string quantization to find the spectrum of string modes in these backgrounds. The classical string modes can be solved for exactly in these time-dependent backgrounds, which enables a detailed study of the near singularity string spectrum, (time-dependent) oscillator masses and wavefunctions. We find that for low lying string modes(finite oscillation number), the classical near-singularity string mode functions are non-divergent for various families of singularities. Furthermore, for any infinitesimal regularization of the vicinity of the singularity, we find a tower of string modes of ultra-high oscillation number which propagate essentially freely in the background. The resulting picture suggests that string interactions are non-negligible near the singularity.Comment: Latex, 30pgs; v2. minor clarifications, references adde

    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

    Modelling Gaia CCD pixels with Silvaco 3D engineering software

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    Gaia will only achieve its unprecedented measurement accuracy requirements with detailed calibration and correction for radiation damage. We present our Silvaco 3D engineering software model of the Gaia CCD pixel and two of its applications for Gaia: (1) physically interpreting supplementary buried channel (SBC) capacity measurements (pocket-pumping and first pixel response) in terms of e2v manufacturing doping alignment tolerances; and (2) deriving electron densities within a charge packet as a function of the number of constituent electrons and 3D position within the charge packet as input to microscopic models being developed to simulate radiation damage.Comment: 4 pages, 3 figures, contributed poster, appearing in proceedings of the ELSA conference: Gaia, at the frontiers of astrometry, 7-11 June 2010, S\`evres, Pari

    Holography and Cosmological Singularities

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    Certain null singularities in ten dimensional supergravity have natural holographic duals in terms of Matrix Theory and generalizations of the AdS/CFT correspondence. In many situations the holographic duals appear to be well defined in regions where the supergravity develops singularities. We describe some recent progress in this area.Comment: Anomaly equation corrected. References adde

    Dissecting the two mechanisms of scramble competition among the Virunga mountain gorillas

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    Two mechanisms have been proposed to explain why scramble competition can increase the travel requirements of individuals within larger groups. Firstly, individuals in larger groups may be more likely to encounter food sites where other group members have already eaten, leading to greater asynchronous “individual” travel to find fresh sites. Secondly, when food sites are aggregated into patches, larger groups may need to visit more patches to obtain the same amount of food per capita, leading to greater synchronous “group” travel between patches. If the first mechanism can be mitigated by increasing group spread, then we expect the second mechanism to be more sensitive to group size. Here, we examine the individual travel and group travel of the Virunga mountain gorillas, along with potential implications for the two mechanisms of scramble competition. Asynchronous individual travel accounted for 67% of the total travel time, and the remainder arose from group travel. Group spread increased significantly for larger groups, but not enough to prevent an increase in individual travel. Contrary to expectations, group travel decreased with size among most groups, and we found only limited evidence of patch depletion that would cause the second mechanism of scramble competition. Collectively, our results illustrate how the influence of group size can differ for individual travel versus group travel, just as it differs among species for overall travel. Studies that distinguish between the two mechanisms of scramble competition may enhance our understanding of ecological constraints upon group size, including potential differences between frugivores and folivores
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