1,969 research outputs found

    Ownership-dependent mating tactics of minor males of the beetle Librodor japonicus (Nitidulidae) with intra-sexual dimorphism of mandibles

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    Intra-sexual dimorphism is found in the weapons of many male beetles. Different behavioral tactics to access females between major and minor males, which adopt fighting and alternative tactics, respectively, are thought to maintain the male dimorphism. In these species major males have enlarged weapons that they use in fights with rival males. Minor males also have small weapons in some of these species, and it is unclear why these males possess weapons. We examined the hypothesis that minor males might adopt a fighting tactic when their status was relatively high in comparison with that of other males (e.g., ownership of a territory). We observed the behavioral tactics of major and minor males of the beetle Librodor japonicus, whose males have a dimorphism of their mandibles. Major males fought for resources, whereas minor males adopted two status-dependent tactics, fighting and sneaking, to access females, depending on their ownership of a sap site. We suggest that ownership status-dependent mating tactics in minor males may maintain the intra-sexual dimorphism in this beetle.</p

    The coin beneath the crust : a pilot study of coins from the Mediterranean coast of Israel

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    We describe the application of synchrotron X-ray diffraction and neutron micro-tomography to three ancient bronze coins from the Mediterranean coast of Israel. Key questions are whether neutron tomography can contribute to the reading of features on corroded coins by allowing the corrosion crust to be stripped away in cyber-space using surface and volume rendering techniques, and to what extent this type of non-destructive measurement can inform possible conservation action. In addition, the X-ray diffraction experiments allow the main composition of the varicoloured surface corrosion to be deduced. We show that both X-ray and neutron data are of considerable help to numismatic study of the coins

    Strict detector-efficiency bounds for n-site Clauser-Horne inequalities

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    An analysis of detector-efficiency in many-site Clauser-Horne inequalities is presented, for the case of perfect visibility. It is shown that there is a violation of the presented n-site Clauser-Horne inequalities if and only if the efficiency is greater than n/(2n-1). Thus, for a two-site two-setting experiment there are no quantum-mechanical predictions that violate local realism unless the efficiency is greater than 2/3. Secondly, there are n-site experiments for which the quantum-mechanical predictions violate local realism whenever the efficiency exceeds 1/2.Comment: revtex, 5 pages, 1 figure (typesetting changes only

    Prenatal insomnia and childbirth-related PTSD symptoms: A prospective population-based cohort study.

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    Certain populations are at high risk of experiencing a traumatic event and developing post-traumatic stress disorder (PTSD). Yet, primary preventive interventions against PTSD are lacking. It is therefore crucial to identify pre-traumatic risk factors, which could be targeted with such interventions. Insomnia may be a good candidate, but studies on civilians are sparse. Furthermore, the mechanisms at stake in the relationship between pre-traumatic insomnia and PTSD symptoms are unclear. This prospective population-based cohort study (n = 1,610) examined the relationship between insomnia symptoms at 32 weeks of pregnancy and childbirth-related PTSD (CB-PTSD) symptoms at eight weeks postpartum. Postnatal insomnia symptoms, prenatal psychological symptoms (depression, anxiety, PTSD, fear of childbirth), subjective birth experience (SBE) and birth medical severity were included as covariates in the analyses, which were based on a Piecewise Structural Equation Modelling approach. The relationship between prenatal insomnia and CB-PTSD symptoms was mediated by negative SBE and postnatal insomnia symptoms. All relationships involving insomnia symptoms had small or very small effect sizes. This study used self-report questionnaires. Postnatal insomnia and CB-PTSD symptoms were concurrently measured. Prenatal insomnia symptoms may impair the ability to cope with a difficult birth experience and contribute to postnatal insomnia, a risk factor for CB-PTSD. Thus, prenatal insomnia symptoms may be a promising target for CB-PTSD primary preventive interventions, although other prenatal psychological symptoms could also be considered. Even beyond the perinatal context, future studies on pre-traumatic insomnia and PTSD should include post-traumatic insomnia as a covariate

    Non-Locality and Theories of Causation

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    The aim of the paper is to investigate the characterization of an unambiguous notion of causation linking single space-llike separated events in EPR-Bell frameworks. This issue is investigated in ordinary quantum mechanics, with some hints to no collapse formulations of the theory such as Bohmian mechanics.Comment: Presented at the NATO Advanced Research Workshop on Modality, Probability and Bell's Theorems, Cracow, Poland, August 19-23, 200

    The Conway-Kochen argument and relativistic GRW models

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    In a recent paper, Conway and Kochen proposed what is now known as the "Free Will theorem" which, among other things, should prove the impossibility of combining GRW models with special relativity, i.e., of formulating relativistically invariant models of spontaneous wavefunction collapse. Since their argument basically amounts to a non-locality proof for any theory aiming at reproducing quantum correlations, and since it was clear since very a long time that any relativistic collapse model must be non-local in some way, we discuss why the theorem of Conway and Kochen does not affect the program of formulating relativistic GRW models.Comment: 16 pages, RevTe

    Human Challenge Pilot Study with Cyclospora cayetanensis

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    We describe a pilot study that attempted to infect human volunteers with Cyclospora cayetanensis. Seven healthy volunteers ingested an inoculum of Cyclospora oocysts (approximately 200–49,000 oocysts). The volunteers did not experience symptoms of gastroenteritis, and no oocysts were detected in any stool samples during the 16 weeks volunteers were monitored

    Coexistence of Quantum Theory and Special Relativity in signaling scenarios

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    The coexistence between Quantum Mechanics and Special Relativity is usually formulated in terms of the no-signaling condition. Several authors have even suggested that this condition should be included between the basic postulates of Quantum Theory. However, there are several scenarios where signaling is, in principle, possible: based on previous results and the analysis of the relation between unitarity and signaling we present an example of a two-particle interferometric arrangement for which the dynamics is, in principle, compatible with superluminal transmission of information. This type of non-locality is not in the line of Bell's theorem, but closer in spirit to the one-particle acausality studied by Hegerfeldt and others. We analyze in this paper the meaning of this non-locality and how to preserve the coexistence of the two fundamental theories in this signaling scenario.Comment: See also the comment by G C Hegerfeldt in the online version of the journal, including more reference

    Remote sensing data from CLARET: A prototype CART data set

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    The data set containing radiation, meteorological , and cloud sensor observations is documented. It was prepared for use by the Department of Energy's Atmospheric Radiation Measurement (ARM) Program and other interested scientists. These data are a precursor of the types of data that ARM Cloud And Radiation Testbed (CART) sites will provide. The data are from the Cloud Lidar And Radar Exploratory Test (CLARET) conducted by the Wave Propagation Laboratory during autumn 1989 in the Denver-Boulder area of Colorado primarily for the purpose of developing new cloud-sensing techniques on cirrus. After becoming aware of the experiment, ARM scientists requested archival of subsets of the data to assist in the developing ARM program. Five CLARET cases were selected: two with cirrus, one with stratus, one with mixed-phase clouds, and one with clear skies. Satellite data from the stratus case and one cirrus case were analyzed for statistics on cloud cover and top height. The main body of the selected data are available on diskette from the Wave Propagation Laboratory or Los Alamos National Laboratory
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