1,543 research outputs found

    Data compressor Patent

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    Description of system for recording and reading out data related to distribution of occurrence of plurality of event

    Ytterbium divalency and lattice disorder in near-zero thermal expansion YbGaGe

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    While near-zero thermal expansion (NZTE) in YbGaGe is sensitive to stoichiometry and defect concentration, the NZTE mechanism remains elusive. We present x-ray absorption spectra that show unequivocally that Yb is nearly divalent in YbGaGe and the valence does not change with temperature or with nominally 1% B or 5% C impurities, ruling out a valence-fluctuation mechanism. Moreover, substantial changes occur in the local structure around Yb with B and C inclusion. Together with inelastic neutron scattering measurements, these data indicate a strong tendency for the lattice to disorder, providing a possible explanation for NZTE in YbGaGe.Comment: 4 pages, 4 figure, supplementary inf

    When Less is More: Mindfulness Predicts Adaptive Affective Responding to Rejection Via Reduced Prefrontal Recruitment

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    Social rejection is a distressing and painful event that many people must cope with on a frequent basis. Mindfulness—defined here as a mental state of receptive attentiveness to internal and external stimuli as they arise, moment-to-moment—may buffer such social distress. However, little research indicates whether mindful individuals adaptively regulate the distress of rejection—or the neural mechanisms underlying this potential capacity. To fill these gaps in the literature, participants reported their trait mindfulness and then completed a social rejection paradigm (Cyberball) while undergoing functional magnetic resonance imaging. Approximately 1 hour after the rejection incident, participants reported their level of distress during rejection (i.e. social distress). Mindfulness was associated with less distress during rejection. This relation was mediated by lower activation in the left ventrolateral prefrontal cortex during the rejection incident, a brain region reliably associated with the inhibition of negative affect. Mindfulness was also correlated with less functional connectivity between the left ventrolateral prefrontal cortex and the bilateral amygdala and the dorsal anterior cingulate cortex, which play a critical role in the generation of social distress. Mindfulness may relate to effective coping with rejection by not over-activating top-down regulatory mechanisms, potentially resulting in more effective long-term emotion-regulation

    Attachment style moderates partner presence effects on pain : A laser-evoked potentials study

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly citedSocial support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials to assess the effects of partner presence on subjective pain experience and underlying neural processes. Further, we examined whether individual differences in adult attachment style, alone or in interaction with the partner's level of attentional focus (manipulated to be either on or away from the participant) might modulate these effects. We found that the effects of partner presence versus absence on pain-related measures depended on adult attachment style but not partner attentional focus. The higher participants' attachment avoidance, the higher pain ratings and N2 and P2 local peak amplitudes were in the presence compared to the absence of the romantic partner. As laser-evoked potentials are thought to reflect activity relating to the salience of events, our data suggest that partner presence may influence the perceived salience of events threatening the body, particularly in individuals who tend to mistrust others.Peer reviewedFinal Published versio

    Resonant Inelastic X-Ray Scattering from Valence Excitations in Insulating Copper-Oxides

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    We report resonant inelastic x-ray measurements of insulating La2_2CuO4_4 and Sr2_2CuO2_2Cl2_2 taken with the incident energy tuned near the Cu K absorption edge. We show that the spectra are well described in a shakeup picture in 3rd order perturbation theory which exhibits both incoming and outgoing resonances, and demonstrate how to extract a spectral function from the raw data. We conclude by showing {\bf q}-dependent measurements of the charge transfer gap.Comment: minor notational changes, discussion of anderson impurity model fixed, references added; accepted by PR

    Quantum Monte Carlo calculation of Compton profiles of solid lithium

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    Recent high resolution Compton scattering experiments in lithium have shown significant discrepancies with conventional band theoretical results. We present a pseudopotential quantum Monte Carlo study of electron-electron and electron-ion correlation effects on the momentum distribution of lithium. We compute the correlation correction to the valence Compton profiles obtained within Kohn-Sham density functional theory in the local density approximation and determine that electronic correlation does not account for the discrepancy with the experimental results. Our calculations lead do different conclusions than recent GW studies and indicate that other effects (thermal disorder, core-valence separation etc.) must be invoked to explain the discrepancy with experiments.Comment: submitted to Phys. Rev.
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