17,540 research outputs found

    Understanding the truth about subjectivity

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    Results of two experiments show children’s understanding of diversity in personal preference is incomplete. Despite acknowledging diversity, in Experiment 1(N=108), 6- and 8-year-old children were less likely than adults to see preference as a legitimate basis for personal tastes and more likely to say a single truth could be found about a matter of taste. In Experiment 2 (N=96), 7- and 9-year-olds were less likely than 11- and 13-yearolds to say a dispute about a matter of preference might not be resolved. These data suggest that acceptance of the possibility of diversity does not indicate an adult-like understanding of subjectivity. An understanding of the relative emphasis placed on objective and subjective factors in different contexts continues to develop into adolescence

    Radiation processes and the distribution of radiative sources and sinks

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    Atmospheric models of radiative processes, sources, and sinks in mesosphere and thermospher

    The new HiVIS spectropolarimeter and spectropolarimetric calibration of the AEOS telescope

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    We designed, built, and calibrated a new spectropolarimeter for the HiVIS spectrograph (R 12000-49000) on the AEOS telescope. We also did a polarization calibration of the telescope and instrument. We will introduce the design and use of the spectropolarimeter as well as a new data reduction package we have developed, then discuss the polarization calibration of the spectropolarimeter and the AEOS telescope. We used observations of unpolarized standard stars at many pointings to measure the telescope induced polarization and compare it with a Zemax model. The telescope induces polarization of 1-6% with a strong variation with wavelength and pointing, consistent with the altitude and azimuth variation expected. We then used scattered sunlight as a linearly polarized source to measure the telescopes spectropolarimetric response to linearly polarized light. We then made an all-sky map of the telescope's polarization response to calibrate future spectropolarimetry.Comment: PASP 118, June 200

    Disgust implicated in obsessive-compulsive disorder

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    Psychiatric classificatory systems consider obsessions and compulsions as forms of anxiety disorder. However, the neurology of diseases associated with obsessive-compulsive symptoms suggests the involvement of fronto-striatal regions likely to be involved in the mediation of the emotion of disgust, suggesting that dysfunctions of disgust should be considered alongside anxiety in the pathogenesis of obsessive-compulsive behaviours. We therefore tested recognition of facial expressions of basic emotions (including disgust) by groups of participants with obsessive-compulsive disorder (OCD) and with Gilles de la Tourette's syndrome (GTS) with and without co-present obsessive-compulsive behaviours (GTS with OCB; GTS without OCB). A group of people suffering from panic disorder and generalized anxiety were also included in the study. Both groups with obsessive-compulsive symptoms (OCD; GTS with OCB) showed impaired recognition of facial expressions of disgust. Such problems were not evident in participants with panic disorder and generalized anxiety, or for participants with GTS without obsessions or compulsions, indicating that the deficit is closely related to the presence of obsessive-compulsive symptoms. Participants with OCD were able to assign words to emotion categories without difficulty, showing that their problem with disgust is linked to a failure to recognize this emotion in others and not a comprehension or response criterion effect. Impaired recognition of disgust is consistent with the neurology of OCD and with the idea that abnormal experience of disgust may be involved in the genesis of obsessions and compulsions

    Radiative Decay of Vector Quarkonium: Constraints on Glueballs and Light Gluinos

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    Given a resonance of known mass, width, and J^{PC}, we can determine its gluonic branching fraction, b(R->gg), from data on its production in radiative vector quarkonium decay, V -> gamma+R. For most resonances b(R->gg) is found to be O(10%), consistent with being q-qbar states, but we find that both pseudoscalars observed in the 1440 MeV region have b(R->gg) ~ 1/2 - 1, and b(f_0^{++}->gg) ~ 1/2. As data improves, b(R->gg) should be a useful discriminator between q-qbar and gluonic states and may permit quantitative determination of the extent to which a particular resonance is a mixture of glueball and q-qbar. We also examine the regime of validity of pQCD for predicting the rate of V -> gamma+eta_gluino, the ``extra'' pseudoscalar bound state which would exist if there were light gluinos. From the CUSB limit on peaks in Upsilon -> gamma X, the mass range 3 GeV < m(eta_gluino) < 7 GeV can be excluded. An experiment must be significantly more sensitive to exclude an eta_gluino lighter than this.Comment: 36pp (inc figs),RU-94-04. (Replaces original which didn't latex correctly and didn't have figures.

    Behaviors of Adult \u3ci\u3eAgrilus Planipennis\u3c/i\u3e (Coleoptera: Buprestidae)

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    A 2-year study was conducted in Canada (2003) and the United States (2005) to better understand searching and mating behaviors of adult Agrilus planipennis Fairmaire. In both field and laboratory, adults spent more time resting and walking than feeding or flying. The sex ratio in the field was biased towards males, which tended to hover around trees, likely looking for mates. There was more leaf feeding damage within a tree higher in the canopy than in the lower canopy early in the season, but this difference disappeared over time. In choice experiments, males attempted to mate with individuals of both sexes, but they landed more frequently on females than on males. A series of sexual behaviors was observed in the laboratory, including: exposure of the ovipositor/genitalia, sporadic jumping by males, attempted mating, and mating. Sexual behaviors were absent among 1-3 day-old beetles, but were observed regularly in 10-12 day-old beetles. Females were seen exposing their ovipositor, suggestive of pheromone-calling behavior. No courtship was observed prior to mating. Hovering, searching, and landing behaviors suggest that beetles most likely rely on visual cues during mate finding, although host-plant volatiles and/or pheromones might also be involved

    Electroweak Sudakov Logarithms and Real Gauge-Boson Radiation in the TeV Region

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    Electroweak radiative corrections give rise to large negative, double-logarithmically enhanced corrections in the TeV region. These are partly compensated by real radiation and, moreover, affected by selecting isospin-noninvariant external states. We investigate the impact of real gauge boson radiation more quantitatively by considering different restricted final state configurations. We consider successively a massive abelian gauge theory, a spontaneously broken SU(2) theory and the electroweak Standard Model. We find that details of the choice of the phase space cuts, in particular whether a fraction of collinear and soft radiation is included, have a strong impact on the relative amount of real and virtual corrections.Comment: 20 pages, 4 figure

    Microscopic theory of quantum-transport phenomena in mesoscopic systems: A Monte Carlo approach

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    A theoretical investigation of quantum-transport phenomena in mesoscopic systems is presented. In particular, a generalization to ``open systems'' of the well-known semiconductor Bloch equations is proposed. The presence of spatial boundary conditions manifest itself through self-energy corrections and additional source terms in the kinetic equations, whose form is suitable for a solution via a generalized Monte Carlo simulation. The proposed approach is applied to the study of quantum-transport phenomena in double-barrier structures as well as in superlattices, showing a strong interplay between phase coherence and relaxation.Comment: to appear in Phys. Rev. Let

    A multiscale DEM-LBM analysis on permeability evolutions inside a dilatant shear band

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    This paper presents a multiscale analysis of a dilatant shear band using a three-dimensional discrete element method and a lattice Boltzmann/finite element hybrid scheme. In particular, three-dimensional simple shear tests are conducted via the discrete element method. A spatial homogenization is performed to recover the macroscopic stress from the micro-mechanical force chains. The pore geometries of the shear band and host matrix are quantitatively evaluated through morphology analyses and lattice Boltzmann/finite element flow simulations. Results from the discrete element simulations imply that grain sliding and rotation occur predominately with the shear band. These granular motions lead to dilation of pore space inside the shear band and increases in local permeability. While considerable anisotropy in the contact fabric is observed with the shear band, anisotropy of the permeability is, at most, modest in the assemblies composed of spherical grains

    Structural Transition Kinetics and Activated Behavior in the Superconducting Vortex Lattice

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    Using small-angle neutron scattering, we investigated the behavior of a metastable vortex lattice state in MgB2 as it is driven towards equilibrium by an AC magnetic field. This shows an activated behavior, where the AC field amplitude and cycle count are equivalent to, respectively, an effective "temperature" and "time". The activation barrier increases as the metastable state is suppressed, corresponding to an aging of the vortex lattice. Furthermore, we find a cross-over from a partial to a complete suppression of metastable domains depending on the AC field amplitude, which may empirically be described by a single free parameter. This represents a novel kind of collective vortex behavior, most likely governed by the nucleation and growth of equilibrium vortex lattice domains.Comment: 5 pages plus 3 pages of supplemental materia
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