1,801 research outputs found

    Measurement of the Double Longitudinal Spin Asymmetry in Inclusive Jet Production in Polarized p-p Collisions at √s = 200 GeV at STAR

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    One of the primary goals of the STAR spin program at RHIC is the measurement of the double longitudinal asymmetry ALL in inclusive jet production. This measurement will allow STAR to determine the polarized gluon distribution function DeltaG in the Bjorken x region of 0.03<x<0.3. Inclusive jet production is a theoretically desirable way to measure DeltaG, as it is independent of fragmentation functions. This contribution presents STAR's preliminary 2005 measurements of ALL for inclusive jet production extracted from 3.1 pb−1 of data at [square root of]s=200 GeV and 50% beam polarization. The asymmetry is calculated over the transverse momentum region 5 < pT < 30 GeV/c and compared with theoretical predictions incorporating several gluon polarization scenarios. Systematic uncertainties from false asymmetries, jet reconstruction, and triggering are discussed. At the present level of statistics, the measured asymmetry disfavors maximal gluon polarization but cannot yet distinguish between other theoretical scenarios

    The Lover\u27s Cup

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    This documentary film, The Lover\u27s Cup is the story of a former Naval Officer from World War II, Dr. Phillip Trapp, who took Marines into the battle of Iwo Jima and lived to see the flag being raised on Mt. Suribachi. This 55-minute film explores his life experiences before, during and following World War II. His first-hand experiences are used to illustrate the Social and psychological impact of the Great Depression and World War II and his journey to overcome his adversity and create positive changes in the world through his subsequent education and service at the University of Arkansas and the community of Northwest Arkansas. The Lover\u27s Cup explores some of the factors, which helped shape what many have called The Greatest Generation. It also addresses the political and psychological ramifications of World War II and it\u27s differences to modern day world conflict. The film includes several interviews over the course of two years with Dr. Trapp. It also includes some re-enactments and extensive archival footage and photographs through the National Archives and Library of Congress. This is a character-driven narrative, using the Great Depression and World War II as vehicles to tell the story. The goal of this film is to help generate a renewed awareness, understanding and appreciation of the Greatest Generation, who will all soon be gone

    THE ART OF WAR: PATTERNS AND MECHANISMS UNDERLYING PREDATOR-INDUCED PLASTICITY OF AMPHIBIANS

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    Organisms often employ phenotypic plasticity as a strategy to cope with variable environments. This is particularly true of predation threats, wherein prey induce defenses to reduce detection or capture by predators. In order to produce appropriate defenses, prey must be able to discern useful information from environmental cues. Despite the pervasive production of inducible defenses, we understand very little of how much useful information is conveyed to organisms in cues, or how the subsequent plastic responses vary within groups of organisms. To address the need for comparative studies of phenotypic plasticity, we sought to examine morphological and behavioral defenses of five species of Ambystoma salamander larvae in response to larval dragonfly (Anax junius) chemical cues in a common garden environment. Dragonfly cues induced relatively few morphological changes across species. Likewise, salamanders did not vary in their refuge use during the experiment, though several species reduced their activity in the presence of predators early in development. Our results suggest that behavioral and morphological defenses in Ambystoma are highly variable among species and the genus appears to be less plastic than tadpoles and other salamander species. To understand what types of information prey are capable of responding to in their environment, we raised grey treefrog tadpoles (Hyla verisciolor) in the presence of cues isolated from different stages of an attack sequence by larval dragonflies (A. junius) or larval dragonflies THE ART OF WAR: PATTERNS AND MECHANISMS UNDERLYING PREDATOR-INDUCED PLASTICITY OF AMPHIBIANS Heather Michelle Shaffery, M.S. University of Pittsburgh, 2013 iv consuming different combinations of grey treefrog tadpoles and snails (Helisoma trivolvis) across different temporal sequences. When exposed to a predator consuming grey treefrogs, tadpoles reduced their activity, increased their hiding behavior, and induced deeper tails. As we exposed prey to more types of cues from an attack sequence, they also increased tail depth and hiding behavior but did not change their activity. Additionally, treefrog tadpoles generally increased their defense as the biomass of treefrogs consumed increased, regardless of whether heterospecifics were being consumed. Our results suggest that treefrogs can gain cue information from all portions of an attack sequence, and that both temporal patterns of feeding and diet content of predators influence the type and magnitude of induced prey defenses

    The energy dependence of p_t angular correlations inferred from mean-p_t fluctuation scale dependence in heavy ion collisions at the SPS and RHIC

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    We present the first study of the energy dependence of pt angular correlations inferred from event-wisemean transverse momentum (pt) fluctuations in heavy ion collisions. We compare our large-acceptancemeasurements at CM energies √^sNN = 19.6, 62.4, 130 and 200 GeV to SPS measurements at 12.3 and 17.3 GeV. p_t angular correlation structure suggests that the principal source of p_t correlations and fluctuations is minijets (minimum-bias parton fragments). We observe a dramatic increase in correlations and fluctuations from SPS to RHIC energies, increasing linearly with ln √^sNN from the onset of observable jet-related (p_t) fluctuations near 10 GeV

    Two-particle correlations on transverse momentum and momentum dissipation in Au–Au collisions at √sNN = 130 GeV

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    Measurements of two-particle correlations on transverse momentum p_t for Au–Au collisions at √^sNN = 130 GeV are presented. Significant largemomentum-scale correlations are observed for charged primary hadrons with 0.15 ≤ p_t ≤ 2 GeV/c and pseudorapidity |η| ≤ 1.3. Such correlations were not observed in a similar study at lower energy and are not predicted by theoretical collision models. Their direct relation to mean-p_t fluctuations measured in the same angular acceptance is demonstrated. Positive correlations are observed for pairs of particles which have large pt values while negative correlations occur for pairs in which one particle has large p_t and the other has much lower p_t . The correlation amplitudes per final state particle increase with collision centrality. The observed correlations are consistent with a scenario in which the transverse momentum of hadrons associated with initial-stage semi-hard parton scattering is dissipated by the medium to lower p_t

    Improving Omnidirectional Camera-Based Robot Localization Through Self-Supervised Learning

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    Autonomous agents in any environment require accurate and reliable position and motion estimation to complete their required tasks. Many different sensor modalities have been utilized for this task such as GPS, ultra-wide band, visual simultaneous localization and mapping (SLAM), and light detection and ranging (LiDAR) SLAM. Many of the traditional positioning systems do not take advantage of the recent advances in the machine learning field. In this work, an omnidirectional camera position estimation system relying primarily on a learned model is presented. The positioning system benefits from the wide field of view provided by an omnidirectional camera. Recent developments in the self-supervised learning field for generating useful features from unlabeled data are also assessed. A novel radial patch pretext task for omnidirectional images is presented in this work. The resulting implementation will be a robot localization and tracking algorithm that can be adapted to a variety of environments such as warehouses and college campuses. Further experiments with additional types of sensors including 3D LiDAR, 60 GHz wireless, and Ultra-Wideband localization systems utilizing machine learning are also explored. A fused learned localization model utilizing multiple sensor modalities is evaluated in comparison to individual sensor models

    Victorianizing Guangxu: Arresting Flows, Minting Coins, and Exerting Authority in Early Twentieth-Century Kham

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    In the late Qing and early Republican eras, eastern Tibet (Kham) was a borderland on the cusp of political and economic change. Straddling Sichuan Province and central Tibet, it was coveted by both Chengdu and Lhasa. Informed by an absolutist conception of territorial sovereignty, Sichuan officials sought to exert exclusive authority in Kham by severing its inhabitants from regional and local influence. The resulting efforts to arrest the flow of rupees from British India and the flow of cultural identity entwined with Buddhism from Lhasa were grounded in two misperceptions: that Khampa opposition to Chinese rule was external, fostered solely by local monasteries as conduits of Lhasa’s spiritual authority, and that Sichuan could arrest such influence, the absence of which would legitimize both exclusive authority in Kham and regional assertions of sovereignty. The intersection of these misperceptions with the significance of Buddhism in Khampa identity determined the success of Sichuan’s policies and the focus of this article, the minting and circulation of the first and only Qing coin emblazoned with an image of the emperor. It was a flawed axiom of state and nation builders throughout the world that severing local cultural or spiritual influence was possible—or even necessary—to effect a borderland’s incorporation. Keywords: Sichuan, southwest China, Tibet, currency, Indian rupee, territorial sovereignty, Qing borderland

    Covariance Analysis of Vision Aided Navigation by Bootstrapping

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    Inertial Navigation System (INS) aiding using bearing measurements taken over time of stationary ground features is investigated. A cross country flight, in two and three dimensional space, is considered, as well as a vertical drop in three dimensional space. The objective is to quantify the temporal development of the uncertainty in the navigation states of an aircraft INS which is aided by taking bearing measurements of ground objects which have been geolocated using ownship position. It is shown that during wings level flight at constant speed and a fixed altitude, an aircraft that tracks ground objects and over time sequentially transitions to tracking new ground objects which were geolocated by the aircraft as they came into view, will have the beneficial effect of considerably reducing the long term uncertainty in the INS-provided navigation state. It is also shown that a munition in free fall tracking previously geolocated ground features will also have the beneficial effect of reducing the uncertainty in the INS-provided navigation state
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