9,399 research outputs found

    Current and future graphics requirements for LaRC and proposed future graphics system

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    The findings of an investigation to assess the current and future graphics requirements of the LaRC researchers with respect to both hardware and software are presented. A graphics system designed to meet these requirements is proposed

    Evanescent single-molecule biosensing with quantum limited precision

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    Sensors that are able to detect and track single unlabelled biomolecules are an important tool both to understand biomolecular dynamics and interactions at nanoscale, and for medical diagnostics operating at their ultimate detection limits. Recently, exceptional sensitivity has been achieved using the strongly enhanced evanescent fields provided by optical microcavities and nano-sized plasmonic resonators. However, at high field intensities photodamage to the biological specimen becomes increasingly problematic. Here, we introduce an optical nanofibre based evanescent biosensor that operates at the fundamental precision limit introduced by quantisation of light. This allows a four order-of-magnitude reduction in optical intensity whilst maintaining state-of-the-art sensitivity. It enable quantum noise limited tracking of single biomolecules as small as 3.5 nm, and surface-molecule interactions to be monitored over extended periods. By achieving quantum noise limited precision, our approach provides a pathway towards quantum-enhanced single-molecule biosensors.Comment: 17 pages, 4 figures, supplementary informatio

    The role of attitude, control and intention to explain fruit and vegetable intake among racial/ethnic minority women with low socioeconomic status

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    OBJECTIVE: Fruit and Vegetable (FV) intake-a modi able risk factor for chronic diseases-is lower among racial/ethnic minorities and low Socio- Economic Status (SES) groups when compared to other populations. The Theory of Planned Behavior (TPB) is one theoretical model studied to explain and in uence individual health behaviors, including FV intake, in middle class populations, but not exclusively in diverse, low SES groups. This cross-sectional study evaluated the utility of select TPB variables to explain intention to consume and intake of FV in this population. DESIGN: Demographics, BMI, select TPB variables, and FV intake were measured via survey. Bivariate analyses were conducted to explore relationships between variables. Hierarchical regression analyses were used to t two models: one to explain intention and one to explain behavior with regard to FV vegetable intake. RESULTS: Participants (n=114) age 25-69 years and were mostly African American/Black and Hispanic (21.9% and 73%, respectively). The TPB variable perceived behavioral control was the only signi cant predictor of intention to consume FV (OR=2.55, 95% CI OR: 1.23, 5.27), and with BMI, FV intake (R2=0.08; F [2,130] =5.72, p=0.0042). CONCLUSION: Perceived behavioral control and BMI are the most signi cant predictors of FV intake but explain only 8% of the variability in intake in our cohort. Our results support prior research which suggests an attenuation of the intention-behavior relationship by SES, and may question the utility of the TPB as it is currently operationalized as a foundational model for future health behavior change research and programs in low SES racial/ethnic minorities

    Odd Association and Range Extension of Caligus rufimaculatus Wilson, 1905; Caligidae, Siphonostomatoida, Copepoda

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    The Caligidae (Siphonostomatoida, Copepoda) comprises more than 465 parasitic species, over 250 of which belong to Caligus Müller, 1785 (Boxshall and Halsey 2004). Caligus spp. are primarily marine; but some representatives routinely inhabit brackish or fresh water (Margolis et al. 1975). Some Caligus spp. have been widely reported from several oceans, others have been documented from a single location, and a few have only been collected as free-swimming individuals not associated with a host (Margolis et al. 1975). Caligus spp. range from being stenoxenous to euryxenous, with most species infecting actinopterygians (Actinopterygii), a much smaller group exclusively or non-exclusively infecting chondrichthyans (primarly elasmobranchs; Elasmobranchii, Chondrichthyes) (Margolis et al. 1975, Tang and Newbound 2004), and one species non-exclusively infecting an invertebrate (Ruangpan and Kabata 1984). Herein, we report a modest range extension for Caligus rufimaculatus Wilson, 1905 based on specimens collected in an odd association with a dead dolphin in the northern Gulf of Mexico (GOM) and we contribute new details regarding the morphology of the parasite

    Behavior of the Escape Rate Function in Hyperbolic Dynamical Systems

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    For a fixed initial reference measure, we study the dependence of the escape rate on the hole for a smooth or piecewise smooth hyperbolic map. First, we prove the existence and Holder continuity of the escape rate for systems with small holes admitting Young towers. Then we consider general holes for Anosov diffeomorphisms, without size or Markovian restrictions. We prove bounds on the upper and lower escape rates using the notion of pressure on the survivor set and show that a variational principle holds under generic conditions. However, we also show that the escape rate function forms a devil's staircase with jumps along sequences of regular holes and present examples to elucidate some of the difficulties involved in formulating a general theory.Comment: 21 pages. v2 differs from v1 only by additions to the acknowledgment

    Initial Data and Coordinates for Multiple Black Hole Systems

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    We present here an alternative approach to data setting for spacetimes with multiple moving black holes generalizing the Kerr-Schild form for rotating or non-rotating single black holes to multiple moving holes. Because this scheme preserves the Kerr-Schild form near the holes, it selects out the behaviour of null rays near the holes, may simplify horizon tracking, and may prove useful in computational applications. For computational evolution, a discussion of coordinates (lapse function and shift vector) is given which preserves some of the properties of the single-hole Kerr-Schild form

    Finite type approximations of Gibbs measures on sofic subshifts

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    Consider a H\"older continuous potential ϕ\phi defined on the full shift A^\nn, where AA is a finite alphabet. Let X\subset A^\nn be a specified sofic subshift. It is well-known that there is a unique Gibbs measure μϕ\mu_\phi on XX associated to ϕ\phi. Besides, there is a natural nested sequence of subshifts of finite type (Xm)(X_m) converging to the sofic subshift XX. To this sequence we can associate a sequence of Gibbs measures (μϕm)(\mu_{\phi}^m). In this paper, we prove that these measures weakly converge at exponential speed to μϕ\mu_\phi (in the classical distance metrizing weak topology). We also establish a strong mixing property (ensuring weak Bernoullicity) of μϕ\mu_\phi. Finally, we prove that the measure-theoretic entropy of μϕm\mu_\phi^m converges to the one of μϕ\mu_\phi exponentially fast. We indicate how to extend our results to more general subshifts and potentials. We stress that we use basic algebraic tools (contractive properties of iterated matrices) and symbolic dynamics.Comment: 18 pages, no figure
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