2,622 research outputs found

    Evolutionary stasis and lability in thermal physiology in a group of tropical lizards

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    Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation, or both. Here we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming

    Application of Ultrasonic Pod Models

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    The ability to quantify the reliability of nondestructive evaluation (NDE) inspection techniques is required to integrate inspectability into the component design process. Inspectability is typically evaluated on the basis of the design engineer’s experience and knowledge of NDE. While this approach can yield adequate designs with regard to inspection reliability, the potential for uninspectability remains. There is also the possibility that the designer’s knowledge of the reliability of NDE techniques may be limited to “standard” approaches which may be be inadequate for new component geometries or materials. This could lead the design engineer to imagine that a given component is inadequately inspectable and to redesign the part when the correct solution is either to modify the inspection protocol or to select a different technique. Alternatively, models which predict inspection reliability could be used to weigh the trade-offs and risks associated with selection among candidate NDE techniques to be applied to inspection of a given component design and to identify NDE system configurations for optimal reliability. This approach is, in fact, a key feature of the Unified Life Cycle Engineering concept currently being developed by the Air Force[l]

    Logarithmic asymptotics of the densities of SPDEs driven by spatially correlated noise

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    We consider the family of stochastic partial differential equations indexed by a parameter \eps\in(0,1], \begin{equation*} Lu^{\eps}(t,x) = \eps\sigma(u^\eps(t,x))\dot{F}(t,x)+b(u^\eps(t,x)), \end{equation*} (t,x)\in(0,T]\times\Rd with suitable initial conditions. In this equation, LL is a second-order partial differential operator with constant coefficients, σ\sigma and bb are smooth functions and F˙\dot{F} is a Gaussian noise, white in time and with a stationary correlation in space. Let p^\eps_{t,x} denote the density of the law of u^\eps(t,x) at a fixed point (t,x)\in(0,T]\times\Rd. We study the existence of \lim_{\eps\downarrow 0} \eps^2\log p^\eps_{t,x}(y) for a fixed yRy\in\R. The results apply to a class of stochastic wave equations with d{1,2,3}d\in\{1,2,3\} and to a class of stochastic heat equations with d1d\ge1.Comment: 39 pages. Will be published in the book " Stochastic Analysis and Applications 2014. A volume in honour of Terry Lyons". Springer Verla

    Evaluation of the London Measure of Unplanned Pregnancy in a United States population of women

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    Copyright @ 2012 Morof et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objective: To evaluate the reliability and validity of the London Measure of Unplanned Pregnancy (a U.K.-developed measure of pregnancy intention), in English and Spanish translation, in a U.S. population of women. Methods: A psychometric evaluation study of the London Measure of Unplanned Pregnancy (LMUP), a six-item, self-completion paper measure was conducted with 346 women aged 15–45 who presented to San Francisco General Hospital for termination of pregnancy or antenatal care. Analyses of the two language versions were carried out separately. Reliability (internal consistency) was assessed using Cronbach’s alpha and item-total correlations. Test-retest reliability (stability) was assessed using weighted Kappa. Construct validity was assessed using principal components analysis and hypothesis testing. Results: Psychometric testing demonstrated that the LMUP was reliable and valid in both U.S. English (alpha = 0.78, all item-total correlations .0.20, weighted Kappa = 0.72, unidimensionality confirmed, hypotheses met) and Spanish translation (alpha = 0.84, all item-total correlations .0.20, weighted Kappa = 0.77, unidimensionality confirmed, hypotheses met). Conclusion: The LMUP was reliable and valid in U.S. English and Spanish translation and therefore may now be used with U.S. women.The study was funded by an anonymous donation

    Methyl iodide poisoning presenting as a mimic of acute stroke: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Stroke mimics are usually non-vascular disease processes. These raise the possibility of a stroke and are common in clinical practice. It is necessary to distinguish these mimics in order to provide early and appropriate management, as well as reduce possible harm on our patient.</p> <p>Case presentation</p> <p>We report the case of a 50-year-old Caucasian man who developed symptoms suggestive of posterior circulation stroke after he was exposed to methyl iodide at his workplace. Results of stroke investigations of our patient were negative, and a detailed occupational history clinched the diagnosis. Acute presentation with a stroke-like picture is rare in cases of methyl iodide poisoning. We have attempted to discuss the differential diagnosis of stroke mimics through a review of literature.</p> <p>Conclusion</p> <p>Stroke mimics are difficult to diagnose in an emergency room situation and may be initially treated as stroke. This case report underlines the importance of history taking, especially occupational history, in the differential diagnosis of stroke. We also stress the need to recognize mimics at presentation in order to arrive at an early and appropriate management of patients.</p
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