629 research outputs found
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A proposal to change the Office of Science injury reduction contractual performance measures
All ten of the Office of Science (SC) national laboratories have made significant progress in transforming the safety culture of their organizations over the last five to 10 years. The gradual downward trend in injury rates at each of these laboratories is evidence of this transformation. The present practice of inserting uniform injury-reduction metrics into each SC laboratory's contract, despite our differences, and attempting to measure that performance with limited sampling data, however, does not result in accurate assessments of performance. This paper offers an alternative approach to performance measurement
Embryonic Development of A Parthenogenetic Vertebrate, The Mourning Gecko (\u3cem\u3eLepidodactylus lugubris\u3c/em\u3e)
Background
One goal of evolutionary developmental biology is to understand the role of development in the origin of phenotypic novelty and convergent evolution. Geckos are an ideal system to study this topic, as they are speciesârich and exhibit a suite of diverse morphologiesâmany of which have independently evolved multiple times within geckos. Results
We characterized and discretized the embryonic development of Lepidodactylus lugubrisâan allâfemale, parthenogenetic gecko species. We also used softâtissue ÎŒCT to characterize the development of the brain and central nervous system, which is difficult to visualize using traditional microscopy techniques. Additionally, we sequenced and assembled a de novo transcriptome for a lateâstage embryo as a resource for generating future developmental tools. Herein, we describe the derived and conserved patterns of L. lugubris development in the context of squamate evolution and development. Conclusions
This embryonic staging series, ÎŒCT data, and transcriptome together serve as critical enabling resources to study morphological evolution and development, the evolution and development of parthenogenesis, and other questions concerning vertebrate evolution and development in an emerging gecko model
Colour scales with climate in North American ratsnakes: a test of the thermal melanism hypothesis using community science images
Animal colour is a complex trait shaped by multiple selection pressures that can vary across geography. The thermal melanism hypothesis predicts that darker coloration is beneficial to animals in colder regions because it allows for more rapid solar absorption. Here, we use community science images of three closely related species of North American ratsnakes (genus Pantherophis) to examine if climate predicts colour variation across range-wide scales. We predicted that darker individuals are found in colder regions and higher elevations, in accordance with the thermal melanism hypothesis. Using an unprecedented dataset of over 8000 images, we found strong support for temperature as a key predictor of darker colour, supporting thermal melanism. We also found that elevation and precipitation are predictive of colour, but the direction and magnitude of these effects were more variable across species. Our study is the first to quantify colour variation in Pantherophis ratsnakes, highlighting the value of community science images for studying range-wide colour variation
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Individuals With Scleroderma May Have Increased Risk of Sleep-Disordered Breathing.
STUDY OBJECTIVES:Scleroderma is associated with abnormal skin thickening, interstitial lung disease, pulmonary hypertension, and abnormalities of the upper airway. These changes can cause cardiopulmonary complications, potentially including sleep-disordered breathing. The objective of this study is to examine the risk of sleep-disordered breathing in patients with scleroderma. METHODS:We retrospectively identified patients with documented scleroderma. We abstracted data from their electronic health records, including findings from antibody tests, serial pulmonary function tests, transthoracic echocardiography, high-resolution computed tomography, and overnight forehead oximetry. RESULTS:We identified 171 patients with scleroderma. Mean age at the time of initial consult was 56.5 years (range, 18-96 years), and 150 (86.7%) were women. Scleroderma was categorized as limited disease for 108 (62.4%), diffuse disease for 59 (34.1%), and mixed connective tissue disease for 6 (3.5%). Fifty-four patients (31.2%) had abnormal overnight forehead oximetry results, defined as an oxygen desaturation index greater than 5 or a baseline mean arterial oxygen saturation level less than 90%. CONCLUSIONS:Cardiopulmonary complications are common in patients with scleroderma, one of which may be sleep-disordered breathing. In our cohort, approximately one-third of individuals with scleroderma had evidence of sleep-disordered breathing. Moreover, the rate of sleep-disordered breathing in our population of scleroderma patients was twice the rate of pulmonary hypertension and was approximately the same as the rate of interstitial lung disease. Future prospective studies are needed to further assess the role of sleep-disordered breathing in scleroderma clinical outcomes
A study of the effects of electric field on two-dimensional inviscid nonlinear free surface flows generated by moving disturbances
Two-dimensional free surface flows generated by a moving disturbance are considered. The flows are assumed to be potential. The effects of electric field, gravity and surface tension are included in the dynamic boundary condition. The disturbance is chosen to be a distribution of pressure moving at a constant velocity. Both linear and nonlinear results are presented. For some values of the parameters, the linear theory predicts unbounded displacements of the free surface. It is shown that this nonuniformity is removed by developing a weakly nonlinear theory. There are then solutions which are perturbations of a uniform stream and others which are perturbations of solitary waves with decaying tails
Diallel analysis of the combining ability of common bean (Phaseolus vulgaris L.) cultivars
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