4,252 research outputs found

    How do baleen whales stow their filter? A compoarative bioimechanical analysis of baleen bending

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    Bowhead and right whale (balaenid) baleen filtering plates, longer in vertical dimension (3-4+ m) than the closed mouth, presumably bend during gape closure. This has not been observed in live whales, even with scrutiny of videorecorded feeding sequences. To determine what happens to baleen as gape closes, we conducted an integrative, multifactorial study including materials testing, functional (flow tank and kinematic) testing, and histological examination. We measured baleen bending properties along the dorsoventral length of plates and anteroposterior location within a rack of plates via mechanical (axial bending, composite flexure, compression, and tension) tests of hydrated and air-dried tissue samples from balaenid and other whale baleen. Balaenid baleen is remarkably strong yet pliable, with ductile fringes and low stiffness and high elasticity when wet; it likely bends in the closed mouth when not used for filtration. Calculation of flexural modulus from stress/strain experiments shows baleen is slightly more flexible where it emerges from the gums and at its ventral terminus, but kinematic analysis indicates plates bend evenly along their whole length. Fin and humpback whale baleen has similar material properties but less flexibility, with no dorsoventral variation. Internal horn tubes have greater external and hollow luminal diameter but lower density in lateral relative to medial baleen of bowhead and fin whales, suggesting greater capacity for lateral bending. Baleen bending has major consequences not only for feeding morphology and energetics but also conservation given that entanglement in fishing gear is a leading cause of whale mortality

    LCANets++: Robust Audio Classification using Multi-layer Neural Networks with Lateral Competition

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    Audio classification aims at recognizing audio signals, including speech commands or sound events. However, current audio classifiers are susceptible to perturbations and adversarial attacks. In addition, real-world audio classification tasks often suffer from limited labeled data. To help bridge these gaps, previous work developed neuro-inspired convolutional neural networks (CNNs) with sparse coding via the Locally Competitive Algorithm (LCA) in the first layer (i.e., LCANets) for computer vision. LCANets learn in a combination of supervised and unsupervised learning, reducing dependency on labeled samples. Motivated by the fact that auditory cortex is also sparse, we extend LCANets to audio recognition tasks and introduce LCANets++, which are CNNs that perform sparse coding in multiple layers via LCA. We demonstrate that LCANets++ are more robust than standard CNNs and LCANets against perturbations, e.g., background noise, as well as black-box and white-box attacks, e.g., evasion and fast gradient sign (FGSM) attacks.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Continued high rates of antibiotic prescribing to adults with respiratory tract infection: survey of 568 UK general practices

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    OBJECTIVES: Overutilisation of antibiotics may contribute to the emergence of antimicrobial drug resistance, a growing international concern. This study aimed to analyse the performance of UK general practices with respect to antibiotic prescribing for respiratory tract infections (RTIs) among young and middle-aged adults.SETTING: Data are reported for 568 UK general practices contributing to the Clinical Practice Research Datalink.PARTICIPANTS: Participants were adults aged 18-59?years. Consultations were identified for acute upper RTIs including colds, cough, otitis-media, rhino-sinusitis and sore throat.PRIMARY AND SECONDARY OUTCOME MEASURES: For each consultation, we identified whether an antibiotic was prescribed. The proportion of RTI consultations with antibiotics prescribed was estimated.RESULTS: There were 568 general practices analysed. The median general practice prescribed antibiotics at 54% of RTI consultations. At the highest prescribing 10% of practices, antibiotics were prescribed at 69% of RTI consultations. At the lowest prescribing 10% of practices, antibiotics were prescribed at 39% RTI consultations. The median practice prescribed antibiotics at 38% of consultations for 'colds and upper RTIs', 48% for 'cough and bronchitis', 60% for 'sore throat', 60% for 'otitis-media' and 91% for 'rhino-sinusitis'. The highest prescribing 10% of practices issued antibiotic prescriptions at 72% of consultations for 'colds', 67% for 'cough', 78% for 'sore throat', 90% for 'otitis-media' and 100% for 'rhino-sinusitis'.CONCLUSIONS: Most UK general practices prescribe antibiotics to young and middle-aged adults with respiratory infections at rates that are considerably in excess of what is clinically justified. This will fuel antibiotic resistance.<br/

    Characterization of microRNA expression in bovine adipose tissues: a potential regulatory mechanism of subcutaneous adipose tissue development

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    <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), a family of small non-coding RNA molecules, appear to regulate animal lipid metabolism and preadipocyte conversion to form lipid-assimilating adipocytes (<it>i.e. </it>adipogenesis). However, no miRNA to date has been reported to modulate adipogenesis and lipid deposition in beef cattle.</p> <p>Results</p> <p>The expression patterns of 89 miRNAs including four bovine specific miRNAs in subcutaneous adipose tissues from three groups of crossbred steers differing in backfat thickness were compared using qRT-PCR analysis. Eighty-six miRNAs were detectable in all samples, with 42 miRNAs differing among crossbreds (P < 0.05) and 15 miRNAs differentially expressed between tissues with high and low backfat thickness (P < 0.05). The expression levels of 18 miRNAs were correlated with backfat thickness (P < 0.05). The miRNA most differentially expressed and the most strongly associated with backfat thickness was miR-378, with a 1.99-fold increase in high backfat thickness tissues (r = 0.72).</p> <p>Conclusions</p> <p>MiRNA expression patterns differed significantly in response to host genetic components. Approximately 20% of the miRNAs in this study were identified as being correlated with backfat thickness. This result suggests that miRNAs may play a regulatory role in white adipose tissue development in beef animals.</p

    Anterolateral thigh osteomyocutaneous femur (ALTO) flap reconstruction for composite mandible and near total tongue defect utilizing a retrograde intramedullary femoral nail stabilization technique: Report of a first case

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    The anterior lateral thigh osteomyocutaneous free flap (ALTO) offers the advantage of reconstructing large bony and soft tissue defects. We report a novel approach for femur stabilization via retrograde intramedullary nail placement in a patient with a near total tongue and large mandibular defect who underwent ALTO reconstruction that saves operating room time and decreases risk of post-operative fracture

    Cigarette smoking increases the development of intimal hyperplasia after vascular injury

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    Purpose: Our purpose was to determine whether exposure to cigarette smoke increases the development of intimal hyperplasia (IH) after vascular injury.Methods: Sixteen adult male Sprague-Dawley rats underwent standardized balloon catheter injury of the left common carotid artery. For 4 weeks before and 4 weeks after injury, animals in the experimental group (n=8) were exposed to cigarette smoke with an automated vacuum pump device. Animals in the control group (n=8) were restrained in the smoking device for an identical amount of time and underwent arterial injury at 4 weeks but were not exposed to cigarette smoke. Carotid arteries were perfusion-fixed in vivo, prepared as histologic cross sections, and stained for elastin. IH was measured by planimetry and is reported both as the absolute area of IH and as the ratio (IH/IEL) of the absolute area of IH to the normalized area enclosed by the internal elastic lamina (expressed as a percent).Results: The absolute area of IH was 2.09±0.34 for the experimental group compared with 0.94±0.25 for the control group; mean IH/IEL was 43.7%±7.1% for the experimental group versus 17.7%±4.7% for the control group (p<0.05, two-tailed unpaired t test).Conclusions: Inhalation of cigarette smoke increases the development of intimal hyperplasia in a rat model of balloon catheter arterial injury
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