2,165 research outputs found

    Sound attenuation apparatus

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    An apparatus is disclosed for reducing acoustic transmission from mechanical or acoustic sources by means of a double wall partition, within which an acoustic pressure field is generated by at least one secondary acoustic source. The secondary acoustic source is advantageously placed within the partition, around its edges, or it may be an integral part of a wall of the partition

    Hypoxia after stroke: a review of experimental and clinical evidence

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    Background Hypoxia is a common occurrence following stroke and associated with poor clinical and functional outcomes. Normal oxygen physiology is a finely controlled mechanism from the oxygenation of haemoglobin in the pulmonary capillaries to its dissociation and delivery in the tissues. In no organ is this process more important than the brain, which has a number of vascular adaptions to be able to cope with a certain threshold of hypoxia, beyond which further disruption of oxygen delivery potentially leads to devastating consequences. Hypoxia following stroke is common and is often attributed to pneumonia, aspiration and respiratory muscle dysfunction, with sleep apnoea syndromes, pulmonary embolism and cardiac failure being less common but important treatable causes. As well as treating the underlying cause, oxygen therapy is a vital element to correcting hypoxia, but excessive use can itself cause molecular and clinical harm. As cerebral vascular occlusion completely obliterates oxygen delivery to its target tissue, the use of supplemental oxygen, even when not hypoxic, would seem a reasonable solution to try and correct this deficit, but to date randomised clinical trials have not shown benefit. Conclusion Whilst evidence for the use of supplemental oxygen therapy is currently lacking, it is vital to rapidly identify and treat all causes of hypoxia in the acute stroke patient, as a failure to will lead to poorer clinical outcomes. The full results of a large randomised trial looking at the use of supplemental oxygen therapy are currently pending

    Section 346 of the Internal Revenue Code: A Legislative Enigma

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    The Svetitsky-Yaffe conjecture for the plaquette operator

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    According to the Svetitsky-Yaffe conjecture, a (d+1)-dimensional pure gauge theory undergoing a continuous deconfinement transition is in the same universality class as a d-dimensional statistical model with order parameter taking values in the center of the gauge group. We show that the plaquette operator of the gauge theory is mapped into the energy operator of the statistical model. For d=2, this identification allows us to use conformal field theory techniques to evaluate exactly the correlation functions of the plaquette operator at the critical point. In particular, we can evaluate exactly the plaquette expectation value in presence of static sources, which gives some new insight in the structure of the color flux tube in mesons and baryons.Comment: 8 pages, LaTeX file + three .eps figure

    On the Gini–Simpson index and its generalisation—A historic note

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