2,178 research outputs found
Sound attenuation apparatus
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
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
The Svetitsky-Yaffe conjecture for the plaquette operator
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
Management of Acute Stroke in the Older Person.
The majority of people who suffer a stroke are older adults. The last two decades have brought major progress in the diagnosis and management of stroke, which has led to significant reductions in mortality, long-term disability, and the need for institutional care. However, acute, interventional and preventative treatments have mostly been trialled in younger age groups. In this article we will provide an overview of the evidence for acute stroke treatments in relation to age, discuss special considerations in the older person, and contemplate patient choice, quality of life, and end-of-life-decisions
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