1,721,246 research outputs found
Clutton-Brock, T. — The Evolution of Parental Care. Princeton University Press, Princeton, Monographs in Behavior and Ecology, 8, 1991
No full textBourlière François. Clutton-Brock, T. — The Evolution of Parental Care. Princeton University Press, Princeton, Monographs in Behavior and Ecology, 8, 1991. In: Revue d'Écologie (La Terre et La Vie), tome 47, n°4, 1992. p. 435
Maternal deaths from anaesthesia. An extract from Why Mothers Die 2000-2002, the Confidential Enquiries into Maternal Deaths in the United Kingdom:Chapter 17: Trends in intensive care
No full textThis is the second of two extracts from Why Mothers Die 2000-2002, issued on 12 November 2004 by the Confidential enquiry into Maternal and Child Health (CEMACH), reproduced with permission. The full report can be accessed via their web site: http://www.cemach.org.uk/</p
Behavioural Models of Population Growth Rates:Implications for Conservation and Prediction
No full textConservation biologists often wish to predict how vertebrate populations will respond to local or global changes in conditions such as those resulting from sea–level rise, deforestation, exploitation, genetically modified crops, global warming, human disturbance or from conservation activities. Predicting the consequences of such changes almost always requires understanding the population growth rate and the density dependence. Traditional means of directly measuring density dependence are often extremely difficult and have the problem that if the environment changes then it is necessary to remeasure the density dependence. We describe an alternative approach that does not require such long datasets and can be used to predict the density dependence under novel conditions. Game theory can be used to describe behavioural decisions that individuals make in response to interference, prey depletion, territorial behaviour or social dominance, and the resultant fitness consequences. It is then possible to predict how survival or reproductive output changes with population size. From this we can then make predictions about the responses of populations to environmental changes. We will illustrate how this can be applied to a range of species and a range of applied problems
Near-infrared spectroscopy changes during hypothermic circulatory arrest with retrograde cerebral perfusion
No full textWe report on the changes in cerebral near-infrared spectroscopy during grafting of a thoraco-abdominal aneurysm. A 58-year-old man presented with a complex dissecting aortic aneurysm. Repair of the aneurysm was performed under hypothermic circulatory arrest with retrograde cerebral perfusion. Cerebral near-infrared spectroscopy monitoring revealed a reduction in the values recorded for total haemoglobin, oxygenated haemoglobin and cytochrome aa3 along with an increase in deoxygenated haemoglobin during circulatory arrest. When retrograde cerebral perfusion was commenced the signals representing total haemoglobin, oxygenated haemoglobin and cytochrome aa3 were all restored to near baseline values. Deoxygenated haemoglobin, however, remained elevated. These changes support the hypothesis that some cerebral perfusion occurs during retrograde cerebral perfusion.</p
In vitro performance of a new non-invasive extracorporeal saturation monitor
No full textA simulated cardiopulmonary bypass circuit was constructed in the laboratory to compare the accuracy and precision of a new non-invasive extracorporeal oxygen saturation monitor-- the M3 monitor (Spectrum Medical LLP, Gloucester, UK) against the Siemens RAPIDLab(®) blood gas analyser (Siemens AG, Munich, Germany). Comparisons were made across a range of oxygen saturations and at different temperatures and different haemoglobin concentrations. Results showed that under all conditions, when recording oxygen saturation, the M3 monitor achieved a mean (SD) bias of -0.9 (1.7)% with limits of clinical agreement of -4.2 to 2.5. However, the difference between the two monitors was larger at lower saturation levels (p < 0.001), lower haemoglobin levels (p = .002) and lower temperatures (p = 0.013). The mean (SD) haemoglobin concentration was 15.4 (0.6) when recorded by the M3 monitor, compared to 15.4 (0.5) g.dl(-1) measured by the blood gas analyser The M3 monitor compares favourably with the gold standard of the blood gas analyser and has the advantage of giving a continuous reading. You can respond to this article at http://www.anaesthesiacorrespondence.com.</p
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