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In 10 anesthetized dogs, we measured high-fidelity left circumflex coronary (P(LCx)), aortic (P(Ao)), and left ventricular (P(LV)) pressures and left circumflex velocity (U(LCx); Doppler) and used wave-intensity analysis (WIA) to identify the determinants of P(LCx) and U(LCx). Dogs were paced from the right atrium (control 1) or right ventricle by use of single (control 2) and then paired pacing to evaluate the effects of left ventricular contraction on P(LCx) and U(LCx). During left ventricular isovolumic contraction, P(LCx) exceeded P(Ao), paired pacing increasing the difference. Paired pacing increased DeltaP(X) (the P(LCx)-P(Ao) difference at the P(Ao)-P(LV) crossover) and average dP(LCx)/dt (P < 0.0001 for both). During this time, WIA identified a backward-going compression wave (BCW) that increased P(LCx) and decreased U(LCx); the BCW increased during paired pacing (P < 0.0001). After the aortic valve opened, the increase in P(Ao) caused a forward-going compression wave that, when it exceeded the BCW, caused U(LCx) to increase, despite P(LV) and (presumably) elastance continuing to increase. Thus WIA identifies the contributions of upstream (aortic) and downstream (microcirculatory) effects on P(LCx) and U(LCx).  相似文献   

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Contemporary psychotherapy is of integral nature. It is a part of integral medicine and of the integral viewpoint in science. Integrity is the opposite of polarity. There can be no doubt about it, sub-specialisation deepens the insight, simultaneously narrowing the efficiency of any activity. Integration is mandatory if we are to approach the victims of the Patriotic war in Croatia. Biological, psychological, social, philosophical and religious standpoints of an individual and a group of facilitators make the appropriate form of that approach. This is why education of facilitators has been directed towards integral way of thinking.  相似文献   

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In this article we introduce partial retraining, an algorithm to determine the relevance of the input variables of a trained neural network. We place this algorithm in the context of other approaches to relevance determination. Numerical experiments on both artificial and real-world problems show that partial retraining outperforms its competitors, which include methods based on constant substitution, analysis of weight magnitudes, and "optimal brain surgeon".  相似文献   

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Many analytical molecular genetic techniques developed over the past decade have evolved primarily to tackle the problem of targeting or isolating sequences of interest in complex mixtures. A new approach to this problem, Coincident Sequence Cloning (CSC), involves integrating a pair of DNA mixtures in such a way as to isolate any shared sequence components.  相似文献   

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The logic of expecting people who cannot stop smoking to switch to cigarettes that have hardly any nicotine is questionable. Tar and nicotine yields of cigarettes available in Britain today correlate 0-93, and further reduction of tar intake is limited by the reluctance of smokers to tolerate similar reductions in nicotine. A new approach would be to aim at lowering tar yields of cigarettes from the present average of 18 mg to around 6 mg but maintaining nicotine yields at around 1-0 to 1-2 mg, which would be acceptable to most smokers. This approach requires that emphasis be placed on tar: nicotine ratios as well as on the absolute yields. These ratios for brands on sale in Britain today average 14-2 and range from 9-6 to 20-8. They provide an additional guide for comparing the relative harmfulness of different brands. For example, 35% of cigarette smokers in Britain smoke either Embassy Filter or Players No 6 Filter; by changing to John Player Carlton King Size they could reduce their tar intake by more than 20% without having to suffer any nicotine deprivation.  相似文献   

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Hyoid bone is a part of viscerocranium placed between the tongue root and thyroid cartilage to which it is connected by thyrohyoid membrane. Widely accepted morphological classification does not exist. Sexual dimorphism was analysed in this study and new guidelines for anatomical classification of hyoid bones based on anthropometric parameters were given. Total number of analysed bones was 70. The bones were classified into three groups: symmetrical U-type, symmetrical V-type and asymmetrical type according to the angle between greater horns and the proportion of greater horns length. In the females incidence of asymmetrical type is considerably higher than in the males, while the incidence of symmetrical V-type is lower The angle value that is on average higher in males may be the parameter indicating that in puberty hyoid bone, still not completely ossified, to some extent follows development of thyroid cartilage because of their close anatomical relation.  相似文献   

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The immunocompetence handicap hypothesis proposes that testosterone mediates a trade-off between sexual signalling and immunocompetence in males. Such a trade-off could favour the reliability of sexual signals on the basis that testosterone required for signal expression also promotes immunosuppression. However, the immunosuppressive activity of testosterone has not been convincingly demonstrated. We propose that the optimal solution to the testosterone-mediated trade-off should change with age, explaining ambiguous results in the past. Testosterone and ageing would promote two simultaneous immunosuppressive challenges unaffordable for low-quality males. Oxidative stress, as intimately related to ageing and immunosenescence, could contribute to enhance signal reliability. In this context, traits coloured by carotenoids (yellow–red traits) could play a crucial role due to the immunostimulatory and antioxidant properties of these pigments. Here, old and middle-aged male red-legged partridges were treated with testosterone or manipulated as controls. In the presence of high-testosterone levels, middle-aged males increased both circulating carotenoid levels and colour expression, whereas their cell-mediated immunity was not significantly altered. However, in old males, neither circulating carotenoids nor sexual signalling increased when treated with testosterone, but immunosuppression was detected. The link between testosterone and carotenoids could favour the reliability of sexual signals throughout the life.  相似文献   

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We hypothesized that all-out running speeds for efforts lasting from a few seconds to several minutes could be accurately predicted from two measurements: the maximum respective speeds supported by the anaerobic and aerobic powers of the runner. To evaluate our hypothesis, we recruited seven competitive runners of different event specialties and tested them during treadmill and overground running on level surfaces. The maximum speed supported by anaerobic power was determined from the fastest speed that subjects could attain for a burst of eight steps (approximately 3 s or less). The maximum speed supported by aerobic power, or the velocity at maximal oxygen uptake, was determined from a progressive, discontinuous treadmill test to failure. All-out running speeds for trials of 3-240 s were measured during 10-13 constant-speed treadmill runs to failure and 4 track runs at specified distances. Measured values of the maximum speeds supported by anaerobic and aerobic power, in conjunction with an exponential constant, allowed us to predict the speeds of all-out treadmill trials to within an average of 2.5% (R2 = 0.94; n = 84) and track trials to within 3.4% (R2 = 0.86; n = 28). An algorithm using this exponent and only two of the all-out treadmill runs to predict the remaining treadmill trials was nearly as accurate (average = 3.7%; R2 = 0.93; n = 77). We conclude that our technique 1) provides accurate predictions of high-speed running performance in trained runners and 2) offers a performance assessment alternative to existing tests of anaerobic power and capacity.  相似文献   

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Disorders of the temporomandibular joint (TMJ), including TMJ osteoarthritis (TMJ OA), are the topic of intensive clinical research; however, this is not the case in the archaeological literature, with the majority of work on the subject ceasing with the early 1990s. The methods employed in the diagnosis of TMJ OA within the archaeological work appear nonrepresentative of the disease and may have led to erroneous assumptions about the pattern and prevalence of OA. This current work presents a new method for evaluating OA specifically for the TMJ, considering both the biomechanics of the joint and the mechanisms of the disease. Totally, 496 specimens (including a group of modern documented specimens) were analyzed for the presence of TMJ OA using the following criteria: eburnation, osteophytes (marginal and new bone on joint surface), porosity, and alteration to joint contour. The results suggest that eburnation occurs rarely in the TMJ, so should not be used as an exclusive criterion. Rather a combination of at least two of the other criteria should be used, with osteophytes and porosity occurring the most frequently on both the mandibular condyle and articular eminence. Additionally, the prevalence of TMJ OA in the modern assemblage was similar to that observed in current clinical research, suggesting that the method employed here was able to produce a reasonable approximation of what is found in contemporary living populations.  相似文献   

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