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The effects of prolonged (5 x 45 min) reading in different environmental and ergonomic conditions on time-based glottal waveform parameters of normal female and male subjects (n = 80) were studied. The exposure groups (n = 5 females and males per cell) consisted of eight combinations of the following factors: (1) normal (< 65 dB) or high (> 65 dB) speech output level; (2) sitting or standing posture; (3) low (25 +/- 5%) or high (65 +/- 5%) relative humidity of ambient air. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustical signal using an automatic method. The following time based parameters were analyzed from the estimate glottal flow waveform: (1) length of fundamental period; (2) open quotient; (3) speed quotient, and (4) closing quotient. The analysis was based on inverse filtering of the first stressed syllable of 'paappa' word repeated 3 x 5 times with normal, maximally soft and maximally loud phonation. Humidity was a significant factor in several instances. The interactions between gender and the loading factors were striking.  相似文献   

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The effect of age, sex, season and cut variations on the protein, amino acids contents and protein efficiency ratio (P.E.R.) of Egyptian Buffalo meat was studied in 128 samples. Statistical analysis for the data obtained showed significant difference at 0.01 level for protein in relation to cut (abdomen and thigh, respectively), male in relation to season and dry season in relation to sex. There is also significant difference at 0.05 level in case of green season in relation to sex. Protein shows a significant difference at 0.1 level due to sex variation. There is a difference in the amino acids content of young and old animals during dry season in both cuts. Young animals show higher values than old ones in most of the amino acids investigated. There is also an obvious difference in the amino acids during green season between male and female animals, and also between both cuts. P.E.R. of Egyptian Buffalo meat as 10% protein level ranges between 3.02 and 2.35 according to seasonal, cut and age variations.  相似文献   

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Neuronal growth cones, the sensory-motile structures at the tips of developing axons, navigate to their targets over distances that can be many times greater than their diameter. They may accomplish this impressive task by following spatial gradients of axon guidance molecules in their environment (Bonhoeffer & Gierer, 1984; Tessier-Lavigne & Placzek, 1991; Baier & Bonhoeffer, 1994). We calculate the optimal shape of a gradient and the distance over which it can be detected by a growth cone for two competing mechanistic models of axon guidance. The results are surprisingly simple: Regardless of the mechanism, the maximum distance is about 1 cm. Since gradients and growth cones have coevolved, we suggest that the shape of the gradient in situ will predict the mechanism of gradient detection. In addition, we show that the experimentally determined dissociation constants for receptor-ligand complexes implicated in axon guidance are about optimal with respect to maximizing guidance distance. The relevance of these results to the retinotectal system is discussed.  相似文献   

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Regulation of coronary microvascular resistance is not distributed uniformly, but varies across different segments of the vasculature. Differences in regulatory mechanisms, including metabolic, myogenic, alpha-adrenergic and endothelial cell mediated, help define a series of coronary vascular microdomains. Generally, small arterioles, those less than 100 microns in diameter, respond differently than large arterioles or small arteries. This segmental distribution suggests an integrative hypothesis of regulation whereby a variety of mechanisms play a role in the overall response. One pathology that disturbs these control mechanisms in the microcirculation of the heart is reperfusion injury. Reperfusion injury of the microcirculation has as its primary target the vascular endothelium. The mechanisms responsible for reduced endothelium-dependent relaxation, likely include a reduction in the levels of tetrahydrobiopterin, a co-factor of nitric oxide synthase. Manipulation of levels of tetrahydrobiopterin in endothelial cells may be beneficial in the prevention of the pathophysiological sequelae of reperfusion injury in the coronary microcirculation.  相似文献   

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Psychotherapy for the handicapped might play an important role in helping these multiply stressed persons and their families. It can be put into practice much more easily than one may have presumed. It does not require any extreme specializations. Therefore, the gap between what is possible and the actual reality of a deep lack of efforts in this field calls for explanations, a part of which the author tries to outline.  相似文献   

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This review describes the ability of certain diseases, such as essential hypertension, atherosclerosis, angina, and vasospasm, to reduce vascular nitric oxide (NO) formation or to increase its metabolism. In contrast, others, such as hypotension, sepsis, stroke, myocardial depression, and inflammatory responses, increase NO synthesis. The mechanism implicated in the changes in the formation and metabolism of NO are described. To prevent or treat these pathological processes, in which a deficiency in vascular NO formation plays a causative role, NO may be provided through methods such as direct NO administration or indirect NO supply through either NO donors or L-arginine, which facilitates NO formation.  相似文献   

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为研究不同含水状态岩石的动态损伤特性,制备干燥、半饱和、饱和3种不同含水状态的砂岩试样.采用分离式霍普金森压杆(SHPB),以4种不同的低入射能对岩石进行损伤冲击试验.通过核磁共振测试实验对岩石试样进行孔隙扫描,获取岩石孔隙的T2谱曲线、孔隙度以及孔隙成像等数据.通过试验发现:(1)冲击能量的增加导致岩石的平均应变率和强度的增大;(2)不同含水状态的岩石受到冲击后,孔隙度与孔隙度变化率均有不同程度的增加;(3)与冲击前相比,岩石的T2谱曲线有明显右移趋势,同时出现谱峰增加的现象,而且冲击能量越大,孔隙谱峰增加越明显;(4)核磁共振成像显示岩石孔隙数量和尺寸有明显的增加,展现出岩石内部孔隙扩展和演化的过程.  相似文献   

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Four procedures for extinguishing anxiety were tested with rats as Ss. The results support the following conclusions: 1. Remaining away from an anxiety-eliciting situation for a short period of time does not bring about extinction of anxiety; 2. The Pavlovian extinction operation does weaken the strength of conditioned anxiety; 3. The anxiety extinction process is accelerated by the pairing, during the extinction operation, of the anxiety-producing stimulus with a positive reinforcer (a cage mate stimulus animal); and tentatively, 4. An additional emotionalizing operation (blocking of escape) that is concurrent with the extinction operation will impede the extinction process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Discusses some analytical and interactive computational applications of minicomputers in a laboratory of physiological psychology, using the PDP-11 and PDP-12 computers as examples. Applications considered range from instrumental conditioning of cats to training of ongoing EEGs in psychophysiology, and the physiological measures employed range from EMGs and heart rates to EEGs and single-cell and multiple neural units. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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A laboratory study was conducted about the duration of developmental stages and the productivity connected with the type of blood meal ingested by the female of Phlebotomus perniciosus. The pre-oviposition and egg incubation periods are not affected whatever the blood ingested by the female. The shorter time required to achieve larval development (rabbit) and pupal development (hamster) governs the generation time, shorter than in the other hosts (dog and man). The productivity is greater when blood is ingested from the rabbit and the dog. This is mainly due to the smaller number of eggs retained in females with these hosts.  相似文献   

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"The relationship between surface characteristics of Rorschach responses and physiological measures was investigated in order to test the hypothesis that the projected perception of one's body is related to the patterning of physiological responses… . Physiological indices related to bodily exterior (muscle potential, skin resistance, cardiovascular peripheral resistance) and bodily interior (pulse rate, stroke volume, cardiac output) physiological responsivity were abstracted… . The results indicate that the tendency to give impermeable or protective characteristics to Rorschach percepts is related to heightened physiological reactivity at an exterior body site and that the absence… is related to the heightened physiological response on interior indices… under stress." (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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