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61.
CH Brenner 《Canadian Metallurgical Quarterly》1998,62(6):1558-60; author reply 1560-1
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Administered a digit symbol and a motor manipulation task to 20 premedical, 15 premedical dropout, and 20 liberal art undergraduate students. Ss were led to believe they were competing against another student like themselves. However, the 2nd member of each pair was actually a confederate of e, making it possible to experimentally manipulate success and failure. There were no performance differences among the groups on the initial trial of each of the 2 tasks. Under competitive conditions, however, improvement in performance was significantly greater for premedical ss than for premedical dropouts, and greater for these latter ss than for the liberal arts ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Berndt David J.; Schwartz Steven; Kaiser Charles F. 《Canadian Metallurgical Quarterly》1983,51(4):627
Reading grade levels were obtained for 10 depression scales (e.g., Beck Depression Inventory) using 2 empirically based readability formulae, one by R. Gunning (1952) and the other by R. F. Flesch (1949). Results suggest that most of the scales are appropriate for use with both adolescents and adult patients who have attained 9th-grade-level reading skills. The limitations of empirical estimates of readability are discussed, and it is noted that comprehension could be influenced by contextual variables such as scale format. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
Micropuncture studies were performed in 33 Munich-Wistar rats maintained chronically either on dietary NaCl restriction (group 1) or excess (group 2). Values for single nephron (SN) and total kidney glomerular filtration rate (GFR) were identical in both groups. Nevertheless, because of preferential efferent vasoconstriction, glomerular capillary hydraulic pressure (PGC) was higher in group 1, offsetting the lower initial glomerular plasma flow rate (QA) also found in group 1. The pressor response to infusion of exogenous angiotensin II (AII) was less in group 1 than in group 2, suggesting that vascular receptors for AII may have been occupied by endogenous hormone, the latter leading to the efferent arteriolar vasoconstriction. In addition to AII, prostaglandins also appear to be involved in the adaptations of the glomerular microcirculation to chronic variations in salt intake. In group 1, indomethacin or meclofenamate infusion mimicked exogenous AII, causing declines in QA and SNGFR. These changes were lacking in group 2. Because of relative contraction of plasma volume, the vasodilatory effects of prostaglandins appear to be needed in low salt animals to sustain SNGFR and QA. In the high salt group, however, since plasma volume is not contracted, maintenance of SNGFR and QA appears to be less critically dependent on endogenous prostaglandins. 相似文献
67.
A study was made of the diurnal changes in liver microsomal desaturation of labeled stearic, linoleic and α-linolenic acids
to oleic, γ-linolenic and octadeca-6,9,12,15-tetraenoic acids, respectively. C3H-S mice were used and were exposed to light-dark
cycles. A circadian rhythm was observed for stearic acid desaturation, and a different one for linoleic acid. Linoleic and
α-linolenic desaturation had similar responses in the day cycle. This would indicate that different mechanisms control the
oxidative desaturations of the fatty acids in the 9 and 6 carbons. The fatty acid composition of the whole liver and liver
microsomes also showed variations. Remarkable oscillations were observed for stearic and oleic acids. Neither the total protein
synthesis nor the free fatty acid concentration in the microsomes followed a rhythm parallel to the desaturation of the studied
fatty acids. The injection of cycloheximide 4 hr before measuring the desaturation modified the circadian variation of both
the 9 and 6 desaturations. The modification induced by cycloheximide was considered to indicate that both variations are related
to the synthesis of specific proteins but not to that of a degradative or inhibitory protein. 相似文献
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M.L. Berndt 《Construction and Building Materials》2011,25(10):3893-3902
Deterioration of concrete in cooling tower basins by microbiologically influenced corrosion (MIC) is a concern in geothermal power plants. The effect of supplementary cementitious materials, epoxy coatings, latex-modified mortars and calcium aluminate cement mortar for protecting concrete from MIC was investigated. Laboratory exposure tests to a particular type of sulphur and iron oxidising bacteria, Thiobacillus ferrooxidans, were performed to rank candidate materials and these were followed by field exposure tests of the best materials in a cooling tower basin. It was determined that partial replacement of cement with 40% blast furnace slag or 5% to 10% silica fume improved resistance to MIC. A replacement level of 60% slag resulted in similar performance to concrete made with ordinary Portland or sulphate resistant cement. Epoxy- and styrene butadiene latex-modified mortars offered protection to concrete but still underwent a degree of attack. Epoxy coatings were found to be effective in protecting concrete. Calcium aluminate cement mortar showed excellent durability in laboratory and field tests. 相似文献