高数课程中内容扩展时的更新问题

在高等数学课程中,从平面解析几何扩展到空间解析几何,从一元微积分扩展到多元微积分时,既有量的直接扩展,又全面存在着质的变化,对许多概念、命题、方法需要重新审视,进行改造和更新。就高数课程中多元函数微积分教学的基本思路,笔者进行了一些分析、探讨。     

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30?h) at 60% maximal oxygen uptake ([Vdot]O_2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22?ml?·?kg^?1 body mass) in the first hour of the recovery interval (n = 8) and 500?ml just before exercise, followed by 250?ml every 20?min during exercise in the first (n = 9) and second exercise bouts (n = 9). Timed unstimulated saliva samples were collected at 10?min before exercise, after 48?–?50?min of exercise and during the last 2?min of exercise, at 1?h post exercise, 2?h post exercise (first exercise bout only), and 18?h post exercise (second exercise bout only). Venous blood samples were taken 5?min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2?h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90?min cycling at 60% [Vdot]O_2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.     

A Comparison of the English Vocabulary Used by Children of Non-American Ancestry in Hawaii before they Reach the Age of Seven Years with that of Kindergarten Children in Continental United States

The authors investigated 2 issues concerning the power of latent growth modeling (LGM) in detecting linear growth: the effect of the number of repeated measurements on LGM's power in detecting linear growth and the comparison between LGM and some other approaches in terms of power for detecting linear growth. A Monte Carlo simulation design was used, with 3 crossed factors (growth magnitude, number of repeated measurements, and sample size) and 1,000 replications within each cell condition. The major findings were as follows: For 3 repeated measurements, a substantial proportion of samples failed to converge in structural equation modeling; the number of repeated measurements did not show any effect on the statistical power of LGM in detecting linear growth; and the LGM approach outperformed both the dependent t test and repeated-measures analysis of variance (ANOVA) in terms of statistical power for detecting growth under the conditions of small growth magnitude and small to moderate sample size conditions. The multivariate repeated-measures ANOVA approach consistently underperformed the other tests.     

中国高新区重复开发的原因及其解决机制分析

地方政府对高新区产业的扶持和市场寻租行为导致了中国高新区低水平重复开发问题。如果市场发育,通过市场竞争机制和资源共享机制,中国高新区之间就可能避免技术开发过程中的盲目竞争和资源浪费,并形成正和博弈关系,产生真正的网络集聚效应。中国高新区在政府的支持下完成了早期的产业集聚之后,地方政府应逐渐减少对高新区特殊产业的扶持,将政府控制的创新资源转由市场配置给研发机构和研发人员。     

Use of the Counseling Center Assessment of Psychological Symptoms 62 (CCAPS-62) as a Repeated Measure

The purpose of this initial, exploratory study was to examine the utility of the Counseling Center Assessment of Psychological Symptoms-62 (CCAPS-62) as a repeated measure tool at one university counseling center. This study investigated whether clients engaged in individual counseling changed in symptomology while in treatment and when (e.g., session) changes in symptomology occurred. To answer these research questions, reliable change indexes (RCIs) were calculated for each subscale of the CCAPS-62. Results indicated that all eight of the CCAPS-62 subscales demonstrated reliable changes from initial to subsequent administrations, and that changes occurred between sessions 3 and 6 at this specific university counseling center. Findings suggest the importance of incorporating CCAPS-62 information into counseling sessions to inform treatment and assessment.     

《窦娥冤》:戏曲的剧场性与文本重复叙述策略

《窦娥冤》是元杂剧中的优秀剧作,从文学角度看,它也是一部优秀的文学作品。当剧本被作为文学作品阅读、分析和研究时,可以从戏剧的剧场性特点出发,对剧本中存在的重复叙事现象进行分析和理解,这样有助于对剧本文学的认识。     

医疗机构信息公开现状及对策研究

我国医疗机构信息公开的不足加剧了医患之间的信息不对称,这既造成了患者的盲目就医,又使得患者对医生约束乏力,从而在医患博弈中选择违规行为成了医生的占优战略。为了尽快消除信息公开不足所导致的不良后果,本文对医疗机构信息公开现状进行分析提出了相应的改革对策。     

穿过可液化土层的振动沉管灌注桩事故原因分析

通过对长江以南某市一银行办公综合楼穿过可液化粉砂土层的振动沉管灌注桩事故原因分析针对性地提出了若干值得注意的相关问题．     

重复采动浅析

介绍了重复采动对地面建筑物的危害，并介绍了重复采动的几种情况，提出了在垂深较小时，多煤层重复开采应加以经济对比，达到合理回收煤炭资源的目的。     

p^k元域上的方程∑α^ix^n-1-i=0与∑（-α）^ix^n-1-i=0

F是一个p^k元域．n是一个正整数．x^n-1 αxn^-2 … α^n-2 αn-1=0(α≠0)与x^n-1-αx^n-2 … (-α)^n-2x (-α)^n-1=0(α≠0)是F上的方程．本文完整地给出这些方程在F中的根的状况：(n，p^k-1)-1个单根．(n，p^k-1)组互不相同的重根，没有根．同时，给出根的求法及例子．