论创建高校和谐教育教学的微环境

文章通过对高等学校教育教学和谐观的意义、内涵的研究，提出了创建高等学校教育教学和谐微环境的方法。     

Assessment of the Effect of Population and Diary Sampling Methods on Estimation of School‐Age Children Exposure to Fine Particles

Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified‐random and random‐random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov‐chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM_2.5) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m³ for simulated children using the stratified population sampling method, and 12.2 μg/m³ using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m³ due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern.     

蛇胸腺基质细胞发育分化的超微结构研究

从超微结构方面对虎斑颈槽蛇（Ｒｈａｂｄｏｐｈｉｓｔｉｇｒｉｎａ）胚胎期间胸腺基质细胞的发育进行了观察分析．结果表明,胸腺上皮细胞在胚胎发育１１～１２期呈单一的淡染细胞类型,到１５期出现深染细胞类型,１６期胸腺皮质和髓质基本形成,胸腺上皮细胞也和成体的胸腺一样分化为被膜下上皮细胞、血管周上皮细胞、皮质上皮细胞和髓质上皮细胞．胸腺巨噬细胞和幼肌样细胞分别出现于胚胎发育１４期和１５期,随后细胞逐渐发育成熟,细胞数量增多;到胚胎发育１６期,它们分别分布于胸腺皮质和髓质．另外,在胚胎发育１４期,还可见到浆细胞样的细胞     

Humid microenvironment prerequisite for the survival and growth of nymphs of the rice brown planthopper,Nilaparvata lugens (St?l) (Homoptera: Delphacidae)

Nymphs ofNilaparvata lugens were experimentally reared from the 2nd instar in a cage covering part of the leaf sheath of an individual rice plant grown in a Wagner pot. Plants were covered with the cage from the water surface of the pot to 10 cm above the surface (lower cage-group) or from 10 cm to 20 cm above the surface (upper cage-group). Temperatures measured at three different parts of the cage remained fairly constant in both groups at around 25°C (23.7–25.2°C in mean value). In the lower cage-group, relative humidities measured at the three heights in the cage in (76.3–90.5% in mean value) markedly increased with the approach to the water surface. The nymphs of this group, particularly during the molting period, aggregated close to the surface. Eighty-two percent of the released nymphs emerged in this group. Relative humidities measured at three heights of the upper cage-group were 69.5–72.7% in mean value, and all the nymphs in this group died within 3 days after their release although half of them stayed on the rice plants within 6 h after their release. The role of relative humidity as a limiting factor on the range of the microhabitat and the population density ofN. lugens in rice fields was discussed on the basis of the results.