Importance of Reproducibility in Responsiveness Issues

In cohort studies, longitudinal changes in individuals are often studied. The sample size requirements are then directly related to the responsiveness of the measuring instrument/scale, which is defined as the ability to detect a clinically meaningful change over time. We demonstrate that whatever the index used to assess responsiveness (effect size, standardized response mean, Guyatt's index), it is enhanced by an increase in the intraclass correlation coefficient (ICC), which assesses the reproducibility of the measuring instrument/scale. Therefore, an improvement in reproducibility leads to an increase in responsiveness and thus an increase in power. In the special case of one observation per subject and time, we also prove that an increase in the ICC reduces the coefficient of variation of the estimators of the standardized response mean and of Guyatt's index. This result has also been observed for the effect size on an example. Such a result implies that the better the reproducibility, the lower the sample size requirements for confident statistical inference of responsiveness results.     

新疆甘家湖梭梭林的光合、水分生理生态的研究

测定了梭梭林中梭梭柴等7个树种的光合和水分生理生态特性,包括其光合和呼吸强度、叶绿素含量、气孔状况、光合产物的分配及初级生产力、水分利用效率等,发现荒漠树种具有较高的光合效率和水分利用效率。6—9月梭梭柴的平均光合强度为8.02CO2mg／g,干重·h,它接近于中生树种新疆杨同期光合强度的平均值(8.39);白梭梭的蒸腾系数为250.12mg水／g干重,约是新疆杨蒸腾系数(502.45)的一半。荒漠树种的高光合和水分利用效率是它们长期适应高温干旱生态环境的结果。荒漠梭梭林通常仅作为薪炭林,这对光合产物的利用是很不经济合理的,需要改进。     

粤北石灰岩山地主要造林树种的生理生态学特性

本文是在调查粤北石灰岩山地植被的基础上,选出8种植物进行光能利用效率和蒸腾系数等生理生态学特性研究,并与非石灰岩山地较速生的荷木、藜蒴作比较,以筛选出适合石灰岩山地造林绿化的树种。结果表明,任豆、香椿与荷木、藜蒴的平均净光合速率(gCO2·m-2·d-1)分别为19.92,13.10,9.04和8.11;对光合有效辐射的利用效率(%)分别为4.21,4.59,2.71和2.52;蒸腾速率(gH2O·m-2·d-1)分别为2191,1266,1499和1133;蒸腾系数(gH2O·gDM-1)分别为164,144,244和209．说明任豆、香椿比荷木、藜蒴速生,光能利用效率、水分利用效率高,生态适应性强。光皮树、阴香的生长速度与荷木、藜蒴相似。菜豆树、桂花、铁榄、板栗的生长速度比荷木、藜蒴慢,但除板栗外都比较耐荫,对石灰岩山地环境也有较强的生态适应性。     

Comparative Studies on Relation of Photosynthesis to Water Status of Two Species of Haloxylon Under Controlled Environments

The net photosynthetic rate,transpiration rate and water content of assimilating shoots of Haloscyion ammodendron and H. persicum were measured under different radiation intensities, temperatures changes and different water status. Their water potential under different water status was also measured. The experimental results showed. (1) The dependence of photosynthetic rate and transpiration rate on radiation intensit in the two species of Haloscylon. The increase of net photosynthetic rate and transpiration rate of H. arnrnodendron depending on radiation intensity was lower than that of H. persicurn. Two species of Haloxylon also maintained high transpiration rate under dark. (2) The average transpiration rate of H. persicurn was lower than H. arnrnodendron,showing that H. persicurn utilized water more efficiently than H. arnrnodendron. (3)The optimal temperature of photosynthesis of H. arnrnodendron was 24–32℃ and the optimal temperature of water utilization of H. arnrnodendron was 23. 5–25℃. (4) The water potential of H. amrnodendron was lower than –3.5 MPa whereas that of H. persicum was lower than –2.8MPa indicating that the two species of Haloscylon were under severe water stress ,and would lead to permanent wilting of their assimilating shoots.     

柴达木盆地石炭纪古生物地理归属研究

柴达木盆地石炭纪的Ｔｉｎｇ类,珊瑚和腕足动物的代表属与中国其它代表地区－塔里木盆地,准噶尔盆地,陕甘宁地区,华北地区,华南地区,西藏北部地区可以进行对比,在计算大Ｚｏｎｇ相似系数的基础上,进行Ｑ型聚类分析,得出古生物地理分区结果,则解决柴达木盆地石炭纪古生物地理归属问题,研究结果表明,早石炭世可划分为：柴达木－华南－陕甘宁生物区;塔里木－藏北生物区和准噶尔生物区,柴达木属于柴达木－华南生物亚区,晚     

The Phytocommtunity and the Relations of the Element Contents Between Plants and Soils at Qing Chengzi Mining Area of Liaoning Province

The types of plant community and the floristic compositions in the leadzine abnormal and normal areas identified by geochemical exploration are basieally similar. According to the chemical analysis the contents of Pb, Zn, Cu, Cd of plants and soils in abnormal areas are higher than in normal areas. The absorption coeffieients of heavy metal elements by plants change with various chemical element, in the order of Cd>Zn, Cu>Pb. The results of the correlation analysis showed that the linear relationship between the contents of Pb, Zn in plant communities and in soil are singnifieant. There is a considerable linear correlation of Pb, Zn, Cu, Cd in soil and in Carex callitrichos, Sangnisorba officinalis, Polyoinum lopothitolium, Spirea pubescens, respectively. A close correlation presented in the contents of Pb, Zn, Cu, Cd between Carex callitrichos and soils. The multiple correlation coefficient is 0.999 (N=8, P<0.01). It may be suggested that Carex callitrichos can indicat the contents of Pb, Zn in soils.     

小良试验站三种景观类型地表径流效应的对比研究

基于连续10年的观测,本文对比研究了3种植被类型的地表径流效应,证明了混交林的水文效益无论从哪方面都较桉树林和裸地明显,并且随着年度的的推移,混交林的水文效益更加突出。发生产流的最小降雨量条件为：混交林30.2mm,桉树林5.1mm,裸地6.0mm。产流发生时饱和上层厚度分别为12.6mm,3.4mm,和6.3mm。理论上,作者阐明了3种植被类型下的产流类型,提出了桉树林下地表更易形成击实层这样一个设想,这就为水土保持林的营造提供了一个极富实际意义的例子,为在海岸台地这样一个特殊生境下综合研究水土保持效益提供了资料。     

Independent and joint action of cis- and trans-permethrin in Triatoma infestans (Hemiptera: Reduviidae)

The toxicity of pure cis- and trans-permethrin or mixtures of the two isomers topically applied to first, third, and fifth instar nymphs of Triatoma infestans (Klug) at 26°C was determined. The cis-isomer was more active than the trans-isomer in the three stages evaluated. When the two isomers were simultaneously applied to first instar nymphs, an additive effect was observed. Similar treatments of third and fifth instar nymphs resulted in an antagonistic effect. In third instar nymphs, the cis-isomer was more active than trans-isomer at all the three temperatures assayed (16°, 26°, and 36°C). The toxicity of the cis-isomer was lower at 36°C than at either 16° or 26°C. Temperature had no significant effect on the toxicity of the trans-isomer within the temperature range assayed. The toxicity of either isomer to third instar nymphs was not affected by pretreatment of nymphs with PBO (an inhibitor of mixed-function oxidases activity) or TPP (an inhibitor of esterase activity), suggesting that these detoxification pathways are not relevant in the metabolism of cis- or trans-isomers. Arch. Insect Biochem. Physiol. 37:225–230, 1998. © 1998 Wiley-Liss, Inc.