Effects of exercise on health-related quality of life and fear of falling in home-dwelling older women

This randomized, controlled trial evaluated the effects of exercise on health-related quality of life (HRQoL) and fear of falling (FoF) among 149 home-dwelling older women. The 12-mo exercise program was intended to reduce the risk of falls and fractures. HRQoL was assessed by the RAND-36 Survey, and FoF, with a visual analog scale, at baseline, 12 mo, and 24 mo. On all RAND-36 scales, the scores indicated better health and well-being. The exercise had hardly any effect on HRQoL; only the general health score improved slightly compared with controls at 12 mo (p = .019), but this gain was lost at 24 mo. FoF decreased in both groups during the intervention with no between-groups difference at 12 or 24 mo. In conclusion, despite beneficial physiological changes, the exercise intervention showed rather limited effects on HRQoL and FoF among relatively high-functioning older women. This modest result may be partly because of insufficient responsiveness of the assessment instruments used.     

A Bayesian model for cross-study differential gene expression

In this paper we define a hierarchical Bayesian model for microarray expression data collected from several studies and use it to identify genes that show differential expression between two conditions. Key features include shrinkage across both genes and studies, and flexible modeling that allows for interactions between platforms and the estimated effect, as well as concordant and discordant differential expression across studies. We evaluated the performance of our model in a comprehensive fashion, using both artificial data, and a "split-study" validation approach that provides an agnostic assessment of the model's behavior not only under the null hypothesis, but also under a realistic alternative. The simulation results from the artificial data demonstrate the advantages of the Bayesian model. The 1 - AUC values for the Bayesian model are roughly half of the corresponding values for a direct combination of t- and SAM-statistics. Furthermore, the simulations provide guidelines for when the Bayesian model is most likely to be useful. Most noticeably, in small studies the Bayesian model generally outperforms other methods when evaluated by AUC, FDR, and MDR across a range of simulation parameters, and this difference diminishes for larger sample sizes in the individual studies. The split-study validation illustrates appropriate shrinkage of the Bayesian model in the absence of platform-, sample-, and annotation-differences that otherwise complicate experimental data analyses. Finally, we fit our model to four breast cancer studies employing different technologies (cDNA and Affymetrix) to estimate differential expression in estrogen receptor positive tumors versus negative ones. Software and data for reproducing our analysis are publicly available.     

Son preference, use of maternal health care, and infant mortality in rural China, 1989-2000

This study assesses the effects of socio-economic conditions and the interaction between son preference and China's one-child family planning policy on the use of maternal health care services and their effects on infant mortality in rural China, using nationally representative data from the 2001 National Family Planning and Reproductive Health Survey. The results show that while the use of maternal health care services has continued to increase over time, large gaps still exist in the use of these services and in infant survival by mother's education, community income, and parity. Further improvements in the reproductive health of all women and in infant survival will require effective reduction of the obstacles to the use of maternal health care among those women in rural China who are less educated, poor, and of higher parity.     

Settlement size and fertility in the Nordic countries

While the variation in childbearing patterns across countries and between socio-economic groups within a country has been studied in detail, less is known about the differences in fertility patterns across settlements within a country. Using aggregate and individual-level register data, we examine fertility variation across settlements in Denmark, Finland, Norway, and Sweden. We observe a significant variation in fertility level by settlement size in all four of these Nordic countries - the larger the settlement, the lower the fertility. Second, the variation in fertility level has decreased over time, but significant differences in fertility between settlements of different size persist. Third, the timing of childbearing also varies across settlements - the larger the settlement, the later the peak of fertility. Fourth, our analysis of parity-specific fertility in Sweden shows that the major socio-economic characteristics of women account for only a small portion of fertility variation across settlements.     

Intergenerational Relationships and Union Stability in Fragile Families

Using data from the Fragile Families and Child Well being Study (N= 2,656), we examined the association between intergenerational relationships and parents' union stability five years after a baby's birth. Results showed that more amiable relationships between parents and each partner's parents, and more time children spent with paternal grandparents, were associated with increased odds that parents were co-residing by the time their focal child was age five. More time that children spent with maternal grandparents reduced union stability, although this result was not robust to methods that better address selection. These findings underscore the importance of the broader social contexts affecting couple stability. Findings further suggest that even amidst changing demographic conditions, intergenerational family ties are important for couples-and by extension-their children.     

俄罗斯农业:问题及前景

目前,居民的粮食保障是一个极为突出的社会问题。据估计,1991年全部农作物的收成低于上年。粮食生产规模缩小,经济合同规定上缴俄罗斯联邦的粮食数量未能兑现,这在一定程度上影响了粮食供应。除此之外,在实施向市场关系过渡的纲领时,俄罗斯政府大大减少了集体农庄和国营农场应向国家交纳粮食及其他产品的数量。根据俄罗斯第二次人民代表大会决议,农产品的粮食税不得超过以往时期年均生产     

二氮的有机化学

在过去的十年里,某些过渡金属体系与氮分子(即二氮)键合并使其活化的能力,对有机合成领域提供了一个新的途径,此种配位二氮或其质子化的衍生物与一些有机化合物(包括烷基和酰基卤化物,羧酸(酉午)、醛、酮和活化的芳基卤化物及乙烯基卤化物)反应,可直接形成碳——氮键。这个新途径就基于此种碳——氮键的形成。 早在六十年代后期,就出现了一些关于过渡金属促成二氮与有机化合物结合的报道〔1〕。但在那些研究中,很少涉及稳定的体系,而是在二氮和有机化合物的存在下,     

论全球学问题

80年代后期学者专家们对全球问题的兴趣明显低落了。这个现象引起人们的极大关注。究其原因,第一,人们逐渐感到全球问题不再是什么新鲜而非同寻常的问题,它已逐渐失去过去的那种神秘感和严重性。这是由于多年来一成不变地重复危险即将临头这类话语使人感到厌倦的结果;第二,不可逆转的危机即将来临,似乎天快塌下来了这类预言未能得到证实;第三,70年代中期制定出来的研究全人类问题的基本形式和基本方法导致得出若干过份危言耸听的结论;第四,为了有效地解决全