不同强度跑台运动对增龄大鼠血浆ET-1水平影响的研究     

李艳  王传世 《四川体育科学》2009,(2):32-34

为探讨不同强度跑台运动对老年机体内血浆内皮素-1（ET-1）水平的影响,以18月龄大鼠为研究对象,随机分为4组：大强度运动组、中等强度运动组、小强度运动组、增龄对照组,另设3月龄对照组．运动组的运动方式为跑台运动,共训练6周,观察增龄和不同强度跑台运动对大鼠血浆ET-1及血清MDA、SOD水平的影响。结果显示：增龄大鼠血浆ET-1、血清MDA水平与青年对照组相比显著升高,而血清SOD水平显著下降。经过为期6周的跑台运动,中等强度运动组增龄大鼠血浆ET-1、血清MDA水平显著下降,SOD活性显著增强,而强度过大或过小的运动训练则对其无显著性影响。  相似文献   

农业劳动力年龄对农户耕地利用效率的影响——来自不同经济发展水平地区的实证   总被引：9，自引：0，他引：9  

杨俊  杨钢桥  胡贤辉 《资源科学》2011,33(9):1691-1698

随着我国人口结构老龄化速度的加快,农业劳动力结构也呈现出老龄化趋势。本文分析了不同经济发展水平地区农业劳动力年龄对农户耕地利用效率所产生的影响。文中采用农户家庭主要农业劳动力年龄指标,并运用超越对数随机前沿生产函数对农户耕地利用效率进行了分析。分析结果表明我国农户耕地利用效率仅为71．63％,效率损失严重;农户劳动力年龄的增加对耕地利用效率的影响呈现倒“U”形趋势;以青壮年劳动力为主的农户耕地利用效率低于以老年劳动力为主的农户,需要制定激励政策提高其耕地利用效率;不同地区不同类型农户的劳动产出弹性、资本产出弹性、单位耕地劳动投入和资本投入不同,决定了不同类型农户耕地利用效率的区域差异。  相似文献   

Indices of novelty for emerging topic detection     

Yi-Ning Tu  Jia-Lang Seng 《Information processing & management》2012

Emerging topic detection is a vital research area for researchers and scholars interested in searching for and tracking new research trends and topics. The current methods of text mining and data mining used for this purpose focus only on the frequency of which subjects are mentioned, and ignore the novelty of the subject which is also critical, but beyond the scope of a frequency study. This work tackles this inadequacy to propose a new set of indices for emerging topic detection. They are the novelty index (NI) and the published volume index (PVI). This new set of indices is created based on time, volume, frequency and represents a resolution to provide a more precise set of prediction indices. They are then utilized to determine the detection point (DP) of new emerging topics. Following the detection point, the intersection decides the worth of a new topic. The algorithms presented in this paper can be used to decide the novelty and life span of an emerging topic in a specific field. The entire comprehensive collection of the ACM Digital Library is examined in the experiments. The application of the NI and PVI gives a promising indication of emerging topics in conferences and journals.  相似文献   

河南省人口现状特征分析     

吕可文  潘丛郁  徐晓霞 《安阳师范学院学报》2009,(2):97-101

人口问题始终是制约一个国家、区域全面、协调、可持续发展的重大问题。河南省作为中国第一人口大省,其在人口数量、规模、结构、索质等方面存在着突出问题,也面临前所未有的复杂形势。在综合分析河南省经济社会发展中人口现状的基础上,总结了河南省现阶段存在的人口特征及人口问题,为解决河南省人口问题和制定人口政策,促使河南省由人口大省转化为人口强省提供了基础和依据。  相似文献   

Expressions of cardiac sympathetic norepinephrine transporter and β1-adrenergic receptor decreased in aged rats     

He LI  Xiao-qing MA  Fan YE  Jing ZHANG  Xin ZHOU  Zhi-hong WANG  Yu-ming LI  Guo-yuan ZHANG 《Journal of Zhejiang University. Science. B》2009,10(3)

Evidence suggests that the deterioration of communication between the sympathetic nervous system and cardiovas-cular system always accompanies the aging of human and animals. Cardiac sympathetic norepinephrine (NE) transporter (NET) on presynaptic membrane is a predominant component to eliminate released NE in the synaptic cleff and maintains the sensitivity of the β-adrenergic receptor (β-AR). In the present study, we investigated NET and β1-AR mRNA levels and sympathetic nerve density in cardiac sympathetic ganglion and leff ventricular myocardium in 2- and 16-month-old rats with Northern blot analysis and immunohistochemistry. The expression levels of NET mRNA, NET protein and β1-AR mRNA in the ganglia or myocardia of 16-month-old rats were markedly reduced by 67%, 26%, and 43%, respectively, in comparison with those in 2-month-old rats. Our results also show that aging induces a strong decrease of the catecholaminergic nerve fiber density.  相似文献   

温州市图书馆的新实践——成立老年分馆     

吴蛟鹏 《图书馆杂志》2011,(9):42-44

以温州市图书馆为例,通过对老年分馆成立背景的分析和老年分馆成立后具体的服务和措施以及分馆成立后取得的效果的陈述,说明成立独立馆舍的老年分馆,是图书馆服务老年社会体系的重要途径。  相似文献   

The evaluation of selected poly(vinyl acetate) and acrylic adhesives: A final research update     

《文物保护研究》2013,58(1):33-54

Abstract

The final report on the Canadian Conservation Institute's poly(vinyl acetate) and acrylic adhesive research is given after 25–27 years of dark aging and 12–15 years of light aging. A total of 27 poly(vinyl acetate) and 25 acrylic adhesives were tested for pH, volatile emissions (mostly acetic acid), flexibility, strength, and yellowing after aging. In 1996, the work was first published after three to five years of aging data had accumulated. Measurements for pH, yellowing, strength, and flexibility were recently repeated again and these results are reported here. These new data points are reported to provide insight into the effect of these longer aging periods on the products included in the study. As well, the most stable (according to set criteria) poly(vinyl acetate) and acrylic adhesives tested are revealed, which, except for a few products, do not differ greatly from those reported in 1996.  相似文献   

Overlap among College and University Library Collections     

Debora Shaw 《资料收集管理》2013,38(3):117-132

Analysis of twenty-six college and university libraries' monographic holdings in WorldCat shows that university libraries hold radically more rare titles and their collections are seven times larger than college libraries. Language and Literature (Library of Congress [LC] class P) accounts for 30% of university and 27% of college holdings. The number of books held declines and the number owned by only one library increases after the 2000 publication year. Since then, total library budgets have barely kept pace with inflation and book budgets have declined as a percentage of library expenditures. These changes align with current emphasis on priorities other than book collections.  相似文献   

运动与女性衰老     

徐玉娥 《四川体育科学》2003,(4):23-24

本文从骨代谢、线粒体功能变化、糖的跨膜转运和心理调节几方面论述了体育运动对衰老女性的作用，认为体育运动可增强骨的形成和矿化、战少骨破坏、延缓骨量丢失，增强线粒体功能，提高机体免疫力，加速糖代谢，改善衰老女性的心理健康水平，以战少衰老女性的身心疾病，提高生活质量。  相似文献   

Circadian Time Structure of Circulating Plasma Lipid Components in Healthy Indians of Different Age Groups     

Ranjana Singh  Sumita Sharma  Raj K. Singh  Germaine Cornelissen 《Indian journal of clinical biochemistry : IJCB》2016,31(2):215-223

The circadian rhythm of human circulating lipid components was studied under nearnormal tropical conditions in 162 healthy volunteers (103 males and 59 females; 7 to 75 years of age). They followed a diurnal activity from about 06:00 to about 22:00 and nocturnal rest. These volunteers were divided into four groups: Group A (7–20 years), Group B (21–40 years), Group C (41–60 years) and Group D (61–75 years), comprising 42, 60, 35 and 25 participants, respectively. A marked circadian rhythm was demonstrated for each studied variable in each group by population-mean cosinor analysis (almost invariably p < 0.001). Furthermore, circadian rhythm characteristics were compared among the 4 groups by parameter tests and regressed as a function of age, separately for males and females. A second-order polynomial characterized the MESOR of HDL cholesterol, phospholipids and total lipids, as well as the 24-h amplitude of total cholesterol and phospholipids. The 24-h amplitude of total lipids decreased linearly with age. The 24-h acrophase of the oldest age group (Group D) was advanced in the case of total cholesterol, HDL cholesterol, and total lipids, whereas that of phospholipids was delayed. Mapping the circadian rhythm (an important component of the broader time structure or chronome, which includes a. o., trends with age and extra-circadian components) of lipid components is needed to explore their role in the aging process in health.  相似文献