The birthrate drop in Iran

The recent steep decline in Iran's birthrate poses methodological and interpretive challenges insofar as statistical information on demographic factors cannot satisfactorily establish causalities or delineate processes of change. Our research suggests that this decline rests on the interplay of socio-cultural “idea” variables that augment factors of the developmental paradigm commonly used in population studies. Especially modernist ideas labeled “progress” in Iran have influenced reproductive behavior. Aiming to demonstrate the usefulness of idea-oriented qualitative research for understanding demographic dynamics represented quantitatively in the literature, we contribute to an explanation of a particular case as well as to demographic research methods.     

Allozyme variation of the endangered endemic plant Myricaria laxiflora: Implications for conservation

Myricaria laxiflora, a riparian plant that naturally occurs in the riverbanks of the Yangtze River Valley, has become extinct across its entire geographical distribution range in the wild due to the construction of the Three Gorges Dam. The allozyme variation of M. laxiflora populations was investigated in the present study. Mean number of alleles per locus (A) was 2.35, and the observed heterozygosity (H_o) and expected heterozygosity (H_e) were 0.35 and 0.30, respectively. Six populations showed significant excesses of heterozygotes based on the examination of a multilocus fixation index (F_IS). The population genetic divergence of M. laxiflora is high (G_ST = 0.144 and ?_B = 0.131) and the analysis of molecular variance analysis shows that 19.71% of the total genetic variation is caused by the difference between populations. Based on the obtained genetic information, six management units have been identified, all of which are expected to enhance the effective management of the remaining and transplanted individuals of this endangered species in the future.     

The Impacts of Household Consumption and Options for Change

This introductory article situates the contributions that comprise this special issue within the field of sustainable consumption and production (SCP) studies. After a brief review of the policy history surrounding SCP, we organize our discussion and the subsequent collection of articles into two groups. The first suite of articles views the environmental impacts associated with household consumption from the perspectives of different consumer groups, income levels, and geographic areas. This work confirms and refines several insights that have been developing over the past several years, namely that food and beverages, mobility, housing, and energy-using products are the most critical consumption domains from the standpoint of environmental sustainability and that higher household income leads to greater (but less than proportional) impacts. The second subset of articles analyzes the potential for mitigating these impacts through behavioral changes and innovation strategies. Although the contributions to this special issue describe several noteworthy examples of information- and team-based initiatives to catalyze behavioral changes, the state of knowledge pertaining to this aspect of the consumption problem is much more inchoate. Research on the formulation and implementation of effective "change management for sustainable consumption" should be treated as an area of priority attention for industrial ecologists.     

癔症发作诱发因素以及复发几率分析

目的:探讨导致癔症发病病因和复发几率之间的联系,以便为研究、预防和治疗癔症工作提供科学依据。方法:以近30年国内外有关癔症危险因素的研究成果为基础,对符合CCMD-3诊断标准的100例癔症患者进行回顾性分析及前瞻性观察。结果:癔症相关的危险因素比较多,患者多内向,神经质影响心理症状最大,情绪明显不稳定;他们的父母较正常人的父母对子女缺乏情感温暖,并有过度的拒绝和过度保护,家庭不和睦,其在发病前一年内负性生活事件数目与严重程度均高于一般人;情绪表达受限,生活单调乏味,父母采取不良教养方式,人际关系紧张等。且患者性格因素引起的癔症复发几率较高,而因负性生活事件的原因复发几率在几种情况中最低。结论:癔症病因主要有人格特征,家庭环境,生活事件,教养方式,人际关系等,正确教育方式和朋友良好的关系,以及和谐的家庭及社会环境,及时治疗相关的并发症,可明显减少发病和复发概率。     

超氧化物岐化酶在医学领域的研究现状

超氧化物歧化酶(SOD)是生物体内清除超氧阴离子自由基(O2-.)的一种重要金属酶,具有重要的生理功能,在医药、食品等方面有广泛的应用前景,是目前医学、分子生物学领域研究的热点之一。现对SOD的分类、分布、结构、性质、在相关疾病中的研究进展、临床应用等方面做一综述。     

Effects of molybdate,sulfide, and tetrathiomolybdate on copper metabolism in rats

Species differences in the response to dietary MoO₄^2? as a metabolic antagonist of Cu are considered briefly. Suggestions that (i) the potency of MoO₄^2? as a Cu antagonist is enhanced by normally innocuous dietary concentrations of S^2? and (ii) that MoS₄^2? may be a more effective antagonist than either MoO₄^2? or S^2? were investigated in a series of studies with rats. Diets including MoS₄^2? but not of MoO₄^2? or S^2? alone promoted a decline in hepatic Cu and ceruloplasmin activity and induced clinical signs of Cu deficiency. Evidence of concurrent anomalies in the partition of Cu between tissues and in the distribution of Cu between proteins of plasma and kidney cytosol suggested that such effects were partly attributable to the development of systemic defects in Cu metabolism. The relationship of such findings to the suggested involvement of MoS₄^2? or its derivatives in the etiology of Mo-induced Cu deficiency in ruminant animals is considered.     

Genetic polymorphism of glutamine synthetase and delta-9 desaturase in families of Pacific oyster Crassostrea gigas and susceptibility to summer mortality

Large-scale mortality events have been observed in Pacific oyster Crassostrea gigas on the west coast of France since the early 1980s, particularly during summer. In order to understand the causes of this mortality, two generations of oysters from single-pair matings were studied in three sites on the French Atlantic coast (Baie-des-Veys, Auray and Ronce-les-Bains). The present paper examines the role of two candidate genes in the susceptibility of oysters to summer mortality, and the selective pressure exerted by such mortality on their polymorphism. Glutamine synthetase (amino-acid metabolism) and delta-9 desaturase (lipid metabolism) genes were studied in the successive generations, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP). Observed and expected genotypic frequencies were compared. Three different alleles were detected for the glutamine synthetase gene and two for delta-9 desaturase. Allele C of glutamine synthetase seemed to be counter-selected in some second generation families. Allele B of delta-9 desaturase gene was potentially counter-selected at Auray in the families showing higher mortality, and strong selection against BB homozygotes was observed. These observations led us to conclude that any selective effect of summer mortality on allele C of glutamine synthetase gene or allele B of delta-9 desaturase gene could be mediated either directly or via linkage to other loci involved in physiological pathways affecting susceptibility.     

Ranking Alaska Moose Nutrition: Signals to Begin Liberal Antlerless Harvests

Abstract: We focused on describing low nutritional status in an increasing moose (Alces alces gigas) population with reduced predation in Game Management Unit (GMU) 20A near Fairbanks, Alaska, USA. A skeptical public disallowed liberal antlerless harvests of this moose population until we provided convincing data on low nutritional status. We ranked nutritional status in 15 Alaska moose populations (in boreal forests and coastal tundra) based on multiyear twinning rates. Data on age-of-first-reproduction and parturition rates provided a ranking consistent with twinning rates in the 6 areas where comparative data were available. Also, short-yearling mass provided a ranking consistent with twinning rates in 5 of the 6 areas where data were available. Data from 5 areas implied an inverse relationship between twinning rate and browse removal rate. Only in GMU 20A did nutritional indices reach low levels where justification for halting population growth was apparent, which supports prior findings that nutrition is a minor factor limiting most Alaska moose populations compared to predation. With predator reductions, the GMU 20A moose population increased from 1976 until liberal antlerless harvests in 2004. During 1997-2005, GMU 20A moose exhibited the lowest nutritional status reported to date for wild, noninsular, North American populations, including 1) delayed reproduction until moose reached 36 months of age and the lowest parturition rate among 36-month-old moose (29%, n = 147); 2) the lowest average multiyear twinning rates from late-May aerial surveys (x = 7%, SE = 0.9%, n = 9 yr, range = 3-10%) and delayed twinning until moose reached 60 months of age; 3) the lowest average mass of female short-yearlings in Alaska (x̄ = 155 ± 1.6 [SE] kg in the Tanana Flats subpopulation, up to 58 kg below average masses found elsewhere); and 4) high removal (42%) of current annual browse biomass compared to 9-26% elsewhere in boreal forests. When average multiyear twinning rates in GMU 20A (sampled during 1960-2005) declined to <10% in the mid- to late 1990s, we began encouraging liberal antlerless harvests, but only conservative annual harvests of 61-76 antlerless moose were achieved during 1996-2001. Using data in the context of our broader ranking system, we convinced skeptical citizen advisory committees to allow liberal antlerless harvests of 600-690 moose in 2004 and 2005, with the objective of halting population growth of the 16,000-17,000 moose; total harvests were 7-8% of total prehunt numbers. The resulting liberal antlerless harvests served to protect the moose population's health and habitat and to fulfill a mandate for elevated yield. Liberal antlerless harvests appear justified to halt population growth when multiyear twinning rates average ≤10% and ≥1 of the following signals substantiate low nutritional status: <50% of 36-month-old moose are parturient, average multiyear short-yearling mass is <175 kg, or >35% of annual browse biomass is removed by moose.     

植物铝离子胁迫的研究方法综述

酸性土壤上,植物的生长受到很大的抑制,铝对植物的毒害是最主要的问题。为了揭示植物铝离子胁迫反应及其耐铝性的机理,科学家们进行了大量研究,取得了许多喜人的进展。根据前人研究,对植物铝离子胁迫的研究方法进行了综述。在试验材料的处理方面介绍了大田栽培、室外盆栽、室内盆栽、营养液栽培等方法;在耐铝性鉴定方面介绍了受害症状、根相对伸长率等直接鉴定法和化学染色、有机酸分泌量等间接鉴定法;在铝离子胁迫基因研究方面,介绍了基因定位技术、基因差异表达研究技术、蛋白质差异表达研究技术及转基因技术等研究方法。     

PCR-SSCP技术的研究及应用进展

阐述了SSCP技术的建立与发展过程;概述了PCR-SSCP技术的原理、方法、优缺点及突变技术研究进展;总结了PCR-SSCP技术在多个领域中(动物育种、基因突变、基因诊断、基因图谱和连锁分析等)的应用情况;分析了PCR-SSCP技术在分子生物学研究领域中的作用。