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991.
Darwin's Fox: A Distinct Endangered Species in a Vanishing Habitat   总被引:2,自引:0,他引:2  
The temperate rain forest of Chiloé Island, Chile, is inhabited by an endemic fox ( Dusicyon fulvipes ) first described by Charles Darwin and now designated Darwin's fox. Despite morphological differences, Darwin's fox has been considered only an insular subspecies of the mainland chilla fox ( D. griseus ). This follows the assumption that the island population, with an estimated population of less than 500, has been separated from the mainland chilla fox for only about 15,000 years and may have received occasional immigrants from the mainland. Consequently, this island population has not been protected as endangered or bred in captivity. Recently, a population of Darwin's fox was discovered on the Chilean mainland 600 km north of Chiloé Island. This population exists in sympatry with chilla and possibly culpeo ( D. culpaeus ) foxes, which suggests that Darwin's fox may be reproductively isolated. To clarify the phylogenetic position of Darwin's fox, we analyzed 344 bp of mitochondrial DNA control-region sequence of the three species of Chilean foxes. Darwin's foxes from the island and mainland populations compose a monophyletic group distinct from the two other Chilean fox species. This indicates that Darwin's fox was probably an early inhabitant of central Chile, and that its present distribution on the mainland may be a relict of a once much wider distribution. Our results highlight the ability of molecular genetic techniques to uncover historical relationships masked by recent events, such as local extinctions. The "rediscovery" of Darwin's fox as a distinct species implies that greater significance should be given to the protection of this species and its unique habitat and to documenting the extent of its mainland distribution.  相似文献   
992.
从摇篮到摇篮设计是一种建筑学的生态智能设计理念,它涉及到完全健康的、可恢复的居住区的材料、建筑物和模式的相关产业.与从摇篮到坟墓体系不同,从摇篮到摇篮设计把人类系统看作是营养循环系统,其中的每一种物质都能够支撑生命.作为生物养分设计的材料在使用后为大自然提供了营养物;通过生产-恢复-再造的产业闭路系统技术养分得以循环.依据选择安全、健康因素的科学建议,从摇篮到摇篮设计把对材料的利用发挥到了极致.本着对自然、文化、气候负责的精神,在工业化国家和发展中国家,它推出的建筑物与社区规划都创造了多种多样的经济、社会和生态价值.  相似文献   
993.
Using data collected from residents surrounding a large urban park setting, we examined the relationship between their motivation to visit the park and their attachment to the setting. Based on the literature suggesting that natural environments provide humans with a variety of desired psychological, social, and physiological outcomes, we hypothesized that these outcomes would motivate respondents to interact with the park environment and facilitate the development of their attachment to the setting. Our data were analysed using covariance structure analysis. The results of this analysis offered partial support for our hypothesized model. Using multidimensional conceptualizations of motivation and place attachment, we observed that not all dimensions of motivation had a significant effect on the dimensions of place attachment. The valence of the significant predictors, however, was consistent with our hypotheses and prior literature.  相似文献   
994.
It was expected that there would be informal rules of several kinds for working relationships. In the first study subjects rated 33 common rules and a number of relationship-specific rules for three work roles. It was found that certain rules were strongly endorsed for work-mates, superiors and subordinates. These provide a maintenance function by regulating general and relationship-specific sources of conflict. Rules about cooperation, help and fairness applied strongly to work-mates, rules about consideration and skilful use of power to supervisors, rules about using initiative and accepting orders and criticism to subordinates. Rules about reward were also obtained and these tended to be task-focused rather than intimacy sustaining. In the second study one hundred and twenty-four subjects rated the degree of dissatisfaction which they would feel for 11 types of rule violation by each of four work colleagues varying in degree of intimacy. Some level of dissatisfaction was expressed for each rule violation particularly maintenance rules, and the degree of expressed dissatisfaction increased with increased closeness to the work colleague. Study I was replicated in three other countries — Italy, Hong Kong and Japan, and cross-cultural comparisons were made. While there was some cross-cultural consistency for certain maintenance rules, there were cultural differences both in the type of rules endorsed and the strength of endorsement. Japanese relationships in particular were most dissimilar to other countries, characterized by greater homogeneity of overall rule structure within the four work roles, and by lower levels of intimacy and emotional expressiveness towards the other person in each relationship.  相似文献   
995.
The results of model calculations carried out to identify and quantify the input pathways of trace elements into cement and concrete and to estimate the extent to which trace element concentrations in cement may change due to waste utilization are presented. As expected, primary raw materials represented the most important input pathway for trace elements into cement, but the contribution from wastes was not negligible. The use of waste led to a slight increase of the concentrations of cadmium, antimony and zinc in cement. For cobalt, lead and vanadium, this increase was less distinct and for all other trace elements considered, the effect of the use of wastes on trace element concentrations in cement could not be demonstrated clearly. The trace element content of concrete was governed by the aggregates for most elements considered. However, for arsenic, cadmium, lead and zinc, both cement and the additive coal fly ash contributed noticeably to the total trace element concentration in the concrete.  相似文献   
996.
Obstetric complications, such as severe pre-eclampsia, fetal growth restriction, abruptio placentae, or stillbirth are associated with abnormally elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) and β subunit of human chorionic gonadotrophin (βhCG). This has been attributed to placental abnormalities. Women with thrombophilias have been shown to have abnormalities of the placenta resulting in adverse pregnancy outcome in these patients. The purpose of the present study was to evaluate whether women with pregnancy complications and inherited thrombophilias have abnormally elevated second-trimester MSAFP or βhCG. Sixty-two women with pregnancy complications were tested for inherited thrombophilias several months after delivery. The thrombophilia group included 29 women with pregnancy complications and an inherited thrombophilia and the control group included 33 other patients without thrombophilia. Patients in the thrombophilia group had a higher median MoM MSAFP compared to the controls (1.337 vs 1.086, p=0.0516). The incidence of abnormally elevated MSAFP (>2.5 MoM) was also significantly higher in the thrombophilia group compared to controls (21% vs 3%, p=0.04). Neither the median MoM βhCG nor the incidence of abnormally elevated βhCG were significantly different between the groups. We conclude that second trimester MSAFP, but not βhCG, is abnormally elevated in patients with thrombophilia and obstetric complications. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
997.
998.
The 17th BlmSchV fixed the emission limit of 0.1 ng TE/mn 3 for PCDD/F’s produced as a result of waste- and special waste incinerators. This article introduces the different measures implemented to uphold this limit, and discusses their advantages and disadvantages. Methods of optimising the incineration conditions are among the primary measures. Different geometry’s for conventional oven incineration rooms were discussed, and an effective modernisation method was introduced (Temelli nozzles). The chemical and technical basis of an often discussed gasification method, as well as the characteristics of three specialised techniques (Coke Burn technique, Thermo-Select technique and Noell-DBI technique) are explained in this article. Alongside the secondary measures of hot-dust filtration and inhibition being added to the washers in an attempt to achieve PCDD/F adsorption. The most important tertiary measures, namely the SCR technique, along with a variety of coke adsorption techniques are introduced, with their advantages and disadvantages. New techniques such as DeDioxin and Medisorbon are also addressed.  相似文献   
999.
1000.
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