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21.
工业革命以来,全球环境发生了前所未有的变化,将可能给地球系统带来灾难性后果,究其原因主要是由于人类活动造成的。人的行为深受意识的影响和制约,环境意识对于环境问题的产生和解决至关重要。本文选取上海、香港两个地区来分析公民对环境的关注度、公民的环保意识、环保行为以及公民对政府环境工作的看法和评价,研究公民对全球环境变化反应的区域差异,为政府制定相关环境保护政策提供理论依据。调查结果显示,上海、香港两地公民在很多环境闷题上具有共识。但是。在对手环境状况好转的期待值、参与环境保护活动的积极性、对人为因素主导力量的认识、环境保护与日常生活的切实关系、为环境保护的支付意愿、对于环境教育内容的认可度等方面存在着一定的差异。  相似文献   
22.
While the world is going into different tourism expectations, the tourism understanding in Turkey is defined as tourism in the sea-sand-sun triangle. However, it is possible to contribute to the income and local development of the indigenous people by developing nature-based tourism. Besides, with the sustainable use and preservation of the natural-cultural assets, the damage of the traditional tourism industry on the natural and cultural environment could be reduced. In this study, it is aimed to bring up the nature-based tourism concept in Çanakkale by evaluating the nature-based tourism industry in the general of Turkey and assessing the natural-cultural resources that Çanakkale comprehends. The most important areas that have a nature-based tourism potential in Çanakkale and the tourism activities that are most suitable for these areas have been determined.  相似文献   
23.
Collections made in the course of long-term field studies on ecology of the northern mole vole Ellobius talpinus Pall. in the Ural Region and neighboring areas (more than 2000 individuals from 24 points of the species range) were used to analyze geographic variation in its coat color (color morphs). On the basis of long-term observations (1985–1999) on marked animals from a polymorphic population (Kurtamyshskii raion, Kurgan oblast), the life spans of males and females and the dependence of life span on population density and structure were estimated in animals of different color morphs. Each color morph of E. talpinus was shown to have specific features of the seasonal dynamics of age structure and migrations.  相似文献   
24.
We examined the impact of seven species of mobile mushroom corals (Fungiidae) on the community structure of sheltered reef slopes in terms of their patterns of migration, habitat use and competition with other benthic organisms. On fringing reefs at Eilat, Red Sea, polyps detached at 1 to 6 cm length, and grew to 11–55 cm length. Attached mushroom corals were oriented vertically in reef cavities. Detached corals migrated downward on the reef slope and onto rubble or soft substratum at the reef base, at 29 to 71 cmyr–1. Mobility decreased with corallum size and extent of undersurface ornamentation. In aquaria, small corals righted themselves and migrated up to 6 cm d–1 by nocturnally inflating and pushing their tissues against the substratum. Autonomous coral behavior and storm-generated water motion appeared to account for most fungiid mobility at Eilat. Mushroom corals did not damage each other upon contact, even in multi-species aggregations, but unilaterally damaged non-fungiid scleractinian corals. Their dominance during contact interactions retards overgrowth by larger attached scleractinians, and mobility allows them to colonize soft substrata not accessible to most other reef corals.  相似文献   
25.
Growth rates of excised apical segments from three Chondrus crispus Stackhouse clones were rapid, reproducible and easily measured using simple equipment. Clonal segments exhibited a high degree of phenotypic stability, with coefficients of variation in growth rates being typically less than 5%. Sensitivity of the assay was demonstrated using 24-h pulses of the toxicants Cu2+ (10 to 150 ppb) and the molluscicide Bayluscide (100 to 500 ppb). As a further demonstration of applicability of this assay system, growth rates were measured over two consecutive 24-h photoperiods using a normally pigmented red gametophytic clone and a green colored mutant derived from it. Growth rates were highest in the first hours of the light phase for both clones, with growth of the green mutant being consistently inferior to that of the normally pigmented one. Significant changes were measured with intervals as short as 4 h using only five apical segments for each treatment. The C. crispus assay described is sensitive, relatively rapid, and statistically robust when applied to toxicant testing in seawater and to physiological studies.  相似文献   
26.
27.
The feasibility of using U.K. coal-fired power station waste materials for artificial reef production is being examined. in June, 1989, an experimental artificial reef was constructed in Poole Bay, off the central south coast of the U.K., using three different mixtures of pulverised fuel ash (PFA), flue gas desulphurisation (FGD) gypsum and slurry, stabilized with cement and formed into blocks. Fifty tonnes of 40 × 20 × 20 cm blocks were formed into eight conical reef units replicating three different PFA/gypsum mixtures and one concrete control. the reef structure is 10m below chart datum on a flat sandy sea-bed.

Combustion of coal concentrates the heavy metal content in the resultant ash. the purpose of stabilization of the ash as blocks is twofold: to immobilize heavy metals (or other components) and to provide hard substratum for the attachment of organisms. to examine the effectiveness of this stabilization and hence the environmental compatibility of the block materials, heavy metal (Cd, Cr, Cu, Pb, Mn, Ni, Zn) content of the blocks has been monitored routinely over two years, to determine leaching rates. Sectional profiles indicate partial replacement of calcium content by magnesium. Associated with this there has also been some redistribution of heavy metals. Only in the case of cadmium has there been a detectable loss from the surface of blocks. Chromium and manganese concentrations appear to have increased. the metal content of the reef epibiota (including ascidians, Ascidia mentula; hydroids, Halecium spp.; bryozoans, Bugula spp. and red algae) growing on the ash blocks has been compared to that of epibiota attached to the concrete controls and surrounding sea-bed. to date no evidence of excess bioaccumulation of metals has been detected.

The physical integrity of the ash reef blocks has been maintained. There is evidence that the blocks are increasing in compressive strength.

An indication of the fishery enhancement potential of the experimental structure is given by the presence of eight commercially fished species (crustaceans and molluscs) including lobsters (Homarus gammarus).  相似文献   
28.
We examined data on sex-specific differences in neonatal weight, litter size and adult female body weight in 32 populations of polygynous ungulates of 18 different species to test for the existence of a trade-off between sex-biased maternal care and the total amount of maternal expenditure. This corresponds to an extension of the hypothesis of Byers and Moodie (1990) that sex-biased maternal care is limited by a high level of maternal expenditure. We did not find any relationship between sex-biased care and two measures of total maternal expenditure. We highlighted high intraspecific variability in sex-biased care and very low intraspecific variability in total maternal expenditure. Even when this between-population variability in sex-biased care was accounted for, no relationship between sex-biased maternal care and maternal expenditure was detected. Apart from difficulties in finding suitable measures for both variables, two other reasons may account for the lack of a relationship between sex-biased maternal care and total maternal expenditure. Firstly, male offspring seem to be more affected than female offspring by harsh environmental conditions. This may lead to the variation observed in the extent of sex-specific differences in birth weight within a single species. If we assume that for a given maternal expenditure reproductive costs incurred by mothers are highest during harsh conditions, this could indicate the existence of a trade-off between sex-biased maternal care and maternal expenditure at the intra-specific level, thereby supporting the Byers and Moodie hypothesis. Secondly, polygyny is only a poor predictor of sex-biased care and factors such as compensatory growth or extended periods of growth may be expected to modify predictions for different species. Thus, environmental conditions and relative effects of maternal care on male and female lifetime reproductive success are better predictors of sex-biased care than total maternal expenditure.Communicated by P.M. Kappeler  相似文献   
29.
Incubation period, hatching success, and emergence percentage in loggerhead (Caretta caretta) nests were quantified during the 1993 and 1995 nesting seasons and following incubation seasons in Minabe, Wakayama, Japan. Sand and nest temperatures were also monitored. Over the seasons, daily mean sand temperature at nest depth fluctuated between 18.0°C and 33.3°C, with a steep increase in the second week of July and a peak in late August. Temperatures inside the nest chambers were a few degrees above those of the surrounding sand at the end of incubation. The incubation period ranged from 46 to 82 days. A significant negative correlation was found between mean sand temperature and incubation period. The relationship conformed to the day-degree concept. There was no significant seasonal trend in hatching success, but many pre-emergent hatchlings were found dead in most of the clutches during the warmest part of the season. Emergence percentage was correlated with mean sand temperature calculated for 4 days before emergence, suggesting that mortality may be due to heat. This heat-related mortality is considered to be a common phenomenon at our study site, because the peak in emergences coincides with the peak in high temperatures. These temperature effects on hatchling mortality must be taken into account in estimates of hatchling sex ratios. Because sand temperatures already exceed the optimal thermal range for incubation, this population is vulnerable to even small temperature increases resulting from global warming.  相似文献   
30.
The most widely used method for fetocide in late termination of pregnancy for fetal abnormalities (TOPFA) consists of injecting of potassium chloride (KCl) into the fetal heart and is likely to be painful after 22 weeks of gestation. We studied ten consecutive women undergoing TOPFA between 22 and 38 weeks. This technique for fetocide consisted of a single umbilical vein puncture under ultrasound guidance with injections of sufentanil 5 µg followed by KCl 2 g. No electrocardiographic modifications could be observed and maternal plasma potassium levels did not show any significant variation throughout the procedure. Fetal umbilical phlebotomy for fetal analgesia followed by fetocide therefore appears to be a safe procedure for the mother and allows the fetus to die without pain when late termination of pregnancy (TOP) is indicated. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
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