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201.
科技期刊作为一种专业性较强的学术性刊物,不同于其他通俗性时尚刊物,它的受众面较为狭窄,读者群也受到相应的限制,而要在社会主义市场经济体制下求得生存与发展,必须走向市场、适应新形势,在市场竞争中取得社会效益与经济效益的统一,开拓出新的局面。 相似文献
202.
本文指出,把旅游资源优势转化为经济优势是河南旅游业发展的关键,转化的方式是将旅游资源变为旅游产品,转化的原则是市场的需求,转化的步骤是根据市场需求,对旅游资源进行筛选,加工成适销对路的产品再推向旅游市场. 相似文献
203.
Markus Metz Georg M. Klump Thomas W. P. Friedl 《Behavioral ecology and sociobiology》2007,61(9):1369-1381
The red bishop (Euplectes orix) is a highly polygynous and colonial weaverbird. Males construct several nests within their territories to which they try
to attract females, and females are solely responsible for incubation and raising offspring. In this paper, we describe the
characteristics of the red bishop’s mating system as a biological market and investigate the role of nests built by males
as a traded commodity in a mating market. As timing of breeding in red bishops in arid and semi-arid zones depends on rainfall
patterns which are often unpredictable, there are temporal changes in demand for and supply of nests within a breeding season,
with breeding activities of males and females being highly synchronised. We found that males increased their nest-building
speed with increased female breeding activity independently of rainfall, indicating that supply follows demand in this mating
market. The supply of nests was always larger than the demand for nests. Construction costs for nests increased with demand
for nests as indicated by shorter nest-building duration and shorter building delays between two consecutively built nests
at times of high breeding activity. Males as a trading class are chosen according to the age of their nests offered, with
young nests having a higher probability of being accepted by females. Furthermore, female choosiness with regard to nest age
decreased when their own market value decreased, as predicted by biological market theory. The temporal changes of breeding
activity together with the female preference for young and fresh nests require that males quickly adjust nest-building activity
to varying female demand for new nests. However, males with a better adjustment of building speed to female breeding activity
did not gain higher mating success. 相似文献
204.
205.
An Analysis with the CERT Model of the FSU Market Power in the Carbon Emissions Trading Market 总被引:1,自引:0,他引:1
Jeremy Sager 《Environmental Modeling and Assessment》2003,8(3):219-238
This paper aims to assess the consequences of the amendments made to the Kyoto Protocol during COP 7 in Marrakech. The major issue of hot air and CDM transaction costs is examined using the CERT model to show that primary supply regions, typically those with hot air availability, might control the emissions reduction permit supply market and maximise net export revenues of permit supply by withholding 40 to 60% of available hot air credits. The assumption that primary permit suppliers control permit price via a restriction of hot air supply to the market will inadvertently leave a portion of the market share open to non-Annex B CDM supply, despite potentially extreme variance in CDM transaction costs. A summary table of policy implications on the emissions reduction permit market is also included. 相似文献
206.
207.
The purpose of this study is to quantify the marginal willingness to pay (MWTP) for clean air in China. We provide the first estimate of MWTP for clean air by implementing a hedonic method using housing price and air quality data from Shanghai. Our estimates imply that air pollution has a significant and negative impact on housing price. We also find that the willingness to pay for better air quality varies significantly across different income groups. This paper helps to deepen our understanding of the economic impacts of air pollution in emerging Asian metropolises where residents are suffering from the most severe respiratory health problems. 相似文献
208.
We analyze the bipartisan call to ban US exports of commodity mercury. An export ban can generate positive environmental benefits by increasing the scarcity of mercury in developing economies where significant toxic releases occur. We show, however, that a direct mercury purchase and retirement policy can achieve the same foreign environmental goals without adverse impacts on domestic environmental quality. We present qualitative and quantitative evidence that highlight the potential inefficiencies of a mercury export ban as a method of achieving environmental objectives. 相似文献
209.
SHANNON M. BARBER‐MEYER 《Conservation biology》2010,24(4):918-923
Abstract: Illegal international trade in wildlife (excluding fisheries and timber) has been valued at more than US$20 billion. A more precise figure has not been determined in part because of the clandestine nature of the trade, and for this same reason even regional and local levels of wildlife trade are difficult to assess. The application of recent developments in wildlife field‐survey methods (e.g., occupancy) now allows for a more‐accurate estimation of wildlife trade occurrence, including its hidden components at a variety of scales (e.g., regional, local) and periods (e.g., single season, 1 year, multiple years). Occupancy models have been applied in wildlife field studies to address the problem of false absences when conducting presence–absence surveys. Occupancy surveys differ from traditional presence–absence surveys because they incorporate repeat surveys, allowing for the likelihood of detecting a species (the probability of detection) to be estimated explicitly (in contrast to traditional surveys that often incorrectly treat this probability as close to one to allow for estimation of presence). Occupancy methods can be applied to a variety of wildlife‐trade surveys, including, for example, single‐species availability, links between two illegally traded species (i.e., co‐occurrence), and disease occurrence in live trade. In addition, free user‐friendly software (i.e., PRESENCE) allows even nonstatisticians to adequately address this issue. I simulated a hypothetical wildlife‐trade market survey that resulted in an apparent 20% decline in naïve occupancy (proportion of surveyed towns engaged in the trade) over 2 years, but when I accounted for change in probability of detection over the years the difference in occupancy was not statistically significant. As more sophisticated methods, such as occupancy, are applied to wildlife‐trade market surveys, results will be more robust and defensible and therefore, theoretically, more powerful when presented to conservation policy and decision makers. 相似文献
210.
2012和2013年的废纸市场让很多企业一筹莫展,全球经济不振,国内需求不足,产能过剩,直接影响了造纸行业的生产和销售,作为原料供应商的废纸回收利用行业,必然受到连带影响,整个产业进入低迷阶段.除了外部经济环境的影响,行业内部应该如何调整,产业政策又该怎样引导行业健康发展,将是未来需要持续探讨的课题. 相似文献