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31.
Eli Sani 《Resources Policy》1978,4(4):257-278
After examining the concept of a capital shortage, the author analyses the impacts of sectoral shortages in the mineral industries. He analyses the future capital needs of certain segments of the mineral industries and the prospects open to them. Finally, the author discusses some policy proposals to stimulate investment. These include the reduction of corporate tax, increasing investment tax credit, changing depreciation allowances to allow for inflation, and changing the tax treatment of capital gains.  相似文献   
32.
The aim of the present study was to assess the sonographic contour of the increased nuchal translucency (NT) and to correlate this with pregnancy outcome. Fifty sonographic images of fetuses with increased NT [>95th centile thickness of the normal range for crown–rump length (CRL) between 38 and 84 mm] were retrospectively assessed. In all the cases a complete pregnancy and even infancy follow-up (<36 months) was available. The NT appearances were subdivided into two forms: a ‘notched’ or ‘uniform’ appearance. The images were correlated with karyotype results [trisomy 21 (DS) vs euploid cases] and pregnancy outcome. Complicated outcomes were classified as being either DS fetuses, miscarriage or termination of pregnancy because of structural anomaly. Thus 30/35 (86%) of the euploid fetuses had a ‘uniformly’ increased NT, whereas 8/13 DS cases (62%) had a ‘notched’ appearance (Fisher's exact test, p=0.004). Additionally, 27/29 fetuses (93%) which had an uneventful pregnancy outcome had a ‘uniform’ increased NT, whereas 12/26 (57%) of the fetuses which had adverse pregnancy outcome had a ‘notched’ appearance of their NT (Fisher's exact test, p<0.001). Although it was not possible to correlate the sonographic data with post-evacuation microdissection findings, it is possible that a uniformly shaped, increased NT may be more representative of a developmental delay in a normal fetus. Conversely, a ‘notched’ nuchal surface may represent abnormal lymphatic or cardiovascular development more commonly seen in DS fetuses. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
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34.
Abstract

A method for the detection of pentachlorophenol (PCP) residues in chicken liver and fat is presented. A detection limit of 0.002 mg/kg was achieved. Recoveries from liver and fat were in the range 82–88% and 95–97%, respectively.

Low level residues of PCP were found in all 1072 liver and 723 fat samples. These levels were <0.010 mg/kg in 92.7% of the fat and 75.6% of the livers. Only 0.75% of the liver samples had PCP levels>0.1 mg/kg. None of the more toxic impurities of PCP were detected in the chicken tissues.  相似文献   
35.
The tradable planning permit (TPP) policy seeks to limit the land take by development. It can be used in countries where development rights are vested by land-use planning to certain landowners only. TPPs are traded among public authorities. We introduce here a new policy, called the auctioned tradable development rights (ATDR) policy, which takes advantage of unvested rights of development and of trading among private actors. We compare the TPP, the ATDR policy and our baseline land-use planning model using a set of criteria. There are trade-offs within compared models. Both trading policies extend opportunities for land protection from development in exchange for higher transaction costs (highest in the ATDR policy). Trading policies seek also to recapture a part of development rent, decrease rent-seeking, and locate new development more effectively from the investors' perspective. However, trading among public authorities in the TPP model may hinder attaining these effects.  相似文献   
36.
Changes in human behavior are a precursor to measurable impacts of no-take marine reserves. We investigated changes in recreational fishing site selection in response to the 2005 announcement of enforcement in a marine reserve in the Gulf of California, Mexico. We used a novel data set of daily self-reported boating destinations from emergency rescue logbooks for a recreational angling community from 2000 to 2008. Because the reserve system has no experimental control, we modeled the data two ways to test for robustness to model specification. We tested for changes in human fishing behavior with regression and fit a fleet-level discrete choice model to project a. counterfactual scenario. The counterfactual is the statistically constructed ex post expectation of the human behavior we would have observed if the reserve never existed. We included month and year fixed effects in our models to account for seasonal and interannual fluctuations in fishing behavior and catch rates. We detected a decrease in reserve use compared to the counterfactual, indicating that the reserve rapidly experienced a decrease in visitation. However, the reserve's effect to reduce trips diminished with time. These results indicate that the reserve is unlikely to meet its ecological goals without institutional changes that enhance compliance. This illustrates the value of human use data to understanding the processes underlying marine reserve function. We suggest that managers should consider human use with the same frequency, rigor, and tools as they do fishery stocks. Marine reserves directly affect people, and understanding human behavioral responses to marine reserves is an important step in marine reserve management.  相似文献   
37.
Groundwater use is likely to be inefficient in the absence of regulation and hence there is substantial interest in optimal groundwater withdrawals over time. Under an optimal regime withdrawals, pumping lifts, and profits converge to steady-state levels. In this paper we show that optimal steady-state lifts, withdrawals, and marginal user costs can be readily calculated for multi-cell models of confined aquifers. Applications to the design of economically efficient groundwater management policies are discussed, comparisons to previous work and to the safe yield concept are made, and an illustrative example is given.  相似文献   
38.
在WebService结构的基础上,提出一种B/S结构的交通安全管理信息系统;介绍了塔里木石油公路交通安全信息系统的设计模式;阐述了在传统的Web平台的缺点与局限性下选择基于J2EE的系统架构平台的选择的理由;并对基于J2EE平台的多层体系构架设计与实现方法进行详细分析;给出了系统的主要功能模块及其关键技术,如系统的集成、查询、发布和工作流的实现等;最终实现了塔里木石油公路交通安全信息管理的信息化、网络化。  相似文献   
39.
Chemicals such as those used for scent marking, or visual cues such as color badges, can transmit information pertaining to different aspects of individual, group and species recognition and attributes. Here, we show that complex acoustic cues, such as calls also have the capacity for such information transfer. Although songs are usually attributed to birds, rock hyraxes (Procavia capensis) engage in a rich and complex vocalizing behavior that we term ‘singing’. Previous studies on various species have shown that a specific vocalization can closely reflect a specific attribute. Using a series of multiple regressions, we show that a single complex vocalization by the adult male rock hyrax closely reflects numerous individual traits, possibly encoding various types of biologically important information (multiple-messages hypothesis). Our study reveals that hyrax songs provide accurate information regarding body weight, size and condition, social status and hormonal state of the singer. We also show that these independent data are sent in a sequential manner, a pattern that probably allows a better partition of the messages embedded in the song. Our results imply that animals, through complex individual vocalizations, can potentially advertise multiple individual attributes in the same manner as that produced by chemical scent marking. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
40.
采用驾驶适宜性检测仪器,在塔克拉玛干沙漠公路沿线进行驾驶员心理、生理特性的现场测试。结果表明,沙漠公路特殊的环境条件,使得驾驶员表现出有别于一般绿洲公路的心理和行为特性,其主要表现在:驾驶员动体视力较静体视力的平均降幅为44.75%,最高竟达到93%;速度估计和复杂反应时间均小于全国平均;复杂反应错误次数和处置判断错误次数均高于绿洲公路。灰色关联分析表明,沙漠公路驾驶员的年龄、驾龄、驾车时间以及气温与驾驶员的各项生理、心理特性指标都具有较强的相关性,关联度最高达到0.837,其中驾车时间对各项指标的影响最大。  相似文献   
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