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Twelve second-trimester fetuses with cystic hygroma underwent fetal blood sampling for rapid karyotyping, haematologic evaluation, and blood gas analysis. An abnormal karyotype was found in seven cases: monosomy X in five, trisomy 21 in one, and trisomy 13 in the other. Eight often fetuses undergoing blood gas analysis showed hypoxaemia, five of which were growth-retarded. Nine pregnancies were terminated. Of the remaining three, only one fetus survived the perinatal period.  相似文献   
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Abstract

A tubular device has been developed making it possible to obtain layered samples of loosely aggregated, flocculent material from bogs or eutrophic lakes. The samples are up to 50 cm long and 15 cm in diameter. The sampler is free from protuberances and intact, layered samples can be taken. The tubular part of the sampler is about 85 em long, the walls of the lower 25‐cm portion harbouring a pneumatic closing mechanism which is controlled from above the water surface. An extendible handle for manipulating the sampler and for guiding it into place, is fastened to the upper end of the sampling tube. The performance and the operation of the sampler in the field are described.  相似文献   
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ABSTRACT

An eQUEST model was developed to conduct a simulation study of a natural gas engine-driven heat pump (GEHP) for an office building in Woodstock, Ontario, Canada. Prior to the installation of the GEHP, the heating and cooling demands of the office building were provided by rooftop units (RTUs), comprising of natural gas heater and electric air conditioner. Energy consumption for both GEHP and RTUs were monitored for operation in alternating months. These recorded energy consumptions along with weather data were used in the regression analysis. The developed eQUEST models were validated and calibrated with the regression analysis results with respect to the ASHRAE Guideline 14–2014. The eventual models were then applied to investigate the potential annual energy consumption, greenhouse gas (GHG) emission and energy cost savings achieved by using the GEHP in Woodstock, and other cities in Canada, particularly in Ontario.  相似文献   
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/ The success of the Toxics Release Inventory (TRI) stands in stark contrast to most other environmental regulations in the United States. Between its inception in 1988 and 1995, releases of chemicals listed on the TRI have declined by 45%. We argue the TRI has achieved this regulatory success by creating a mechanism of "populist maxi-min regulation." This style of regulation differs from traditional command-and-control in several ways. First, the majorrole of public agencies is not to set and enforce standards, but to establish an information-rich context for private citizens, interest groups, and firms to solve environmental problems. Second, environmental "standards" are not determined by expert analysis of acceptable risk, but are effectively set at the levels informed citizens will accept. Third, firms adopt pollution prevention and abatement measures in response to a dynamic range of public pressures rather than to formalized agency standards or governmental sanction. Finally, public pressure ruthlessly focuses on the worst polluters-maximum attention to minimum performers-to induce them to adopt more effective environmental practices. TRI has inadvertently set in motion this alternative style of regulation that has, in turn, dramatically reduced toxics emissions in the United States. By properly understanding the mechanisms that drive TRI's accomplishments, more intentional public policy designs can expand the system of populist maxi-min regulation and achieve even more rapid toxics reduction.  相似文献   
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Summary. We investigated the hypothesis that aggregation signals produced by male webbing clothes moths (WCM), Tineola bisselliella (Hum.) (Lepidoptera: Tineidae), and close-range male attractant signals produced by females have a pheromonal basis, at least in part. Gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses of bioactive methanolic extracts of male WCM disclosed three candidate pheromone components: hexadecanoic acid methyl ester (16:Ester), (Z)-9-hexadecenoic acid methyl ester (Z9—16:Ester), and octadecanoic acid methyl ester (18:Ester). In bioassay experiments in a large Plexiglas™ arena, a blend of synthetic 16:Ester plus Z9—16:Ester was attractive to male and virgin (but not mated) female WCM; the 18:Ester was inactive. GC-EAD analyses of pheromone gland extracts from female WCM revealed (E,Z)-2,13-octadecadienal (E2Z13—18:Ald) and (E,Z)-2,13-octadecadienol (E2Z13—18:OH) as candidate sex pheromone components. In arena bioassay experiments, 1—5 female equivalents of synthetic E2Z13—18:Ald (0.2 ng) and E2Z13—18:OH (0.1 ng) were more attractive to male WCM than were two virgin female WCM. We anticipate that the combination of aggregation and sex pheromones, male-produced sonic aggregation signals, and habitat-derived semiochemicals will be highly effective in attracting male and female WCM to commercial traps. Received 12 January 2001; accepted 8 June 2001.  相似文献   
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