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排序方式: 共有117条查询结果,搜索用时 15 毫秒
51.
Myeong Y. Chung Matt Beene Shawn Ashkan Charles Krauter Alam S. Hasson 《Atmospheric environment (Oxford, England : 1994)》2010,44(6):786-794
Dairies are believed to be a major source of volatile organic compounds (VOC) in Central California, but few studies have characterized VOC emissions from these facilities. In this work, samples were collected from six sources of VOCs (Silage, Total Mixed Rations, Lagoons, Flushing Lanes, Open Lots and Bedding) at six dairies in Central California during 2006–2007 using emission isolation flux chambers and polished stainless steel canisters. Samples were analyzed by gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Forty-eight VOCs were identified and quantified in the samples, including alcohols, carbonyls, alkanes and aromatics. Silage and Total Mixed Rations are the dominant sources of VOCs tested, with ethanol as the major VOC present. Emissions from the remaining sources are two to three orders of magnitude smaller, with carbonyls and aromatics as the main components. The data suggest that animal feed rather than animal waste are the main source of non-enteric VOC emissions from dairies. 相似文献
52.
Various non-invasive techniques for prenatal diagnosis have been under investigation. We evaluated the success of fetal sexing using a non-invasive technique for obtaining fetal cells, uterine cervix brushing, in combination with FISH. Thirty pregnant women who completed between 6 and 10 weeks of gestation and who were scheduled to undergo pregnancy termination were included in the study. A Pap smear cytobrush was inserted through the external os to a maximum depth of 2 cm and removed while rotating it a full turn. The material that was caught on the brush was spread on four microscope slides. Two-color FISH was used for fetal sexing. Following pregnancy termination, a placental sample was used for full karyotyping. In 29/30 cases FISH diagnosis was confirmed by chromosomal analysis. The only male case in which a Y chromosome was not seen was from a pregnancy of 6 weeks 6 days gestational age. One case was mosaic of 46,XY/47,XXY (25%). In most cases (7/13) the Y chromosome was already identified in the first analyzed slide. With the use of a cytobrush fetal cells can be easily obtained for the purpose of prenatal diagnosis of chromosomal disorders. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
53.
Fuel and leasable minerals mined in the United States have historically been subject to federal royalties while locatable minerals have not. In recent years there have been multiple attempts to alter this policy and subject locatable minerals to federal royalties as well; most recently the preliminary 2012 Obama budget included a gross royalty on hard-rock mining on public lands. This paper analyzes the issue of imposing such federal royalties from both a legal and economic perspective. From a legal perspective, it is argued that the state of western property rights precludes royalties on currently extant claims so revenues from a royalty would not be realized for many years. From an economic perspective, it is argued that the effect on revenue would be smaller than one might anticipate due to such a royalty crowding out state levies or encouraging vertical disintegration on the part of mining firms to avoid much of the burden of the royalty. 相似文献
54.
The multiphase optimization strategy (MOST) and the sequential multiple assignment randomized trial (SMART): two novel evaluation methods for developing optimal training programs 下载免费PDF全文
Current methodologies in training evaluation studies largely employ a single method entitled random confirmatory trials, prompting several concerns. First, practitioners and researchers often analyze the effectiveness of their entire omnibus training, rather than the individual elements or identifiable components of the training program. This slows the testing of theory and development of optimal training programs. Second, a common training is typically administered to all employees within an organization or workgroup; however, certain factors may cause individualized training to be more effective. Given these concerns, the current paper presents two training evaluation methodologies to overcome these problems: the multiphase optimization strategy and sequential multiple assignment randomized trials. The multiphase optimization strategy is a method to evaluate a standard training, which emphasizes the importance of a multi‐stage training evaluation process to analyze individual training elements. In contrast, sequential multiple assignment randomized trial is used to evaluate an adaptive training that varies over time and/or trainees. These methodologies jointly overcome the problems noted earlier, and they can be integrated to address several of the key challenges facing training researchers and practitioners. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
55.
Sikoparija B Pejak-Šikoparija T Radišić P Smith M Soldevilla CG 《Journal of environmental monitoring : JEM》2011,13(2):384-390
Pollen data have been recorded at Novi Sad in Serbia since 2000. The adopted method of producing pollen counts has been the use of five longitudinal transects that examine 19.64% of total sample surface. However, counting five transects is time consuming and so the main objective of this study is to investigate whether reducing the number to three or even two transects would have a significant effect on daily average and bi-hourly pollen concentrations, as well as the main characteristics of the pollen season and long-term trends. This study has shown that there is a loss of accuracy in daily average and bi-hourly pollen concentrations (an increase in % ERROR) as the sub-sampling area is reduced from five to three or two longitudinal transects. However, this loss of accuracy does not impact on the main characteristics of the season or long-term trends. As a result, this study can be used to justify changing the sub-sampling method used at Novi Sad from five to three longitudinal transects. The use of two longitudinal transects has been ruled out because, although quicker, the counts produced: (a) had the greatest amount of % ERROR, (b) altered the amount of influence of the independent variable on the dependent variable (the slope in regression analysis) and (c) the total sampled surface (7.86%) was less than the minimum requirement recommended by the European Aerobiology Society working group on Quality Control (at least 10% of total slide area). 相似文献
56.
Matt Gillen Author Vitae 《Journal of Safety Research》2010,41(3):289-299
The U.S. National Institute for Occupational Safety and Health (NIOSH) conducts research to improve and protect the health and safety of workers. This paper describes the experience of the NIOSH Construction Program with two recent program planning initiatives intended to improve the program: (a) an independent external review of work over the past decade and (b) the development of strategic goals organized into a “National Construction Agenda” to guide a decade of future work. These goals, developed with input from construction industry stakeholders and researchers, are a part of the NIOSH National Occupational Research Agenda (NORA) initiative. The NORA goals are intended to provide an ambitious set of goals for all construction stakeholders to work together on. Both efforts relate to insuring the relevance and impact of research, reflecting an emerging policy perspective that research programs should be judged not just by the quality and quantity of science produced, but by the industry impact and tangible benefit resulting from the research. This paper describes how views on research planning have evolved to incorporate lessons learned about how research leads to improved safety and health for workers. It also describes the process used to develop the goals and the resulting strategic and intermediate goals that comprise the National Construction Agenda. 相似文献
57.
Sang Don Lee M. Worth Calfee Leroy Mickelsen Matt Clayton Abderrahmane Touati 《补救:环境净化治理成本、技术与工艺杂志》2014,24(2):123-133
The cleaning robots, a vacuum‐based robot (R2) and a wetted‐wipe‐based robot (R4), were evaluated in this study to determine their effectiveness for sampling Bacillus atrophaeus spores. The tests were designed to evaluate the benefit of robot sampling on large areas with two different contamination scenarios: a high‐concentration, low spatial extent contamination (hot spot) and a low concentration, high spatial extent contamination (widely dispersed). The hot spot tests were conducted with the high spore contamination (approximately 107 colony forming units [CFUs]) on a limited area (30.5 cm × 30.5 cm), 2 percent of the entire test. The widely dispersed tests were conducted with approximately 0.1 CFUs/cm2 for floor laminate and approximately 10 CFUs/cm2 for carpet surfaces. The widely dispersed tests distributed spores across the test surface and covered approximately 40 percent of the entire test area. The test results showed that both robots successfully sampled a large quantity of spores from carpet and floor laminate surfaces for both test scenarios. Robot performance is discussed in the context of currently used surface sampling methods. © 2014 Wiley Periodicals, Inc.* 相似文献
58.
Environmental Modeling & Assessment - Our study quantifies the impact of climate change on the income of corn farms in Ontario, at the 2068 horizon, under several warming scenarios. It is... 相似文献
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