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201.
本实验利用标准短期(48- 96 h)实验室测试测定了包括初级生产者,底栖无脊椎动物,水蚤类动物,软体动物和鱼类在内的15种水生生物对于MON 0818的敏感性。MON 0818是一种商业表面活性剂,由多种聚氧乙烯牛脂胺混合而成。此外本实验使用模糊网纹蚤(Ceriodaphnia dubia)潜在的长期(8 d)毒性,确定了暴露浓度。长期毒性测试中未在任何终端指标中发现显著效果。利用得出的数据和文献记载得到物种敏感度在4种暴露条件下的分布,通过对比物种敏感度分布进行了tier-1危害评估。评估显示在本研究规划下(以综述为原型,研究林业除草剂;12 L标准每公顷,等于4.27 kg每公顷) 最差的情况(无意中以最大标签使用速率直接过量喷洒到15 cm深的水体中)会造成中等危害(43.1%的物种处于暴露中,高于中位有效浓度水平)。在更多以最大使用速率使用的典型情况下,受到损害的物种降至20.9%(6 L标准每公顷,相当于2.14 kg每公顷),在更频繁的雇佣施用速率(2.5 L标准每公顷,相当于0.89 kg每公顷)下,受损物种比例降至6.9%。通过草甘膦在环境中的最大测定浓度计算得到MON 0818的浓度,最终受损物种比例(3.8%)则小于此浓度下受损物种比例(5%)。
精选自Jose L. Rodriguez-Gil, Ryan Prosser, David Poirier, Linda Lissemore, Dean Thompson, Mark Hanson, Keith R. Solomon. Aquatic hazard assessment of MON 0818, a commercial mixture of alkylamine ethoxylates commonly used in glyphosate-containing herbicide formulations. Part 1: Species sensitivity distribution from laboratory acute exposures. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 501–511, July 2017.
DOI: 10.1002/etc.3559
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3559/full 相似文献
202.
An Object-Based Image Analysis of Pinyon and Juniper Woodlands Treated to Reduce Fuels 总被引:1,自引:0,他引:1
April Hulet Bruce A. Roundy Steven L. Petersen Ryan R. Jensen Stephen C. Bunting 《Environmental management》2014,53(3):660-671
Mechanical and prescribed fire treatments are commonly used to reduce fuel loads and maintain or restore sagebrush steppe rangelands across the Great Basin where pinyon (Pinus) and juniper (Juniperus) trees are encroaching and infilling. Geospatial technologies, particularly remote sensing, could potentially be used in these ecosystems to (1) evaluate the longevity of fuel reduction treatments, (2) provide data for planning and designing future fuel-reduction treatments, and (3) assess the spatial distribution of horizontal fuel structure following fuel-reduction treatments. High-spatial resolution color-infrared imagery (0.06-m pixels) was acquired for pinyon and juniper woodland plots where fuels were reduced by either prescribed fire, tree cutting, or mastication at five sites in Oregon, California, Nevada, and Utah. Imagery was taken with a Vexcel UltraCam X digital camera in June 2009. Within each treatment plot, ground cover was measured as part of the Sagebrush Steppe Treatment Evaluation Project. Trimble eCognition Developer was used to classify land cover classes using object-based image analysis (OBIA) techniques. Differences between cover estimates using OBIA and ground-measurements were not consistently higher or lower for any land cover class and when evaluated for individual sites, were within ±5 % of each other. The overall accuracy and the K hat statistic for classified thematic maps for each treatment were: prescribed burn 85 % and 0.81; cut and fell 82 % and 0.77, and mastication 84 % and 0.80. Although cover assessments from OBIA differed somewhat from ground measurements, they are sufficiently accurate to evaluate treatment success and for supporting a broad range of management concerns. 相似文献
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Jiyoung Ahn Ryan Okerlund Andrew Fry Eric G. Eddings 《International Journal of Greenhouse Gas Control》2011
The purpose of this study was to investigate the effects of increased oxygen and carbon dioxide concentration on the formation of sulfur trioxide during oxy-coal combustion in two different types of pilot-scale furnaces: a pulverized-coal and a circulating-fluidized-bed-fired system.For pulverized-coal (PC) testing, concentrations of SO3 and SO2 were significantly higher for oxy-fired conditions as compared to air-fired conditions. For a high-sulfur Illinois bituminous coal, SO3 concentrations were 4–6 times greater on average. When firing a low-sulfur Utah Bituminous coal, SO3 concentrations were similar for oxy-firing vs. air-firing, and the overall levels were very low compared to the Illinois coal, consistent with differences in the fuel sulfur contents. PC-fired emissions on a normalized mass basis (mass SO3 per unit energy input) indicated higher SO3 emissions under air-fired conditions vs. oxy-firing, for both the Illinois and Utah coals.Circulating fluidized bed testing was also carried out using the low-sulfur Utah coal, and SO3 concentrations were notably higher for oxy-firing vs. air-firing, in contrast to the similar concentration levels observed for PC-firing. When compared on a normalized mass basis, the emissions were similar for both air- and oxy-firing, which is also in contrast to the PC-fired results for this coal. 相似文献
206.
Chrysoula Gubili Ryan Johnson Enrico Gennari W. Hermann Oosthuizen Deon Kotze Mike Me?er David W. Sims Catherine S. Jones Leslie Robert Noble 《Marine Biology》2009,156(10):2199-2207
Visual identification of naturally acquired marks has been a popular if subjective method of animal identification and population
estimation over the last 40 years. Molecular genetics has also independently developed objective individual marking techniques
during the same period. Here, we assess the concordance of individual great white shark (Carcharodon carharias) dorsal fin recognition and identification, using seven microsatellite loci as the independent unbiased arbiter, over a period
of 5 years. As a monitoring technique, fin photographs offer a very good individual identification key for white sharks over
a relatively short period of time (5 years), matching with genetic data in about 85% of cases, whilst caution and a continuously
updated database is required for animal recognition over a longer period. 相似文献
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Best‐practice recommendations for estimating interaction effects using moderated multiple regression
An interaction effect indicates that a relationship is contingent upon the values of another (moderator) variable. Thus, interaction effects describe conditions under which relationships change in strength and/or direction. Understanding interaction effects is essential for the advancement of the organizational sciences because they highlight a theory's boundary conditions. We describe procedures for estimating and interpreting interaction effects using moderated multiple regression (MMR). We distill the technical literature for a general readership of organizational science researchers and include specific best‐practice recommendations regarding actions researchers can take before and after data collection to improve the accuracy of MMR‐based conclusions regarding interaction effects. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
210.
William F. Ryan Bruce G. Doddridge Russell R. Dickerson Raymond M. Morales Kristen A. Hallock Paul T. Roberts 《Journal of the Air & Waste Management Association (1995)》2013,63(9):786-797
ABSTRACT Ozone (O3) concentrations in the Baltimore-Washington (B-W) metropolitan area frequently exceed the National Ambient Air Quality Standard (NAAQS) in the summer months. The most extreme O3 events occur in multi-day high O3 episodes.1 These events can be regional in scale, with O3 concentrations exceeding the NAAQS at numerous locations along the eastern U.S. seaboard, and are typically associated with slow-moving or stagnant high pressure systems.2-5 In the B-W region, the most extreme events typically occur with surface high pressure overhead or just west of the region and an upper air high-pressure area (ridge) to the west or northwest.1 Besides providing conditions conducive to local O3 production (subsidence and strong low-level inversions, weak horizontal winds, little cloud cover), this weather pattern may also result in transport of O3 and its precursors from heavily industrialized areas west and north of the B-W region. In this paper, observations and back trajectories made during the severe regional O3 event of July 12-15, 1995, are used to confirm the hypothesis that significant regional-scale transport of O3 and its precursors occur during extreme O3 events of the standard type in the B-W area. 相似文献