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991.
Papanastasiou DK Fidaros D Bartzanas T Kittas C 《Environmental monitoring and assessment》2011,183(1-4):285-296
Atmospheric pollutants from livestock operations influence air quality inside livestock buildings and the air exhausted from them. The climate that prevails inside the building affects human and animal health and welfare, as well as productivity, while emissions from the building contribute to environmental pollution. The aim of this study was to examine the variation of two climatic parameters (namely temperature and relative humidity) and the levels of particulate matter of different sizes (PM10-PM2.5-PM1), as well as the relationships between them, inside a typical Greek naturally ventilated livestock building that hosts mainly sheep. The concentration of particles was recorded during a 45-day period (27/11-10/1), while temperature and relative humidity were observed during an almost 1-year period. The analysis revealed that the variation of outdoor weather conditions significantly influenced the indoor environment, as temperature and relative humidity inside the building varied in accordance to the outside climate conditions. Temperature remained higher indoors than outdoors during the winter and extremely low values were not recorded inside the building. However, the tolerable relative humidity levels recommended by the International Commission of Agricultural Engineering (CIGR) were fulfilled only in 47% of the hours during the almost 1-year period that was examined. This fact indicates that although temperature was satisfactorily controlled, the control of relative humidity was deficient. The concentration of particulate matter was increased during the cold winter days due to poor ventilation. The maximum daily average value of PM10, PM2.5 and PM1 concentration equaled to 363, 61 and 30?μg/m(3) respectively. The concentration of the coarse particles was strongly influenced by the farming activities that were daily taking place in the building, the dust resuspension being considered as the dominant source. A significant part of the fine particles were secondary, which the production of could be attributed to an increase in relative humidity levels. It is concluded that measures have to be adopted in order to achieve sufficient ventilation and to reduce particulate matter levels. 相似文献
992.
Le MH Buddenbaum JE Burns RE Shonka JJ Gaffney SH Donovan EP Flack SM Widner TE 《Journal of environmental monitoring : JEM》2011,13(10):2735-2747
From 1999 through 2010, a team of scientists and engineers systematically reviewed approximately eight million classified and unclassified documents at Los Alamos National Laboratory (LANL) that describe historical off-site releases of radionuclides and chemicals in order to determine the extent to which a full-scale dose reconstruction for releases is warranted and/or feasible. As a part of this effort, a relative ranking of historical airborne and waterborne radionuclide releases from LANL was established using priority index (PI) values that were calculated from estimated annual quantities released and the maximum allowable effluent concentrations according to The U.S. Nuclear Regulatory Commission (USNRC). Chemical releases were ranked based on annual usage estimates and U.S. Environmental Protection Agency (USEPA) toxicity values. PI results for airborne radionuclides indicate that early plutonium operations were of most concern between 1948 and 1961, in 1967, and again from 1970 through 1973. Airborne releases of uranium were found to be of most interest for 1968, from 1974 through 1978, and again in 1996. Mixed fission products yielded the highest PI value for 1969. Mixed activation product releases yielded the highest PI values from 1979 to 1995. For waterborne releases, results indicate that plutonium is of most concern for all years evaluated with the exception of 1956 when (90)Sr yielded the highest PI value. The prioritization of chemical releases indicate that four of the top five ranked chemicals were organic solvents that were commonly used in chemical processing and for cleaning. Trichloroethylene ranked highest, indicating highest relative potential for health effects, for both cancer and non-cancer effects. Documents also indicate that beryllium was used in significant quantities, which could have lead to residential exposures exceeding established environmental and occupational exposure limits, and warrants further consideration. In part because of the close proximity of residents to LANL, further study of historical LANL releases and the potential impact to public health is recommended for those materials with the largest priority index values; namely, plutonium, uranium, and selected chemicals. 相似文献
993.
Codfishes, the Gadiformes, are quite abundant in modern temperate and polar waters with a fossil record ranging back into
the Palaeogene. The oldest records are from the Danian and Selandian of Europe and South Australia. The bipolar distribution
early in their evolutionary history implies that their origin must have occurred quite early in the Palaeocene, or even in
the Late Cretaceous with subsequent rapid diversification. By the Eocene, gadiforms were highly abundant and widespread. With
the exception of gadiforms, no Eocene Antarctic teleostean group is present in the modern Antarctic fauna. Here, we review
the early evolution and diversification of gadiforms in general and of macrouroids in particular. We also describe the undoubtedly
oldest skeletal macrourid specimen with otoliths preserved in situ. It is the first definitive record of this group from the
Eocene of Antarctica filling a gap in its stratigraphic distribution. The fossil record of gadiforms in general and macrouroids
in particular indicates that the origin of both was in shallow shelf environments but with adaptations to deep-water settings
early in their evolution. While gadoids seemingly originated in the earliest Palaeogene and rapidly experienced a first major
radiation event in the eastern North Atlantic and/or North Sea Basin, macrouroids evolved in the Southern Ocean and migrated
northwards into the South Atlantic before the establishment of the circum-Antarctic current and subsequent isolation of the
Antarctic fish fauna. These two timely and regional separated adaptive radiation events in the Palaeogene gave rise to their
modern taxonomic diversity and global distribution. 相似文献
994.
Ronald L. Thomas MD 《黑龙江环境通报》1992,12(11):919-923
Cystic hygromas have historically been associated with a grim prognosis when discovered during prenatal sonographic study of the fetus. This same grim prognosis is not observed by the paediatric surgeon who evaluates the neonate or paediatric patient. We present a fetal patient with a massive anterior cystic hygroma discovered in the third trimester prior to 30 weeks. This case and a review of the literature suggest tailoring the prognosis by category when counselling patients: (1) first trimester, normal karyotype-good; (2) first trimester, abnormal karyotype-poor; (3) second trimester and early third-poor to guarded; and (4) mid to late third trimester-good. 相似文献
995.
恢复力与可持续发展:在瞬息万变的世界中增强适应能力 总被引:27,自引:0,他引:27
Carl Folke Steve Carpenter Thomas Elmqvist Lance Gunderson C.S. Holling Brian Walker 《Ambio-人类环境杂志》2002,31(5):437-440
由于在以往的自然资源政策上逐渐暴露出了两个带根本性的错误,人们开始意识到在环境管理理论和实践方面需要进行一场全球性的重大改革.第一个错误是毫无保留地假定生态系统对人类利用所作出的反应是呈线性关系、是可以预测和控制的.第二个错误是认定人类社会与天然系统可以分别对待,不必联系在一起进行考虑.然而,从世界各地收集到的证据表明,天然系统和人类社会系统是以非线性方式运行的、在其动态运行过程中均有其显著的极限,而且,人类社会与生态系统表现为一种紧密相联的、复杂的且不断演变的综合系统.本文是代表瑞典政府环境咨询委员会编写的一份报告的摘要,这份报告是作为向2002年8月26日~9月4日在南非约翰内斯堡召开的可持续发展世界首脑会议献礼的论文而撰写的.从概念上说,恢复力是一种能缓冲变化所带来的影响、学习知识和求得发展的能力,我们将它作为在一个纷纭复杂、快速变化的世界中,是否真正懂得如何维护和提高适应能力的一种参照标准来使用.在社会、生态综合系统中,有两种有用的工具可用来提高恢复力,一种是结构严谨的工作方案,另一种是积极的适应力管理.这两种工具都需要而且有助于形成这样一种社会环境:具有灵活开放的组织机构和多层次的监管体制,允许学习适应力方面的知识和提高适应力但又不妨碍对未来的发展作出选择. 相似文献
996.
Kolpin DW Hoerger CC Meyer MT Wettstein FE Hubbard LE Bucheli TD 《Journal of environmental quality》2010,39(6):2089-2099
This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km2 to > 836,000 km2. Atrazine (herbicide) also was measured in all samples as a frame-of-reference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). The nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L(-1) (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly rake place in surface water are poorly understood and have yet to be systematically investigated in environmental studies. 相似文献
997.
Recreational beach use with off-road vehicles is popular, but potentially harmful from an environmental perspective. Beaches
are important habitats to invertebrates such as ghost crabs of the genus Ocyopde, which excavate extensive and elaborate burrows.
Ghost crabs are sensitive to human pressures and changes in burrow architecture may thus be a consequence of disturbance by
vehicles—the predictive hypothesis of this article. This was tested during the austral spring and summer by comparing 305
burrow casts between beaches open and closed to vehicles in Eastern Australia. Traffic influenced burrow architecture: there
were smaller crabs on vehicle-impacted beaches, and after the peak traffic period (Christmas and New Year holidays), these
crabs had tunnelled deeper into the sediment on shores rutted by cars. Crabs constructed all types of previously described
burrows, but, significantly, smaller crabs from vehicle-impacted beaches simplified their shapes following heavy traffic disturbance
from four (I, J, Y, M) to only two types (I, Y). These data support a model of active behavioural responses to disturbance
from vehicles, extending the known effects of beach traffic to impacts on behavioural traits of the beach fauna. 相似文献
998.
Oil spill contingency planners need an improved approach to understanding and planning for the human dimensions of oil spills.
Drawing on existing literature in social impact assessment, natural hazards, human ecology, adaptive management, global change
and sustainability, we develop an integrative approach to understanding and portraying the human dimensions impacts of stressors
associated with oil spill events. Our approach is based on three fundamental conclusions that are drawn from this literature
review. First, it is productive to acknowledge that, while stressors can produce human impacts directly, they mainly affect
intermediary processes and changes to these processes produce human impacts. Second, causal chain modeling taken from hazard
management literature provides a means to document how oil spill stressors change processes and produce human impacts. Third,
concepts from the global change literature on vulnerability enrich causal models in ways that make more obvious how management
interventions lessen hazards and mitigate associated harm. Using examples from recent spill events, we illustrate how these
conclusions can be used to diagrammatically portray the human dimensions of oil spills. 相似文献
999.
Justin L. Milner Cristina Bunget Fadi Abu-Farha Thomas Kurfess Vincent H. Hammond 《Journal of Manufacturing Processes》2013,15(2):219-226
Nanostructured materials are a relatively new class of materials that exhibit advanced mechanical properties, thus improving performance and capabilities of products, with potential applications in the automotive, aerospace and defense industries. Among the severe plastic deformation (SPD) methods currently used for achieving nanoscale structures, accumulative roll bonding (ARB) is the most favorable method to produce grain refinement for continuous production of metallic sheets at a bulk scale.In this article, a model that describes the evolution of material strength due to processing via accumulative roll bonding was developed. ARB experiments were conducted on CP-Ti Grade 2 at a selected set of conditions. The results showed significant grain refinement in the microstructure (down to ~120 nm) and a two-fold increase in tensile strength as compared to the as-received material. The developed model was validated using the experimental data, and exhibited a good fit over the entire range of ARB processing cycles. To further validate the model and ensure its robustness for a wider array of materials (beyond CP-Ti), a review of efforts on ARB processing was carried out for five other materials with different initial microstructures, mechanical properties, and even crystalline structures. The model was still able to capture the strengthening trends in all considered materials. 相似文献
1000.