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211.
The Cambro-Ordovician anomalocaridids are large ecdysozoans commonly regarded as ancestors of the arthropods and apex predators. Predation is indicated partly by the presence of an unusual “peytoia”-type oral cone, which is a tetraradial outer ring of 32 plates, four of which are enlarged and in perpendicular arrangement. This oral cone morphology was considered a highly consistent and defining characteristic of well-known Burgess Shale taxa. It is here shown that Anomalocaris has a different oral cone, with only three large plates and a variable number of smaller and medium plates. Its functional morphology suggests that suction, rather than biting, was used for food ingestion, and that anomalocaridids in general employed a range of different scavenging and predatory feeding strategies. Removing anomalocaridids from the position of highly specialized trilobite predators forces a reconsideration of the ecological structure of the earliest marine animal communities in the Cambrian. 相似文献
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Scale-up of a hollow-fiber-membrane (HFM) bioreactor treating trichloroethylene- (TCE-) contaminated water via co-metabolism with the methanotroph Methylosinus trichosporium OB3b PP358 was investigated through cost comparisons, bioreactor experiments, and mathematical modeling. Cost comparisons, based on a hypothetical treatment scenario of 568-L/min (150-gpm) flowrate with an influent TCE concentration of 100 microg/L, resulted in a configuration of treatment trains with two HFM modules in series and an overall annual cost of US dollar 0.36/m3 treated. Biological experiments were conducted with short lumen and shell residence times, 0.16 and 0.40 min, respectively, as a result of the cost comparisons. A new variable, specific transformation, was defined for characterizing the cometabolic transformation in continuous-flow systems, and values as large as 38.5 microg TCE/mg total suspended solids were sustainable for TCE treatment. Using mathematical modeling, HFM bioreactor system design was investigated, resulting in a five-step system design strategy to facilitate sizing of the unit processes. 相似文献
216.
Bevin Keen Ellen England Timothy Webb Summer Bartczak Charles Bleckmann 《补救:环境净化治理成本、技术与工艺杂志》2006,16(4):71-80
Environmental compliance requirements periodically impact the military's ability to use all installation resources. In response, environmental management strategies have been developed to ensure compliance and allow site closure. This study examines the relationship between environmental management strategies and environmental compliance at U.S. Marine Corps (USMC) installations via analysis of environmental compliance audit scores. Five environmental scores of interest from 1998 to 2004 audits—which include total compliance, total management, audit management, policy management, and training management—were subjected to statistical analysis. Results showed the USMC met environmental compliance and management standards, despite limited resources. High management strategy scores were moderately correlated with high total compliance scores. Total management scores improved over time, and noncompliance was most often associated with a lack of resources and plans. © 2006 Wiley Periodicals, Inc. 相似文献
217.
James C. Hower Uschi M. Graham Amy S. Wong J.David Robertson Bethel O. Haeberlin Gerald A. Thomas William H. Schram 《Waste management (New York, N.Y.)》1997,17(8):523-533
Two Kentucky power plants burning similar blends of high-sulfur western Kentucky and southern Indiana coal provide a unique opportunity to examine the variations in coal combustion by-products due to differences in the method of wet flue-gas desulfurization (FGD). One plant employed carbide lime-based scrubbing for two units and a dual-alkali process for the third unit. The second plant employed a Mississippian limestone from Kentucky for all four units. This study provides an example of optical and SEM petrographic techniques, supplemented by chemical analyses, applied to the study of, at least from the geologic perspective, non-traditional materials. The coal sources comprise a blend of high volatile C and B bituminous, high vitrinite (85–90%, mmf), high-sulfur (> 3%, dry) coals. The fly ash is dominated by glassy phases (70–80%) with about 5–10% spinel (predominately magnetite), 3–10% quartz, and 4–10% isotropic coke comprising the remaining portion of the ash. SEM observations indicate that the glassy particles exhibit a bimodal size distribution with sub-micron glass spheres and a population of larger (several 10s of microns) spheres. The bottom ash has higher proportions of spinels and mullite, with negligible carbon forms, compared to the fly ash from the same units. Fly ashes were observed to be lower in Fe and higher in Al, Si, and S compared to the bottom ashes. Carbide lime, a by-product of acetylene manufacture, soda ash, and limestone were the reagents used in the flue-gas desulfurization processes. The primary FGD by-product is a calcium sulfite slurry which is vacuum filtered and mixed with fly ash and, usually, lime, to form a stable product for disposal. The FGD by-products have some potential, as yet unrealized, for utilization. 相似文献
218.
The method of anthropoecological landscape stability (AELS) has been applied experimentally to a territorial unit, forming
a closed watershed with more of less precisely defined material, energy, and population flows. This article presents data-driven
results of monitoring and conclusions on optimizing features derived from two object-oriented expert systems—the FORELIS,
giving heuristically optimal conditions for forest compositions on the site in the prevailing immission situation, and AGRILIS—the
agricultural expert system having the scope of finding suitable forms of agriculture with respect to natural conditions and
suitable actual production facilities. The results of the study fully confirmed the feasibility of applying expert systems
to actual conditions, and no significant errors in the results of the expert systems compared to indications by monitoring
have been disclosed. 相似文献
219.
We conducted breeding bird surveys in Minnesota, Wisconsin, and South Dakota in 12 hybrid poplar plantations and surrounding landscapes from 1992 to 1994. Plantations varied in age, shape, composition of surrounding landscape, and internal vegetative heterogeneity. Numbers of breeding bird individuals and species in plantations were lower than in surrounding forest/shrub habitat, but higher than in row crops. Numbers of individuals observed within several bird groups based on migratory status and habitat preference also differed among plantations and surrounding land-use types. Most differences were between numbers in plantations and row crops. Year-to-year changes in bird species composition in plantations were more likely in plantations between ages 2 and 4 years than in younger or older plantations. Correlative evidence from canonical correspondence analysis illustrated that plantation bird communities were related to habitat in surrounding landscapes, plantation age, size, latitude, and longitude. Additionally, more heterogeneous plantations had more species, individuals, and numbers of long-distance migrants. Plantations will likely not support bird communities that are comparable to natural forests in either species composition or species diversity. A goal would be to position them in the landscape to minimize impacts on regional biodiversity. This could be accomplished by maintaining structural diversity of plantations by creating a broad range of successional stages (ages) throughout plantations within a region. Size and connectivity of existing forest fragments may be increased by plantations, but fragmentation of natural open areas should be avoided. 相似文献
220.
Recent research on influence tactics has focused on the benefits that accrue as a result of using such tactics. The current study utilizes meta‐analytic techniques to estimate the true population correlations between various influence tactics and work‐related outcomes. Results indicate that ingratiation and rationality have positive effects on work outcomes. Additional analyses suggest that these and other influence tactics have significant effects in certain situations and on specific work outcomes. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献