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排序方式: 共有993条查询结果,搜索用时 22 毫秒
31.
32.
Viola Seravalli Eric B. Jelin Jena L. Miller Aylin Tekes Luca Vricella Ahmet A. Baschat 《黑龙江环境通报》2017,37(10):1046-1049
Fetoscopic endotracheal occlusion (FETO) is a prenatal treatment that may increase survival in severe congenital diaphragmatic hernia (CDH). In the USA, FETO is offered for isolated severe left-sided CDH in the context of an FDA-approved feasibility study. FETO in non-isolated cases of severe CDH is only performed with a compassionate use exemption from US regulatory bodies. Anomalies frequently associated with CDH include congenital cystic lesions of the lung and cardiac defects. We describe two cases of non-isolated severe left-sided CDH that underwent prenatal FETO, survived after birth and underwent postnatal surgical repair. The potential benefit of FETO in this setting is discussed. © 2017 John Wiley & Sons, Ltd. 相似文献
33.
Peggy A. Johnson Richard D. Hey Eric R. Brown David L. Rosgen 《Journal of the American Water Resources Association》2002,38(1):55-67
ABSTRACT: The number of stream restoration and enhancement projects being implemented is rapidly increasing. At road crossings, a transition must be created from the restored channel through the bridge or culvert opening. Given conflicting design objectives for a naturalized channel and a bridge opening, guidance is needed in the design of the transition. In this paper we describe the use of vanes, cross vanes, and w‐weirs, commonly used in stream restoration and enhancement projects, that may provide an adequate transition at bridges. Laboratory experiments were conducted on vanes and cross vanes to provide a transition for single span bridge abutments and on w‐weirs to provide a transition for double span bridges which have a pier in mid‐channel. The results of the experiments provided design criteria for transitions using each of the three structures. Prior field experience provided guidance on appropriate applications in terms of the stream and bridge characteristics. 相似文献
34.
The 2001 National Land Cover Database (NLCD) provides 30-m resolution estimates of percentage tree canopy and percentage impervious
cover for the conterminous United States. Previous estimates that compared NLCD tree canopy and impervious cover estimates
with photo-interpreted cover estimates within selected counties and places revealed that NLCD underestimates tree and impervious
cover. Based on these previous results, a wall-to-wall comprehensive national analysis was conducted to determine if and how
NLCD derived estimates of tree and impervious cover varies from photo-interpreted values across the conterminous United States.
Results of this analysis reveal that NLCD significantly underestimates tree cover in 64 of the 65 zones used to create the
NCLD cover maps, with a national average underestimation of 9.7% (standard error (SE) = 1.0%) and a maximum underestimation
of 28.4% in mapping zone 3. Impervious cover was also underestimated in 44 zones with an average underestimation of 1.4% (SE = 0.4%)
and a maximum underestimation of 5.7% in mapping zone 56. Understanding the degree of underestimation by mapping zone can
lead to better estimates of tree and impervious cover and a better understanding of the potential limitations associated with
NLCD cover estimates. 相似文献
35.
Eric C. Merten Nathaniel A. Hemstad Randall K. Kolka Raymond M. Newman Elon S. Verry Bruce Vondracek 《Journal of the American Water Resources Association》2010,46(4):733-743
Merten, Eric C., Nathaniel A. Hemstad, Randall K. Kolka, Raymond M. Newman, Elon S. Verry, and Bruce Vondracek, 2010. Recovery of Sediment Characteristics in Moraine, Headwater Streams of Northern Minnesota After Forest Harvest. Journal of the American Water Resources Association (JAWRA) 46(4): 733-743. DOI: 10.1111/j.1752-1688.2010.00445.x Abstract: We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment. 相似文献
36.
37.
Martin H. David Erhard F. Joeres Eric D. Loucks Kenneth W. Potter Stuart S. Rosenthal 《Journal of the American Water Resources Association》1988,24(1):141-148
ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100-year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry. 相似文献
38.
Mejdi Jeguirim Lionel Limousy Eric Fossard 《International Journal of Green Energy》2016,13(6):608-615
Spent coffee grounds (SCG) and coffee husks (CH) were evaluated as biofuels, after densification, for energy production. CH represent a specific problem for the coffee industry due to a low calorific value, high ash content, and a very low bulk density. Hence, the energetic potential of SCG (95 wt%)/CH (5 wt%) blend and pure SCG (100%) were examined. The blend of SCG and CH was limited to 5 wt% of CH because of the low bulk density of CH. Therefore, physicochemical and energetic characterizations of the produced pellets were performed. Thermogravimetric analyses were performed under nitrogen and air atmospheres to evaluate the CH behavior in the blend. Characterization study shows that both produced pellets could reach the French Agropellets standard (AQI). Thermal degradation showed that the mean reactivity of the SCG/HC pellets was higher than pure SCG. Then, combustion experiments were performed in a domestic combustor, after modification of the boiler power in order to improve its energetic performances. The presence of CH led to a rise of CO, NOx, VOC’s, and particle emissions. Nevertheless, the performances of the biofuels are almost in agreement the NF EN 12809 standard. 相似文献
39.
40.
Makadia TH Adetutu EM Simons KL Jardine D Sheppard PJ Ball AS 《Journal of environmental management》2011,92(3):866-871
We investigated the possibility of re-using remediated soils for new bioremediation projects by spiking these soils with waste oil sludge in laboratory based microcosms. The level of Total Petroleum Hydrocarbon (TPH) reduction was high (>80%) in naturally attenuated microcosms and was not significantly improved by biostimulation, bioaugmentation and the combined treatment of bioaugmentation and biostimulation by week 12. This indicated that the observed TPH reduction might have been related to the soil's inherent hydrocarbon-degrading potential. Microbial community analysis (16S rDNA and ITS-based Denaturing Gradient Gel Electrophoresis fingerprints) confirmed the dominance of hydrocarbon degrading genera such as Alcanivorax and Scedosporium. Cluster and Shannon diversity analysis revealed similar but stable bacterial and fungal communities in naturally attenuated and amended microcosms indicating that rapid reduction in TPH may not always be accompanied by changes in soil microbial communities. This study has therefore shown that soils previously used for bioremediation can have an improved hydrocarbon degrading potential which was successfully re-harnessed for new projects. This ability to re-harness this potential is attractive because it substantially reduces operational costs as no additional bioremediation treatments are needed. It can also extend a landfill's lifespan as soils can be re-used again before landfill disposal. 相似文献