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151.
Abstract: Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo‐referenced attributes are uncommon over relevant spatial extents. Field inventories provide high‐quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and Geographic Information Systems software has advanced capabilities to delineate stream networks and estimate coarse‐resolution hydrogeomorphic attributes (e.g., gradient). A spatially comprehensive coverage results, but types of modeled outputs may be limited and their accuracy is typically unknown. Capitalizing on strengths in both field and regional digital data, we modeled a synthetic stream network and a variety of hydrogeomorphic attributes for the Oregon Coastal Province. The synthetic network, encompassing 96,000 km of stream, was derived from digital elevation data. We used high‐resolution but spatially restricted data from field inventories and streamflow gauges to evaluate, calibrate, and interpret hydrogeomorphic attributes modeled from digital elevation and precipitation data. The attributes we chose to model (drainage area, mean annual precipitation, mean annual flow, probability of perennial flow, channel gradient, active‐channel width and depth, valley‐floor width, valley‐width index, and valley constraint) have demonstrated value for stream research and management. For most of these attributes, field‐measured, and modeled values were highly correlated, yielding confidence in the modeled outputs. The modeled stream network and attributes have been used for a variety of purposes, including mapping riparian areas, identifying headwater streams likely to transport debris flows, and characterizing the potential of streams to provide high‐quality habitat for salmonids. Our framework and models can be adapted and applied to areas where the necessary field and digital data exist or can be obtained.  相似文献   
152.
Concentrations of organic contaminants were determined in sediment and fish collected annually at six sites around Scotland between 1999 and 2005, as part of the UK National Marine Monitoring Programme. Polycyclic aromatic hydrocarbons (PAHs) and chlorobiphenyls (CBs) were measured in sediment, while CBs and ethoxyresorufin-O-deethylase (EROD) activities were measured in the fish. Highest PAH concentrations in sediment were found at sites where higher coastal influences would be expected (e.g., Clyde and Solway) and four of the six sites gave PAH concentrations above OSPAR background assessment concentrations (BACs). A significant downward trend in the median total PAH concentrations, normalised to total organic carbon (TOC), was found at one of the six sites (Minches). The PAH profiles at all sites were consistent over the 6 year period, indicating that the sites are relatively stable and PAH sources are not changing. There was an indication of a greater petrogenic input on the west coast, with sediment from the Clyde, Solway and Minches having a greater proportion of 2- and 3-ring PAHs and a lower proportion of 5-ring PAHs. CB concentrations at all sites were low compared with UK estuarine sites and similar to sediment from more remote areas: however, BACs were exceeded. No significant trends were detected in either the sediment CB concentrations or patterns at any of the six sites. CB concentrations were significantly higher in fish liver collected from the Clyde. Concentrations at the other five sites were low, with the majority of samples having concentrations for the ICES7 CBs of <500 microg kg(-1) lipid weight. However, individual CB concentrations were still above the BACs. Hepatic EROD activities were measured in male plaice from 2002-2005 and were generally low (<10 pmol min(-1) mg protein(-1)). No temporal trends were detected in either CB concentrations or the EROD activity.  相似文献   
153.
This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine approximately amitrole approximately simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K(ow)) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.  相似文献   
154.
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156.
A 21 -year-old woman with progressively deforming or type III osteogenesis imperfecta (OI) presented for prenatal counselling and diagnosis at 10 weeks' gestation. Family history was non-contributory. At 14.8 weeks' gestation, ultrasonographic examination revealed fetal skeletal hypomineralization, easily compressible fetal cranium, and thickened long bones, indicating that the fetus was also affected. Confirmation of the prenatal diagnosis of OI type III was made following a Caesarean section birth of a male infant with multiple skeletal deformities and blue sclerae implying, in this case, autosomal dominant inheritance.  相似文献   
157.
This research examined whether trainee demographics and pre‐training competence predicted participation in voluntary diversity training. Results indicate that demographic variables had no impact on interest in training (Study One) or on actual training participation (Study Two). However, pre‐training competence levels had a positive effect on both outcomes. More competent trainees expressed more interest in additional training (Study One) and were more likely to attend a voluntary training session (Study Two). The authors suggest that trainees with low competence in the diversity domain are unaware of their low competence levels and therefore are not motivated to participate in training programs designed to increase diversity competence. Implications of these findings for organizations offering voluntary diversity training are discussed. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
158.
It is difficult to make general recommendations that apply to all ecosystems. There is still a relative dearth of studies that allow the manager or visitor to come up with specific practices that are the best for their area. The preferred method of disposal remains to dig a small hole (cat hole) and bury the waste. Other site specific methods are also discussed. Treatment of drinking water has become standard practice for most backcountry travel. With such treatment, there is little evidence currently to suggest that the health hazard to humans is great enough to impose further regulation in areas currently using cat holes.  相似文献   
159.
Although radon can be present within buildings at sufficient levels to pose a health risk, levels can be reduced relatively easily. Recent studies on a group of radon-remediated homes, based on assessment of collective population-average risk coefficients, have estimated the benefits and cost effectiveness accruing from remediation and have confirmed that domestic remediation in UK radon Affected Areas would result in significantly reduced cancer risks to the population in those areas. Although the population-average approach used hitherto has applied occupancy and lung-cancer risk factors, these are potentially misleading in assessing discrete populations. The study reported here uses the recently developed European Community Radon Software (ECRS) to quantify individual risks in a sample of householders who remediated their homes following indications that radon levels exceeded the action level. The study proceeds from population-averaged to 'individual risk' evaluation, successfully comparing individual and collective risk assessments, and demonstrates that those who remediate are not representative of the general population. Health benefits accruing from remediation are three times lower than expected, largely because remediators are older, live in smaller households, and smoke less than the population average, leading to the conclusion that the current strategy employed in the UK is failing to target those most at risk.  相似文献   
160.
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