排序方式: 共有11条查询结果,搜索用时 49 毫秒
1.
W. F. Carey A. Poulos P. Sharp P. V. Nelson E. F. Robertson J. L. Hughes A. Gill 《黑龙江环境通报》1994,14(9):813-819
Variability in the level of expression of very long chain fatty acids (VLCFAs) is documented in cultured chorionic villus (CV) cells derived from two fetuses, one at risk for an unusual peroxisomal fatty acid β-oxidation defect, and the other at risk for the X-linked form of adrenoleucodystrophy (ALD). Cells from early subcultures of chorionic cells from both cases gave normal values for VLCFA ratios. The results for the fetus at risk for the β-oxidation defect were interpreted to indicate that the fetus was not affected; however, at birth, the infant was clinically and biochemically affected. In the case of the fetus at risk for X-linked ALD, although VLCFAs were normal in subculture 1, the levels of these fatty acids increased dramatically in subculture 3, suggesting an abnormal fetus. Termination of the pregnancy and subsequent biochemical and morphological follow-up confirmed that the fetus was indeed affected by ALD. 相似文献
2.
Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, Meriones persicus, Meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P < 0.01). The total numbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P < 0.01), while the numbers of white blood cells showed no significant difference. 相似文献
3.
Helen M. Poulos Kate E. Miller Michelle L. Kraczkowski Adam W. Welchel Ross Heineman Barry Chernoff 《Environmental management》2014,54(5):1090-1101
We examined the effects of the Zemko Dam removal on the Eightmile River system in Salem, Connecticut, USA. The objective of this research was to quantify spatiotemporal variation in fish community composition in response to small dam removal. We sampled fish abundance over a 6-year period (2005–2010) to quantify changes in fish assemblages prior to dam removal, during drawdown, and for three years following dam removal. Fish population dynamics were examined above the dam, below the dam, and at two reference sites by indicator species analysis, mixed models, non-metric multidimensional scaling, and analysis of similarity. We observed significant shifts in fish relative abundance over time in response to dam removal. Changes in fish species composition were variable, and they occurred within 1 year of drawdown. A complete shift from lentic to lotic fishes failed to occur within 3 years after the dam was removed. However, we did observe increases in fluvial and transition (i.e., pool head, pool tail, or run) specialist fishes both upstream and downstream from the former dam site. Our results demonstrate the importance of dam removal for restoring river connectivity for fish movement. While the long-term effects of dam removal remain uncertain, we conclude that dam removals can have positive benefits on fish assemblages by enhancing river connectivity and fluvial habitat availability. 相似文献
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P. Avramidis K. Nikolaou K. Poulos V. Bekiari A. Vantarakis 《Journal of Coastal Conservation》2017,21(1):115-125
The Klisova lagoon aquatic system belongs to the wetland of Messolonghi - Aetoliko – Klisova Lagoon Complex, located in the western Greece and represents one of the most important Mediterranean lagoon systems, as it is protected by international conventions and is listed in the Natura 2000 European Network. Water physicochemical parameters such as pH, temperature, salinity, dissolved oxygen, nutrients definition, TOC, TN and bacteriological indicators (E.coli and Enterococcus spp.) were analyzed in a time period of 1 year monthly monitoring in five sampling sites along the lagoon. The geographical distribution of these parameters show a clear zonation and partition of the lagoon as the result of: (a) the discharging of poorly treated wastes into the lagoon of Mesolonghi city waste water treatment plant and (b) the interplay between sea water influence via the lagoon inlet and the fresh water inflow via lagoon’s perimeter channels. The lagoon is characterized by seasonal hypoxic conditions, which are responsible for several ecological socks in the past including fish mortalities. The system is threatened by human interference and sedimentological processes such as the longshore drifting and siltation of the lagoon inlet. Measurements should immediately be taken in order to prevent further downgrading of the water quality. 相似文献
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Trees are a major threat to power line security across forested regions of the world. We developed a decision support system
for identifying locations in Connecticut, USA where trees have grown tall enough to make contact with transmission lines during
storms. We used the Random Forest algorithm, danger tree presence/absence data, and 25 raster environmental datasets to develop
(1) an understanding of the abiotic environmental settings that host danger trees and (2) a spatially explicit map of danger
tree distributions across Connecticut power line corridors. Danger trees were prevalent in locations (1) with an infrequent
history of storms; (2) forested and residential land uses; and (3) low to middle elevations. Products from this research can
be transferred to adaptive right-of-way management because they present managers with key information on where danger trees
are likely to occur, and the methods presented herein have great potential for future application to other regions managers
seek to identify high priority areas for danger tree removal. 相似文献
8.
Vegetation management is a critical component of rights-of-way (ROW) maintenance for preventing electrical outages and safety
hazards resulting from tree contact with conductors during storms. Northeast Utility’s (NU) transmission lines are a critical
element of the nation’s power grid; NU is therefore under scrutiny from federal agencies charged with protecting the electrical
transmission infrastructure of the United States. We developed a decision support system to focus right-of-way maintenance
and minimize the potential for a tree fall episode that disables transmission capacity across the state of Connecticut. We
used field data on tree characteristics to develop a system for identifying hazard trees (HTs) in the field using limited
equipment to manage Connecticut power line ROW. Results from this study indicated that the tree height-to-diameter ratio,
total tree height, and live crown ratio were the key characteristics that differentiated potential risk trees (danger trees)
from trees with a high probability of tree fall (HTs). Products from this research can be transferred to adaptive right-of-way
management, and the methods we used have great potential for future application to other regions of the United States and
elsewhere where tree failure can disrupt electrical power. 相似文献
9.
W. F. Carey E. F. Robertson C. Van Crugten A. Poulos P. V. Nelson G. Finikiotis 《黑龙江环境通报》1986,6(3):227-229
At 7·5 weeks gestation, two small chorionic villous biopsies were obtained from a woman at risk for Zellweger's cerebro-hepato-renal syndrome, and were separately established in culture. After 3 weeks, dihydroxyacetone phosphate acyltransferase (DHAP-AT) activity was measured in both cultures. The enzyme was markedly deficient in one cell strain and this was subsequently shown to have a male karyotype. However, the second culture had normal enzyme activity and a female karyotype. The pregnancy was terminated at 11·5 weeks gestation, and follow-up studies on fetal tissues confirmed a male fetus with markedly deficient DHAP-AT activity. 相似文献
10.
Isavela N. Monioudi Aikaterini Karditsa Antonios Chatzipavlis George Alexandrakis Olympos P. Andreadis Adonis F. Velegrakis Serafim E. Poulos George Ghionis Stylianos Petrakis Dafni Sifnioti Thomas Hasiotis Michalis Lipakis Nikolaos Kampanis Theophanis Karambas Emmanouel Marinos 《Regional Environmental Change》2016,16(7):1951-1962
Beaches are both sensitive and critical components of the coastal systems, as they are particularly vulnerable to environmental change (e.g., the sea level rise) and form valuable coastal ecosystems and economic resources. The objective of the present study has been to record the spatial characteristics and other attributes (e.g., topography, sediments and accessibility) of the 71 beaches of the E. Crete (Eastern Mediterranean) that are either already developed or have a reasonable development potential and assess their erosion risk under sea level rise. Beach retreats are predicted by ensembles of six cross-shore (1D) analytical and numerical morphodynamic models, set up/forced on the basis of collected/collated information and three sea level rise scenarios (0.26, 0.82 and 1.86 m); these retreats are then compared with the recorded maximum (dry) beach widths. Projections by the unified ensemble suggest that, in the case of a 0.26 m rise, 80 % of the examined beaches are to retreat by more than 20 and 16 % by more than 50 % of their maximum dry width. In the case of a 0.82 m rise, 72 % of the tested beaches are predicted to retreat by more than 50 % of their dry width and 21 % by a distance at least equal to their observed maximum dry widths. A sea level rise of 1.86 m represents a ‘doom’ scenario, as 75 % of the beaches are predicted to retreat by more than their maximum width. These results may be conservative, as other significant beach erosion factors (e.g., decreasing beach sediment supply) have not been considered. 相似文献