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231.
Ramon Valencia Marcela Gerpe John Trimmer Tory Buckman Andrew Z. Mason Per-Erik Olsson 《Marine environmental research》1998,46(1-5)
The effects of injections of 17β-estradiol (E2) and Cd, on the distribution of Cd and the induction of metallothionein (MT) mRNA and vitellogenin mRNA was investigated. Bone and liver were the main organs accumulating Cd. However, E2 redirected the metal accumulation from the bone and liver to the gill, gut and muscle upon exposure to E2. Cd did not induce the hepatic MT mRNA levels in animals treated with E2. The VTG mRNA levels were also reduced following co-injection of E2 and Cd. However, the kidney responded to Cd exposure by upregulating MT mRNA even in the presence of E2 treatment. In the liver the reduced MT mRNA induction led to a redistribution of CD from MT to non-MT proteins. The toxicological significance of these alterations in Cd handling remains to be determined. 相似文献
232.
This paper analyses the institutional foundations of the mussel production sector in Galicia, which is one of the leading producers in the world. After demonstrating the importance of the sector and presenting the theoretical framework and an historical introduction, the paper formulates an agenda of institutional analysis topics from a positive perspective. This agenda includes the problem of the common pool, the role of the State, the legal norms, the property rights system, the organisation of the sector, the rules and public policies and the status quo. This paper presents a case analysis dealing with the relationships between institutions and economic organisation, and furnishes evidence and relevant knowledge for the elaboration of comparative analysis in the economics of natural resources. 相似文献
233.
Evaluation of Bias Associated with Capture Maps Derived from Nonlinear Groundwater Flow Models
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Cara Nadler Kip Allander Greg Pohll Eric Morway Ramon Naranjo Justin Huntington 《Ground water》2018,56(3):458-469
The impact of groundwater withdrawal on surface water is a concern of water users and water managers, particularly in the arid western United States. Capture maps are useful tools to spatially assess the impact of groundwater pumping on water sources (e.g., streamflow depletion) and are being used more frequently for conjunctive management of surface water and groundwater. Capture maps have been derived using linear groundwater flow models and rely on the principle of superposition to demonstrate the effects of pumping in various locations on resources of interest. However, nonlinear models are often necessary to simulate head‐dependent boundary conditions and unconfined aquifers. Capture maps developed using nonlinear models with the principle of superposition may over‐ or underestimate capture magnitude and spatial extent. This paper presents new methods for generating capture difference maps, which assess spatial effects of model nonlinearity on capture fraction sensitivity to pumping rate, and for calculating the bias associated with capture maps. The sensitivity of capture map bias to selected parameters related to model design and conceptualization for the arid western United States is explored. This study finds that the simulation of stream continuity, pumping rates, stream incision, well proximity to capture sources, aquifer hydraulic conductivity, and groundwater evapotranspiration extinction depth substantially affect capture map bias. Capture difference maps demonstrate that regions with large capture fraction differences are indicative of greater potential capture map bias. Understanding both spatial and temporal bias in capture maps derived from nonlinear groundwater flow models improves their utility and defensibility as conjunctive‐use management tools. 相似文献