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The ecological mechanisms hypothesized to structure species-rich communities range from strict local determinism to neutral ecological drift. We assessed the degree of ecological determinism in tropical plant community structure by analyses of published demographic data; a broad range of spatial, historical, and environmental variables; and the distributions of 33 herbaceous species (plot size = 0.02 ha) and 61 woody species (plot size = 0.09 ha) among 350 plots in a 16-km2 forest landscape (Barro Colorado Island, Panamá). We found a strong degree of cross-landscape dominance by a subset of species whose identities were predictable from sapling survivorship rates under shade. Using canonical ordination we found...
How much does real GDP respond to unanticipated changes in the real price of oil? Commonly used censored VAR models suggest a substantial decline in real GDP in response to unexpected increases in the real price of oil, yet no response to unexpected declines. We show that these estimates are invalid. Based on a structural model that encompasses both symmetric and asymmetric models as special cases, correctly computed impulse responses are of roughly the same magnitude in either direction, consistent with formal tests for symmetric responses. We discuss implications for theoretical models and for policy responses to energy price shocks.
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These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of the metadata file associated with these data. The BLM should be cited as the data source in any products derived from these data.
More than 20 countries generate electricity from geothermal resources and about 60 countries make direct use of geothermal energy. A ten-fold increase in geothermal energy use is foreseeable at the current technology level. Geothermal Energy: An Alternative Resource for the 21st Century provides a readable and coherent account of all facets of geothermal energy development and summarizes the present day knowledge on geothermal resources, their exploration and exploitation. Accounts of geothermal resource models, various exploration techniques, drilling and production technology are discussed within 9 chapters, as well as important concepts and current technological developments.
More than 20 countries generate electricity from geothermal resources and about 60 countries make direct use of geothermal energy. A ten-fold increase in geothermal energy use is foreseeable at the current technology level. Geothermal Energy: An Alternative Resource for the 21st Century provides a readable and coherent account of all facets of geothermal energy development and summarizes the present day knowledge on geothermal resources, their exploration and exploitation. Accounts of geothermal resource models, various exploration techniques, drilling and production technology are discussed within 9 chapters, as well as important concepts and current technological developments.
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This map shows the current and near-term status of aquatic ecosystems, in addition to the input datasets used for the analysis and distribution modeling that were involved in producing these status datasets. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of...
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This map shows the current and near-term status of aquatic ecosystems, in addition to the input datasets used for the analysis and distribution modeling that were involved in producing these status datasets. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of...
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This map shows the status of aquatic ecosystems, in addition to the input datasets used for the analysis and distribution modeling that were involved in producing these status datasets. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of the metadata file associated...
More than 20 countries generate electricity from geothermal resources and about 60 countries make direct use of geothermal energy. A ten-fold increase in geothermal energy use is foreseeable at the current technology level. Geothermal Energy: An Alternative Resource for the 21st Century provides a readable and coherent account of all facets of geothermal energy development and summarizes the present day knowledge on geothermal resources, their exploration and exploitation. Accounts of geothermal resource models, various exploration techniques, drilling and production technology are discussed within 9 chapters, as well as important concepts and current technological developments.
How much does real GDP respond to unanticipated changes in the real price of oil? Commonly used censored VAR models suggest a substantial decline in real GDP in response to unexpected increases in the real price of oil, yet no response to unexpected declines. We show that these estimates are invalid. Based on a structural model that encompasses both symmetric and asymmetric models as special cases, correctly computed impulse responses are of roughly the same magnitude in either direction, consistent with formal tests for symmetric responses. We discuss implications for theoretical models and for policy responses to energy price shocks.
As electricity demand increases, policymakers must make decisions about which energy resources will meet future demands. Much of the recent literature has focused on the contribution of new coal power plants to carbon emissions (Milford et al., 2005; Milford et al., 2007; MIT 2007). However, policymakers and industry are increasingly interested in job creation and economic development analyses to understand the full impacts of new electricity generation projects.1 Additionally, economic development impacts are often a critical piece in building public support for wind power projects. The purpose of this research is to look at the specific factors that drive wind-power-related economic development and to better understand...
As electricity demand increases, policymakers must make decisions about which energy resources will meet future demands. Much of the recent literature has focused on the contribution of new coal power plants to carbon emissions (Milford et al., 2005; Milford et al., 2007; MIT 2007). However, policymakers and industry are increasingly interested in job creation and economic development analyses to understand the full impacts of new electricity generation projects.1 Additionally, economic development impacts are often a critical piece in building public support for wind power projects. The purpose of this research is to look at the specific factors that drive wind-power-related economic development and to better understand...
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This map shows the current and near-term status of aquatic ecosystems, in addition to the input datasets used for the analysis and distribution modeling that were involved in producing these status datasets. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of...
thumbnail
This map shows the status of aquatic ecosystems, in addition to the input datasets used for the analysis and distribution modeling that were involved in producing these status datasets. These data are provided by Bureau of Land Management (BLM) "as is" and may contain errors or omissions. The User assumes the entire risk associated with its use of these data and bears all responsibility in determining whether these data are fit for the User's intended use. These data may not have the accuracy, resolution, completeness, timeliness, or other characteristics appropriate for applications that potential users of the data may contemplate. The User is encouraged to carefully consider the content of the metadata file associated...
The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toeslope) and three stocking systems (continuous, rotational, and nongrazed) on species diversity and percentage of cover of grass, legume, and weed species functional types in southeastern Iowa pastures. Data were collected in 0.2-m2 plots randomly distributed throughout each of four replicate pastures in spring and summer 2000 and 2001. Backslope landscape positions within pastures managed with either continuous or rotational stocking contained the greatest overall diversity of species. Across years, overall species...
This map presents the federal and tribal land areas of the United States. The lands are symbolized by the managing agency. A layer showing federal land boundaries and place names automatically appears when you zoom in to larger scales.


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