143 research outputs found

    Age-distribution estimation for karst groundwater: Issues of parameterization and complexity in inverse modeling by convolution

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    Convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon (CFC) and tritium (3H) data are available. We show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined. As an example, the model was applied to water from a pumped well open to the Madison aquifer in central USA with input functions of CFC-11, CFC-12, CFC-113, and 3H, and was calibrated to several samples collected during a 16-year period. A bimodal age distribution was modeled to represent quick and slow flow less than 50 years old. The effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow. Quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0–2 and 26–41 years, respectively. The fraction of long-term flow (\u3e50 years) was estimated but was not dateable. The different tracers had different degrees of influence on parameter estimation and uncertainty assessments, where 3H was the most critical, and CFC-113 was least influential

    Age-distribution estimation for karst groundwater: Issues of parameterization and complexity in inverse modeling by convolution

    Get PDF
    Convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon (CFC) and tritium (3H) data are available. We show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined. As an example, the model was applied to water from a pumped well open to the Madison aquifer in central USA with input functions of CFC-11, CFC-12, CFC-113, and 3H, and was calibrated to several samples collected during a 16-year period. A bimodal age distribution was modeled to represent quick and slow flow less than 50 years old. The effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow. Quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0–2 and 26–41 years, respectively. The fraction of long-term flow (\u3e50 years) was estimated but was not dateable. The different tracers had different degrees of influence on parameter estimation and uncertainty assessments, where 3H was the most critical, and CFC-113 was least influential

    Dairy Farm Business Summary: Southeastern New York Region 1990

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    A.E. Ext. 91-17Dairy farmers throughout New York State have been participating in Cornell Cooperative Extension's farm business summary and analysis program since the early 1950's. Each participating farmer receives a comprehensive business summary and analysis of his or her farm business. The information in this report represents an average of the data submitted from farms in the Southeastern New York region

    Liberalization, globalization and the dynamics of democracy in India

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    In the closing decades of the twentieth century there has been an almost complete intellectual triumph of the twin principles of marketization (understood here as referring to the liberalization of domestic markets and freer international mobility of goods, services, financial capital and perhaps, more arguably, labour) and democratization . A paradigm shift of this extent and magnitude would not have occurred in the absence of some broad consensus among policymakers and (sections of) intellectuals around the globe on the desirability of such a change. There seems to be a two-fold causal nexus between marketization and democracy. The first is more direct, stemming from the fact of both systems sharing certain values and attitudes in common. But there is also a second more indirect chain from marketization to democracy, which is predicated via three sub-chains (i) from marketization to growth, (ii) from growth to overall material development welfare and (iii) from material development to social welfare and democracy. We examine each of these sub-links in detail with a view to obtaining a greater understanding of the hypothesized role of free markets in promoting democracies. In the later part of the paper we examine the socio-economic outcomes governing the quality of democracy in a specifically Indian context

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Numerical Ground Water Flow Model for Analysis and Prediction of Artificial Recharge to a Glacial Aquifer

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    Through the Huron Project of the U.S. Bureau of Reclamation\u27s High Plains States Ground-Water Demonstration Program, a glacial aquifer in eastern South Dakota is to be artificially recharged using water from the James River during spring months. One aspect of the study is to test the use of a numerical flow model to analyze the ground-water flow system. Data from approximately 85 observation wells were used to develop aquifer parameters. Calibration efforts were made to optimize the estimated aquifer parameters by the simulation of historical water levels and adjusting model inputs within reasonable hydrological constraints. Calibration of the model was established in three steps: 1) steady-state simulation of the period 1960 through 1973, prior to significant pumping from the aquifer, 2) transient simulation of drought stress in 1976; and 3) monthly transient simulations from January 1990 through May 1991. The ground-water system dynamics were analyzed and predictions of flow patterns during recharge were made to prepare for design and monitoring of the recharge event
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