557 research outputs found

    Influence of deformation axis onto the length free path of screw dislocations in pure fcc materials

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    In this paper the influence of crystal's deformation axis orientation on formation of long, strong dislocation junctions which can be barriers that limit the shear zone has been studied. The probability of strong junctions formation has been obtained on the basis of interdislocation contact interactions model. The length of free path of screw dislocations has been defined for different orientations of crystal's deformation axis

    Ground-Water Quality in Kentucky: Fluoride

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    Fluoride (F-) is an ion of the element fluorine, and is a natural component in most water resources. According to Hem (1989), fluoride concentrations in fresh water are generally less than 1 mg/L (milligrams per liter), and the concentration of fluoride in the world\u27s oceans is about 1.3 mg/L. The source of most fluoride in natural fresh-water resources is various rocks and minerals in bedrock and sediments

    Ground Water in the Kentucky River Basin

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    Most private wells in the Kentucky River Basin are in unconfined or semi-confined bedrock aquifers. Within these aquifers, high-yield zones are irregularly distributed. The most productive wells are drilled into fractured bedrock and alluvium along the Kentucky River floodplain. The data indicate that ground water acts as a buffer to peak and low flows in Kentucky River Basin streams. At current withdrawal rates, ground-water usage does not seem to have an adverse impact on the Kentucky River. Privately owned ground-water sources supply approximately 135,000 people living in the basin-approximately 19 percent of the total population and 36 percent of the rural population. More than 50 percent of residential water supplies in eastern Kentucky rely on ground water. If aquifers are protected from pollution by wellhead protection programs and old wells are retrofitted to prevent direct contamination, then ground water will continue to provide a reliable water supply in many rural areas of the basin. However, for most of the basin, few wells will have yields adequate to supply a large demand. Ground water from present wells will not provide an adequate supply for communities with a population of over a few thousand. Limited discharge data available for springs and large wells in the basin strongly suggest that the potential for ground water to supplement current supplies should not be ignored. Discharge from well fields and springs could be used to augment surface supplies during drought. A better understanding of the distribution and quality of ground-water resources is crucial for the citizens of the basin to fully benefit from ground water

    Research Reports From Status Report: Identification of Appropriate Standards for Corrective Action for a Release from Petroleum Underground Storage Tanks

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    This document is a collection of research reports: Cost of Closure and Remediation for Petroleum Underground Storage Tanks Assessment of Number and Distribution of USTs Analysis of Potable Water Sources in Kentucky Analysis of Well Data and Soil Parameters as Related to the STATSGO Kentucky General Soil Map Petroleum Products: Chemical Composition, Tocxicological and Environmental Data Health Risk Analysis for Selected Petroleum Compounds Summary of Analytical Methods Soil Volume Calculations for UST Installations Generic Organic Containment Pathway Analysis for Components of Petroleum in Soil and Groundwate

    Quantifying decoherence in continuous variable systems

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    We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the purity, some nonclassicality indicators in phase space and, for two-mode states, entanglement measures and total correlations between the modes. Different sets of physically relevant initial configurations are considered, including one- and two-mode Gaussian states, number states, and coherent superpositions. Our analysis shows that, generally, the use of initially squeezed configurations does not help to preserve the coherence of Gaussian states, whereas it can be effective in protecting coherent superpositions of both number states and Gaussian wave packets.Comment: Review article; 36 pages, 19 figures; typos corrected, references adde

    Quantum Theory and Time Asymmetry

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    The relation between quantum measurement and thermodynamically irreversible processes is investigated. The reduction of the state vector is fundamentally asymmetric in time and shows an observer-relatedness which may explain the double interpretation of the state vector as a representation of physical states as well as of information about them. The concept of relevance being used in all statistical theories of irreversible thermodynamics is shown to be based on the same observer-relatedness. Quantum theories of irreversible processes implicitly use an objectivized process of state vector reduction. The conditions for the reduction are discussed, and I speculate that the final (subjective) observer system might even be carried by a spacetime point.Comment: Latex version of a paper published in 1979 (with minor revisions), 18 page

    Non-coding RNAs modulate function of extracellular matrix proteins

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    The extracellular matrix (ECM) creates a multifaceted system for the interaction of diverse structural proteins, matricellular molecules, proteoglycans, hyaluronan, and various glycoproteins that collaborate and bind with each other to produce a bioactive polymer. Alterations in the composition and configuration of ECM elements influence the cellular phenotype, thus participating in the pathogenesis of several human disorders. Recent studies indicate the crucial roles of non-coding RNAs in the modulation of ECM. Several miRNAs such as miR-21, miR-26, miR-19, miR-140, miR-29, miR-30, miR-133 have been dysregulated in disorders that are associated with disruption or breakdown of the ECM. Moreover, expression of MALAT1, PVT1, SRA1, n379519, RMRP, PFL, TUG1, TM1P3, FAS-AS1, PART1, XIST, and expression of other lncRNAs is altered in disorders associated with the modification of ECM components. In the current review, we discuss the role of lncRNAs and miRNAs in the modification of ECM and their relevance with the pathophysiology of human disorders such as cardiac/ lung fibrosis, cardiomyopathy, heart failure, asthma, osteoarthritis, and cancers. © 2021 The Author(s
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