42,714 research outputs found

    Water Marketing as an Adaptive Response to the Threat of Climate Change

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    Demographic changes and existing water use patterns have placed tremendous pressures upon water supplies, particularly in the West. Global climate change will exacerbate pressures on water resources. The gradual warming of the atmosphere is certain to change the distribution and availability of water supplies, with potentially severe consequences for freshwater supplies. While climate change will have a significant impact on water resources through changes in the timing and volume of precipitation, altered evaporation rates, and the like, the precise nature, magnitude, timing, and distribution of such climate-induced changes are unknown. This uncertainty complicates the task of water managers who are already faced with escalating demands. This article argues that climate change, and its projected effects on water use and supply, calls for a fundamental reexamination of water institutions. In particular, this article suggests that market-based institutions are well suited to address the additional pressures on water supplies due to climate change. Many aspects of water markets, including their flexibility, decentralized nature, and ability to create and harness economic incentives, make them particularly well suited to address the uncertain water forecast. A gradual shift toward water marketing and market pricing will improve the management of water supplies, ensure more efficient allocation of available water supplies and encourage cost-effective conservation measures

    Dark Matter vs. Neutrinos: The effect of astrophysical uncertainties and timing information on the neutrino floor

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    Future multi-tonne Direct Detection experiments will be sensitive to solar neutrino induced nuclear recoils which form an irreducible background to light Dark Matter searches. Indeed for masses around 6 GeV the spectra of neutrinos and Dark Matter are so similar that experiments will run into a neutrino floor, for which sensitivity increases only marginally with exposure past a certain cross section. In this work we show that this floor can be overcome using the different annual modulation expected from solar neutrinos and Dark Matter. Specifically for cross sections below the neutrino floor the DM signal is observable through a phase shift and a smaller amplitude for the time-dependent event rate. This allows the exclusion power to be improved by up to an order of magnitude for large exposures. In addition we demonstrate that the neutrino floor exists over a wider mass range than has been previously shown, since the large uncertainties in the Dark Matter velocity distribution make the signal spectrum harder to distinguish from the neutrino background. However for most velocity distributions the neutrino floor can still be surpassed using timing information, though certain velocity streams may prove problematic.Comment: 18 pages, 7 figures. v2: Matches version published in JCAP. Includes clarifications to the text and a new figur

    Fables of the Cuyahoga- Reconstructing a History of Environmental Protection

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    The Past and Future of Light Dark Matter Direct Detection

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    We review the status and future of direct searches for light dark matter. We start by answering the question: `Whatever happened to the light dark matter anomalies?' i.e. the fate of the potential dark matter signals observed by the CoGeNT, CRESST-II, CDMS-Si and DAMA/LIBRA experiments. We discuss how the excess events in the first two of these experiments have been explained by previously underestimated backgrounds. For DAMA we summarise the progress and future of mundane explanations for the annual modulation reported in its event rate. Concerning the future of direct detection we focus on the irreducible background from solar neutrinos. We explain broadly how it will affect future searches and summarise efforts to mitigate its effects.Comment: Invited review article for the International Journal of Modern Physics A. 20 pages, 3 figure

    Fitting the annual modulation in DAMA with neutrons from muons and neutrinos

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    The DAMA/LIBRA experiment searches for evidence of Dark Matter scattering off nuclei. Data from DAMA show 9.2 sigma evidence for an annual modulation, consistent with Dark Matter having a cross section around 2x10^(-40) cm^2. However this is excluded by other Direct Detection experiments. We propose an alternative source of annual modulation in the form of neutrons, which have been liberated from material surrounding the detector by a combination of 8B solar neutrinos and atmospheric muons. The phase of the muon modulation lags 30 days behind the data, however we show that adding the modulated neutrino component shifts the phase of the combined signal forward. In addition we estimate that neutrinos and muons need around 1000 m^3 of scattering material in order to generate enough neutrons to constitute the signal. With current data our model gives as good a fit as Dark Matter and we discuss prospects for future experiments to discriminate between the two.Comment: v2: Matches version published in PRL. Includes a new figure. 5 pages, 4 figure

    Projections for measuring the size of the solar core with neutrino-electron scattering

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    We quantify the amount of data needed in order to measure the size and position of the 8^8B neutrino production region within the solar core, for experiments looking at elastic scattering between electrons and solar neutrinos. The directions of the electrons immediately after scattering are strongly correlated with the incident directions of the neutrinos, however this is degraded significantly by the subsequent scattering of these electrons in the detector medium. We generate distributions of such electrons for different neutrino production profiles, and use a maximum likelihood analysis to make projections for future experimental sensitivity. We find that with approximately 20 years worth of data the Super Kamiokande experiment could constrain the central radius of the shell in which 8^8B neutrinos are produced to be less than 0.22 of the total solar radius at 95% confidence.Comment: 5 pages, 2 figures. Matches version accepted to PRL. Improved 2D analysis and results discussio

    A Gate Forever Closed? Retiring Immigration Law’s Post-departure Bar

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    Immigration law’s “post-departure bar” destroys the jurisdiction of either an immigration judge or the Board of Immigration Appeals to hear a motion to reopen or reconsider filed by an alien who is no longer physically within the country. This Note examines the current conflict between the federal circuits regarding the post-departure bar and why the circuits that have decided to strike down the bar in the cases before them have ruled in line with certain trends present in recent Supreme Court immigration cases. Conflict between the circuits has arisen because the governing statute, the Illegal Immigration Reform and Immigrant Responsibility Act of 1996, was enacted without reference to the bar, which had been in place before the Act’s passage. In that statutory silence, the Attorney General promulgated regulations intended to reestablish the bar. In recent years, circuits have taken various positions on the bar’s validity. Many have struck the bar down on the basis of either Chevron deference or the grounds outlined in Union Pacific Railroad Co. v. Brotherhood of Locomotive Engineers, which bars an agency from limiting its jurisdiction in certain situations. Still, other circuits have upheld the bar by using Chevron to conclude that deference to the agency is proper. This Note suggests that the circuits that have struck down the bar are in line with prevailing trends in recent immigration cases decided by the Supreme Court. Further, this Note argues that it does not matter whether a circuit court relies upon Chevron or Union Pacific to strike down the bar, as the use of either precedent to attack the bar serves these trends, and is consistent with the overall direction of American immigration law
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