29 research outputs found

    The Generation of Flood Damage Time Sequences

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    There is a need in water resources planning to develop a procedure for determining the time pattern in which flood damages occur as a function of the rise and fall of the flood hydrograph. The widely-used approach for estimation of flood damages does not take into account the fact that the frequency of the annual flood peak may not be the same as the frequency of the total annual flood damages. As examples, several small storms during the year may do more damage than a single larger storm, or flood damages may be reduced by a reduction in flood duration rather than the flood peaks. This report presents a digital computer subroutine DAMAGE which can be used to estimate the direct and indirect damages to property in the four basic categories of crop, field, urban, and public facilities as functions of the depth and duration of flooding, seasons, and the time laps between flood events. DAMAGE may be called with recorded or simulated annual hydrographs and used to analyze the time pattern of damages in the flood plain for optimizing the policies for operating reservoir flood control storage or for estimating the average annual damages for use in formulation of alternative flood control schemes

    A Perspective on Economic Impact

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    The institutions responsible for water resources management in the United States have originated as political responses to major social issues. Each agency institutionalized a procedure for structuring and comparing alternatives in the formulation of its total program. Each agency originally sought to promote effective resolution of its social issue (flood control, development of arid lands, soil erosion, etc.), but more recent efforts have sought better coordination among agency practices through a common procedure largely derived from economic theory. Any procedure, however, varies in application with the interpretation and judgment of individual planners. Today, public pressures have brought political directives requiring consideration of the local and nationwide impacts of projects that occur through direct, indirect, and secondary means in the spheres of economic, social and environmental effects. The body of the study reviews fourteen specific impact issues with the goals of providing planners a methodology for dealing with each one and of providing the theoretically inclined a basis for improving each methodology. The issues are reservoir effects on local property values, reservoir effects on the economy of the local county, changes in income and employment patterns around large reservoirs, patterns of land use change around reservoirs, reservoir effects on revenues and expenditures of local government, reservoir recreation benefits, application of marginal economic analysis to reservoir recreation planning, economic value of natural areas for recreational hunting, for stream fishing, the personal value of real property to its owner, reservoir project caused income redistribution, achievement of more flexible procedures for reservoir operation in order to match changes in demand for project output with time, estimation of flood damages by the time pattern in which they occur, and operation of reservoir systems for flood control. Each study ls presented in detail in a referenced report, and this report discusses the significance of the findings of the studies, individually and as a group

    Combinations of single-top-quark production cross-section measurements and vertical bar f(LV)V(tb)vertical bar determinations at root s=7 and 8 TeV with the ATLAS and CMS experiments

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    This paper presents the combinations of single-top-quark production cross-section measurements by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at = 7 and 8 TeV corresponding to integrated luminosities of 1.17 to 5.1 fb(-1) at = 7 TeV and 12.2 to 20.3 fb(-1) at = 8 TeV. These combinations are performed per centre-of-mass energy and for each production mode: t-channel, tW, and s-channel. The combined t-channel cross-sections are 67.5 +/- 5.7 pb and 87.7 +/- 5.8 pb at = 7 and 8 TeV respectively. The combined tW cross-sections are 16.3 +/- 4.1 pb and 23.1 +/- 3.6 pb at = 7 and 8 TeV respectively. For the s-channel cross-section, the combination yields 4.9 +/- 1.4 pb at = 8 TeV. The square of the magnitude of the CKM matrix element V-tb multiplied by a form factor f(LV) is determined for each production mode and centre-of-mass energy, using the ratio of the measured cross-section to its theoretical prediction. It is assumed that the top-quark-related CKM matrix elements obey the relation |V-td|, |V-ts| << |V-tb|. All the |f(LV)V(tb)|(2) determinations, extracted from individual ratios at = 7 and 8 TeV, are combined, resulting in |f(LV)V(tb)| = 1.02 +/- 0.04 (meas.) +/- 0.02 (theo.). All combined measurements are consistent with their corresponding Standard Model predictions.Peer reviewe

    The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

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    The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016-18 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6 fb1^{-1}, 46.9 fb1^{-1}, and 60.6 fb1^{-1} respectively of proton-proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and bb-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme

    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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    Search for dark matter in association with a Higgs boson decaying to bb-quarks in pppp collisions at s=13\sqrt s=13 TeV with the ATLAS detector

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    Charged-particle distributions at low transverse momentum in s=13\sqrt{s} = 13 TeV pppp interactions measured with the ATLAS detector at the LHC

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    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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