1,287 research outputs found

    Inland dunes on the abandoned bed of Glacial Lake Chicago indicate eolian activity during the Pleistocene-Holocene transition, southwestern Michigan, USA

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    Inland dune fields have recently emerged as a source of data for reconstructing paleoenvironments and climate in the western Great Lakes region of North America during the Pleistocene-Holocene transition. We employ optically stimulated luminescence (OSL) methods, radiocarbon ages, soils, and landform relationships to determine the age of inland dunes in Ottawa County, Michigan. These dunes rest on the abandoned bed of Glacial Lake Chicago, which is thought to have been exposed after ~13.6 ka. OSL analyses from two inland dunes yield ages ranging from 13.3±1.1 to 11.6±0.9 ka (uncertainty = 2 σ). Fine sand in the parabolic dunes suggests deflation of exposed glaciolacustrine nearshore sand by northwesterly and westerly winds. These new data add to a growing number of studies that demonstrate widespread eolian activity in the western Great Lakes region during the Pleistocene-Holocene transition. OSL ages from dune fields in the western Great Lakes indicate peak eolian activity and dune stabilization occurred during or following the Younger Dryas and Preboreal events. Northwesterly and westerly winds suggest the limited effect of hypothesized easterly anticyclonic winds during the Pleistocene-Holocene transition. Rapidly changing climate and newly deglaciated surfaces provided an ideal environment for dune formation

    Evaluating the Liverpool Care Pathway for care of the terminally ill in rural Australia

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    © 2015, Springer-Verlag Berlin Heidelberg. Purpose: This study evaluates a pilot implementation of the Liverpool Care Pathway (LCP), a clinical tool used to guide the care of dying patients in the last days of life, on the end-of-life care for dying patients in three regions in rural Australia. Methods: The LCP was implemented at 13 participating sites: nine hospitals (general wards), one community-based palliative care service, and three in-hospital palliative care units. To evaluate the implementation of the LCP, 415 eligible patient records were examined: 223 pre-implementation and 192 post-implementation (116 on the LCP and 76 receiving usual care). The primary analysis compared all patients pre-implementation of the LCP versus all patients post-implementation. Results: Increases were found post-implementation for communication with other health professionals and with patients or family (pre-69 %, post-87 %; p ≤ 0.000), use of palliative medications (pre-87 %, post-98 %; p ≤ 0.000) and frequency of symptom assessments (pre-66 %, post-82 %; p ≤ 0.000). Fewer blood and radiological investigations were conducted and venous access devices used in the post-implementation groups than in the pre-implementation period. Conclusions: This study suggests that when rigorously implemented, the LCP improves important components of end-of-life care for dying patients and their families

    Treatment of Ion-Atom Collisions using a Partial-Wave Expansion of the Projectile Wavefunction

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    We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge scattering quantities. Here we show that such calculations are possible using modern high-performance computing. We demonstrate the utility of our method by examining elastic scattering of protons by hydrogen and helium atoms, problems familiar to undergraduate students of atomic scattering. Application to ionization of helium using partial-wave expansions of the projectile wavefunction, which has long been desirable in heavy-ion collision physics, is thus quite feasible

    Four-Body Model for Transfer Excitation

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    We present here a four-body model for transfer-excitation collisions, which we call the four-body transfer-excitation (4BTE) model. Each two-body interaction is explicitly included in the 4BTE model, allowing us to study the effects of individual two-body interactions. We apply our model to fully differential cross sections for proton+helium collisions, and study the effect of the incident projectile-atom interaction, the scattered projectile-ion interaction, the projectile-nuclear interaction, and electron correlation within the target atom

    Tax Policy and Economic Development: A Roundtable Assessment

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    Economic development continues to be a top policy issue for the state of Maine. Within the broad topic of economic development is the issue of tax policy, and the state continues to experiment with changes in traditional taxes, such as sales and income, as well as with newer approaches, such as Employment Tax Increment Financing. What works and what does not work? Can the state afford the potential loss of revenues associated with tax incentives? Who wins and who loses from these policies? To answer these questions, Maine Policy Review convened a panel of experts to review Maine’s record. Two represent state government and have been involved directly in the administration of tax incentives, Brian Mahany and Alan P. Brigham. They are joined by two policy analysts with expertise in economic development, Christopher Kit St. John and Charles Colgan. There is a surprising degree of consensus about the inevitability of tax incentives and the value of their judicious application. Yet, it also is clear that they are not the centerpiece of economic development policy, and their impacts on the equitable distribution of public funds must be monitored

    Spitzer observations of extragalactic H II regions - III. NGC 6822 and the hot star, H II region connection

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    Using the short-high module of the Infrared Spectrograph on the Spitzer Space Telescope, we have measured the [S IV] 10.51, [Ne II] 12.81, [Ne III] 15.56, and [S III] 18.71-micron emission lines in nine H II regions in the dwarf irregular galaxy NGC 6822. These lines arise from the dominant ionization states of the elements neon (Ne++^{++}, Ne+^+) and sulphur (S3+^{3+}, S++^{++}), thereby allowing an analysis of the neon to sulphur abundance ratio as well as the ionic abundance ratios Ne+^+/Ne++^{++} and S3+^{3+}/S++^{++}. By extending our studies of H II regions in M83 and M33 to the lower metallicity NGC 6822, we increase the reliability of the estimated Ne/S ratio. We find that the Ne/S ratio appears to be fairly universal, with not much variation about the ratio found for NGC 6822: the median (average) Ne/S ratio equals 11.6 (12.2±\pm0.8). This value is in contrast to Asplund et al.'s currently best estimated value for the Sun: Ne/S = 6.5. In addition, we continue to test the predicted ionizing spectral energy distributions (SEDs) from various stellar atmosphere models by comparing model nebulae computed with these SEDs as inputs to our observational data, changing just the stellar atmosphere model abundances. Here we employ a new grid of SEDs computed with different metallicities: Solar, 0.4 Solar, and 0.1 Solar. As expected, these changes to the SED show similar trends to those seen upon changing just the nebular gas metallicities in our plasma simulations: lower metallicity results in higher ionization. This trend agrees with the observations.Comment: 22 pages, 13 figures. To be published in MNRAS. reference added and typos fixed. arXiv admin note: text overlap with arXiv:0804.0828, which is paper II by Rubin et al. (2008

    Electron-Impact Ionization of Laser-Aligned Atoms -- Contributions from Both Natural and Unnatural-Parity States

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    Synopsis. The progress of experimental and theoretical measurements for (e,2e) ionization cross sections from laser-aligned atoms is presented here. It is found that both natural and unnatural parity contributions must be included in the models to emulate the experimental data

    First Evidence of Interference Effects in the Ionization of Nâ‚‚ Molecule

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    We will present an experimental and theoretical investigation of triple differential cross sections for electron- impact ionization of nitrogen molecules at intermediate energies. A discussion of interference effects contained in the theoretical and experimental interference factors will be presented
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