1,102 research outputs found

    Relativistic calculations of the lifetimes and hyperfine structure constants in 67^{67}Zn+^{+}

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    This work presents accurate {\it ab initio} determination of the magnetic dipole (M1) and electric quadrupole (E2) hyperfine structure constants for the ground and a few low-lying excited states in 67^{67}Zn+^{+}, which is one of the interesting systems in fundamental physics. The coupled-cluster (CC) theory within the relativistic framework has been used here in this calculations. Long standing demands for a relativistic and highly correlated calculations like CC can be able to resolve the disagreements among the lifetime estimations reported previously for a few low-lying states of Zn+^{+}. The role of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented.Comment: 9 pages, 1 figure. submitted to J. Phys. B Fast Trac

    Health Care Charges Associated With Physical Inactivity, Overweight, and Obesity

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    INTRODUCTION: Physical inactivity, overweight, and obesity are associated with increased morbidity and mortality. The objective of this study was to estimate the proportion of total health care charges associated with physical inactivity, overweight, and obesity among U.S. populations aged 40 years and older. METHODS: A predictive model of health care charges was developed using data from a cohort of 8000 health plan members aged 40 and older. Model cells were defined by physical activity status, body mass index, age, sex, smoking status, and selected chronic diseases. Total health care charges were estimated by multiplying the percentage of the population in each cell by the predicted charges per cell. Counterfactual estimates were computed by reclassifying all individuals as physically active and of normal weight while leaving other characteristics unchanged. Charges associated with physical inactivity, overweight, and obesity were computed as the difference between current risk profile total charges and counterfactual total charges. National population percentage estimates were derived from the National Health Interview Survey; those estimates were multiplied by the predicted charges per cell from the health plan analysis. RESULTS: Physical inactivity, overweight, and obesity were associated with 23% (95% confidence interval [CI], 10%–34%) of health plan health care charges and 27% (95% CI, 10%–37%) of national health care charges. Although charges associated with these risk factors were highest for the oldest group (aged 65 years and older) and for individuals with chronic conditions, nearly half of aggregate charges were generated from the group aged 40 to 64 years without chronic disease. CONCLUSION: Charges associated with physical inactivity, overweight, and obesity constitute a significant portion of total medical expenditures. The results underscore the importance of addressing these risk factors in all segments of the population

    Reactivity Initiated Accident Test Series RIA Scoping Test Quick Look Report

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    The Reactivity Initiated Accident Scoping Test (RIA-ST) was successfully completed August 30, 1978. The test was introductory to the RIA Series 1 tests and was designed to investigate and resolve several anticipated problem areas prior to performance of the first test of the series, Test RIA 1-1. The RIA Scoping Test, as performed, consisted of four separate single-rod experiment phases. The first three phases were performed with shrouded fuel rods of 5.8 wt.% enrichment. They were subjected to power bursts resulting in total fuel surface energies ranging from 205 to 261 cal/q at the axial peak elevation. The fourth phase consisted of a 20 wt.% enriched, shrouded fuel rod which was subjected to a power hurst that deposited a total radially averaged energy of 527 cal/g. The primary objectives of the Scoping Test were defined as follows: (1) Determine the applicability of extrapolating low-power steady state calorimetric measurements and self-powered neutron detector (SPND) output to determine fuel rod energy depositions during a power burst. (2) Determine the enerqy deposition failure threshold for unirradiated fuel rods at BWR hot-startup coolant conditions. (3) Determine the magnitudes of oossible pressure pulses resulting from rod failure. (4) Determine the sensitivity of the test instrumentation to high transient radiation exposures. In general, the energy deposition values for the Scoping Test derived from the SPND output were 25% higher than those obtained from the core ion chamber data. Determining which values are correct will require radiochemical analysis of the fuel rods which will take several months. At present, it apoears that the SPND derived energies are in error because of excellent agreement between the calculated and measured power calibration results and the agreement between the predicted failure threshold and that seen using the core ion chamber derived energies. Meeting the second objective was accomplished during the first three test phases by subjecting the fuel rods to energy depositions which bracketed the failure threshold. The failure threshold in terms of total pellet surface energy at the axial flux peak was found to be between 218 cal/g where no rod failure occurred and 256 cal/g where · rod failure did occur. The experiment predictions indicated that the failure threshold would be 262 cal/g at the pellet surface. Only the fourth experiment phase (527 cal/g) resulted in a pressure pulse upon rod failure. The best indication of source pressure was the reading from a 69 MPa EG&G pressure transducer at the flow shroud inlet. This pressure transducer indicated a pressure pulse upon rod failure of 28.2 MPa with a rise time of 1.6 ms. The source pressure was attenuated considerably outside the shroud region as indicated by pressure transducers in the upper plenum of the in-pile tube and in the flow bypass region. The maximum pressure indicated outside the flow shroud was 2.1 MPa. In general, instrumentation sensitivity to radiation was minimal. The most significant instrumentation problem during the power bursts was a false flowrate indication by the flow turbines. This problem is being examined. The Kaman and Bell & Howell pressure transducers showed the least sensitivity to radiation of the pressure measurement devices. The EG&G transducers were most sensitive. The locked linear variable differential transformer (LVDT) gave no indication of radiation sensitivity as its response during the burst was a straight line. The strain gages were very sensitive to radiation, indicating a strain increase of 70% with the second burst of RIA-ST-1. The Type S thermocouple did not exhibit significant radiation sensitivity. In addition, the RIA Scoping Test has provided data on the consequences of fuel rod failure during a RIA event at BWR hot startup conditions. Posttest examination of the fuel rods from the first two phases of the test revealed large quantities of UO{sub 2} fuel missing from the cladding. Fuel rod failures for energy depositions near the failure threshold in previous closed capsule tests without forced coolant flow resulted in only a slight amount of fuel loss

    Using a prisoner advisory group to develop diversity research in a maximum-security prison

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    This paper addresses groupwork processes with a group of prisoners advising a research project in a maximum-security prison in England. The research project (Appreciative Inquiry into the Diversity Strategy of HMP Wakefield. RES-000-22-3441) was funded by the Economic and Social Research Council (ESRC) and lasted 9 months. The research explored the experiences of prisoners in diverse minority groupings and the strategies of the prison to accommodate the complex needs of these groups. The Prisoner Advisory Group (PAG) was made up of representatives from Black and Minority Ethnic (BME) prisoners; older prisoners (over 60s); Disabled prisoners (with physical disabilities, learning difficulties; and mental health problems); Gay, Bi-sexual and Transgender prisoners; and prisoners affiliated to Faith groups. It met regularly during the research. The paper considers the forming norming and performing aspects of establishing an effective participant voice in a prison-based project. It considers the contribution of the PAG to developing a research strategy that engaged prisoners in the research. It reflects on the nature of ‘participative research’ in general and whether such research is possible within a high-security prison environment

    Anatomy and origin of authochthonous late Pleistocene forced regression deposits, east Coromandel inner shelf, New Zealand: implications for the development and definition of the regressive systems tract

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    High-resolution seismic reflection data from the east Coromandel coast, New Zealand, provide details of the sequence stratigraphy beneath an autochthonous, wave dominated inner shelf margin during the late Quaternary (0-140 ka). Since c. 1 Ma, the shelf has experienced limited subsidence and fluvial sediment input, producing a depositional regime characterised by extensive reworking of coastal and shelf sediments during glacio-eustatic sea-level fluctuations. It appears that only one complete fifth-order (c. 100 000 yr) depositional sequence is preserved beneath the inner shelf, the late Pleistocene Waihi Sequence, suggesting any earlier Quaternary sequences were mainly cannibalised into successively younger sequences. The predominantly Holocene-age Whangamata Sequence is also evident in seismic data and modern coastal deposits, and represents an incomplete depositional sequence in its early stages of formation. A prominent aspect of the sequence stratigraphy off parts of the east Coromandel coast is the presence of forced regressive deposits (FRDs) within the regressive systems tract (RST) of the late Pleistocene Waihi Sequence. The FRDs are interpreted to represent regressive barrier-shoreface sands that were sourced from erosion and onshore reworking of underlying Pleistocene sediments during the period of slow falling sea level from isotope stages 5 to 2 (c. 112-18 ka). The RST is volumetrically the most significant depositional component of the Waihi Sequence; the regressive deposits form a 15-20 m thick, sharp-based, tabular seismic unit that downsteps and progrades continuously across the inner shelf. The sequence boundary for the Waihi Sequence is placed at the most prominent, regionally correlative, and chronostratigraphically significant surface, namely an erosional unconformity characterised in many areas by large incised valleys that was generated above the RST. This unconformity is interpreted as a surface of maximum subaerial erosion generated during the last glacial lowstand (c. 18 ka). Although the base of the RST is associated with a prominent regressive surface of erosion, this is not used as the sequence boundary as it is highly diachronous and difficult to identify and correlate where FRDs are not developed. The previous highstand deposits are limited to subaerial barrier deposits preserved behind several modern Holocene barriers along the coast, while the transgressive systems tract is preserved locally as incised-valley fill deposits beneath the regressive surface of erosion at the base of the RST. Many documented late Pleistocene RSTs have been actively sourced from fluvial systems feeding the shelf and building basinward-thickening, often stacked wedges of FRDs, for which the name allochthonous FRDs is suggested. The Waihi Sequence RST is unusual in that it appears to have been sourced predominantly from reworking of underlying shelf sediments, and thus represents an autochthonous FRD. Autochthonous FRDs are also present on the Forster-Tuncurry shelf in southeast Australia, and may be a common feature in other shelf settings with low subsidence and low sediment supply rates, provided shelf gradients are not too steep, and an underlying source of unconsolidated shelf sediments is available to source FRDs. The preservation potential of such autochthonous FRDs in ancient deposits is probably low given that they are likely to be cannibalised during subsequent sea-level falls

    Large emissions from floodplain trees close the Amazon methane budget

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    Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources

    3D characterization of CdSe nanoparticles attached to carbon nanotubes

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    The crystallographic structure of CdSe nanoparticles attached to carbon nanotubes has been elucidated by means of high resolution transmission electron microscopy and high angle annular dark field scanning transmission electron microscopy tomography. CdSe rod-like nanoparticles, grown in solution together with carbon nanotubes, undergo a morphological transformation and become attached to the carbon surface. Electron tomography reveals that the nanoparticles are hexagonal-based with the (001) planes epitaxially matched to the outer graphene layer.Comment: 7 pages, 8 figure
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