1,145 research outputs found

    Preasymptotic multiscaling in the phase-ordering dynamics of the kinetic Ising model

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    The evolution of the structure factor is studied during the phase-ordering dynamics of the kinetic Ising model with conserved order parameter. A preasymptotic multiscaling regime is found as in the solution of the Cahn-Hilliard-Cook equation, revealing that the late stage of phase-ordering is always approached through a crossover from multiscaling to standard scaling, independently from the nature of the microscopic dynamics.Comment: 11 pages, 3 figures, to be published in Europhys. Let

    Facilitating staff and student engagement with graduate attribute development, assessment and standards in business faculties

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    The project aimed to promote strategic change in advancing graduate attribute development in business education through staff and student engagement with learning and assessment processes that embed attribute development. This focus is of upmost importance as Australian business schools seek to obtain international accreditation, such as that of the Association to Advance Collegiate Schools of Business (AACSB) which requires each degree program specify learning goals and demonstrate a student's achievement of them. The participating institutions had all achieved initial AACSB accreditation and were involved in the maintenance of accreditation process. A social constructivist approach to graduate attributes was adopted, whereby assessment processes, criteria and standards were framed within an active engagement and participation of both students and educators, supplemented by using a pre-existing online assessment system. Outcomes included a perceived increase in student and staff awareness of graduate attributes. Self-assessment aided students in developing a better understanding of their attribute development, with the data suggesting they became more accurate in self-evaluation over subsequent assessment submissions. The project implementation facilitated the development of a community of practice between the four partner institutions which engaged in numerous productive discussions that heightened awareness and provided solutions around a range of issues..

    Development of an Electrostatic Precipitator to Remove Martian Atmospheric Dust from ISRU Gas Intakes During Planetary Exploration Missions

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    Manned exploration missions to Mars will need dependable in situ resource utilization (ISRU) for the production of oxygen and other commodities. One of these resources is the Martian atmosphere itself, which is composed of carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), oxygen (0.13%), carbon monoxide (0.07%), and water vapor (0.03%), as well as other trace gases. However, the Martian atmosphere also contains relatively large amounts of dust, uploaded by frequent dust devils and high Winds. To make this gas usable for oxygen extraction in specialized chambers requires the removal of most of the dust. An electrostatic precipitator (ESP) system is an obvious choice. But with an atmospheric pressure just one-hundredth of Earth's, electrical breakdown at low voltages makes the implementation of the electrostatic precipitator technology very challenging. Ion mobility, drag forces, dust particle charging, and migration velocity are also affected because the low gas pressure results in molecular mean free paths that are approximately one hundred times longer than those at Earth .atmospheric pressure. We report here on our efforts to develop this technology at the Kennedy Space Center, using gases with approximately the same composition as the Martian atmosphere in a vacuum chamber at 9 mbars, the atmospheric pressure on Mars. We also present I-V curves and large particle charging data for various versions of wire-cylinder and rod-cylinder geometry ESPs. Preliminary results suggest that use of an ESP for dust collection on Mars may be feasible, but further testing with Martian dust simulant is required

    NICMOS Imaging of Infrared-Luminous Galaxies

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    We present near-infrared images obtained with the HST NICMOS camera for a sample of 9 luminous (LIGs: L_IR (8-1000 microns) >~ 10^11 L_sun) and 15 ultra-luminous (ULIGS: L_IR >~ 10^12 L_sun) infrared galaxies. The sample includes representative systems classified as warm (f_25/f_60 > 0.2) and cold (f_25/f_60 <~ 0.2) based on the mid-infrared colors and systems with nuclear emission lines classified as HII (i.e. starburst), QSO, Seyfert and LINER. The morphologies of the sample galaxies are diverse and provide further support for the idea that they are created by the collision or interactions of spiral galaxies. Although no new nuclei are seen in the NICMOS images, the NICMOS images do reveal new spiral structures, bridges, and circumnuclear star clusters...Comment: LaTex, 27 pages with 14 gif and 4 jpg figures, AJ, in press, contour figures of the NICMOS images can be viewed at http://nedwww.ipac.caltech.edu/level5/Scoville/frames.htm

    Herschel-ATLAS: The angular correlation function of submillimetre galaxies at high and low redshift

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern ObservatoryWe present measurements of the angular correlation function of galaxies selected from the first field of the H-ATLAS survey. Careful removal of the background from galactic cirrus is essential, and currently dominates the uncertainty in our measurements. For our 250 μm-selected sample we detect no significant clustering, consistent with the expectation that the 250 μm-selected sources are mostly normal galaxies at z 1. For our 350 μm and 500 μm-selected samples we detect relatively strong clustering with correlation amplitudes A of 0.2 and 1.2 at 1', but with relatively large uncertainties. For samples which preferentially select high redshift galaxies at z~2–3 we detect significant strong clustering, leading to an estimate of r0 ~ 7–11 h-1 Mpc. The slope of our clustering measurements is very steep, δ ~ 2. The measurements are consistent with the idea that sub-mm sources consist of a low redshift population of normal galaxies and a high redshift population of highly clustered star-bursting galaxies.Peer reviewe

    Medicaid Expenditures on Psychotropic Medications for Children in the Child Welfare System

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    Abstract Objective: Children in the child welfare system are the most expensive child population to insure for their mental health needs. The objective of this article is to estimate the amount of Medicaid expenditures incurred from the purchase of psychotropic drugs ? the primary drivers of mental health expenditures ? for these children. Methods: We linked a subsample of children interviewed in the first nationally representative survey of children coming into contact with U.S. child welfare agencies, the National Survey of Child and Adolescent Well-Being (NSCAW), to their Medicaid claims files obtained from the Medicaid Analytic Extract. Our data consist of children living in 14 states, and Medicaid claims for 4 years, adjusted to 2010 dollars. We compared expenditures on psychotropic medications in the NSCAW sample to a propensity score-matched comparison sample obtained from Medicaid files. Results: Children surveyed in NSCAW had over thrice the odds of any psychotropic drug use than the comparison sample. Each maltreated child increased Medicaid expenditures by between 237and237 and 840 per year, relative to comparison children also receiving medications. Increased expenditures on antidepressants and amphetamine-like stimulants were the primary drivers of these increased expenditures. On average, an African American child in NSCAW received 399lessexpenditurethanawhitechild,controllingforbehavioralproblemsandotherchildandregionalcharacteristics.ChildrenscoringintheclinicalrangeoftheChildBehaviorChecklistreceived,onaverage,399 less expenditure than a white child, controlling for behavioral problems and other child and regional characteristics. Children scoring in the clinical range of the Child Behavior Checklist received, on average, 853 increased expenditure on psychotropic drugs. Conclusion: Each child with child welfare involvement is likely to incur upwards of $1482 in psychotropic medication expenditures throughout his or her enrollment in Medicaid. Medicaid agencies should focus their cost-containment strategies on antidepressants and amphetamine-type stimulants, and expand use of instruments such as the Child Behavior Checklist to identify high-cost children. Both of these strategies can assist Medicaid agencies to better predict and plan for these expenditures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98497/1/cap%2E2011%2E0135.pd

    A search for debris disks in the Herschel-ATLAS

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO)Aims. We aim to demonstrate that the Herschel-ATLAS (H-ATLAS) is suitable for a blind and unbiased survey for debris disks by identifying candidate debris disks associated with main sequence stars in the initial science demonstration field of the survey. We show that H-ATLAS reveals a population of far-infrared/sub-mm sources that are associated with stars or star-like objects on the SDSS main-sequence locus. We validate our approach by comparing the properties of the most likely candidate disks to those of the known population. Methods. We use a photometric selection technique to identify main sequence stars in the SDSS DR7 catalogue and a Bayesian Likelihood Ratio method to identify H-ATLAS catalogue sources associated with these main sequence stars. Following this photometric selection we apply distance cuts to identify the most likely candidate debris disks and rule out the presence of contaminating galaxies using UKIDSS LAS K-band images. Results. We identify 78 H-ATLAS sources associated with SDSS point sources on the main-sequence locus, of which two are the most likely debris disk candidates: H-ATLAS J090315.8 and H-ATLAS J090240.2. We show that they are plausible candidates by comparing their properties to the known population of debris disks. Our initial results indicate that bright debris disks are rare, with only 2 candidates identified in a search sample of 851 stars. We also show that H-ATLAS can derive useful upper limits for debris disks associated with Hipparcos stars in the field and outline the future prospects for our debris disk search programme.Peer reviewe

    Does Type of Tumor Histology Impact Survival among Patients with Stage IIIB/IV Non-Small Cell Lung Cancer Treated with First-Line Doublet Chemotherapy?

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    Chemotherapy regimens may have differential efficacy by histology in nonsmall cell lung cancer (NSCLC). We examined the impact of histology on survival of patients (N = 2,644) with stage IIIB/IV NSCLC who received first-line cisplatin/carboplatin plus gemcitabine (C/C+G) and cisplatin/carboplatin plus a taxane (C/C+T) identified retrospectively in the SEER cancer registry (1997–2002). Patients with squamous and nonsquamous cell carcinoma survived 8.5 months and 8.1 months, respectively (P = .018). No statistically significant difference was observed in survival between C/C+G and C/C+T in both histologies. Adjusting for clinical and demographic characteristics, the effect of treatment regimen on survival did not differ by histology (P for interaction = .257). There was no statistically significant difference in hazard of death by histology in both groups. These results contrast the predictive role of histology and improved survival outcomes observed for cisplatin-pemetrexed regimens in advanced nonsquamous NSCLC

    Increased HIV Incidence in Men Who Have Sex with Men Despite High Levels of ART-Induced Viral Suppression: Analysis of an Extensively Documented Epidemic

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    Background: There is interest in expanding ART to prevent HIV transmission, but in the group with the highest levels of ART use, men-who-have-sex-with-men (MSM), numbers of new infections diagnosed each year have not decreased as ART coverage has increased for reasons which remain unclear. Methods: We analysed data on the HIV-epidemic in MSM in the UK from a range of sources using an individual-based simulation model. Model runs using parameter sets found to result in good model fit were used to infer changes in HIV-incidence and risk behaviour. Results: HIV-incidence has increased (estimated mean incidence 0.30/100 person-years 1990–1997, 0.45/100 py 1998–2010), associated with a modest (26%) rise in condomless sex. We also explored counter-factual scenarios: had ART not been introduced, but the rise in condomless sex had still occurred, then incidence 2006–2010 was 68% higher; a policy of ART initiation in all diagnosed with HIV from 2001 resulted in 32% lower incidence; had levels of HIV testing been higher (68% tested/year instead of 25%) incidence was 25% lower; a combination of higher testing and ART at diagnosis resulted in 62% lower incidence; cessation of all condom use in 2000 resulted in a 424% increase in incidence. In 2010, we estimate that undiagnosed men, the majority in primary infection, accounted for 82% of new infections. Conclusion: A rise in HIV-incidence has occurred in MSM in the UK despite an only modest increase in levels of condomless sex and high coverage of ART. ART has almost certainly exerted a limiting effect on incidence. Much higher rates of HIV testing combined with initiation of ART at diagnosis would be likely to lead to substantial reductions in HIV incidence. Increased condom use should be promoted to avoid the erosion of the benefits of ART and to prevent other serious sexually transmitted infections
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