70 research outputs found

    The Distributional Impact of Statewide Property Tax Relief: the Michigan Case

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    This study uses data from a random survey of 2001 Michigan households to analyze the extent to which the Michigan ctreuit-breaker has been successful in reducing the income regressivity of the property tax and in changing relative property tax burdens. Because of its relatively extensive coverage, including renters as well as homeowners and the nonaged as well as the aged, the circuit-breaker has yielded a more equal distribution of income within Michigan. Its potential to change the distribution of income depends on the particular formula utilized, but redistributional effects have thus far been lamited because program participation has been positively correlated with income. To the extent that reductions in the price ofpublic services created by the circuit-breaker are perceived by households, the biggest stimulus appears to be in high property tax/high-income countiesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68848/2/10.1177_109114218301100201.pd

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Towards Jetography

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    As the LHC prepares to start taking data, this review is intended to provide a QCD theorist's understanding and views on jet finding at hadron colliders, including recent developments. My hope is that it will serve both as a primer for the newcomer to jets and as a quick reference for those with some experience of the subject. It is devoted to the questions of how one defines jets, how jets relate to partons, and to the emerging subject of how best to use jets at the LHC.Comment: 95 pages, 28 figures, an extended version of lectures given at the CTEQ/MCNET school, Debrecen, Hungary, August 2008; v2 includes additional discussion in several places, as well as other clarifications and additional references

    Genome-wide meta-analysis associates HLA-DQA1/DRB1 and LPA and lifestyle factors with human longevity

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    Genomic analysis of longevity offers the potential to illuminate the biology of human aging. Here, using genome-wide association meta-analysis of 606,059 parents' survival, we discover two regions associated with longevity (HLA-DQA1/DRB1 and LPA). We also validate previous suggestions that APOE, CHRNA3/5, CDKN2A/B, SH2B3 and FOXO3A influence longevity. Next we show that giving up smoking, educational attainment, openness to new experience and high-density lipoprotein (HDL) cholesterol levels are most positively genetically correlated with lifespan while susceptibility to coronary artery disease (CAD), cigarettes smoked per day, lung cancer, insulin resistance and body fat are most negatively correlated. We suggest that the effect of education on lifespan is principally mediated through smoking while the effect of obesity appears to act via CAD. Using instrumental variables, we suggest that an increase of one body mass index unit reduces lifespan by 7 months while 1 year of education adds 11 months to expected lifespan

    Study of Charm Fragmentation into D^{*\pm} Mesons in Deep-Inelastic Scattering at HERA

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    The process of charm quark fragmentation is studied using D±D^{*\pm} meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the D±D^{*\pm} meson in the event. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavour number scheme using the independent fragmentation of charm quarks to D±D^{*\pm} mesons.Comment: 33 pages, submitted to EPJ

    Search for excited leptons in pp collisions at √s=7 TeV

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    This is the pre-print version of the final published paper that is available from the link belowResults are presented of a search for compositeness in electrons and muons using a data sample of pp collisions at a center-of-mass energy √s=7 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 5.0 fb−15.0 fb−1. Excited leptons (ℓ⁎) are assumed to be produced via contact interactions in conjunction with a standard model lepton and to decay via ℓ⁎→ℓγ, yielding a final state with two energetic leptons and a photon. The number of events observed in data is consistent with that expected from the standard model. The 95% confidence upper limits for the cross section for the production and decay of excited electrons (muons), with masses ranging from 0.6 to 2 TeV, are 1.48 to 1.24 fb (1.31 to 1.11 fb). Excited leptons with masses below 1.9 TeV are excluded for the case where the contact interaction scale equals the excited lepton mass. The limits on the cross sections are the most stringent ones published to date

    Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

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    Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

    Spatial and seasonal patterns in freshwater ichthyofaunal communities of a tropical high Island in Fiji

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    We surveyed freshwater ichthyofaunal communities in streams of Vanua Levu, Fiji, under a range of land cover to assess differential, seasonal effects on fish abundance and diversity. We collected fish from 32 families, 19 genera and 87 species, representing approximately 50% of the known Fijian freshwater and estuarine fish fauna. Position in reach was the strongest overall factor influencing fish abundance and diversity, particularly in the larger, steeper catchments. However, fish communities exhibited strong seasonal specificity with over half (55%) of species observed in only one season. There were greater numbers of estuarine and marine migrants and fishes with poor swimming ability in the dry season, with more schooling species, large predators and fish that prefer muddy benthos in the wet. In the more pristine catchments of Kubulau District, higher species abundance and diversity were observed in the wet season and were associated with significantly greater flow, pH and dissolved oxygen. We observed the opposite pattern for fish diversity and abundance from the more degraded catchments of Macuata Province. These results suggest that the wet season is having a net positive effect on habitable space for fishes in Kubulau and a net negative effect in Macuata, as species may be lost due to increased runoff from heavily cleared and cultivated catchments. Integrated water resource management across the full range of habitats utilized by Fiji’s freshwater fishes is recommended in order to maintain species diversity and abundance
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