964 research outputs found

    Galacto-forensic of LMC's orbital history as a probe for the dark matter potential in the outskirt of the Galaxy

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    The 3D observed velocities of the Large and Small Magellanic Clouds(LMC and SMC) provide an opportunity to probe the Galactic potential in the outskirt of the Galactic halo. Based on a canonical NFW model of the Galactic potential, Besla et al.(2007) reconstructed LMC and SMC's orbits and suggested that they are currently on their first perigalacticon passage about the Galaxy. Motivated by several recent revisions of the Sun's motion around the Galactic center, we re-examine the LMC's orbital history and show that it depends sensitively on the dark-matter's mass distribution beyond its present Galactic distance. We utilize results of numerical simulations to consider a range of possible structural and evolutionary models for the Galactic potentials. We find that within the theoretical and observational uncertainties, it is possible for the LMC to have had multiple perigalacticon passages on the Hubble time scale, especially if the Galactic circular velocity at the location of the Sun is greater than ∼228\sim 228km s−1^{-1}. Based on these models, a more accurate determination of the LMC's motion may be used to determine the dark matter distribution in the outskirt of the Galactic halo.Comment: 9 pages, 10 figures. Accepted for publication in Ap

    Partner Relationships and Injection Sharing Practices Among Rural Appalachian Women

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    Background—The role of relationships in initiating and maintaining women’s risk behaviors has been established. However, understanding factors that may underlie partner relationships and women’s risky drug use, particularly in rural contexts, is limited. This study is the first to examine the association between injecting partners and women’s risky injection practices as a function of relationship power perception. Methods—Female participants were recruited from three rural jails in the Appalachian region. Women were randomly selected, provided informed consent, and screened for study eligibility criteria. This cross-sectional analysis focuses on women who inject drugs (WWID) during the year before entering jail (n=199). Main findings—Approximately three-quarters (76%) reported having a recent main male sexual partner with a history of injection drug use (IDU). Although having a risky partner independently increased the likelihood of women reporting shared injection practices, perceptions of relationship power significantly moderated the effect on shared needle (AOR = 0.02 [0.003, 0.23]; p = .001) and shared works (AOR = 0.17 [0.03, 0.95]; p = .04) use. Conclusions—This interaction indicated that for WWID with a recent injecting male partner, greater perception of relationship power was associated with a decreased likelihood of shared injection practices. Implications for clinical assessment and intervention are discussed

    Recent Decisions

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    ACT OF STATE--Act of State Doctrine Not a Bar to Adjudication of a Counterclaim Robert M. Erickson ========================== ADMIRALTY--Ship Mortgage Act of 1920--Deficiency Judgment against Mortgagor in Personam Not Precluded by State Law when Vessels were Sold at Public Foreclosure Auction without Prior Appraisal Jack F. Stringham, II =========================== ALIENS--Immigration and Naturalization--Restriction of Commuter Aliens\u27 Access to Domestic Employment by Attorney General is Abuse of Discretion Alan Marchisotto ================= EXTRADITION--Principle of Specialty--Specialty does not Preclude Prosecution for Similar Offense when Asylum Nation Would Not Consider it a Breach of Faith Attorney General of the United States, 462 F.2d 475 (2d Cir. 1972),petition for cert. filed, 41 U.S.L.W. 3114 (U.S. Aug. 26, 1972) (No.332). James T. Campbell ========================= JURISDICTION--Forum Selection Clauses--United States Courts will Enforce Forum Selection Clauses in International Towage Contracts Absent Exceptional Circumstances Ralph C. Oser ======================== TAXATION--Foreign Tax Credit--Foreign Income Tax Credit Under Section 901 Allowable Only for Taxes Imposed on Net Gain or Profit David A. Boillo

    Constraints on Gamma-ray Emission from the Galactic Plane at 300 TeV

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    We describe a new search for diffuse ultrahigh energy gamma-ray emission associated with molecular clouds in the galactic disk. The Chicago Air Shower Array (CASA), operating in coincidence with the Michigan muon array (MIA), has recorded over 2.2 x 10^{9} air showers from April 4, 1990 to October 7, 1995. We search for gamma rays based upon the muon content of air showers arriving from the direction of the galactic plane. We find no significant evidence for diffuse gamma-ray emission, and we set an upper limit on the ratio of gamma rays to normal hadronic cosmic rays at less than 2.4 x 10^{-5} at 310 TeV (90% confidence limit) from the galactic plane region: (50 degrees < l < 200 degrees); -5 degrees < b < 5 degrees). This limit places a strong constraint on models for emission from molecular clouds in the galaxy. We rule out significant spectral hardening in the outer galaxy, and conclude that emission from the plane at these energies is likely to be dominated by the decay of neutral pions resulting from cosmic rays interactions with passive target gas molecules.Comment: Astrophysical Journal, submitted, 11 pages, AASTeX Latex, 3 Postscript figure

    Constraints on the relationship between stellar mass and halo mass at low and high redshift

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    We use a statistical approach to determine the relationship between the stellar masses of galaxies and the masses of the dark matter halos in which they reside. We obtain a parameterized stellar-to-halo mass (SHM) relation by populating halos and subhalos in an N-body simulation with galaxies and requiring that the observed stellar mass function be reproduced. We find good agreement with constraints from galaxy-galaxy lensing and predictions of semi-analytic models. Using this mapping, and the positions of the halos and subhalos obtained from the simulation, we find that our model predictions for the galaxy two-point correlation function (CF) as a function of stellar mass are in excellent agreement with the observed clustering properties in the SDSS at z=0. We show that the clustering data do not provide additional strong constraints on the SHM function and conclude that our model can therefore predict clustering as a function of stellar mass. We compute the conditional mass function, which yields the average number of galaxies with stellar masses in the range [m, m+dm] that reside in a halo of mass M. We study the redshift dependence of the SHM relation and show that, for low mass halos, the SHM ratio is lower at higher redshift. The derived SHM relation is used to predict the stellar mass dependent galaxy CF and bias at high redshift. Our model predicts that not only are massive galaxies more biased than low mass ones at all redshifts, but the bias increases more rapidly with increasing redshift for massive galaxies than for low mass ones. We present convenient fitting functions for the SHM relation as a function of redshift, the conditional mass function, and the bias as a function of stellar mass and redshift.Comment: 21 pages, 17 figures, discussion enlarged, one more figure, updated references, accepted for publication in Ap

    Increasing Employee Awareness of the Signs and Symptoms of Heart Attack and the Need to Use 911 in a State Health Department

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    INTRODUCTION: Early recognition of the signs and symptoms of a heart attack can lead to reduced morbidity and mortality. METHODS: A workplace intervention was conducted among 523 Montana state health department employees in 2003 to increase awareness of the signs and symptoms of heart attack and the need to use 911. All employees received an Act in Time to Heart Attack Signs brochure and wallet card with their paychecks. Act in Time posters were placed in key workplace areas. A weekly e-mail message, including a contest entry opportunity addressing the signs and symptoms of heart attack, was sent to all employees. Baseline and follow-up telephone surveys were conducted to evaluate intervention effectiveness. RESULTS: Awareness of heart attack signs and symptoms and the need to call 911 increased significantly among employees from baseline to follow-up: pain or discomfort in the jaw, neck, or back (awareness increased from 69% to 91%); feeling weak, light-headed, or faint (awareness increased from 79% to 89%); call 911 if someone is having a heart attack or stroke (awareness increased from 84% to 90%). Awareness of chest pain, pain or discomfort in the arms or shoulders, and shortness of breath were more than 90% at baseline and did not increase significantly at follow-up. At baseline, 69% of respondents correctly reported five or more of the signs and symptoms of heart attack; 89% reported correctly at follow-up. CONCLUSION: This low-cost workplace intervention increased awareness of the signs and symptoms of heart attack and the need to call 911
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