8,088 research outputs found

    Quantum oscillations in the parent pnictide BaFe2_2As2_2 : itinerant electrons in the reconstructed state

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    We report quantum oscillation measurements that enable the direct observation of the Fermi surface of the low temperature ground state of \ba122. From these measurements we characterize the low energy excitations, revealing that the Fermi surface is reconstructed in the antiferromagnetic state, but leaving itinerant electrons in its wake. The present measurements are consistent with a conventional band folding picture of the antiferromagnetic ground state, placing important limits on the topology and size of the Fermi surface.Comment: 5 pages, 3 figure

    Investigating five key predictive text entry with combined distance and keystroke modelling

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    This paper investigates text entry on mobile devices using only five-keys. Primarily to support text entry on smaller devices than mobile phones, this method can also be used to maximise screen space on mobile phones. Reported combined Fitt's law and keystroke modelling predicts similar performance with bigram prediction using a five-key keypad as is currently achieved on standard mobile phones using unigram prediction. User studies reported here show similar user performance on five-key pads as found elsewhere for novice nine-key pad users

    Modeling the Optical-X-ray Accretion Lag in LMC X-3: Insights Into Black-Hole Accretion Physics

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    The X-ray persistence and characteristically soft spectrum of the black hole X-ray binary LMC X-3 make this source a touchstone for penetrating studies of accretion physics. We analyze a rich, 10-year collection of optical/infrared (OIR) time-series data in conjunction with all available contemporaneous X-ray data collected by the ASM and PCA detectors aboard the Rossi X-ray Timing Explorer. A cross-correlation analysis reveals an X-ray lag of ~2 weeks. Motivated by this result, we develop a model that reproduces the complex OIR light curves of LMC X-3. The model is comprised of three components of emission: stellar light; accretion luminosity from the outer disk inferred from the time-lagged X-ray emission; and light from the X-ray-heated star and outer disk. Using the model, we filter a strong noise component out of the ellipsoidal light curves and derive an improved orbital period for the system. Concerning accretion physics, we find that the local viscous timescale in the disk increases with the local mass accretion rate; this in turn implies that the viscosity parameter alpha decreases with increasing luminosity. Finally, we find that X-ray heating is a strong function of X-ray luminosity below ~50% of the Eddington limit, while above this limit X-ray heating is heavily suppressed. We ascribe this behavior to the strong dependence of the flaring in the disk upon X-ray luminosity, concluding that for luminosities above ~50% of Eddington, the star lies fully in the shadow of the disk.Comment: Accepted in ApJ (12 pages long in emulateapj format

    Pharmaceutical companies’ documented and online privacy practices: Development of an index measure and initial test

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    Consumers have begun to take a more proactive approach to their healthcare by accessing pharmaceutical companies Websites to obtain health and drug information. In exchange for these benefits, companies require consumers to voluntarily disclose information. However, research has shown that consumers continue to be concerned about how their information is managed, used, and distributed by companies, especially if accessed via the Web. To date, there has been limited empirical research to examine the actual online practices of companies when it comes to privacy, especially those of pharmaceutical companies. Using the Delphi expert panel process, we identified the components of a hierarchical benchmarking index to examine the documented and actual online practices of 100 Website registrations with pharmaceutical companies. In this paper, we outline the development of an index to measure the personal information privacy violations of pharmaceutical companies using hierarchical linear technique. Second, we provided empirical evidence regarding the magnitude of voluntary adherence to the Fair Information Practices (FIPs) by pharmaceutical companies based upon the personal information privacy violations. Our results revealed that companies with headquarters in Europe had fewer personal information privacy violations than those in the US. Moreover, our results indicate that fewer personal information privacy violations occur for chronic conditions than for non-chronic conditions, as well as fewer violations occur with Website registrations for updates than for discounts. Finally, both Europe and UK demonstrated more overall adherence to the FIPs than the US and Asia. This suggests that self-regulation may not be sufficien

    The Mass of the Black Hole in LMC X-3

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    We analyze a large set of new and archival photometric and spectroscopic observations of LMC X-3 to arrive at a self-consistent dynamical model for the system. Using echelle spectra obtained with the MIKE instrument on the 6.5m Magellan Clay telescope and the UVES instrument on the second 8.2m Very Large Telescope we find a velocity semiamplitude for the secondary star of K2=241.1±6.2K_2=241.1\pm 6.2 km s1^{-1}, where the uncertainty includes an estimate of the systematic error caused by X-ray heating. Using the spectra, we also find a projected rotational velocity of Vrotsini=118.5±6.6V_{\rm rot}\sin i=118.5\pm 6.6 km s1^{-1}. From an analysis of archival BB and VV light curves as well as new BB and VV light curves from the SMARTS 1.3m telescope, we find an inclination of i=69.84±0.37i=69.84\pm 0.37^{\circ} for models that do not include X-ray heating and an inclination of i=69.24±0.72i=69.24\pm 0.72^{\circ} for models that incorporate X-ray heating. Adopting the latter inclination measurement, we find masses of 3.63±0.57M3.63\pm 0.57\,M_{\odot} and 6.98±0.56M6.98\pm 0.56\,M_{\odot} for the companion star and the black hole, respectively. We briefly compare our results with earlier work and discuss some of their implications.Comment: 31 pages, 15 figures, substantial revisions, ApJ, accepte

    Association of Osteoarthritis with Perfluorooctanoate and Perfluorooctane Sulfonate in NHANES 2003–2008

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    Background: Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent, synthetic industrial chemicals. Perfluorinated compounds are linked to health impacts that may be relevant to osteoarthritis, cartilage repair, and inflammatory responses. Objectives: We investigated whether PFOA and PFOS exposures are associated with prevalence of osteoarthritis, and whether associations differ between men and women. Methods: We used multiple logistic regression to estimate associations between serum PFOA and PFOS concentrations and self-reported diagnosis of osteoarthritis in persons 20–84 years of age who participated in NHANES during 2003–2008. We adjusted for potential confounders including age, income, and race/ethnicity. Effects by sex were estimated using stratified models and interaction terms. Results: Those in the highest exposure quartile had higher odds of osteoarthritis compared with those in the lowest quartile [odds ratio (OR) for PFOA = 1.55; 95% CI: 0.99, 2.43; OR for PFOS = 1.77; 95% CI: 1.05, 2.96]. When stratifying by sex, we found positive associations for women, but not men. Women in the highest quartiles of PFOA and PFOS exposure had higher odds of osteoarthritis compared with those in the lowest quartiles (OR for PFOA = 1.98; 95% CI: 1.24, 3.19 and OR for PFOS = 1.73; 95% CI: 0.97, 3.10). Conclusions: Higher concentrations of serum PFOA were associated with osteoarthritis in women, but not men. PFOS was also associated with osteoarthritis in women only, though effect estimates for women were not significant. More research is needed to clarify potential differences in susceptibility between women and men with regard to possible effects of these and other endocrine-disrupting chemicals

    Evaluation of a chiral cubane-based Schiff base ligand in asymmetric catalysis reactions

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    Recently, a novel chiral cubane-based Schiff base ligand was reported to yield modest enantioselectivity in the Henry reaction. To further explore the utility of this ligand in other asymmetric organic transformations, we evaluated its stereoselectivity in cyclopropanation and Michael addition reactions. Although there was no increase in stereocontrol, upon computational evaluation using both M06L and B3LYP calculations, it was revealed that a pseudo six-membered ring exists, through H-bonding of a cubyl hydrogen to the copper core. This decreases the steric bulk above the copper center and limits the asymmetric control with this ligand.The authors thank the Niagara University Academic Center for Integrated Science and the Rochester Academy of Science for their financial support. MLI would like to thank the Barbara S. Zimmer Memorial Research Award for financial aid. MLC gratefully acknowledges generous allocations of supercomputing time from the Australian National Computational Infrastructure, support from the Australian Research Council under its Centers of Excellence program, and an ARC Future Fellowship. RP would also like to thank Western New England University, College of Pharmacy for generous financial support

    Unmanned Multiple Exploratory Probe System (MEPS) for Mars observation. Volume 2: Calculations and derivations

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    This volume of the final report on the unmanned Multiple Exploratory Probe System (MEPS) details all calculations, derivations, and computer programs that support the information presented in the first volume

    Reporting of conflicts of interest from drug trials in Cochrane reviews:cross sectional study

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    Objectives To investigate the degree to which Cochrane reviews of drug interventions published in 2010 reported conflicts of interest from included trials and, among reviews that reported this information, where it was located in the review documents. Design Cross sectional study. Data sources Cochrane Database of Systematic Reviews. Selection criteria Systematic reviews of drug interventions published in 2010 in the Cochrane Database of Systematic Reviews, with review content classified as up to date in 2008 or later and with results from one or more randomised controlled trials. Results Of 151 included Cochrane reviews, 46 (30%, 95% confidence interval 24% to 38%) reported information on the funding sources of included trials, including 30 (20%, 14% to 27%) that reported information on trial funding for all included trials and 16 (11%, 7% to 17%) that reported for some, but not all, trials. Only 16 of the 151 Cochrane reviews (11%, 7% to 17%) provided any information on trial author-industry financial ties or trial author-industry employment. Information on trial funding and trial author-industry ties was reported in one to seven locations within each review, with no consistent reporting location observed. Conclusions Most Cochrane reviews of drug trials published in 2010 did not provide information on trial funding sources or trial author-industry financial ties or employment. When this information was reported, location of reporting was inconsistent across reviews
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