3,414 research outputs found

    Tunneling into Nonequilibrium Luttinger Liquid with Impurity

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    We evaluate tunneling rates into/from a voltage biased quantum wire containing weak backscattering defect. Interacting electrons in such a wire form a true nonequilibrium state of the Luttinger liquid (LL). This state is created due to inelastic electron backscattering leading to the emission of nonequilibrium plasmons with typical frequency ωU\hbar \omega \leq U. The tunneling rates are split into two edges. The tunneling exponent at the Fermi edge is positive and equals that of the equilibrium LL, while the exponent at the side edge EFUE_F-U is negative if Coulomb interaction is not too strong.Comment: 4+ pages, 5 figure

    Population-level approaches to universal health coverage in resource-poor settings: Lessons from tobacco control policy in Vietnam

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    Population-based health promotion and disease prevention approaches are essential elements in achieving universal health coverage; yet they frequently do not appear on national policy agendas. This paper suggests that resource-poor countries should take greater advantage of such approaches to reach all segments of the population to positively affect health outcomes and equity, especially considering the epidemic of chronic non-communicable diseases and associated modifiable risk factors. Tobacco control policy development and implementation in Vietnam provides a case study to discuss opportunities and challenges associated with such strategies

    The development of Tobacco Harm Prevention Law in Vietnam: stakeholder tensions over tobacco control legislation in a state owned industry

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    Background: Building on its National Tobacco Control Policy initiated in 2000, Vietnam is currently considering introducing a comprehensive law to strengthen the implementation of tobacco control policy. This study analyses the positions of key stakeholders in the development of tobacco control legislation in the context of a largely state-owned industry, and discusses their implications for the policy process

    How Perceived Privacy Risk Determines People’s Willingness to Use Online Fashion Technologies

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    The subjective perception of Risk, Security, and Privacy in using online platforms and technologies determines to a large extent customers’ behaviours on these platforms. Accordingly, in this applied research project we have empirically explored how procedural anonymity and privacy influence customers’ willingness to use an online fitting application for fashion. Moreover, we have developed a psychometric tool that captures the psycholog ical variables (e.g., trust, perceived privacy risk, perceived privacy control, and online self-disclosure behaviour) of using online fashion technology. Furthermore, we will report the psychological factors that predict customers’ willingness to use online technology for fashion (e.g., online fitting application)

    Quasi one dimensional transport in individual electrospun composite nanofibers

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    We present results of transport measurements of individual suspended electrospun nanofibers Poly(methyl methacrylate)-multiwalled carbon nanotubes. The nanofiber is comprised of highly aligned consecutive multiwalled carbon nanotubes. We have confirmed that at the range temperature from room temperature down to ∼60 K, the conductance behaves as power-law of temperature with an exponent of α ∼ 2.9−10.2. The current also behaves as power law of voltage with an exponent of β ∼ 2.3−8.6. The power-law behavior is a footprint for one dimensional transport. The possible models of this confined system are discussed. Using the model of Luttinger liquid states in series, we calculated the exponent for tunneling into the bulk of a single multiwalled carbon nanotube αbulk ∼ 0.06 which agrees with theoretical predictions

    EPIC 219217635: A Doubly Eclipsing Quadruple System Containing an Evolved Binary

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    We have discovered a doubly eclipsing, bound, quadruple star system in the field of K2 Campaign 7. EPIC 219217635 is a stellar image with Kp=12.7Kp = 12.7 that contains an eclipsing binary (`EB') with PA=3.59470P_A = 3.59470 d and a second EB with PB=0.61825P_B = 0.61825 d. We have obtained followup radial-velocity (`RV') spectroscopy observations, adaptive optics imaging, as well as ground-based photometric observations. From our analysis of all the observations, we derive good estimates for a number of the system parameters. We conclude that (1) both binaries are bound in a quadruple star system; (2) a linear trend to the RV curve of binary A is found over a 2-year interval, corresponding to an acceleration, γ˙=0.0024±0.0007\dot \gamma = 0.0024 \pm 0.0007 cm s2^{-2}; (3) small irregular variations are seen in the eclipse-timing variations (`ETVs') detected over the same interval; (4) the orbital separation of the quadruple system is probably in the range of 8-25 AU; and (5) the orbital planes of the two binaries must be inclined with respect to each other by at least 25^\circ. In addition, we find that binary B is evolved, and the cooler and currently less massive star has transferred much of its envelope to the currently more massive star. We have also demonstrated that the system is sufficiently bright that the eclipses can be followed using small ground-based telescopes, and that this system may be profitably studied over the next decade when the outer orbit of the quadruple is expected to manifest itself in the ETV and/or RV curves.Comment: Accepted for publication in MNRA

    Friends of Hot Jupiters II: No Correspondence Between Hot-Jupiter Spin-Orbit Misalignment and the Incidence of Directly Imaged Stellar Companions

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    Multi-star systems are common, yet little is known about a stellar companion's influence on the formation and evolution of planetary systems. For instance, stellar companions may have facilitated the inward migration of hot Jupiters towards to their present day positions. Many observed short period gas giant planets also have orbits that are misaligned with respect to their star's spin axis, which has also been attributed to the presence of a massive outer companion on a non-coplanar orbit. We present the results of a multi-band direct imaging survey using Keck NIRC2 to measure the fraction of short period gas giant planets found in multi-star systems. Over three years, we completed a survey of 50 targets ("Friends of Hot Jupiters") with 27 targets showing some signature of multi-body interaction (misaligned or eccentric orbits) and 23 targets in a control sample (well-aligned and circular orbits). We report the masses, projected separations, and confirmed common proper motion for the 19 stellar companions found around 17 stars. Correcting for survey incompleteness, we report companion fractions of 48%±9%48\%\pm9\%, 47%±12%47\%\pm12\%, and 51%±13%51\%\pm13\% in our total, misaligned/eccentric, and control samples, respectively. This total stellar companion fraction is 2.8σ2.8\,\sigma larger than the fraction of field stars with companions approximately 50200050-2000\,AU. We observe no correlation between misaligned/eccentric hot Jupiter systems and the incidence of stellar companions. Combining this result with our previous radial velocity survey, we determine that 72%±16%72\% \pm 16\% of hot Jupiters are part of multi-planet and/or multi-star systems.Comment: typos and references updated; 25 pages, 7 figures and 10 tables, accepted for publication in Ap

    Monte Carlo studies of the Ising square lattice with competing interactions

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    We use improved Monte-Carlo algorithms to study the antiferromagnetic 2D-Ising model with competing interactions J1J_1 on nearest neighbour and J2J_2 on next-nearest neighbour bonds. The finite-temperature phase diagram is divided by a critical point at J2=J1/2J_2 = J_1/2 where the groundstate is highly degenerate. To analyse the phase boundaries we look at the specific heat and the energy distribution for various ratios of J2/J1J_2/J_1. We find a first order transition for small J2>J1/2J_2 > J_1/2 and the transition temperature suppressed to TC=0T_C=0 at the critical point.Comment: 4 pages, 4 figures, accepted for publication in the proceedings of the conference on Highly Frustrated Magnets 2008 in Braunschwei
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