5,142 research outputs found

    TeV Strings and the Neutrino-Nucleon Cross Section at Ultra-high Energies

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    In scenarios with the fundamental unification scale at the TeV one expects string excitations of the standard model fields at accessible energies. We study the neutrino-nucleon cross section in these models. We show that duality of the scattering amplitude forces the existence of a tower of massive leptoquarks that mediate the process in the s-channel. Using the narrow-width approximation we find a sum rule for the production rate of resonances with different spin at each mass level. We show that these contributions can increase substantially the standard model neutrino-nucleon cross section, although seem insufficient in order to explain the cosmic ray events above the GZK cutoff energy.Comment: 10 pages, 1 figure, version to appear in PR

    Neutrino Observatories Can Characterize Cosmic Sources and Neutrino Properties

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    Neutrino telescopes that measure relative fluxes of ultrahigh-energy νe,νμ,ντ\nu_{e}, \nu_{\mu}, \nu_{\tau} can give information about the location and characteristics of sources, about neutrino mixing, and can test for neutrino instability and for departures from CPT invariance in the neutrino sector. We investigate consequences of neutrino mixing for the neutrino flux arriving at Earth, and consider how terrestrial measurements can characterize distant sources. We contrast mixtures that arise from neutrino oscillations with those signaling neutrino decays. We stress the importance of measuring νe,νμ,ντ\nu_{e}, \nu_{\mu}, \nu_{\tau} fluxes in neutrino observatories.Comment: 9 RevTeX pages, 4 figure

    Optical and Near Infrared Monitoring of the Black-Hole X-ray Binary GX 339-4 During 2002-2010

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    We present the optical/infra-red lightcurve (O/IR) of the black hole X-ray binary GX 339-4 collected at the SMARTS 1.3m telescope from 2002 to 2010. During this time the source has undergone numerous state transitions including hard-to-soft state transitions when we see large changes in the near-IR flux accompanied by modest changes in optical flux, and three rebrightening events in 2003, 2005 and 2007 after GX 339-4 transitioned from the soft state to the hard. All but one outburst show similar behavior in the X-ray hardness-intensity diagram. We show that the O/IR colors follow two distinct tracks that reflect either the hard or soft X-ray state of the source. Thus, either of these two X-ray states can be inferred from O/IR observations alone. From these correlations we have constructed spectral energy distributions of the soft and hard states. During the hard state, the near-IR data have the same spectral slope as simultaneous radio data when GX 339-4 was in a bright optical state, implying that the near-IR is dominated by a non-thermal source, most likely originating from jets. Non-thermal emission dominates the near-IR bands during the hard state at all but the faintest optical states, and the fraction of non-thermal emission increases with increasing optical brightness. The spectral slope of the optical bands indicate that a heated thermal source is present during both the soft and hard X-ray states, even when GX 339-4 is at its faintest optical state. We have conducted a timing analysis of the light curve for the hard and soft states and find no evidence of a characteristic timescale within the range of 4-230 days.Comment: Accepted for publication in AJ, Table 3 can be viewed at http://www.astro.yale.edu/buxton/GX339

    Exercise-based cardiac rehabilitation for adults with stable angina (review)

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    This is the final version of the article. Available from Cochrane Collaboration via the DOI in this record.BACKGROUND: A previous Cochrane review has shown that exercise-based cardiac rehabilitation (CR) can benefit myocardial infarction and post-revascularisation patients. However, the impact on stable angina remains unclear and guidance is inconsistent. Whilst recommended in the guidelines of American College of Cardiology/American Heart Association and the European Society of Cardiology, in the UK the National Institute for Health and Care Excellence (NICE) states that there is "no evidence to suggest that CR is clinically or cost-effective for managing stable angina". OBJECTIVES: To assess the effects of exercise-based CR compared to usual care for adults with stable angina. SEARCH METHODS: We updated searches from the previous Cochrane review 'Exercise-based cardiac rehabilitation for patients with coronary heart disease' by searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, DARE, CINAHL and Web of Science on 2 October 2017. We searched two trials registers, and performed reference checking and forward-citation searching of all primary studies and review articles, to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) with a follow-up period of at least six months, which compared structured exercise-based CR with usual care for people with stable angina. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the risk of bias and extracted data according to the Cochrane Handbook for Systematic Reviews of Interventions. Two review authors also independently assessed the quality of the evidence using GRADE principles and we presented this information in a 'Summary of findings' table. MAIN RESULTS: Seven studies (581 participants) met our inclusion criteria. Trials had an intervention length of 6 weeks to 12 months and follow-up length of 6 to 12 months. The comparison group in all trials was usual care (without any form of structured exercise training or advice) or a no-exercise comparator. The mean age of participants within the trials ranged from 50 to 66 years, the majority of participants being male (range: 74% to 100%). In terms of risk of bias, the majority of studies were unclear about their generation of the randomisation sequence and concealment processes. One study was at high risk of detection bias as it did not blind its participants or outcome assessors, and two studies had a high risk of attrition bias due to the numbers of participants lost to follow-up. Two trials were at high risk of outcome reporting bias. Given the high risk of bias, small number of trials and participants, and concerns about applicability, we downgraded our assessments of the quality of the evidence using the GRADE tool.Due to the very low-quality of the evidence base, we are uncertain about the effect of exercise-based CR on all-cause mortality (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.18 to 5.67; 195 participants; 3 studies; very low-quality evidence), acute myocardial infarction (RR 0.33, 95% CI 0.07 to 1.63; 254 participants; 3 studies; very low-quality evidence) and cardiovascular-related hospital admissions (RR 0.14, 95% CI 0.02 to 1.1; 101 participants; 1 study; very low-quality evidence). We found low-quality evidence that exercise-based CR may result in a small improvement in exercise capacity compared to control (standardised mean difference (SMD) 0.45, 95% CI 0.20 to 0.70; 267 participants; 5 studies, low-quality evidence). We were unable to draw conclusions about the impact of exercise-based CR on quality of life (angina frequency and emotional health-related quality-of-life score) and CR-related adverse events (e.g. skeletomuscular injury, cardiac arrhythmia), due to the very low quality of evidence. No data were reported on return to work. AUTHORS' CONCLUSIONS: Due to the small number of trials and their small size, potential risk of bias and concerns about imprecision and lack of applicability, we are uncertain of the effects of exercise-based CR compared to control on mortality, morbidity, cardiovascular hospital admissions, adverse events, return to work and health-related quality of life in people with stable angina. Low-quality evidence indicates that exercise-based CR may result in a small increase in exercise capacity compared to usual care. High-quality, well-reported randomised trials are needed to assess the benefits and harms of exercise-based CR for adults with stable angina. Such trials need to collect patient-relevant outcomes, including clinical events and health-related quality of life. They should also assess cost-effectiveness, and recruit participants that are reflective of the real-world population of people with angina.University of Exeter Medical School, UK. The Cochrane Heart Group US Satellite is supported by intramural support from the Northwestern University Feinberg School of Medicine and the Northwestern University Clinical and Translational Science (NUCATS) Institute (UL1TR000150)., USA. This project was supported by the National Institute for Health Research, via Cochrane Incentive funding to the Heart Group

    Wrist movement detector for ROS based control of the robotic hand

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    Robotic hands are used in a wide range of applications. They have many different shapes, constructions and capabilities. This work presents a new design of a robotic hand using tailor-made as well as widely available sensors and actuators. The information transferred between the sensor and actuators is processed using the Robot Operating System (ROS) topic mechanism. The robotic hand movement is remotely controlled by a movement detector mounted on the wrist of a human hand controller. Based on this simple hardware setup we demonstrate that the robotic hand can be remotely opened and closed thereby allowing to grasp objects flexibly

    Leptoquark production in ultrahigh-energy neutrino interactions revisited

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    The prospects for producing leptoquarks (LQs) in ultrahigh-energy (UHE) neutrino nucleon collisions are re-examined in the light of recent interpretations of HERA data in terms of leptoquark production. We update predictions for cross-sections for the production of first- and second-generation leptoquarks in UHE nu-N and nubar-N collisions including (i) recent experimental limits on masses and couplings from the LEP and TEVATRON colliders as well as rare processes, (ii) modern parton distributions, and (iii) radiative corrections to single leptoquark production. If the HERA events are due to an SU(2) doublet leptoquark which couples mainly to (e+,q) states, we argue that there are likely other LQ states which couple to neutrinos which are close in mass, due to constraints from precision electroweak measurements.Comment: 12 pages, LaTeX, 3 separate postscript figures. Added 1 reference plus discussion, updated another referenc

    Shifts in the architecture of the Nationwide Health Information Network

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    In the midst of a US $30 billion USD investment in the Nationwide Health Information Network (NwHIN) and electronic health records systems, a significant change in the architecture of the NwHIN is taking place. Prior to 2010, the focus of information exchange in the NwHIN was the Regional Health Information Organization (RHIO). Since 2010, the Office of the National Coordinator (ONC) has been sponsoring policies that promote an internet-like architecture that encourages point to-point information exchange and private health information exchange networks. The net effect of these activities is to undercut the limited business model for RHIOs, decreasing the likelihood of their success, while making the NwHIN dependent on nascent technologies for community level functions such as record locator services. These changes may impact the health of patients and communities. Independent, scientifically focused debate is needed on the wisdom of ONC's proposed changes in its strategy for the NwHIN

    Permutationally Invariant Networks for Enhanced Sampling (PINES): Discovery of Multi-Molecular and Solvent-Inclusive Collective Variables

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    The typically rugged nature of molecular free energy landscapes can frustrate efficient sampling of the thermodynamically relevant phase space due to the presence of high free energy barriers. Enhanced sampling techniques can improve phase space exploration by accelerating sampling along particular collective variables (CVs). A number of techniques exist for data-driven discovery of CVs parameterizing the important large scale motions of the system. A challenge to CV discovery is learning CVs invariant to symmetries of the molecular system, frequently rigid translation, rigid rotation, and permutational relabeling of identical particles. Of these, permutational invariance have proved a persistent challenge in frustrating the the data-driven discovery of multi-molecular CVs in systems of self-assembling particles and solvent-inclusive CVs for solvated systems. In this work, we integrate Permutation Invariant Vector (PIV) featurizations with autoencoding neural networks to learn nonlinear CVs invariant to translation, rotation, and permutation, and perform interleaved rounds of CV discovery and enhanced sampling to iteratively expand sampling of configurational phase space and obtain converged CVs and free energy landscapes. We demonstrate the Permutationally Invariant Network for Enhanced Sampling (PINES) approach in applications to the self-assembly of a 13-atom Argon cluster, association/dissociation of a NaCl ion pair in water, and hydrophobic collapse of a C45H92 n-pentatetracontane polymer chain. We make the approach freely available as a new module within the PLUMED2 enhanced sampling libraries
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