458 research outputs found

    High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

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    Hybrid acoustic-RF systems offer excellent ranging accuracy, yet they typically come at a power consumption that is too high to meet the energy constraints of mobile IoT nodes. We combine pulse compression and synchronized wake-ups to achieve a ranging solution that limits the active time of the nodes to 1 ms. Hence, an ultra low-power consumption of 9.015 µW for a single measurement is achieved. The operation time is estimated on 8.5 years on a CR2032 coin cell battery at a 1 Hz update rate, which is over 250 times larger than state-of-the-art RF-based positioning systems. Measurements based on a proof-of-concept hardware platform show median distance error values below 10 cm. Both simulations and measurements demonstrate that the accuracy is reduced at low signal-to-noise ratios and when reflections occur. We introduce three methods that enhance the distance measurements at a low extra processing power cost. Hence, we validate in realistic environments that the centimeter accuracy can be obtained within the energy budget of mobile devices and IoT nodes. The proposed hybrid signal ranging system can be extended to perform accurate, low-power indoor positioning

    Acculturation and Bicultural Efficacy Effects on Chinese American Immigrants’ Diabetes and Health Management

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    The primary goal of this study was to examine effects of bicultural efficacy, or perceived confidence in dealing with bicultural acculturation stressors, on type 2 diabetes management and health for first-generation, Cantonese-speaking, Chinese American immigrants (N=162) recruited for a larger community-based diabetes intervention study (Chesla et al., 2013). The current study also tested whether a new Bicultural Efficacy in Health Management (BEFF-HM) scale is a more robust predictor of diabetes and health outcomes than proxy (years in the U.S.) and general acculturation measures. Hierarchical regression analyses of cross-sectional data revealed that high BEFF-HM was significantly related to positive outcomes on five of six diabetes and health measures as hypothesized after accounting for participant characteristics, proxy and general acculturation measures, and social support. Proxy and general acculturation measures failed to predict any study outcome supporting our secondary hypothesis that BEFF-HM is a better predictor of Chinese American immigrants’ diabetes and health management. An immigrant-focused research approach advances understanding of acculturation and bicultural efficacy effects on health by identifying key acculturation domains for study

    The Relationship Between Diabetes Distress and Clinical Depression With Glycemic Control Among Patients With Type 2 Diabetes

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    ObjectiveTo clarify previous findings that diabetes distress is related to glycemic control and self-management whereas measures of depression are not, using both binary and continuous measures of depression.Research design and methodsFour hundred and sixty-three type 2 patients completed measures of diabetes distress (Diabetes Distress Scale [DDS]) and clinical depression (Patient Health Questionnaire 8 [PHQ8]). PHQ8 was employed as either a binary (>or=10) or continuous variable. Dependent variables were A1C, diet, physical activity (PA), and medication adherence (MA).ResultsThe inclusion of a binary or continuous PHQ8 score yielded no differences in any equation. DDS was significantly associated with A1C and PA, whereas PHQ8 was not; both DDS and PHQ8 were significantly and independently associated with diet and MA.ConclusionsThe lack of association between depression and glycemic control is not due to the use of a binary measure of depression. Findings further clarify the significant association between distress and A1C

    Self-Efficacy, Problem Solving, and Social-Environmental Support Are Associated With Diabetes Self-Management Behaviors

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    OBJECTIVE — To evaluate associations between psychosocial and social-environmental variables and diabetes self-management, and diabetes control. RESEARCH DESIGN AND METHODS — Baseline data from a type 2 diabetes self-management randomized trial with 463 adults having elevated BMI (M 34.8 kg/m2) were used to investigate relations among demographic, psychosocial, and social-environmental variables; dietary, exercise, and medication-taking behaviors; and biologic outcomes. RESULTS — Self-efficacy, problem solving, and social-environmental support were indepen-dently associated with diet and exercise, increasing the variance accounted for by 23 and 19%, respectively. Only diet contributed to explained variance in BMI ( 0.17, P 0.0003) and self-rated health status ( 0.25, P 0.0001); and only medication-taking behaviors contrib-uted to lipid ratio (total–to–HDL) (0.20, P 0.0001) and A1C (0.21, P 0.0001). CONCLUSIONS — Interventions should focus on enhancing self-efficacy, problem solving, and social-environmental support to improve self-management of diabetes. Diabetes Care 33:751–753, 2010 D iabetes management requires coor-dination between the patient andthe primary care team. Given the lifestyle changes required for self-management success, patient, social, and environmental factors, including health care (1) and community support (2), are increasingly recognized as important. Un-derstanding relations among demo-graphic, psychosocial, and social-environmental variables, and multiple health risk behaviors is critical to devel-oping interventions that will sustain health behavior changes. RESEARCH DESIGN AND METHODS — Baseline data were col-lected as part of a patient randomized trial to evaluate the impact of an interactive, multimedia diabetes self-management program relative to “enhanced ” usual car

    A multilevel approach to youth physical activity research.

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    A multilevel approach to youth physical activity research. Exerc. Sport Sci. Rev., Vol. 32, No. 3, pp. 95-99, 2004. Social environment factors are hypothesized to interact with individual-level factors to influence youth physical activity. Multilevel analytic approaches are ideal for examining the influence of the social environment on youth physical activity as they allow examination of research questions across multiple contexts and levels (e.g., individual, family, and neighborhood levels)

    Interacting with information and robotics systems

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    The aim of this paper is to present the results obtained during the project 131-CEEX/2006, INTEROB: Interacting by Gestures with Information and Robotics Systems for the time frame 2006-2008. The project focused on natural interaction using gesture recognition technology applied in various applications such as: virtual environments, augmented reality, collaborative working and interaction with robotics systems

    Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-

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    We report the first observation of the baryonic flavor-changing neutral current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}. We also report the first measurement of the differential branching ratio of B_s -> phi mu+ mu- using 49 signal events. In addition, we report branching ratios for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let

    Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

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    The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure

    Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

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    We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |\eta| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of \eta-\phi space; toward, away, and transverse, where \phi is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.

    Search for a Higgs Boson Produced in Association with a W Boson in pbar-p Collisions at sqrt{s} = 1.96 TeV

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    We present a search for a standard model Higgs boson produced in association with a W boson using 2.7 1/fb of integrated luminosity of pbar-p collision data taken at sqrt{s} = 1.96 TeV. Limits on the Higgs boson production rate are obtained for masses between 100 GeV and 150 GeV. Through the use of multivariate techniques, the analysis achieves an observed (expected) 95% confidence level upper limit of 5.6 (4.8) times the theoretically expected production cross section for a standard model Higgs boson with a mass of 115 GeV.Comment: submitted to Phys. Rev. Let
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