71,184 research outputs found

    Tests of the Standard Model in Neutron Beta Decay with Polarized Neutron and Electron and Unpolarized Proton

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    We analyse the electron--energy and angular distribution of the neutron beta decay with polarized neutron and electron and unpolarized proton, calculated in Phys. Rev. C 95, 055502 (2017) within the Standard Model (SM), by taking into account the contributions of interactions beyond the SM. After the absorption of vector and axial vector contributions by the axial coupling constant and Cabibbo-Kobayashi-Maskawa (CKM) matrix element (Bhattacharya et al., Phys. Rev. D 85, 054512 (2012) and so on) these are the contributions of scalar and tensor interactions only. The neutron lifetime, correlation coefficients and their averaged values, and asymmetries of the neutron beta decay with polarized neutron and electron are adapted to the analysis of experimental data on searches of contributions of interactions beyond the SM. Using the obtained results we propose some estimates of the values of the scalar and tensor coupling constants of interactions beyond the SM. We use the estimate of the Fierz interference term "b_F = - 0.0028 +/- 0.0026" by Hardy and Towner (Phys. Rev. C 91, 025501 (2015)), the neutron lifetime "tau_n = 880.2(1.0)s"(Particle Data Group, Chin. Phys. C 40, 100001 (2016)) and the experimental data "N_{\exp} = 0.067 +/- 0.011_{\rm stat.} +/- 0.004_{\rm syst.}" for the averaged value of the correlation coefficient of the neutron-electron spin-spin correlations, measured by Kozela et al. (Phys. Ref. C 85, 045501 (2012)). The contributions of G-odd correlations are calculated and found at the level of 10^{-5} in agreement with the results obtained by Gardner and Plaster (Phys. Rev. C 87, 065504 (2013)).Comment: 15 pages, 1 figur

    A review of the potential local mechanisms by which exercise improves functional outcomes in intermittent claudication

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    © 2016 Elsevier Inc. All rights reserved. Background Intermittent claudication (IC) is a common condition which is associated with significant quality of life limitation. National Institute for Health and Care Excellence guidelines recommend a group-based supervised exercise program as the primary treatment option for claudication, based on clinical and cost effectiveness. This review aims to assess the mechanisms by which exercise improves outcomes in patients with IC. Methods MEDLINE, EMBASE, and PubMed were searched using the search strategy "claudication" [AND] "exercise" [AND] "mechanisms." Searches were limited from 1947 to October 2014. Only full-text articles published in the English language in adults (over 18 years of age) were eligible for the review. Any trial involving a nonsupervised exercise program was excluded. Abstracts identified by the database search were interrogated for relevance and citations from the shortlisted papers were hand searched for relevant references. Results The search yielded a total of 112 studies, of which 42 were duplicates. Forty-seven of the remaining 70 were deemed appropriate for inclusion in the review. Exercise is the first-line treatment for IC. Supervised exercise programs improve walking distances, endothelial and mitochondrial function, muscle strength, and endurance. Furthermore, it leads to a generalized improvement in cardiovascular fitness and overall quality of life. Conclusions The mechanism by which exercise improves outcome in claudicants is complicated and multifactorial. Further research is required in this area to fully elucidate the precise and predominant mechanisms and to assess whether targeted exercise program modification maximizes mechanism efficacy and patient outcome

    A Systematic Review of the Uptake and Adherence Rates to Supervised Exercise Programs in Patients with Intermittent Claudication

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    Background Intermittent claudication (IC) is a common and debilitating symptom of peripheral arterial disease and is associated with a significant reduction in a sufferer's quality of life. Guidelines recommend a supervised exercise program (SEP) as the primary treatment option; however, anecdotally there is a low participation rate for exercise in this group of patients. We undertook a systematic review of the uptake and adherence rates to SEPs for individuals with IC. Methods The MEDLINE, Embase, and PubMed databases were searched up to January 2015 for terms related to supervised exercise in peripheral arterial disease. The review had 3 aims: first, to establish the rates of uptake to SEPs, second, the rates of adherence to programs, and finally to determine the reasons reported for poor uptake and adherence. Separate inclusion and/or exclusion criteria were applied in selecting reports for each aim of the review. Results Only 23 of the 53 potentially eligible articles for uptake analysis identified on literature searches reported any details of screened patients (n = 7,517) with only 24.2% of patients subsequently recruited to SEPs. Forty-five percent of screen failures had no reason for exclusion reported. Sixty-seven articles with 4,012 patients were included for analysis of SEP adherence. Overall, 75.1% of patients reportedly completed an SEP; however, only one article defined a minimal attendance required for SEP completion. Overall, 54.1% of incomplete adherence was due to patient withdrawal and no reason for incomplete adherence was reported for 16% of cases. Conclusions Reporting of SEP trials was poor with regard to the numbers of subjects screened and reasons for exclusions. Only approximately 1 in 3 screened IC patients was suitable for and willing to undertake SEP. Levels of adherence to SEPs and definitions of satisfactory adherence were also lacking in most the current literature. Current clinical guidelines based on this evidence base may not be applicable to most IC patients and changes to SEPs may be needed to encourage and/or retain participants

    Stages of health behavior change and factors associated with physical activity in patients with intermittent claudication

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    OBJECTIVE: To analyze, in people with intermittent claudication, the frequency of individuals who are in each of stages of health behavior change to practice physical activity, and analyze the association of these stages with the walking capacity. METHODS: We recruited 150 patients with intermittent claudication treated at a tertiary center, being included those > 30-year-old-individuals and who had ankle-arm index < 0.90. We obtained socio-demographic information, presence of comorbidities and cardiovascular risk factors and stages of health behavior change to practice physical activity through a questionnaire, they being pre-contemplation, contemplation, preparation, action and maintenance. Moreover, the walking capacity was measured in a treadmill test (Gardner protocol). RESULTS: Most individuals were in the maintenance stage (42.7%), however, when the stages of health behavior change were categorized into active (action and maintenance) and inactive (pre-contemplation, contemplation and preparation), 51.3% of the individuals were classified as inactive behavior. There was no association between stages of health behavior change, sociodemographic factors and cardiovascular risk factors. However, patients with intermittent claudication who had lower total walking distance were three times more likely to have inactive behavior. CONCLUSION: Most patients with intermittent claudication showed an inactive behavior and, in this population, lower walking capacity was associated with this behavior

    Predictors of walking capacity in peripheral arterial disease patients

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    OBJECTIVE: To estimate walking capacity in intermittent claudication patients through a prediction model based on clinical characteristics and the walking impairment questionnaire. METHODS: The sample included 133 intermittent claudication patients of both genders aged between 30 and 80 years. Data regarding clinical characteristics, the walking impairment questionnaire and treadmill walking test performance were obtained. Multiple regression modeling was conducted to predict claudication onset distance and total walking distance using clinical characteristics (age, height, mass, body mass index, ankle brachial index lower, gender, history of smoking and co-morbid conditions) and walking impairment questionnaire responses. Comparisons of claudication onset distance and total walking distance measured during treadmill tests and estimated by a regression equation were performed using paired t-tests. RESULTS: Co-morbid conditions (diabetes and coronary artery disease) and questions related to difficulty in walking short distances (walking indoors - such as around your house and walking 5 blocks) and at low speed (walking 1 block at average speed - usual pace) resulted in the development of new prediction models high significant for claudication onset distance and total walking distance (p0.05) were observed. CONCLUSION: The current study demonstrated that walking capacity can be adequately estimated based on co-morbid conditions and responses to the walking impairment questionnaire

    The 2-point angular correlation function of 20,000 galaxies to V<23.5 and I<22

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    The UH8K wide field camera of the CFHT was used to image 0.68 deg^2 of sky. From these images, ~20,000 galaxies were detected to completeness magnitudes V<23.5 and I<22.5. The angular correlation function of these galaxies is well represented by the parameterization omega(theta) = A_W*theta^-delta. The slope delta=-0.8 shows no significant variation over the range of magnitude. The amplitude A_W decreases with increasing magnitude in a way that is most compatible with a Lambda-CDM model (Omega_0 = 0.2, Lambda=0.8) with a hierarchical clustering evolution parameter epsilon>0. We infer a best-fit spatial correlation length of r_00= 5.85+/-0.5 h^-1 Mpc at z=0. The peak redshift of the survey (I<22.5) is estimated to be z_peak~0.58, using the blue-evolving luminosity function from the CFRS and the flat Lambda cosmology, and r_0(z_peak)=3.5+/-0.5 h^-1 Mpc. We also detect a significant difference in clustering amplitude for the red and blue galaxies, quantitatively measured by correlation lengths of r_00=5.3+/-0.5 h^-1 Mpc and r_00=1.9+/-0.9 h^-1 Mpc respectively, at z=0.Comment: 21 pages, 21 figures,accepted in Astronomy and Astrophysic

    The Oxford-Dartmouth Thirty Degree Survey II: Clustering of Bright Lyman Break Galaxies - Strong Luminosity Dependent Bias at z=4

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    We present measurements of the clustering properties of bright (L>LL>L_{*}) z\sim4 Lyman Break Galaxies (LBGs) selected from the Oxford-Dartmouth Thirty Degree Survey (ODT). We describe techniques used to select and evaluate our candidates and calculate the angular correlation function which we find best fitted by a power law, ω(θ)=Awθβ\omega(\theta)=A_{w}\theta^{-\beta} with Aw=15.4A_{w}=15.4 (with θ\theta in arcseconds), using a constrained slope of β=0.8\beta=0.8. Using a redshift distribution consistent with photometric models, we deproject this correlation function and find a comoving r0=11.41.9+1.7r_{0}=11.4_{-1.9}^{+1.7} h1001_{100}^{-1} Mpc in a Ωm=0.3\Omega_m=0.3 flat Λ\Lambda cosmology for iAB24.5i_{AB}\leq24.5. This corresponds to a linear bias value of b=8.12.6+2.0b=8.1_{-2.6}^{+2.0} (assuming σ8=0.9\sigma_{8}=0.9). These data show a significantly larger r0r_{0} and bb than previous studies at z4z\sim4. We interpret this as evidence that the brightest LBGs have a larger bias than fainter ones, indicating a strong luminosity dependence for the measured bias of an LBG sample. Comparing this against recent results in the literature at fainter (sub-LL_{*}) limiting magnitudes, and with simple models describing the relationship between LBGs and dark matter haloes, we discuss the implications on the implied environments and nature of LBGs. It seems that the brightest LBGs (in contrast with the majority sub-LL_{*} population), have clustering properties, and host dark matter halo masses, that are consistent with them being progenitors of the most massive galaxies today.Comment: Accepted for Publication in MNRAS. 15 Pages, 13 Figure

    Barriers and enablers to walking in individuals with intermittent claudication: a systematic review to conceptualize a relevant and patient-centered program

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    Background: Walking limitation in patients with peripheral arterial disease (PAD) and intermittent claudication (IC) contributes to poorer disease outcomes. Identifying and examining barriers to walking may be an important step in developing a comprehensive patient-centered self-management intervention to promote walking in this population. Aim: To systematically review the literature regarding barriers and enablers to walking exercise in individuals with IC. Methods: A systematic review was conducted utilizing integrative review methodology. Five electronic databases and the reference lists of relevant studies were searched. Findings were categorized into personal, walking activity related, and environmental barriers and enablers using a social cognitive framework. Results: Eighteen studies including quantitative (n = 12), qualitative (n = 5), and mixed method (n = 1) designs, and reporting data from a total of 4376 patients with IC, were included in the review. The most frequently reported barriers to engaging in walking were comorbid health concerns, walking induced pain, lack of knowledge (e.g. about the disease pathology and walking recommendations), and poor walking capacity. The most frequently reported enablers were cognitive coping strategies, good support systems, and receiving specific instructions to walk. Findings suggest additionally that wider behavioral and environmental obstacles should be addressed in a patient-centered self-management intervention. Conclusions: This review has identified multidimensional factors influencing walking in patients with IC. Within the social cognitive framework, these factors fall within patient level factors (e.g. comorbid health concerns), walking related factors (e.g. claudication pain), and environmental factors (e.g. support systems). These factors are worth considering when developing self-management interventions to increase walking in patients with IC. Systematic review registration CRD42018070418
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