2,042 research outputs found

    Snatch trajectory of elite level girevoy (Kettlebell) sport athletes and its implications to strength and conditioning coaching

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    Girevoy sport (GS) has developed only recently in the West, resulting in a paucity of English scientific literature available. The aim was to document kettlebell trajectory of GS athletes performing the kettlebell snatch. Four elite GS athletes (age = 29-47 years, body mass = 68.3-108.1 kg, height 1.72-1.89 m) completed one set of 16 repetitions with a 32.1 kg kettlebell. Trajectory was captured with the VICON motion analysis system (250 Hz) and analysed with VICON Nexus (1.7.1). The kettlebell followed a ‘C’ shape trajectory in the sagittal plane. Mean peak velocity in the upwards phase was 4.03 ± 0.20 m s –1, compared to 3.70 ± 0.30 m s–1 during the downwards phase, and mean radial error across the sagittal and frontal planes was 0.022 ± 0.006 m. Low error in the movement suggests consistent trajectory is important to reduce extraneous movement and improve efficiency. While the kettlebell snatch and swing both require large anterior-posterior motion, the snatch requires the kettlebell to be held stationary overhead. Therefore, a different coaching application is required to that of a barbell snatch

    Entanglement dynamics in a non-Markovian environment: an exactly solvable model

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    We study the non-Markovian effects on the dynamics of entanglement in an exactly-solvable model that involves two independent oscillators each coupled to its own stochastic noise source. First, we develop Lie algebraic and functional integral methods to find an exact solution to the single-oscillator problem which includes an analytic expression for the density matrix and the complete statistics, i.e., the probability distribution functions for observables. For long bath time-correlations, we see non-monotonic evolution of the uncertainties in observables. Further, we extend this exact solution to the two-particle problem and find the dynamics of entanglement in a subspace. We find the phenomena of `sudden death' and `rebirth' of entanglement. Interestingly, all memory effects enter via the functional form of the energy and hence the time of death and rebirth is controlled by the amount of noisy energy added into each oscillator. If this energy increases above (decreases below) a threshold, we obtain sudden death (rebirth) of entanglement.Comment: 11 pages, 4 figures; revision for PR

    Prognostic Value of Estimating Functional Capacity with The Use of The Duke Activity Status Index in Stable Patients with Chronic Heart Failure

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    BACKGROUND: Over the years, several methods have been developed to reliably quantify functional capacity in patients with heart failure. Few studies have investigated the prognostic value of these assessment tools beyond cardiorenal prognostic biomarkers in stable patients with chronic heart failure. METHODS AND RESULTS: We administered the Duke Activity Status Index (DASI) questionnaire, a self-assessment tool comprising 12 questions for estimating functional capacity, to 1,700 stable nonacute coronary syndrome patients with history of heart failure who underwent elective diagnostic coronary angiography with 5-year follow-up of all-cause mortality. In a subset of patients (n = 800), B-type natriuretic peptide (BNP) was measured. In our study cohort, the median DASI score was 26.2 (interquartile range [IQR] 15.5-42.7). Low DASI score provided independent prediction of a 3.3-fold increase in 5-year mortality risk (quartile 1 vs quartile 4: hazard ratio [HR] 3.33, 95% confidence interval [CI] 2.57-4.36; P \u3c .0001). After adjusting for traditional risk factors, BNP, and estimated glomerular filtration rate, low DASI score still conferred a 2.6-fold increase in mortality risk (HR 2.57, 95% CI 1.64-4.15; P \u3c .0001). CONCLUSIONS: A simple self-assessment tool of functional capacity provides independent and incremental prognostic value for mortality prediction in stable patients with chronic heart failure beyond cardiorenal biomarkers

    Peroxisome Proliferator-Activated Receptor-α Activation Decreases Mean Arterial Pressure, Plasma Interleukin-6, and COX-2 While Increasing Renal CYP4A Expression in an Acute Model of DOCA-Salt Hypertension

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    Peroxisome proliferator-activated receptor-alpha (PPAR-α) activation by fenofibrate reduces blood pressure and sodium retention during DOCA-salt hypertension. PPAR-α activation reduces the expression of inflammatory cytokines, such as interleukin-6 (IL-6). Fenofibrate also induces cytochrome P450 4A (CYP4A) and increases 20-hydroxyeicosatetraenoic acid (20-HETE) production. This study tested whether the administration of fenofibrate would reduce blood pressure by attenuating plasma IL-6 and renal expression of cyclooxygenase-2 (COX-2), while increasing expression of renal CYP4A during 7 days of DOCA-salt hypertension. We performed uni-nephrectomy on 12–14 week old male Swiss Webster mice and implanted biotelemetry devices in control, DOCA-salt (1.5 mg/g) treated mice with or without fenofibrate (500 mg/kg/day in corn oil, intragastrically). Fenofibrate significantly decreased mean arterial pressure and plasma IL-6. In kidney homogenates, fenofibrate increased CYP4A and decreased COX-2 expression. There were no differences in renal cytochrome P450, family 2, subfamily c, polypeptide 23 (CYP2C23) and soluble expoxide hydrolase (sEH) expression between the groups. Our results suggest that the blood pressure lowering effect of PPAR-α activation by fenofibrate involves the reduction of plasma IL-6 and COX-2, while increasing CYP4A expression during DOCA-salt hypertension. Our results may also suggest that PPAR-α activation protects the kidney against renal injury via decreased COX-2 expression

    Prognostic Comparison of Different Sensitivity Cardiac Troponin Assays in Stable Heart Failure

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    Background: Cardiac troponin (cTn) levels offer prognostic information for patients with heart failure. Highly sensitive assays detect levels of cTn much lower than the 99th percentile of standard cTn assays. We hypothesize that cardiac troponin levels measured by a high-sensitivity assay provide better prognostic value compared with cTn levels measured by a standard assay in patients with chronic heart failure. Methods: We measured high-sensitivity cTnT (hs-cTnT) and standard cardiac troponin I (cTnI) levels, as well as amino-terminal pro B-type natriuretic peptide (NT-proBNP) in 504 sequential stable patients with a history of heart failure who underwent elective coronary angiography, without acute coronary syndrome, and with 5-year follow-up of all-cause mortality. Results: The median hs-cTnT level was 21.2 (interquartile range 12.3-40.9) ng/L and 170 subjects died over 5 years. In a head-to-head overall comparison, hs-cTnT provided increased prognostic utility compared with cTnI (area under the curve [AUC] 66.1% and AUC 69.4%, respectively, P = .03; 9.0% integrated discrimination improvement, P \u3c .001; and 13.6% event-specific reclassification, P \u3c .001), and was independent of NT-proBNP and renal function. Even within the subset of patients where cTn levels by both assays were above the limit of quantification, higher hs-cTnT is associated with a 2-fold increase in 5-year mortality risk after adjusting for traditional risk factors (tertile 1 vs 3: hazard ratio [95% confidence interval] 2.0 [1.3-3.2]; P = .0002). Conclusion: Cardiac troponin can be detected by the high-sensitivity assay in more patients with chronic heart failure than the standard assay, and may yield independent and better prognostic accuracy for mortality prediction than standard assay

    Criterion for Dominance of Directional over Size Fluctuations in Destroying Order

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    For systems exhibiting a second-order phase transition with a spontaneously broken continuous O(N)-symmetry at low temperature, we give a criterion for judging at which temperature T_K long-range directional fluctuations of the order field destroy the order when approaching the critical temperature from below. The temperature T_K lies always significantly below the famous Ginzburg temperature T_G at which size fluctuations of finite range in the order field become important.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/re3.html#29

    A multi-institution study of the impacts of concurrent work and study among university students in Australia

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    A growing number of university students balance concurrent study and work. Previous studies highlight potential benefits including heightened career awareness alongside risks including decreased study time. This study asked to what extent paid work affects university students’ self-assessment of perceived employability. The study employed an online survey with 38,458 domestic students from Australian universities; students were not working full-time. The findings suggest that full-time students who hold part-time or casual work are significantly more confident in their perceived employability, and significantly more likely to understand the relevance of their studies to their future career. Practical and theoretical implications are discussed

    Social Exclusion Modifies Climate and Deforestation Impacts on a Vector-Borne Disease

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    American Cutaneous Leishmaniasis emergence has been associated with changes in the interaction between people and forests. The association between outbreaks and forest clearance, higher risk for populations living close to forests, and the absence of this disease from urban settings has led to the proposal that it will disappear with the destruction of primary forests. This view ignores the complex nature of deforestation as a product of socioeconomic inequities. Our study shows that such inequities, as measured by a marginalization index, may ultimately determine risk within the country, with socially excluded populations most affected by the disease. Contrary to the established view, living close to the forest edge can diminish the risk provided other factors are taken into account. Additionally, differences in vulnerability to climatic variability appear to interact with forest cover to influence risk across counties where the disease has its largest burden. Incidence exacerbation associated with El Niño Southern Oscillation is observed in counties with larger proportions of deforestation. Our study calls for control efforts targeted to socially excluded populations and for more localized ecological studies of transmission in vectors and reservoirs in order to understand the role of biodiversity changes in driving the emergence of this disease

    In Situ Surface Voltage Measurements of Dielectrics Under Electron Beam Irradiation

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    New instrumentation has been developed for non-contact, in vacuo measurements of the electron beam-induced surface voltage as a function of time and position for non-conductive spacecraft materials in a simulated space environment. Used in conjunction with the capabilities of an existing ultrahigh vacuum electron emission analysis chamber, the new instrumentation facilitates measurements of charge accumulation, bulk resistivity, effects of charge depletion and accumulation on yield measurements, electron induced electrostatic breakdown potentials, radiation induced conductivity effects, and the radial dispersion of surface voltage. The novel system uses two movable capacitive sensor electrodes that can be swept across the sample to measure surface charge distributions on samples, using a non-contact method that does not dissipate sample charge. Design details, calibration and characterization measurements of the system are presented, for a surface voltage range from30 kV, voltage resolution \u3c1 \u3eV, and spatial resolutio
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