1,261,654 research outputs found

    Transport properties of the heavy fermion superconductor PrOs4_{4}Sb12_{12}

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    We have measured the electrical resistivity, thermoelectric power, Hall coefficient, and magnetoresistance (MR) on single crystals of PrOs4_{4}Sb12_{12}, LaOs4_{4}Sb12_{12} and NdOs4_{4}Sb12_{12}. All the transport properties in PrOs4_{4}Sb12_{12} are similar to those in LaOs4_{4}Sb12_{12} and NdOs4_{4}Sb12_{12} at high temperatures, indicating the localized character of 4ff-electrons. The transverse MR both in LaOs4_{4}Sb12_{12} and PrOs4_{4}Sb12_{12} tends to saturate for wide field directions, indicating these compounds to be uncompensated metals with no open orbit. We have determined the phase diagram of the field induced ordered phase by the MR measurement for all the principle field directions, which indicates an unambiguous evidence for the Γ1\Gamma_{\rm 1} singlet crystalline electric field ground state.Comment: 7 pages, 10 figures, to appear in Physical Review

    The ergogenic effect of beta-alanine combined with sodium bicarbonate on high-intensity swimming performance

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    We investigated the effect of beta-alanine (BA) alone (study A) and in combination with sodium bicarbonate (SB) (study B) on 100- and 200-m swimming performance. In study A, 16 swimmers were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 4 weeks) or placebo (PL; dextrose). At baseline and after 5 weeks of supplementation, 100- and 200-m races were completed. In study B, 14 were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 3 weeks) or PL. Time trials were performed once before and twice after supplementation (with PL and SB), in a crossover fashion, providing 4 conditions: PL-PL, PL-SB, BA-PL, and BA-SB. In study A, BA supplementation improved 100- and 200-m time-trial performance by 2.1% (p = 0.029) and 2.0% (p = 0.0008), respectively. In study B, 200-m time-trial performance improved in all conditions, compared with presupplementation, except the PL-PL condition (PL-SB, +2.3%; BA-PL, +1.5%; BA-SB, +2.13% (p < 0.05)). BA-SB was not different from BA-PL (p = 0.21), but the probability of a positive effect was 78.5%. In the 100-m time-trial, only a within-group effect for SB was observed in the PL-SB (p = 0.022) and BA-SB (p = 0.051) conditions. However, 6 of 7 athletes swam faster after BA supplementation. The probability of BA having a positive effect was 65.2%; when SB was added to BA, the probability was 71.8%. BA and SB supplementation improved 100- and 200-m swimming performance. The coingestion of BA and SB induced a further nonsignificant improvement in performance

    Is urinary incontinence associated with sedentary behaviour in older women? Analysis of data from the National Health and Nutrition Examination Survey

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    BACKGROUND: Urinary incontinence (UI) is a common geriatric syndrome associated with physical and cognitive impairments. The association between type of UI and sedentary behaviour (SB) has not been explored. AIM: To determine association between moderate-severe UI, or any stress UI (SUI) or any urgency UI (UUI) and SB in community-dwelling older women. METHODS: Women aged 60 and over from the 2005-2006 cycle of the National Health and Nutrition Examination Survey (NHANES) with objectively measured (accelerometer) and self-reported SB and UI data were selected. Multivariate models exploring association between moderate-severe UI and SB, or SUI and SB, or UUI and SB were analysed using logistic regression adjusted for factors associated with UI. RESULTS: In the overall sample of 459 older women, 23.5% reported moderate-severe UI, 50.5% reported any SUI and 41.4% reported any UUI. In bivariate analysis objectively measured proportion of time in SB was associated with moderate-severe UI and UUI (p = 0.014 and p = 0.047) but not SUI. Average duration of SB bouts in those with moderate-severe UI or any SUI was no longer than older women reporting no continence issues, but it was significantly (19%) longer in older women with any UUI (mean difference 3.2 minutes; p = 0.001). Self-reported SB variables were not associated with any type of UI. Multivariate analysis showed an association between UUI and a longer average duration of SB bouts (OR = 1.05, 95% CI = 1.01-1.09, p = 0.006) but no association with moderate-severe UI or SUI. CONCLUSION: UUI was significantly associated with increased average duration of SB bouts in community-dwelling older women. The importance of objective measurement of SB is highlighted and suggests that decreasing time in prolonged sitting may be a target intervention to reduce UUI. Future studies are required to further explore the association between SB and incontinence

    Prevalence of Physical Activity and Sedentary Behavior among Chinese Children and Adolescents: Variations, Gaps, and Recommendations

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    Physical-activity (PA) and sedentary-behavior (SB) assessment is of particular importance in the promotion of health in young people. However, there is no comprehensive overview of PA and SB from national surveys among Chinese children and adolescents. Following a literature search for Chinese national health surveys, 11 papers from six national surveys were found. Of the included studies, the majority applied self-reported questionnaires to estimate the prevalence of PA and SB. Owing to different definitions of the prevalence of PA and SB and various measures, a large variation in prevalence of PA and SB was observed. Such variations were attributable to methodological and practical issues. This study highlights the current gaps in estimating the national prevalence of PA and SB among Chinese children and adolescents, which should be addressed. To improve the quality of PA and SB surveillance, standardized measurement protocols to estimate the prevalence of PA and SB more accurately among Chinese children and adolescents are urgently required

    Joint effect of physical activity and sedentary behaviour on cardiovascular risk factors in Chilean adults

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    Background: To investigate the associations between combined categories of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with markers of adiposity and cardiovascular risk in adults. Methods: Overall, 5040 participants (mean age 46.4 years and 59.3% women) from the cross-sectional Chilean National Health Survey 2009–2010 were included in this study. MVPA and SB were measured using the Global Physical Activity questionnaire. Four categories were computed using MVPA- and SB-specific cut-offs (‘High-SB &#38; Active’, ‘Low-SB &#38; Active’, ‘High-SB &#38; Inactive’ and ‘Low-SB &#38; Inactive’). Results: Compared to the reference group (‘High-SB &#38; Inactive’), those in ‘High-SB &#38; Active’ and ‘Low-SB &#38; Active’ were less likely to have an obese BMI (OR: 0.67 [0.54; 0.85], P = 0.0001 and 0.74 [0.59; 0.92] P = 0.0007, respectively) and less likely to have metabolic syndrome (OR: 0.63 [0.49; 0.82], P &lt; 0.0001 and 0.72 [0.57; 0.91], P = 0.007), central obesity (OR: 0.79 [0.65; 0.96], P = 0.016 and 0.71 [0.59; 0.84], P &lt; 0.0001), diabetes (OR: 0.45 [0.35; 0.59], P &lt; 0.0001 and 0.44 [0.34; 0.56], P &lt; 0.0001) and hypertension (OR: 0.52 [0.43; 0.63], P &lt; 0.0001 and 0.60 [0.50; 0.72], P &lt; 0.0001), respectively. Conclusions: Being physically active and spending less time in SBs was associated with lower adiposity and improvements in cardiovascular risk factors

    Distortion of boundary sets under inner functions and applications

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    10 pages, no figures.-- MSC2000 codes: 30C85, 30D50.MR#: MR1183352 (93k:30014)Zbl#: Zbl 0765.30011An inner function is a bounded holomorphic function from the unit disc Δ\Delta of the complex plane such that the radial boundary values have modulus 1 a.e. . If EE is a Borel subset of ∂Δ\partial\Delta we also define f(E)=\{e\sp{i\theta}/\lim\sb{r\to 1} f(re\sp{i\theta}) exists and belongs to E}E\}. Let M\sb \alpha, \text{cap}\sb \alpha and dim denote respectively the α\alpha-dimensional content, α\alpha- dimensional capacity and the Hausdorff dimension. In relation to the available results the authors in this paper prove that if ff is inner, f(0)=0f(0)=0, and EE is a Borel subset of ∂Δ\partial\Delta then M\sb \alpha(f\sp{-1}(E)) \geq C\sb \alpha M\sb \alpha(E) and for 0≤α<10\leq\alpha<1, \text{cap}\sb \alpha(f\sp{-1}(E)) \geq C\sb \alpha \text{cap}\sb \alpha(E). An immediate consequence of course is \dim(f\sp{-1}(E))\geq \dim E. They also give examples to show that the inequalities cannot be reversed [source: Zentralblatt MATH].The first author was supported in part by a grant from CICYT, Ministerio de Educación y Ciencia, Spain.Publicad

    Theory of Adsorption and Surfactant Effect of Sb on Ag (111)

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    We present first-principles studies of the adsorption of Sb and Ag on clean and Sb-covered Ag (111). For Sb, the {\it substitutional} adsorption site is found to be greatly favored with respect to on-surface fcc sites and to subsurface sites, so that a segregating surface alloy layer is formed. Adsorbed silver adatoms are more strongly bound on clean Ag(111) than on Sb-covered Ag. We propose that the experimentally reported surfactant effect of Sb is due to Sb adsorbates reducing the Ag adatom mobility. This gives rise to a high density of Ag islands which coalesce into regular layers.Comment: RevTeX 3.0, 11 pages, 0 figures] 13 July 199
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