156 research outputs found

    The effectiveness of the Wim Hof method on cardiac autonomic function, blood pressure, arterial compliance, and different psychological parameters.

    Get PDF
    The Wim Hof method (WHM) is a multi-disciplinary approach to physical and mental well-being combining cold exposure, breathing exercises, and meditation. This study evaluated the effects of a 15 days WHM intervention on cardiovascular parameters at rest and during a cold pressor test (CPT), as well as on various psychological parameters. Forty two participants were randomized into an intervention (IG) and a control group. Throughout the 15 days intervention, the IG performed the WHM daily. Before and after the intervention, systolic (SBP) and diastolic blood pressure (DBP), pulse wave velocity (PWV), heart rate (HR), root mean sum of squared distance (RMSSD), and standard deviation of RR-intervals (SDNN) were assessed at rest and during a CPT. Furthermore, perceived stress (PSS), positive affect (PANAS+), negative affect (PANAS-), and subjective vitality (trait (SVSt) and state (SVSs)) was determined. No significant time × group interactions could be detected in HR (p = 0.709); RMSSD (p = 0.820), SDNN (p = 0.186), SBP (p = 0.839), DBP (p = 0.318), PWV (p = 0.983), PANAS+ (p = 0.427), PANAS- (p = 0.614), SVSt (p = 0.760), SVSs (p = 0.366), and PSS (p = 0.364). No significant time × group effects could be detected during the CPT (ΔHR: p = 0.596; ΔSBP: p = 0.366; ΔDBP: p = 0.999; ΔPWV: p = 0.635; perceived pain: p = 0.231). Performing the WHM daily did not exert positive effects on cardiovascular and psychological parameters

    Wave nucleation rate in excitable systems in the low noise limit

    Full text link
    Motivated by recent experiments on intracellular calcium dynamics, we study the general issue of fluctuation-induced nucleation of waves in excitable media. We utilize a stochastic Fitzhugh-Nagumo model for this study, a spatially-extended non-potential pair of equations driven by thermal (i.e. white) noise. The nucleation rate is determined by finding the most probable escape path via minimization of an action related to the deviation of the fields from their deterministic trajectories. Our results pave the way both for studies of more realistic models of calcium dynamics as well as of nucleation phenomena in other non-equilibrium pattern-forming processes

    Fundamental scaling laws of on-off intermittency in a stochastically driven dissipative pattern forming system

    Full text link
    Noise driven electroconvection in sandwich cells of nematic liquid crystals exhibits on-off intermittent behaviour at the onset of the instability. We study laser scattering of convection rolls to characterize the wavelengths and the trajectories of the stochastic amplitudes of the intermittent structures. The pattern wavelengths and the statistics of these trajectories are in quantitative agreement with simulations of the linearized electrohydrodynamic equations. The fundamental τ3/2\tau^{-3/2} distribution law for the durations τ\tau of laminar phases as well as the power law of the amplitude distribution of intermittent bursts are confirmed in the experiments. Power spectral densities of the experimental and numerically simulated trajectories are discussed.Comment: 20 pages and 17 figure

    Vida productiva, supervivencia, descartes y muertes de vacas en diferentes cruzamientos de razas lecheras en un sistema a pastoreo

    Get PDF
    The objective of this work was to evaluate the duration of productive life, survival to subsequent calving, discards and deaths in different crosses of dairy breeds in a grazing commercial dairy farm. Retrospective data from a commercial farm in the province of Santa Fe, Argentina, were analyzed. The period evaluated ranged from August 1, 2017, to January 12, 2021. The database consisted of 1,342 lactations of pure Holstein breed (HO; n: 799 cows), 344 lactations of HO x Jersey cross (JY; n: 164 cows), 190 lactations of the JY x Montbeliarde cross (MO; n: 96 cows) and 316 lactations of the MO x HO cross (XB; n: 134 cows). No significant differences were found between the survival curves of the productive life variable between the pure HO breed and the evaluated crosses (p=0.1281). When the survival to subsequent calving was analyzed, it was found that all the crosses were superior both in the second and in the third calving, with respect to the pure HO cows. No significant differences were found in culling and mortality variables between HO cows and the different crosses. It is concluded that the length of the productive life was similar between the pure breed HO and the studied crosses JY, MO and XB. Finally, culling and deaths were similar between the purebred (HO) and the JY, MO and XB crosses, although MO cows showed the lowest mortality rates.El objetivo de este trabajo fue evaluar la duración de la vida productiva, la supervivencia a los partos posteriores, los descartes y muertes en diferentes cruzamientos de razas lecheras en un tambo comercial a pastoreo. Se analizaron datos retrospectivos de un tambo comercial de la provincia de Santa Fe, Argentina. El período de tiempo evaluado fue desde el 1 de agosto del 2017 al 12 de enero del 2021. La base de datos constaba de 1342 lactancias de raza Holstein puras (HO; n: 799 vacas), 344 lactancias de cruza HO x Jersey (JY; n: 164 vacas), 190 lactancias de la cruza JY x Montbeliarde (MO; n: 96 vacas) y 316 lactancias de la cruza MO x HO (XB; n: 134 vacas). No se hallaron diferencias significativas entre las curvas de supervivencia de la variable vida productiva entre la raza HO pura y los cruzamientos evaluados (p=0,1281). Cuando se analizó la supervivencia a los partos posteriores, se encontró que todos los cruzamientos fueron superiores tanto en el segundo como en el tercer parto, con respecto a las vacas HO puras. No se encontraron diferencias significativas en las variables descarte y muerte entre las vacas HO y las diferentes cruzas. Se concluye que la longitud de la vida productiva fue similar entre la raza pura HO y los cruzamientos estudiados JY, MO y XB. Finalmente, los descartes y las muertes fueron similares entre la raza pura (HO) y los cruzamientos JY, MO y XB, aunque las muertes en las vacas MO mostraron los menores valores

    Crossover Scaling in Dendritic Evolution at Low Undercooling

    Full text link
    We examine scaling in two-dimensional simulations of dendritic growth at low undercooling, as well as in three-dimensional pivalic acid dendrites grown on NASA's USMP-4 Isothermal Dendritic Growth Experiment. We report new results on self-similar evolution in both the experiments and simulations. We find that the time dependent scaling of our low undercooling simulations displays a cross-over scaling from a regime different than that characterizing Laplacian growth to steady-state growth

    Regular dendritic patterns induced by non-local time-periodic forcing

    Full text link
    The dynamic response of dendritic solidification to spatially homogeneous time-periodic forcing has been studied. Phase-field calculations performed in two dimensions (2D) and experiments on thin (quasi 2D) liquid crystal layers show that the frequency of dendritic side-branching can be tuned by oscillatory pressure or heating. The sensitivity of this phenomenon to the relevant parameters, the frequency and amplitude of the modulation, the initial undercooling and the anisotropies of the interfacial free energy and molecule attachment kinetics, has been explored. It has been demonstrated that besides the side-branching mode synchronous with external forcing as emerging from the linear Wentzel-Kramers-Brillouin analysis, modes that oscillate with higher harmonic frequencies are also present with perceptible amplitudes.Comment: 15 pages, 23 figures, Submitted to Phys. Rev.

    Modulation of Localized States in Electroconvection

    Full text link
    We report on the effects of temporal modulation of the driving force on a particular class of localized states, known as worms, that have been observed in electroconvection in nematic liquid crystals. The worms consist of the superposition of traveling waves and have been observed to have unique, small widths, but to vary in length. The transition from the pure conduction state to worms occurs via a backward bifurcation. A possible explanation of the formation of the worms has been given in terms of coupled amplitude equations. Because the worms consist of the superposition of traveling waves, temporal modulation of the control parameter is a useful probe of the dynamics of the system. We observe that temporal modulation increases the average length of the worms and stabilizes worms below the transition point in the absence of modulation.Comment: 4 pages, 4 figure

    Bryophytes of Europe Traits (BET) dataset: a fundamental tool for ecological studies

    Get PDF
    Bryophytes are a diverse group of organisms with unique properties, yet they are severely underrepresented in plant trait databases. Building on the recently published European Red List of bryophytes and previous trait compilations, we present the Bryophytes of Europe Traits (BET) data set, including biological traits such as those related to life history, growth habit, sexual and vegetative reproduction; ecological traits such as indicator values, substrate and habitat; and bioclimatic variables based on the species' European range. The data set includes values for 65 traits and 25 bio-climatic variables, containing more than 135,000 trait values with a completeness of 82.7% on average. The data set will enable future studies in bryophyte biology, ecology and conservation, and may help to answer fundamental questions in bryology.info:eu-repo/semantics/publishedVersio

    Co-ordination of local policies for urban development and public transportation in four Swiss cities

    Get PDF
    The present article aims at assessing the possibility for urban areas to coordinate local policies of urban development and public transportation and at explaining the differences in this achievement between urban regions. In order to do so, the study draws support from two empirical sources: a historical analysis of the "mass-production" generated by the public service sectors in the field of transport and urban development in the cities of Basel, Bern, Geneva, and Lausanne since 1950, and a series of six case studies in these four cities. The study identifies factors located both at context level regarding morphological and geographical conditions as well as institutional settings and case-specific idiosyncrasies regarding organizational structure, past policy decisions, as well as vocational cultures that determine the possibility for urban areas to meet the need for policy coordination

    Promoting More Physical Activity and Less Sedentary Behaviour During the COVID-19 Situation – SportStudisMoveYou (SSMY): A Randomized Controlled Trial

    Get PDF
    Objective: To determine the effect of an innovative, online-based intervention, addressing the possible decline of physical activity (PA) and increase of sedentary behavior (SB) during COVID-19 stay at home restrictions in Switzerland. Methods: This study investigated the effect of a two-week, social cognitive theory based, online-video moderate to vigorous (MV)PA or SB intervention on MVPA and SB behaviour and intention via a 3 group by 2 time point parallel randomized controlled trial during the COVID-19 pandemic. Adults (≥18 yo) were recruited over the internet between April 10th and April 19th 2020 (n = 129; 75.2% female; mean age = 29.0 [SD 11.8] years). Both intervention groups received five videos targeting either SB for the SB group or MVPA for the MVPA group and were compared to an attention control group (fruit and vegetable consumption). It was hypothesized that MVPA time and intention would increase for the MVPA group and the SB group would outperform control on SB behaviour and intention indicators. Results: No significant interactions were found for the MVPA group (n = 41) versus control (n = 40). Only one significant interaction was measured for the SB group (n = 48; intention of active breaks F = (2,114) = 5.84, p = 0.004, ηp2 = 0.09). Although mostly non-significant and small effects, the MVPA group showed results pointing in the hypothesized direction on all PA indicators and the SB on all SB indicators, respectively. Conclusion: Considering this study’s limitations (e.g. small intervention dose), video-based online PA and SB interventions seem promising and feasible. This approach is appropriate for COVID-19 and other stay at home situations
    corecore