30 research outputs found
The travel demands of an elite rugby sevens team: Effects on objective and subjective sleep parameters
Purpose: To explore the effects of travel related to international rugby sevens competition on sleep patterns. Methods: Seventeen international male rugby sevens players participated in this study. Sleep assessments were performed daily during two separate Sevens World Series competition legs (Oceania and America). The duration of each competition leg was subdivided into key periods (pre-tour, pre-competition, tournament 1 and 2, relocation and post-tour) lasting 2 to 7 nights. Linear mixed models in combination with magnitude-based decision were used to assess 1) the difference between pre-season and key periods and 2) the effect of travel direction (eastward or westward). Results: Shorter total sleep time (hh:mm) was observed during tournament 2 (mean ± SD, 06:16 ± 01:08), relocation (06:09 ± 01:09) and pre-tour week (06:34 ± 01:24) compared with pre-season (06:52 ± 01:00). Worse sleep quality (AU) was observed during tournament 1 (6.1 ± 65 2.0) and 2 (5.7 ± 1.2) as well as during the relocation week (6.3 ± 1.5) than during pre-season (6.5 ± 1.8). When traveling eastward compared with westward, earlier fall asleep time was observed during tournament 1 (ES -0.57, 90%CI [-1.12 to -0.01]), relocation week (-0.70 [-1.11 to -0.28]), and post-tour (-0.57 [-0.95 to -0.18]). However, possibly trivial and unclear differences were observed during pre-competition week (0.15 [-0.15 to 0.45]) and tournament 2 (0.81 [-0.29 to 1.91]). Conclusion: Sleep patterns of elite rugby sevens players are robust to the effects of long-haul travel and jet lag. However, staff should consider promoting sleep during the tournament and 73 relocation week
Microscopic Model of Charge Carrier Transfer in Complex Media
We present a microscopic model of a charge carrier transfer under an action
of a constant electric field in a complex medium. Generalizing previous
theoretical approaches, we model the dynamical environment hindering the
carrier motion by dynamic percolation, i.e., as a medium comprising particles
which move randomly on a simple cubic lattice, constrained by hard-core
exclusion, and may spontaneously annihilate and re-appear at some prescribed
rates. We determine analytically the density profiles of the "environment"
particles, as seen from the stationary moving charge carrier, and calculate its
terminal velocity as the function of the applied field and other system
parameters. We realize that for sufficiently small external fields the force
exerted on the carrier by the "environment" particles shows a viscous-like
behavior and define an analog of the Stokes formula for such dynamic
percolative environments. The corresponding friction coefficient is also
derived.Comment: appearing in Chem. Phys. Special Issue on Molecular Charge Transfer
in Condensed Media - from Physics and Chemistry to Biology and
Nano-Engineering, edited by A.Kornyshev (Imperial College London), M.Newton
(Brookhaven Natl Lab) and J.Ulstrup (Technical University of Denmark
Generalized model for dynamic percolation
We study the dynamics of a carrier, which performs a biased motion under the
influence of an external field E, in an environment which is modeled by dynamic
percolation and created by hard-core particles. The particles move randomly on
a simple cubic lattice, constrained by hard-core exclusion, and they
spontaneously annihilate and re-appear at some prescribed rates. Using
decoupling of the third-order correlation functions into the product of the
pairwise carrier-particle correlations we determine the density profiles of the
"environment" particles, as seen from the stationary moving carrier, and
calculate its terminal velocity, V_c, as the function of the applied field and
other system parameters. We find that for sufficiently small driving forces the
force exerted on the carrier by the "environment" particles shows a
viscous-like behavior. An analog Stokes formula for such dynamic percolative
environments and the corresponding friction coefficient are derived. We show
that the density profile of the environment particles is strongly
inhomogeneous: In front of the stationary moving carrier the density is higher
than the average density, , and approaches the average value as an
exponential function of the distance from the carrier. Past the carrier the
local density is lower than and the relaxation towards may
proceed differently depending on whether the particles number is or is not
explicitly conserved.Comment: Latex, 32 pages, 4 ps-figures, submitted to PR
La conservazione preventiva del patrimonio librario come possibile alternativa al restauro tradizionale
The present paper focuses on the close relation between library collections and their preservation environment, aiming, in particular, at highlighting the importance of promoting and sustaining the monitoring. The paper proposes some simple and ready-to-use technologies – smart monitoring – to prevent future damages