1,891 research outputs found
Match injuries in professional soccer: inter-seasonal variation and effects of competition type, match congestion and positional role
In this prospective observational study, injuries sustained in official match-play in players belonging to a professional soccer club were investigated. Incidence and patterns of injury were compared across four-seasons (2005-2006: S1, 2006-2007: S2, 2007-2008: S3 and 2008-2009: S4) and 3 match formats (domestic League/Cup games and European club competition). In addition, the effects of both fixture congestion and the positional role of players were investigated. Injury incidence (per 1 000 match-hours) did not vary between seasons (range 31.2-59.2 observed in S2 and S4, respectively, p=0.12) or fixture formats (range 32.6-40.8 observed in European and League matches, respectively, p=0.49). In contrast, rates varied in players (n=7) who participated in all four seasons as more injuries were sustained in S1 compared to S2 and S3, respectively (88.4 vs. 49.0 vs. 49.2, both p or = 4 days). Finally, the incidence of injury and muscle strains (both p<0.001) varied across positional roles with the highest rates observed in centre-forwards. These findings provide further knowledge on the risk of injury in contemporary professional soccer match-play and may aid in the care and management of playing resources
The topological structure of scaling limits of large planar maps
We discuss scaling limits of large bipartite planar maps. If p is a fixed
integer strictly greater than 1, we consider a random planar map M(n) which is
uniformly distributed over the set of all 2p-angulations with n faces. Then, at
least along a suitable subsequence, the metric space M(n) equipped with the
graph distance rescaled by the factor n to the power -1/4 converges in
distribution as n tends to infinity towards a limiting random compact metric
space, in the sense of the Gromov-Hausdorff distance. We prove that the
topology of the limiting space is uniquely determined independently of p, and
that this space can be obtained as the quotient of the Continuum Random Tree
for an equivalence relation which is defined from Brownian labels attached to
the vertices. We also verify that the Hausdorff dimension of the limit is
almost surely equal to 4.Comment: 45 pages Second version with minor modification
Therapeutic Strategies Targeting DUX4 in FSHD
Facioscapulohumeral muscular dystrophy (FSHD) is a common muscle dystrophy typically affecting patients within their second decade. Patients initially exhibit asymmetric facial and humeral muscle damage, followed by lower body muscle involvement. FSHD is associated with a derepression of DUX4 gene encoded by the D4Z4 macrosatellite located on the subtelomeric part of chromosome 4. DUX4 is a highly regulated transcription factor and its expression in skeletal muscle contributes to multiple cellular toxicities and pathologies ultimately leading to muscle weakness and atrophy. Since the discovery of the FSHD candidate gene DUX4, many cell and animal models have been designed for therapeutic approaches and clinical trials. Today there is no treatment available for FSHD patients and therapeutic strategies targeting DUX4 toxicity in skeletal muscle are being actively investigated. In this review, we will discuss different research areas that are currently being considered to alter DUX4 expression and toxicity in muscle tissue and the cell and animal models designed to date
Electron-nuclei spin dynamics in II-VI semiconductor quantum dots
We report on the dynamics of optically induced nuclear spin polarization in
individual CdTe/ZnTe quantum dots loaded with one electron by modulation
doping. The fine structure of the hot trion (charged exciton with an
electron in the -shell) is identified in photoluminescence excitation
spectra. A negative polarisation rate of the photoluminescence, optical pumping
of the resident electron and the built-up of dynamic nuclear spin polarisation
(DNSP) are observed in time-resolved optical pumping experiments when the
quantum dot is excited at higher energy than the hot trion triplet state. The
time and magnetic field dependence of the polarisation rate of the
emission allows to probe the dynamics of formation of the DNSP in the optical
pumping regime. We demonstrate using time-resolved measurements that the
creation of a DNSP at B=0T efficiently prevents longitudinal spin relaxation of
the electron caused by fluctuations of the nuclear spin bath. The DNSP is built
in the microsecond range at high excitation intensity. A relaxation time of the
DNSP in about 10 microseconds is observed at and significantly increases
under a magnetic field of a few milli-Tesla. We discuss mechanisms responsible
for the fast initialisation and relaxation of the diluted nuclear spins in this
system
The Coarse Geometry of Merger Trees in \Lambda CDM
We introduce the contour process to describe the geometrical properties of
merger trees. The contour process produces a one-dimensional object, the
contour walk, which is a translation of the merger tree. We portray the contour
walk through its length and action. The length is proportional to to the number
of progenitors in the tree, and the action can be interpreted as a proxy of the
mean length of a branch in a merger tree.
We obtain the contour walk for merger trees extracted from the public
database of the Millennium Run and also for merger trees constructed with a
public Monte-Carlo code which implements a Markovian algorithm. The trees
correspond to halos of final masses between 10^{11} h^{-1} M_sol and 10^{14}
h^{-1} M_sol. We study how the length and action of the walks evolve with the
mass of the final halo. In all the cases, except for the action measured from
Markovian trees, we find a transitional scale around 3 \times 10^{12} h^{-1}
M_sol. As a general trend the length and action measured from the Markovian
trees show a large scatter in comparison with the case of the Millennium Run
trees.Comment: 7 pages, 5 figures, submitted to MNRA
A four-season prospective study of muscle strain reoccurrences in a professional football club
The aim of this investigation was to characterise muscle strain reinjuries and examine their impact on playing resources in a professional football club. Muscle strains and reoccurrences were prospectively diagnosed over four seasons in first-team players (n = 46). Altogether, 188 muscle strains were diagnosed with 44 (23.4%) of these classed as reinjuries, leading to an incidence of 1.32 strain reoccurrences per 1,000 hours exposure (95% Confidence Interval [CI], 0.93–1.71). The incidence of recurrent strains was higher in match-play compared with training (4.51, 95% CI, 2.30–6.72 vs 0.94, 95% CI, 0.59–1.29). Altogether, 50.0% of players sustained at least 1 reoccurrence of a muscle strain, leading to approximately 3 days lost and 0.4 matches missed per player per season. The incidence of recurrent strains was highest in centre-forwards (2.15, 95% CI, 1.06–3.24), peaked in May (3.78, 95% CI, 0.47–7.09), and mostly affected the hamstrings (38.6% of all reoccurrences). Mean layoff for nonreoccurrences and recurrences was similar: ∼7.5 days. These results provide greater insight into the extent of the problem of recurrent muscle strains in professional football
High throughput methodology for synthesis, screening, and optimization of solid state Lithium ion electrolytes
A study of the lithium ion conductor Li3xLa2/3–xTiO3 solid solution and the surrounding composition space was carried out using a high throughput physical vapor deposition system. An optimum total ionic conductivity value of 5.45 × 10–4 S cm–1 was obtained for the composition Li0.17La0.29Ti0.54 (Li3xLa2/3–xTiO3x = 0.11). This optimum value was calculated using an artificial neural network model based on the empirical data. Due to the large scale of the data set produced and the complexity of synthesis, informatics tools were required to analyze the data. Partition analysis was carried out to determine the synthetic parameters of importance and their threshold values. Multivariate curve resolution and principal component analysis were applied to the diffraction data set. This analysis enabled the construction of phase distribution diagrams, illustrating both the phases obtained and the compositional zones in which they occur. The synthetic technique presented has significant advantages over other thin film and bulk methodologies, in terms of both the compositional range covered and the nature of the materials produce
Fractional Generalization of Kac Integral
Generalization of the Kac integral and Kac method for paths measure based on
the Levy distribution has been used to derive fractional diffusion equation.
Application to nonlinear fractional Ginzburg-Landau equation is discussed.Comment: 16 pages, LaTe
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