1,998 research outputs found
Editorial: Coaches' role in youth sports performance: early specialization versus long-term development
Youth sports are planned sports programs for children and adolescents with designated
coaches, organized practices, and scheduled competitions. Such programs can be organized and
implemented at schools (by physical education teachers instead of coaches), as well as in other
sports organizations (i.e., federations, associations, local clubs). Primary aim should be to focus
on providing young athletes with fundamental motor skills in tandem to their maturation stage.
Indeed, these programs are aimed at mass participation rather than on developing elite athletes.
The participation in such programs during childhood and adolescence showed to have major
benefits in children’s and adolescent’s physical, psychological, and social development. On the other
hand, youth sports programs can also serve as a link to talent identification and development
programs aiming to identify young athletes with potential for success in adult/elite sport. As they
aremass orientated,many youth athletes can be observed which will increase the likelihood of talent
identification. Afterwards, these athletes can be guided to high-performance programs aiming to
achieve eventually an elite level.info:eu-repo/semantics/publishedVersio
Maximally-localized Wannier functions for entangled energy bands
We present a method for obtaining well-localized Wannier-like functions (WFs)
for energy bands that are attached to or mixed with other bands. The present
scheme removes the limitation of the usual maximally-localized WFs method (N.
Marzari and D. Vanderbilt, Phys. Rev. B 56, 12847 (1997)) that the bands of
interest should form an isolated group, separated by gaps from higher and lower
bands everywhere in the Brillouin zone. An energy window encompassing N bands
of interest is specified by the user, and the algorithm then proceeds to
disentangle these from the remaining bands inside the window by filtering out
an optimally connected N-dimensional subspace. This is achieved by minimizing a
functional that measures the subspace dispersion across the Brillouin zone. The
maximally-localized WFs for the optimal subspace are then obtained via the
algorithm of Marzari and Vanderbilt. The method, which functions as a
postprocessing step using the output of conventional electronic-structure
codes, is applied to the s and d bands of copper, and to the valence and
low-lying conduction bands of silicon. For the low-lying nearly-free-electron
bands of copper we find WFs which are centered at the tetrahedral interstitial
sites, suggesting an alternative tight-binding parametrization.Comment: 13 pages, with 9 postscript figures embedded. Uses REVTEX and epsf
macro
Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems
A transfer matrix scaling technique is developed for randomly diluted
systems, and applied to the site-diluted Ising model on a square lattice in two
dimensions. For each allowed disorder configuration between two adjacent
columns, the contribution of the respective transfer matrix to the decay of
correlations is considered only as far as the ratio of its two largest
eigenvalues, allowing an economical calculation of a configuration-averaged
correlation length. Standard phenomenological-renormalisation procedures are
then used to analyse aspects of the phase boundary which are difficult to
assess accurately by alternative methods. For magnetic site concentration
close to , the extent of exponential behaviour of the curve
is clearly seen for over two decades of variation of . Close to the
pure-system limit, the exactly-known reduced slope is reproduced to a very good
approximation, though with non-monotonic convergence. The averaged correlation
lengths are inserted into the exponent-amplitude relationship predicted by
conformal invariance to hold at criticality. The resulting exponent
remains near the pure value (1/4) for all intermediate concentrations until it
crosses over to the percolation value at the threshold.Comment: RevTeX 3, 11 pages +5 figures, uuencoded, to appear in Phys. Rev. B
(1994), PUC/RJ preprin
1H low- and high-field NMR study of the effects of plasma treatment on the oil and water fractions in crude heavy oil
AbstractThe chemical and physical properties of a Brazilian heavy oil submitted to plasma treatment were investigated by 1H low- and high-field nuclear magnetic resonance (NMR) combined to the characterization of rheological properties, thermogravimetry and measurement of basic sediments and water (BSW) content. The crude oil was treated in a dielectric barrier discharge plasma reactor, using natural gas, CO2 or H2 as working gas. The results indicated a large drop in the water content of the plasma-treated samples as compared to the crude oil, giving rise to a reduction in the viscosity. No significant chemical change was produced in the oil portion itself, as observed by 1H NMR. The water contents determined by 1H low-field NMR analyses agreed well with those obtained by BSW, indicating the low-field NMR methods as a useful tool for following the effects of plasma treatments on heavy oils, allowing the separation of the effects caused on the water and oil fractions
Cardiovascular autonomic modulation differences between moderate-intensity continuous and high-intensity interval aerobic training in women with PCOS: A randomized trial
Background: Moderate-intensity continuous training (MICT) is strongly recommended for polycystic ovarian syndrome (PCOS) treatment. However, recent studies have suggested that high-intensity interval training (HIIT) would promote great benefits for cardiac autonomic control. Therefore, we investigated whether the benefits of HIIT related to cardiovascular autonomic control were greater than those of MICT in women with PCOS.
Methods: Women with PCOS were randomly allocated through a blind draw into three groups: control, MICT, and HIIT. The control group did not undergo exercise, whereas those in the MICT and HIIT groups underwent 16 weeks of aerobic physical training. All groups were evaluated before and after the 16 weeks of intervention in the following aspects: quantification of serum lipids, testosterone, fasting insulin and blood glucose; physical fitness through cardiopulmonary testing; analysis of heart rate variability (HRV) by linear (time domain and frequency domain) and non-linear (symbolic analysis) methods, analysis of blood pressure variability (BPV) and spontaneous baroreflex sensitivity (BRS).
Results: The final analysis, each group comprised 25 individuals. All groups had similar baseline parameters. After 16 weeks, intragroup comparison showed that the MICT and HIIT groups had a reduction in baseline heart rate (P < 0.001; P < 0.001, respectively) and testosterone levels P < 0.037; P < 0.012, respectively) associated with an increase in VO2peak (MICT, P < 0.001; HIIT, P < 0.001). The MICT (P < 0.36) and HIIT (P < 0.17) groups also showed an increase in cardiac vagal modulation, however only observed in the non-linear analysis. The intergroup comparison showed no differences between the MICT and HIIT groups in any of the hormonal, metabolic and autonomic parameters evaluated, including testosterone, peak oxygen uptake (VO2peak), HRV, BPV and BRS.
Conclusion: HIIT and MICT showed similar results for the different parameters evaluated. This suggests that both training protocols can be recommended for the treatment of PCOS. Brazilian Clinical Trials Registry (RBR-78qtwy)
Produção imobiliária residencial, Florianópolis 1980-2010
A produção habitacional formal, por suas características e especificidades, ocupa um papel destacado na organização do espaço urbano e projeta sobre ele as relações capitalistas. Se o metabolismo socioeconômico mais geral se altera, também se altera o modo de produção do espaço urbano e da moradia.
Esta pesquisa tem por objetivo compreender as principais transformações dos produtos imobiliários residenciais no Distrito Sede de Florianópolis, a partir do estudo de três tipologias: loteamentos, condomínios horizontais e condomínios verticais, no período compreendido entre 1981 e 2010.
A partir da produção imobiliária residencial, procurou entender como as transformações mais gerais do sistema socioeconômico modificam - mas também se adaptam - ao tocarem territórios concretos, repletos de história, de conflitos e de interesses não necessariamente alinhados entre si.
A pesquisa parte da hipótese de que nas últimas décadas os produtos imobiliários residenciais sofreram transformações importantes, em parte como respostas às mudanças no metabolismo do capitalismo em sua versão neoliberal e financeirizada; em parte condicionada por aspectos específicos de Florianópolis: seu território, seus agentes, suas instituições, seus conflitos e relações de poder.Programa de Educação Tutorial - PET. FNDE/MDE
Oral treatment with Saccharomyces cerevisiae strain UFMG 905 modulates immune responses and interferes with signal pathways involved in the activation of inflammation in a murine model of typhoid fever
AbstractSalmonella spp. are Gram-negative, facultative, intracellular pathogens that cause several diarrheal diseases ranging from self-limiting gastroenteritis to typhoid fever. Previous results from our laboratory showed that Saccharomyces cerevisiae strain UFMG 905 isolated from ‘cachaça’ production presented probiotic properties due to its ability to protect against experimental infection with Salmonella enterica serovar Typhimurium. In this study, the effects of oral treatment with S. cerevisiae 905 were evaluated at the immunological level in a murine model of typhoid fever. Treatment with S. cerevisiae 905 inhibited weight loss and increased survival rate after Salmonella challenge. Immunological data demonstrated that S. cerevisiae 905 decreased levels of proinflammatory cytokines and modulated the activation of mitogen-activated protein kinases (p38 and JNK, but not ERK1/2), NF-κB and AP-1, signaling pathways which are involved in the transcriptional activation of proinflammatory mediators. Experiments in germ-free mice revealed that probiotic effects were due, at least in part, to the binding of Salmonella to the yeast. In conclusion, S. cerevisiae 905 acts as a potential new biotherapy against S. Typhimurium infection due to its ability to bind bacteria and modulate signaling pathways involved in the activation of inflammation in a murine model of typhoid fever
d-alpha Correlation functions and collective motion in Xe+Au collisions at E/A=50 MeV
The interplay of the effects of geometry and collective motion on d-
correlation functions is investigated for central Xe+Au collisions at E/A=50
MeV. The data cannot be explained without collective motion, which could be
partly along the beam axis. A semi-quantitative description of the data can be
obtained using a Monte-Carlo model, where thermal emission is superimposed on
collective motion. Both the emission volume and the competition between the
thermal and collective motion influence significantly the shape of the
correlation function, motivating new strategies for extending intensity
interferometry studies to massive particles.Comment: Accepted for publication on Physics Letters
The Milky Way Bulge: Observed properties and a comparison to external galaxies
The Milky Way bulge offers a unique opportunity to investigate in detail the
role that different processes such as dynamical instabilities, hierarchical
merging, and dissipational collapse may have played in the history of the
Galaxy formation and evolution based on its resolved stellar population
properties. Large observation programmes and surveys of the bulge are providing
for the first time a look into the global view of the Milky Way bulge that can
be compared with the bulges of other galaxies, and be used as a template for
detailed comparison with models. The Milky Way has been shown to have a
box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an
additional spheroidal component. In this review we summarise the global
chemical abundances, kinematics and structural properties that allow us to
disentangle these multiple components and provide constraints to understand
their origin. The investigation of both detailed and global properties of the
bulge now provide us with the opportunity to characterise the bulge as observed
in models, and to place the mixed component bulge scenario in the general
context of external galaxies. When writing this review, we considered the
perspectives of researchers working with the Milky Way and researchers working
with external galaxies. It is an attempt to approach both communities for a
fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure
- …