The relationship between running distance and coaches' perception of team performance in professional soccer player during multiple seasons.

This study analyzed how the physical movement profile of soccer matches evolved throughout a season by assessing the variability of different metrics depending on the season phase. In addition, the evolution of running distances was investigated in the relation to the team performance based on the coaches' perception. Games from four consecutives Spanish LaLiga seasons (n = 1520) were recorded using an optical tracking system (i.e., ChyronHego). Total distance (TD), distance covered between 14 and 21 km h-1 (MIRD), 21-24 km h-1 (HIRD), and > 24 km h-1 (VHIRD) were analyzed, as well as the number of efforts between 21 and 24 km h-1 (Sp21) and > 24 km h-1 (Sp24). Seasons were divided into four phases (P): P1 (matches 1-10), P2 (11-19), P3 (20-29), and P4 (30-38). Linear mixed models revealed that soccer players covered significantly greater distances and completed a higher number of sprints in P2 and P3. Also, team performance evaluated by soccer coaches was positively related to TD, HIRD, VHIRD and Sp21 in P1. A negative relationship was observed between team performance and distance covered at speeds below 21 km h-1 in P2 and P3. Team performance was negatively related to TD, MIRD, and HIRD, and Sp21 in P4. As conclusion, the team performance perceived by coaches is related to the movement profile throughout a season, and it significantly influences the evolution of soccer players' movement profiles. Specifically, it seems that the players of the best teams have the best physical performance at the beginning of the season with respect to the rest of the phases.

Physical exercise in young patients with congenital heart disease.

The aim of this paper is to clarify two important aspects about patients affected by congenital heart disease. Their functional status plays a dominant role in the definition of quality of life related to health status, because of its implication in working and recreational activities. In the first part, we explain their cardiovascular adaptation on exercise, based on pathology (Tetralogy of Fallot, transposition of great arteries, univentricular heart). In the second part, we explain the risk of sudden death from congenital heart disease due to exercise, because of electrical cardiac instability and/or the structural abnormalities of the cardiovascular parietal walls.

Dielectric anomalies in ferroelectric nanostructures.

First-principles-based methods are used to determine the external dielectric susceptibility (i.e., the polarization response to the external electric field) and the internal susceptibility (i.e., the polarization response to the average internal field) in ferroelectric dots, wires, and films, as a function of the electrical boundary conditions. While the external susceptibility is obviously positive, we find that the internal one is negative over a wide range of boundary conditions for all kinds of nanostructures. A Landau-type phenomenological model provides a rationale for all of our findings.

Orbital magnetization in periodic insulators.

Working in the Wannier representation, we derive an expression for the orbital magnetization of a periodic insulator. The magnetization is shown to be comprised of two contributions, an obvious one associated with the internal circulation of bulklike Wannier functions in the interior, and an unexpected one arising from net currents carried by Wannier functions near the surface. Each contribution can be expressed as a bulk property in terms of Bloch functions in a gauge-invariant way. Our expression is verified by comparing numerical tight-binding calculations for finite and periodic samples.

Orbital magnetization in extended systems.

While the orbital magnetic dipole moment of any finite sample is well-defined, it becomes ill-defined in the thermodynamic limit as a result of the unboundedness of the position operator. Effects due to surface currents and to bulk magnetization are not easily disentangled. The corresponding electrical problem, where surface charges and bulk polarization appear as entangled, was solved about a decade ago by the modern theory of polarization, based on a Berry phase. We follow a similar path here, making progress toward a bulk expression for the orbital magnetization in an insulator represented by a lattice-periodic Hamiltonian with broken time-reversal symmetry. We therefore limit ourselves to the case where the macroscopic (i.e. cell-averaged) magnetic field vanishes. We derive an expression for the contribution to the magnetization arising from the circulating currents internal to the bulk Wannier functions, and then transform to obtain a Brillouin zone integral involving the occupied Bloch orbitals. A version suitable for practical implementation in discretized reciprocal space is also derived, and the gauge invariance of both versions is explicitly shown. However, tests on a tight-binding model indicate the presence of additional edge currents, and it remains to be determined whether these can be related to the bulk band structure.

Single nucleotide polymorphism in prohibitin 3' untranslated region and breast-cancer susceptibility.

The RNA encoded by the 3' untranslated region of the prohibitin gene arrests cell proliferation by blocking the transition between the G1 and S phases of the cell cycle. The product of a variant allele (T allele) is inactive. We did a case-control study of prohibitin genotype in 205 women with breast cancer and 1046 healthy controls. The results showed an association between the T allele and breast cancer in women who reported a first-degree relative with the disease (odds ratio 2.5, p=0.005). An even stronger association was found in a subset of women diagnosed at or before age 50 years (4.8, p=0.003). These data suggest that prohibitin genotyping has value in assessing risk of breast cancer in women aged 50 years or younger with at least one first-degree relative with the disease.

Metabolites from apoptotic thymocytes inhibit thymopoiesis in adenosine deaminase-deficient fetal thymic organ cultures.

Murine fetal thymic organ culture was used to investigate the mechanism by which adenosine deaminase (ADA) deficiency causes T-cell immunodeficiency. C57BL/6 fetal thymuses treated with the specific ADA inhibitor 2'-deoxycoformycin exhibited features of the human disease, including accumulation of dATP and inhibition of S-adenosylhomocysteine hydrolase enzyme activity. Although T-cell receptor (TCR) Vbeta gene rearrangements and pre-TCR-alpha expression were normal in ADA-deficient cultures, the production of alphabeta TCR(+) thymocytes was inhibited by 95%, and differentiation was blocked beginning at the time of beta selection. In contrast, the production of gammadelta TCR(+) thymocytes was unaffected. Similar results were obtained using fetal thymuses from ADA gene-targeted mice. Differentiation and proliferation were preserved by the introduction of a bcl-2 transgene or disruption of the gene encoding apoptotic protease activating factor-1. The pan-caspase inhibitor carbobenzoxy-Val-Ala-Asp-fluoromethyl ketone also significantly lessened the effects of ADA deficiency and prevented the accumulation of dATP. Thus, ADA substrates accumulate and disrupt thymocyte development in ADA deficiency. These substrates derive from thymocytes that undergo apoptosis as a consequence of failing to pass developmental checkpoints, such as beta selection.

CD73 expression and fyn-dependent signaling on murine lymphocytes.

CD73 is a glycosyl phosphatidylinositol-anchored protein with both ecto-enzyme activity (ecto-5'-nucleotidase) and signal transducing capabilities for human T lymphocytes. We now report an analysis of the distribution and function of CD73 in murine lymphoid tissues made possible by the development of the first monoclonal antibodies (mAb) specific for murine CD73. Subsets of T and B lymphocytes are CD73+ and the level of expression increases with lymphocyte maturation in both species. Among B cells, CD73 is largely restricted to cells which have undergone isotype switching. The signal transmitting function of CD73 is also conserved, as splenic T cells treated with anti-CD73 mAb plus phorbol 12-myristate 13-acetate proliferate and secrete IL-2. Fyn-/- mice are unresponsive to CD73 ligation, however, demonstrating the requirement for this tyrosine kinase in CD73-mediated signal transduction. CD73 is down-regulated after mAb plus cross-linking, suggesting that expression may be controlled by interaction with a ligand. Only small numbers of thymocytes are CD73+, so CD73 receptor functions are unlikely to be important for developing T cells. However, immunohistochemical analysis reveals that reticular and vascular cells throughout the thymus and other lymphoid tissues are markedly CD73+. Therefore, CD73 might mediate lymphocyte-stromal cell interactions or condition the local microenvironment to facilitate lymphocyte development and/or function.