Design and validation of the soccer tactical knowledge test (STKT)

El propósito de este estudio fue determinar la validez de un test de evaluación del conocimiento táctico en fútbol. Siete expertos revisaron el instrumento y 465 niños/as de entre 8-14 años fueron encuestados. El 100% de acuerdo entre los expertos, la consistencia interna (α=.87), la correlación Testretest (r=.75) y la correlación entre el conocimiento táctico y el criterio externo de entrenadores de fútbol (p<.01), sugirieron que el instrumento era fiable. El contexto deportivo se mostró determinante sobre el nivel de conocimiento táctico (p<.01) apoyando la validez de constructo y concurrente. Estos resultados confirmaron la validez del instrumento para evaluar el conocimiento táctico en fútbol de jóvenes que se inician a los deportes de equipoThe purpose of the present study was to determine the validity of a tactical knowledge assessment test in soccer. Seven experts reviewed the instrument and 465 children aged 8 to 14 years completed the test. The experts’ opinion (100% agreement), internal consistency (α=.87), Test-retest correlation (r=.75), and the correlations between the soccer tactical knowledge and the external criterion of soccer coaches (r=.46, p<.01), showed reasonable evidence for assessing the test reliability. The sport context was determinant on the tactical knowledge (p<.01), supporting construct and concurrent validity. These results verify the validity of this instrument for assessing soccer tactical knowledge in young beginners who are starting to practice team sport

The Double Quasar HE1104-1805: a case study for time delay determination with poorly sampled lightcurves

We present a new determination of the time delay of the gravitational lens system HE1104-1805 ('Double Hamburger') based on a previously unpublished dataset. We argue that the previously published value of dt_(A-B)=0.73 years was affected by a bias of the employed method. We determine a new value of dt_(A-B)=0.85+/-0.05 years (2 sigma confidence level), using six different techniques based on non interpolation methods in the time domain. The result demonstrates that even in the case of poorly sampled lightcurves, useful information can be obtained with regard to the time delay. The error estimates were calculated through Monte Carlo simulations. With two already existing models for the lens and using its recently determined redshift, we infer a range of values of the Hubble parameter: Ho=48+/-4 km/s Mpc^-1 (2 sigma) for a singular isothermal ellipsoid (SIE) and Ho=62+/-4 km/s Mpc^-1 (2 sigma) for a constant mass-to-light ratio plus shear model (M/L+gamma). The possibly much larger errors due to systematic uncertainties in modeling the lens potential are not included in this error estimate.Comment: 11 pages, 15 figures, accepted by Astronomy and Astrophysic

Surface phosphorylation of chitosan significantly improves osteoblast cell viability, attachment and proliferation

Chitosan biocompatibility is often associated with the structural similarities with glycosaminoglycans (GAGs). Although all of the GAGs are built from repeating disaccharide units and some of them contain N-glucosamine (the main hexosamine in the chitosan backbone), all of them also contain negatively charged functional groups. These charged units are believed to have a crucial role for the formation of proteoglycans and hence for key biochemical processes/signaling related to cell functionality and survival. Lack of these groups in chitosan structure could be the reason for the previously observed poor cell adhesion to this material. Herein, we report that plasma induced grafting of negatively charged phosphonic groups can induce remarkably distinguishable cell response and significantly improve the adhesion, proliferation and viability of osteoblast cells. The proposed plasma induced polymerization is a very simple and versatile method and can be easily adapted to other materials and different negatively charged units.The authors acknowledge funding from EU Marie Curie Actions, Alea Jacta Est (MEST-CT-2004-008104) and Portuguese Foundation for Science and Technology (FCT)(SFRH/BPD/34545/2007). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Silicon-hydroxyapatite bioactive coatings (Si-HA) from diatomaceous earth and SiO2: study of adhesion and proliferation of osteoblast-like cells

The aim of this study consisted of investigating the influence of bioactive ceramic coatings of silicon substituted hydroxyapatite (Si-HA) over the behaviour of the human osteoblast-like cell (SaOS-2) line. Pulsed laser deposition (PLD) was the selected technique to deposit the coatings over titanium substrates. Diatomaceous earth and SiO2, together with commercial hydroxyapatite were respectively the silicon and HA sources used to produce the Si-HA coatings. HA coatings with 0% of silicon were used as control of the experiment. [...]info:eu-repo/semantics/publishedVersio

The Bartonian-Priabonian marine record of the eastern South Pyrenean foreland basin (NE Spain): a new calibration of the larger foraminifers and calcareous nannofossil biozonation

This study presents a combined biostratigraphic (calcareous nannofossils, larger foraminifers) and magnetostratigraphic study of the Middle and Late Eocene marine units of the Igualada area, eastern Ebro Basin. The studied sections of Santa Maria de Miralles and La Tossa encompass the complete marine succession of the Santa Maria Group, where assemblages rich in larger foraminifers have been studied since the early 1950’s. A total of 224 paleomagnetic sites and 62 biostratigraphic samples were collected along a 1350m-thick section that ranges from chron C20n to chron C16n (∼43Ma to ∼36Ma). The resulting magnetostratigraphy-based chronology challenges existing chronostratigraphic interpretations of these units and results in a new calibration of the biostratigraphic zonations. The base of calcareous nannofossil Zone NP19-20 is pinned down to an older age than its presently accepted attribution, whereas the time span assigned to Zone NP18 is significantly reduced. A revised calibration of larger foraminifers indicates that Zone SBZ18, formerly assigned exclusively to the late Bartonian, extends its range to the earlymost Priabonian, the Bartonian stage being almost entirely represented by Zone SBZ17. A division of Zone SBZ18 into two subzones is proposed

Shape-invariant quantum Hamiltonian with position-dependent effective mass through second order supersymmetry

Second order supersymmetric approach is taken to the system describing motion of a quantum particle in a potential endowed with position-dependent effective mass. It is shown that the intertwining relations between second order partner Hamiltonians may be exploited to obtain a simple shape-invariant condition. Indeed a novel relation between potential and mass functions is derived, which leads to a class of exactly solvable model. As an illustration of our procedure, two examples are given for which one obtains whole spectra algebraically. Both shape-invariant potentials exhibit harmonic-oscillator-like or singular-oscillator-like spectra depending on the values of the shape-invariant parameter.Comment: 16 pages, 5 figs; Present e-mail of AG: [email protected]

Nutritional problems perceived by pediatricians in Spanish children younger than 3 years

Introducción: Los padres son los principales responsables de la educación nutricional de sus hijos y es labor del pediatra orientar y resolver problemas al respecto. En este estudio se pretende conocer la relevancia de las cuestiones nutricionales en la consulta del pediatra y los principales problemas nutricionales percibidos en los menores de 3 años. Métodos: Estudio descriptivo, transversal en dos fases. La primera consistió en entrevistas y grupos de discusión con 30 pediatras seleccionados aleatoriamente en Madrid y Barcelona. Los resultados se utilizaron para diseñar el cuestionario online (76 preguntas relacionadas con la nutrición en niños de 0-3 años) de la siguiente fase, en la que participaron pediatras seleccionados de forma aleatoria y representativa del territorio nacional. Resultados: De 258 pediatras seleccionados, completaron el cuestionario 151, que atendían a una media de 588 pacientes/mes. Los principales problemas nutricionales percibidos hasta los 12 meses fueron las deficiencias de hierro y vitaminas y la escasa ganancia de peso, y posteriormente la ingesta excesiva de carbohidratos y lípidos y el sobrepeso. Los padres fueron considerados los actores principales en la salud nutricional de sus hijos, pero su preocupación por esta cuestión se reduce significativamente (p < 0,0001) con la edad del niño. Los aspectos considerados más importantes para obtener unos buenos hábitos alimentarios fueron la alimentación adaptada a las necesidades del niño y respetar el tiempo de sueño. El porcentaje de pacientes que recibe recomendaciones de hábitos nutricionales varió del 88% (0-6 meses) al 61% (24-36 meses). Conclusiones: A pesar de considerar la salud nutricional importante, la intervención educativa del pediatra al respecto no es óptima. Los problemas nutricionales percibidos fueron distintos según la edadIntroduction: Parents are most responsible for nutritional education of children, and pediatritians must advise and help them with their doubts. The purpose of this study was to know the relevance of nutritional topics in daily practice and the main nutritional problems perceived by pediatritians in children under 3 years of age. Methods: Descriptive, cross-sectional study performed in 2 stages. First stage consisted on discussion meetings with 30 random-selected pediatritians from Madrid and Barcelona. Results were used to design the on-line questionnaire of the second stage (76 questions related to nutrition in children under 3 years). A random and representative sample of Spanish pediatritians was selected for this stage. Results: One hundred and fifty one pediatritians, among 258 sampled, completed the questionnaire. They referred to see a mean of 588 patients/month. The main perceived nutritional problems in the first year of life were iron and vitamin deficiencies and poor weight gain. In the next months, excess in carbohydrates and lipid intake and overweight were the main problems perceived. Parents were considered the main actors regarding their children’s nutritional health, but their concern in these questions significantly reduced with children’s age (p < 0,0001). Factors considered to have the greatest relevance in the acquisition of good nutritional habits were to provide a diet adjusted for children’s requirements and to observe the appropriate sleeping hours. The proportion of children who receive nutritional counseling varied from 88% (0-6 months) to 61% (24-36 months). Conclusions: Despite of the relevance given by pediatritians, educational intervention regarding nutritional health is not ideal. Nutritional problems perceived by pediatritians varied with children’s ageEste estudio ha sido financiado por Almiron/Danone Baby Nutrition

Conductance oscillations of a spin-orbit stripe with polarized contacts

We investigate the linear conductance of a stripe of spin-orbit interaction in a 2D electron gas; that is, a 2D region of length $\ell$ along the transport direction and infinite in the transverse one in which a spin-orbit interaction of Rashba type is present. Polarization in the contacts is described by means of Zeeman fields. Our model predicts two types of conductance oscillations: Ramsauer oscillations in the minority spin transmission, when both spins can propagate, and Fano oscillations when only one spin propagates. The latter are due to the spin-orbit coupling with quasibound states of the non propagating spin. In the case of polarized contacts in antiparallel configuration Fano-like oscillations of the conductance are still made possible by the spin orbit coupling, even though no spin component is bound by the contacts. To describe these behaviors we propose a simplified model based on an ansatz wave function. In general, we find that the contribution for vanishing transverse momentum dominates and defines the conductance oscillations. Regarding the oscillations with Rashba coupling intensity, our model confirms the spin transistor behavior, but only for high degrees of polarization. Including a position dependent effective mass yields additional oscillations due to the mass jumps at the interfaces.Comment: 8.5 pages, 9 figure

Relación del conocimiento táctico de jóvenes futbolistas con la edad, la experiencia y el nivel de pericia

Dada la importancia del conocimiento previo para decidir de forma adaptable en el deporte, se estudió el conocimiento táctico de 109 jóvenes futbolistas de ocho a doce años y su relación con la edad, la experiencia y el nivel de pericia, mediante el Test de Conocimiento TácticoOfensivo en Fútbol. Se observaron diferencias significativas de magnitud moderada en función de la edad y la experiencia en competición federada de los jugadores (p &lt; ,05; r &lt; ,40), aunque los resultados fueron dispares. El nivel de pericia correlacionó significativamente con los conocimientos declarativo (rho = ,350; p &lt; ,01), procedimental (rho = ,446; p &lt; ,01) y táctico de los jugadores (rho = ,446; p &lt; ,01). Los hallazgos sugieren que la edad y experiencia no tienen un papel tan determinante sobre el conocimiento táctico como otras variables: metodologías de enseñanza recibidas o la formación del entrenador. Se necesitan estudios en los que se analice si la formación específica en el conocimiento de los problemas tácticos mejora la habilidad de toma de decisiones en el deporte en general y en el fútbolbase en particular

The GUAPOS project: G31.41+0.31 Unbiased ALMA sPectral Observational Survey. IV. Phosphorus-bearing molecules and their relation with shock tracers

The astrochemistry of the important biogenic element phosphorus (P) is still poorly understood, but observational evidence indicates that P-bearing molecules are likely associated with shocks. We study P-bearing molecules, as well as some shock tracers, towards one of the chemically richest hot molecular core, G31.41+0.31, in the framework of the project "G31.41+0.31 Unbiased ALMA sPectral Observational Survey" (GUAPOS), observed with the Atacama Large Millimeter Array (ALMA). We have observed the molecules PN, PO, SO, SO2, SiO, and SiS, through their rotational lines in the spectral range 84.05-115.91 GHz, covered by the GUAPOS project. PN is clearly detected while PO is tentatively detected. The PN emission arises from two regions southwest of the hot core peak, "1" and "2", and is undetected or tentatively detected towards the hot core peak. the PN and SiO lines are very similar both in spatial emission morphology and spectral shape. Region "1" is in part overlapping with the hot core and it is warmer than region "2", which is well separated from the hot core and located along the outflows identified in previous studies. The column density ratio SiO/PN remains constant in regions "1" and "2", while SO/PN, SiS/PN, and SO2/PN decrease by about an order of magnitude from region "1" to region "2", indicating that SiO and PN have a common origin even in regions with different physical conditions. Our study firmly confirms previous observational evidence that PN emission is tightly associated with SiO and it is likely a product of shock-chemistry, as the lack of a clear detection of PN towards the hot-core allows to rule out relevant formation pathways in hot gas. We propose the PN emitting region "2" as a new astrophysical laboratory for shock-chemistry studiesComment: 15 pages, 11 figures, accepted for publication in A&