"No-Scalar-Hair" Theorems for Nonminimally Coupled Fields with Quartic Self-Interaction

Self-gravitating scalar fields with nonminimal coupling to gravity and having a quartic self-interaction are considered in the domain of outer communications of a static black hole. It is shown that there is no value of the nonminimal coupling parameter $\zeta$ for which nontrivial static black hole solutions exist. This result establishes the correctness of Bekenstein ``no-scalar-hair'' conjecture for quartic self-interactions.Comment: 8 pages, RevTeX

Scalar Fields Nonminimally Coupled to pp Waves

Here, we report pp waves configurations of three-dimensional gravity for which a scalar field nonminimally coupled to them acts as a source. In absence of self-interaction the solutions are gravitational plane waves with a profile fixed in terms of the scalar wave. In the self-interacting case, only power-law potentials parameterized by the nonminimal coupling constant are allowed by the field equations. In contrast with the free case the self-interacting scalar field does not behave like a wave since it depends only on the wave-front coordinate. We address the same problem when gravitation is governed by topologically massive gravity and the source is a free scalar field. From the pp waves derived in this case, we obtain at the zero topological mass limit, new pp wave solutions of conformal gravity for any arbitrary value of the nonminimal coupling parameter. Finally, we extend these solutions to the self-interacting case of conformal gravity.Comment: 14 pages, RevTeX. Minor changes. To appear in Phys. Rev.

Stability properties of black holes in self-gravitating nonlinear electrodynamics

We analyze the dynamical stability of black hole solutions in self-gravitating nonlinear electrodynamics with respect to arbitrary linear fluctuations of the metric and the electromagnetic field. In particular, we derive simple conditions on the electromagnetic Lagrangian which imply linear stability in the domain of outer communication. We show that these conditions hold for several of the regular black hole solutions found by Ayon-Beato and Garcia.Comment: 15 pages, no figure

Terapia regenerativa en tendones y células madres en medicina equina

Se ha realizado extensa investigación clínica con células madre en el equino, siendo una fuente de estudios vanguardistas en medicina veterinaria, así como un modelo animal excepcional. Esto ha ayudado a obtener una amplia perspectiva sobre las aplicaciones de estas técnicas en medicina humana. Aunque la mejora perceptible se han obtenido en el frente clínica, la caracterización in vitro de las células madre de equino se encuentra todavía en una etapa temprana. Para explicar los resultados favorables de la terapia de células madre clínica en el caballo, los avances se deben enfocar en la caracterización de las células madre equinas. Las lesiones tendinosas afectan frecuentemente a los caballos deportivos y representan una pérdida significativa para la industria equina. La acumulación de micro-daños dentro de la arquitectura del tendón conduce a la formación de las lesiones centrales. Los antecedentes sobre por qué estos tratamientos han sido incentivados, los datos de su uso experimental y los resultados del actual uso clínico en los caballos tratados con células madre, se presentan junto con los retos de futuro de la terapia con células madre para la comunidad veterinaria

Manipulation of exercise to rest ratio within set duration on physical and technical outcomes during small-sided games in elite youth soccer players

Training practices for elite soccer players should take into account specific technical, tactical and physical components. As a consequence of these demands small-sided games (SSGs) have become a popular conditioning tool that replicate the demands encountered during match play. The aim of this investigation was to examine how the manipulation of exercise to rest ratio, within the same overall duration, affected both physical and technical outcomes during SSGs in elite youth soccer. Twelve elite youth soccer players participated in three variations of eight minute 6v6 SSGs. The three variations included eight minutes continuous, 2 × 4 min and 4 × 2 min. Players perceived the continuous 8 min block as the hardest (4.5 ± 1.5 AU), followed by the 2 × 4 min (3.9 ± 1.4 AU) and the 4 × 2 min (3.3 ± 1.4 AU), although no difference in mean HR or physical measures via GPS analysis between SSGs was evident. From the technical perspective, only goals scored reached significance, with post hoc analysis identifying the number of goals scored were significantly higher during the 4 × 2 min and 2 × 4 min SSGs compared to 8 min continuous block. These results show that subjective ratings of exertion differed between conditions, but only minor technical manipulations were observed by adjusting work to rest ratios, with no significant effect on physical performance

Síndrome cerebelar por vacuolización neuronal y degeneración espinocerebelar en Rottweiler : primer caso descrito en España

Se presenta un caso clínico de síndrome cerebelar en un Rottweiler hembra joven

Regular Magnetic Black Holes and Monopoles from Nonlinear Electrodynamics

It is shown that general relativity coupled to nonlinear electrodynamics (NED) with the Lagrangian $L(F)$, $F = F_mn F^mn$ having a correct weak field limit, leads to nontrivial static, spherically symmetric solutions with a globally regular metric if and only if the electric charge is zero and $L(F)$ tends to a finite limit as $F \to \infty$. Properties and examples of such solutions, which include magnetic black holes and soliton-like objects (monopoles), are discussed. Magnetic solutions are compared with their electric counterparts. A duality between solutions of different theories specified in two alternative formulations of NED (called $FP$ duality) is used as a tool for this comparison.Comment: 6 pages, Latex2e. One more theorem, some comments and two references have been added. Final journal versio

Effects of flywheel training on strength-related variables in female populations. A systematic review

This study aimed to evaluate the effect of flywheel training on female populations, report practical recommendations for practitioners based on the currently available evidence, underline the limitations of current literature, and establish future research directions. Studies were searched through the electronic databases (PubMed, SPORTDiscus, and Web of Science) following the preferred reporting items for systematic reviews and meta-analysis statement guidelines. The methodological quality of the seven studies included in this review ranged from 10 to 19 points (good to excellent), with an average score of 14-points (good). These studies were carried out between 2004 and 2019 and comprised a total of 100 female participants. The training duration ranged from 5 weeks to 24 weeks, with volume ranging from 1 to 4 sets and 7 to 12 repetitions, and frequency ranged from 1 to 3 times a week. The contemporary literature suggests that flywheel training is a safe and time-effective strategy to enhance physical outcomes with young and elderly females. With this information, practitioners may be inclined to prescribe flywheel training as an effective countermeasure for injuries or falls and as potent stimulus for physical enhancement

KINEMATICS ANALYSIS OF POLE VAULT DURING NATIONAL INDOOR ATHLETICS CHAMPIONSHIPS

There should be a minimal level of individual variation presented by athletes in high level competitions, reflecting a high degree of consistency in the form of execution. By registering and subsequently analysing kinematic and kinetic data, obtained during athletic exercises, it is possible to verify such differences. The objective of this work was to collect kinematic data in order to quantify and verify these differences. Parameters such as amplitude, frequency, velocity, inter-segmental angles and kinetic energy were quantified, in order to understand the variations found in the different parameters. One should assume that an athlete that presents major variations from the above-mentioned parameters is not at his or her best form. We analysed 16 exercises of 3 athletes in the Portugal Indoor Championship in the year of the Sydney Olympic Games. This analysis enabled trainers to gain access to information on stability of technique in the exercise of each jump