Efectos de un entrenamiento de fuerza de corta duración sobre la capacidad de salto vertical en jugadores de voleibol de elite durante la temporada

The aim of this study was to describe the effects of 6 weeks of combined strength and jump training which incorporated modera te loads and high intensity contractions on the vertical jump ability (VJ), loaded jumps and velocity of execution in full squat in a group of professional male volleyball players during the competition season. It was hypothesized that the VJ improved by cross combined strength and jump training both characterized by high velocity of execution (>1m/s). The participants in this study were twelve players who competed in the fir st national division of the Spanish National League during the 2011-2012 season. The neuromuscular performance was estimated by unloaded (CMJ) and load ed countermovement jumps (CMJ loaded ) height (cm); and by velocity of displacement in the concentric phase of full squat (FS) (m/s). There was a significant increase in CMJ and CMJ loaded after 6-week of training (5%, p<0.01; and 5.7%, p<0.05; respectively). These changes were accompanied by a small and moderate value of Effect Size (0.47, and 0.67; respectively). No significant differences were observed for velocity of displacement in FS. The linear correlation analysis showed a single moderate correlation statistically significant between the changes in CMJ-CMJ loaded and CMJ-FS (r=0.62 and r=0.59, p<0.05; respectively). Albeit speculative, our results suggest that the use of moderate loads could be enough to im prove the vertical jump performance, since in our study a load equivalent to 60% 1RM in the FS was not exceeded and jumping exercises were performed wi th light loads.El objetivo de este estudio fue describir los efectos de 6 semanas de entrenamiento combinado de fuerza y salto, el cual incorpora cargas moderadas e intensidades de contracción altas, sobre la capacidad de salto vertical, saltos con cargas y la velocidad de ejecución en el ejercicio de sentadilla en un grupo de jugadores profesionales de voleibol durante la temporada de competición. Se estableció la hipótesis de que el sa lto vertical mejoro por el uso combinado de entrenamiento de fuerza y salto, ambos caracterizados por una alta velocidad de ejecución (>1m/s). El rendimie nto neuromuscular fue estimado por la altura (cm) del salto sin cargas (CMJ), salto con cargas (CMJ loaded ), y por la velocidad (m/s) de desplazamiento en la fase concéntrica en la sentadilla completa (FS). Tuvo lugar un incremento significativo en CMJ y CMJ loaded después de 6 semanas de entrenamientos (5%, p<0.01; y 5.7%, p<0.05; respectivamente). Estos cambios fueron acompañados por un valor de Tamaño del Efecto pequeño y moderado (0.47, and 0.67 ; respectivamente). No se observaron diferencias significativas en la velocidad de desplazamiento en FS. El análisis de correlación lineal mostró una correlación moderada estadísticamente significativa entre los cambios en CMJ-CMJ loaded y CMJ-FS (r=0.62; y r=0.59, p<0.05; respectivamente). Aunque algo especulativo, nuestros resultados sugieren que el uso de cargas moderadas podría ser suficiente para mejorar el rendimiento del salto vertical, ya que en nuestro estudio no se excedió una carga equivalente al 60% de 1RM en FS y los ejercicios de saltos también fueron realizados con cargas ligeras

One- and two-photon scattering from generalized V-type atoms

The one- and two-photon scattering matrix S is obtained analytically for a one-dimensional waveguide and a point-like scatterer with N excited levels (generalized V -type atom). We argue that the two-photon scattering matrix contains sufficient information to distinguish between different level structures which are equivalent for single-photon scattering, such as a V -atom with N = 2 excited levels and two two-level systems. In particular, we show that the scattering with the V -type atom exhibits a destructive interference effect leading to two-photon Coupled-Resonator-Induced Transparency, where the nonlinear part of the two-photon scattering matrix vanishes when each incident photon fulfills a single-photon condition for transparency

Single photons by quenching the vacuum

Heisenberg's uncertainty principle implies that the quantum vacuum is not empty but fluctuates. These fluctuations can be converted into radiation through nonadiabatic changes in the Hamiltonian. Here, we discuss how to control this vacuum radiation, engineering a single-photon emitter out of a two-level system (2LS) ultrastrongly coupled to a finite-band waveguide in a vacuum state. More precisely, we show the 2LS nonlinearity shapes the vacuum radiation into a nonGaussian superposition of even and odd cat states. When the 2LS bare frequency lays within the band gaps, this emission can be well approximated by individual photons. This picture is confirmed by a characterization of the ground and bound states, and a study of the dynamics with matrix product states and polaron Hamiltonian methods.Comment: 9 pages, 10 figure

Determinant factors of pull up performance in trainedathletes

Aim: to investigate the relationship among pull up and lat pull exercises and differentanthropometric dimensions in trained athletes. Methods: twenty-five males were evaluated for maximum number of pull ups, one-repetitionmaximum lat pull (1RM Lat Pull), lat pull repetitions at 80% 1RM (Lat Pull at 80% 1RM), latpull repetitions at a load equivalent to body mass (Lat Pull at BM-load), and differentanthropometric variables. Furthermore, the subjects were divided in higher (HPG, n = 12) andlower pull up performance (LPG, n = 13) to compare the differences in the variables analyzedbetween both levels. Results: pull ups were significantly correlated with Lat Pull at BM-load (r = .62, P < .01) butneither with 1RM Lat Pull (r = .09) nor with Lat Pull at 80% 1RM (r = -.15). Pull ups showed asignificant (P < .05) negative relationship with body mass (BM, r = -.55), lean body mass(LBM, r = -.51), and fat mass (FM, r = -.52), while BM and LBM were significantly correlatedwith 1RM Lat Pull (r = .55, P < .05). HPG showed significantly (P < .05) lower BM (0/3/97%),FM (1/3/97%) and LBM (1/4/95%) than LPG. Furthermore, HPG attained significantly (P < .05– .001) greater performance in Lat Pull at BM-load (100/0/0%) and 1RM Lat Pull•BM-1(96/3/2%) than LPG. Conclusion: these findings suggest that pull up and lat pull exercises have common elements.Moreover, the anthropometric dimensions seem to influence differently on both exercises,depending on the strength indicator evaluated

Emergent Causality and the N-photon Scattering Matrix in Waveguide QED

In this work we discuss the emergence of approximate causality in a general setup from waveguide QED -i.e. a one-dimensional propagating field interacting with a scatterer. We prove that this emergent causality translates into a structure for the N-photon scattering matrix. Our work builds on the derivation of a Lieb-Robinson-type bound for continuous models and for all coupling strengths, as well as on several intermediate results, of which we highlight (i) the asymptotic independence of space-like separated wave packets, (ii) the proper definition of input and output scattering states, and (iii) the characterization of the ground state and correlations in the model. We illustrate our formal results by analyzing the two-photon scattering from a quantum impurity in the ultrastrong coupling regime, verifying the cluster decomposition and ground-state nature. Besides, we generalize the cluster decomposition if inelastic or Raman scattering occurs, finding the structure of the S-matrix in momentum space for linear dispersion relations. In this case, we compute the decay of the fluorescence (photon-photon correlations) caused by this S-matrix

The inorganic part of green roof substrates impacts differently on the growth of two Mediterranean plant species

[SPA] Los sustratos para cubiertas verdes deben reunir una serie de propiedades fisicoquímicas y nutricionales para poder ser usados como base para el desarrollo vegetal. El impacto de diversas dosis de materia orgánica así como del espesor del sustrato son factores ampliamente estudiados en este tipo de cubiertas. Sin embargo, el efecto de la parte inorgánica del sustrato sobre el crecimiento vegetal en este tipo de cubiertas no ha sido ampliamente estudiado. Para ello, se diseñaron cuatro sustratos compuestos por un 10% en volumen de compost mezclado con diversos materiales inorgánicos. Estas mezclas se dispusieron en mesas de cultivo con un espesor de 10 cm. En ellos, se sembraron dos especies vegetales típicas de la zona Mediterránea: Lotus creticus L. y Asteriscus maritimus L. Con el fin de estudiar la evolución de cada sustrato, se realizó un estudio de las propiedades fisicoquímicas, y nutricionales de cada sustrato. Se observaron mayores niveles de nutrientes en las mezclas con suelo que en aquellas que no lo presentaban (CB y CsB). Los resultados sugieren que una dosis de compost del 10% es capaz de mantener un aceptable desarrollo de ambas especies, aunque su comportamiento varía en función de la composición del sustrato. [ENG] Extensive green roofs substrates should meet a list of physicochemical and nutritional requirements to be used as a basis for plant growth. In recent years, the impact of different organic matter doses and the substrate depth on plant growth have been studied although little is known about the effect of the inorganic component of these substrates on plant development in Mediterranean green roof systems. Four substrates were made by mixing the same compost, at 10% by volume, with different inorganic materials. These were placed, with a depth of 10 cm on cultivation tables. Two endemic species were sown in each substrate: Lotus creticus L. and Asteriscus maritimus L. Physicochemical and nutritional properties of the substrates as well as the plant development were evaluated. We observed high levels of C and N in the soil-containing substrates than in the soilless ones (CB and CsB mixtures). The results suggest that a compost dose of 10% was able to maintain acceptable plant growth, but a different pattern was observed depending on the inorganic composition of the substrate.We thanks the INNPACTO project (IPT-2011-1017-310000) for the financial support. Authors are grateful to the Department of “Ingeniería Agromótica y del Mar” of the Polytechnic University of Cartagena for their assistance with the RSI ENVI 4.0 software

Combined strength and jump exercises training, effects on the vertical jump performance in a group of senior elite male volleyball players during a complete competition season

Se ha sugerido que para mejorar el rendimiento en el salto vertical (SV), los jugadores de voleibol deben realizar entrenamie nto con cargas específico para voleibol. Este estudio examina los efectos del entrenamiento combinado de fuerza y ejercicios de saltos sobre el rendimiento en el SV, en un grupo de alto nivel de jugadores de voleibol durante una temporada completa de la competición. Doce jugadores profesional es de voleibol participaron en este estudio. El rendimiento se midió mediante la altura (cm) del salto sin carga (CMJ) y con carga (CMJ loaded ), y por la velocidad de desplazamiento en fase concéntrica de la sentadilla completa (FS) (m/s). El entrenamiento tuvo lugar 2 días/semana, 16 semanas (2 ciclos / 8 semanas, 1 semana de descanso). Los ejercicios de resistencia fueron: FS, 3-4 series / 4-6 repeticiones, 50% al 65% de 1RM; cargada de f uerza, 3 series / 4-6 repeticiones, con máxima carga que permite ejecución técnica correcta; saltos con carga, 3-4 series / 4-5 repeticiones, 50%-80% carga con la que alcanzaron una altura de unos 20 cm.; salto sin carga, 3-4 series / 5 repeticiones. Hubo un aumento significativo en CMJ y CMJl oaded (7.12% y 9.78%; p .05). Nuestros resultados sugieren que el uso de cargas moderadas podría producir resultados similares en el rendimiento del SV al uso de cargas elevadas, ya que en nuestro estudio no superamos una carga equivalente al 65% de 1RM en el FS y los ejercicios de salto se realizaron con cargas ligeras. Estos resultados indican que la especificidad d el entrenamiento, expresada por la proximidad de las velocidades de ejecución de los ejercicios de entrenamiento a la velocidad de ejecución del SV, es de terminante para el rendimiento.It has been suggested that to improve vertical jump performance, volleyball players must complete specific volleyball resistance training. This study examines the effects of combined strength and jump exercises training on the vertical jump performance, in a group of sen ior elite male volleyball players during a full competition season. Twelve professional male volleyball players took part in this study . Players competed in the first national division of the Spanish National League during the 2014-2015 season . The performance was estimated by unloaded (CMJ), loaded countermovement jumps (CMJ loaded ) height (cm) and by velocity of displacement in the concentric phase of full squat (FS) (m•s -1 ). Training took place 2 days/week, 16 weeks (2 cycles/8 weeks, 1 week recovery). The resistance exercises were: FS, 3-4 series/4-6 repetitions, load from 50%-65% 1RM ; hang power clean, 3 series/4-6 repetitions with the maximum load that allows a correct technical execution; loaded jump, 3-4 series/4-5 repetitio ns, load from 50%-80% according to the weight with which the athletes reached a height of about 20 cm.; unloaded jump, 3-4 series/5 repetitions. Ther e was a significant increase in CMJ and CMJloaded (7.12% and 9.78%; p.05) . Our results suggest that the use of moderate loads could produce similar results on vertical jump performance to the use of high loads, since in ou r study a load equivalent to 65% 1RM in the FS was not exceeded and jumping exercises were performed with light loads. These results indicate that the sp ecificity of training, which in this case is expressed by the proximity of the velocities of execution of the training exercises to the velocity of ex ecution of the vertical jump, is determinant for the performance

Interactivity features on online newspapers: from a facsimile model to a multimedia one.

The purpose of this article is to know the current interactivity options in online newspapers. To do this, we analyze the concept of (structural) interactivity and establish a measuring tool based on some previous methodologies. This model includes a classification of newspapers into stages of development. In this way, we provide a tool, which allows media firms to know the degree of interactivity in newspapers, assessing what dimensions and parameters are being incorporated. It was applied to a sample of 21 online newspapers. Results show poor implementation of participation and customization options. There is a niche to be covered by sections of user-generated content and closer collaboration journalists-citizens. It will require a real adaptation to the new possibilities of interaction with readers at different levels of involvement and participation. The majority of newspapers are classified in a digital stage and some of them are close to the multimedia phase