Mechanisms of Action and Targets of Nitric Oxide in the Oculomotor System

Nitric oxide (NO) production by neurons in the prepositus hypoglossi (PH) nucleus is necessary for the normal performance of eye movements in alert animals. In this study, the mechanism(s) of action of NO in the oculomotor system has been investigated. Spontaneous and vestibularly induced eye movements were recorded in alert cats before and after microinjections in the PH nucleus of drugs affecting the NO–cGMP pathway. The cellular sources and targets of NO were also studied by immunohistochemical detection of neuronal NO synthase (NOS) and NO-sensitive guanylyl cyclase, respectively. Injections of NOS inhibitors produced alterations of eye velocity, but not of eye position, for both spontaneous and vestibularly induced eye movements, suggesting that NO produced by PH neurons is involved in the processing of velocity signals but not in the eye position generation. The effect of neuronal NO is probably exerted on a rich cGMP-producing neuropil dorsal to the nitrergic somas in the PH nucleus. On the other hand, local injections of NO donors or 8-Br-cGMP produced alterations of eye velocity during both spontaneous eye movements and vestibulo-ocular reflex (VOR), as well as changes in eye position generation exclusively during spontaneous eye movements. The target of this additional effect of exogenous NO is probably a well defined group of NO-sensitive cGMP-producing neurons located between the PH and the medial vestibular nuclei. These cells could be involved in the generation of eye position signals during spontaneous eye movements but not during the VOR.Fondo de Investigación Sanitaria Grants 94/0388 and 97/2054Comunidad Autónoma de Madrid Grant 08.5/0019/1997Dirección General de Investigación Científica y Technológica Grant PB 93–117

Gender diversity in the board, women’s leadership and business performance

Purpose: This paper investigates how gender diversity in top management—i.e., boardroom and top management positions—impacts business performance among Colombian public businesses. Design/methodology/approach: Building on the Upper Echelon theory which emphasizes that gender in an important characteristic that influences top management’s decision making, we employ panel data models on a sample of 54 Colombian public businesses for the period 2008-2015 to test the proposed hypotheses relating gender diversity and subsequent business performance. Findings: The results support that gender diversity is positively associated with subsequent business performance. More concretely, we find that the relationship between gender diversity at the top of the corporate hierarchy—in our case, as CEO and in the top management team—and subsequent performance becomes more evident when performance is linked to business operations (ROA), while the positive effect of women’s representation in the boardroom and subsequent performance is significant when performance is measured via shareholder-oriented metrics (ROE). Originality/value: Few studies have addressed the role of gender diversity on performance in developing economies. This study contributes to better understand how gender diversity impacts performance in contexts where women are underrepresented in the top management, and where the appointment of women directors or managers is not driven by regulatory pressures.Peer ReviewedPostprint (author's final draft

Path Integral approach to nonequilibrium potentials in multiplicative Langevin dynamics

We present a path integral formalism to compute potentials for nonequilibrium steady states, reached by a multiplicative stochastic dynamics. We develop a weak-noise expansion, which allows the explicit evaluation of the potential in arbitrary dimensions and for any stochastic prescription. We apply this general formalism to study noise-induced phase transitions. We focus on a class of multiplicative stochastic lattice models and compute the steady state phase diagram in terms of the noise intensity and the lattice coupling. We obtain, under appropriate conditions, an ordered phase induced by noise. By computing entropy production, we show that microscopic irreversibility is a necessary condition to develop noise-induced phase transitions. This property of the nonequilibrium stationary state has no relation with the initial stages of the dynamical evolution, in contrast with previous interpretations, based on the short-time evolution of the order parameter.Comment: 6 pages, 1 figure. Final version accepted for publication in EP

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

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

Seismic assessment of the masonry buildings typical of Barcelona using the Risk-UE methodology

En este trabajo se realiza un estudio para evaluar la vulnerabilidad y el daño sísmico en edificios de obra de fábrica de ladrillo no reforzada. Se han elegido 3 modelos de edificios representativos del distrito Eixample de Barcelona. El análisis de la vulnerabilidad sísmica se lleva a cabo mediante la metodología Risk-UE. La demanda sísmica se define a partir del espectro de proyecto elástico con 5% de amortiguamiento, definido, en este caso, por el Eurocódigo 8. Las curvas de fragilidad se obtienen a partir de un análisis no lineal, teniendo en cuenta los espectros de capacidad. El daño sísmico esperado se consigue con las matrices de probabilidad de daño, las cuales indican la probabilidad de ocurrencia de un estado de daño para una demanda sísmica específica. La modelización de los edificios se realiza con el programa TreMuri mediante un modelo de macroelementos, el cual representa las paredes de los edificios. Los edificios aquí analizados son reales y se dispuso de planos e informes específicos. Los resultados obtenidos muestran una vulnerabilidad importante en este tipo de edificios, teniendo en cuenta el escenario sísmico considerado el daño sísmico esperado es alto.In this work, a study about the vulnerability and seismic damage of unreinforced masonry buildings is carried out. Three models of buildings representatives of the Eixample district of Barcelona have been chosen. The seismic vulnerability is evaluated by means of the Risk-UE methodology. The seismic demand is described by elastic project spectrum, in this case, defined by the Eurocode 8. Fragility curves are obtained from a nonlinear analysis, considering the capacity spectra. Expected seismic damage is gotten with the damage probability matrices, which indicate the occurrence probability of a damage state for a seismic demand given. The analysis of the buildings has been performed by TreMuri program by means of a macroelements model, which represents of a whole masonry panel. The buildings, here, analyzed are real and detailed structural drawings and reports have been used to model them. The results shown a considerable vulnerability in this type of buildings, therefore, in spite of the seismic hazard the expected seismic risk is significant.Peer Reviewe