Digestive enzymes in marine species. II. Amylase activities in gut from seabream (Sparus aurata), turbot (Scophthalmus maximus) and redfish (Sebastes mentella)

8 páginas, 3 tablas, 3 figurasThe amylase activity of the digestive tract of three carnivorous fish species (Spurus aurata, ScophtMmw maximus and Sebustes me&la) has been studied. The activity of seabream and turbot showed its maximum at neutral pH (7.0-7.5); meanwhile, the activity of redfish had an optimum pH at 4.5-5.0. The to function ranged between 35 and 45°C for the three species. The Arrhenius plots of the intestinal activities of seabream and turbot showed breakpoints at temperatures close to those of their physiological activities. High saline concentrations inhibited the activity of seabream and turbot and activated the activity of redfish. Seabream activity was absolutely dependent on calcium ions. On the contrary, redfish activity was only detected in the absence of this metal. Studies carried out by using several effecters suggested that the activities found in these three species are different. Considering our results from a point of view of the environmental conditions of these species, it might be concluded that enzymatic digestion of dietary carbohydrates proceeds at very low rate. Physiologicat implications are discussedThis work was supported b a grant from the Xunta de Galicia XUGA40201 B90.Peer reviewe

Modeling flow through non linear coarse porous media by a finite difference scheme, with application to rockfill dams overtopping

La circulación del agua a través de medios porosos gruesos, como la escollera, la grava o incluso la arena de mayor tamaño, tiene la particularidad de exhibir una relación no lineal entre el gradiente hidráulico y la velocidad de filtración. Uno de los problemas de ingeniería en que se observa esto es cuando se produce un sobrevertido en una presa de escollera y el agua, pasando sobre su coronación, se infiltra en el espaldón y circula por su interior. La modelación numérica del problema se resuelve aquí mediante un esquema de diferencias finitas, que se implementa en el código MNLEE.RDS para su aplicación al sobrevertido en presas de escollera. Además, se proporciona un procedimiento para resolver el acoplamiento del movimiento del agua en lámina libre sobre el talud de la presa y de filtración por el interior del espaldón, mediante la introducción del concepto «ley de intercambio de caudales».Flow through coarse porous media, as rockfill, gravel or sand of big size, exhibit a non linear relation between hydraulic gradient and seepage velocity. This behavior is observed when water flows over the crest of a rockfill dam, seeps into the downstream shoulder and moves through the rockfill voids. A finite difference scheme is used here to solve this problem through numerical modeling. It is implemented in the code MNLEE.RDS for solving dam overtopping problems. In addition, a procedure is provided to solve the coupled problem of flow over and through the rockfill dam. For that purpose, the concept of «law of flow exchange»is introduced.Peer Reviewe

Analysis of the discharge capacity of radial gated spillways using numerical modelling application to Oliana dam

Current paper focuses on the analysis of radial gated spillways, which are analyzed by the solution of a numerical model. The Oliana Dam study case is considered and the discharge capacity is predicted both by the application of a level-set based free-surface solver and by the use of traditional empirical formulations The results of the analysis are then used in training an Artificial Neural Network so to allow real-time predictions of the discharge in any situation of energy head and gate opening within the operation range of the reservoir. The comparison of the results obtained with the different methods shows that numerical models can be useful as a predictive tool for the analysis of the hydraulic performance of radial-gated spillways, and highlights some drawbacks regarding the application of the empirical formulas

Statistical Complexity and Nontrivial Collective Behavior in Electroencephalografic Signals

We calculate a measure of statistical complexity from the global dynamics of electroencephalographic (EEG) signals from healthy subjects and epileptic patients, and are able to stablish a criterion to characterize the collective behavior in both groups of individuals. It is found that the collective dynamics of EEG signals possess relative higher values of complexity for healthy subjects in comparison to that for epileptic patients. To interpret these results, we propose a model of a network of coupled chaotic maps where we calculate the complexity as a function of a parameter and relate this measure with the emergence of nontrivial collective behavior in the system. Our results show that the presence of nontrivial collective behavior is associated to high values of complexity; thus suggesting that similar dynamical collective process may take place in the human brain. Our findings also suggest that epilepsy is a degenerative illness related to the loss of complexity in the brain.Comment: 13 pages, 3 figure

Model for the analysis of the structural failure of the clay core in rockfill dams due to overtopping, A

Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.Includes bibliographical references.In 2014 the Dam Safety Research Group (SERPA) of the Technical University of Madrid performed several tests to assess the behavior of rockfill dams in overtopping scenarios. A structural failure pattern of the clay core was observed, as expected. Hence, it was concluded that a model to simulate the observed failure mechanisms was needed. The model described herein provides the first results on assessment of the clay core stability following failure of the downstream shell. The failure process may result in one or more brittle and abrupt breakage phases of the core, herein classified as structural breakages, as opposed to the progressive failure caused by the erosion of the cohesive material. Thus, total or partial failure of the clay core occurs when the acting forces reach one of the instability conditions: overturning or sliding. The model was utilized to retroactively analyze two experiments carried out in the laboratory; the results obtained were consistent with the experimental measurements. The model is based on simple mechanical principles, but represents a paradigm shift in the interpretation and evaluation of the overtopping failure processes, especially since it results in a failure hydrograph different from those typically adopted, and therefore, has repercussions in the development of emergency plans

Monte Carlo simulations of post-common-envelope white dwarf + main sequence binaries: comparison with the SDSS DR7 observed sample

Detached white dwarf + main sequence (WD+MS) systems represent the simplest population of post-common envelope binaries (PCEBs). Since the ensemble properties of this population carries important information about the characteristics of the common-envelope (CE) phase, it deserves close scrutiny. However, most population synthesis studies do not fully take into account the effects of the observational selection biases of the samples used to compare with the theoretical simulations. Here we present the results of a set of detailed Monte Carlo simulations of the population of WD+MS binaries in the Sloan Digital Sky Survey (SDSS) Data Release 7. We used up-to-date stellar evolutionary models, a complete treatment of the Roche lobe overflow episode, and a full implementation of the orbital evolution of the binary systems. Moreover, in our treatment we took into account the selection criteria and all the known observational biases. Our population synthesis study allowed us to make a meaningful comparison with the available observational data. In particular, we examined the CE efficiency, the possible contribution of internal energy, and the initial mass ratio distribution (IMRD) of the binary systems. We found that our simulations correctly reproduce the properties of the observed distribution of WD+MS PCEBs. In particular, we found that once the observational biases are carefully taken into account, the distribution of orbital periods and of masses of the WD and MS stars can be correctly reproduced for several choices of the free parameters and different IMRDs, although models in which a moderate fraction (<=10%) of the internal energy is used to eject the CE and in which a low value of CE efficiency is used (<=0.3) seem to fit better the observational data. We also found that systems with He-core WDs are over-represented in the observed sample, due to selection effects.Comment: 15 pages, 7 figures, accepted for publication in A&

Adaptación de los métodos de entrenamiento a las particularidades de la natación

The swimming has special circumstances when it comes to train and monitor physical activity. This has meant that over time have arisen research and resources that enable us to control the training process effectively with alternatives to the classic variables. In addition, the physiological behaviour in the aquatic environment varies from the exercise out of it, which also makes some methodological adaptations are necessary. Currently swimming is a growing sport for its great importance in the triathlon, and new technologies have also managed to offer new avenues for understanding and control of the training process and training. The correct handling of the variables that determine the training load is the key to the adaptations that bring us a better or help us counter the limiting factors of performance. This paper shows the main changes required volume programming, training intensity and density in the aquatic environment.La natación tiene unas circunstancias especiales a la hora de entrenar y monitorizar la actividad física que se lleva a cabo. Esto ha hecho que a lo largo del tiempo hayan surgido investigaciones y recursos que nos permitan controlar el proceso de entrenamiento de manera efectiva con alternativas a las variables clásicas. Además, el comportamiento fisiológico en el medio acuático varía respecto al ejercicio físico fuera de él, lo que también hace que sean necesarias algunas adaptaciones metodológicas. Actualmente la natación es un deporte creciente por su gran importancia dentro del triatlón, y las nuevas tecnologías también han logrado ofrecernos nuevas vías para el entendimiento y control del proceso formativo y de entrenamiento. El correcto manejo de las variables que determinan la carga de entrenamiento es la clave para conseguir las adaptaciones que nos aporten una mejora o nos ayude a contrarrestar los factores limitantes del rendimiento. Este trabajo muestra las principales modificaciones que requiere la programación del volumen, intensidad y densidad del entrenamiento en el medio acuático

Origem e diversidade clonal do lagarto partenogenético Aspidoscelis rodecki (Squamata: Teiidae): evidências cromossômicas.

Com a finalidade de investigar a origem e a diversidadecromossômica de Aspidoscelis rodecki, analisamos os cariótipos de indivíduos de duas populações diferentes desse lagarto unissexual. O cariótipo de A. rodecki possui um número diplóide de 50 cromossomos e exibe um heteromorfismo estrutural marcante. O arranjo cromossômico parece ter sido originado pela fissão de Todd após o surgimento da partenogênese (hibridização entre A. angusticeps e A. deppii). Esse padrão foi observado em duas populações da espécie, que é endêmica da Península de Yucatán.We analyzed the karyotypes of individuals of two different populations of Aspidoscelis rodecki to investigate the origin andchromosomal diversity of this unisexual lizard. The karyotype of A. rodecki has a diploid number of 50 chromosomes, and exhibits a marked structural heteromorphism. The unique arrangement seems to have originated by Todd´s fission after the origin of parthenogenesis (hybridization between A. angusticeps and A. deppii). This pattern was observed in two populations of the species, which is endemic to the Yucatan Peninsula.Con el fin de conocer el origen y la diversidad cromosómica deAspidoscelis rodecki, analizamos el cariotipo de individuos de dos poblaciones de esta lagartija unisexual. El cariotipo de A. rodecki presenta un número diploide de 50 cromosomas y muestra unmarcado heteromorfismo estructural. El arreglo cromosómico parece haberse originado a través de fisiones de Todd, posteriores al origen de la partenogénesis (hibridación entre A. angusticeps y A. deppii). Este patrón fue observado en dos poblaciones de la especie, que es endémica de la Península de Yucatán