Dual regimes of ion migration in high repetition rate femtosecond laser inscribed waveguides

Ion migration in high repetition rate femtosecond laser inscribed waveguides is currently being reported in different optical glasses. For the first time we discuss and experimentally demonstrate the presence of two regimes of ion migration found in laser written waveguides. Regime-I, corresponds to the initial waveguide formation mainly via light element migration (in our case atomic weight < 31u), whereas regime-II majorly corresponds to the movement of heavy elements. This behavior brings attention to a problem which has never been analyzed before and that affects laser written active waveguides in which active ions migrate changing their local spectroscopic properties. The migration of active ions may in fact detune the pre-designed optimal values of active photonic devices. This paper experimentally evidences this problem and provides solutions to avert it.Comment: 4 pages, 5 figure

Valdeande, a dos leguas de camino de "Clunia". Novedades epigráficas

Abordamos el estudio de dos inscripciones ya conocidas, de las que damos nueva lectura e interpretación, y apuntamos su posible relación con Clunia. Asimismo, editamos otras tres piezas inéditas y tres grafitos hallados todos ellos en Valdeande (Burgos).In this paper, we present a new interpretation about the study of two known Latin inscriptions from Valdeande (Burgos), developing a new meaning of them and establishing a potential link with Clunia. In addition, we show three unpublished pieces and three graffities, all of them found in Valdeande (Burgos)

Contemplative sciences: A future beyond mindfulness

Mindfulness is a psychological technique based on Eastern meditative practices that was developed in the late 1970s by Kabat-Zinn at the University of Massachusetts. Initially, there was a debate over whether it should be considered a scientific technique or labelled as part of the new wave practices. Today, mindfulness is omnipresent in modern societies but has suffered from merchandising and banalization, which has been strongly criticized. Despite some limitations regarding methodological aspects of mindfulness research, it is considered effective for treating many physical and psychological disorders, and even it is recommended in clinical guidelines such the British National Institute for Health and Care Excellence. During the last 2500 years, mindfulness practices have moved from Northern India across most of Asia, but their mixing with Western science and culture at the end of the 20(th) century is considered a key event in recent history. For the first time in human history, due to globalization, the wisdom of all contemplative traditions can be shared with all human beings and assessed by science. Mindfulness practices, yoga included, are giving birth to a new field of knowledge, contemplative sciences, which go beyond mindfulness and is devoted to helping humanity to reach higher levels of happiness and mental peace

Connecting species’ geographical distributions to environmental variables: range maps versus observed points of occurrence

Connecting the geographical occurrence of a species with underlying environmental variables is fundamental for many analyses of life history evolution and for modeling species distributions for both basic and practical ends. However, raw distributional information comes principally in two forms: points of occurrence (specific geographical coordinates where a species has been observed), and expert-prepared range maps. Each form has potential short-comings: range maps tend to overestimate the true occurrence of a species, whereas occurrence points (because of their frequent non-random spatial distribution) tend to underestimate it. Whereas previous comparisons of the two forms have focused on how they may differ when estimating species richness, less attention has been paid to the extent to which the two forms actually differ in their representation of a species’ environmental associations. We assess such differences using the globally distributed avian order Galliformes (294 species). For each species we overlaid range maps obtained from IUCN and point-of-occurrence data obtained from GBIF on global maps of four climate variables and elevation. Over all species, the median difference in distribution centroids was 234 km, and median values of all five environmental variables were highly correlated, although there were a few species outliers for each variable. We also acquired species’ elevational distribution mid-points (mid-point between minimum and maximum elevational extent) from the literature; median elevations from point occurrences and ranges were consistently lower (median −420 m) than mid-points. We concluded that in most cases occurrence points were likely to produce better estimates of underlying environmental variables than range maps, although differences were often slight. We also concluded that elevational range mid-points were biased high, and that elevation distributions based on either points or range maps provided better estimates

Environmental factors influence both abundance and genetic diversity in a widespread bird species.

Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations

Algunos aspectos dinámicos en un modelo bioeconómico

Se estudian en este trabajo algunos aspectos relevantes de la teoría de Sistemas Dinámicos aplicados a un modelo de competición interespecies. Se trata de un estudio cualitativo en el cual, en función de los parámetros del sistema, se analizan los cambios en el número y/o estabilidad de los puntos de equilibrio del sistema. Todo ello con el objetivo de establecer los tipos de bifurcaciones que pueden presentarse en el modelo

Bifurcaciones de Hopf y ciclos límites en un modelo de control óptimo aplicado a la pesquería de chamelea gallina del litoral Suratlántico español

Este trabajo pretende ampliar el presentado en el IV Encuentro de Economía Aplicada (Reus, 2001) que, bajo el título Análisis de la estabilidad y de bifurcaciones en un modelo dinámico aplicado a la gestión de una pesquería, presentaba un modelo de control óptimo caracterizado por la tradicional presencia de un punto de silla y por la existencia de trayectorias cerradas de tipo ciclo límite para los valores de la tasa de descuento social que verificaran las hipótesis del teorema de bifurcación de Hopf. La aplicación de los resultados obtenidos a nivel teórico al caso de la pesquería de chamelea gallina de la región Suratlántica Española evidenció que tales trayectorias cerradas aparecían en un entorno de un equilibrio estacionario no factible en un caso real, pues el correspondiente nivel de biomasa era negativo. Dada la evolución histórica de la citada pesquería, se ha considerado la situación de la misma en la década de los años 60, a principios de la cual existían unos stocks de chirla apenas explotados, lo que nos ha llevado a formular el mismo problema de control empleando una tasa de capturas distinta de la habitual del modelo de Schaefer que habíamos usado en el primer trabajo. Mediante la aplicación del teorema de bifurcación de Hopf se establece así la presencia de ciclos límites en el sistema dinámico resultante de aplicar el principio del máximo de Pontryagin a este nuevo problema de contro

Análisis de la estabilidad y de bifurcaciones en un modelo dinámico aplicado a la gestión de una pesquería

Estudiamos en esta comunicación la estabilidad de las soluciones de equilibrio del sistema dinámico resultante de aplicar el Principio del Máximo de Pontryagin a un modelo de control óptimo para la gestión de una pesquería. Veremos cómo puede hablarse en un modelo de este tipo de la estabilidad condicional del punto de silla. Considerando la tasa de descuento social como parámetro del sistema, se analizan las bifurcaciones locales de codimensión uno, es decir, los cambios en la estabilidad de los equilibrios y/o la aparición de nuevos equilibrios u órbitas cerradas al considerar pequeñas variaciones de dicho parámetro. En este contexto, usamos el Teorema de Bifurcación de Hopf para establecer la existencia, bajo determinadas hipótesis, de trayectorias oscilatorias de tipo ciclo límit

Taxonomic clarification in W-Mediterranean Androcymbium (Colchicaceae): A. wyssianum sunk in the synonymy of A.gramineum and A.europaeum restored

Capsule dehiscence has been used as a diagnostic character for W Mediterranean species of Androcymbium. Depending on the state of capsule maturity, the character, however, can be ambiguous in herbarium material. Based on morphological, phenological and cpDNA characters it is shown that misinterpretation of the capsule as indehiscent in the type material of A. gramineum has led to serious taxonomic confusion. The combined analyses produced evidence that A. gramineum of the population from the type locality at Essaouira, Morocco, is conspecific with A. wyssianum. A. gramineum is therefore the correct name for the species with dehiscent capsules, whereas the populations with indehiscent capsules at the Atlantic coast north of Essaouira and in SE Spain represent a second species, which is correctly named A. europaeu