49 resultados para Reproductive strategy


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[spa] En un modelo de Poisson compuesto, definimos una estrategia de reaseguro proporcional de umbral : se aplica un nivel de retención k1 siempre que las reservas sean inferiores a un determinado umbral b, y un nivel de retención k2 en caso contrario. Obtenemos la ecuación íntegro-diferencial para la función Gerber-Shiu, definida en Gerber-Shiu -1998- en este modelo, que nos permite obtener las expresiones de la probabilidad de ruina y de la transformada de Laplace del momento de ruina para distintas distribuciones de la cuantía individual de los siniestros. Finalmente presentamos algunos resultados numéricos.

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To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.

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The presence of Ursinia nana, an Anthemideae of South-African origin which has been introduced into the NE Iberian Peninsula, is reported for the fi rst time in Europe. The data offered cover its precise location, morphology, chromosome number, ecology and a population census, as well as its life cycle, fl oral structure, reproductive biology and fruit dispersal mechanisms. Of special note are the clear predominance of autogamy (geitonogamy) over xenogamy as a reproductive system and the large number of fruits produced with high and immediate germinative capacity. These characteristics permit rapid colonization by the introduced species, which can become invasive. However, fruit predation by the ant Messor barbarus points to a natural mechanism that helps regulate population growth and makes biological control possible. Finally its possibilities of expansion in the colonized area and of naturalization in the NE Iberian Peninsula are assessed.

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The aim of this work was to design a novel strategy to detect new targets for anticancer treatments. The rationale was to build Biological Association Networks from differentially expressed genes in drug-resistant cells to identify important nodes within the Networks. These nodes may represent putative targets to attack in cancer therapy, as a way to destabilize the gene network developed by the resistant cells to escape from the drug pressure. As a model we used cells resistant to methotrexate (MTX), an inhibitor of DHFR. Selected node-genes were analyzed at the transcriptional level and from a genotypic point of view. In colon cancer cells, DHFR, the AKR1 family, PKC¿, S100A4, DKK1, and CAV1 were overexpressed while E-cadherin was lost. In breast cancer cells, the UGT1A family was overexpressed, whereas EEF1A1 was overexpressed in pancreatic cells. Interference RNAs directed against these targets sensitized cells towards MTX.

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This study tests the hypothesis that female South American sea lions shift from off-shore, pelagic prey to coastal, benthic prey after parturition in order to reduce the foraging trip duration and hence the time pups remain unattended on the beach during early lactation. The δ13C and δ15N values of the serum and blood cells of 26 South American sea lion suckling pups from northern Patagonia were used to track the dietary changes of their mothers from late pregnancy to early lactation, after correction for differential isotopic fractionation between tissues. Primary producers and potential prey species were also analysed to establish a baseline for interpreting the stable isotope concentration of serum and blood cells. Isotopic ratios revealed a generalized increase in the consumption of coastal-benthic prey after parturition. Such a generalized post-partum shift will allow females to spend more time on land and look after their pups. The effects of this foraging strategy on the nutritional quality of the female"s diet are discussed.

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L'objectiu d'aquest projecte era desenvolupar una metodologia de user experience strategy per aconseguir que el client d'una pàgina web tingui una mateixa experiència tant si fa servir una plataforma com una altra, aplicant diferents tècniques de disseny centrades en l'usuari.

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Reproductive morphology of the Mediterranean red alga Kallymenia patens is described for the first time, confirming its position in the genus. K. patens is characterized by a non-procarpic female reproductive apparatus, carpogonial branch systems consisting of supporting cells bearing both three-celled carpogonial branches and subsidiary cells that lack a hypogynous cell and carpogonium; fusion cells develop numerous connecting filaments, and tetrasporangia are scattered over the thallus and are probably cruciately divided. Old fertile spathulate specimens of K. patens are morphologically similar to K. spathulata, but they can be distinguished by the length of spathulated proliferations (up to 0.6 cm and 6 cm, respectively), the length of inner cortical cells (up to 70 and 30 μm, respectively), and the gonimoblast location (in proliferations from the perennial part of the blade and over all the thallus surface, respectively)

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Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-­‐conceived twin pregnancies are at greater risk than non-­‐ART-­‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-­‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-­‐ conceived dichorionic twin pregnancies. In ART-­‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof

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Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-­‐conceived twin pregnancies are at greater risk than non-­‐ART-­‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-­‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-­‐ conceived dichorionic twin pregnancies. In ART-­‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof

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Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-­‐conceived twin pregnancies are at greater risk than non-­‐ART-­‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-­‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-­‐ conceived dichorionic twin pregnancies. In ART-­‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof

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This article presents preliminary research from an instructional design perspective on the design of the case method as an integral part of pedagogy and technology. Key features and benefitsusing this teaching and learning strategy in a Virtual Teaching and Learning Environment(VTLE) are identified, taking into account the requirements of the European Higher Education Area (EHEA) for a competence-based curricula design. The implications of these findings for alearning object approach exploring the possibilities of learning personalization, reusability and interoperability trough IMS LD, are also analyzed.

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We present a case study of the redesign of the organizational presentation and content of the Virtual Library website at the Universitat Oberta de Catalunya (Open University of Catalonia, UOC), based on a user-centered design strategy. The aim of the redesign was to provide users with more intuitive, usable and understandable content (textual content, resources and services) by implementing criteria of customization, transparency and proximity. The study also presents a selection of best practices for applying these criteria to the design of other library websites.

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We present a case study of the redesign of the organizational presentation and content of the Virtual Library website at the Universitat Oberta de Catalunya (Open University of Catalonia, UOC), based on a user-centered design strategy. The aim of the redesign was to provide users with more intuitive, usable and understandable content (textual content, resources and services) by implementing criteria of customization, transparency and proximity. The study also presents a selection of best practices for applying these criteria to the design of other library websites.

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We present a case study of the redesign of the organizational presentation and content of the Virtual Library website at the Universitat Oberta de Catalunya (Open University of Catalonia, UOC), based on a user-centered design strategy. The aim of the redesign was to provide users with more intuitive, usable and understandable content (textual content, resources and services) by implementing criteria of customization, transparency and proximity. The study also presents a selection of best practices for applying these criteria to the design of other library websites.

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The paper aim is to analyse the influence of the European Employment Strategy (EES)in the implementation of the Spanish labour market policies. The first part of the paper describes the evolution and content of the EES. In the second one, the definition of activation is also explained. In addition to that, the ways how the EES develops and promotes active labour market policies are examined. The evolution of labour market policies in Spain and the current configuration of both active and passive policies are studied in the next three chapters. In these parts, the paper investigates to which extent the provisions of the EES have been implemented in Spain. The paper shows that: i) activation has been rising in the European countries since the implementation of the EES; ii) this fact has also happened in relative terms (comparing the evolution of active to passive policies); iii) Spain has been one of the countries which has led these processes; iv) the EES seems to have been influencing