154 research outputs found

    Effects of experimental tail shortening on the phenotypic condition of barn swallows Hirundo rustica: Implications for tail-length evolution

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    Some studies have suggested that tail streamers in the barn swallow Hirundo rustica may have been elongated 10-12 mm by sexual selection, but according to other studies, the length of these feathers is at the aerodynamic optimum or very close to it. To shed light on this issue, outermost tail feathers were experimentally shortened in male and female barn swallows by 1, 11 or 21 mm. Changes in four physiological parameters commonly used to estimate phenotypic condition in birds (weight, erythrocyte sedimentation rate, blood leukocyte concentration and heterophil/lymphocyte ratio) were checked one month later. Health improved (blood leukocyte concentration decreased) in the group of birds with tails shortened by 11 mm (both males and females), but body condition deteriorated (weight decreased) compared to the other two experimental groups. There was no significant effect of tail-length manipulation on the other two physiological parameters. These contradictory results suggest trade-offs between components of phenotypic condition. Possible negative relationships between condition-related traits imply that using one or very few physiological parameters to estimate phenotypic condition might not be appropriate. The most plausible explanation for the turning point in phenotypic condition when streamers were shortened by 11 mm is that these feathers are 7-15 mm longer than the aerodynamic optimum in both sexes. Therefore, our results are consistent with the hypothesis that tail streamers have been elongated 10-12 mm by sexual selection. This conclusion disagrees with a previous study on the effect of experimental tail shortening on haematocrit, but the complexity of interpreting changes in haematocrit might account for this discrepancy. © 2014 The Authors.The study was funded by the Andalusian Regional Government (Acc. Coord. 2001) and by the Spanish Ministry of Science and Technology and the European Regional Development Fund (projects BOS2001-1717 and CGL2008-00137/BOS).Peer Reviewe

    Whole Core Pin-by-Pin Coupled Neutronic-Thermal-hydraulic Steady state and Transient Calculations using COBAYA3 code

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    Nowadays, coupled 3D neutron-kinetics and thermal-hydraulic core calculations are performed by applying a radial average channel approach using a meshing of one quarter of assembly in the best case. This approach does not take into account the subchannels effects due to the averaging of the physical fields and the loose of heterogeneity in the thermal-hydraulic modelization. Therefore the models do not have enough resolution to predict those subchannels effects which are important for the fuel design safety margins, because it is in the local scale, where we can search the hottest pellet or the maximum heat flux. The UPM advanced multi-scale neutron-kinetics and thermal-hydraulics methodologies being implemented in COBAYA3 include domain decomposition by alternate core dissections for the local 3D fine-mesh scale problems (pin cells/subchannels) and an analytical nodal diffusion solver for the coarse mesh scale coupled with the thermal-hydraulic using a modelization of one channel per assembly or per quarter of assembly. In this work, we address the domain decomposition by the alternate core dissections methodology applied to solve coupled 3D neutronic/thermal-hydraulic (N-TH) problems at the fine-mesh scale. The N-TH coupling at the cell-subchannel scale allows the treatment of the effects of the detailed TH feedbacks on cross-sections, thus resulting in better estimates of the local safety margins at the pin level

    Biología reproductiva de la avoceta ("Recurvirostra avosetta") y la cigüeñela ("Himantopus himantopus") en el sur de España

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    Tesis Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Biología Animal I (Zoología), leída el 28-06-1993Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

    Sexually Selected Egg Coloration in Spotless Starlings

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    It has been recently proposed that the blue-green coloration in eggs of many avian species may constitute a sexually selected female signal. Blue-green color intensity would reflect the physiological condition of females, and hence it might also affect the allocation of male parental care. In this study, we use three different experimental approaches to explore the importance of sexual selection on blue-green egg coloration of spotless starling (Sturnus unicolor) eggs. First, experimental deterioration of female body condition (by means of wing feather removal) negatively affected the intensity of blue-green egg coloration. Second, blue-green color intensity of artificial model eggs had a significant positive influence on paternal feeding effort. Finally, we found a negative relationship between the effect of experimental food supply on nestling immunocompetence and the intensity of blue-green coloration of eggs, suggesting that egg color predicts nutritional conditions that nestlings will experience during development. All these results taken together strongly support a role of sexual selection in the blue-green coloration of spotless starling eggs.This research was funded by the Spanish Ministry of Education and Science and the Fondo Europeo de Desarrollo Regional (FEDER; CGL2004-01777/BOS).Peer reviewe

    Structure de la végétation en hêtraies-sapinières : effets sur le peuplement d’oiseaux

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    Vegetation structure and composition, and parameters of the bird community (richness and abundance) were studied in managed beech-fir forests in Navarre (Spain). Relationships between bird parameters and vegetation variables differed in different avian nesting guilds. Whereas secondary cavitynesting bird parameters were not significantly related to any vegetation variable, both richness and abundance of bird species that do not rely on existing holes for breeding increased with the proportion of fir trees, but only in the breeding season. Nest-site selection might be the key factor behind this relationship, since firs would provide more suitable nest-sites than beeches for these species, perhaps because beech leaves are not fully developed early in the breeding season. Moreover, during the winter season richness of birds that do not rely on existing holes for breeding was positively related to the percentage of shrub cover. Although this result should be considered with caution, protection from adverse weather conditions or predation might explain this relationshipEntre mai 2001 et mars 2002, la structure et la composition de la végétation, ainsi que les paramètres de la communauté d'oiseaux (richesse et abondance) dans les forêts mixtes entretenues de hêtres et de sapins (Fagus sylvatica - Abies alba) de Navarre (nord de l'Espagne) ont fait l'objet d'une étude. Les relations entre les paramètres des oiseaux et les variables de la végétation différaient entre divers groupes d'oiseaux en fonction de leurs habitudes de nidification. Les paramètres des oiseaux utilisant les trous d'arbre pour nicher n'ont montré aucune relation avec les variables de la végétation ; en revanche l'abondance tout comme la richesse des espèces ne dépendant pas des trous d'arbre pour se reproduire affichaient une relation positive avec la proportion de sapins, mais uniquement en période de reproduction. Cette relation pourrait s'expliquer par la sélection du lieu de nidification, les sapins offrant des lieux plus appropriés à la nidification que les hêtres pour ce groupe d'oiseaux, peut-être parce que les feuilles des hêtres ne sont pas entièrement développées au début de la saison de reproduction. En outre, en hiver la richesse des espèces ne dépendant pas des trous d'arbre pour nicher était en relation positive avec la proportion d'arbustes. Bien que ce résultat doive être interprété avec prudence, la protection vis-à-vis des conditions météorologiques défavorables ou les prédateurs pourrait expliquer cette relation

    Deportividad Económica

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    Se considera que el mundo del deporte es un mercado muy utilizable para explicar tanto de forma teórica como práctica conocimientos como la Economía o el emprendimiento debido a que su comprensión es más sencilla que otros mercados que su uso es más complejo, y además por su universalidad, todos los alumnos pueden conocer los casos que se trabajan en el aula

    Interface discontinuity factors in the modal eigenspace of the multigroup diffusion matrix

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    Interface discontinuity factors based on the Generalized Equivalence Theory are commonly used in nodal homogenized diffusion calculations so that diffusion average values approximate heterogeneous higher order solutions. In this paper, an additional form of interface correction factors is presented in the frame of the Analytic Coarse Mesh Finite Difference Method (ACMFD), based on a correction of the modal fluxes instead of the physical fluxes. In the ACMFD formulation, implemented in COBAYA3 code, the coupled multigroup diffusion equations inside a homogenized region are reduced to a set of uncoupled modal equations through diagonalization of the multigroup diffusion matrix. Then, physical fluxes are transformed into modal fluxes in the eigenspace of the diffusion matrix. It is possible to introduce interface flux discontinuity jumps as the difference of heterogeneous and homogeneous modal fluxes instead of introducing interface discontinuity factors as the ratio of heterogeneous and homogeneous physical fluxes. The formulation in the modal space has been implemented in COBAYA3 code and assessed by comparison with solutions using classical interface discontinuity factors in the physical spac

    Effects of cross sections tables generation and optimization on rod ejection transient analyses

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    Best estimate analysis of rod ejection transients requires 3D kinetics core simulators. If they use cross sections libraries compiled in multidimensional tables,interpolation errors – originated when the core simulator computes the cross sections from the table values – are a source of uncertainty in k-effective calculations that should be accounted for. Those errors depend on the grid covering the domain of state variables and can be easily reduced, in contrast with other sources of uncertainties such as the ones due to nuclear data, by choosing an optimized grid distribution. The present paper assesses the impact of the grid structure on a PWR rod ejection transient analysis using the coupled neutron-kinetics/thermal-hydraulicsCOBAYA3/COBRA-TF system. Forthispurpose, the OECD/NEA PWR MOX/UO2 core transient benchmark has been chosen, as material compositions and geometries are available, allowing the use of lattice codes to generate libraries with different grid structures. Since a complete nodal cross-section library is also provided as part of the benchmark specifications, the effects of the library generation on transient behavior are also analyzed.Results showed large discrepancies when using the benchmark library and own-generated libraries when compared with benchmark participants’ solutions. The origin of the discrepancies was found to lie in the nodal cross sections provided in the benchmark

    The ATHAC Survey 04-05: observational study regarding the use of neuter dressings or dressings impregnated in an antibacterian agent using an innovative patented technology: the lipid colloid technology for the treatment of acute and/or chronic wounds

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    Introducción: El estudio ATHAC recoge datos sobre heridas agudas y crónicas que son candidatas a un tratamiento a base de apósitos grasos neutros como la gama URGOTUL. Objetivos: Describir las características de las heridas, describir los tratamiento aplicados a estas heridas y explorar las opiniones de los profesionales de enfermería y los pacientes sobre los tratamientos en términos de aplicabilidad, adaptabilidad y confort para el paciente. Material y métodos: 1.500 pacientes fueron incluidos en el estudio de acuerdo al tipo de herida y a los tratamientos en uso. Se recogieron datos a partir de dos cuestionarios: uno para el paciente y otro para la enfermera responsable de sus cuidados. Las enfermeras recogieron los datos en el primer día de inclusión y los pacientes respondían al cuestionario 1 mes más tarde o antes si la herida había cicatrizado. Las variables recogidas por la enfermera fueron: datos sociodemográficos, etiología de las lesiones, características y localización de las heridas, aspectos y opiniones sobre el tratamiento. A los pacientes se les preguntó por la duración del tratamiento, el estado de la lesión en el momento de contestar y desde su punto de vista, así como su opinión sobre el dolor, satisfacción general y aceptabilidad. Se llevaron a cabo análisis descriptivos uni y bivariados. Para cada paciente, si tenía más de una lesión, se recogieron datos de la lesión de mayor tamaño. Resultados: Finalmente, se estudiaron 1.432 pacientes con una o más lesiones (420 tenían más de una lesión). El 60,4% eran mujeres y la edad media fue de 66 ± 19 años. En el caso de las heridas crónicas (657 lesiones) predominaron las úlceras venosas (47%) y las úlceras por presión (23%). En las heridas agudas (775 lesiones), la mayoría fueron traumáticas (41%) y quemaduras (32,5%). La principal localización en todas las lesiones fueron los miembros inferiores (57,4% en heridas crónicas y 39% en agudas). El 84,4% de los casos indicó presentar algún tipo de dolor previo al comienzo de este estudio. Al finalizar el estudio, un porcentaje menor del 20% indicó presentar algún tipo de dolor. El 72% de las heridas agudas y el 35% de las crónicas, como refieren los pacientes, había cicatrizado al finalizar el estudio (en un tiempo medio de entre 20-40 días). El 54% de las heridas crónicas evoluciona favorablemente y el 26% de las agudas. Más del 80% de las heridas estudiadas fueron tratadas con la gama URGOTUL. Conclusión: URGOTUL es una buena opción para el tratamiento de este tipo de heridas, especialmente para las heridas agudas, en relación a su carácter atraumático y a su capacidad de cicatrización, así como la buena aceptación y satisfacción de los pacientes.Introduction: The ATHAC survey collected data on acute or chronic wounds that were candidates for a treatment with grassy dressings like URGOTUL. Aims: To describe the wound’s characteristics, to describe treatments applied to these wounds and to Explore Nurses’ and patients’ opinion about the treatments in terms of applicability, adaptability and patient comfort. Methods: 1,500 patients were included in the study according to wound types and treatments. Data were collected with nurses and patient questionnaires. Nurses collected data the first day of inclusion and patients respond one month after or when wounds healed. Variables collected by nurses were: demographic, aetiology, characteristics and location of the wound, aspects and opinions of the treatment. Patients were asked about duration of treatments, wound state from their point of view and opinions about pain, satisfaction and acceptability. Univariate and bivariate descriptive analysis were conducted. For each patient was selected the biggest wound for data collection. Results: Finally, 1432 patients with one or more lesions were studied (420 had more than one). 60,4% were women and the mean age was 66. Chronic wounds, mainly, were venous leg ulcer (47%) and pressure ulcers (23%). In acute wounds, were traumatic (41%) and burns (32,5%). The main location was inferior extremities (57,4% in chronic and 39% in acute). 49% of cases reported moderate to high spontaneous pain previous to this study. At the end, only 20-30% reported pain (during the study, in more than 80% the dressing used was Urgotul). 72% of acute wounds and 35% of chronic wounds, as referred by patients, were healed when finished the study (between 20-40 days of treatment). Conclusion: Urgotul is a good option for atraumatic treatment of this type of lesions, mainly for acute wounds, since more of them had healed in an acceptable time with a good patient satisfaction

    Mercury Levels in Feathers of Penguins from the Antarctic Peninsula Area: Geographical and Inter-Specific Differences

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    Polar regions, symbols of wilderness, have been identified as potential sinks of mercury coming from natural and anthropogenic sources at lower latitudes. Changes in ice coverage currently occurring in some areas such as the Antarctic Peninsula could enhance these phenomena and their impacts on local biota. As long-lived species at the top of food chains, seabirds are particularly sensitive to this highly toxic metal with the capacity to be biomagnified. Specifically, their feathers can be useful for Hg monitoring since they mainly accumulate its most toxic and persistent form, methyl-Hg. To that end, feathers of gentoo (Pygoscelis papua), chinstrap (P. antarcticus), and Adélie penguins (P. adeliae) (n = 108) were collected by passive sampling in seven different locations throughout the Antarctic Peninsula area and analyzed by ICP-MS after microwave-digestion. More than 93% of the samples showed detectable Hg levels (range: 6.3-12,529.8 ng g-1 dry weight), and the highest ones were found in the feathers of chinstrap penguins from King George Island. Hg bioconcentration and biomagnification seem to be occurring in the Antarctic food web, giving rise to high but non-toxic Hg levels in penguins, similar to those previously found in Arctic seabirds.This research has been funded by the Spanish Ministry of Science and Innovation CGL2004-01348, POL2006-05175, and CGL2007-60369.S
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