331 research outputs found

    Costs of migratory decisions: A comparison across eight white stork populations

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    Flack, Andrea et al.Annual migratory movements can range from a few tens to thousands of kilometers, creating unique energetic requirements for each specific species and journey. Even within the same species, migration costs can vary largely because of flexible, opportunistic life history strategies. We uncover the large extent of variation in the lifetime migratory decisions of young white storks originating from eight populations. Not only did juvenile storks differ in their geographically distinct wintering locations, their diverse migration patterns also affected the amount of energy individuals invested for locomotion during the first months of their life. Overwintering in areas with higher human population reduced the stork’s overall energy expenditure because of shorter daily foraging trips, closer wintering grounds, or a complete suppression of migration. Because migrants can change ecological processes in several distinct communities simultaneously, understanding their life history decisions helps not only to protect migratory species but also to conserve stable ecosystems.A.F. was supported by the German Aerospace Center (DLR); J.B. was supported by projects i-link0564, CGL2012-32544, and 511/2012 from the Spanish Consejo Superior de Investigaciones Científicas, National Parks, National Ministries, and FEDER (European Regional Development Fund) funds. We acknowledge the support of Deutsch-Israelische Projektkooperation grants (Deutsche Forschungsgemeinschaft) NA 846/1-1 and WI 3576/1-1.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

    Non-linear dynamic analysis of the response of moored floating structures

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    © 2016 Elsevier Ltd. The complexity of the dynamic response of offshore marine structures requires advanced simulations tools for the accurate assessment of the seakeeping behaviour of these devices. The aim of this work is to present a new time-domain model for solving the dynamics of moored floating marine devices, specifically offshore wind turbines, subjected to non-linear environmental loads. The paper first introduces the formulation of the second-order wave radiation-diffraction solver, designed for calculating the wave-floater interaction. Then, the solver of the mooring dynamics, based on a non-linear Finite Element Method (FEM) approach, is presented. Next, the procedure developed for coupling the floater dynamics model with the mooring model is described. Some validation examples of the developed models, and comparisons among different mooring approaches, are presented. Finally, a study of the OC3 floating wind turbine concept is performed to analyze the influence of the mooring model in the dynamics of the platform and the tension in the mooring lines. The work comes to the conclusion that the coupling of a dynamic mooring model along with a second-order wave radiation-diffraction solver can offer realistic predictions of the floating wind turbine performance.Postprint (published version

    Personal reflections on Gary Bortolotti's links with Spain

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    Letter.Peer reviewe

    Feather growth bands and photoperiod

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    Growth bands are alternate dark/light bands perpendicular to the feather rachis. Previous studies indicate that pairs of dark/light bands are grown every 24 h, with light bands being produced at night, and dark ones during the day. Thus, the dark:light width ratio could reflect the photoperiod under which a feather was grown. We tested this hypothesis by inducing feathers to grow under contrasting photoperiods, using red-legged partridges Alectoris rufa as a model species. We first validated the assumption that a pair of dark/light band is produced every day. Secondly, we show that dark/light width ratios remain close to 1:1, irrespective of the photoperiod under which feathers were grown. Dark:light width ratios of feathers grown in summer (15 light-hours: 9 darkness-hours) and winter solstices (9l:15d) did not show any consistent pattern of variation within individuals. Thus, the dark/light banding patterns are not simply the product of light regimes and are not indicative of photoperiod. This finding, together with reports of ‘‘aberrant’’ growth band patterns (e.g. two growth bands produced over 24 h instead of one) challenges our current knowledge of growth bands. We propose that the normal circadian periodicity of growth bands is primarily driven by circadian rhythms: band formation starts at a point of critically low physiological activity (e.g. during night resting), and thus every 24 h irrespective of photoperiod. Our experiment emphasises that our knowledge of growth bands is weaker than previously appreciated, and that the study of dark/light band patterns on feathers could shed new light on interesting phenomena such as unusual avian biological rhythms and the functioning of internal clocks. Detecting ‘‘aberrant’’ banding patterns could therefore allow identifying bird species with unusual activity patterns or physiological rhythms.RJ, JB and CN were founded with a postdoctoral fellowship from the Ministerio de Ciencia e Innovacion (Spain), a postdoctoral I3P contract (CSIC/European Union) and a predoctoral grant from the Spain’s Ministry of Science and Technology (BES-2005-8619) respectively.Peer reviewe

    Influencia de la reducción de los gastos no deducibles en la liquidez de la Empresa Constructora Fertecnica (Perú) S.A, Lima – 2015

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    El presente trabajo de investigación tiene como objeto dar a conocer: la influencia de la reducción de los gastos no deducibles en la liquidez de las empresas, a través de un análisis tributario de lo dictaminado en la Ley del Impuesto a la Renta y su implicancia en la empresa “FERTECNICA (PERÚ) SA”, el cual ayudará favorablemente en la gestión económica – tributaria y el cumplimiento de los objetivos de la misma La investigación tuvo como objetivo general: Determinar de qué manera la reducción de los Gastos no Deducibles influirá en la liquidez de la empresa constructora: “FERTECNICA (PERÚ) SA”, Lima - 2015. Para lograr este objetivo se realizó una revisión de todos los datos contables utilizados en el área de contabilidad durante el periodo enero – abril 2015 relacionado con los gastos no deducibles, con la finalidad de ser analizados e interpretados. De acuerdo al trabajo que se ha realizado a la empresa “FERTECNICA (PERÚ) SA” y basándose en la aplicación de una entrevista a través de un cuestionario al contador y los asistentes, se ha determinado que la empresa tendrá pagos excesivos generados por los gastos no deducibles, por lo que en el presente trabajo de investigación se propone reducir la incidencia de los gastos no deducibles en la empresa, elaborando una propuesta en el ANEXO N°01 cuya finalidad es reducir los pagos generados por los gastos no deducibles y no afectar la liquidez que tiene la empresa. Como conclusión de esta investigación se puede decir que si la empresa aplica lo sugerido en nuestra propuesta, la organización reducirá sus gastos no deducibles, y como consecuencia su liquidez no se verá afectada por los pagos generados por los gastos no deducibles.This research aims to present: the influence of the reduction in non-deductible business expenses liquidity, through a tax analysis of what was ruled in the Law of Income Tax and its implication in the company "FERTECNICA (PERU) SA", which will help favorably in economic management - Tax and compliance with the objectives of the same The study had as general objective: To determine how the reduction of non-deductible expenses affects the liquidity of the construction company "FERTECNICA (PERU) SA" Lima - 2015. To achieve this objective, a review of all accounting data used in the area of accounting for the period January-April 2015 related to non-deductible expenses was conducted, in order to be analyzed and interpreted. According to the work that has been done to the company "FERTECNICA (PERU) SA", and based on the application of an interview through a questionnaire to the Accountant chief and assistants, it has been determined that the company will have overpayments generated by the nondeductible expenses , thus this research aims to reduce the incidence of non-deductible expenses in the company, in addition elaborating a proposal in the Annex No. 01 aimed to reduce the payments arising from non-deductible expenses and not to affect the liquidity that the company has. In conclusion of this research we can say that if the company apply the propposal that has been suggested, the organization will reduce its non-deductible expenses, and consequently its liquidity will not be affected by the payments arising from nondeductible expenses.Tesi

    Personalidad eficaz y motivación académica en los estudiantes universitarios de Historia y Geografía de la Universidad Nacional Enrique Guzmán y Valle

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    La presente investigación tiene como objetivo central establecer si las variables personalidad eficaz y motivación académica se encuentran relacionadas entre sí. La muestra del presente estudio se aplicó con los estudiantes de Historia y Geografía de la Facultad de Ciencias Sociales y Humanidades de la Universidad Nacional de Educación. Se utilizó el diseño descriptivo correlacional. Donde se aplicó dos instrumentos de evaluación: El inventario de personalidad eficaz de Martín del Buey y un cuestionario de motivación académica a 158 estudiantes. Estos instrumentos fueron sometidos a los análisis respectivos que determinaron que las pruebas son válidas y confiables. Los resultados indican que existen correlaciones significativas entre la personalidad eficaz y la motivación académica en los estudiantes de la muestra. Así mismo se pueden observar la existencia de correlaciones entre cada una de las dimensiones de personalidad eficaz y de motivación académica.The objective of this research is to establish whether the variables effective personality and academic motivation are related to each other. The sample of the present study was applied with the students of History and Geography of the Faculty of Social Sciences and Humanities of the National University of Education. The descriptive correlational design was used. Where two assessment instruments were applied: The Martín del Buey effective personality inventory and an academic motivation questionnaire to 158 students. These instruments were subjected to the respective analyzes that determined that the tests are valid and reliable. The results indicate that there are significant correlations between effective personality and academic motivation in the students in the sample. Likewise, the existence of correlations between each of the dimensions of effective personality and academic motivation can be observed

    The importance of sustainable leadership among company directors in the audio-visual sector in Spain: a cultural, ethical, and legal perspective

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    Business sectors are generally evolving towards the adoption of models of sustainable practice, but is this also true in the specific audio-visual sector? This question leads us to examine whether sustainable practices are carried out in the image and sound sector, using sector business leadership as a starting point. Adopting a long-term perspective has helped companies survive difficult times, such as seemingly ever more frequent economic crises and recessions, as well as to overcome the current COVID-19 pandemic and its aftermath. Together with review of appropriate literature, the study aims to analyse the perception of managers in the audio-visual sector regarding styles of leadership in their organizations, through the Bee and Locust Sustainable Leadership framework that Avery and Bergsteiner developed in 2011. A quantitative study was carried out based on the analysis of the responses given by fifty middle and senior managers from the audio-visual sector in Spain who answered a 54-poit questionnaire. The findings yielded interesting results. Organizations within the audio-visual sector were found to display elements of both bee and locust leadership styles. The results showed that idea contribution and teamwork were valued by the managers interviewed. Furthermore, considerable importance was attached to the need to implement continuous training and the development of corresponding professional careers in companies. Overall, the results showed that there was a clear need for companies in the audio-visual sector to put greater effort into promoting and successfully achieving sustainable practices at the operational level.Los sectores empresariales están evolucionando hacia modelos de sostenibilidad, pero ¿lo es también para el sector audiovisual? Esta pregunta nos lleva a preguntarnos si en el sector de la imagen y el sonido se llevan a cabo prácticas sostenibles, tomando como punto de partida el liderazgo. Adoptar una perspectiva a largo plazo ha ayudado a las empresas a sobrevivir en tiempos difíciles, como crisis económicas y recesiones, así como en el contexto actual de pandemia de COVID-19. Junto con la revisión bibliográfica, el estudio pretende analizar la percepción de los directivos del sector audiovisual respecto al liderazgo en su organización, a través del marco de Liderazgo Sostenible de Abeja y Langosta que Avery y Bergsteiner desarrollaron en 2011. Se realizó un estudio cualitativo basado en la análisis de las respuestas de cincuenta mandos medios y altos del sector audiovisual en España que respondieron a un cuestionario de 54 preguntas. Los hallazgos arrojaron resultados interesantes. Se encontró que las organizaciones dentro del sector audiovisual muestran elementos de los estilos de liderazgo de ambos abejas y langostas. Los resultados mostraron que la aportación de ideas y el trabajo en equipo son valorados por los directivos entrevistados. Además, se dio mucha importancia a la necesidad de implementar la formación continua y el desarrollo de los profesionales en las empresas. En general, los resultados mostraron que existía una clara necesidad de que las empresas del sector audiovisual dedicaran un mayor esfuerzo para lograr prácticas sostenibles a nivel empresarial

    Modulation of the input–output function by GABAA receptor-mediated currents in rat oculomotor nucleus motoneurons

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    The neuronal input–output function depends on recruitment threshold and gain of the firing frequency–current (f–I) relationship. These two parameters are positively correlated in ocular motoneurons (MNs) recorded in alert preparation and inhibitory inputs could contribute to this correlation. Phasic inhibition mediated by γ-amino butyric acid (GABA) occurs when a high concentration of GABA at the synaptic cleft activates postsynaptic GABAA receptors, allowing neuronal information transfer. In some neuronal populations, low concentrations of GABA activate non-synaptic GABAA receptors and generate a tonic inhibition, which modulates cell excitability. This study determined how ambient GABA concentrations modulate the input–output relationship of rat oculomotor nucleus MNs. Superfusion of brain slices with GABA (100 μm) produced a GABAA receptor-mediated current that reduced the input resistance, increased the recruitment threshold and shifted the f–I relationship rightward without any change in gain. These modifications did not depend on MN size. In absence of exogenous GABA, gabazine (20 μm; antagonist of GABAA receptors) abolished spontaneous inhibitory postsynaptic currents and revealed a tonic current in MNs. Gabazine increased input resistance and decreased recruitment threshold mainly in larger MNs. The f–I relationship shifted to the left, without any change in gain. Gabazine effects were chiefly due to MN tonic inhibition because tonic current amplitude was five-fold greater than phasic. This study demonstrates a tonic inhibition in ocular MNs that modulates cell excitability depending on cell size. We suggest that GABAA tonic inhibition acting concurrently with glutamate receptors activation could reproduce the positive covariation between threshold and gain reported in alert preparation.España, Ministerio de Ciencia y Tecnología BFU 2009-0786

    Habitat selection by Black kite breeders and floaters: Implications for conservation management of raptor floaters

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    Preserving large predators is important but challenging because these species are typically wide-ranging, select multiple habitats at different scales and often present spatial or habitat separation between the breeder and floater sectors of a population. In addition, most of our knowledge on raptor floaters' habitat requirements comes from large solitary species, whose floaters often occupy temporary settlement areas spatially separate from breeding locations. Here, we examine space and habitat use by a loosely colonial, wetland-dependent raptor, the Black kite (Milvus migrans), in a population where floaters co-exist with territory holders, enabling a direct comparison of their habitat preferences. The study was conducted in Doñana National Park (South-Western Spain), a seasonally drying marshland currently surrounded by intensive agriculture and rice-fields. Intensive radio-tracking revealed that breeders and floaters selected and avoided the same habitats despite a radical, four-to-eight fold difference in their home-range dimensions: all kites over-selected open habitats suitable for their aerial foraging modes and avoided woodland and farmland. These results suggest a continuum of raptor population structures ranging from solitary species whose floaters select different habitats than breeders and are concentrated in spatially separate settlement areas, to colonial and semi-social species whose floaters fully coexist with breeders with shared habitat preferences. Both extremes of this continuum will pose challenges for conservation management. In solitary species, special conservation efforts may be required to identify and manage temporary settlement areas, while in gregarious species, the larger ranges of floaters may expose them to different threats than breeders, whose occurrence and consequences may be subtle to identify. © 2013 Elsevier Ltd.Peer Reviewe

    Tool development based on FAST for performing design optimization of offshore wind turbines: FASTLognoter

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    The new engineering FASTLognoter software is presented. This code is essentially the result of the integration of two tools, along with some additional features. Thefirst basis tool is FAST (developed by NREL), a comprehensive aeroelastic simulator code for wind turbines. The second basis tool is Lognoter (developed by CompassIS), a general-purpose commercial software for managing and creating engineering forms. The integration of FAST and Lognoter gives a useful, comprehensive and versatile toolkit, which is verified in this work by means of bibliographic documented cases. An important advantage of the tool presented is the parametric design capability, allowing the user of FAST/AeroDyn/HydroDyn codes to analyze a massive group of cases; therefore, optimal design can be carried out
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