42 research outputs found

    El efecto de los depredadores en el comportamiento y en la respuesta fisiolóica de estrés en el conejo (Oryctolagus cuniculus)

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de lectura: 5-10-200

    Uso del storytelling para la introducción y aprendizaje de la lengua inglesa en el aula.

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    En este trabajo se ofrecerá una visión del storytelling como técnica para el aprendizaje de la lengua inglesa. Aunque esta técnica cuenta con múltiples definiciones, nos ceñiremos aquí al concepto dentro del ámbito educativo. Esta técnica puede implementarse en cualquier área del currículo al trabajar todo tipo de contenidos, cobrando especial importancia en la adquisición y el aprendizaje de una segunda lengua, ya que los cuentos ayudan a desarrollar las cuatro destrezas básicas de la lengua: hablar, escribir, leer y escuchar. Además, la técnica tiene un alto contenido de motivación para el estudiante, lo que garantiza el éxito del aprendizaje. No obstante es necesario que el docente domine ciertas habilidades que se expondrán en este Trabajo Fin de Grado

    EURECA: European-Japanese microcalorimeter array

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    The EURECA project aims to demonstrate technological readiness of a micro-calorimeter array for application in future X-ray astronomy missions, like Constellation-X, EDGE, and XEUS. The prototype instrument consists of a 5 × 5 pixel array of TES-based micro-calorimeters read out by two SQUID-amplifier channels using frequency-domain-multiplexing (FDM) with digital base-band feedback. The detector array is cooled by a cryogen-free cryostat consisting of a pulse tube cooler and a two stage ADR. Initial tests of the system at the PTB beam line of the BESSY synchrotron showed stable performance and an X-ray energy resolution of 1.5 eV at 250 eV for read-out of one TES-pixel only. Next step is deployment of FDM to read-out the full array. Full performance demonstration is expected end 2008.This work was financially supported by the Dutch Organization for Scientific Research (NWO).Peer Reviewe

    Ambient temperature affects postnatal litter size reduction in golden hamsters

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    International audienceBackground: To better understand how different ambient temperatures during lactation affect survival of young, we studied patterns of losses of pups in golden hamsters (Mesocricetus auratus) at different ambient temperatures in the laboratory, mimicking temperature conditions in natural habitats. Golden hamsters produce large litters of more than 10 young but are also known to wean fewer pups at the end of lactation than they give birth to. We wanted to know whether temperature affects litter size reductions and whether the underlying causes of pup loss were related to maternal food (gross energy) intake and reproductive performance, such as litter growth. For that, we exposed lactating females to three different ambient temperatures and investigated associations with losses of offspring between birth and weaning. Results: Overall, around one third of pups per litter disappeared, obviously consumed by the mother. Such litter size reductions were greatest at 30°C, in particular during the intermediate postnatal period around peak lactation. Furthermore, litter size reductions were generally higher in larger litters. Maternal gross energy intake was highest at 5°C suggesting that mothers were not limited by milk production and might have been able to raise a higher number of pups until weaning. This was further supported by the fact that the daily increases in litter mass as well as in the individual pup body masses, a proxy of mother's lactational performance, were lower at higher ambient temperatures. Conclusions: We suggest that ambient temperatures around the thermoneutral zone and beyond are preventing golden hamster females from producing milk at sufficient rates. Around two thirds of the pups per litter disappeared at high temperature conditions, and their early growth rates were significantly lower than at lower ambient temperatures. It is possible that these losses are due to an intrinsic physiological limitation (imposed by heat dissipation) compromising maternal energy intake and milk production

    Le lapereau en développement : données comportementales, alimentaires et sensorielles sur la période naissance-sevrage

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    Synthèse du chapitre écrit par les auteurs pour le Congrès Mondial de Cuniculture (Coureaud et al 2008b)National audienceBlind and deaf at birth, rabbit newborns need, as all mammal newborns, to rapidly interact with the mother to find the nipples and suck. This usually occurs only once per day, during an interaction drastically limited in time, both in domestic and natural conditions. After days 10-15, the mother-young interactions change progressively, leading to weaning between 4 and 6 weeks. In this context of rapid development of the young, lactating rabbit females and pups have developed some sensory, physiological and behavioural adaptations allowing them to communicate, and allowing the young to ingest milk then solid food efficiently. Here, we present some of these adaptations, taking examples from experimental studies run by several groups during the last decades. This paper is a summary of a chapter and communication recently presented during the last World Rabbit Congress (Coureaud et al 2008b).Aveugles et sourds à la naissance, les lapins nouveau-nés doivent, comme tous les mammifères nouveau-nés, interagir rapidement avec la mère afin de trouver rapidement une tétine et téter. Cela se produit généralement une seule fois par jour, au cours d’une très brève interaction, en conditions d’élevage comme en milieu naturel. Après les 10-15 j qui suivent la naissance, la relation mère-jeunes évolue progressivement, et conduit habituellement au sevrage entre 4 et 6 semaines. Dans ce contexte de développement rapide des jeunes, les femelles allaitantes et les lapereaux ont développé des adaptations sensorielles, physiologiques et comportementales leur permettant de communiquer, et permettant aux jeunes d’ingérer efficacement le lait puis les aliments solides. Ici, nous présentons quelques-unes de ces adaptations, en prenant des exemples d’études expérimentales conduites par différents groupes au cours des dernières décennies. Cet article est une synthèse du chapitre écrit par les auteurs pour le Congrès Mondial de Cuniculture (Coureaud et al 2008b)

    Testing the threat-sensitive predator avoidance hypothesis: physiological responses and predator pressure in wild rabbits

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    Predation is a strong selective force with both direct and indirect effects on an animal’s fitness. In order to increase the chances of survival, animals have developed different antipredator strategies. However, these strategies have associated costs, so animals should assess their actual risk of predation and shape their antipredator effort accordingly. Under a stressful situation, such as the pres- ence of predators, animals display a physiological stress response that might be proportional to the risk perceived. We tested this hypothesis in wild European rabbits (Oryctolagus cuniculus), subjected to different predator pressures, in Don˜ ana National Park (Spain). We measured the concentrations of fecal corticosterone metabolites (FCM) in 20 rabbit populations. By means of track cen- suses we obtained indexes of mammalian predator presence for each rabbit population. Other factors that could modify the physiological stress response, such as breeding status, food availability and rabbit density, were also considered. Model selection based on information theory showed that predator pressure was the main factor triggering the glucocorticoid release and that the physio- logical stress response was positively correlated with the indexes of the presence of mammalian carnivore predators. Other factors, such as food availability and density of rabbits, were considerably less important. We conclude that rabbits are able to assess their actual risk of predation and show a threat-sensitive physiological responsePeer reviewe

    Sexual differences in phenotypical predictors of floating status: body condition influences male but not female reproductive status in a wild passerine

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    Floaters constitute the sexually mature but non-breeding part of populations. Despite being ubiquitous in most species, knowledge about floaters is scarce. Ignoring this significant number of individuals may strongly bias our understanding of population dynamics and sexual selection processes. We used the spotless starling (Sturnus unicolor) to examine whether phenotypical and non-phenotypical variables from early and adult life predict reproductive status, focusing on the earliest age at which most individuals start to breed, when the percentage of floaters is the highest. We compiled data from a long-term study involving eight female and seven male cohorts of individuals PIT-tagged at birth. We compared a suite of nestling (condition, hatching date and brood size) and adult variables (condition, size and ornamentation) between floaters and breeders. We found that adult and nestling body condition strongly and positively influenced the likelihood of breeding in males. Path analysis revealed that male reproductive status could only be predicted by considering nestling body condition—the influence of this variable superseded adult body condition. Female reproductive status was only negatively associated with hatching date. Ornamentation was not associated with reproductive status in any of the sexes, although path analyses revealed that body condition was positively associated with throat feather length. We conclude that predictors of reproductive status are sex-specific in the spotless starling, suggesting an important role of body condition in access to breeding resources in males. Our results also highlight the long-term influence of early life on life trajectories and their potential implications on floating status.This work was financed by a grant from the Spanish Ministry of Science and Universities to DG (CGL2017-83843-C2-1-P), and draws on data collected during previous projects of DG (refs.: CGL2008-03501/BOS, CGL2011-26318 and CGL2017-83843-C2-1-P) and LP-R (ref.: PGC2018-099596-B-I00 funded by MCIN/AEI/10.13039/501100011033 and ERDF A way of making Europe).Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Peer reviewe

    Sexual differences in phenotypical predictors of floating status in a secondary cavity nester

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    Trabajo presentado al ASAB Summer Meeting, celebrado en Belfast (K) del 23 al 25 de agosto de 2021.Peer reviewe
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