1,450 research outputs found
Benefits and costs of parental care
This chapter summarizes important advances in the understanding of the mechanisms underlying the costs and benefits of parental care. It starts by analysing the nature of parental resources, addressing also the possibility of cost-free resources. It then reviews short and long-term benefits of parental care and how parents adjust offspring phenotypes to attain such benefits. Similarly, it reviews physiological and non-physiological costs of parental care and the current support for a link with fitness. It concludes that, despite important recent advances, the integration of proximate mechanisms into ultimate explanations is still far from successful.Peer Reviewe
Covariation in oxidative stress markers in the blood of nestling and adult birds
Interest in the imbalance between the production of reactive oxygen species and the state of the antioxidant machinery—that is, oxidative stress—has recently grown among comparative physiologists and evolutionary/behavioral ecologists. The number and types of markers used to estimate oxidative stress is, however, under debate. The study of covariation among these markers is necessary to better interpret the information content of each independent variable. Here, the covariation in levels of 10 blood parameters in a group of zebra finches (Taeniopygia guttata) as nestlings and adults was analyzed across a large data set. Total glutathione levels in erythrocytes were negatively correlated with plasma carotenoid values in nestlings only, supporting the implication of carotenoids in the antioxidant machinery during a particularly stressful period of life. Plasma lipid levels (triglycerides [TRGs]) as well as plasma antioxidant capacity—the latter tested with and without control for uric acid levels—showed individual consistency with age. Plasma TRG and uric acid levels were strongly correlated with plasma lipid peroxidation and antioxidant capacity, respectively, suggesting an influence of recent intake or mobilization of energy stores on these variables. The meaning of oxidative stress markers, whether corrected or uncorrected for levels of nutritional metabolites, remains to be explored. Experiments manipulating diet composition and oxidative stress are necessary to confirm or reject the hypothesized causalities.A.A.R.-H. was funded by a Formación de Personal de Investigación grant (BES-2010-035013; Ministerio de Economía y Competitividad [MINECO], Spanish government). Financial support was obtained from the projects CGL-2009-10883-C02-02 and CGL2012-40229-C02-01 (MINECO).Peer Reviewe
The level of an intracellular antioxidant during development determines the adult phenotype in a bird species: a potential organizer role for glutathione
Life-history traits are often involved in trade-offs whose outcome would depend on the availability of resources but also on the state of specific molecular signals. Early conditions can influence trade-offs and program the phenotype throughout the lifetime, with oxidative stress likely involved in many taxa. Here we address the potential regulatory role of a single intracellular antioxidant in lifehistory trade-offs. Blood glutathione levels were reduced in a large
sample of birds (zebra finch Taeniopygia guttata) during development using the synthesis inhibitor buthionine sulfoximine (BSO). Results revealed several modifications in the adult phenotype. BSO-treated nestlings showed lower glutathione and plasma antioxidant levels. In adulthood, BSO birds endured greater oxidative damage in erythrocytes but stronger expression of a sexual signal. Moreover, adult BSO females also showed weaker resistance to oxidative stress but were heavier and showed better body condition. Results suggest that low glutathione values during growth favor the investment in traits that should improve fitness returns, probably in the form of early reproduction. Higher oxidative stress in adulthood may be endured if this cost is paid later in life. Either the presence of specific signaling mechanisms or the indirect effect of increased oxidative stress can explain our findings.Ministerio de Economía y Competitividad [MINECO], Spain). Financial support was obtained from the projects CGL-2009-10883-C02-02 and CGL2012-40229-C02-01 (MINECO).Peer Reviewe
La influencia de la actividad física en el rendimiento académico
En la actualidad todos conocemos que la actividad física tiene una relación directa con la salud. Sin embargo, en los últimos tiempos han aumentado los estudios sobre la influencia de la actividad física sobre el rendimiento académico. En este trabajo aclararemos dicha relación en los alumnos de Educación Primaria, para ello, hemos llevado a cabo una revisión bibliográfica de los principales estudios escritos en inglés que tratan dicha asociación y se han contrastado los resultados obtenidos con el fin de sacar conclusiones sobre si la actividad física tiene un efecto beneficioso sobre el rendimiento académico y el tipo de actividad física que puede tener un mayor impacto en dicha relación. Este estudio puede contribuir a mejorar el rendimiento académico en la escuela que es el principal propósito de la enseñanza en la actualidad.Nowdays it is well known that physical activity has a direct connection with health. However, there has been an increasing of the works on the influence of the physical activity over the academic performance. In this work we will try to look out that link in primary education, for this reason we have made a bibliographic review of the main works written in English language which are focused on that connection, the results obtained have been contrasted to get some ideas about if the physical activity is benefit for the academic results and above all which kind of physical activity is better in so relationship. This work can contribute to improve the academic performance at school, which is the main purpose of the teaching today.Grado en Educación Primari
Aprendizaje cooperativo en cursos multidisciplinares
La enseñanza de contenidos técnicos en grupos multidisciplinares es una tarea compleja debido a la diversidad de los conocimientos iniciales de los alumnos implicados. Sin embargo esta dificultad puede llegar a convertirse en una poderosa herramienta. En este artículo se presenta la experiencia obtenida durante una asignatura de software libre impartida a un grupo multidisciplinar formado por alumnos de distintas carreras técnicas. La base de nuestra propuesta es obligar a los estudiantes a cooperar forzando grupos compuestos por alumnos de diferentes carreras. Este tipo de agrupación obliga a los alumnos a realizar trabajo cooperativo y aprendizaje entre iguales, lo que les permite desarrollar habilidades tanto técnicas como profesionales. Nuestros resultados muestran que con este enfoque se consiguen buenos resultados tanto en el aprendizaje como en la aceptación por parte de los alumnos de la asignatura y del método de enseñanza.Peer Reviewe
Food security measures and labor regulations in the EU-MERCOSUR agreement : an overview of the legal challenges = Medidas de seguridad alimentaria y regulaciones laborales en el Acuerdo UE-MERCOSUR : una visión general de los desafíos legales
Building nations in the XXI century. Celticism, Nationalism and Archaeology in northern Spain: the case of Asturias and León
This investigation presents an overview of ‘Celtic’ nationalism in northern Spain, with the regions of Asturias and León as case studies. In these areas, archaeological narratives have served and still serve to justify
contemporary political agendas. Archaeologists have thus become major actors in the discursive struggles over the past. However, they have become rather naïve and innocent regarding their contemporary public roles and their relationship towards social and political agendas. This
situation has led to a lack of control over the use of their own narratives, which take on a life of their own in the public sphere. Our paper illustrates how archaeology has been used in the construction of contemporary political identities by regionalist and nationalist agents. Whereas nowadays Asturias aims to reinforce selfgovernment,
the objective of León is to become a separate ‘Autonomous
Community’ endowed with a certain degree of self-government
separated from Castile
From general research questions to specific answers: Underspecificity as a source of uncertainty in biological conservation
P. 167-180Species distribution modelling may support ecologists in conservation decision-making. However, the applicability of management recommendations depends on the uncertainty associated to the modelling process. A key source of uncertainty is the underspecificity of the research question. Modelling specific questions is straightforward since they drive clearly the methodological choices about input data and model building. Nevertheless, when the research questions remain underspecific, modellers must choose among a wide spectrum of choices, with each decision sequence driving to a different outcome that explain partially the target question. We show how the underspecificity associated to a general research question about Great Bustard breeding success at geographic scale drives to multiple decision choices, leads to a variety of model outcomes and hampers the identification of specific conservation actions. We ran generalised linear models using multi-model inference on a set of databases built according to specific sequences of methodological choices. Then, we evaluated variations in model performance, complexity (parsimony) and nature of predictors, as well as averaged model predictions and spatial congruence among model outputs. Deviance and parsimony varied widely (11.46% to 83.33% and 7 to 18, respectively), as did model averaged mean predictions in occupied areas, contributing predictors and spatial congruence among outputs (rPearson = 0.44 ± 0.23 for models calibrated in occupied areas; 0.48 ± 0.06 for models calibrated in potential/accessible areas). We recommend to carefully fix research questions and associated methodological options through collaborative working frameworks to conceptualize modelling approaches and, thus, to mitigate problems arising from underspecificity and other forms of uncertainty in conservation applications.S
Changes in plasma biochemistry and body mass during incubation in the Yellow-legged Gull
The >Incubatory Reserves Constancy> hypothesis asserts that incubation could be a departure from breeding stress that allows for the maintenance or recovery of body reserves after laying effort (females) or territory defense (males) in those species with bi-parental incubation such as gulls. The plasma composition and body mass of incubating Yellow-legged Gulls (Larus cachinnans) were analyzed and related to the number of days after egg-laying. Female gulls showed an increase in uric acid and cholesterol levels, whereas males showed only an increase in uric acid values throughout this period. Moreover, females increased while males maintained their body masses. These results could reflect a recovery process after the laying effort supporting the Incubatory Reserves Constancy hypothesis in females. Uric acid and urea levels are positively correlated to body condition in Yellow-legged Gulls, which could be the result of a change in diet composition. This disagrees with recent findings on body composition in incubating gulls and could be related to variations in food availability among populations or years, and could reflect flexibility in the investment devoted by each sex.Peer Reviewe
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