Environmental conditions during early life accelerate the rate of senescence in a short-lived passerine bird

Environmental conditions experienced in early life may shape subsequent phenotypic traits including life history. We investigated how predation risk caused by domestic cats (Felis silvestris catus) and local breeding density affected patterns of reproductive and survival senescence in Barn Swallows (Hirundo rustica) breeding semicolonially in Denmark. We recorded the abundance of cats and the number of breeding pairs at 39 breeding sites during 24 years and related these to age-specific survival rate and reproductive senescence to test predictions of the life history theory of senescence. We found evidence for actuarial senescence for the first time in this species. Survival rate increased until reaching a plateau in midlife and then decreased later. We also found that survival rate was higher for males than females. Local breeding density or predation risk did not affect survival as predicted by theory. Barn Swallows with short lives did not invest more in reproduction in early life, inconsistent with expectations for trade-offs between reproduction and survival as theory suggests. However, we found that the rate of reproductive decline during senescence was steeper for individuals exposed to intense competition, and predation pressure accelerated the rate of reproductive senescence, but only in sites with many breeding pairs. These latter results are in accordance with one of the predictions suggested by the life history theory of aging. These results emphasize the importance of considering intraspecific competition and interspecific interactions such as predation when analyzing reproductive and actuarial senescence

he problem of the constitution of intersubjectivity in Husserl’s thinking

Indexación: Web of Science; Scielo.La teoría de la intersubjetividad, desarrollada por Husserl en sus Meditaciones Cartesianas, da la oportunidad para desmontar el mecanismo que equilibra en una falsa armonía el idealismo y el realismo implícito en su filosofía. La Quinta meditación cartesiana, que aborda el problema del otro en un momento de acentuado idealismo, revela como una contradicción la tracción a la que está sujeta la experiencia del otro entre dos tendencias: restituir el otro en mí y constituirlo como otro. Paradoja que está latente en toda su filosofía y que lleva a que la Quinta meditación cartesiana “estalle” sin proporcionar una respuesta satisfactoria1. Sabemos que al publicarse sus Cartesianischen Meditationen Husserl era un pensador que había alcanzado cierta notoriedad y sus textos circulaban en el ambiente académico con particular interés. En dicha época nos encontramos con un Husserl ya maduro cuyo método de pensamiento, la fenomenología, se había aquilatado alcanzando un cierto reconocimiento. En virtud de ello, para dicha época se habían formulado las primeras críticas a su pensamiento, acusándolo de solipsismo trascendental. Él mismo hace referencia a tales críticas en sus Meditaciones: “Cuando yo el que medito, por medio de una epoye fundamental fenomenológica me reduzco a mi absoluto ego trascendental. ¿No me he convertido por ello en solus ipse y no lo sigo siendo mientras bajo el título de fenomenología efectúo una consecuente explicitación de mi mismo?” (Husserl, Meditaciones, 119). Con este propósito, en las Meditaciones cartesianas, Husserl no solo intenta realizar una exposición clara y concentrada de su pensamiento, sino que fundamentalmente se hace cargo de esta crítica realizada en defensa de sus ideas. Es precisamente en dicho espíritu que Husserl aborda el problema de lo social en Descubrimiento de la esfera del ser trascendental como intersubjetividad monádica.http://ref.scielo.org/4yhj2

Mujeres, imaginario corporal y prácticas sexuales. Vivencias de la corporalidad y el erotismo

La formación de un sujeto reconocido por este sistema es un largo proceso de modelar y cincelar bajo las prescripciones dominantes y con las herramientas permitidas. La constitución de un sujeto, la conformación de una identidad van indisolublemente ligadas a un cuerpo, que es signifi cado previamente por la cultura en que se nace. Este yo cuerpo, esta corporalidad subjetivada queda inscrita en una cultura hegemónica heteronormativa, donde el cuerpo en el que se nace marca las vías del deseo y determina la identidad

Une dialectique negative levinassienne?

Levinas est traditionnellement perçu comme une voix critique à propos de la pensée de la totalité de Hegel et, ainsi, comme un philosophe qui cherche à dénoncer la négation de toute différence dans la pensée de l’identité, que ce soit dans l’unité de la vie, de l’esprit, du savoir ou du concept. Or, le paradoxe de Levinas est de critiquer Hegel tout en réinterprétant et en s’appropriant certains de ses concepts fondamentaux. Plus particulièrement, c'est le cas avec la radicalisation de la puissance du négatif. Il s’agit donc de s’interroger sur l’effort de Levinas pour développer une forme intrinsèque à la dialectique hégélienne que Hegel aurait entrevue sans développer dans sa philosophie, encore trop enracinée dans une métaphysique que Levinas tente de quitter. Ce faisant, il s’agit d’éclaircir si l’on peut même parler d’une dialectique négative lévinassienne.Levinas es considerado tradicionalmente como una voz crítica del pensamiento de la totalidad de Hegel y, por tanto, como un filósofo que busca denunciar la negación de toda diferencia en el pensamiento de la identidad, ya sea en la unidad de la vida, de la mente, del conocimiento o del concepto. La paradoja de Levinas es que critica a Hegel mientras reinterpreta y se apropia de algunos de sus conceptos fundamentales. Es el caso de la radicalización del poder de lo negativo. Se trata, pues, de cuestionar el esfuerzo de Levinas por desarrollar una forma intrínseca a la dialéctica hegeliana que Hegel habría vislumbrado sin desarrollar en su filosofía, todavía demasiado arraigada en una metafísica que Levinas intenta dejar atrás. El propósito es aclarar si se puede hablar de una dialéctica negativa levinasiana

La dualidad de las capas medias, la apatía y la sustentabilidad socio-política en Chile

Desde hace treinta y cinco años los quintiles intermedios de la estratificación social chilena se han incrementado considerablemente, generando cambios en nuestra cultura política. A partir de una investigación conjunta, este artículo explora el significado de la dualidad político-cultural que ha aparecido en las nuevas capas medias. Su crecimiento y el mejoramiento de las condiciones de vida las ha dividido en dos orientaciones contradictorias: unas dirigidas hacia el sector privado y las otras hacia el Estado que denominaremos “emergentes” y “tradicionales”. Las prácticas del primer sector, nacidas del neoliberalismo, han privilegiado los códigos del consumismo y del mercado. Las tradicionales, en cambio, formadas desde fines del siglo XIX junto a la denominada “clase obrera”, optaron por “estilos meritocráticos” institucionalizando pautas democráticas, articuladoras de compromisos socio-políticos de protección. Actualmente, las señales emergentes tienden a predominar, favorecidas por la contradicción de estilos y por el peso de la institucionalidad vigente. Su lógica instaurada desde la Constitución de 1980, bloquea las formas tradicionales, haciendo hegemónicas a las emergentes. La apatía socio-política actual, coincide con la aparición de estilos contrapuestos posiblemente relacionados con la desarticulación social. Esa dualidad, sumada a la obstaculización institucional hace pensar que la desarmonía puede favorecer el aislamiento del escenario político respecto de la sociedad, restándole sustentabilidad al sistema democrático

Movements of juvenile Bonelli's eagles aquila Fasciata during dispersal

Capsule Juvenile non-breeding males and females explored surrounding areas, returned to breeding areas, and settled in temporary settlement areas. Aims To describe movement patterns of juvenile Bonelli's Eagles during the transient phase of dispersal. Methods Radiotelemetry data from 16 individuals were studied. Results Six main temporary settlement areas were located. No sex differences were found in the time to first departure from natal areas, time to the first temporary settlement, or time of the first return to natal areas. Juvenile eagles did not settle in temporary settlement areas until they were, on average, 245 days old. In general, males and females did not differ in their movement patterns during the early part of the dispersal period. However, after approximately 500 days males spent 60.8% of their time exploring surrounding areas, probably with the aim of searching for vacant territories or mates, whereas females of the same age devoted 26.7% of their time to exploration. Conclusion Movements and use of sites during the transient phase of dispersal are complex. They have important implications for the conservation of this endangered species. © 2009 British Trust for Ornithology.Peer Reviewe

Maintenance of Microbial Cooperation Mediated by Public Goods in Single- and Multiple-Trait Scenarios

Microbes often form densely populated communities, which favor competitive and cooperative interactions. Cooperation among bacteria often occurs through the production of metabolically costly molecules produced by certain individuals that become available to other neighboring individuals; such molecules are called public goods. This type of cooperation is susceptible to exploitation, since nonproducers of a public good can benefit from it while saving the cost of its production (cheating), gaining a fitness advantage over producers (cooperators). Thus, in mixed cultures, cheaters can increase in frequency in the population, relative to cooperators. Sometimes, and as predicted by simple game-theoretic arguments, such increases in the frequency of cheaters cause loss of the cooperative traits by exhaustion of the public goods, eventually leading to a collapse of the entire population. In other cases, however, both cooperators and cheaters remain in coexistence. This raises the question of how cooperation is maintained in microbial populations. Several strategies to prevent cheating have been studied in the context of a single trait and a unique environmental constraint. In this review, we describe current knowledge on the evolutionary stability of microbial cooperation and discuss recent discoveries describing the mechanisms operating in multiple-trait and multiple-constraint settings. We conclude with a consideration of the consequences of these complex interactions, and we briefly discuss the potential role of social interactions involving multiple traits and multiple environmental constraints in the evolution of specialization and division of labor in microbes.info:eu-repo/semantics/publishedVersio

Mutualistic interaction between Salmonella enterica and Aspergillus niger and its effects on Zea mays colonization

Salmonella Typhimurium inhabits a variety of environments and is able to infect a broad range of hosts. Throughout its life cycle, some hosts can act as intermediates in the path to the infection of others. Aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia. Recently, S. Typhimurium was shown to establish biofilms on the hyphae of A. niger. In this work, we have found that this interaction is stable for weeks without a noticeable negative effect on either organism. Indeed, bacterial growth is promoted upon the establishment of the interaction. Moreover, bacterial biofilms protect the fungus from external insults such as the effects of the anti-fungal agent cycloheximide. Thus, the Salmonella–Aspergillus interaction can be defined as mutualistic. A tripartite gnotobiotic system involving the bacterium, the fungus and a plant revealed that co-colonization has a greater negative effect on plant growth than colonization by either organism in dividually. Strikingly, co-colonization also causes a reduction in plant invasion by S. Typhimurium. This work demonstrates that S. Typhimurium and A. niger establish a mutualistic interaction that alters bacterial colonization of plants and affects plant physiology

Evolutionary Mechanisms Shaping the Maintenance of Antibiotic Resistance

The deposited review is a post-print version and has been submitted to peer review.This publication hasn't any creative commons license associated.This deposit is composed by the review, and it hasn't any supplementary materials associated.The publication deposited was in a state of Epub Ahead of Print, at the time when the upload was made.Antibiotics target essential cellular functions but bacteria can become resistant by acquiring either exogenous resistance genes or chromosomal mutations. Resistance mutations typically occur in genes encoding essential functions; these mutations are therefore generally detrimental in the absence of drugs. However, bacteria can reduce this handicap by acquiring additional mutations, known as compensatory mutations. Genetic interactions (epistasis) either with the background or between resistances (in multiresistant bacteria) dramatically affect the fitness cost of antibiotic resistance and its compensation, therefore shaping dissemination of antibiotic resistance mutations. This Review summarizes current knowledge on the evolutionary mechanisms influencing maintenance of resistance mediated by chromosomal mutations, focusing on their fitness cost, compensatory evolution, epistasis, and the effect of the environment on these processes.PD and RB were supported by Fundação para a Ciência e Tecnologia (FCT), fellowships SFRH/BPD/118474/2016 and SFRH/BPD/109517/2015, respectively. Current research is supported by project JPIAMR/0001/2016-ERA NET and ONEIDA project (LISBOA-01-0145-FEDER-016417) co-funded by FEEI – ‘Fundos Europeus Estruturais e de Investimento’ from ‘Programa Operacional Regional Lisboa 2020’, and by national funds from FCT – ‘Fundação para a Ciência e a Tecnologia’.info:eu-repo/semantics/acceptedVersio

Sex determination in booted eagles (Hieraaetus pennatus) using molecular procedures and discrimiant function analysis

We studied a breeding population of Booted Eagles (Hieraaetusp ennatus)i n Doñana National Park (southwestern Spain) to develop a method of determining the sex of an individual based on the use of iscriminant functions. Because there are size differences between age classes and sexes of eagles, we developed two different discriminant functions for each age group. Our discriminant function method approached 100% accuracy in correctly aging individuals using forearm length and body massa s predictor variables.S ex of young eaglesw as also determined with 98.8% accuracyu sing forearm, tail, bill, and tarsus lengthsPeer reviewe