249 research outputs found
Variation in plasma oxidative status and testosterone level in relation to egg-eviction effort and age of brood-parasitic common cuckoo nestlings
To avoid competition for parental care, brood-parasitic Common Cuckoo (Cuculus canorus) nestlings evict all of the host's eggs and nestlings within a few days after hatching. Little is known about the physiological effects of eviction behavior on the cuckoo nestling's oxidative balance or about age-related variation in plasma oxidative status and testosterone level of developing birds. We examined whether the cuckoo nestling's plasma oxidative status was related to prior effort in eviction and quantified variation in the level of reactive oxygen metabolites, of nonenzymatic antioxidant capacity, and of testosterone concentration in plasma at various phases of the cuckoo's development. Levels of both reactive oxygen metabolites and antioxidant capacity were greater in older than in younger nestlings, suggesting that younger nestlings effectively counterbalance their increased production of free radicals, whereas, near fledging, levels of reactive oxygen metabolites increase despite improved antioxidant capacity. Possibly, overall energy expenditure increases with age and elevates the production of reactive oxygen species to a rate higher than what the antioxidant system could eliminate. Plasma testosterone level was the highest at nestlings' intermediate phase of growth. High levels of testosterone may be required during the period of fastest growth, and when the growth rate levels off near fledging, testosterone levels may also decline. Cuckoo chicks that evicted more host eggs from steeper nests had higher plasma levels of reactive oxygen metabolites shortly after the eviction period, suggesting that eviction is costly in terms of an increased level of oxidative stress. Para evitar la competencia por el cuidado parental, los polluelos parĂĄsitos de nidada de Cuculus canorus desalojan todos los huevos y los polluelos del hospedador a los pocos dĂas despuĂ©s de la eclosiĂłn. Se sabe poco sobre los efectos fisiolĂłgicos del comportamiento de desalojo en el balance oxidativo de los polluelos de C. canorus o sobre la variaciĂłn en el estatus oxidativo del plasma y el nivel de testosterona relacionado con la edad de las aves en desarrollo. Examinamos si el estatus oxidativo del plasma de los polluelos de C. canorus se relacionaba con un esfuerzo previo de desalojo y cuantificamos la variaciĂłn en el nivel de metabolitos reactivos de oxĂgeno, la capacidad antioxidante no enzimĂĄtica y la concentraciĂłn de testosterona en el plasma en varias fases del desarrollo de C. canorus. Tanto los niveles de metabolitos reactivos de oxĂgeno como la capacidad antioxidante fueron superiores en los polluelos de mayor edad que en los mĂĄs jĂłvenes, lo que sugiere que los polluelos de menor edad contrarrestan eficazmente el aumento de la producciĂłn de radicales libres, mientras que, cuando se aprĂłximan al abandono del nido, los niveles de metabolitos reactivos de oxĂgeno aumentan a pesar de una mejora en la capacidad antioxidante. Posiblemente, el gasto total de energĂa se incrementa con la edad, elevĂĄndose la producciĂłn de formas reactivas de oxĂgeno a una tasa mayor de la que el sistema antioxidante puede eliminar. El nivel de testosterona en el plasma fue mĂĄximo en la fase intermedia del crecimiento de los polluelos. Pueden requerirse altos niveles de testosterona durante el perĂodo de mayor crecimiento y, cuando la tasa de crecimiento se estabiliza cerca del abandono del nido, los niveles de testosterona tambiĂ©n podriĂĄn disminuir. Los polluelos de C. canorus que desalojaron mĂĄs huevos del hospedador en nidos con una estructura mĂĄs empinada tuvieron niveles de plasma de metabolitos reactivos de oxĂgeno en plasma mĂĄs altos poco despuĂ©s del perĂodo de desalojo, sugiriendo que el desalojo es costoso en tĂ©rminos de un incremento en el nivel de estrĂ©s oxidativo
Academic freedom in Europe: time for a Magna Charta?
This paper is a preliminary attempt to establish a working definition of academic freedom for the European Union states. The paper details why such a definition is required for the European Union and then examines some of the difficulties of defining academic freedom. By drawing upon experience of the legal difficulties beset by the concept in the USA and building on previous analyses of constitutional and legislative protection for academic freedom, and of legal regulations concerning institutional governance and academic tenure, a working definition of academic freedom is then derived. The resultant definition which, it is suggested, could form the basis for a European Magna Charta Libertatis Academicae, goes beyond traditional discussions of academic freedom by specifying not only the rights inherent in the concept but also its accompanying duties, necessary limitations and safeguards. The paper concludes with proposals for how the definition might be tested and carried forward
The nuanced nature of work quality : evidence from rural Newfoundland and Ireland
This article explores the relationship between job and work quality and argues that while it is important to examine job quality, to understand workersâ experiences fully, the focus should be on the broader concept of work quality, which places the job against its wider socio-economic context. Based on the experiences of 88 rural workers gathered via interviews in Newfoundland and Ireland, it appears that the same or similar jobs can be regarded very differently depending upon the context in which they are embedded, as people at different locations and/or stages of life have an individual set of aspirations, expectations and life experiences. The study found that the factors that affect work quality are moulded by broader aspects of life â family, friends, community, lifestyle and past experiences â that shape an individual
Em-âpowering' niche innovations: learning from cycling inequalities
This paper aims to situate power in âniche innovationsâ through an investigation of cycling inequalities in the city of Birmingham. Much research has focused on the sustainability and innovation potential of cycling. However, debates usually revolve around the power relations between cycling and the dominant automobility regime, thus ignoring the possible inequalities embedded within niches. This paper aims to contribute to such analyses by unfolding the multiple inequalities and relations of exclusion that can be embedded in the practice of cycling. Drawing on Mobilities research for the EPSRC Liveable Cities programme, it focuses on the car-dependent city of Birmingham, in order to explore cycling as a practice with various socio-material, infrastructural, political and economic entanglements that can embed, reproduce or generate new socio-spatial inequalities, processes of gentrification and immobilities. Through such analysis, this paper aims to situate power in examining niche innovations. However, it also aims to underline that understanding and addressing such inequalities are central for not only locating cycling in the centre of developing a more sustainable mobility future, but also enabling a more sustainable future for cycling itself
Can the outcome of pelvic-floor rehabilitation in patients with fecal incontinence be predicted?
Purpose: Pelvic-floor rehabilitation does not provide the same degree of relief in all fecal incontinent patients. We aimed at studying prospectively the ability of tests to predict the outcome of pelvic-floor rehabilitation in patients with fecal incontinence. Materials and methods: Two hundred fifty consecutive patients (228 women) underwent medical history and a standardized series of tests, including physical examination, anal manometry, pudendal nerve latency testing, anal sensitivity testing, rectal capacity measurement, defecography, endoanal sonography, and endoanal magnetic resonance imaging. Subsequently, patients were referred for pelvic-floor rehabilitation. Outcome of pelvic-floor rehabilitation was quantified by the Vaizey incontinence score. Linear regression analyses were used to identify candidate predictors and to construct a multivariable prediction model for the posttreatment Vaizey score. Results: After pelvic-floor rehabilitation, the mean baseline Vaizey score (18, SD±3) was reduced with 3.2 points (p<0.001). In addition to the baseline Vaizey score, three elements from medical history were significantly associated with the posttreatment Vaizey score (presence of passive incontinence, thin stool consistency, primary repair of a rupture after vaginal delivery at childbed) (R2, 0.18). Th
Affective practices, care and bioscience: a study of two laboratories
Scientific knowledge-making is not just a matter of experiments, modelling and fieldwork. It also involves affective, embodied and material practices (Wetherell 2012) which can be understood together as 'matters of care' (Puig de la Bellacasa, 2011). In this paper we explore how affect spans and connects material, subjective and organisational practices, focusing in particular on the patterns of care we encountered in an observational study of two bioscience laboratories. We explore the preferred emotional subjectivities of each lab and their relation to material practice. We go on to consider flows and clots in the circulation of affect and their relation to care through an exploration of belonging and humour in the labs. We show how being a successful scientist or group of researchers involves a careful choreography of affect in relation to materials, colleagues and others to produce scientific results, subjects and workplaces. We end by considering how thinking with care troubles dominant constructions of scientific practice, successful scientific selves and collectives
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