992 resultados para 7140-244
Resumo:
In many bird species the sex ratio of adults is male-biased, which is likely to have consequences for the ecology as well as for the conservation of a species. For example, when some males remain unpaired in a population, there should be strong selection on behavioural traits that enhance pairing success. A surplus of males is also likely to have important implications for the interpretation of breeding bird survey data. In our study population of Nightingales Luscinia megarhynchos, about half of the males stayed unpaired, suggesting that the number of males encountered singing was greater than the number of breeding pairs. Furthermore, the detectability (the probability of encountering a male singing) of mated males was only two-thirds that of unmated males when censused in the morning or late in the breeding season. The relative detectability was more similar early in the season and during the twilight periods before sunrise and after sunset. Males that arrived earlier on the breeding grounds were more successful in attracting a mate than males arriving later. Some of the unmated males deserted their territories and prospected areas up to 4000 m distant, whereas others settled on the study site only late in the season and may actually have changed territories. We suggest that adult sex ratios and the time of the census should be taken into account when interpreting the results of breeding bird surveys.
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The determination of chloride impurities in water miscible and water immiscible ionic liquids has been explored using ion chromatography (IC) and cathodic stripping voltammetry (CSV). This paper shows the first quantification of chloride in [NTf2](-) based ILs. The parameters investigated include sample preparation, solvent effect, sample stability, and limit of quantification (LOQ).
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Here we describe the structural and functional characterization of a novel myotropic peptide, sauvatide, from the skin secretion of the waxy monkey frog, Phyllomedusa sauvagei. Sauvatide is a C-terminally amidated decapeptide with the following primary structure – LRPAILVRTKamide – monoisotopic mass 1164.77 Da, which was found to contract the smooth muscle of rat urinary bladder with an EC50 of 2.2 nM. The sauvatide precursor, deduced from cloned skin cDNA, consists of 62 amino acid residues with a single copy of sauvatide located near the C-terminus. The mature peptide is generated from the precursor by cleavage at a classical –KR-cleavage site located proximal to the N-terminus and by removal of a –GKGK sequence at the C-terminus, the first glycyl residue acting as amide donor. Amphibian skin secretions thus continue to be a source of novel and potent biologically active peptides acting through functional targets in mammalian tissues.
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La doctrina de la Proliferación teórica de Paul Karl Feyerabend ha sido interpretada por sus especialistas como un intento de salvaguardar el ideal del progreso científico. Aunque tales estudios hacen justicia, en parte, a la intencionalidad de nuestro filósofo no explicitan la crítica fundamental que implica para Feyerabend el pluralismo teórico. La proliferación teórica constituye en sí misma una reductio ad absurdum de los distintos intentos del positivismo lógico y del racionalismo crítico por definir la ciencia a expensas de lo metafísico. Este artículo presenta la proliferación teórica como una reivindicación del papel positivo que ocupa la metafísica en el quehacer científico. Se consigna la defensa que hace Feyerabend de la metafísica en cuanto que ésta constituye la posibilidad de superar el conservadurismo conceptual, aumentar de contenido empírico de la ciencia y recuperar el valor descriptivo de las teorías científicas.
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Three Entries: Peacelines; Public Housing in Northern Ireland in the Twentieth Century; Interpretive Centres, NI Peacelines, NI Social Housing
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We anounce results on the continuity of the map sending a masa-bimodule to its support. The proofs of the results will be published elsewhere.
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In 1990, Juan Antonio Ramírez made known his iconological paranoiac method to the academic world. It is a system devised to study Dalí´s work, born of happy matrimony between the catalonian artist´s critical paranoiac method and the first iconographic school of Warburg and Panofsky. What, at first sight, seemed to be an extravagant methodology with little academic credibility, turned out to be, by going forward in time, an effective research method when analyzing Dali´s initial works. It is no wonder that, at the beginning of XXI century, this hybridization between Dalí´s and Panofsky’s methods, were regarded as a strange and nonsensical idea. Nevertheless, twenty years after, blatant examples have been noted, which endorse the advantages of this new system for “iconographic” study. As usual, this new contribution by Juan Antonio Ramirez to art history methodology is called upon to have a successful future survival, in forthcoming generations. This article, attempts to analyze this method, inquiring into the validity, effectiveness and practical utility.
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This article makes a case for the inclusion of subcultural capital as an indictor of social capital networks in the lives of teenagers. It does so by critiquing approaches that assume that adult measures of social capital can be nonproblematically extended to account for stocks of social capital held by younger generations. To illustrate the fallacy of this approach, this article draws on data from the 2003 Northern Ireland Young Life and Times Survey (NIYLTS) and the indicators used to explore the relevance of social capital in the lives of teenagers. By ignoring concepts such as subcultural capital, surveys such as the NILYTS provide partial frameworks for understanding the complexities of young people's links to social capital networks and their inclusive and exclusive effects.
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In this article, I examine Thomas Middleton's Women Beware Women as a response to the particular religio-political context in the years surrounding 1621. The onset of the Thirty Years War in 1618 and the subsequent humiliation of James' son-in-law Frederick, Elector of Palatine, the vexed question of a possible Catholic marriage for Charles, Prince of Wales, the ever present difficulty of Anglo-Catholic relations, particularly with Spain, as well as growing religious factionalism within the Church of England between Calvinists and Arminians: all contributed towards a culturally febrile atmosphere, one to which, as I will argue, Middleton was well placed to respond. Given Middleton's Calvinistic beliefs, I suggest that Women Beware Women offers an acerbic examination of contemporary debates concerning human will, especially women's will, as well as promoting a sceptically apocalyptic anti-Catholic agenda throughout. I also examine the religious language and imagery used to construct Bianca as the whore of Babylon, and argue that her emergence and fall offer a political commentary on the precarious position of the English Church around 1621.