989 resultados para Historical Methodology
Resumo:
Malone, C.A.T. and S.K.F. Stoddart, . (co-authored).
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A National Frog Survey of Ireland is planned for spring 2011. We conducted a pilot survey of 25 water bodies in ten 0.25 km2 survey squares in Co. Mayo during spring 2010. Drainage ditches were the most commonly available site for breeding and, generally, two 100 m stretches of ditch were surveyed in each square. The restricted period for peak spawning activity renders any methodology utilizing only one site visit inherently risky. Consequently, each site was visited three times from late March to early April. Occurrence of spawn declined significantly from 72 % to 44 % between the first and third visit whilst the overall occurrence of spawn at all sites was 76 %. As the breeding season advanced, spawn either hatched or was predated and, therefore, disappeared. In those water bodies where spawning was late, however, greater densities of spawn were deposited than in those sites where breeding was early. Consequently, spawn density and estimated frog density did not differ significantly between site visits. Future surveys should nevertheless include multiple site visits to avoid biased estimation of species occurrence and distribution. Ecological succession was identified as the main threat present at 44 % of sites.
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The role of rhodopsin as a structural prototype for the study of the whole superfamily of G protein-coupled receptors (GPCRs) is reviewed in an historical perspective. Discovered at the end of the nineteenth century, fully sequenced since the early 1980s, and with direct three-dimensional information available since the 1990s, rhodopsin has served as a platform to gather indirect information on the structure of the other superfamily members. Recent breakthroughs have elicited the solution of the structures of additional receptors, namely the beta 1- and beta 2-adrenergic receptors and the A(2A) adenosine receptor, now providing an opportunity to gauge the accuracy of homology modeling and molecular docking techniques and to perfect the computational protocol. Notably, in coordination with the solution of the structure of the A(2A) adenosine receptor, the first "critical assessment of GPCR structural modeling and docking" has been organized, the results of which highlighted that the construction of accurate models, although challenging, is certainly achievable. The docking of the ligands and the scoring of the poses clearly emerged as the most difficult components. A further goal in the field is certainly to derive the structure of receptors in their signaling state, possibly in complex with agonists. These advances, coupled with the introduction of more sophisticated modeling algorithms and the increase in computer power, raise the expectation for a substantial boost of the robustness and accuracy of computer-aided drug discovery techniques in the coming years.
Resumo:
Purpose – The purpose of this paper is to identify the main practitioners, goods, customers and locations of secondhand marketing activities in late medieval England. It questions how important was the economic role played by such markets and what was the interaction with more formal market structures?
Design/methodology/approach – A broad range of evidence was examined, covering the period from 1200 to 1500: regulations, court rolls, wills, manorial accounts, literature, and even archaeology. Such material often provided mere scraps of information about marginal marketing activity and it was important to recognise the severe limitations of the evidence. Nevertheless, a wide survey of the available sources can give us an insight into medieval attitudes towards such trade, as well as reminding us that much marketing activity occurred beyond the reach of the surviving documentation.
Findings – Late medieval England had numerous outlets for secondhand items, from sellers of used clothes and furs who wandered the marketplaces to craftsmen who recycled and mended old materials. Secondhand marketing was an important part of the medieval makeshift economy, serving not only the needs of the lower sectors of society but also those aspiring to a higher status. However, it is unlikely that such trade generated much profit and the traders were often viewed as marginal, suspicious and even fraudulent.
Originality/value – There is a distinct lack of research into the extent of and significance of medieval secondhand marketing, which existed in the shadowy margins of formal markets and is thus poorly represented in the primary sources. A broad-based approach to the evidence can highlight a variety of important issues, which impact upon the understanding of the medieval English economy.