947 resultados para Walter Raleigh
Resumo:
Divergence dating studies, which combine temporal data from the fossil record with branch length data from molecular phylogenetic trees, represent a rapidly expanding approach to understanding the history of life. National Evolutionary Synthesis Center hosted the first Fossil Calibrations Working Group (3–6 March, 2011, Durham, NC, USA), bringing together palaeontologists, molecular evolutionists and bioinformatics experts to present perspectives from disciplines that generate, model and use fossil calibration data. Presentations and discussions focused on channels for interdisciplinary collaboration, best practices for justifying, reporting and using fossil calibrations and roadblocks to synthesis of palaeontological and molecular data. Bioinformatics solutions were proposed, with the primary objective being a new database for vetted fossil calibrations with linkages to existing resources, targeted for a 2012 launch.
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An array of substrates link the tryptic serine protease, kallikrein-related peptidase 14 (KLK14), to physiological functions including desquamation and activation of signaling molecules associated with inflammation and cancer. Recognition of protease cleavage sequences is driven by complementarity between exposed substrate motifs and the physicochemical signature of an enzyme's active site cleft. However, conventional substrate screening methods have generated conflicting subsite profiles for KLK14. This study utilizes a recently developed screening technique, the sparse matrix library, to identify five novel high-efficiency sequences for KLK14. The optimal sequence, YASR, was cleaved with higher efficiency (k(cat)/K(m)=3.81 ± 0.4 × 10(6) M(-1) s(-1)) than favored substrates from positional scanning and phage display by 2- and 10-fold, respectively. Binding site cooperativity was prominent among preferred sequences, which enabled optimal interaction at all subsites as indicated by predictive modeling of KLK14/substrate complexes. These simulations constitute the first molecular dynamics analysis of KLK14 and offer a structural rationale for the divergent subsite preferences evident between KLK14 and closely related KLKs, KLK4 and KLK5. Collectively, these findings highlight the importance of binding site cooperativity in protease substrate recognition, which has implications for discovery of optimal substrates and engineering highly effective protease inhibitors.
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Decade after decade, violence against women has gained more attention from scholars, policy makers, and the general public. Social scientists in particular have contributed significant empirical and theoretical understandings to this issue. Strikingly, scant attention has focused on the victimization of women who want to leave their hostile partners. This groundbreaking work challenges the perception that rural communities are safe havens from the brutality of urban living. Identifying hidden crimes of economic blackmail and psychological mistreatment, and the complex relationship between patriarchy and abuse, Walter S. DeKeseredy and Martin D. Schwartz propose concrete and effective solutions, giving voice to women who have often suffered in silence.
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In Violence Against Women, award-winning author Walter S. DeKeseredy offers a passionate but well-documented sociological overview of a sobering problem. He starts by outlining the scope of the challenge and debunks current attempts to label intimate violence as gender neutral. He then lays bare the structural practices that sustain this violence, leading to a discussion of long- and short-term policies to address the issue. DeKeseredy includes an examination of male complicity and demonstrates how boys and men can change their roles. Throughout, he responds to myths that dismiss threats to women's health and safety and provides an impassioned call to action for women, men, and policymakers.
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This paper considers VECMs for variables exhibiting cointegration and common features in the transitory components. While the presence of cointegration between the permanent components of series reduces the rank of the long-run multiplier matrix, a common feature among the transitory components leads to a rank reduction in the matrix summarizing short-run dynamics. The common feature also implies that there exists linear combinations of the first-differenced variables in a cointegrated VAR that are white noise and traditional tests focus on testing for this characteristic. An alternative, however, is to test the rank of the short-run dynamics matrix directly. Consequently, we use the literature on testing the rank of a matrix to produce some alternative test statistics. We also show that these are identical to one of the traditional tests. The performance of the different methods is illustrated in a Monte Carlo analysis which is then used to re-examine an existing empirical study. Finally, this approach is applied to provide a check for the presence of common dynamics in DSGE models.
Resumo:
Forecasts generated by time series models traditionally place greater weight on more recent observations. This paper develops an alternative semi-parametric method for forecasting that does not rely on this convention and applies it to the problem of forecasting asset return volatility. In this approach, a forecast is a weighted average of historical volatility, with the greatest weight given to periods that exhibit similar market conditions to the time at which the forecast is being formed. Weighting is determined by comparing short-term trends in volatility across time (as a measure of market conditions) by means of a multivariate kernel scheme. It is found that the semi-parametric method produces forecasts that are significantly more accurate than a number of competing approaches at both short and long forecast horizons.
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Several forms of elliptic curves are suggested for an efficient implementation of Elliptic Curve Cryptography. However, a complete description of the group law has not appeared in the literature for most popular forms. This paper presents group law in affine coordinates for three forms of elliptic curves. With the existence of the proposed affine group laws, stating the projective group law for each form becomes trivial. This work also describes an automated framework for studying elliptic curve group law, which is applied internally when preparing this work.
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Online gaming environments feature a number of challenging regulatory issues; a diverse player base, uneven power relationship, and lack of real dispute resolution mechanisms. By conducting an ethnographic study of the online environment Eve Online, and using as a comparative the offshore gaming industry, I consider how we might look to regulate, and resolve disputes within, online gaming environments. In doing so, I adopted a novel approach to the study of online gaming environments - that of norms - which gave significance not only to the terms of service dictated by platform providers and their legal advisors, but also to the social and ludic limitations and affordances players constructed themselves. Finally, through an account of the evolution of regulatory mechanisms and dispute resolution in the offshore gambling industry, I consider how an environment which features much in common with online gaming environments overcame a number of these challenges within the last 10-15 years, and what lessons might be taken from those experiences and applied to contemporary online gaming environments.
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If the current discourses of progress are to be believed, the new or social media promise a kaleidoscope of opportunity for connecting and informing citizens. This is by allegedly revitalizing the fading legitimacy and practice of institutions and providing an agent for social interaction. However, as social media adoption has increased, it has revealed a wealth of contradictions both of its own making and reproduction of past action. This has created a crisis for traditional media as well as for public relations. For example, social media such as WikiLeaks have bypassed official channels about government information. In other cases, social media such as Facebook and Twitter informed BBC coverage of the Rio Olympics. Although old media are unlikely to go away, social media have had an impact with several large familybased media companies collapsing or being reintegrated into the new paradigm. To use Walter Lippman’s analogy of the phantom public, the social media contradictorily serve to both disparate the phantom in part and reinforce it...
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Queen's Park in Maryborough is one of many public gardens established in the nineteenth century in Queensland: in Brisbane, Ipswich, Toowoomba, Warwick, Rockhampton, Mackay, Townsville, Cairns and Cooktown. They were created primarily as places of horticultural experimentation, as well as for recreational purposes. They formed a local area network, with the Brisbane Botanic Garden and the Government Botanist, Walter Hill, at the centre – at least in the 1870s. From here, the links extended to other botanic gardens in Australia, and beyond Australia to the British colonial network managed through the Royal Botanic Gardens (RBG), Kew. It was an informal network, supplying a knowledge of basic economic botany that founded many tropical agricultural industries and also provided much-needed recreational, educational and inspirational opportunities for colonial newcomers and residents. The story of these parks, from the time when they were first set aside as public reserves by the government surveyors to the present day, is central to the history of urban planning in regional centres. This article provides a statewide overview together with a more in-depth examination of Maryborough's own historic Queen's Park.