859 resultados para Ask a librarian


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A current induces forces on atoms inside the conductor that carries it. It is now possible to compute these forces from scratch, and to perform dynamical simulations of the atomic motion under current. One reason for this interest is that current can be a destructive force—it can cause atoms to migrate, resulting in damage and in the eventual failure of the conductor. But one can also ask, can current be made to do useful work on atoms? In particular, can an atomic-scale motor be driven by electrical current as it can be by other mechanisms. For this to be possible, the current-induced forces on a suitable rotor must be non-conservative, so that net work can be done per revolution. Here we show that current-induced forces in atomic wires are not conservative and that they can be used, in principle, to drive an atomic-scale waterwheel.

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The most appropriate way to measure the social benefits of conserving built cultural heritage sites is to ask the beneficiaries of conservation interventions how much they would be willing to pay for them. We use contingent valuation - a survey-based approach that elicits willingness to pay (WTP) directly from individuals - to estimate the benefits of a nationwide conservation of built cultural heritage sites in Armenia. The survey was administered to Armenian nationals living in Armenia, and obtained extensive information about the respondents' perceptions of the current state of conservation of monuments in Armenia, described the current situation, presented a hypothetical conservation program, elicited WTP for it, and queried individuals about what they thought would happen to monument sites in the absence of the government conservation program. We posit that respondents combined the information about the fate of monuments provided by the questionnaire with their prior beliefs, and that WTP for the good, or program, is likely to be affected by these updated beliefs. We propose a Bayesian updating model of prior beliefs, and empirically implement it with the data from our survey. We found that uncertainty about what would happen to monuments in the absence of the program results in lower WTP amounts. © 2008 Pion Ltd and its Licensors.

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A pin diode-loaded active doubly periodic flat strip FSS is shown to act as a dynamic screen. It is shown that by means of d.c. bias control, we can utilize the screen in, (1) transmission mode as a dual band electromagnetic shutter, or with the inclusion of a ground plane in reflection mode, (is (2) it dual band refection canceller. (3) an amplitude shift keying (ASK) spatial modulator. The properties of the FSS are characterized using a specially designed parallel plate waveguide simulator that permits normal incidence excitation of the FSS under test. (C) 2009 Wiley Periodicals. Inc. Microwave Opt Technol Lett 51: 2059-2061, 2009; Published online in Wiley Inter-Science (www. interscience.wiley.com). DOI 10.1002/mop.24547

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This article reports on research carried out on 200 child welfare files from the largest welfare authority in Northern Ireland from 1950-1968. The literature review provides a commentary on some of the major debates surrounding child welfare and protection social work from the perspective of its historical development. The report of the research which follows offers an insight into one core, and less well-known period of child welfare history in Northern Ireland between the two Children and Young Persons Acts (1950 & 1968). Using a method of discourse analysis influenced by Michel Foucault, a detailed description of the nature of practice is offered. This paper is offered as a work in progress, with further work being planned for dissemination of more detailed analysis of the method and outcomes. The research seeks to ask a few core questions based on problems identified in the present with our current understandings of child welfare and protection histories. While recognising the limitations of this study and the need for broader analysis of the wider context surrounding child welfare practice at the moment, it is argued that some salient conclusions can be drawn about continuity and discontinuity in practice which are of interest to practitioners and students of child welfare social work.

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Rural areas are recognised for their complex, multi-functional capacities with a range of different interest groups claiming their rights to, and use of, different rural spaces. The current rural development paradigm that is evident across the globe is epitomised by the European LEADER approach. Using evidence from the proposed National Park in Northern Ireland, we ask the question: what is the potential of sustainable rural tourism to contribute to rural development? Within our analysis we consider the scope for adaptive tourism to overcome some of the ongoing challenges that have been identified within the LEADER approach. Four themes are revealed from this analysis: institutional (in)capacity; legitimacy of local groups; navigating between stakeholder interests; and sustainable tourism in practice. These issues, discussed in turn, have clear implications for the new rural development programme.

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Something new is happening to reverse the historical trend of skilled Scots moving to London for career progression. The Scottish population of London and the South East is falling and this despite Scots enjoying continued occupational success within the South East labour market. The authors ask why Scots are leaving the UK's main escalator region and then investigate how these migration changes can best be theorised relative to literature on the mobility of the 'new service class'. Building on Fielding's escalator region hypothesis, the authors report on recent research on longer distance flows out of the UK's main escalator region. They advance the critique of the escalator region hypothesis set out by Findlay et al and ask why people would leave a global city offering good opportunities for occupational mobility. Demographic regime change provides only a partial answer. Other explanations can be found in the changing mobilities of the new service class as they engage in what Smith has defined as 'translocal' and 'transnational' urbanism. The authors argue that Scotland's changing relationship with London and the South East may be representative of a wider set of changes in migration linkages between regional economies and global cities.

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At the outset of a discussion of evaluating digital musical instruments, that is to say instruments whose sound generators are digital and separable though not necessarily separate from their control interfaces (Malloch, 2006), it is reasonable to ask what the term evaluation in this context really means. After all, there may be many perspectives from which to view the effectiveness or otherwise of the instruments we build. For most performers, performance on an instrument becomes a means of evaluating how well it functions in the context of live music making, and their measure of success is the response of the audience to their performance. Audiences evaluate performances on the basis of how engaged they feel they have been by what they have seen and heard. When questioned, they are likely to describe good performances as “exciting,” “skillful,” “musical.” Bad performances are “boring,” and those which are marred by technical malfunction are often dismissed out of hand. If performance is considered to be a valid means of evaluating a musical instrument, then it follows that, for the field of DMI design, a much broader definition of the term “evaluation” than that typically used in human-computer interaction (HCI) is required to reflect the fact that there are a number of stakeholders involved in the design and evaluation of DMIs. In addition to players and audiences, there are also composers, instrument builders, component manufacturers, and perhaps even customers, each of whom will have a different concept of what is meant by “evaluation.”

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Background: Postal and electronic questionnaires are widely used for data collection in epidemiological studies but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response to postal and electronic questionnaires would improve the quality of health research. Objectives: To identify effective strategies to increase response to postal and electronic questionnaires. Search strategy: We searched 14 electronic databases to February 2008 and manually searched the reference lists of relevant trials and reviews, and all issues of two journals. We contacted the authors of all trials or reviews to ask about unpublished trials. Where necessary, we also contacted authors to confirm methods of allocation used and to clarify results presented. We assessed the eligibility of each trial using pre-defined criteria. Selection criteria: Randomised controlled trials of methods to increase response to postal or electronic questionnaires. Data collection and analysis: We extracted data on the trial participants, the intervention, the number randomised to intervention and comparison groups and allocation concealment. For each strategy, we estimated pooled odds ratios (OR) and 95% confidence intervals (CI) in a random-effects model. We assessed evidence for selection bias using Egger's weighted regression method and Begg's rank correlation test and funnel plot. We assessed heterogeneity among trial odds ratios using a Chi 2 test and the degree of inconsistency between trial results was quantified using the I 2 statistic. Main results: Postal We found 481 eligible trials.The trials evaluated 110 different ways of increasing response to postal questionnaires.We found substantial heterogeneity among trial results in half of the strategies. The odds of response were at least doubled using monetary incentives (odds ratio 1.87; 95% CI 1.73 to 2.04; heterogeneity P < 0.00001, I 2 = 84%), recorded delivery (1.76; 95% CI 1.43 to 2.18; P = 0.0001, I 2 = 71%), a teaser on the envelope - e.g. a comment suggesting to participants that they may benefit if they open it (3.08; 95% CI 1.27 to 7.44) and a more interesting questionnaire topic (2.00; 95% CI 1.32 to 3.04; P = 0.06, I 2 = 80%). The odds of response were substantially higher with pre-notification (1.45; 95% CI 1.29 to 1.63; P < 0.00001, I 2 = 89%), follow-up contact (1.35; 95% CI 1.18 to 1.55; P < 0.00001, I 2 = 76%), unconditional incentives (1.61; 1.36 to 1.89; P < 0.00001, I 2 = 88%), shorter questionnaires (1.64; 95%CI 1.43 to 1.87; P < 0.00001, I 2 = 91%), providing a second copy of the questionnaire at follow up (1.46; 95% CI 1.13 to 1.90; P < 0.00001, I 2 = 82%), mentioning an obligation to respond (1.61; 95% CI 1.16 to 2.22; P = 0.98, I 2 = 0%) and university sponsorship (1.32; 95% CI 1.13 to 1.54; P < 0.00001, I 2 = 83%). The odds of response were also increased with non-monetary incentives (1.15; 95% CI 1.08 to 1.22; P < 0.00001, I 2 = 79%), personalised questionnaires (1.14; 95% CI 1.07 to 1.22; P < 0.00001, I 2 = 63%), use of hand-written addresses (1.25; 95% CI 1.08 to 1.45; P = 0.32, I 2 = 14%), use of stamped return envelopes as opposed to franked return envelopes (1.24; 95% CI 1.14 to 1.35; P < 0.00001, I 2 = 69%), an assurance of confidentiality (1.33; 95% CI 1.24 to 1.42) and first class outward mailing (1.11; 95% CI 1.02 to 1.21; P = 0.78, I 2 = 0%). The odds of response were reduced when the questionnaire included questions of a sensitive nature (0.94; 95% CI 0.88 to 1.00; P = 0.51, I 2 = 0%). Electronic: We found 32 eligible trials. The trials evaluated 27 different ways of increasing response to electronic questionnaires. We found substantial heterogeneity among trial results in half of the strategies. The odds of response were increased by more than a half using non-monetary incentives (1.72; 95% CI 1.09 to 2.72; heterogeneity P < 0.00001, I 2 = 95%), shorter e-questionnaires (1.73; 1.40 to 2.13; P = 0.08, I 2 = 68%), including a statement that others had responded (1.52; 95% CI 1.36 to 1.70), and a more interesting topic (1.85; 95% CI 1.52 to 2.26). The odds of response increased by a third using a lottery with immediate notification of results (1.37; 95% CI 1.13 to 1.65), an offer of survey results (1.36; 95% CI 1.15 to 1.61), and using a white background (1.31; 95% CI 1.10 to 1.56). The odds of response were also increased with personalised e-questionnaires (1.24; 95% CI 1.17 to 1.32; P = 0.07, I 2 = 41%), using a simple header (1.23; 95% CI 1.03 to 1.48), using textual representation of response categories (1.19; 95% CI 1.05 to 1.36), and giving a deadline (1.18; 95% CI 1.03 to 1.34). The odds of response tripled when a picture was included in an e-mail (3.05; 95% CI 1.84 to 5.06; P = 0.27, I 2 = 19%). The odds of response were reduced when "Survey" was mentioned in the e-mail subject line (0.81; 95% CI 0.67 to 0.97; P = 0.33, I 2 = 0%), and when the e-mail included a male signature (0.55; 95% CI 0.38 to 0.80; P = 0.96, I 2 = 0%). Authors' conclusions: Health researchers using postal and electronic questionnaires can increase response using the strategies shown to be effective in this systematic review. Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.


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Couvade is the male experience of pregnancy and couvade syndrome incorporates a range of symptoms suffered by ''pregnant'' men. The aetiology of the couvade syndrome is unknown. Anthropologists, psychiatrists, nurses and sociologists have provided explanations for behaviour changes in ''pregnant'' men in terms of cultural pressure, intrapsychic processes and psychosocial adaptation to a new situation. The adoption of a biological perspective allows us to ask a new question: is there a physiological basis for the couvade syndrome? A fresh research agenda would include measurement of physiological change and a search for causation. Implications for nursing are outlined.

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Prior studies of the comparative performance of greenfields and acquisitions have advanced competing arguments, with some arguing that greenfields should outperform acquisitions because acquisitions are costlier to integrate, and others that acquisitions should outperform greenfields because greenfields suffer from a liability of newness. Moreover, while the costs of integration and the liability of newness are at their greatest during a subsidiary's first years, prior studies have tested their competing arguments on samples containing older subsidiaries. We extend these prior studies by (1) developing an institutional theory-based framework that simultaneously considers the costs of integration and the liability of newness, (2) recognizing that both types of costs vary with the level of subsidiary integration, and (3) focusing on the stage of their life during which subsidiaries predominantly incur these costs. To measure subsidiary performance, we ask managers of Dutch multinationals how their ex ante performance expectations compare to the subsidiary's ex post performance during its first two years. Analysing a sample of 191 foreign subsidiaries and controlling for entry mode self-selection and other factors, we find that acquisitions outperform greenfields at low and intermediate levels of subsidiary integration, but that greenfields outperform acquisitions at higher integration levels. [ABSTRACT FROM AUTHOR]

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The Crowned Harp provides a detailed analysis of policing in Northern Ireland. Tracing its history from 1922, Ellison and Smyth portray the Royal Ulster Constabulary (RUC) as an organisation burdened by its past as a colonial police force. They analyse its perceived close relationship with unionism and why, for many nationalists, the RUC embodied the problem of the legitimacy of Northern Ireland, arguing that decisions made on the organisation, composition and ideology of policing in the early years of the state had consequences which went beyond the everyday practice of policing.

The authors provide an extended discussion of policing after the outbreak of civil unrest in 1969, ask why policing was cast in a paramilitary mould, and look at the use of special constabularies and the way in which the police dealt with social unrest which threatened to break down sectarian divisions. Examining the reorganisations of the RUC in the 1970s and 1980s, Ellison and Smyth focus on the various structural, legal and ideological components, the professionalisation of the force and the development of a coherent, if contradictory, ideology. The analysis of the RUC during this period sheds light on the problematic nature of using the police as a counter insurgency force in a divided society. Perceptions of the police, and the opinions of rank and file members are examined and an assessment is made of the various alternative models of policing, such as community policing and local control. This book offers important lessons about the nature of policing in divided societies.

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Many of the most interesting questions ecologists ask lead to analyses of spatial data. Yet, perhaps confused by the large number of statistical models and fitting methods available, many ecologists seem to believe this is best left to specialists. Here, we describe the issues that need consideration when analysing spatial data and illustrate these using simulation studies. Our comparative analysis involves using methods including generalized least squares, spatial filters, wavelet revised models, conditional autoregressive models and generalized additive mixed models to estimate regression coefficients from synthetic but realistic data sets, including some which violate standard regression assumptions. We assess the performance of each method using two measures and using statistical error rates for model selection. Methods that performed well included generalized least squares family of models and a Bayesian implementation of the conditional auto-regressive model. Ordinary least squares also performed adequately in the absence of model selection, but had poorly controlled Type I error rates and so did not show the improvements in performance under model selection when using the above methods. Removing large-scale spatial trends in the response led to poor performance. These are empirical results; hence extrapolation of these findings to other situations should be performed cautiously. Nevertheless, our simulation-based approach provides much stronger evidence for comparative analysis than assessments based on single or small numbers of data sets, and should be considered a necessary foundation for statements of this type in future.

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This article explores the dynamics of the space of exception at the borders of Europe in the Spanish enclave of Melilla, and the neighboring Moroccan city of Oujda. Building upon field research conducted in the spring of 2008, I ask how we can understand the political space of migration not simply as exceptional, but as shaped by the mobility of the irregular migrants moving outside of the frameworks, policies, and practices of the state. By privileging the migrant narrative and making use of Rancière's conception of politics as shaped by the demands of those who “have no part,” I suggest an alternative way of understanding the politics of exception and agency of non-citizens—that is, one of disruption and demands to open up powerful potentials for change in an otherwise rigid regime.

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Strong civil society provides individuals with arenas to bring their interests to the attention of policymakers. In so doing, civil society organizations (CSOs) can support state policies, but can also criticize policies. This paper argues that most minority rights advocacy CSOs in the Baltic states have little say in the crafting of policy and are compartmentalized into the existing agendas, with only a few groups able to evaluate policies independently. It concludes that the Baltic civil society is weak because the CSOs working on minority issues ask policymakers either too much, or too little. The findings suggest that policymakers quell criticism of their work from the side of the CSOs by ignoring their activities. Alternatively, by funding the CSO that shores up the state agenda, policymakers delegate their responsibilities to civic actors, keep critical voices from public debates and claim that their policies have the full support of a vibrant civil society. This paper investigates the options available for civil society actors to relate to policymakers in a nationalizing state by drawing on the data collected in 77 semi-structured interviews with the CSOs working with Russian and Polish minorities in the Baltic states between 2006 and 2009. © 2011 Association for the Study of Nationalities.

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In this paper we seek to show how marketing activities inscribe value on business model innovation, representative of an act, or sequence of socially interconnecting acts. Theoretically we ask two interlinked questions: (1) how can value inscriptions contribute to business model innovations? (2) how can marketing activities support the inscription of value on business model innovations? Semi-structured in-depth interviews were conducted with the thirty-seven members from across four industrial projects commercializing disruptive digital innovations. Various individuals from a diverse range of firms are shown to cast relevant components of their agency and knowledge on business model innovations through negotiation as an ongoing social process. Value inscription is mutually constituted from the marketing activities, interactions and negotiations of multiple project members across firms and functions to counter destabilizing forces and tensions arising from the commercialization of disruptive digital innovations. This contributes to recent conceptual thinking in the industrial marketing literature, which views business models as situated within dynamic business networks and a context-led evolutionary process. A contribution is also made to debate in the marketing literature around marketing's boundary-spanning role, with marketing activities shown to span and navigate across functions and firms in supporting value inscriptions on business model innovations.