766 resultados para Empirical Evidence


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Use of structuring mechanisms (such as modularisation) is widely believed to be one of the key ways to improve software quality. Structuring is considered to be at least as important for specification documents as for source code, since it is assumed to improve comprehensibility. Yet, as with most widely held assumptions in software engineering, there is little empirical evidence to support this hypothesis. Also, even if structuring can be shown to he a good thing, we do not know how much structuring is somehow optimal. One of the more popular formal specification languages, Z, encourages structuring through its schema calculus. A controlled experiment is described in which two hypotheses about the effects of structure on the comprehensibility of Z specifications are tested. Evidence was found that structuring a specification into schemas of about 20 lines long significantly improved comprehensibility over a monolithic specification. However, there seems to be no perceived advantage in breaking down the schemas into much smaller components. The experiment can he fully replicated.

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Objectives: To evaluate the empirical evidence linking nursing resources to patient outcomes in intensive care settings as a framework for future research in this area. Background: Concerns about patient safely and the quality of care are driving research on the clinical and cost-effectiveness of health care interventions, including the deployment of human resources. This is particularly important in intensive care where a large proportion of the health care budget is consumed and where nursing staff is the main item of expenditure. Recommendations about staffing levels have been trade but may not be evidence based and may not always be achieved in practice. Methods: We searched systematically for studies of the impact of nursing resources (e.g. nurse-patient ratios, nurses' level of education, training and experience) on patient Outcomes, including mortality and adverse events, in adult intensive care. Abstracts of articles were reviewed and retrieved if they investigated the relationship between nursing resources and patient Outcomes. Characteristics of the studies were tabulated and the quality of the Studies assessed. Results: Of the 15 studies included in this review, two reported it statistical relationship between nursing resources and both mortality and adverse events, one reported ail association to mortality only, seven studies reported that they Could not reject the null hypothesis of no relationship to mortality and 10 studies (out of 10 that tested the hypothesis) reported a relationship to adverse events. The main explanatory mechanisms were the lack of time for nurses to perform preventative measures, or for patient surveillance. The nurses' role in pain control was noted by One author. Studies were mainly observational and retrospective and varied in scope from 1 to 52 units. Recommendations for future research include developing the mechanisms linking nursing resources to patient Outcomes, and designing large multi-centre prospective Studies that link patient's exposure to nursing care oil a shift-by-shift basis over time. (C) 2007 Elsevier Ltd. All rights reserved.

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The article examines the expansion of private water companies since 1989 the withdrawal from developing countries from 2003 onwards, and the economic impact of privatisation. The analysis is set in the context of the historical development of water services in the north and the south, showing that the role of private water companies since the start of the 20th century has been historically limited and exceptional. The impact of water privatisation is considered in relation to the issues of investment, prices, and efficiency, drawing on empirical evidence from the north and developing countries in Asia, Africa and Latin America. Particular attention is given to France and the UK, where private water companies, for different reasons, are most established. The evidence from both north and south shows systematic underinvestment, monopoly pricing, regulatory gaming, and no significant efficiency differences between public and private sector operators. In conclusion, the article identifies institutional policies including fiscal constraints and lending conditionalities as key drivers of privatisation, and questions whether these can sustain privatisation in the water sector where historical experience indicates it is an inappropriate solution.

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Based on empirical evidence, the article looks at the implications of private sector participation (PSP) for the delivery of water supply and sanitation to the urban and peri-urban poor in developing countries, with particular reference to Africa and Latin America. More precisely, the article addresses the impact produced by multinational companies’ (MNCs) strategies, in light of the pursuit of profitability, on the extension of connections to the pipeline network. It does so by questioning the assumptions that greater private sector efficiency and innovation, together with contract design, will enable the sustainable extension of service coverage to low income dwellers. The strategies of the major water MNCs are considered both in relation to the global expansion of their operations and the adjustment of local strategies to commercial considerations. The latter might result in identifying proWtable markets, modifying contractual provisions, attempting to reduce costs and increase income, reducing risks and exiting from non-performing contracts. The evidence reviewed allows for re-assessing the relative roles of the public and private sectors in extending and delivering water services to the poor. First, the most far reaching innovative approaches to extending connections are more likely to come from communities, public authorities and political activity than from MNCs. Secondly, whenever MNCs are liable to exit from non-profitable contracts, the public sector has no other option than to deal with external risks aVecting continuity of provision. Finally, market limitations affecting MNCs’ ability to serve marginal populations and access cheap capital do not apply to well-organised, politically led public sector undertakings

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Drawing on empirical evidence gathered through the PSIRU database, this contribution aims at addressing the potential of public finance to enhance the provision of water supply and sanitation as a public service. It highlights the problems associated with (and the disappointing results obtained from) resort to Private Sector Participation and private finance, both historically and in the last 15-20 years, in developed and developing countries. It also addresses the advantages of using public finance as a more cost-effective and equitable instrument to achieve developmental objectives such as the expansion of service coverage and development of water and sanitation infrastructure. The potential of public operations in maximising developmental impact from the social, economic and environmental points of view is then explored referring to specific examples from a variety of countries and regions. These include the in-house restructuring of public operations to enhance transparency, accountability and effectiveness, as well as the use of Public-Public Partnerships (PUPs) to build capacity. Attention is devoted to the specific financial requirements of expanding sewerage services at global level to achieve MDGs or broader developmental goals. These requirements are revisited in light of a regional breakdown of coverage gaps, available resources and development aid flows. These findings challenge the established view among international and bilateral agencies that expanding sewerage services in developing countries is excessively costly and should be abandoned as a priority because unaffordable. This contribution draws on a number of PSIRU Reports, and particularly the following. - http://www.psiru.org/reports/2008-03-W-sewers.pdf - http://boell-latinoamerica.org/download_es/agua08_privatizacion_LA_2007.pdf - http://boell-latinoamerica.org/download_es/agua08_agua_un_servicio_publico.pdf - http://www.psiru.org/reports/2006-03-W-investment.pdf All PSIRU Reports are accessible at http://www.psiru.org/publicationsindex.asp.

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The paper provides a critical review of the role of liberalisation and competition in the water sector, based on empirical evidence from the UK and internationally. The paper is submitted as evidence to the official reviews of competition in water sector in England and Wales.

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This paper addresses the potential of public water operations in achieving developmental goals such as the Millennium Development Goals, and argues that the public sector has a comparative advantage in developing water services. The global importance of the public sector in urban water supply is examined through a review of current practice in the world's largest cities, including operational presence and distribution and ongoing trends. Empirical evidence shows that, in transition and developing countries, public operators are capable of undergoing successful reform. One explanatory factor is proposed to be the creation through the public sphere of highly interconnected networks among stakeholders. Such accountability networks act as vehicles for the generation and distribution of public knowledge among stakeholders, which in turn inform rational decision making on the reform and management of operations.

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This paper presents the extensive literature survey based both on theoretical rationales for hedging as well as the empirical evidence that support the implications of the theory regarding the arguments for the corporate risk management relevance and its influence on the company’s value. The survey of literature presented in this paper has revealed that there are two chief classes of rationales for corporate decision to hedge - maximisation of shareholder value or maximisation of managers’ private utility. The paper concludes that, the total benefit of hedging is the combination of all these motives and, if the costs of using corporate risk management instruments are less than the benefits provided via the avenues mentioned in this paper, or any other benefit perceived by the market, then risk management is a shareholder-value enhancing activity.

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Digital games constitute a major emerging technology that is expected to enter mainstream educational use within a few years. The highly engaging and motivating character of such games bears great potential to support immersive, meaningful, and situated learning experiences. To seize this potential, meaningful quality and impact measurements are indispensible. Although there is a growing body of evidence on the efficacy of games for learning, evaluation is often poorly designed, incomplete, biased, if not entirely absent. Well-designed evaluations demonstrating the educational effect as well as the return on investment of serious games may foster broader adoption by educational institutions and training providers, and support the development of the serious game industry. The European project RAGE introduces a comprehensive and multi-perspective framework for serious game evaluation, which is presented in this paper.

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Large-scale biogeographical changes in the biodiversity of a key zooplankton group (calanoid copepods) were detected in the north-eastern part of the North Atlantic Ocean and its adjacent seas over the period 1960–1999. These findings provided key empirical evidence for climate change impacts on marine ecosystems at the regional to oceanic scale. Since 1999, global temperatures have continued to rise in the region. Here, we extend the analysis to the period 1958–2005 using all calanoid copepod species assemblages (nine species assemblages based on an analysis including a total of 108 calanoid species or taxa) and show that this phenomenon has been reinforced in all regions. Our study reveals that the biodiversity of calanoid copepods are responding quickly to sea surface temperature (SST) rise by moving geographically northward at a rapid rate up to about 23.16 km yr−1. Our analysis suggests that nearly half of the increase in sea temperature in the northeast Atlantic and adjacent seas is related to global temperature rises (46.35% of the total variance of temperature) while changes in both natural modes of atmospheric and oceanic circulation explain 26.45% of the total variance of temperature. Although some SST isotherms have moved northwards by an average rate of up to 21.75 km yr−1 (e.g. the North Sea), their movement cannot fully quantify all species assemblage shifts. Furthermore, the observed rates of biogeographical movements are far greater than those observed in the terrestrial realm. Here, we discuss the processes that may explain such a discrepancy and suggest that the differences are mainly explained by the fluid nature of the pelagic domain, the life cycle of the zooplankton and the lesser anthropogenic influence (e.g. exploitation, habitat fragmentation) on these organisms. We also hypothesize that despite changes in the path and intensity of the oceanic currents that may modify quickly and greatly pelagic zooplankton species, these organisms may reflect better the current impact of climate warming on ecosystems as terrestrial organisms are likely to significantly lag the current impact of climate change.

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Interest in animal personalities has generated a burgeoning literature on repeatability in individual traits such as boldness or exploration through time or across different contexts. Yet, repeatability can be influenced by the interactive social strategies of individuals, for example, consistent inter-individual variation in aggression is well documented. Previous work has largely focused on the social aspects of repeatability in animal behaviour by testing individuals in dyadic pairings. Under natural conditions, individuals interact in a heterogeneous polyadic network. However, the extent to which there is repeatability of social traits at this higher order network level remains unknown. Here, we provide the first empirical evidence of consistent and repeatable animal social networks. Using a model species of shark, a taxonomic group in which repeatability in behaviour has yet to be described, we repeatedly quantified the social networks of ten independent shark groups across different habitats, testing repeatability in individual network position under changing environments. To understand better the mechanisms behind repeatable social behaviour, we also explored the coupling between individual preferences for specific group sizes and social network position. We quantify repeatability in sharks by demonstrating that despite changes in aggregation measured at the group level, the social network position of individuals is consistent across treatments. Group size preferences were found to influence the social network position of individuals in small groups but less so for larger groups suggesting network structure, and thus, repeatability was driven by social preference over aggregation tendency.

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In the past twenty years an increasing number of Global South nations have vied for the rights to host prestigious and expensive sport mega events. This trend requires significant reflection given the enormous economic costs of these events, which often produce little capital gain for the host nation (Whitson & Horne, 2006). Furthermore, sport mega events are often utilized for their symbolic capital (Belanger, 2009), which sometimes manifests through forcing people from their land for the sake of “beautification” (Davis, 2006). In this project, then, I asked how technologies of power were utilized by FIFA, corporate stakeholders, and the South African government to control people who were marginal to, or impeded the success of, the World Cup in Nelspruit, South Africa. This project consisted of two parts: the first involved constructing a theoretical framework for better understanding power as it operates through sport mega events in general. To this end I employed Marxian notions of the ordering of physical space, Foucauldian conceptions of sovereignty and governmentality, and Agamben’s (1998) state of exception to determine how particular bodies are constituted and controlled through sport mega events. In the second part, I applied this theoretical framework to the events in South Africa to better elucidate how people became displaced and killed because of the 2010 FIFA World Cup. I used South African popular news and documentaries as empirical evidence and conducted a discursive analysis of said news media. Through this coverage it became apparent that the mega event created the conditions in which new forms of rogue sovereign partnerships could arise through a historically and spatially contingent process of capitalism. The rogue sovereigns’ para-juridico-political orders, the discourses and practices of accumulation by dispossession as a tactic and effect of govermentality, and other historical non-capital subjectivities such as racial identity, all contributed to constituting Agamben’s state of exception in which people could be displaced, killed or left to die in the events surrounding the World Cup.

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Debates around the importance of school ethos have gathered pace in recent years. Whilst it is not clear why this concept has become increasingly important in the educational vernacular the marketisation of education seems to have had some effect. As schools are forced to compete they have become concerned to identify and promote their 'Unique Selling Points' as a means of attracting and maintaining a long term 'customer' base. Defining a school in terms of its particular 'ethos' therefore offers a useful means of identifying and encapsulating the particular strengths of the school. It is thus not uncommon for heads to market their schools on the basis of their endorsing a 'liberal ethos' a 'caring ethos' or a 'sporting ethos' (Gardner, 2003).

The purpose of this chapter is to use empirical evidence to explore the meaning of a 'pluralist ethos' or 'integrated ethos', within the integrated school context in Northern Ireland.

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This paper first explores the conflictual discourses employed by government agencies, citizens’ initiatives, and environmental organizations over the construction of a High Voltage Power Station (KYT) for demands of the 2004 Olympic Games, as presented in media reports and movement literature over a period of one year. Having in mind recent criticisms targeting the lack of empirical evidence in Ulrich Beck’s risk theorization, this exploration is of distinct importance. Secondly, it takes into account that both the defensive character of societal action and mistrust to expert authorities have been confirmed as prevalent characteristics of both the Greek and the general risk social context. The paper attempts to re-evaluate and/or complement existing perspectives of societal activism in general and environmental mobilizations in particular within the confines of the Greek social context. As a tentative conclusion, it is suggested that the risk perspective offers a novel prism for the examination of societal activism without confining it to the characteristics of individual national contexts.

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This paper provides algorithms that use an information-theoretic analysis to learn Bayesian network structures from data. Based on our three-phase learning framework, we develop efficient algorithms that can effectively learn Bayesian networks, requiring only polynomial numbers of conditional independence (CI) tests in typical cases. We provide precise conditions that specify when these algorithms are guaranteed to be correct as well as empirical evidence (from real world applications and simulation tests) that demonstrates that these systems work efficiently and reliably in practice.