14 resultados para (galaxy): open clusters and associations : individual : DBSB 48 and Trumpler 14
em Aston University Research Archive
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Self-sustained spin clusters are analytically linked to ergodicity breaking in fully connected Ising and Sherrington-Kirkpatick (SK) models, relating the less understood spin space to the well understood state space. This correspondence is established through the absence of clusters in the paramagnetic phase, the presence of one dominant cluster in the Ising ferromagnet, and the formation of nontrivial clusters in SK spin glass. Yet unobserved phenomena are also revealed such as a first order phase transition in cluster sizes in the SK ferromagnet. The method could be adapted to investigate other spin models. © 2013 American Physical Society.
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The undisputed link of the agricultural sector with regional economies, along with the increased competition, fosters agri-business companies to rethink their business philosophy and to transform from isolated firms to members of more extended business formations. The paper examines a particular type of business network, the cluster. It focuses on the concept of clusters and on cluster-based strategies in the context of agriculture. In particular, the paper explores the value of clusters by taking into consideration the particularities of the agricultural sector. Potential benefits and constraints of agri-business cluster development are also presented.
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The normative migration rights literature has engaged with the situated experience of migration to a very limited extent, with particularly little attention paid to non-migrants living in receiving localities. This article argues that exploring the non-elite narratives of non-migrants provides valuable insights for normative theorising about migration rights. The discussion is illustrated with a description of research undertaken within rural migration-receiving communities in England, which shows how the narratives of non-migrants shape the experience of migration at a micro-level. This article discusses the implications of this research for normative theory in order to demonstrate the value of this methodological approach.
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Overlaying maps using a desktop GIS is often the first step of a multivariate spatial analysis. The potential of this operation has increased considerably as data sources and Web services to manipulate them are becoming widely available via the Internet. Standards from the OGC enable such geospatial mashups to be seamless and user driven, involving discovery of thematic data. The user is naturally inclined to look for spatial clusters and correlation of outcomes. Using classical cluster detection scan methods to identify multivariate associations can be problematic in this context, because of a lack of control on or knowledge about background populations. For public health and epidemiological mapping, this limiting factor can be critical but often the focus is on spatial identification of risk factors associated with health or clinical status. Spatial entropy index HSu for the ScankOO analysis of the hypothetical dataset using a vicinity which is fixed by the number of points without distinction between their labels. (The size of the labels is proportional to the inverse of the index) In this article we point out that this association itself can ensure some control on underlying populations, and develop an exploratory scan statistic framework for multivariate associations. Inference using statistical map methodologies can be used to test the clustered associations. The approach is illustrated with a hypothetical data example and an epidemiological study on community MRSA. Scenarios of potential use for online mashups are introduced but full implementation is left for further research.
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The attention of linguists has increasingly shifted from grammar to lexis. Collocation has emerged as a key feature of lexis. Research using large language corpora has not only helped to identify the significant collocates of individual words but also to confirm the importance of collocation in the language system. John Sinclair has suggested that language operates on two principles: open choice and idiom. If so, then collocation would appear to be the minimal level of idiomaticity. One problem with collocation is that words that habitually co-occur form less distinct, often discontinuous, idiomatic units, whereas grammar generally works with more precisely delineated and contiguous structural units. This paper uses examples from corpus evidence to look at various aspects of collocation.
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Investigations of relationships between the specific personality variable, locus of control (LOC, Rotter, 1966) and driver behaviour or accidents have returned contrasting results. Review suggests dependence on gender or experience characteristics of participants, suggesting these factors interact with LOC to influence driving. Relationships were investigated in terms of influence on the eight driving styles of the Multidimensional Driving Style Inventory (MDSI, Taubman-Ben-Ari, Mikulincer & Gillarth, 2004) in young drivers (18-29 years). Gender and LOC differences in driving styles previously related to accidents were proposed. It was also proposed that driving experience influences driving style, and LOC influences effect of driving experience. Gender differences were found for dissociative, anxious, patient, risky, angry and high velocity styles. Women had more external LOC than men, and driver stress styles increased with more external LOC, but reduced with increased driving experience, but so did patient style. High velocity style increased with experience. Controlling for LOC revealed important gender differences in effect of experience: positive effects for men (reducing angry and high velocity, increasing carefulness) and negative effects for women (increasing angry and higher velocity, reducing carefulness). Findings suggest negative influence of high internal LOC on young men in terms of its interaction with experience.
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Overlaying maps using a desktop GIS is often the first step of a multivariate spatial analysis. The potential of this operation has increased considerably as data sources an dWeb services to manipulate them are becoming widely available via the Internet. Standards from the OGC enable such geospatial ‘mashups’ to be seamless and user driven, involving discovery of thematic data. The user is naturally inclined to look for spatial clusters and ‘correlation’ of outcomes. Using classical cluster detection scan methods to identify multivariate associations can be problematic in this context, because of a lack of control on or knowledge about background populations. For public health and epidemiological mapping, this limiting factor can be critical but often the focus is on spatial identification of risk factors associated with health or clinical status. In this article we point out that this association itself can ensure some control on underlying populations, and develop an exploratory scan statistic framework for multivariate associations. Inference using statistical map methodologies can be used to test the clustered associations. The approach is illustrated with a hypothetical data example and an epidemiological study on community MRSA. Scenarios of potential use for online mashups are introduced but full implementation is left for further research.
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An increasing number of organisational researchers have turned to social capital theory in an attempt to better understand the impetus for knowledge sharing at the individual and organisational level. This thesis extends that research by investigating the impact of social capital on knowledge sharing at the group-level in the organisational project context. The objective of the thesis is to investigate the importance of social capital in fostering tacit knowledge sharing among the team members of a project. The analytical focus is on the Nahapiet and Ghoshal framework of social capital but also includes elements of other scholars' work. In brief, social capital is defined as an asset that is embedded in the network of relationships possessed by an individual or social unit. It is argued that the main dimensions of social capital that are of relevance to knowledge sharing are structural, cognitive, and relational because these, among other things, foster the exchange and combination of knowledge and resources among the team members. Empirically, the study is based on the grounded theory method. Data were collected from five projects in large, medium, and small ICT companies in Malaysia. Underpinned by the constant comparative method, data were derived from 55 interviews, and observations. The data were analysed using open, axial, and selective coding. The analysis also involved counting frequency occurrence from the coding generated by grounded theory to find the important items and categories under social capital dimensions and knowledge sharing, and for further explaining sub-groups within the data. The analysis shows that the most important dimension for tacit knowledge sharing is structural capital. Most importantly, the findings also suggest that structural capital is a prerequisite of cognitive capital and relational capital at the group-level in an organisational project. It also found that in a project context, relational capital is hard to realise because it requires time and frequent interactions among the team members. The findings from quantitative analysis show that frequent meetings and interactions, relationship, positions, shared visions, shared objectives, and collaboration are among the factors that foster the sharing of tacit knowledge among the team members. In conclusion, the present study adds to the existing literature on social capital in two main ways. Firstly, it distinguishes the dimensions of social capital and identifies that structural capital is the most important dimension in social capital and it is a prerequisite of cognitive and relational capital in a project context. Secondly, it identifies the causal sequence in the dimension of social capital suggesting avenues for further theoretical and empirical work in this emerging area of inquiry.
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In the UK, Open Learning has been used in industrial training for at least the last decade. Trainers and Open Learning practitioners have been concerned about the quality of the products and services being delivered. The argument put forward in this thesis is that there is ambiguity amongst industrialists over the meanings of `Open Learning' and `Quality in Open Learning'. For clarity, a new definition of Open Learning is proposed which challenges the traditional learner-centred approach favoured by educationalists. It introduces the concept that there are benefits afforded to the trainer/employer/teacher as well as to the learner. This enables a focussed view of what quality in Open Learning really means. Having discussed these issues, a new quantitative method of evaluating Open Learning is proposed. This is based upon an assessment of the degree of compliance with which products meet Parts 1 & 2 of the Open Learning Code of Practice. The vehicle for these research studies has been a commercial contract commissioned by the Training Agency for the Engineering Industry Training Board (EITB) to examine the quality of Open Learning products supplied to the engineering industry. A major part of this research has been the application of the evaluation technique to a range of 67 Open Learning products (in eight subject areas). The findings were that good quality products can be found right across the price range - so can average and poor quality ones. The study also shows quite convincingly that there are good quality products to be found at less than 50. Finally the majority (24 out of 34) of the good quality products were text based.
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In Alzheimer's disease (AD), the 'Cascade hypothesis' proposes that the formation of paired helical filaments (PHF) may be casually linked to the deposition of beta/A4 protein. Hence, there should be a close spatial relationship between senile plaques and cellular neurofibrillary tangles in a local region of the brain. In tissue from 6 AD patients, plaques and tangles occurred in clusters and individual clusters were often regularly spaced along the cortical strip. However, the clusters of plaques and tangles were in phase in only 4/32 cortical tissues examined. Hence, the data were not consistent with the 'Cascade hypothesis' that beta/A4 and PHF are directly linked in AD.
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Internally heated fluids are found across the nuclear fuel cycle. In certain situations the motion of the fluid is driven by the decay heat (i.e. corium melt pools in severe accidents, the shutdown of liquid metal reactors, molten salt and the passive control of light water reactors) as well as normal operation (i.e. intermediate waste storage and generation IV reactor designs). This can in the long-term affect reactor vessel integrity or lead to localized hot spots and accumulation of solid wastes that may prompt local increases in activity. Two approaches to the modeling of internally heated convection are presented here. These are based on numerical analysis using codes developed in-house and simulations using widely available computational fluid dynamics solvers. Open and closed fluid layers at around the transition between conduction and convection of various aspect ratios are considered. We determine optimum domain aspect ratio (1:7:7 up to 1:24:24 for open systems and 5:5:1, 1:10:10 and 1:20:20 for closed systems), mesh resolutions and turbulence models required to accurately and efficiently capture the convection structures that evolve when perturbing the conductive state of the fluid layer. Note that the open and closed fluid layers we study here are bounded by a conducting surface over an insulating surface. Conclusions will be drawn on the influence of the periodic boundary conditions on the flow patterns observed. We have also examined the stability of the nonlinear solutions that we found with the aim of identifying the bifurcation sequence of these solutions en route to turbulence.
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This paper explores the links between open innovation and the emergence of a ‘phoenix industry’ centred on the UK’s traditional automotive heartland, the West Midlands, which has developed a significant presence in automotive design and engineering, particularly among small and niche firms. Drawing on case study research, the paper investigates whether this can be considered as a phoenix industry, and to what extent open innovation has been important in the industry’s development. The paper considers relationships between firms and impacts in terms of changing economic and labour market conditions. The paper concludes by examining the role that public policy has played to date and might play in the future in supporting an emerging phoenix industry with open innovation features.