37 resultados para Minimum spanning forests

em Queensland University of Technology - ePrints Archive


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Background Bactrocera dorsalis s.s. is a pestiferous tephritid fruit fly distributed from Pakistan to the Pacific, with the Thai/Malay peninsula its southern limit. Sister pest taxa, B. papayae and B. philippinensis, occur in the southeast Asian archipelago and the Philippines, respectively. The relationship among these species is unclear due to their high molecular and morphological similarity. This study analysed population structure of these three species within a southeast Asian biogeographical context to assess potential dispersal patterns and the validity of their current taxonomic status. Results Geometric morphometric results generated from 15 landmarks for wings of 169 flies revealed significant differences in wing shape between almost all sites following canonical variate analysis. For the combined data set there was a greater isolation-by-distance (IBD) effect under a ‘non-Euclidean’ scenario which used geographical distances within a biogeographical ‘Sundaland context’ (r2 = 0.772, P < 0.0001) as compared to a ‘Euclidean’ scenario for which direct geographic distances between sample sites was used (r2 = 0.217, P < 0.01). COI sequence data were obtained for 156 individuals and yielded 83 unique haplotypes with no correlation to current taxonomic designations via a minimum spanning network. BEAST analysis provided a root age and location of 540kya in northern Thailand, with migration of B. dorsalis s.l. into Malaysia 470kya and Sumatra 270kya. Two migration events into the Philippines are inferred. Sequence data revealed a weak but significant IBD effect under the ‘non-Euclidean’ scenario (r2 = 0.110, P < 0.05), with no historical migration evident between Taiwan and the Philippines. Results are consistent with those expected at the intra-specific level. Conclusions Bactrocera dorsalis s.s., B. papayae and B. philippinensis likely represent one species structured around the South China Sea, having migrated from northern Thailand into the southeast Asian archipelago and across into the Philippines. No migration is apparent between the Philippines and Taiwan. This information has implications for quarantine, trade and pest management.

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Fair Work Australia is to provide the institutional framework for the Australian industrial relations system from January 2010. Its creation provides the opportunity to improve minimum labour standards’ enforcement in Australia. However, the experience of the past must be appreciated and traditional assumptions about the operation of the Australian enforcement system discarded if the new institution is to be effective in its role. This paper focuses on the role of unions in enforcement as well as institutional location issues to expose a number of central enforcement problems that those seeking to establish new systems and processes should consider. A number of recommendations in respect of the structure of Fair Work Australia and the continuing role of unions are suggested.

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We present a new penalty-based genetic algorithm for the multi-source and multi-sink minimum vertex cut problem, and illustrate the algorithm’s usefulness with two real-world applications. It is proved in this paper that the genetic algorithm always produces a feasible solution by exploiting some domain-specific knowledge. The genetic algorithm has been implemented on the example applications and evaluated to show how well it scales as the problem size increases.

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Appropriate behaviours toward customers often requires employees to suppress some genuine emotions and/or express other emotions; genuine or contrived. Managing one's emotions in this way gives rise to emotional exhaustion. This can have consequences for psychological ill health, in the form of work place strain, and ultimately employee's desire to leave. This student examines the relationships between emotional management, emotional exhaustion and turnover intentions amongst diversional therapy professionals. We find that some forms of emotional management have a significant impact on emotional exhaustion and that this predicts workplace strain. Furthermore, the deleterious effects of emotional exhaustion are mitigated somewhat for employees who have strong beliefs in their ability to provide good service, compared to employees with lower self efficacy beliefs.

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In this paper, we present a finite sample analysis of the sample minimum-variance frontier under the assumption that the returns are independent and multivariate normally distributed. We show that the sample minimum-variance frontier is a highly biased estimator of the population frontier, and we propose an improved estimator of the population frontier. In addition, we provide the exact distribution of the out-of-sample mean and variance of sample minimum-variance portfolios. This allows us to understand the impact of estimation error on the performance of in-sample optimal portfolios. Key Words: minimum-variance frontier; efficiency set constants; finite sample distribution

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Background The preservation of meniscal tissue is important to protect joint surfaces. Purpose We have an aggressive approach to meniscal repair, including repairing tears other than those classically suited to repair. Here we present the medium- to long-term outcome of meniscal repair (inside-out) in elite athletes. Study Design Case series; Level of evidence, 4. Methods Forty-two elite athletes underwent 45 meniscal repairs. All repairs were performed using an arthroscopically assisted inside-out technique. Eighty-three percent of these athletes had ACL reconstruction at the same time. Patients returned a completed questionnaire (including Lysholm and International Knee Documentation Committee [IKDC] scores). Mean follow-up was 8.5 years. Failure was defined by patients developing symptoms of joint line pain and/or locking or swelling requiring repeat arthroscopy and partial meniscectomy. Results The average Lysholm and subjective IKDC scores were 89.6 and 85.4, respectively. Eighty-one percent of patients returned to their main sport and most to a similar level at a mean time of 10.4 months after repair, reflecting the high level of ACL reconstruction in this group. We identified 11 definite failures, 10 medial and 1 lateral meniscus, that required excision; this represents a 24% failure rate. We identified 1 further patient who had possible failed repairs, giving a worst-case failure rate of 26.7% at a mean of 42 months after surgery. However, 7 of these failures were associated with a further injury. Therefore, the atraumatic failure rate was 11%. Age and size and location of the tears were not associated with a higher failure rate. Medial meniscal repairs were significantly more likely to fail than lateral meniscal repairs, with a failure rate of 36.4% and 5.6%, respectively (P < .05). Conclusion Meniscal repair and healing are possible, and most elite athletes can return to their preinjury level of activity.

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This thesis articulates a methodology that can be applied to the analysis and design of underlying organisational structures and processes that will consistently and effectively address ‘wicked problems’ (the most difficult class of problems that we can conceptualise: problems which consist of ‘clusters’ of problems; problems within these clusters cannot be solved in isolation from one another, and include sociopolitical and moral-spiritual issues (Rittel and Webber 1973)) in forestry. This transdisciplinary methodology has been developed from the perspective of institutional economics synthesised with perspectives from ecological economics and system dynamics. The institutionalist policymaking framework provides an approach for the explicit development of holistic policy. An illustrative application of this framework has been applied to the wicked problem of forestry in southern Tasmania as an example of the applicability of the approach in the Australian context. To date all attempts to seek solutions to that prevailing wicked problem set have relied on non-reflexive, partial and highly reductionist thinking. A formal assessment of prevailing governance and process arrangements applying to that particular forestry industry has been undertaken using the social fabric matrix. This methodology lies at the heart of the institutionalist policymaking framework, and allows for the systematic exploration of elaborately complex causal links and relationships, such as are present in southern Tasmania. Some possible attributes of an alternative approach to forest management that sustains ecological, social and economic values of forests have been articulated as indicative of the alternative policy and management outcomes that real-world application of this transdisciplinary, discursive and reflexive framework may crystallise. Substantive and lasting solutions to wicked problems need to be formed endogenously, that is, from within the system. The institutionalist policymaking framework is a vehicle through which this endogenous creation of solutions to wicked problems may be realised.

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Among the many factors that influence enforcement agencies, this article examines the role of the institutional location (and independence) of agencies, and an incumbent government's ideology. It is argued that institutional location affects the level of political influence on the agency's operations, while government ideology affects its willingness to resource enforcement agencies and approve regulatory activities. Evidence from the agency regulating minimum labour standards in the Australian federal industrial relations jurisdiction (currently the Fair Work Ombudsman) highlights two divergences from the regulatory enforcement literature generally. First, notions of independence from political interference offered by institutional location are more illusory than real and, second, political need motivates political action to a greater extent than political ideology.

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The complex transition from convict to free labour influenced state intervention in the employment relationship, and initiated the first minimum labour standards in Australia in 1828. Since then, two principal sets of tensions have affected the enforcement of such standards: tensions between government and employers, and tensions between the major political parties over industrial and economic issues. This article argues that these tensions have resulted in a sustained legacy affecting minimum labour standards’ enforcement in Australia. The article outlines broad historical developments and contexts of minimum labour standards’ enforcement in Australia since 1828, with more contemporary exploration focusing specifically on enforcement practices and policies in the Australian federal industrial relations jurisdiction. Current enforcement practices are an outcome of this volatile history, and past influences remain strong.

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Boundary spanning links organisations to one another in order to create mutually beneficial relationships; it is a concept developed and used in organisational theory but rarely used to understand organisational structures in higher education (Pruitt & Schwartz, 1999). Yet understanding boundary spanning activity has the capacity to help universities respond to demands for continuous quality improvement, and to increase capacity to react to environmental uncertainty. At a time of rapid change characterised by a fluctuating economic environment, globalisation, increased mobility, and ecological issues, boundary spanning could be viewed as a key element in assisting institutions in effectively understanding and responding to such change. The literature suggests that effective boundary spanning could help universities improve organisational performance, use of infrastructure and resources, intergroup relations, leadership styles, performance and levels of job satisfaction, technology transfer, knowledge creation, and feedback processes, amongst other things. Our research aims to put a face on boundary spanning (Miller, 2008) by contextualising it within organisational systems and structures in university departments responsible for work related programs i.e. Work Integrated Learning (WIL) and Co-operative Education (Co-op). In this paper these approaches are referred to collectively as work related programs. The authors formed a research team in Victoria, British Columbia in 2009 at a sponsored international research forum, Two Days in June. The purpose of the invitation-only forum was to investigate commonalities and differences across programs and to formulate an international research agenda for work related programs over the next five to ten years. Researchers from Queensland University of Technology, University of Cincinnati, Baden-Wuerttemberg Cooperative State University, University of Ottawa,and Dublin City University agreed that further research was needed into the impact stakeholders, organisational systems, structures, policies, and practices have on departments delivering work related programs. This paper illustrates how policy and practice across the five institutions can be better understood through the lens of boundary spanning. It is argued that boundary spanning is an area of theory and practice with great applicability to a better understanding of the activity of these departments. The paper concludes by proposing topics for future research to examine how boundary spanning can be used to better understand practice and change in work related programs.

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Regulatory commentators have identified the need for more responsive regulation to allow enforcement agencies to respond to different types and degrees of non-compliance. One tool considered to support responsive enforcement is the Enforceable Undertaking (EU). EUs are used extensively by Australian regulators in decisions that forego litigation in exchange for offenders promising to (amongst other things) correct behaviour and comply in the future. This arguably allows regulatory agencies greater flexibility in how they obtain compliance with regulations. EUs became an additional enforcement tool for the Fair Work Ombudsman (FWO) under the Fair Work Act 2009. This paper is a preliminary exploration of the comparative use of EUs by the Australian Competition and Consumer Commission and the FWO to assess their effectiveness for the minimum labour standards' environment.