941 resultados para Non-commutative Landau problem


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Introduction: Chronic disease is a major public health burden on Australian society. An increasing proportion of the population has risk factors for, or at least one, chronic disease, leading to increasing public health costs. Health service policy and delivery must not only address acute conditions, it must also effectively respond to the wide range of health and public service requirements of people with chronic illness.1,2 Strong primary health care policy is an important foundation for a successful national health delivery system and long term management of public health, and is linked to practical outcomes including lower mortality, decreased hospitalisation and improved health outcomes.1 National strategic health policy has recently given increased recognition to the importance of chronic disease management, with the Australian Federal Government endorsement of a number of initiatives for the prevention (or delay in onset), early detection and evidence based management of chronic disease, including osteoarthritis.1,3
Chronic musculoskeletal conditions, including arthritis, account for over 4% of the national disease burden in terms of disability adjusted life years. Over 6 million Australians (almost one-third of the population) are estimated to have a chronic musculoskeletal disease; chronic musculoskeletal disease represents the main cause of long term pain and physical disability. In Australia, osteoarthritis is self reported by more than 1.4 million people (7.3% of the population4) and is the tenth most commonly managed problem in general practice.5 This number is set to rise as the elderly population grows. Osteoarthritis exerts a significant burden on the individual and the community through reduction in quality of life, diminished employment capacity and an increase in health care costs. For further details, refer to the Evidence to support the National Action Plan for Osteoarthritis, Rheumatoid Arthritis and Osteoporosis: Opportunities to improve health-related quality of life and reduce the burden of disease and disability (2004).6
As such, federal government health policy has identified arthritis as a National Health Priority Area and adopted a number of initiatives aimed at decreasing the burden of chronic disease and disability; raising awareness of preventive disease factors; providing access to evidence based knowledge; and improving the overall management of arthritis within the community.4 In 2002, all Australian health ministers designated arthritis and musculoskeletal conditions as Australia’s seventh National Health Priority Area. In response, a National Action Plan was developed in 2004 by the National Arthritis and Musculoskeletal Conditions Advisory Group (NAMSCAG).6 The aim of this document was to provide a blueprint for national initiatives to improve the health related quality of life of people living with osteoarthritis, rheumatoid arthritis and osteoporosis; reduce the cost and prevalence of these conditions; and reduce the impact on individuals, their carers and their communities within Australia. The National Action Plan was developed to complement both the National Chronic Disease Strategy – which is broader – and the National Service Improvement Framework for Osteoarthritis, Rheumatoid Arthritis and Osteoporosis, in addition to other national and state/ territory structures.

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Hard determinism, in theological dress, holds that there is no human free will since God is the sufficient active cause of everything that happens in creation. It is surprising that, in the ever-growing literature on the problem of evil, very little attention has been paid to theodicies that adopt a hard determinist outlook. It is commonly assumed that without free will the theodical project is a non-starter. I challenge this long-held assumption by, firstly, developing a cumulative-style theodicy from within a hard determinist framework, and secondly, comparing the merits of such a theodicy with two libertarian rivals, specifically, Molinism and open theism. The hard determinist model of divine providence is, I argue, in no worse shape than the principal models developed by libertarians.

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Theodicy, the enterprise of searching for greater goods that might plausibly justify God’s permission of evil, is often criticized on the grounds that the project has systematically failed to unearth any such goods. But theodicists also face a deeper challenge, one that places under question the very attempt to look for any morally sufficient reasons God might have for creating a world littered with evil. This ‘anti-theodical’ view argues that theists (and non-theists) ought to reject, primarily for moral reasons, the project of ‘justifying the ways of God to men’. Unfortunately, this view has not received the serious attention it deserves, particularly in analytic philosophy of religion. Taking my cues from such anti-theodicists as Kenneth Surin, D.Z. Phillips and Dostoyevsky’s Ivan Karamazov, I defend several reasons for holding that the way of thinking about God and evil enshrined in theodical discourse can only add to the world’s evils, not remove or illuminate them.

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The study investigated the self-concepts and possible selves of pathological gamblers. Six female egm users were recruited from a Victorian problem gambling counselling service. Three participants were currently gambling and three were not gambling. They were interviewed in-depth and using thematic analysis four dominant themes were identified. (1) Self-concepts tended to be consistent across all participants, (2) having a past self as being the dominant characteristics of possible selves coincided with greater possible selves clarity, (3) non-gambler’s had more elaborate and specific plans for how to create change than did gambler’s, and (4) non-gambler’s had more plans to become possible selves which address goals of intrinsic meaning, rather then having a general goal to ‘not gamble’. The findings are discussed in terms of implications for the cognitive theory of possible selves and suggestions for further research to investigate the utility of the constructs as a basis for a treatment modality.

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The development and use of cocycles for analysis of non-autonomous behaviour is a technique that has been known for several years. Initially developed as an extension to semi-group theory for studying rion-autonornous behaviour, it was extensively used in analysing random dynamical systems [2, 9, 10, 12]. Many of the results regarding asymptotic behaviour developed for random dynamical systems, including the concept of cocycle attractors were successfully transferred and reinterpreted for deterministic non-autonomous systems primarily by P. Kloeden and B. Schmalfuss [20, 21, 28, 29]. The theory concerning cocycle attractors was later developed in various contexts specific to particular classes of dynamical systems [6, 7, 13], although a comprehensive understanding of cocycle attractors (redefined as pullback attractors within this thesis) and their role in the stability of non-autonomous dynamical systems was still at this stage incomplete. It was this purpose that motivated Chapters 1-3 to define and formalise the concept of stability within non-autonomous dynamical systems. The approach taken incorporates the elements of classical asymptotic theory, and refines the notion of pullback attraction with further development towards a study of pull-back stability arid pullback asymptotic stability. In a comprehensive manner, it clearly establishes both pullback and forward (classical) stability theory as fundamentally unique and essential components of non-autonomous stability. Many of the introductory theorems and examples highlight the key properties arid differences between pullback and forward stability. The theory also cohesively retains all the properties of classical asymptotic stability theory in an autonomous environment. These chapters are intended as a fundamental framework from which further research in the various fields of non-autonomous dynamical systems may be extended. A preliminary version of a Lyapunov-like theory that characterises pullback attraction is created as a tool for examining non-autonomous behaviour in Chapter 5. The nature of its usefulness however is at this stage restricted to the converse theorem of asymptotic stability. Chapter 7 introduces the theory of Loci Dynamics. A transformation is made to an alternative dynamical system where forward asymptotic (classical asymptotic) behaviour characterises pullback attraction to a particular point in the original dynamical system. This has the advantage in that certain conventional techniques for a forward analysis may be applied. The remainder of the thesis, Chapters 4, 6 and Section 7.3, investigates the effects of perturbations and discretisations on non-autonomous dynamical systems known to possess structures that exhibit some form of stability or attraction. Chapter 4 investigates autonomous systems with semi-group attractors, that have been non-autonomously perturbed, whilst Chapter 6 observes the effects of discretisation on non-autonomous dynamical systems that exhibit properties of forward asymptotic stability. Chapter 7 explores the same problem of discretisation, but for pullback asymptotically stable systems. The theory of Loci Dynamics is used to analyse the nature of the discretisation, but establishment of results directly analogous to those discovered in Chapter 6 is shown to be unachievable. Instead a case by case analysis is provided for specific classes of dynamical systems, for which the results generate a numerical approximation of the pullback attraction in the original continuous dynamical system. The nature of the results regarding discretisation provide a non-autonomous extension to the work initiated by A. Stuart and J. Humphries [34, 35] for the numerical approximation of semi-group attractors within autonomous systems. . Of particular importance is the effect on the system's asymptotic behaviour over non-finite intervals of discretisation.

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This paper presents a series of numerical simulations dealing with the problem of natural convection flows and associated heat transfer in an enclosure filled with a fluid-saturated porous medium. The analysis is based on the finite element technique and incorporates the Brinkman-extended Darcy model for an oval enclosure. The numerical results obtained for a modified Rayleigh number, Ra, Darcy number, Da, offset, E, and eccentricity, e, are presented and discussed. The numerical predictions for a square enclosure compared well with published data. It is found that any increase in Da or Ra results in a higher fluid velocity that is responsible for shifting the core of the flow. Moreover, at higher ovality (E = 0.5), asymmetric flow is observed even at the lower range of Rayleigh number (Ra ⩽ 20), which may be attributed to the effect of curved isothermal wall.

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Researchers have been endeavoring to discover concise sets of episode rules instead of complete sets in sequences. Existing approaches, however, are not able to process complex sequences and can not guarantee the accuracy of resulting sets due to the violation of anti-monotonicity of the frequency metric. In some real applications, episode rules need to be extracted from complex sequences in which multiple items may appear in a time slot. This paper investigates the discovery of concise episode rules in complex sequences. We define a concise representation called non-derivable episode rules and formularize the mining problem. Adopting a novel anti-monotonic frequency metric, we then develop a fast approach to discover non-derivable episode rules in complex sequences. Experimental results demonstrate that the utility of the proposed approach substantially reduces the number of rules and achieves fast processing.

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We investigate the impact of board independence on earnings management on a sample of family controlled firms listed on the Australian Securities Exchange (ASX). Using panel data over the period 2000–2004, we find evidence of earnings management among family controlled firms in Australia, an environment of high investor protection and private benefits of control. Findings show that a higher proportion of independent directors on boards is effective in reducing earnings management, thereby mitigating agency problems associated with entrenchment and expropriation in family firms. We also find that managers of family firms are less aggressive in managing earnings via discretionary long-term accruals compared to non-family firms.

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This paper proposes an alternative algorithm to solve the median shortest path problem (MSPP) in the planning and design of urban transportation networks. The proposed vector labeling algorithm is based on the labeling of each node in terms of a multiple and conflicting vector of objectives which deletes cyclic, infeasible and extreme-dominated paths in the criteria space imposing cyclic break (CB), path cost constraint (PCC) and access cost parameter (ACP) respectively. The output of the algorithm is a set of Pareto optimal paths (POP) with an objective vector from predetermined origin to destination nodes. Thus, this paper formulates an algorithm to identify a non-inferior solution set of POP based on a non-dominated set of objective vectors that leaves the ultimate decision to decision-makers. A numerical experiment is conducted using an artificial transportation network in order to validate and compare results. Sensitivity analysis has shown that the proposed algorithm is more efficient and advantageous over existing solutions in terms of computing execution time and memory space used.

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Robust regression in statistics leads to challenging optimization problems. Here, we study one such problem, in which the objective is non-smooth, non-convex and expensive to calculate. We study the numerical performance of several derivative-free optimization algorithms with the aim of computing robust multivariate estimators. Our experiences demonstrate that the existing algorithms often fail to deliver optimal solutions. We introduce three new methods that use Powell's derivative-free algorithm. The proposed methods are reliable and can be used when processing very large data sets containing outliers.

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This paper concerns the adaptive fast finite-time multiple-surface sliding control (AFFTMSSC) problem for a class of high-order uncertain non-linear systems of which the upper bounds of the system uncertainties are unknown. By using the fast control Lyapunov function and the method of so-called adding a power integrator merging with adaptive technique, a recursive design procedure is provided, which guarantees the fast finite-time stability of the closed-loop system. Further, it is proved that the control input is bounded.

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This paper proposes an efficient solution algorithm for realistic multi-objective median shortest path problems in the design of urban transportation networks. The proposed problem formulation and solution algorithm to median shortest path problem is based on three realistic objectives via route cost or investment cost, overall travel time of the entire network and total toll revenue. The proposed solution approach to the problem is based on the heuristic labeling and exhaustive search technique in criteria space and solution space of the algorithm respectively. The first labels each node in terms of route cost and deletes cyclic and infeasible paths in criteria space imposing cyclic break and route cost constraint respectively. The latter deletes dominated paths in terms of objectives vector in solution space in order to identify a set of Pareto optimal paths. The approach, thus, proposes a non-inferior solution set of Pareto optimal paths based on non-dominated objective vector and leaves the ultimate decision to decision-makers for purpose specific final decision during applications. A numerical experiment is conducted to test the proposed algorithm using artificial transportation network. Sensitivity analyses have shown that the proposed algorithm is advantageous and efficient over existing algorithms to find a set of Pareto optimal paths to median shortest paths problems.

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Food and non-alcoholic beverage marketing is recognized as an important factor influencing food choices related to non-communicable diseases. The monitoring of populations' exposure to food and non-alcoholic beverage promotions, and the content of these promotions, is necessary to generate evidence to understand the extent of the problem, and to determine appropriate and effective policy responses. A review of studies measuring the nature and extent of exposure to food promotions was conducted to identify approaches to monitoring food promotions via dominant media platforms. A step-wise approach, comprising ‘minimal’, ‘expanded’ and ‘optimal’ monitoring activities, was designed. This approach can be used to assess the frequency and level of exposure of population groups (especially children) to food promotions, the persuasive power of techniques used in promotional communications (power of promotions) and the nutritional composition of promoted food products. Detailed procedures for data sampling, data collection and data analysis for a range of media types are presented, as well as quantifiable measurement indicators for assessing exposure to and power of food and non-alcoholic beverage promotions. The proposed framework supports the development of a consistent system for monitoring food and non-alcoholic beverage promotions for comparison between countries and over time.

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Impulsivity is considered a core feature of problem gambling, however, self-reported impulsivity and inhibitory control may reflect disparate constructs. We examined self-reported impulsivity and inhibitory control in 39 treatment-seeking problem gamblers and 41 matched controls using a range of self-report questionnaires and laboratory inhibitory control tasks. We also investigated differences between treatment-seeking problem gamblers who prefer strategic (e.g., sports-betting) and non-strategic (e.g., electronic gaming machines) gambling activities. Treatment-seeking problem gamblers demonstrated elevated self-reported impulsivity, more go errors on the Stop Signal Task and a lower gap score on the Random Number Generation task than matched controls. However, overall we did not find strong evidence that treatment-seeking problem gamblers are more impulsive on laboratory inhibitory control measures. Furthermore, strategic and non-strategic problem gamblers did not differ from their respective controls on either self-reported impulsivity questionnaires or laboratory inhibitory control measures. Contrary to expectations, our results suggest that inhibitory dyscontrol may not be a key component for some treatment-seeking problem gamblers.

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How to learn an over complete dictionary for sparse representations of image is an important topic in machine learning, sparse coding, blind source separation, etc. The so-called K-singular value decomposition (K-SVD) method [3] is powerful for this purpose, however, it is too time-consuming to apply. Recently, an adaptive orthogonal sparsifying transform (AOST) method has been developed to learn the dictionary that is faster. However, the corresponding coefficient matrix may not be as sparse as that of K-SVD. For solving this problem, in this paper, a non-orthogonal iterative match method is proposed to learn the dictionary. By using the approach of sequentially extracting columns of the stacked image blocks, the non-orthogonal atoms of the dictionary are learned adaptively, and the resultant coefficient matrix is sparser. Experiment results show that the proposed method can yield effective dictionaries and the resulting image representation is sparser than AOST.