975 resultados para DEPENDENT QUANTUM PROBLEMS


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Quantum key distribution (QKD) promises secure key agreement by using quantum mechanical systems. We argue that QKD will be an important part of future cryptographic infrastructures. It can provide long-term confidentiality for encrypted information without reliance on computational assumptions. Although QKD still requires authentication to prevent man-in-the-middle attacks, it can make use of either information-theoretically secure symmetric key authentication or computationally secure public key authentication: even when using public key authentication, we argue that QKD still offers stronger security than classical key agreement.

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Human embryonic stem cell research promises to deliver in the future a whole range of therapeutic treatments, but currently governments in different jurisdictions must try to regulate this burgeoning area. Part of the problem has been, and continues to be, polarised community opinion on the use of human embryonic stem cells for research. This article compares the approaches of the Australian, United Kingdom and United States governments in regulating human embryonic stem cell research. To date, these governments have approached the issue through implementing legislation or policy to control research. Similarly, the three jurisdictions have viewed the patentability of human embryonic stem cell technologies in their own ways with different policies being adopted by the three patent offices. This article examines these different approaches and discusses the inevitable concerns that have been raised due to the lack of a universal approach in relation to the regulation of research; the patenting of stem cell technologies; and the effects patents granted are having on further human embryonic stem cell research.

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Although some developmental disabilities may be identified soon after birth (e.g. Down Syndrome) many problems do not become apparent until much later. The first indication of a significant disorder may be the infant's failure to achieve early developmental milestones at the expected ages, but the variability and subtlety of symtoms in many developmental disorders often makes them difficult to recognise. Clearly itis desirable to identify developmental problems as early as possible to ensure the provision of appropriate support and intervention services and to lessen the impact on subsequent development.

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Construction projects are faced with a challenge that must not be underestimated. These projects are increasingly becoming highly competitive, more complex, and difficult to manage. They become ‘wicked problems’, which are difficult to solve using traditional approaches. Soft Systems Methodology (SSM) is a systems approach that is used for analysis and problem solving in such complex and messy situations. SSM uses “systems thinking” in a cycle of action research, learning and reflection to help understand the various perceptions that exist in the minds of the different people involved in the situation. This paper examines the benefits of applying SSM to wicked problems in construction project management, especially those situations that are challenging to understand and difficult to act upon. It includes relevant examples of its use in dealing with the confusing situations that incorporate human, organizational and technical aspects.

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Small and micro-enterprises play a significant part in most economies. However, in developing countries these enterprises have often been planned and implemented from a poverty alleviation perspective, rather than as entrepreneurial activities and growing businesses (Mead & Liedholm 1998, Toye 1993). This paper explores a model for sustainable support to micro-enterprises in a developing country context. Sustainability is critical if micro-enterprises are to grow. The traditional philanthropic model for funding micro-enterprises leaves local communities dependent on the priorities of donors which may not always be consistent with those of the community. Long term sustainability requires a move to a model that broadens the base of both economic and intellectual resources, that builds capacity as well as providing ‘start-up’ funding through mechanism such as micro-credit (Elkington & Hartigan 2008). Designing for sustainable enterprise development includes responding to the community’s priorities, investigating individual problems and solutions, encouraging agency and active involvement in goal setting, with on-going consultation and co-development of solutions. Recognising the importance of experimentation we have moved beyond existing forms to prototype new ways of working which provide continuity of financial and intellectual support for local initiatives. The paper reviews existing micro finance and microcredit practices and suggests a new approach to establish and support enterprises with financial and knowledge resources for sustainable business practices. Principles underlying such a program and the initial steps are described.

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This article attempts to explore the concept of scientific community at the macro-national level in the context of Iran. Institutionalisation of science and its professional growth has been constrained by several factors. The article first conceptualises the notion of science community as found in the literature in the context of Iran, and attempts to map through some indicators. The main focus, however, lies in mapping some institutional problems through empirical research. This was undertaken in 2002–04 in order to analyse the structure of the scientific community in Iran in the ‘exact sciences’ (mathematics, physics, chemistry, biology and earth sciences). The empirical work was done in two complementary perspectives: through a questionnaire and statistical analysis of it, and through semistructured interviews with the researchers. There are number of problems confronting scientists in Iran. Facilities provided by institutions is one of the major problems of research. Another is the tenuous cooperation among scientists. This is reported by most of the researchers, who deplore the lack of cooperation among their group. Relationships are mostly with the Ph.D. students and only marginally with colleagues. Our research shows that the more brilliant the scientists, the more frustrated they are from scientific institutions in Iran. Medium-range researchers seem to be much happier about the scientific institution to which they belong than the brighter scholars. The scientific institutions in Iran seem to be built for the needs of the former rather than the latter. These institutions seem not to play a positive role in the case of the best scientists. On the whole, many ingredients of the scientific community, at least at its inception, are present among Iranian scientists: the strong desire for scientific achievement in spite of personal, institutional and economic problems.

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Healthcare-associated methicillin-resistant Staphylococcus aureus(MRSA) infection may cause increased hospital stay or, sometimes, death. Quantifying this effect is complicated because it is a time-dependent exposure: infection may prolong hospital stay, while longer stays increase the risk of infection. We overcome these problems by using a multinomial longitudinal model for estimating the daily probability of death and discharge. We then extend the basic model to estimate how the effect of MRSA infection varies over time, and to quantify the number of excess ICU days due to infection. We find that infection decreases the relative risk of discharge (relative risk ratio = 0.68, 95% credible interval: 0.54, 0.82), but is only indirectly associated with increased mortality. An infection on the first day of admission resulted in a mean extra stay of 0.3 days (95% CI: 0.1, 0.5) for a patient with an APACHE II score of 10, and 1.2 days (95% CI: 0.5, 2.0) for a patient with an APACHE II score of 30. The decrease in the relative risk of discharge remained fairly constant with day of MRSA infection, but was slightly stronger closer to the start of infection. These results confirm the importance of MRSA infection in increasing ICU stay, but suggest that previous work may have systematically overestimated the effect size.

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Following an early claim by Nelson & McEvoy suggesting that word associations can display `spooky action at a distance behaviour', a serious investigation of the potentially quantum nature of such associations is currently underway. In this paper quantum theory is proposed as a framework suitable for modelling the mental lexicon, specifically the results obtained from both intralist and extralist word association experiments. Some initial models exploring this hypothesis are discussed, and they appear to be capable of substantial agreement with pre-existing experimental data. The paper concludes with a discussion of some experiments that will be performed in order to test these models.

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Phase-type distributions represent the time to absorption for a finite state Markov chain in continuous time, generalising the exponential distribution and providing a flexible and useful modelling tool. We present a new reversible jump Markov chain Monte Carlo scheme for performing a fully Bayesian analysis of the popular Coxian subclass of phase-type models; the convenient Coxian representation involves fewer parameters than a more general phase-type model. The key novelty of our approach is that we model covariate dependence in the mean whilst using the Coxian phase-type model as a very general residual distribution. Such incorporation of covariates into the model has not previously been attempted in the Bayesian literature. A further novelty is that we also propose a reversible jump scheme for investigating structural changes to the model brought about by the introduction of Erlang phases. Our approach addresses more questions of inference than previous Bayesian treatments of this model and is automatic in nature. We analyse an example dataset comprising lengths of hospital stays of a sample of patients collected from two Australian hospitals to produce a model for a patient's expected length of stay which incorporates the effects of several covariates. This leads to interesting conclusions about what contributes to length of hospital stay with implications for hospital planning. We compare our results with an alternative classical analysis of these data.

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The title of this book, Hard Lesson: Reflections on Crime control in Late Modernity, contains a number of clues about its general theoretical direction. It is a book concerned, fist and foremost, with the vagaries of crime control in western neo-liberal and English speaking countries. More specifically, Hard Lessons draws attention to a number of examples in which discrete populations – those who have in one way or another offended against the criminal law - have become the subjects of various forms of stare intervention, regulation and control. We are concerned most of all with the ways in which recent criminal justice policies and practices have resulted in what are variously described as unintended consequences, unforeseen outcomes, unanticipated results, counter-productive effects or negative side effects. At their simplest, such terms refer to the apparent gulf between intention and outcome; they often form the basis for considerable amount of policy reappraisal, soul searching and even nihilistic despair among the mamandirns of crime control. Unintended consequences can, of course, be both positive and negative. Occasionally, crime control measures may result in beneficial outcomes, such as the use of DNA to acquit wrongly convicted prisoners. Generally, however, unforeseen effects tend to be negative and even entirely counterproductive, and/or directly opposite to what were originally intended. All this, of course, presupposes some sort of rational, well meaning and transparent policy making process so beloved by liberal social policy theorists. Yet, as Judith Bessant points out in her chapter, this view of policy formulation tends to obscure the often covert, regulatory and downright malevolent intentions contained in many government policies and practices. Indeed, history is replete with examples of governments seeking to mask their real aims from a prying public eye. Denials and various sorts of ‘techniques of neutralisation’ serve to cloak the real or ‘underlying’ aims of the powerful (Cohen 2000). The latest crop of ‘spin doctors’ and ‘official spokespersons’ has ensured that the process of governmental obfuscation, distortion and concealment remains deeply embedded in neo-liberal forms of governance. There is little new or surprising in this; nor should we be shocked when things ‘go wrong’ in the domain of crime control since many unintended consequences are, more often than not, quite predictable. Prison riots, high rates of recidivism and breaches of supervision orders, expansion rather than contraction of control systems, laws that create the opposite of what was intended – all these are normative features of western crime control. Indeed, without the deep fault lines running between policy and outcome it would be hard to imagine what many policy makers, administrators and practitioners would do: their day to day work practices and (and incomes) are directly dependent upon emergent ‘service delivery’ problems. Despite recurrent howls of official anguish and occasional despondency it is apparent that those involved in the propping up the apparatus of crime control have a vested interest in ensuring that polices and practices remain in an enduring state of review and reform.

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Excessive consumption of alcohol is a serious public health problem. While intensive treatments are suitable for those who are physically dependent on alcohol, they are not cost-effective options for the vast majority of problem drinkers who are not dependent. There is good evidence that brief interventions are effective in reducing overall alcohol consumption, alcohol-related problems, and health-care utilisation among nondependent problem drinkers. Psychologists are in an ideal position to opportunistically detect people who drink excessively and to offer them brief advice to reduce their drinking. In this paper we outline the process involved in providing brief opportunistic screening and intervention for problem drinkers. We also discuss methods that psychologists can employ if a client is not ready to reduce drinking, or is ambivalent about change. Depending on the client's level of motivation to change, psychologists can engage in either an education-clarification approach, a commitment-enhancement approach, or a skills-training approach. Routine engagement in opportunistic intervention is an important public-health approach to reducing alcohol-related harm in the community.

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Objective: This study examines the association between maternal anxiety from pregnancy to 5 years and child attention problems at 5 and 14 years. Method: Birth cohort of 3,982 individuals born in Brisbane between 1981 and 1983 are assessed. Self-reported measures of maternal anxiety are assessed at four time points. Maternal reports of child attention problems using Achenbach’s Child Behavior Checklist are assessed at 5 and 14 years. Results: Children of mothers experiencing anxiety during or after pregnancy are at greater risk of experiencing attention problems at 5 and 14 years. After adjusting for maternal age and child’s gender, antenatal anxiety is strongly associated with persistent attention problems (OR = 3.65, 95% CI = 2.19, 6.07). Children with chronically anxious mothers are 5.67 (95% CI = 3.56, 9.03) times more likely to have persistent attention problems. These associations remain consistent after adjusting for potential confounders. Conclusions: Maternal anxiety appears to increase the rate of child attention problems and identifies a need for treatment programs to have a dual focus—the mother and her child. (J. of Att. Dis. 2009; XX(X) 1-XX)

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Science has been under attack in the last thirty years, and recently a number of prominent scientists have been busy fighting back. Here, an argument is presented that the `science wars' stem from an unreasonably strict adherence to the reductive method on the part of science, but that weakening this stance need not imply a lapse into subjectivity. One possible method for formalising the description of non-separable, contextually dependent complex systems is presented. This is based upon a quantum-like approach.

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New models of human cognition inspired by quantum theory could underpin information technologies that are better aligned with howwe recall information.