1,667 research outputs found

    Non locality, closing the detection loophole and communication complexity

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    It is shown that the detection loophole which arises when trying to rule out local realistic theories as alternatives for quantum mechanics can be closed if the detection efficiency η\eta is larger than ηd1/220.0035d\eta \geq d^{1/2} 2^{-0.0035d} where dd is the dimension of the entangled system. Furthermore it is argued that this exponential decrease of the detector efficiency required to close the detection loophole is almost optimal. This argument is based on a close connection that exists between closing the detection loophole and the amount of classical communication required to simulate quantum correlation when the detectors are perfect.Comment: 4 pages Latex, minor typos correcte

    Partitioning Edge-Colored Hypergraphs into Few Monochromatic Tight Cycles

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    Confirming a conjecture of Gy´arf´as, we prove that, for all natural numbers k and r, the vertices of every r-edge-colored complete k-uniform hypergraph can be partitioned into a bounded number (independent of the size of the hypergraph) of monochromatic tight cycles. We further prove that, for all natural numbers p and r, the vertices of every r-edge-colored complete graph can be partitioned into a bounded number of pth powers of cycles, settling a problem of Elekes, Soukup, Soukup, and Szentmikl´ossy [Discrete Math., 340 (2017), pp. 2053–2069]. In fact we prove a common generalization of both theorems which further extends these results to all host hypergraphs of bounded independence number

    Quantum Weakly Nondeterministic Communication Complexity

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    We study the weakest model of quantum nondeterminism in which a classical proof has to be checked with probability one by a quantum protocol. We show the first separation between classical nondeterministic communication complexity and this model of quantum nondeterministic communication complexity for a total function. This separation is quadratic.Comment: 12 pages. v3: minor correction

    Full Scale Proton Beam Impact Testing of new CERN Collimators and Validation of a Numerical Approach for Future Operation

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    New collimators are being produced at CERN in the framework of a large particle accelerator upgrade project to protect beam lines against stray particles. Their movable jaws hold low density absorbers with tight geometric requirements, while being able to withstand direct proton beam impacts. Such events induce considerable thermo-mechanical loads, leading to complex structural responses, which make the numerical analysis challenging. Hence, an experiment has been developed to validate the jaw design under representative conditions and to acquire online results to enhance the numerical models. Two jaws have been impacted by high-intensity proton beams in a dedicated facility at CERN and have recreated the worst possible scenario in future operation. The analysis of online results coupled to post-irradiation examinations have demonstrated that the jaw response remains in the elastic domain. However, they have also highlighted how sensitive the jaw geometry is to its mounting support inside the collimator. Proton beam impacts, as well as handling activities, may alter the jaw flatness tolerance value by ±\pm 70 μ{\mu}m, whereas the flatness tolerance requirement is 200 μ{\mu}m. In spite of having validated the jaw design for this application, the study points out numerical limitations caused by the difficulties in describing complex geometries and boundary conditions with such unprecedented requirements.Comment: 22 pages, 17 figures, Prepared for submission to JINS

    Professionalism, golf coaching and a master of science degree

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    A distinction can be made between 'professionalisation', which is concerned with occupational status and standing, and 'professionalism,' which refers to matters of quality and standards of practice (especially specialized knowledge, ethics and altruism). The purpose of this stimulus article is to present key features of contemporary medical professionalism as a basis for critically reflecting on discourse associated with Tiger Woods' current coach, Sean Foley. It is suggested that that provision of a Master of Science degree in golf teaching/coaching would facilitate the development of 'professionalism' in golf coaches

    Refugees, trauma and adversity-activated development

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    The nature of the refugee phenomenon is examined and the position of mental health professionals is located in relation to it. The various uses of the word 'trauma' are explored and its application to the refugee context is examined. It is proposed that refugees' response to adversity is not limited to being traumatized but includes resilience and Adversity-Activated Development (AAD). Particular emphasis is given to the distinction between resilience and AAD. The usefulness of the 'Trauma Grid' in the therapeutic process with refugees is also discussed. The Trauma Grid avoids global impressions and enables a more comprehensive and systematic way of identifying the individual refugee's functioning in the context of different levels, i.e. individual, family, community and society/culture. Finally, I discuss implications for therapeutic work with refugees

    CHEMICAL MODIFICATION OF CELLULOSE

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    Thermolytic degradation of cellulose is dependant on its initial DP, accessibility and on the method and temperature of the treatment. A limiting DP could be detected in the depolymerizing reaction. The deteriorating action of aggressive water could be demonstrated. Quantitative correlation was elaborated concerning the role of accessibility in the reaction between cellulose and reactive dyestuffs. The role of temperature was cleared up in the ceIlulose-caustic soda interaction. New bleaching process was elaborated with the use of singlet oxygen. Physical characteristics, amount of releasable formaldehyde and colouristic influence of resin finishing of cotton could be optimized

    Diagonally Neighbour Transitive Codes and Frequency Permutation Arrays

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    Constant composition codes have been proposed as suitable coding schemes to solve the narrow band and impulse noise problems associated with powerline communication. In particular, a certain class of constant composition codes called frequency permutation arrays have been suggested as ideal, in some sense, for these purposes. In this paper we characterise a family of neighbour transitive codes in Hamming graphs in which frequency permutation arrays play a central rode. We also classify all the permutation codes generated by groups in this family

    An exploration of bullying behaviours in nursing : a review of the literature

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    This article explores bullying behaviours in nursing in the United Kingdom and other countries, why it happens and suggests actions to prevent or combat it. Bullying involves intentional and repeated psychological violence humiliating and isolating staff from colleagues. Current literature reports that 20-25% of nursing staff experience bullying behaviour. The main perpetrators are nurses in a senior position to those being bullied and colleagues who are established staff members. Those likely to be bullied are students and new staff members. Bullying can cause distress and depression, with up to 25 per cent of those bullied leaving their jobs or the profession, and have an impact on patient care. Factors contributing to bullying are hierarchical management and employees not feeling empowered. Silence and inaction by managers and colleagues allows this behaviour to continue. A zero tolerance and the addressing of this behaviour clearly and promptly by managers should be instigated. Staff being bullied should be supported by colleague
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