24,454 research outputs found

    Hamilton's theory of turns revisited

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    We present a new approach to Hamilton's theory of turns for the groups SO(3) and SU(2) which renders their properties, in particular their composition law, nearly trivial and immediately evident upon inspection. We show that the entire construction can be based on binary rotations rather than mirror reflections.Comment: 7 pages, 4 figure

    OR14-3OPIOID SUBSTITUTION TREATMENT: FROM LAW TO CLINICAL PRACTICE AND VICE VERSA

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    Background. On the edge of the >, the Neuchatel Institute of Health Law compared regulations for opioid substitution treatment (OST) in Switzerland, France, Canada, Belgium and Tunisia. Most standards described appear to be linked to a historic repressive framework. Reference to the right to health as defined by the Committee on Economic, Social and Cultural Rights (general comment 14), appear to be absent or unclear. We present the rational for creating an interdisciplinary panel from the concerned countries, in order to prepare recommendations about how a regulative system of OST should be based on scientific evidence and right to health. Method. Following a literature review identifying barriers to best practice from an addiction medicine point of view, a DELFI technique will identify the domains requiring removal or implementation of regulations, as a priority. Results and Conclusion. Based on the report of comparative law cited above, following areas need to be considered: access to care and free choice to treatment; the articulation of different laws; conditions for authorisation; concerned substances and products; personal conditions posed to patients and professionals; requirements and limitations surrounding substitution treatment itself; the terms of ending or interruption; the protection of personal dat

    Communication and equilibrium in discontinuous games of incomplete information

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    This paper offers a new approach to the study of economic problems usually modeled as games of incomplete information with discontinuous payoffs. Typically, the discontinuities arise from indeterminacies (ties) in the underlying problem. The point of view taken here is that the tie-breaking rules that resolve these indeterminacies should be viewed as part of the solution rather than part of the description of the model. A solution is therefore a tie-breaking rule together with strategies satisfying the usual best-response criterion. When information is incomplete, solutions need not exist; that is, there may be no tie-breaking rule that is compatible with the existence of strategy profiles satisfying the usual best-response criteria. It is shown that the introduction of incentive compatible communication (cheap talk) restores existence

    Evaluating the Prevalence of Illegal Structures Development in Osogbo, Southwest Nigeria

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    The study was designed to assess construction of illegal structures in Osogbo, Osun State, Nigeria. The specific objectives of the study include assessing the level of awareness of the respondents on national building regulation. The research examined the level of illegal structures in Osogbo and identified strategies to curb the incidence factors that account for the construction. In the methodology, a sample size of 142 was chosen for the study. Questionnaire administration and personal observation were deployed to elicit vital data from the respondents and the professional allies. Data generated from the survey were analyzed using the statistical tools such as descriptive statistics (percentages and frequencies) and the relative importance index. Findings revealed that 42% of the structures in Osogbo metropols was exclusively constructed without official permit or approval from relevant authorities; 58% of the existing structures had illegal modification whilst, illegal additions accounted for 71.7% of the structures. The findings of the survey indicated that institutional, physical, educational and socio-economic factors aided the proliferation of illegal development in the city. Observation further revealed that all the illegal structures in Osogbo were owned by the educated elites and such structures were either not completely occupied, thus attesting that the educated residents are major violators of building construction regulations. Findings further revealed that, imposition of high penalties on culprits by the local authority, automating of permit acquisition, monitoring and detection of illegal building operations are amongst the measures which could be instituted to address such a problem. The study concluded that there should be regular public education on building regulations. Moreover, there should be public-private partnership in curbing illegal structures and automating Permit acquisition, monitoring and detection of new structures by the authorities concerned

    The Real Symplectic Groups in Quantum Mechanics and Optics

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    text of abstract (We present a utilitarian review of the family of matrix groups Sp(2n,)Sp(2n,\Re), in a form suited to various applications both in optics and quantum mechanics. We contrast these groups and their geometry with the much more familiar Euclidean and unitary geometries. Both the properties of finite group elements and of the Lie algebra are studied, and special attention is paid to the so-called unitary metaplectic representation of Sp(2n,)Sp(2n,\Re). Global decomposition theorems, interesting subgroups and their generators are described. Turning to nn-mode quantum systems, we define and study their variance matrices in general states, the implications of the Heisenberg uncertainty principles, and develop a U(n)-invariant squeezing criterion. The particular properties of Wigner distributions and Gaussian pure state wavefunctions under Sp(2n,)Sp(2n,\Re) action are delineated.)Comment: Review article 43 pages, revtex, no figures, replaced because somefonts were giving problem in autometic ps generatio

    The formation of supermassive black holes in the first galaxies

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    We discuss the formation of supermassive black holes in the early universe, and how to probe their subsequent evolution with the upcoming mm/sub-mm telescope ALMA. We first focus on the chemical and radiative conditions for black hole formation, in particular considering radiation trapping and molecular dissociation effects. We then turn our attention towards the magnetic properties in the halos where the first black holes form, and show that the presence of turbulence may lead to a magnetic dynamo, which could support the black hole formation process by providing an efficient means of transporting the angular momentum. We finally focus on observable properties of high-redshift black holes with respect to ALMA, and discuss how to distinguish between chemistry driven by the starburst and chemistry driven by X-rays from the black hole.Comment: Contribution to AIP conference proceedings "First Stars and Galaxies: Challenges in the Next Decade". 4 pages, 3 figure

    Part of the D - dimensional Spiked harmonic oscillator spectra

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    The pseudoperturbative shifted - l expansion technique PSLET [5,20] is generalized for states with arbitrary number of nodal zeros. Interdimensional degeneracies, emerging from the isomorphism between angular momentum and dimensionality of the central force Schrodinger equation, are used to construct part of the D - dimensional spiked harmonic oscillator bound - states. PSLET results are found to compare excellenly with those from direct numerical integration and generalized variational methods [1,2].Comment: Latex file, 20 pages, to appear in J. Phys. A: Math. & Ge

    Entanglement conditions for two-mode states: Applications

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    We examine the implications of several recently derived conditions [Hillery and Zubairy, Phys. Rev. Lett. 96, 050503 (2006)] for determining when a two-mode state is entangled. We first find examples of non-Gaussian states that satisfy these conditions. We then apply the entanglement conditions to the study of several linear devices, the beam splitter, the parametric amplifier, and the linear phase-insensitive amplifier. For the first two, we find conditions on the input states that guarantee that the output states are entangled. For the linear amplifier, we determine in the limit of high and no gain, when an entangled input leads to an entangled output. Finally, we show how application of two two-mode entanglement conditions to a three-mode state can serve as a test of genuine three-mode entanglement.Comment: 7 pages, no figures, replaced with published versio

    Random Surfing Without Teleportation

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    In the standard Random Surfer Model, the teleportation matrix is necessary to ensure that the final PageRank vector is well-defined. The introduction of this matrix, however, results in serious problems and imposes fundamental limitations to the quality of the ranking vectors. In this work, building on the recently proposed NCDawareRank framework, we exploit the decomposition of the underlying space into blocks, and we derive easy to check necessary and sufficient conditions for random surfing without teleportation.Comment: 13 pages. Published in the Volume: "Algorithms, Probability, Networks and Games, Springer-Verlag, 2015". (The updated version corrects small typos/errors

    Omega-3 Fatty Acids Improve Recovery, whereas Omega-6 Fatty Acids Worsen Outcome, after Spinal Cord Injury in the Adult Rat

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    Spinal cord injury (SCI) is a cause of major neurological disability, and no satisfactory treatment is currently available. Evidence suggests that polyunsaturated fatty acids (PUFAs) could target some of the pathological mechanisms that underlie damage after SCI. We examined the effects of treatment with PUFAs after lateral spinal cord hemisection in the rat. The ω-3 PUFAs α-linolenic acid and docosahexaenoic acid (DHA) injected 30 min after injury induced significantly improved locomotor performance and neuroprotection, including decreased lesion size and apoptosis and increased neuronal and oligodendrocyte survival. Evidence showing a decrease in RNA/DNA oxidation suggests that the neuroprotective effect of ω-3 PUFAs involved a significant antioxidant function. In contrast, animals treated with arachidonic acid, an ω-6 PUFA, had a significantly worse outcome than controls. We confirmed the neuroprotective effect of ω-3 PUFAs by examining the effects of DHA treatment after spinal cord compression injury. Results indicated that DHA administered 30 min after spinal cord compression not only greatly increased survival of neurons but also resulted in significantly better locomotor performance for up to 6 weeks after injury. This report shows a striking difference in efficacy between the effects of treatment with ω-3 and ω-6 PUFAs on the outcome of SCI, with ω-3 PUFAs being neuroprotective and ω-6 PUFAs having a damaging effect. Given the proven clinical safety of ω-3 PUFAs, our observations show that these PUFAs have significant therapeutic potential in SCI. In contrast, the use of preparations enriched in ω-6 PUFAs after injury could worsen outcome after SCI
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