1,476 research outputs found

    Coherent States, Dynamics and Semiclassical Limit on Quantum Groups

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    Coherent states on the quantum group SUq(2)SU_q(2) are defined by using harmonic analysis and representation theory of the algebra of functions on the quantum group. Semiclassical limit q1q\rightarrow 1 is discussed and the crucial role of special states on the quantum algebra in an investigation of the semiclassical limit is emphasized. An approach to qq-deformation as a qq-Weyl quantization and a relavence of contact geometry in this context is pointed out. Dynamics on the quantum group parametrized by a real time variable and corresponding to classical rotations is considered.Comment: 20 pages in latex, SFU-HEP-108-9

    Antinociceptive, antipyretic and anti-inflammatory effects of Clerodendrum phlomidis in mice and rats

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    The ethanolic extract of Clerodendrum phlomidis L. belonging to the family of Verbenaceae was evaluated for its antinociceptive, antipyretic and anti-inflammatory activity in mice and rats respectively. Analgesic activity was studied by using acetic acid-induced mouse withering test, hot water tail immersion method and eddy’s hot plate method in mice. The antipyretic activity was evaluated against yeast induced pyroxia in rat and anti-inflammatory activity was evaluated by carrageenan-induced hind paw edema and its probable mechanism evaluated in rats. The preliminary phytochemical screening and acute toxicity studies were carried out. C. phlomidis extract showed a dose dependent significant reduction of the number of writhes (

    Scattering of polarized laser light by an atomic gas in free space: a QSDE approach

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    We propose a model, based on a quantum stochastic differential equation (QSDE), to describe the scattering of polarized laser light by an atomic gas. The gauge terms in the QSDE account for the direct scattering of the laser light into different field channels. Once the model has been set, we can rigorously derive quantum filtering equations for balanced polarimetry and homodyne detection experiments, study the statistics of output processes and investigate a strong driving, weak coupling limit.Comment: 9 pages, 2 figure

    Stability of Hill Slopes and Foundation Condition at Radio Astronomy Centre Ootacamand

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    Stability aspects of hill slopes and foundation considerations of Radio Astronomy Centre at Ootacamand are described. The analysis of slopes indicated that if joints are not covered, the material in joints may lose strength and the slopes may enter a state of instability. Footings with inclined legs were found to resist the horizontal forces, pull and overturning movements. Lime piles adopted for strengthening soft material at one of the tower locations were found to be effective

    Neocortical dendritic complexity is controlled during development by NOMA-GAP-dependent inhibition of Cdc42 and activation of cofilin

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    Neocortical neurons have highly branched dendritic trees that are essential for their function. Indeed, defects in dendritic arborization are associated with human neurodevelopmental disorders. The molecular mechanisms regulating dendritic arbor complexity, however, are still poorly understood. Here, we uncover the molecular basis for the regulation of dendritic branching during cortical development. We show that during development, dendritic branching requires post-mitotic suppression of the RhoGTPase Cdc42. By generating genetically modified mice, we demonstrate that this is catalyzed in vivo by the novel Cdc42-GAP NOMA-GAP. Loss of NOMA-GAP leads to decreased neocortical volume, associated specifically with profound oversimplification of cortical dendritic arborization and hyperactivation of Cdc42. Remarkably, dendritic complexity and cortical thickness can be partially restored by genetic reduction of post-mitotic Cdc42 levels. Furthermore, we identify the actin regulator cofilin as a key regulator of dendritic complexity in vivo. Cofilin activation during late cortical development depends on NOMA-GAP expression and subsequent inhibition of Cdc42. Strikingly, in utero expression of active cofilin is sufficient to restore postnatal dendritic complexity in NOMA-GAP-deficient animals. Our findings define a novel cell-intrinsic mechanism to regulate dendritic branching and thus neuronal complexity in the cerebral cortex

    Towards the solution of the CP/CAC_{P}/C_{A} anomaly in shell-model calculations of muon capture

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    Recently many authors have performed shell-model calculations of nuclear matrix elements determining the rates of the ordinary muon capture in light nuclei. These calculations have employed well-tested effective interactions in large scale shell-model studies. For one of the nuclei of interest, namely 28^{28}Si, there exists recent experimental data which can be used to deduce the value of the ratio CP/CAC_{P}/C_{A} by using the calculated matrix elements. Surprisingly enough, all the abovementioned shell-model results suggest a very small value (0\simeq 0) for CP/CAC_{P}/C_{A}, quite far from the PCAC prediction and recent data on muon capture in hydrogen. We show that this rather disturbing anomaly is solved by employing effective transition operators. This finding is also very important in studies of the scalar coupling of the weak charged current of leptons and hadrons.Comment: Revtex, 6 pages, 2 figs include

    Use of approximations of Hamilton-Jacobi-Bellman inequality for solving periodic optimization problems

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    We show that necessary and sufficient conditions of optimality in periodic optimization problems can be stated in terms of a solution of the corresponding HJB inequality, the latter being equivalent to a max-min type variational problem considered on the space of continuously differentiable functions. We approximate the latter with a maximin problem on a finite dimensional subspace of the space of continuously differentiable functions and show that a solution of this problem (existing under natural controllability conditions) can be used for construction of near optimal controls. We illustrate the construction with a numerical example.Comment: 29 pages, 2 figure

    Pulsations and Long-Term Light Variability of Three Candidates to Protoplanetary Nebulae

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    We present new photometric data and analysis of the long-duration UBV photoelectric observations for three candidates to protoplanetary objects - F-supergiants with IR-excesses located at large galactic latitudes, IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All three stars have revealed quasiperiodic low-amplitude variabilities caused by pulsations observed against the long-term trends of brightnesses. For IRAS 18095+2704=V887 Her we have found a pulsation period of 109 days and a linear trend of brightness under the constant colours if being averaged over the year timescale. The light curve of IRAS 19386+0155=V1648 Aql over 2000-2008 can be approximated by a wave with a main period of 102 days which is modulated by close frequency, with a period of 98 days, that results in brightness oscillations with a variable amplitude. V1648 Aql has also shown synchronous reddening together with a persistent rise of brightness in the V-band. IRAS 19500-1709=V5112 Sgr experiences irregular pulsations with the periods of 39 and 47 days. The long-term component of the variability of V5112 Sgr may be related to the binary character of this star.Comment: 11 pages, 6 figures, accepted for publication in Pis'ma Astron. Z

    Stability, Gain, and Robustness in Quantum Feedback Networks

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    This paper concerns the problem of stability for quantum feedback networks. We demonstrate in the context of quantum optics how stability of quantum feedback networks can be guaranteed using only simple gain inequalities for network components and algebraic relationships determined by the network. Quantum feedback networks are shown to be stable if the loop gain is less than one-this is an extension of the famous small gain theorem of classical control theory. We illustrate the simplicity and power of the small gain approach with applications to important problems of robust stability and robust stabilization.Comment: 16 page
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