9,803 research outputs found

    Parallel hybrid textures of lepton mass matrices

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    We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type CPCP violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.Comment: Physical Review D (To appear

    The eigenspectra of Indian musical drums

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    In a family of drums used in the Indian subcontinent, the circular drum head is made of material of non-uniform density. Remarkably, and in contrast to a circular membrane of uniform density, the low eigenmodes of the non-uniform membrane are harmonic. In this work we model the drum head by a non-uniform membrane whose density varies smoothly between two prescribed values. Using a Fourier-Chebyshev spectral collocation method we obtain the eigenmodes and eigenvalues of the drum head. For a suitable choice of parameters, which we find by optimising a cost function, the eigenspectra obtained from our model are in excellent agreement with experimental values. Our model and the numerical method should find application in numerical sound synthesis

    Effects of physical activity on debilitating behaviours in 13- to 20-year-old males with severe autism spectrum disorder

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    The presented study investigated the extent to which engaging in a therapeutic sporting programme in males with severe Autism Spectrum Disorder (ASD) improves the debilitating behaviours commonly associated with ASD. Furthermore, the views of parents of the autistic participants were assessed concerning the effectiveness of the programme. Participants were eight 13-20 year old males born in the UK from a school and sports college for pupils with severe learning difficulties. The selection was using volunteer sampling from the “Monday Club” initiative, run by Saracens Sports Foundation in partnership with a local School and specialist Sports College. The Gilliam Autism Rating Scale (GARS-3) was administered to identify and measure the severity of ASD behaviours at four time periods namely: at programme entry as the baseline (T1), a second time after 8 weeks (T2), a third time after sixteen weeks (T3) and a fourth time post programme (T4). The results showed that for the more severe cases of ASD (Autism Index >101) there was no positive change in subscale performance from Time1 to Time2. For milder cases (Autism Index 71-100) there were subtle non-significant improvements on the subscale scores from Time1 to Time2. Of the 6 subscales at Time2, Emotional Responses (ER), Cognitive Style (CS) and Maladaptive Speech (MS) approached significance at the p = 0.05 level. At Time3 and Time4, there was also no statistically significant improvement in ASD behaviours compared to the baseline for either condition. Finally parents’ were “very satisfied” with their child’s participation in the physical activity programme

    Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice

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    We experimentally investigate diffraction of a Rb-87 Bose-Einstein condensate from a 1D optical lattice. We use a range of lattice periods and timescales, including those beyond the Raman-Nath limit. We compare the results to quantum mechanical and classical simulations, with quantitative and qualitative agreement, respectively. The classical simulation predicts that the envelope of the time-evolving diffraction pattern is shaped by caustics: singularities in the phase space density of classical trajectories. This behavior becomes increasingly clear as the lattice period grows.Comment: 7 pages, 6 figure

    Vitamin changes in sweets with time and storage conditions

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    Vitamin changes assocd. with different temp. and period of storage were measured in sweets rasmalai and badam pista roll. A comparative study was done between these sweets from two different sweet marts. With std. colorimetric techniques the anal. was carried out and by applying statistical methods the variations were tabulated. The vitamin content (niacin and ascorbic acid) decreased with increase in temp. and storage period in accordance with moisture and pH

    Selection from read-only memory with limited workspace

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    Given an unordered array of NN elements drawn from a totally ordered set and an integer kk in the range from 11 to NN, in the classic selection problem the task is to find the kk-th smallest element in the array. We study the complexity of this problem in the space-restricted random-access model: The input array is stored on read-only memory, and the algorithm has access to a limited amount of workspace. We prove that the linear-time prune-and-search algorithm---presented in most textbooks on algorithms---can be modified to use Θ(N)\Theta(N) bits instead of Θ(N)\Theta(N) words of extra space. Prior to our work, the best known algorithm by Frederickson could perform the task with Θ(N)\Theta(N) bits of extra space in O(NlgN)O(N \lg^{*} N) time. Our result separates the space-restricted random-access model and the multi-pass streaming model, since we can surpass the Ω(NlgN)\Omega(N \lg^{*} N) lower bound known for the latter model. We also generalize our algorithm for the case when the size of the workspace is Θ(S)\Theta(S) bits, where lg3NSN\lg^3{N} \leq S \leq N. The running time of our generalized algorithm is O(Nlg(N/S)+N(lgN)/lgS)O(N \lg^{*}(N/S) + N (\lg N) / \lg{} S), slightly improving over the O(Nlg(N(lgN)/S)+N(lgN)/lgS)O(N \lg^{*}(N (\lg N)/S) + N (\lg N) / \lg{} S) bound of Frederickson's algorithm. To obtain the improvements mentioned above, we developed a new data structure, called the wavelet stack, that we use for repeated pruning. We expect the wavelet stack to be a useful tool in other applications as well.Comment: 16 pages, 1 figure, Preliminary version appeared in COCOON-201

    Biot-Savart correlations in layered superconductors

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    We discuss the superconductor to normal phase transition in an infinite-layered type-II superconductor in the limit where the Josephson coupling between layers is negligible. We model each layer as a neutral gas of thermally excited pancake vortices. We assume the dominant interaction between vortices in the same and in different layers is the electromagnetic interaction between the screening currents induced by these vortices. Our main result, obtained by exactly solving the leading order renormalization group flow, is that the phase transition in this model is a Kosterlitz--Thouless transition despite being a three--dimensional system. While the transition itself is driven by the unbinding of two-dimensional pancake vortices, an RG analysis of the low temperature phase and a mean-field theory of the high temperature phase reveal that both phases possess three-dimensional correlations. An experimental consequence of this is that the jump in the measured in-plane superfluid stiffness, which is a universal quantity in 2d Kosterlitz-Thouless theory, will receive a small non--universal correction (of order 1% in Bi2_2Sr2_2CaCu2_2O8+x_{8+x}). This overall picture places some claims expressed in the literature on a more secure analytical footing and also resolves some conflicting views.Comment: 16 pages, 2 figures; minor typos corrected, references adde
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