1,038 research outputs found

    The effect of dietary therapy on abnormal carbohydrate and fat metabolism

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    Condensing Momentum Modes in 2-d 0A String Theory with Flux

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    We use a combination of conformal perturbation theory techniques and matrix model results to study the effects of perturbing by momentum modes two dimensional type 0A strings with non-vanishing Ramond-Ramond (RR) flux. In the limit of large RR flux (equivalently, mu=0) we find an explicit analytic form of the genus zero partition function in terms of the RR flux qq and the momentum modes coupling constant alpha. The analyticity of the partition function enables us to go beyond the perturbative regime and, for alpha>> q, obtain the partition function in a background corresponding to the momentum modes condensation. For momenta such that 0<p<2 we find no obstruction to condensing the momentum modes in the phase diagram of the partition function.Comment: 22 page

    'The Branch on which I sit' Heidi Safia Mirza in conversation with Yasmin Gunaratnam

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    This article is a conversation with Professor Heidi Mirza that discusses her experiences in Higher Education, intersectionality and renewed interest in black feminist ideas among new generations. Heidi Safia Mirza’s work has been concerned with the local and geo-politics of gender, race, faith and culture. She has researched educational inequalities, including young black and Muslim women in school, and the workings of racialisation in higher education

    The diagonalization method in quantum recursion theory

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    As quantum parallelism allows the effective co-representation of classical mutually exclusive states, the diagonalization method of classical recursion theory has to be modified. Quantum diagonalization involves unitary operators whose eigenvalues are different from one.Comment: 15 pages, completely rewritte

    Accuracy and Stability of Computing High-Order Derivatives of Analytic Functions by Cauchy Integrals

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    High-order derivatives of analytic functions are expressible as Cauchy integrals over circular contours, which can very effectively be approximated, e.g., by trapezoidal sums. Whereas analytically each radius r up to the radius of convergence is equal, numerical stability strongly depends on r. We give a comprehensive study of this effect; in particular we show that there is a unique radius that minimizes the loss of accuracy caused by round-off errors. For large classes of functions, though not for all, this radius actually gives about full accuracy; a remarkable fact that we explain by the theory of Hardy spaces, by the Wiman-Valiron and Levin-Pfluger theory of entire functions, and by the saddle-point method of asymptotic analysis. Many examples and non-trivial applications are discussed in detail.Comment: Version 4 has some references and a discussion of other quadrature rules added; 57 pages, 7 figures, 6 tables; to appear in Found. Comput. Mat

    Scaling limit of virtual states of triatomic systems

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    For a system with three identical atoms, the dependence of the s−s-wave virtual state energy on the weakly bound dimer and trimer binding energies is calculated in a form of a universal scaling function. The scaling function is obtained from a renormalizable three-body model with a pairwise Dirac-delta interaction. It was also discussed the threshold condition for the appearance of the trimer virtual state.Comment: 9 pages, 3 figure

    Tunneling of quantum rotobreathers

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    We analyze the quantum properties of a system consisting of two nonlinearly coupled pendula. This non-integrable system exhibits two different symmetries: a permutational symmetry (permutation of the pendula) and another one related to the reversal of the total momentum of the system. Each of these symmetries is responsible for the existence of two kinds of quasi-degenerated states. At sufficiently high energy, pairs of symmetry-related states glue together to form quadruplets. We show that, starting from the anti-continuous limit, particular quadruplets allow us to construct quantum states whose properties are very similar to those of classical rotobreathers. By diagonalizing numerically the quantum Hamiltonian, we investigate their properties and show that such states are able to store the main part of the total energy on one of the pendula. Contrary to the classical situation, the coupling between pendula necessarily introduces a periodic exchange of energy between them with a frequency which is proportional to the energy splitting between quasi-degenerated states related to the permutation symmetry. This splitting may remain very small as the coupling strength increases and is a decreasing function of the pair energy. The energy may be therefore stored in one pendulum during a time period very long as compared to the inverse of the internal rotobreather frequency.Comment: 20 pages, 11 figures, REVTeX4 styl

    Entering the men's domain? Gender and portfolio allocation in European governments

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    While all government portfolios used to be the purview of men exclusively, more and more women are selected to sit around the cabinet table. But under which circumstances do women get appointed to different ministerial portfolios? This article, proposes a theoretical framework to consider how party leaders’ attitudes and motivations influence the allocation of portfolios to male and female ministers. These propositions are tested empirically by bringing together data on 7,005 cabinet appointments across 29 European countries from the late 1980s until 2014. Considering the key partisan dynamics of the ministerial selection process, it is found that women are significantly less likely to be appointed to the ‘core’ offices of state, and ‘masculine’ and ‘neutral’ policy areas. However, these gender differences are moderated by the ideology of the party that allocates them. Women are more likely to be appointed to ‘masculine’ portfolios when a party's voters have more progressive gender attitudes. This theoretical framework and analysis enhances our understanding of women's access to the government, which has important implications for how ministers are selected, as well as how women are represented in the most powerful policy?making positions in Europe

    Hierarchical Spherical Model from a Geometric Point of View

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    A continuous version of the hierarchical spherical model at dimension d=4 is investigated. Two limit distribution of the block spin variable X^{\gamma}, normalized with exponents \gamma =d+2 and \gamma =d at and above the critical temperature, are established. These results are proven by solving certain evolution equations corresponding to the renormalization group (RG) transformation of the O(N) hierarchical spin model of block size L^{d} in the limit L to 1 and N to \infty . Starting far away from the stationary Gaussian fixed point the trajectories of these dynamical system pass through two different regimes with distinguishable crossover behavior. An interpretation of this trajectories is given by the geometric theory of functions which describe precisely the motion of the Lee--Yang zeroes. The large--NN limit of RG transformation with L^{d} fixed equal to 2, at the criticality, has recently been investigated in both weak and strong (coupling) regimes by Watanabe \cite{W}. Although our analysis deals only with N=\infty case, it complements various aspects of that work.Comment: 27 pages, 6 figures, submitted to Journ. Stat. Phy

    Testing neutrino mass matrices with approximate L_e-L_mu-L_tau symmetry

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    As neutrino experiments are starting to probe the detailed structure of the neutrino mass matrix, we present sumrules relating its matrix elements for a class of models with approximate Le−Lμ−LτL_e-L_{\mu}-L_{\tau} symmetry and the observables in neutrino oscillation experiments. We show that regardless of how the above symmetry is broken (whether in the neutrino sector or the charged lepton sector), as long as the breaking terms are small, there is a lower bound on the solar neutrino mixing angle, sin22θ⊙sin^22\theta_{\odot}, correlated with the solar mass difference square, Δm⊙2\Delta m^2_{\odot}, or the mixing parameter, Ue3U_{e3}. We also discuss models where such patterns can arise.Comment: 11 pages, 3 figures; references and a note added; figure labelling fixe
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