969 research outputs found

    Rotating day and night disturb growth hormone secretion profiles, body energy metabolism, and insulin levels in mice

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    Background: Insulin and growth hormone (GH) - 2 vital metabolic regulatory hormones - regulate glucose, lipid, and energy metabolism. These 2 hormones determine substrate and energy metabolism under different living conditions. Shift of day and night affects the clock system and metabolism probably through altered insulin and GH secretion. Methods: Five-week-old male mice were randomly assigned to a rotating light (RL) group (3-day normal light/dark cycle followed by 4-day reversed light/dark cycle per week) and normal light (NL) group. Body weight and food intake were recorded every week. Series of blood samples were collected for pulsatile GH analysis, glucose tolerance test, and insulin tolerance test at 9, 10, and 11 weeks from the start of intervention, respectively. Indirect calorimetric measurement was performed, and body composition was tested at 12 weeks. Expressions of energy and substrate metabolism-related genes were evaluated in pituitary and liver tissues at the end of 12-week intervention. Results: The RL group had an increased number of GH pulsatile bursts and reduced GH mass/burst. RL also disturbed the GH secretion regularity and mode. It suppressed insulin secretion, which led to a disturbed insulin/GH balance. It was accompanied by the reduced metabolic flexibility and modified gene expression involved in energy balance and substrate metabolism. Indirect calorimeter recording revealed that RL decreased the respiratory exchange ratio (RER) and oxygen consumption at the dark phase, which resulted in an increase in fat mass and free fatty acid levels in circulation. Conclusion: RL disturbed pulsatile GH secretion and decreased insulin secretion in male mice with significant impairment in energy, substrate metabolism, and body composition.Diabetes mellitus: pathophysiological changes and therap

    Phase transitions in geometrothermodynamics

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    Using the formalism of geometrothermodynamics, we investigate the geometric properties of the equilibrium manifold for diverse thermodynamic systems. Starting from Legendre invariant metrics of the phase manifold, we derive thermodynamic metrics for the equilibrium manifold whose curvature becomes singular at those points where phase transitions of first and second order occur. We conclude that the thermodynamic curvature of the equilibrium manifold, as defined in geometrothermodynamics, can be used as a measure of thermodynamic interaction in diverse systems with two and three thermodynamic degrees of freedom

    Cardy condition for open-closed field algebras

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    Let VV be a vertex operator algebra satisfying certain reductivity and finiteness conditions such that CV\mathcal{C}_V, the category of V-modules, is a modular tensor category. We study open-closed field algebras over V equipped with nondegenerate invariant bilinear forms for both open and closed sectors. We show that they give algebras over certain \C-extension of the Swiss-cheese partial dioperad, and we obtain Ishibashi states easily in such algebras. We formulate Cardy condition algebraically in terms of the action of the modular transformation S:τ↊−1τS: \tau \mapsto -\frac{1}{\tau} on the space of intertwining operators. We then derive a graphical representation of S in the modular tensor category CV\mathcal{C}_V. This result enables us to give a categorical formulation of Cardy condition and modular invariant conformal full field algebra over V⊗VV\otimes V. Then we incorporate the modular invariance condition for genus-one closed theory, Cardy condition and the axioms for open-closed field algebra over V equipped with nondegenerate invariant bilinear forms into a tensor-categorical notion called Cardy CV∣CV⊗V\mathcal{C}_V|\mathcal{C}_{V\otimes V}-algebra. We also give a categorical construction of Cardy CV∣CV⊗V\mathcal{C}_V|\mathcal{C}_{V\otimes V}-algebra in Cardy case.Comment: 70 page, 105 figures, references are updated. less typos, to appear in Comm. Math. Phy

    Franck-Condon Effect in Central Spin System

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    We study the quantum transitions of a central spin surrounded by a collective-spin environment. It is found that the influence of the environmental spins on the absorption spectrum of the central spin can be explained with the analog of the Franck-Condon (FC) effect in conventional electron-phonon interaction system. Here, the collective spins of the environment behave as the vibrational mode, which makes the electron to be transitioned mainly with the so-called "vertical transitions" in the conventional FC effect. The "vertical transition" for the central spin in the spin environment manifests as, the certain collective spin states of the environment is favored, which corresponds to the minimal change in the average of the total spin angular momentum.Comment: 8 pages, 8 figure

    Topological Charged Black Holes in High Dimensional Spacetimes and Their Formation from Gravitational Collapse of a Type II Fluid

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    Topological charged black holes coupled with a cosmological constant in R2×XD−2R^{2}\times X^{D-2} spacetimes are studied, where XD−2X^{D-2} is an Einstein space of the form (D−2)RAB=k(D−3)hAB{}^{(D-2)}R_{AB} = k(D-3) h_{AB}. The global structure for the four-dimensional spacetimes with k=0k = 0 is investigated systematically. The most general solutions that represent a Type IIII fluid in such a high dimensional spacetime are found, and showed that topological charged black holes can be formed from the gravitational collapse of such a fluid. When the spacetime is (asymptotically) self-similar, the collapse always forms black holes for k=0,−1k = 0, -1, in contrast to the case k=1k = 1, where it can form either balck holes or naked singularities.Comment: 14 figures, to appear in Phys. Rev.

    Young and Intermediate-age Distance Indicators

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    Distance measurements beyond geometrical and semi-geometrical methods, rely mainly on standard candles. As the name suggests, these objects have known luminosities by virtue of their intrinsic proprieties and play a major role in our understanding of modern cosmology. The main caveats associated with standard candles are their absolute calibration, contamination of the sample from other sources and systematic uncertainties. The absolute calibration mainly depends on their chemical composition and age. To understand the impact of these effects on the distance scale, it is essential to develop methods based on different sample of standard candles. Here we review the fundamental properties of young and intermediate-age distance indicators such as Cepheids, Mira variables and Red Clump stars and the recent developments in their application as distance indicators.Comment: Review article, 63 pages (28 figures), Accepted for publication in Space Science Reviews (Chapter 3 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

    A statistical interpretation of the correlation between intermediate mass fragment multiplicity and transverse energy

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    Multifragment emission following Xe+Au collisions at 30, 40, 50 and 60 AMeV has been studied with multidetector systems covering nearly 4-pi in solid angle. The correlations of both the intermediate mass fragment and light charged particle multiplicities with the transverse energy are explored. A comparison is made with results from a similar system, Xe+Bi at 28 AMeV. The experimental trends are compared to statistical model predictions.Comment: 7 pages, submitted to Phys. Rev.

    Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and Îœp nucleosynthesis processes

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    © 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∌10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous Îœp-process simulations.Peer reviewe

    Interacting Ghost Dark Energy in Non-Flat Universe

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    A new dark energy model called "ghost dark energy" was recently suggested to explain the observed accelerating expansion of the universe. This model originates from the Veneziano ghost of QCD. The dark energy density is proportional to Hubble parameter, ρD=αH\rho_D=\alpha H, where α\alpha is a constant of order ΛQCD3\Lambda_{\rm QCD}^3 and ΛQCD∌100MeV\Lambda_{\rm QCD}\sim 100 MeV is QCD mass scale. In this paper, we extend the ghost dark energy model to the universe with spatial curvature in the presence of interaction between dark matter and dark energy. We study cosmological implications of this model in detail. In the absence of interaction the equation of state parameter of ghost dark energy is always wD>−1w_D > -1 and mimics a cosmological constant in the late time, while it is possible to have wD<−1w_D < -1 provided the interaction is taken into account. When k=0k = 0, all previous results of ghost dark energy in flat universe are recovered. To check the observational consistency, we use Supernova type Ia (SNIa) Gold sample, shift parameter of Cosmic Microwave Background radiation (CMB) and the Baryonic Acoustic Oscillation peak from Sloan Digital Sky Survey (SDSS). The best fit values of free parameter at 1σ1\sigma confidence interval are: Ωm0=0.35−0.03+0.02\Omega_m^0= 0.35^{+0.02}_{-0.03}, ΩD0=0.75−0.04+0.01\Omega_D^0=0.75_{-0.04}^{+0.01} and b2=0.08−0.03+0.03b^2=0.08^{+0.03}_{-0.03}. Consequently the total energy density of universe at present time in this model at 68% level equates to Ωtot0=1.10−0.05+0.02\Omega_{\rm tot}^0=1.10^{+0.02}_{-0.05}.Comment: 19 pages, 9 figures. V2: Added comments, observational consequences, references, figures and major corrections. Accepted for publication in General Relativity and Gravitatio

    Analytical solutions to zeroth-order dispersion relations of a cylindrical metallic nanowire

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    Zeroth-order complex dispersion relations of a cylindrical metallic nanowire have been solved out analytically with approximate methods. The analytical solutions are valid for the sections of the dispersion relations whose frequencies are close to the Surface Plasmon frequency. The back bending of the Surface Plasmon-Polaritons(SPPs) can be well described by the analytical solutions, confirming that the back bending is originated from the metal Ohmic loss. The utility of the back bending point in the dispersion relation for the measurement of the metallic Ohimc loss has also been suggested.Comment: 6pages, 3figure
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