803 research outputs found
Multiplicity of periodic solutions for systems of weakly coupled parametrized second order differential equations
We prove a multiplicity result of periodic solutions for a system of second order differential equations having asymmetric nonlinearities. The proof is based on a recent generalization of the Poincar\ue9\u2013Birkhoff fixed point theorem provided by Fonda and Ure\uf1a
Measuring Gaussian rigidity using curved substrates
The Gaussian (saddle splay) rigidity of fluid membranes controls their
equilibrium topology but is notoriously difficult to measure. In lipid
mixtures, typical of living cells, linear interfaces separate liquid ordered
(LO) from liquid disordered (LD) bilayer phases at subcritical temperatures.
Here we consider such membranes supported by curved supports that thereby
control the membrane curvatures. We show how spectral analysis of the
fluctuations of the LO-LD interface provides a novel way of measuring the
difference in Gaussian rigidity between the two phases. We provide a number of
conditions for such interface fluctuations to be both experimentally measurable
and sufficiently sensitive to the value of the Gaussian rigidity, whilst
remaining in the perturbative regime of our analysis.Comment: 5 pages, 3 figures. v2: version accepted for publicatio
INTRINSIC MECHANISM FOR ENTROPY CHANGE IN CLASSICAL AND QUANTUM EVOLUTION
It is shown that the existence of a time operator in the Liouville space
representation of both classical and quantum evolution provides a mechanism for
effective entropy change of physical states. In particular, an initially
effectively pure state can evolve under the usual unitary evolution to an
effectively mixed state.Comment: 20 pages. For more information or comments contact E. Eisenberg at
[email protected] (internet)
Comparison of analytical functions used to describe topside electron density profiles with satellite data
Electron density models of the ionosphere use different analytical formulations for the electron density vertical
profile in the topside. The present paper compares some single-layer topside analytical descriptions (Chapman,
Epstein, modified Epstein used in the NeQuick model) with experimental topside profiles obtained from measurements
of IK19 and ISIS2 satellites. The limits of height range and shape for each formulation are described
and analyzed and suggestions for the use of multiple layers solution to reproduce experimental results are given
'Sexercise': Working out heterosexuality in Jane Fondaâs fitness books
This is an Author's Accepted Manuscript of an article published in Leisure Studies, 30(2), 237 - 255, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/02614367.2010.523837.This paper explores the connection between the promotion of heterosexual norms in womenâs fitness books written by or in the name of Jane Fonda during the 1980s and the commodification of womenâs fitness space in both the public and private spheres. The paper is set in the absence of overt discussions of normative heterosexuality in leisure studies and draws on critical heterosexual scholarship as well as the growing body of work theorising geographies of corporeality and heterosexuality. Using the principles of media discourse analysis, the paper identifies three overlapping characteristics of heterosexuality represented in Jane Fondaâs fitness books, and embodied through the exercise regimes: respectable heterosexual desire, monogamous procreation and domesticity. The paper concludes that the promotion and prescription of exercise for women in the Jane Fonda workout books centred on the reproduction and embodiment of heterosexual corporeality. Set within an emerging commercial landscape of womenâs fitness in the 1980s, such exercise practices were significant in the legitimation and institutionalisation of heteronormativity
Exponential behavior of a quantum system in a macroscopic medium
An exponential behavior at all times is derived for a solvable dynamical
model in the weak-coupling, macroscopic limit. Some implications for the
quantum measurement problem are discussed, in particular in connection with
dissipation.Comment: 8 pages, report BA-TH/94-17
The various power decays of the survival probability at long times for free quantum particle
The long time behaviour of the survival probability of initial state and its
dependence on the initial states are considered, for the one dimensional free
quantum particle. We derive the asymptotic expansion of the time evolution
operator at long times, in terms of the integral operators. This enables us to
obtain the asymptotic formula for the survival probability of the initial state
, which is assumed to decrease sufficiently rapidly at large .
We then show that the behaviour of the survival probability at long times is
determined by that of the initial state at zero momentum . Indeed,
it is proved that the survival probability can exhibit the various power-decays
like for an arbitrary non-negative integers as ,
corresponding to the initial states with the condition as .Comment: 15 pages, to appear in J. Phys.
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