62 research outputs found
Mesoscopic Phase Fluctuations: General Phenomenon in Condensed Matter
General conditions for the occurrence of mesoscopic phase fluctuations in
condensed matter are considered. The description of different thermodynamic
phases, which coexist as a mixture of mesoscopically separated regions, is
based on the {\it theory of heterophase fluctuations}. The spaces of states,
typical of the related phases, are characterized by {\it weighted Hilbert
spaces}. Several models illustrate the main features of heterophase condensed
matter.Comment: 23 pages, Latex, no figure
Mesoscopic Phase Separation in Anisotropic Superconductors
General properties of anisotropic superconductors with mesoscopic phase
separation are analysed. The main conclusions are as follows: Mesoscopic phase
separation can be thermodynamically stable only in the presence of repulsive
Coulomb interactions. Phase separation enables the appearance of
superconductivity in a heterophase sample even if it were impossible in
pure-phase matter. Phase separation is crucial for the occurrence of
superconductivity in bad conductors. Critical temperature for a mixture of
pairing symmetries is higher than the critical temperature related to any pure
gap-wave symmetry of this mixture. In bad conductors, the critical temperature
as a function of the superconductivity fraction has a bell shape. Phase
separation makes the single-particle energy dispersion softer. For planar
structures phase separation suppresses d-wave superconductivity and enhances
s-wave superconductivity. These features are in agreement with experiments for
cuprates.Comment: Revtex file, 25 pages, 2 figure
An asymptotic treatment of the ElenbaasâHeller equation for a radiating wallâstabilized highâpressure gasâdischarge arc
An asymptotic analysis of the ElenbaasâHeller equation for a radiating wall-stabilized high-pressure gas-discharge arc is given. This analysis applies when the operating temperatures within the arc are lower than the ionization temperature by an order of magnitude. It is shown that for arcs that are radiating highly efficiently a further asymptotic treatment can be given. It is shown under what conditions, governed by a dimensionless parameter M, this limiting case prevails. Comparison with earlier results put forward by Zollweg [J. Appl. Phys. 49, 1077 (1978)] shows satisfactory agreement
Basics of Bose-Einstein Condensation
The review is devoted to the elucidation of the basic problems arising in the
theoretical investigation of systems with Bose-Einstein condensate.
Understanding these challenging problems is necessary for the correct
description of Bose-condensed systems. The principal problems considered in the
review are as follows: (i) What is the relation between Bose-Einstein
condensation and global gauge symmetry breaking? (ii) How to resolve the
Hohenberg-Martin dilemma of conserving versus gapless theories? (iii) How to
describe Bose-condensed systems in strong spatially random potentials? (iv)
Whether thermodynamically anomalous fluctuations in Bose systems are
admissible? (v) How to create nonground-state condensates? Detailed answers to
these questions are given in the review. As examples of nonequilibrium
condensates, three cases are described: coherent modes, turbulent superfluids,
and heterophase fluids.Comment: Review articl
Heavy and light roles: myosin in the morphogenesis of the heart
Myosin is an essential component of cardiac muscle, from the onset of cardiogenesis through to the adult heart. Although traditionally known for its role in energy transduction and force development, recent studies
suggest that both myosin heavy-chain and myosin lightchain
proteins are required for a correctly formed heart.
Myosins are structural proteins that are not only expressed
from early stages of heart development, but when mutated
in humans they may give rise to congenital heart defects.
This review will discuss the roles of myosin, specifically
with regards to the developing heart. The expression of
each myosin protein will be described, and the effects that
altering expression has on the heart in embryogenesis in
different animal models will be discussed. The human
molecular genetics of the myosins will also be reviewed
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