224,621 research outputs found
On the problem of phase transitions in lysozyme crystals
We present experimental evidence of the fact that lysozyme crystals, which
are grown from their mother solution and exist in it, dissolve on heating above
T=307 K. We argue that the anomaly in the light scattering recently observed at
the temperature T=307 K and identified in the reference [Svanidze A. V. et al.
2006. JETP Lett. 84: 551] as a structural crystalline phase transition in the
single lysozyme crystals, in fact, corresponds to a temperature limit of the
crystal existence.Comment: 6 pages, 1 figur
Power prior elicitation in Bayesian quantile regression
This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2011 Rahim Alhamzawi and Keming Yu.We address a quantile dependent prior for Bayesian quantile regression. We extend the idea of the power prior distribution in Bayesian quantile regression by employing the likelihood function that is based on a location-scale mixture representation of the asymmetric Laplace distribution. The propriety of the power prior is one of the critical issues in Bayesian analysis. Thus, we discuss the propriety of the power prior in Bayesian quantile regression. The methods are illustrated with both simulation and real data
Energy Estimates and Gravitational Collapse
We study the cancelations in the energy estimates for Einstein vacuum
equations in order to prove the formation of black holes along evolutions. The
novelty of the paper is that, we completely avoid using rotation vector fields
to establish the global existence theorem of the solution. More precisely, we
use only canonical null directions as commutators to derive energy estimates at
the level of one derivatives of null curvature components.Comment: 2 figures, 40 page
Description of lattice anharmonicity observed in ferroelectrics with unusual three-well local potential
For SnPS family of uniaxial ferroelectrics, the anharmonic
quantum oscillators model, based on local three-well potential for spontaneous
polarization fluctuations, has been used for a description of anharmonic
properties, namely thermal expansion. The calculated pseudospin fluctuations
spectra in ferroelectric phase demonstrate negative Gr\"{u}neisen parameters
for excitations that satisfy Curie-Weiss-like temperature and pressure
dependencies in the vicinity of second order phase transition. Thermal
expansion coefficient is calculated by evaluation of pseudospins entropy baric
dependence. Negative thermal expansion in the ferroelectric phase of
SnPS crystal is obtained which is in agreement with observed
experimental data.Comment: 6 pages, 5 figure
- …