Thermodynamics and statistical mechanics of frozen systems in inherent states

We discuss a Statistical Mechanics approach in the manner of Edwards to the ``inherent states'' (defined as the stable configurations in the potential energy landscape) of glassy systems and granular materials. We show that at stationarity the inherent states are distributed according a generalized Gibbs measure obtained assuming the validity of the principle of maximum entropy, under suitable constraints. In particular we consider three lattice models (a diluted Spin Glass, a monodisperse hard-sphere system under gravity and a hard-sphere binary mixture under gravity) undergoing a schematic ``tap dynamics'', showing via Monte Carlo calculations that the time average of macroscopic quantities over the tap dynamics and over such a generalized distribution coincide. We also discuss about the general validity of this approach to non thermal systems.Comment: 10 pages, 16 figure

Time lag between metamorphism and crystallization of anatectic granites (Córdoba, Argentina)

SHRIMP and LA-ICP-MS analyses carried out on zircons from the Río de los Sauces granite revealed their metamorphic and igneous nature. The metamorphic zircons yielded an age of 537±4.8 (2σ)Ma that probably predates the onset of the anatexis during the Pampean orogeny. By contrast, the igneous zircons yielded a younger age of 529±6 (2σ)Ma and reflected its crystallization age. These data point to a short time lag of ca. 8Myr between the High Temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. Concordia age of 534±3.8 (2σ)Ma, for both types of zircon populations, can be considered as the mean age of the Pampean HT metamorphism in the Sierras de Córdoba

Spin and density overlaps in the frustrated Ising lattice gas

We perform large scale simulations of the frustrated Ising lattice gas, a three-dimensional lattice model of a structural glass, using the parallel tempering technique. We evaluate the spin and density overlap distributions, and the corresponding non-linear susceptibilities, as a function of the chemical potential. We then evaluate the relaxation functions of the spin and density self-overlap, and study the behavior of the relaxation times. The results suggest that the spin variables undergo a transition very similar to the one of the Ising spin glass, while the density variables do not show any sign of transition at the same chemical potential. It may be that the density variables undergo a transition at a higher chemical potential, inside the phase where the spins are frozen.Comment: 7 pages, 10 figure

Dynamics of the frustrated Ising lattice gas

The dynamical properties of a three dimensional model glass, the frustrated Ising lattice gas (FILG) are studied by Monte Carlo simulations. We present results of compression experiments, where the chemical potential is either slowly or abruptly changed, as well as simulations at constant density. One time quantities like density and two time ones like correlations, responses and mean square displacements are measured, and the departure from equilibrium clearly characterized. The aging scenario, particularly in the case of density autocorrelations is reminiscent of spin glass phenomenology with violations of the Fluctuation-dissipation theorem, typical of systems with one replica symmetry breaking. The FILG, as a valid on-lattice model of structural glasses can be described with tools developed in spin glass theory and, being a finite dimensional model, can open the way for a systematic study of activated processes in glasses.Comment: to appear in Phys. Rev. E, november (2000

The QCD Phase Structure at High Baryon Density

We consider the possibility that color deconfinement and chiral symmetry restoration do not coincide in dense baryonic matter at low temperature. As a consequence, a state of massive "constituent" quarks would exist as an intermediate phase between confined nuclear matter and the plasma of deconfined massless quarks and gluons. We discuss the properties of this state and its relation to the recently proposed quarkyonic matter.Comment: 17 pages, 9 figure

Relaxation dynamics near the sol–gel transition: From cluster approach to mode-coupling theory

A long standing problem in glassy dynamics is the geometrical interpretation of clusters and the role they play in the observed scaling laws. In this context, the mode-coupling theory (MCT) of type-A transition and the sol–gel transition are both characterized by a structural arrest to a disordered state in which the long-time limit of the correlator continuously approaches zero at the transition point. In this paper, we describe a cluster approach to the sol-gel transition and explore its predictions, including universal scaling laws and a new stretched relaxation regime close to criticality. We show that while MCT consistently describes gelation at mean-field level, the percolation approach elucidates the geometrical character underlying MCT scaling laws

Factorial integrity and validation of the Eating Pathology Symptoms Inventory (EPSI)

The Eating Pathology Symptoms Inventory (EPSI) is a 45-item self-report measure of eating pathology designed to be sensitive in assessing symptoms among diverse populations of individuals with disordered eating. The current study represents the first external validation of the EPSI as well as the first to examine the factor structure in an outpatient eating disorder clinic sample. We conducted an exploratory factor analysis in three separate samples: an outpatient clinic sample (n = 284), a college sample (n = 296), and a community sample (n = 341) and compared the observed factor structures to the original 8-factor solution proposed by Forbush et al. (2013). We also investigated whether the subscales correlated with the Eating Disorder Examination Questionnaire (EDE-Q) and a clinical impairment measure among the outpatient clinic sample. Results suggested between 7 and 8 factors for each

Predictors of long-term recovery in anorexia nervosa and bulimia nervosa: Data from a 22-year longitudinal study

Objective The objective of this study was to investigate predictors of long-term recovery from eating disorders 22 years after entry into a longitudinal study. Method One hundred and seventy-six of the 228 surviving participants (77.2%) were re-interviewed 20-25 years after study entry using the Longitudinal Interval Follow-up Evaluation to assess ED recovery. The sample consisted of 100 women diagnosed with anorexia nervosa (AN) and 76 with bulimia nervosa (BN) at study entry. Results A comorbid diagnosis of major depression at the start of the study strongly predicted having a diagnosis of AN-Restricting type at the 22-year assessment. A higher body mass index (BMI) at study intake decreased the odds of being d

Behavioral inhibition moderates the association between overvaluation of shape and weight and noncompensatory purging in eating disorders

Objective: The cognitive-behavioral therapy (CBT) model of eating disorders suggests that compensatory purging behav