Scaling Behavior of Response Functions in the Coarsening Dynamics of Disordered Ferromagnets

We study coarsening dynamics in the ferromagnetic random bond Ising model in d = 1; 2. We focus on the validity of super-universality and the scaling properties of the response functions. In the d = 1 case, we obtain a complete understanding of the evolution, from pre- asymptotic to asymptotic behavior. The corresponding response function shows a clear violation of super-universality. Further, our results for d = 1; 2 settle the controversy regarding the decay exponent which characterizes the response function

Study of non-equilibrium effects and thermal properties of heavy ion collisions using a covariant approach

Non-equilibrium effects are studied using a full Lorentz-invariant formalism. Our analysis shows that in reactions considered here, no global or local equilibrium is reached. The heavier masses are found to be equilibrated more than the lighter systems. The local temperature is extracted using hot Thomas Fermi formalism generalized for the case of two interpenetrating pieces of nuclear matter. The temperature is found to vary linearly with bombarding energy and impact parameter whereas it is nearly independent of the mass of the colliding nuclei. This indicates that the study of temperature with medium size nuclei is also reliable. The maximum temperatures obtained in our approach are in a nice agreement with earlier calculations of other approaches. A simple parametrization of maximal temperature as a function of the bombarding energy is also given.Comment: LaTex-file, 17 pages, 8 figures (available upon request), Journal of Physics G20 (1994) 181

Crossover in Growth Law and Violation of Superuniversality in the Random Field Ising Model

We study the nonconserved phase ordering dynamics of the d = 2, 3 random field Ising model, quenched to below the critical temperature. Motivated by the puzzling results of previous work in two and three di- mensions, reporting a crossover from power-law to logarithmic growth, together with superuniversal behavior of the correlation function, we have undertaken a careful investigation of both the domain growth law and the autocorrelation function. Our main results are as follows: We confirm the crossover to asymptotic logarithmic behavior in the growth law, but, at variance with previous findings, the exponent in the preasymptotic power law is disorder-dependent, rather than being the one of the pure system. Furthermore, we find that the autocorre- lation function does not display superuniversal behavior. This restores consistency with previous results for the d = 1 system, and fits nicely into the unifying scaling scheme we have recently proposed in the study of the random bond Ising model.Comment: To be published in Physical Review

Cavity-QED with cold atoms trapped in a double-well potential

We investigate the interplay dynamics of a cavity qed system, where the two-level atoms are trapped in a double-well potential, and the cavity mode, with a frequency largely detuned to the atomic level splitting, is driven by a probe laser. The interaction between the center-of-mass motion of the atoms and the cavity mode is induced by the position dependent atom-field coupling. The dynamics of the system is characterized by two distinct time scales, the inverse of the atomic interwell tunneling rate and the inverse of the cavity loss rate. The system shows drastically different (quasi) steady behaviors in the short-time and long-time intervals.Comment: 8 pages, 5 figue

Amplification of Fluctuations in Unstable Systems with Disorder

We study the early-stage kinetics of thermodynamically unstable systems with quenched disorder. We show analytically that the growth of initial fluctuations is amplified by the presence of disorder. This is confirmed by numerical simulations of morphological phase separation (MPS) in thin liquid films and spinodal decomposition (SD) in binary mixtures. We also discuss the experimental implications of our results.Comment: 15 pages, 4 figure

Executive function in first-episode schizophrenia

BACKGROUND: We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-episode patients. Previous studies have shown either equal decrements in many cognitive domains or specific deficits in memory. Such studies have grouped test results or have used few executive measures, thus, possibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function. METHODS: Thirty first-episode schizophrenic patients and 30 normal volunteers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from the Cambridge Automated Neuropsychological Test Battery. Computerized and traditional tests of memory were also administered for comparison. RESULTS: Patients were worse on all tests but the profile was non-uniform. A componential analysis indicated that the patients were characterized by a poor ability to think ahead and organize responses but an intact ability to switch attention and inhibit prepotent responses. Patients also demonstrated poor memory, especially for free recall of a story and associate learning of unrelated word pairs. CONCLUSIONS: In contradistinction to previous studies, schizophrenic patients do have profound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set shifting, which is generally unimpaired. Previous findings in more chronic patients, of severe attentional set shifting impairment, suggest that executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first episode suggests that cognitive deficits are not restricted to one cognitive domain

Barriers and opportunities to restricting marketing of unhealthy foods and beverages to children in Nepal: a policy analysis

BACKGROUND: Marketing of foods and non-alcoholic beverages high in saturated fats, trans-fatty acids, free sugars, or salt (“unhealthy foods”) to children is contributing to increasing child obesity. However, many countries have not implemented WHO recommendations to restrict marketing of unhealthy foods to children. We sought to understand the absence of marketing restrictions and identify potential strategic actions to develop and implement such restrictions in Nepal. METHODS: Eighteen semi-structured interviews were conducted. Thematic analysis was based on Baker et al.’s 18 factor-framework for understanding what drives political commitment to nutrition, organised by five categories: Actors; Institutions; Political and societal contexts; Knowledge, evidence and framing; Capacities and resources. RESULTS: All factors in Baker et al.’s framework were reported to be acting largely as barriers to Nepal developing and implementing marketing restrictions. Six factors were identified by the highest number of respondents: the threat of private sector interference in policy-making; lack of international actor support; absence of well-designed and enacted policies and legislation; lack of political commitment to regulate; insufficient mobilisation of existing evidence to spur action and lack of national evidence to guide regulatory design; and weak implementation capacity. Opportunities for progress were identified as Nepal’s ability to combat private sector interference - as previously demonstrated in tobacco control. CONCLUSIONS: This is the first study conducted in Nepal examining the lack of restrictions on marketing unhealthy foods to children. Our findings reflect the manifestation of power in the policy process. The absence of civil society and a multi-stakeholder coalition demanding change on marketing of unhealthy food to children, the threat of private sector interference in introducing marketing restrictions, the promotion of norms and narratives around modernity, consumption and the primary role of the individual in regulating diet - all have helped create a policy vacuum on marketing restrictions. We propose that stakeholders focus on five strategic actions, including: developing a multi-stakeholder coalition to put and keep marketing restrictions on the health agenda; framing the need for marketing restrictions as critical to protect child rights and government regulation as the solution; and increasing support, particularly through developing more robust global policy guidance

Stability Constants of Glutamic Acid Complexes with Some Metal Ions

1021-102

Thermochemical Studies on Ternary Systems: Part I-Enthalpies of Mixing of Polyoxyethylene Glycols in Aqueous Dioxane & Ethyl Alcohol

645-64

Electronic correlations in FeGa3 and the effect of hole doping on its magnetic properties

We investigate signatures of electronic correlations in the narrow-gap semiconductor FeGa 3 by means of electrical resistivity and thermodynamic measurements performed on single crystals of FeGa 3 , Fe 1−x Mn x Ga 3 , and FeGa 3−y Zn y , complemented by a study of the 4d analog material RuGa 3 . We find that the inclusion of sizable amounts of Mn and Zn dopants into FeGa 3 does not induce an insulator-to-metal transition. Our study indicates that both substitution of Zn onto the Ga site and replacement of Fe by Mn introduces states into the semiconducting gap that remain localized even at highest doping levels. Most importantly, using neutron powder diffraction measurements, we establish that FeGa 3 orders magnetically above room temperature in a complex structure, which is almost unaffected by the doping with Mn and Zn. Using realistic many-body calculations within the framework of dynamical mean field theory (DMFT), we argue that while the iron atoms in FeGa 3 are dominantly in an S=1 state, there are strong charge and spin fluctuations on short-time scales, which are independent of temperature. Further, the low magnitude of local contributions to the spin susceptibility advocates an itinerant mechanism for the spin response in FeGa 3 . Our joint experimental and theoretical investigations classify FeGa 3 as a correlated band insulator with only small dynamical correlation effects, in which nonlocal exchange interactions are responsible for the spin gap of 0.4 eV and the antiferromagnetic order. We show that hole doping of FeGa 3 leads, within DMFT, to a notable strengthening of many-body renormalizations