Short-Time Critical Dynamics of Damage Spreading in the Two-Dimensional Ising Model

The short-time critical dynamics of propagation of damage in the Ising ferromagnet in two dimensions is studied by means of Monte Carlo simulations. Starting with equilibrium configurations at $T= \infty$ and magnetization $M=0$, an initial damage is created by flipping a small amount of spins in one of the two replicas studied. In this way, the initial damage is proportional to the initial magnetization $M_0$ in one of the configurations upon quenching the system at $T_C$, the Onsager critical temperature of the ferromagnetic-paramagnetic transition. It is found that, at short times, the damage increases with an exponent $\theta_D=1.915(3)$, which is much larger than the exponent $\theta=0.197$ characteristic of the initial increase of the magnetization $M(t)$. Also, an epidemic study was performed. It is found that the average distance from the origin of the epidemic ($\langle R^2(t)\rangle$) grows with an exponent $z^* \approx \eta \approx 1.9$, which is the same, within error bars, as the exponent $\theta_D$. However, the survival probability of the epidemics reaches a plateau so that $\delta=0$. On the other hand, by quenching the system to lower temperatures one observes the critical spreading of the damage at $T_{D}\simeq 0.51 T_C$, where all the measured observables exhibit power laws with exponents $\theta_D = 1.026(3)$, $\delta = 0.133(1)$, and $z^*=1.74(3)$.Comment: 11 pages, 9 figures (included). Phys. Rev. E (2010), in press

Ground-state configuration space heterogeneity of random finite-connectivity spin glasses and random constraint satisfaction problems

We demonstrate through two case studies, one on the p-spin interaction model and the other on the random K-satisfiability problem, that a heterogeneity transition occurs to the ground-state configuration space of a random finite-connectivity spin glass system at certain critical value of the constraint density. At the transition point, exponentially many configuration communities emerge from the ground-state configuration space, making the entropy density s(q) of configuration-pairs a non-concave function of configuration-pair overlap q. Each configuration community is a collection of relatively similar configurations and it forms a stable thermodynamic phase in the presence of a suitable external field. We calculate s(q) by the replica-symmetric and the first-step replica-symmetry-broken cavity methods, and show by simulations that the configuration space heterogeneity leads to dynamical heterogeneity of particle diffusion processes because of the entropic trapping effect of configuration communities. This work clarifies the fine structure of the ground-state configuration space of random spin glass models, it also sheds light on the glassy behavior of hard-sphere colloidal systems at relatively high particle volume fraction.Comment: 26 pages, 9 figures, submitted to Journal of Statistical Mechanic

The Impact of Work-Related Barriers on Job Satisfaction of Practitioners Working with Migrants

Abstract The work environment of practitioners working with migrants may be very demanding as they are frequently exposed to the sad narratives of such a vulnerable population, the lack of professional support, or the frequent change of policies towards refugees and asylum seekers. Little research has been conducted to explore the job satisfaction of practitioners working with migrants and the organizational characteristics that can hinder or promote such satisfaction. The present study investigated the relationship between work-related barriers (i.e., intra-organizational, legal, and interaction-related barriers) and job satisfaction of practitioners working with migrants, also testing if perceived organizational efficacy is mediating this relation. This study was part of a larger European funded project, and participants were 428 First-Line Practitioners working with migrants in various sectors (e.g., social and health services, immigration and asylum services, or border guards) and working in several European countries. Data were collected through an online survey in the period between October and December 2020. Results showed that intra-organizational and legal barriers had a negative impact on job satisfaction, while interaction-related barriers did not have any. Perceived organizational efficacy mediated the relationship between two work-related barriers (intra-organizational and interaction-related barriers) and job satisfaction. These findings suggest that organizations working with migrants should focus on addressing intra-organizational and legal barriers, and on implementing actions aimed at building employees’ collective efficacy beliefs to improve their job satisfaction

MicroRNAs and cancer metabolism reprogramming : the paradigm of metformin

Increasing evidence witnesses that cancer metabolism alterations represent a critical hallmark for many types of human tumors. There is a strong need to understand and dissect the molecular mechanisms underlying cancer metabolism to envisage specific biomarkers and underpin critical molecular components that might represent novel therapeutic targets. One challenge, that is the focus of this review, is the reprogramming of the altered metabolism of a cancer cell toward that of un-transformed cell. The anti-hyperglicemic agent, metformin has proven to be effective in reprogramming the metabolism of cancer cells even from those subpopulations endowed with cancer stem like features and very high chemoresistenace to conventional anticancer treatments. A functional interplay involving selective modulation of microRNAs (miRNAs) takes place along the anticancer metabolic effects exerted by metformin. The implications of this interplay will be also discussed in this review

1-Butanol dehydration and oxidation over vanadium phosphate catalysts

The transformation of 1-butanol into either butenes or maleic anhydride was carried out both with and without oxygen, using V/P/O catalysts. With vanadyl pyrophosphate prepared by coprecipitation, at temperature lower than 240 ◦C and without oxygen, selectivity to butenes was higher than 90%, but a slow deactivation took place. At temperature higher than 300 ◦C and in the presence of air, maleic and phthalic anhydrides were the prevailing products, with selectivity of 60% and 14%, respectively. Catalytic performance was affected by crystallinity and acidity. αI-VOPO4 showed a poor performance in the absence of air, with a quick deactivation due to coke accumulation; but it displayed an excellent selectivity to butenes (close to 98%) at temperatures lower than 320 ◦C in the presence of air, with stable performance. At temperature higher than 360 ◦C, α I-VOPO4 was reduced to vanadyl pyrophosphate and catalyzed the direct oxidation of 1-butanol into maleic anhydride, but with 35% selectivit

Clarifying the Roles of Schizotypy and Psychopathic Traits in Lexical Decision Performance

Brunel University London College of Health, Medicine, and Life Sciences Doctoral Scholarships; Erasmus Mobility programm

Scenario-specific aberrations of social reward processing in dimensional schizotypy and psychopathy

Data availability: The datasets generated and/or analysed for the investigations reported in this paper are available in the OSF repository, https://osf.io/fp6qb/, https://doi.org/10.17605/OSF.IO/FP6QB.Copyright © The Author(s) 2022. The feelings of reward associated with social interaction help to motivate social behaviour and influence preferences for different types of social contact. In two studies conducted in a general population sample, we investigated self-reported and experimentally-assessed social reward processing in personality spectra with prominent interpersonal features, namely schizotypy and psychopathy. Study 1 (n = 154) measured social reward processing using the Social Reward Questionnaire, and a modified version of a Monetary and Social Incentive Delay Task. Study 2 (n = 42; a subsample of Study 1) investigated social reward processing using a Social Reward Subtype Incentive Delay Task. Our results show that schizotypy (specifically Cognitive-Perceptual dimension) and psychopathy (specifically Lifestyle dimension) are associated with diverging responses to social scenarios involving large gatherings or meeting new people (Sociability), with reduced processing in schizotypy and heightened processing in psychopathy. No difference, however, occurred for other social scenarios—with similar patterns of increased antisocial (Negative Social Potency) and reduced prosocial (Admiration, Sociability) reward processing across schizotypy and psychopathy dimensions. Our findings contribute new knowledge on social reward processing within these personality spectra and, with the important exception of Sociability, highlight potentially converging patterns of social reward processing in association with schizotypy and psychopathy.L.A.W and M.V. were supported by Brunel University London College of Health, Medicine, and Life Sciences Doctoral Scholarships and L.E. was supported by Erasmus+ programme

Exact relations between damage spreading and thermodynamic functions for the N-color Ashkin-Teller model

Exact results are derived relating quantities computable by the so-called damage spreading method and thermodynamic functions for the N-color Ashkin-Teller model. The results are valid for any ergodic dynamics. Since we restrict our analysis to the ferromagnetic case the results are also valid for any translational invariant lattice. The derived relations should be used in order to determine numerically the N-color Ashkin-Teller critical exponents with better accuracy and less computational efforts than standard Monte Carlo simulations.Comment: 6 pages, to be published in JSTAT (Journal of Statistical Mechanics: Theory and Experiment). The results of a computer simulation were included for N=3 as an example on how to use the analytical relations derived in the paper as a guide to obtain the critical temperature and critical exponent