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

Damage Spreading in a Driven Lattice Gas Model

We studied damage spreading in a Driven Lattice Gas (DLG) model as a function of the temperature $T$, the magnitude of the external driving field $E$, and the lattice size. The DLG model undergoes an order-disorder second-order phase transition at the critical temperature $T_c(E)$, such that the ordered phase is characterized by high-density strips running along the direction of the applied field; while in the disordered phase one has a lattice-gas-like behaviour. It is found that the damage always spreads for all the investigated temperatures and reaches a saturation value $D_{sat}$ that depends only on $T$. $D_{sat}$ increases for $TT_c(E=\infty)$ and is free of finite-size effects. This behaviour can be explained as due to the existence of interfaces between the high-density strips and the lattice-gas-like phase whose roughness depends on $T$. Also, we investigated damage spreading for a range of finite fields as a function of $T$, finding a behaviour similar to that of the case with $E=\infty$.Comment: 13 pages, 7 figures. Submitted to "Journal of Statistical Mechanics: Theory and Experiment

Speech Genres, of Mikhail Bakhtin

The recent Paulo Bezerra’s translation of Bakhtin’s essay Speech genres (1952-1953) has shed new light on Bakhtin’s dialogic theory. Although the translator has already translated this essay that integrates collection Aesthetics of verbal creation (2003), to pull it apart from the collection to relaunch it along with The text in linguistics, in philology and other human sciences (1959- 1961), he seeks to illuminate some aspects little emphasized in the old translation

Social rights in the face of the crisis. Reflections on the Spanish case

Spain and many European countries are going through a critical stage that endangers the achievements of civilization and protection of social rights which are the standard of the constitutionalism of the social-democratic systems after the Second World War. The emergence of the economic and financial crisis and its impact on Member States, especially in regard to the realization of the rights and, in particular, the social ones, impose a critical reflection since on the European scene there is not a shared concept. In the Spanish social and democratic rule of law, many of the social rights are placed in Chapter III of Title I as guiding principles of social and economic policy. The analysis of this regulatory body of the Constitution is problematic insofar as it raises the problem of redirecting the content of such rules to legal structures in order to ensure guarantee levels which approximate them to fundamental rights within the framework of a European model of social democracy. The problem of the welfare state (in Spain and other European countries) affects the quality of representative democracy

Beta event-related desynchronization as an index of individual differences in processing human facial expression: further investigations of autistic traits in typically developing adults

The human mirror neuron system (hMNS) has been associated with various forms of social cognition and affective processing including vicarious experience. It has also been proposed that a faulty hMNS may underlie some of the deficits seen in the autism spectrum disorders (ASDs). In the present study we set out to investigate whether emotional facial expressions could modulate a putative EEG index of hMNS activation (mu suppression) and if so, would this differ according to the individual level of autistic traits [high versus low Autism Spectrum Quotient (AQ) score]. Participants were presented with 3 s films of actors opening and closing their hands (classic hMNS mu-suppression protocol) while simultaneously wearing happy, angry, or neutral expressions. Mu-suppression was measured in the alpha and low beta bands. The low AQ group displayed greater low beta event-related desynchronization (ERD) to both angry and neutral expressions. The high AQ group displayed greater low beta ERD to angry than to happy expressions. There was also significantly more low beta ERD to happy faces for the low than for the high AQ group. In conclusion, an interesting interaction between AQ group and emotional expression revealed that hMNS activation can be modulated by emotional facial expressions and that this is differentiated according to individual differences in the level of autistic traits. The EEG index of hMNS activation (mu suppression) seems to be a sensitive measure of the variability in facial processing in typically developing individuals with high and low self-reported traits of autism

The influence of US hegemony on the South African anti-trafficking in persons movement

A dissertation presented in partial fulfilment of the requirements for the Masters of Arts Degree in Political Studies, Faculty of the Humanities at the University of the Witwatersrand, Johannesburg, 2016The contemporary movement to end human trafficking rose to prominence in the early to mid 1990s. Following the fall of the Soviet Union, the US found itself in need of new tools to extend its global reach. This report argues that the modern day movement to abolish human trafficking is one of the new tools used to advance US hegemony. South Africa provides a unique context for the study of how US hegemony has been employed through this movement. The rise of this movement coincided with the rise of democracy in the rainbow nation. Under Apartheid, US policy toward South Africa was linked with the fight against communism. The US would channel money to black liberation movements in order to shape their views in a pro-western direction. South Africa was considered important to US economic interests and prosperity. With the communist enemy gone, the US has employed new tools to influence ideology, policy and legislation. Through studying the Anti-Trafficking in Persons (TIP) movement in the South African context, this report analyzes how the movement is a tool of hegemony. Tactics used to gain public consent and legitimize the cause are uncovered, as are coercive measures used to stronghold the South African government to comply with the US.MT201

Role of phosphodiesterase 5 in synaptic plasticity and memory

Phosphodiesterases (PDEs) are enzymes that break down the phosphodiesteric bond of the cyclic nucleotides, cAMP and cGMP, second messengers that regulate many biological processes. PDEs participate in the regulation of signal transduction by means of a fine regulation of cyclic nucleotides so that the response to cell stimuli is both specific and activates the correct third messengers. Several PDE inhibitors have been developed and used as therapeutic agents because they increase cyclic nucleotide levels by blocking the PDE function. In particular, sildenafil, an inhibitor of PDE5, has been mainly used in the treatment of erectile dysfunction but is now also utilized against pulmonary hypertension. This review examines the physiological role of PDE5 in synaptic plasticity and memory and the use of PDE5 inhibitors as possible therapeutic agents against disorders of the central nervous system (CNS)

La crisi economica e la sovranita’ finanziaria statale. Gli atti normativi europei ed i suoi riflessi sugli ordinamenti nazionali

Europa e Italia atraviesan un periodo crítico que pone en peligro las conquistas de civilización y de tutela de los derechos sociales que son el estandarte del constitucionalismo de los ordenamientos democrático-sociales posteriores a la segunda guerra mundial. La aparición de la crisis económico-financiera y sus efectos sobre los Estados miembros, especialmente en lo que respecta a la soberanía financiera, imponen una reflexión crítica tomando como punto de partida las asimetrías existentes en la articulación del poder político decisional de la Unión Europea así como entre ésta y los Estados miembros (y más en concreto los países de la zona euro). La transferencia de la soberanía financiera y monetaria se ha llevado a cabo sin una legitimación democrática y abandonando la idea de un modelo europeo de democracia social. Los efectos se notan especialmente en las entidades infra estatales.