Phase Transition for Glauber Dynamics for Independent Sets on Regular Trees

We study the effect of boundary conditions on the relaxation time of the Glauber dynamics for the hard-core model on the tree. The hard-core model is defined on the set of independent sets weighted by a parameter $\lambda$, called the activity. The Glauber dynamics is the Markov chain that updates a randomly chosen vertex in each step. On the infinite tree with branching factor $b$, the hard-core model can be equivalently defined as a broadcasting process with a parameter $\omega$ which is the positive solution to $\lambda=\omega(1+\omega)^b$, and vertices are occupied with probability $\omega/(1+\omega)$ when their parent is unoccupied. This broadcasting process undergoes a phase transition between the so-called reconstruction and non-reconstruction regions at $\omega_r\approx \ln{b}/b$. Reconstruction has been of considerable interest recently since it appears to be intimately connected to the efficiency of local algorithms on locally tree-like graphs, such as sparse random graphs. In this paper we show that the relaxation time of the Glauber dynamics on regular $b$-ary trees $T_h$ of height $h$ and $n$ vertices, undergoes a phase transition around the reconstruction threshold. In particular, we construct a boundary condition for which the relaxation time slows down at the reconstruction threshold. More precisely, for any $\omega \le \ln{b}/b$, for $T_h$ with any boundary condition, the relaxation time is $\Omega(n)$ and $O(n^{1+o_b(1)})$. In contrast, above the reconstruction threshold we show that for every $\delta>0$, for $\omega=(1+\delta)\ln{b}/b$, the relaxation time on $T_h$ with any boundary condition is $O(n^{1+\delta + o_b(1)})$, and we construct a boundary condition where the relaxation time is $\Omega(n^{1+\delta/2 - o_b(1)})$

Contribution of Time of Drinking Onset and Family History of Alcohol Problems in Alcohol and Drug Use Behaviors in Argentinean College Students

Aims: The aim of the study was to analyze independent and potential interactive effects of age at drinking onset and family history of alcohol abuse on subsequent patterns of alcohol drinking, alcohol-related problems and substance use. Methods: Participants were college students (60.3% females, mean age = 20.27 ± 2.54 years) from the city of Córdoba, Argentina. Several measures were used to assess alcohol, tobacco and drug use. The Spanish version of the Brief Young Adult Alcohol Consequences Questionnaire was used to assess alcohol-related problems. Factorial analyses of variance, or its non-parametric equivalent, were performed to explore differences in substance use behaviors and alcohol-related problems in subjects with early or late drinking onset and with or without family history of alcohol abuse. Chi-square tests were conducted to analyze the association between these two risk factors and categorical measures of alcohol, tobacco and drug use. Results: Early onset of drinking was associated with amount of consumption of alcohol including up to hazardous levels, as well as tobacco and drug use. However, the frequency of alcohol problems and frequency of episodes of alcohol intoxication were only related to age of onset in those with a positive family history of alcohol problems. Conclusion: Delaying drinking debut is particularly important in the prevention of future alcohol problems in those adolescents who have a family history of such problems.Fil: Pilatti, Angelina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Caneto, Florencia. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Garimaldi, Javier Alejandro. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Vera, Belén del Valle. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin

Web site quality evaluation in Higher Education Institutions

AbstractThere are increasing concerns about the degree of quality delivered on the Web. Considering the competitive environment where Higher Education Institutions (HEI) are inserted, they should, as other organizations do, use their Web sites as a marketing tool. To measure Web site quality we used Aladwani's and Palvia's instrument [2], which evaluates quality from the user's perspective. The main conclusion of our study relates to the fact that HEI aren’t committed to using the Web site as an effective marketing tool and, therefore, much work still needs to be done.Academics are fundamental concerning Web marketing in HEI, since they may contribute to enlarge the knowledge in this area and alert HEI to the role that Web site quality may play in today's extremely turbulent and competitive environment

Competition and performance in European Higher Education: the role of funding instruments. Competición y desempeño en los sistemas europeos de Educación Superior: el papel de los instrumentos de financiación.

Abstract. Higher education institutions face today a demanding and complex context in which they are asked to fulfill multiple roles. Many of these challenges have to be faced in a complex financial context in which traditional modes of funding have been transformed and public sources are not as generous as they often were in the past.Like in many other public services, in recent years it became a rather common statement that higher education institutions should be more efficient in the use of taxpayers’ resources, which had a clear impact in visible changes in the funding of public higher education in Europe. In this paper we will analyse the major trends in higher education funding in Europe and underline to what extent the current debates about higher education and its funding have been significantly influenced by economic considerations. We will identify some of the main issues that dominate the current debate around higher education’s funding, drawing some comparative insights from developments across Europe. Resumen. Las instituciones de Enseñanza Superior están involucradas en un contexto complejo y exigente en el que tienen que hacer frente a múltiples demandas. Muchas de estas demandas emergen en un entorno financiero difícil, las fuentes tradicionales de financiamiento se han trasformado y los fondos públicos no fluyen con la generosidad de antes. Como en muchas áreas del sector público, las instituciones de enseñanza superior están presionadas para tener un uso más eficiente de las subvenciones públicas. Ello se observa como preocupación en los modos de financiamiento de muchos sistemas públicos de Enseñanza Superior en Europa. En este artículo se analizan algunas de las principales tendencias en el financiamiento de Educación Superior pública en Europa subrayando la influencia creciente de los razonamientos económicos en estos sistemas. En el análisis, y a partir de la comparación de algunos casos, seidentificarán algunos de los temas clave en el debate actual sobre el financiamientode la Educación Superior en ese continente