Local cluster aggregation models of explosive percolation

We introduce perhaps the simplest models of graph evolution with choice that demonstrate discontinuous percolation transitions and can be analyzed via mathematical evolution equations. These models are local, in the sense that at each step of the process one edge is selected from a small set of potential edges sharing common vertices and added to the graph. We show that the evolution can be accurately described by a system of differential equations and that such models exhibit the discontinuous emergence of the giant component. Yet, they also obey scaling behaviors characteristic of continuous transitions, with scaling exponents that differ from the classic Erdos-Renyi model.Comment: Final version as appearing in PR

Parallel Implementations of Cellular Automata for Traffic Models

The Biham-Middleton-Levine (BML) traffic model is a simple two-dimensional, discrete Cellular Automaton (CA) that has been used to study self-organization and phase transitions arising in traffic flows. From the computational point of view, the BML model exhibits the usual features of discrete CA, where the state of the automaton are updated according to simple rules that depend on the state of each cell and its neighbors. In this paper we study the impact of various optimizations for speeding up CA computations by using the BML model as a case study. In particular, we describe and analyze the impact of several parallel implementations that rely on CPU features, such as multiple cores or SIMD instructions, and on GPUs. Experimental evaluation provides quantitative measures of the payoff of each technique in terms of speedup with respect to a plain serial implementation. Our findings show that the performance gap between CPU and GPU implementations of the BML traffic model can be reduced by clever exploitation of all CPU features

Cloning and Expression of Multidrug Resistance Genes in the Cabbage Looper Moth, Trichoplusia ni

Three genes encoding multidrug resistance proteins were identified in Trichoplusia ni larvae, named trnMDRl, trnMDR2 and trnMDR3. Their open reading frames were sequenced, and the translated sequences were compared to each other as well as to multidrug resistance proteins from other species. Quantification of their expression in various tissues of caterpillars fed on either artificial diet or organically- grown cabbage revealed upregulation of trnMDRl in Malpighian tubules, integument and fat body, trnMDR2 in fat body and trnMDR3 in brain in response to the plant diet. Sf9 cells stably transformed with either trnMDRl or trnMDR3 were used to assay MDR protein transport of calceinAM and vinblastine, as well as to test the inhibitory effect of cyclosporin A and verapamil on MDR protein activity. No significant calceinAM transport or inhibition of MDR activity by cyclosporin A or verapamil was observed. Cell lines stably transformed with trnMDRl demonstrated increased resistance to vinblastine toxicity. This study suggests that tissue-specific upregulation of MDR protein expression may contribute to caterpillar defences against toxic plant secondary metabolites, and that inhibitors of MDR proteins could be exploited as synergists with pesticides that are detoxified in a similar fashion. The assay system of Sf9 cells transformed with T. ni MDR genes could be used to screen for such potential MDR inhibitors

The Prison Houses of Knowledge: Activist scholarship and revolution in the era of “globalization”

The rise of new social movements has produced an emerging discourse on activist scholarship. There is considerable ambiguity about what the term means. In this article I draw on my work as a trade unionist, political activist, and activist lawyer in Mumbai, and later as a social justice activist in New Zealand to reflect on the meaning of activist scholarship, interrogate the institutional contexts for knowledge, and the relationship of knowledge to emancipatory structural social transformations. Although based on personal experiences, this article provides a theoretically oriented meta-analysis of activist scholarship.La montée des nouveaux mouvements sociaux a provoqué l’émergence d’un discours novateur sur l’activisme étudiant. Il persiste cependant une grande ambiguïté quand à la signification de ce terme. Dans cet article, je m’inspire de mes travaux comme militante syndicale, activiste politique et avocate engagée à Mumbai, ainsi que de mon expérience en tant que activiste en justice sociale en Nouvelle-Zélande pour réfléchir sur le sens à donner à l’activisme étudiant, m’interroger sur les contextes institutionnels du savoir, et sur la relation existant entre le savoir et les transformations structurelles d’émancipation. Bien que prenant appui sur mes expériences personnelles, cet article étaye une méta-analyse théorique de l’activisme étudiant

Assessment of Medium-Sized Ontario Municipalities’ Hiring Practices

This paper examines whether municipalities incorporate equitable principles within their hiring practices and policies. An anonymous online survey was administered to the chief administrative officers, city managers, and human resources personnel of medium-sized municipalities in Ontario working in the capacity of senior level management, as these individuals are known to be the most knowledgeable about hiring practices and employment equity initiatives. The findings demonstrate that, generally speaking, mid-sized Ontario municipalities are not incorporating strategies within their recruitment and selection processes that work towards reducing employment barriers for designated groups

Maritain’s Philosophy of Education and Christian Religious Education

Catholic schools invest much time and energy in writing mission statements that express the common values, beliefs, and goals of the Church community. This article explores the philosophical foundation supporting our mission by analyzing the work of the Catholic philosopher Jacques Maritain. While often labeled dismissively as a new-Thomist, Maritain’s thought offers a cogent, philosophically balanced view of education that is highly congruent with Catholic theology. Arguing that Catholic schools are more than just institutions staffed by Catholics, the author reasons that all education, if the truth be told, is in some form a religious education, and that good teachers create schools that invite students to grow in the life of the mind