El desarrollo de la investigación educativa y sus vinculaciones con el gobierno de la educación en América Latina

Este artículo se basa en un estudio comparado sobre las cambiantes relaciones —en especial, desde la década de 1960 hasta la actualidad— entre las instituciones y prácticas especializadas de producción de conocimiento y el gobierno del sistema educativo en seis países latinoamericanos (Argentina, Brasil, Chile, México, Paraguay y Uruguay). Luego de una breve discusión teórica, el artículo se divide en dos partes: en la primera se hace un rápido recorrido histórico de la investigación educativa en América Latina y, en la segunda, se desarrolla un análisis de los seis casos en torno a dos dimensiones: 1) el crecimiento, diferenciación y especialización de prácticas, agentes e instituciones de investigación educativas, y 2) las capacidades estatales para regular la vinculación entre agencias productoras de conocimiento y los organismos y prácticas de planificación y gobierno.This article is based on a comparative study of the changing relationships —in particular, from the 1960s to the present— among specialized institutions and specialized practices of knowledge production in the governmental education system in six Latin American countries (Argentina, Brazil, Chile, Mexico, Paraguay and Uruguay). Atfer a brief theoretical discussion, the paper is divided into two parts: the first provides a quick historical overview of educational research in Latin America and, in the second part, there is an analysis of the six country cases with regard to two aspects: 1) the growth, differentiation and specialization of practices, agents and institutions of educational research, and 2) the state’s capacity to regulate the relationship between knowledge-producing agencies and the organizations, planning practices and government

Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in Phys. Rev. Let

On the relative expressiveness of higher-order session processes

By integrating constructs from the λ-calculus and the π-calculus, in higher-order process calculi exchanged values may contain processes. This paper studies the relative expressiveness of HOπ, the higher-order π-calculus in which communications are governed by session types. Our main discovery is that HO, a subcalculus of HOπ which lacks name-passing and recursion, can serve as a new core calculus for session-typed higher-order concurrency. By exploring a new bisimulation for HO, we show that HO can encode HOπ fully abstractly (up to typed contextual equivalence) more precisely and efficiently than the first-order session π-calculus (π). Overall, under session types, HOπ, HO, and π are equally expressive; however, HOπ and HO are more tightly related than HOπ and π

A Model-Theoretic Reconstruction of the Operational Semantics of Logic Programs

AbstractIn this paper we define a new notion or truth on Herbrand interpretations extended with variables which allows us to capture, by means of suitable models, various observable properties, such as the ground success set, the set of atomic consequences, and the computed answer substitutions. The notion of truth extends the classical one to account for non-ground formulas in the interpretations. The various operational semantics are all models. An ordering on interpretations is defined to overcome the problem that the intersection of a set of models is not necessarily a model. The set of interpretations with this partial order is shown to be a complete lattice, and the greatest lower bound of any set of models is shown to be a model. Thus there exists a least model, which is the least Herbrand model and therefore the ground success set semantics. Richer operational semantics are non-least models, which can, however, be effectively defined by fixpoint constructions. The model corresponding to the computed answer substitutions operational semantics is the most primitive one (the others can easily be obtained from it)

Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis

A criterion for separating process calculi

We introduce a new criterion, replacement freeness, to discern the relative expressiveness of process calculi. Intuitively, a calculus is strongly replacement free if replacing, within an enclosing context, a process that cannot perform any visible action by an arbitrary process never inhibits the capability of the resulting process to perform a visible action. We prove that there exists no compositional and interaction sensitive encoding of a not strongly replacement free calculus into any strongly replacement free one. We then define a weaker version of replacement freeness, by only considering replacement of closed processes, and prove that, if we additionally require the encoding to preserve name independence, it is not even possible to encode a non replacement free calculus into a weakly replacement free one. As a consequence of our encodability results, we get that many calculi equipped with priority are not replacement free and hence are not encodable into mainstream calculi like CCS and pi-calculus, that instead are strongly replacement free. We also prove that variants of pi-calculus with match among names, pattern matching or polyadic synchronization are only weakly replacement free, hence they are separated both from process calculi with priority and from mainstream calculi.Comment: In Proceedings EXPRESS'10, arXiv:1011.601

The GTPase-activating protein RN-tre controls focal adhesion turnover and cell migration.

SummaryBackgroundIntegrin-mediated adhesion of cells to the extracellular matrix (ECM) relies on the dynamic formation of focal adhesions (FAs), which are biochemical and mechanosensitive platforms composed of a large variety of cytosolic and transmembrane proteins. During migration, there is a constant turnover of ECM contacts that initially form as nascent adhesions at the leading edge, mature into FAs as actomyosin tension builds up, and are then disassembled at the cell rear, thus allowing for cell detachment. Although the mechanisms of FA assembly have largely been defined, the molecular circuitry that regulates their disassembly still remains elusive.ResultsHere, we show that RN-tre, a GTPase-activating protein (GAP) for Rabs including Rab5 and Rab43, is a novel regulator of FA dynamics and cell migration. RN-tre localizes to FAs and to a pool of Rab5-positive vesicles mainly associated with FAs undergoing rapid remodeling. We found that RN-tre inhibits endocytosis of β1, but not β3, integrins and delays the turnover of FAs, ultimately impairing β1-dependent, but not β3-dependent, chemotactic cell migration. All of these effects are mediated by its GAP activity and rely on Rab5.ConclusionsOur findings identify RN-tre as the Rab5-GAP that spatiotemporally controls FA remodeling during chemotactic cell migration

Probabilistic Anonymity

The concept of anonymity comes into play in a wide range of situations, varying from voting and anonymous donations to postings on bulletin boards and sending mails. A formal definition of this concept has been given in literature in terms of nondeterminism. In this paper, we investigate a notion of anonymity based on probability theory, and we we discuss the relation with the nondeterministic one. We then formulate this definition in terms of observables for processes in the probabilistic $pi$-calculus, and propose a method to verify automatically the anonymity property. We illustrate the method by using the example of the dining cryptographers

Collagen prolyl hydroxylation-dependent metabolic perturbation governs epigenetic remodeling and mesenchymal transition in pluripotent and cancer cells

Collagen prolyl hydroxylation (CPH), which is catalyzed by prolyl 4-hydroxylase (P4H), is the most prevalent posttranslational modification in humans and requires Vitamin C (VitC). Here we demonstrate that CPH acts as an epigenetic modulator of cell plasticity. Increased CPH induced global DNA/histone methylation in pluripotent stem and tumor cells and promoted cell state transition (CST). Interfering with CPH by either genetic ablation of P4H subunit alpha-2 (P4HA2) or pharmacologic treatment reverted epigenetic changes and antagonized CST. Mechanistically, we suggest that CPH modifies the epigenetic landscape by reducing VitC for DNA and histone demethylases. Repurposed drugs targeting CPH-mediated metabolic perturbation, such as the antiasthmatic Budesonide, blocked metastatic dissemination of breast cancer cells in vivo by preventing mesenchymal transition. Our study provides mechanistic insights into how metabolic cues and epigenetic factors integrate to control cell state transition and paves the way for the development of novel antimetastatic strategies. Significance: A phenotype-based high-throughput screening reveals unforeseen metabolic control of cell plasticity and identifies budesonide as a drug candidate for metastatic cancer

A Finite Representation of the Narrowing Space

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-14125-1_4Narrowing basically extends rewriting by allowing free variables in terms and by replacing matching with unification. As a consequence, the search space of narrowing becomes usually infinite, as in logic programming. In this paper, we introduce the use of some operators that allow one to always produce a finite data structure that still represents all the narrowing derivations. Furthermore, we extract from this data structure a novel, compact equational representation of the (possibly infinite) answers computed by narrowing for a given initial term. Both the finite data structure and the equational representation of the computed answers might be useful in a number of areas, like program comprehension, static analysis, program transformation, etc.Nishida, N.; Vidal, G. (2013). A Finite Representation of the Narrowing Space. En Logic-Based Program Synthesis and Transformation. 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