Fluctuations in the random-link matching problem

Using the replica approach and the cavity method, we study the fluctuations of the optimal cost in the random-link matching problem. By means of replica arguments, we derive the exact expression of its variance. Moreover, we study the large deviation function, deriving its expression in two different ways, namely using both the replica method and the cavity method.Comment: 9 pages, 3 figure

The n-acetyl phenylalanine glucosamine derivative attenuates the inflammatory/catabolic environment in a chondrocyte-synoviocyte co-culture system

Osteoarthritis (OA), the most prevalent degenerative joint disease, still lacks a true disease-modifying therapy. The involvement of the NF-κB pathway and its upstream activating kinases in OA pathogenesis has been recognized for many years. The ability of the N-acetyl phenylalanine glucosamine derivative (NAPA) to increase anabolism and reduce catabolism via inhibition of IKKα kinase has been previously observed in vitro and in vivo. The present study aims to confirm the chondroprotective effects of NAPA in an in vitro model of joint OA established with primary cells, respecting both the crosstalk between chondrocytes and synoviocytes and their phenotypes. This model satisfactorily reproduces some features of the previously investigated DMM model, such as the prominent induction of ADAMTS-5 upon inflammatory stimulation. Both gene and protein expression analysis indicated the ability of NAPA to counteract key cartilage catabolic enzymes (ADAMTS-5) and effectors (MCP-1). Molecular analysis showed the ability of NAPA to reduce IKKα nuclear translocation and H3Ser10 phosphorylation, thus inhibiting IKKα transactivation of NF-κB signalling, a pivotal step in the NF-κB-dependent gene expression of some of its targets. In conclusion, our data confirm that NAPA could truly act as a disease-modifying drug in OA

The Random Fractional Matching Problem

We consider two formulations of the random-link fractional matching problem, a relaxed version of the more standard random-link (integer) matching problem. In one formulation, we allow each node to be linked to itself in the optimal matching configuration. In the other one, on the contrary, such a link is forbidden. Both problems have the same asymptotic average optimal cost of the random-link matching problem on the complete graph. Using a replica approach and previous results of W\"{a}stlund [Acta Mathematica 204, 91-150 (2010)], we analytically derive the finite-size corrections to the asymptotic optimal cost. We compare our results with numerical simulations and we discuss the main differences between random-link fractional matching problems and the random-link matching problem.Comment: 24 pages, 3 figure

Perspectivas minimalistas en la investigación psicolingüística

Se presenta una aproximación particular al estudio de los procesos psicolingüísticos, la cual está basada en una aproximación minimalista del lenguaje. Se esboza un modelo procedimental de la adquisición del lenguaje, el cual reconcilia el procesamiento del habla en los niños, y la idea del aprendizaje innatamente guiado, con una visión minimalista del estado inicial de la adquisición del lenguaje en una explicación del problema del arranque. La adquisición del lenguaje es vista como procedente con la especificación progresiva de los rasgos formales de las categorías funcionales del léxico. Se discute la posibilidad de que una derivación minimalista sea incorporada en un modelo de producción y/o comprensión de frases. Se consideran posibles fuentes de impedimentos del lenguaje, como los manifestados en el síndrome TEL (Trastorno Específico del Lenguaje), a la luz de esta aproximación integrativa. Se hace referencia al trabajo experimental llevado a cabo en portugués brasileño, con alguna extensión al portugués europeo y al español del Río de la Plata

Perspectivas minimalistas na pesquisa psicolingüística

A particular approach to the study of psycholinguistic processes is presented, which is based on a minimalist conception of language. A procedural model of language acquisition is sketched, which reconciles infants speech processing and the idea of innately guided learning with a minimalist view of the initial state of language acquisition in an account of the bootstrapping problem. Language acquisition is viewed as proceeding with the progressive specification of formal features of the functional categories of the lexicon. The possibility of a minimalist derivation to be incorporated in a sentence production and/or comprehension model is discussed. Possible sources of language impairment, as manifested in SLI (Specific Language Impairment) syndrome, are considered in the light of this integrative approach. Reference is made to experimental work carried out in Brazilian Portuguese, with some extension to European Portuguese and River-Plate Spanish.Se presenta una aproximación particular al estudio de los procesos psicolingüísticos, la cual está basada en una aproximación minimalista del lenguaje. Se esboza un modelo procedimental de la adquisición del lenguaje, el cual reconcilia el procesamiento del habla en los niños, y la idea del aprendizaje innatamente guiado, con una visión minimalista del estado inicial de la adquisición del lenguaje en una explicación del problema del arranque. La adquisición del lenguaje es vista como procedente con la especificación progresiva de los rasgos formales de las categorías funcionales del léxico. Se discute la posibilidad de que una derivación minimalista sea incorporada en un modelo de producción y/o comprensión de frases. Se consideran posibles fuentes de impedimentos del lenguaje, como los manifestados en el síndrome TEL (Trastorno Específico del Lenguaje), a la luz de esta aproximación integrativa. Se hace referencia al trabajo experimental llevado a cabo en portugués brasileño, con alguna extensión al portugués europeo y al español del Río de la Plata.Apresentase uma abordagem particular para o estudo de processos psicolinguísticos, que tem por base uma concepção minimalista de língua. um modelo procedimental da aquisição da linguagem é esboçado, no qual se conciliam, no tratamento do problema do desenca- deamento da sintaxe, o processamento da fala por infantes aliado à ideia de aprendizagem guiada por fatores inatos, com uma visão minimalista do estado inicial da aquisição da linguagem. A aquisição da linguagem é concebida como a progressiva especificação dos traços formais das categorias funcionais do léxico. Discutese a possibilidade de incorporação de uma derivação minimalista em modelos de produção/compreensão de sentenças. Possíveis fontes de problemas de linguagem, tais como os manifestos no quadro do DEL (Défict Específico da Linguagem), são consideradas à luz dessa abordagem integrada. Remetese a resultados obtidos em experimentos conduzidos em Português Brasileiro, alguns dos quais replicados em Português Europeu e Espanhol Rioplatense.

Random Assignment Problems on 2d Manifolds

We consider the assignment problem between two sets of N random points on a smooth, two-dimensional manifold Ω of unit area. It is known that the average cost scales as EΩ(N) ∼ 1 / 2 πln N with a correction that is at most of order lnNlnlnN. In this paper, we show that, within the linearization approximation of the field-theoretical formulation of the problem, the first Ω -dependent correction is on the constant term, and can be exactly computed from the spectrum of the Laplace–Beltrami operator on Ω. We perform the explicit calculation of this constant for various families of surfaces, and compare our predictions with extensive numerics

Criticality and conformality in the random dimer model

In critical systems, the effect of a localized perturbation affects points that are arbitrarily far from the perturbation location. In this paper, we study the effect of localized perturbations on the solution of the random dimer problem in two dimensions. By means of an accurate numerical analysis, we show that a local perturbation of the optimal covering induces an excitation whose size is extensive with finite probability. We compute the fractal dimension of the excitations and scaling exponents. In particular, excitations in random dimer problems on nonbipartite lattices have the same statistical properties of domain walls in spin glass. Excitations produced in bipartite lattices, instead, are compatible with a loop-erased self-avoiding random walk process. In both cases, we find evidence of conformal invariance of the excitations that is compatible with SLEκ with parameter κ depending on the bipartiteness of the underlying lattice onl