Computable bounds of ℓ2{\ell}^2-spectral gap for discrete Markov chains with band transition matrices

We analyse the $\ell^2(\pi)$-convergence rate of irreducible and aperiodic Markov chains with $N$-band transition probability matrix $P$ and with invariant distribution $\pi$. This analysis is heavily based on: first the study of the essential spectral radius $r\_{ess}(P\_{|\ell^2(\pi)})$ of $P\_{|\ell^2(\pi)}$ derived from Hennion's quasi-compactness criteria; second the connection between the Spectral Gap property (SG$\_2$) of $P$ on $\ell^2(\pi)$ and the $V$-geometric ergodicity of $P$. Specifically, (SG$\_2$) is shown to hold under the condition \alpha\_0 := \sum\_{{m}=-N}^N \limsup\_{i\rightarrow +\infty} \sqrt{P(i,i+{m})\, P^*(i+{m},i)}\ \textless{}\, 1 Moreover $r\_{ess}(P\_{|\ell^2(\pi)}) \leq \alpha\_0$. Effective bounds on the convergence rate can be provided from a truncation procedure.Comment: in Journal of Applied Probability, Applied Probability Trust, 2016. arXiv admin note: substantial text overlap with arXiv:1503.0220

Il n'y a pas de rapport interculturel : vers une approche psycho-socio-pragmatique et dialogique de l'enseignement des langues

The intercultural approach to foreign language teaching is currently undergoing a crisis. It has encountered implementation and assessment difficulties and the major risk is that of falling into the downward spiral of culturalism.This thesis aims to clarify the definition of interculturality, its role in verbal interaction and in the construction of the speaker.It then addresses the relations between the three areas of communicative situations : language, culture and subject. Analysis of a corpus of written asynchronous interaction attempts to determine how these three poles influence each other. More precisely, the question is : how much liberty is left to the subject during speech processing?According to this study, a psycho-socio-pragmatic approach and consideration taken into the dialogic dimension of language would be helpful for some didactic purposes. This study suggests re-focussing language teaching on language and communicative competence and indirect access to interculturality by the mastery of discursive intersubjectivity.L'approche interculturelle en didactique des langues connaît actuellement une crise. Les praticiens rencontrent des difficultés quant à sa mise en place et à son évaluation. En outre, elle montre son incapacité à sortir d'une dérive culturaliste.Cette thèse propose d'abord de clarifier la définition de l'interculturalité, de son rôle dans les échanges verbaux et dans la constitution du sujet parlant.Pour cela, elle s'attache aux relations qui unissent les trois pôles déterminants de la situation de communication : la langue, la culture et le sujet. Une analyse de corpus d'interactions écrites asynchrones tente de déterminer quelles influences les uns peuvent avoir sur les autres. Au final, cela pose la question de la liberté laissée au sujet parlant lors de la genèse du discours.C'est à travers une approche psycho-socio-pragmatique et la considération de la dimension dialogique du langage que des solutions didactiques semblent apparaître. Cette étude suggère de recentrer l'enseignement des langues sur les compétences linguistiques et communicatives et sur un accès indirect à l'interculturalité par la maîtrise de l'intersubjectivité discursive

Feature extraction and signal processing for nylon DNA microarrays

BACKGROUND: High-density DNA microarrays require automatic feature extraction methodologies and softwares. These can be a potential source of non-reproducibility of gene expression measurements. Variation in feature location or in signal integration methodology may be a significant contribution to the observed variance in gene expression levels. RESULTS: We explore sources of variability in feature extraction from DNA microarrays on Nylon membrane with radioactive detection. We introduce a mathematical model of the signal emission and derive methods for correcting biases such as overshining, saturation or variation in probe amount. We also provide a quality metric which can be used qualitatively to flag weak or untrusted signals or quantitatively to modulate the weight of each experiment or gene in higher level analyses (clustering or discriminant analysis). CONCLUSIONS: Our novel feature extraction methodology, based on a mathematical model of the radioactive emission, reduces variability due to saturation, neighbourhood effects and variable probe amount. Furthermore, we provide a fully automatic feature extraction software, BZScan, which implements the algorithms described in this paper

Glutamine as an Immunonutrient

Dietary supplementation with nutrients enhancing immune function is beneficial in patients with surgical and critical illness. Malnutrition and immune dysfunction are common features in hospitalized patients. Specific nutrients with immunological and pharmacological effects, when consumed in amounts above the daily requirement, are referred to as immune-enhancing nutrients or immunonutrients. Supplementation of immunonutrients is important especially for patients with immunodeficiency, virus or overwhelming infections accompanied by a state of malnutrition. Representative immunonutrients are arginine, omega-3 fatty acids, glutamine, nucleotides, beta-carotene, and/or branched-chain amino acids. Glutamine is the most abundant amino acid and performs multiple roles in human body. However, glutamine is depleted from muscle stores during severe metabolic stress including sepsis and major surgery. Therefore it is considered conditionally essential under these conditions. This review discusses the physiological role of glutamine, mode and dose for glutamine administration, as well as improvement of certain disease state after glutamine supplementation. Even though immunonutrition has not been widely assimilated by clinicians other than nutritionists, immunonutrients including glutamine may exert beneficial influence on diverse patient populations

The development of contour processing : evidence from physiology and psychophysics

Object perception and pattern vision depend fundamentally upon the extraction of contours from the visual environment. In adulthood, contour or edge-level processing is supported by the Gestalt heuristics of proximity, collinearity, and closure. Less is known, however, about the developmental trajectory of contour detection and contour integration. Within the physiology of the visual system, long-range horizontal connections in V1 and V2 are the likely candidates for implementing these heuristics. While post-mortem anatomical studies of human infants suggest that horizontal interconnections reach maturity by the second year of life, psychophysical research with infants and children suggests a considerably more protracted development. In the present review, data from infancy to adulthood will be discussed in order to track the development of contour detection and integration. The goal of this review is thus to integrate the development of contour detection and integration with research regarding the development of underlying neural circuitry.We conclude that the ontogeny of this system is best characterized as a developmentally extended period of associative acquisition whereby horizontal connectivity becomes functional over longer and longer distances, thus becoming able to effectively integrate over greater spans of visual space. Keywords

Template-Directed Synthesis of Multiply Mechanically Interlocked Molecules Under Thermodynamic Control

The template-directed construction of crown-ether-like macrocycles around secondary dialkylammonium ions (R2NH2+) has been utilized for the expedient (one-pot) and highyielding synthesis of a diverse range of mechanically interlocked molecules. The clipping together of appropriately designed dialdehyde and diamine compounds around R2NH2+-containing dumbbell-shaped components proceeds through the formation, under thermodynamic control, of imine bonds. The reversible nature of this particular reaction confers the benefits of “errorchecking” and “proof-reading”, which one usually associates with supramolecular chemistry and strict self-assembly processes, upon these wholly molecular systems. Furthermore, these dynamic covalent syntheses exploit the efficient templating effects that the R2NH2+ ions exert on the macrocyclization of the matched dialdehyde and diamine fragments, resulting not only in rapid rates of reaction, but also affording near-quantitative conversion of starting materials into the desired interlocked products. Once assembled, these “dynamic” interlocked compounds can be “fixed” upon reduction of the reversible imine bonds (by using BH3·THF) to give kinetically stable species, a procedure that can be performed in the same reaction vessel as the inital thermodynamically controlled assembly. Isolation and purification of the mechanically interlocked products formed by using this protocol is relatively facile, as no column chromatography is required. Herein, we present the synthesis and characterization of 1) a [2]rotaxane, 2) a [3]rotaxane, 3) a branched [4]rotaxane, 4) a bis [2]rotaxane, and 5) a novel cyclic [4]rotaxane, demonstrating, in incrementally more complex systems, the efficacy of this one-pot strategy for the construction of interlocked molecules

Phénoménologie de l’autre

Ce mémoire est la deuxième étape d'un travail sur une phénoménologie camusienne, qui comprend le M1 sur l'absurde et une thèse qui rassemblera les différents cycles de l'œuvre d'Albert Camus. La question de l'altérité en phénoménologie est ici mêlée au cycle de l'amour chez Camus, qu'il commença à peine avant de mourir, afin de proposer une phénoménologie de l'autre en tant qu'autre et l'idée d'une absurdité commune partagée par l'amour et les sentiments