Evidence on individual preferences for longevity risk

The standard model of intertemporal choice assumes risk neutrality toward the length of life: due to additivity, agents are not sensitive to a mean preserving spread in the length of life. Using a survey fielded in the RAND American Life Panel (ALP), this paper provides empirical evidence on possible deviation from risk neutrality with respect to longevity in the U.S. population. The questions we ask allow to find the distribution as well as to quantify the degree of risk aversion with respect to the length of life in the population. We find evidence that roughly 75% of respondents were not neutral with respect to longevity risk. Higher income households are more likely to be risk averse. We do not find evidence that the degree of risk aversion varies with age or education

Codage et classification non supervisée d'un corpus maya : extraire des contextes pour situer l'inconnu par rapport au connu

International audienceL'écriture logosyllabique des anciens Mayas comprend plus de 500 signes et est en bonne partie déchiffrée, avec des degrés de certitude divers. Nous avons appliqué au codex de Dresde, l'un des trois seuls manuscrits qui nous soient parvenus, codé sous LATEX avec le système mayaTEX, notre méthode de représentation graduée, par apprentissage non supervisé hybride entre clustering et analyse factorielle oblique, sous la métrique de Hellinger, afin d'obtenir une image nuancée des thèmes traités : les individus statistiques sont les 212 segments de folio du codex, et leurs attributs sont les 1687 bigrammes de signes extraits. Pour comparaison, nous avons introduit dans cette approche endogène un élément exogène, la décomposition en éléments des signes composites, pour préciser plus finement les contenus. La rétro-visualisation dans le texte original des résultats et expressions dégagées éclaire la signification de certains glyphes peu compris, en les situant dans des contextes clairement interprétables

Les protéines FXYD : nouveaux régulateurs de la Na,K-ATPase

Les protéines FXYD appartiennent à une famille de petites protéines membranaires. Des études récentes suggèrent que six des sept membres de cette famille, FXYD1 (phospholemman), FXYD2 (sous-unité γ de la Na,K-ATPase), FXYD3 (Mat-8), FXYD4 (CHIF), FXYD5 (Ric) et FXYD7, sont des sous-unités auxiliaires de la Na, K-ATPase régulant son activité de manière tissu et isoforme spécifique. Ces résultats soulignent la complexité de la régulation des ions Na+ et K+ par la Na,K-ATPase qui est nécessaire pour assurer les fonctions propres de différents tissus comme la réabsorption du Na+ par le rein, la contraction musculaire et l’excitabilité neuronale. De plus, une mutation dans FXYD2 a été liée à certains cas d’hypomagnésémie, suggérant que des perturbations de la régulation de la Na,K-ATPase par les protéines FXYD seraient impliquées dans des états physiopathologiques. Une meilleure compréhension de ce nouveau mécanisme de régulation de la Na,K-ATPase pourrait nous aider à mieux comprendre son rôle dans les états physiopathologiques. Dans cet article, nous discutons les données les plus récentes sur le rôle des protéines FXYD dans la modulation de la Na, K-ATPase.Members of the FXYD protein family are small membrane proteins which are characterized by an FXYD motif, two conserved glycines and a serine residue. FXYD proteins show a tissue-specific distribution. Recent evidence suggests that 6 out of 7 FXYD proteins, FXYD1 (phospholemman), FXYD2 (γ subunit of Na,K-ATPase), FXYD3 (Mat-8), FXYD4 (CHIF), FXYD5 (Ric) and FXYD7 associate with Na,K-ATPase and modulate its transport properties e.g. its Na+ and/or its K+ affinity in a distinct way. These results highlight the complex regulation of Na+ and K+ transport which is necessary to ensure proper tissue functions such as renal Na+-reabsorption, muscle contractility and neuronal excitability. Moreover, mutation of a conserved glycine residue into an arginine residue in FXYD2 has been linked to cases of human hypomagnesemia indicating that dysregulation of Na,K-ATPase by FXYD proteins may be implicated in pathophysiological states. A better characterization of this novel regulatory mechanism of Na,K-ATPase may help to better understand its role in physiological and pathophysiological conditions

Processing a Mayan Corpus for Enhancing our Knowledge of Ancient Scripts

International audienceThe ancient Maya writing comprises more than 500 signs, either syllabic or semantic, and is largely deciphered, with a variable degree of reliability. We applied to the Dresden Codex, one of the only three manuscripts that reached us, encoded for LATEX with the mayaTEX package, our graded representation method of hybrid non-supervised learning, intermediate between clustering and oblique factor analysis, and following Hellinger metrics, in order to obtain a nuanced image of themes dealt with: the statistical entities are the 214 codex segments, and their attributes are the 1687 extracted bigrams of signs. For comparison, we introduced in this approach an exogenous element, i.e. the splitting of the composed signs into their elements, for a finer elicitation of the contents. The results are visualized as a set of "thematic concordances": for each homogeneous semantic context, the most salient bigrams or sequences of bigrams are displayed in their textual environment, which sheds a new light on the meaning of some little understood glyphs, placing them in clearly understandable contexts

A human coronavirus responsible for the common cold massively kills dendritic cells but not monocytes

Copyright @ 2012, American Society for Microbiology.Human coronaviruses are associated with upper respiratory tract infections that occasionally spread to the lungs and other organs. Although airway epithelial cells represent an important target for infection, the respiratory epithelium is also composed of an elaborate network of dendritic cells (DCs) that are essential sentinels of the immune system, sensing pathogens and presenting foreign antigens to T lymphocytes. In this report, we show that in vitro infection by human coronavirus 229E (HCoV-229E) induces massive cytopathic effects in DCs, including the formation of large syncytia and cell death within only few hours. In contrast, monocytes are much more resistant to infection and cytopathic effects despite similar expression levels of CD13, the membrane receptor for HCoV-229E. While the differentiation of monocytes into DCs in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4 requires 5 days, only 24 h are sufficient for these cytokines to sensitize monocytes to cell death and cytopathic effects when infected by HCoV-229E. Cell death induced by HCoV-229E is independent of TRAIL, FasL, tumor necrosis factor alpha, and caspase activity, indicating that viral replication is directly responsible for the observed cytopathic effects. The consequence of DC death at the early stage of HCoV-229E infection may have an impact on the early control of viral dissemination and on the establishment of long-lasting immune memory, since people can be reinfected multiple times by HCoV-229E

Asymptotic wavelet and Gabor analysis: extraction of instantaneous frequencies

International audienceWe investigate the behaviour of the continuous wavelet and Gabor coefficients in the asymptotic limit, using stationary phase approximations. In particular, we show how, under some additional assumptions, these coefficients allow the extraction of some characteristics of the analysed signal, like for example frequency and amplitude modulation laws. We also briefly discuss applications to spectral lines estimations and matched filtering

Tmprss3 loss of function impairs cochlear inner hair cell Kcnma1 channel membrane expression

Before acquiring their mature state, cochlear hair cells undergo a series of changes in expression of ion channels. How this complex mechanism is achieved is not fully understood. Tmprss3, a type II serine protease expressed in hair cells, is required for their proper functioning at the onset of hearing. To unravel the role of Tmprss3 in the acquisition of mature K+ currents, we compared their function by patch-clamp technique in wild-type Tmprss3WT and Tmprss3Y260X-mutant mice. Interestingly, only outward K+ currents were altered in Tmprss3Y260X-mutant mice. To determine by which mechanism this occurred, we compared the protein network of Tmprss3WT and Tmprss3Y260X-mutant mice using proteomic analysis. This led to the identification of a pathway related to potassium Kcnma1 channels. This pathway was validated by immunohistochemistry, focusing on the most downregulated protein that was identified as a cochlear Kcnma1-associated protein, APOA1. Finally, we show that, in contrast to Tmprss3WT, Kcnma1 channels were absent at the neck of inner hair cells (IHCs) in Tmprss3Y260X-mutant mice. In conclusion, our data suggest that lack of Tmprss3 leads to a decrease in Kcnma1 potassium channels expression in (IHCs

The Pole Behaviour of the Phase Derivative of the Short-Time Fourier Transform

The short-time Fourier transform (STFT) is a time-frequency representation widely used in applications, for example in audio signal processing. Recently it has been shown that not only the amplitude, but also the phase of this representation can be successfully exploited for improved analysis and processing. In this paper we describe a rather peculiar pole phenomenon in the phase derivative, a recurring pattern that appears in a characteristic way in the neighborhood around any of the zeros of the STFT, a negative peak followed by a positive one. We describe this phenomenon numerically and provide a complete analytical explanation.Comment: 15 pages, 4 figures; Applied and Computational Harmonic Analysis (in press), available online 22 October 201

Molecular analysis of the TMPRSS3 gene in Moroccan families with non-syndromic hearing loss

Autosomal recessive non-syndromic hearing impairment (ARNSHI) is the most common type of inherited hearing impairment, accounting for approximately 80% of inherited prelingual hearing impairment. Hearing loss is noted to be both phenotypically and genetically heterogeneous. Mutations in the TMPRSS3 gene, which encodes a transmembrane serine protease, are known to cause autosomal recessive non-syndromic hearing impairment DFNB8/10. In order to elucidate if the TMPRSS3 gene is responsible for ARNSHI in 80 Moroccan families with non-syndromic hearing impairment, the gene was sequenced using DNA samples from these families. Nineteen TMPRSS3 variants were found, nine are located in the exons among which six are missense and three are synonymous. The 10 remaining variations are located in non-coding regions. Missense variants analysis show that they do not have a significant pathogenic effect on protein while pathogenicity of some variant remains under discussion. Thus we show that the TMPRSS3 gene is not a major contributor to non-syndromic deafness in the Moroccan population