Extinction probabilities of branching processes with countably infinitely many types

We present two iterative methods for computing the global and partial extinction probability vectors for Galton-Watson processes with countably infinitely many types. The probabilistic interpretation of these methods involves truncated Galton-Watson processes with finite sets of types and modified progeny generating functions. In addition, we discuss the connection of the convergence norm of the mean progeny matrix with extinction criteria. Finally, we give a sufficient condition for a population to become extinct almost surely even though its population size explodes on the average, which is impossible in a branching process with finitely many types. We conclude with some numerical illustrations for our algorithmic methods

L'influence de la langue maternelle sur les capacités de l'auditeur dans la perception de la parole

Les études en psycholinguistique et en neurosciences cognitives ont permis de grandes avancées quant à la compréhension des mécanismes impliqués dans la perception des sons de parole. Nous présentons une revue sélective que nous espérons représentative des recherches sur la perception de la parole. Plus particulièrement, les recherches présentées montrent que notre système perceptif se façonne dès la première année de vie, de manière à exploiter finement les régularités phonologiques de notre langue maternelle. En conséquence, notre système de perception de la parole est mal adapté pour l'écoute de langues ne respectant pas les contraintes phonologiques de la langue maternelle, nous rendant ainsi sourd à des contrastes, non discriminatifs dans notre propre langue

Un changement de voix affecte t-il le processus de reconnaissance des mots parlés?

International audienceAccording to McLennan and Luce [1], variability in talker identity affects spoken word recognition when processing is slow and effortful. In the present study, we tested this hypothesis by manipulating the neighbourhood density of target words in a repetition priming experiment. Both for words with few and many phonological neighbours, the amount of priming for repeated words was not affected by a voice change. Such observation supports the claim that abstract representations exist and underlie spoken word recognition.Dans cette étude, nous avons examiné l'impact d'un changement de voix sur le processus de reconnaissance des mots parlés

How much imitation is there in a shadowing task?

International audiencePhonetic imitation, also called phonetic convergence, is currently at the heart of numerous investigations since it can inform us on both the nature of lexical representations and the link between production and perception processes in spoken language communication. A task that has been largely used to study phonetic imitation is the shadowing task, in which participants merely listen to and repeat isolated words. In this study, we examined the extent to which the phonetic convergence effect found when participants shadow auditory tokens, is an imitation of the speaker. We thus compared the phonetic convergence effect observed in a shadowing task to that observed when participants were explicitly instructed to imitate the productions they were exposed to. Although the phonetic convergence effect was greater when participants intentionally imitated the speaker's productions, shadowing and imitation instructions led to the same degree of convergence in a post-exposure task. Hence, the convergence effect found in a shadowing task and that found in an imitation task seem to share a general mechanism which is automatic and which taps into the long-term representations of the words in memory. At a more theoretical level, our results reinforce the claim that detailed auditory traces associated with perceived words are stored in memory and are later used for production

Funding Constraints and Market Illiquidity in the European Treasury Bond Market

Theoretical studies show that shocks to funding constraints should affect and be affected by market illiquidity. However, little is known about the empirical magnitude of such responses because of the intrinsic endogeneity of illiquidity shocks. This paper adopts an identification technique based on the heteroskedasticity of illiquidity proxies to infer the reaction of one measure to shocks affecting the other. Using data for the European Treasury bond market, we find evidence that funding illiquidity shocks affect bond market illiquidity and of a weaker simultaneous feedback reverse. We also investigate the determinants of the magnitude of these effects in the cross-section of bonds and find that the responses of individual bonds' market illiquidity to funding illiquidity shocks increase with bond duration, with the credit risk of the issuer, and with haircuts

Funding Constraints and Market Illiquidity in the European Treasury Bond Market

Theoretical studies show that shocks to funding constraints should affect and be affected by market illiquidity. However, little is known about the empirical magnitude of such responses because of the intrinsic endogeneity of illiquidity shocks. This paper adopts an identification technique based on the heteroskedasticity of illiquidity proxies to infer the reaction of one measure to shocks affecting the other. Using data for the European Treasury bond market, we find evidence that funding illiquidity shocks affect bond market illiquidity and of a weaker simultaneous feedback reverse. We also investigate the determinants of the magnitude of these effects in the cross-section of bonds and find that the responses of individual bonds' market illiquidity to funding illiquidity shocks increase with bond duration, with the credit risk of the issuer, and with haircuts

A patient with anti-NXP2-positive dermatomyositis and syphilis

Dermatomyositis is an auto-immune inflammatory myopathy that primarily affects the skin and muscle and can be triggered by exposure to various environmental factors. We present a patient with active syphilis infection who developed dermatomyositis and discuss the significance of anti-NXP2 autoantibody positivity

Young Children in Deep Poverty: Racial/Ethnic Disparities and Child Well-Being Compared to Other Income Groups

This report compares early health, development, and risk indicators for young children in deep poverty to indicators for young children in other income groups. The results show that young children in deep poverty experience exceptional challenges that make them vulnerable to poor long-term outcomes. The report also highlights large disparities in the prevalence of deep poverty across five racial/ethnic groups, nationally and state by state.https://educate.bankstreet.edu/gse/1005/thumbnail.jp