Asymptotic Behavior of an Age-Structured Population Model and Optimal Maturation Age

AbstractA continuous age-structured population model with two population groups, juveniles and adults, and with a dynamics for the resource, is considered. The only density dependence is through a uniform increase of the death rates. A complete description of the asymptotic behavior of the population dynamics system is obtained showing under natural hypotheses the existence of a nontrivial (“ecological”) equilibrium which attracts any initial nonzero population with nonzero initial amount of resources. Assuming that the offspring production rate is an increasing function of the maturation age, the evolutionarily stable value of this variable is briefly discussed

Representing number in the real-time processing of agreement: self-paced reading evidence from Arabic

In the processing of subject-verb agreement, non-subject plural nouns following a singular subject sometimes “attract” the agreement with the verb, despite not being grammatically licensed to do so. This phenomenon generates agreement errors in production and an increased tendency to fail to notice such errors in comprehension, thereby providing a window into the representation of grammatical number in working memory during sentence processing. Research in this topic, however, is primarily done in related languages with similar agreement systems. In order to increase the cross-linguistic coverage of the processing of agreement, we conducted a self-paced reading study in Modern Standard Arabic. We report robust agreement attraction errors in relative clauses, a configuration not particularly conducive to the generation of such errors for all possible lexicalizations. In particular, we examined the speed with which readers retrieve a subject controller for both grammatical and ungrammatical agreeing verbs in sentences where verbs are preceded by two NPs, one of which is a local non-subject NP that can act as a distractor for the successful resolution of subject-verb agreement. Our results suggest that the frequency of errors is modulated by the kind of plural formation strategy used on the attractor noun: nouns which form plurals by suffixation condition high rates of attraction, whereas nouns which form their plurals by internal vowel change (ablaut) generate lower rates of errors and reading-time attraction effects of smaller magnitudes. Furthermore, we show some evidence that these agreement attraction effects are mostly contained in the right tail of reaction time distributions. We also present modeling data in the ACT-R framework which supports a view of these ablauting patterns wherein they are differentially specified for number and evaluate the consequences of possible representations for theories of grammar and parsing

Hématome post traumatique du muscle iléopsoas avec paralysie du nerf fémoral: à propos d’un cas et revue de la littérature

L'hématome compressif du muscle iliopsoas dans le petit bassin est une complication connue des traitements anticoagulants, mais reste rare enpost-traumatique. La présente observation illustre un cas de cet hématome chez un adolescent de 14 ans qui s'est présenté avec une douleur  posttraumatique de la cuisse et un déficit actif d'extension de la jambe évoluant depuis plus de 3 mois. Un examen clinique a montré l'existence d'une paralysie complète du quadriceps. Une IRM du petit bassin a retrouvé un volumineux hématome du muscle iliopsoas comprimant le nerf fémoral.Un drainage chirurgical de l'hématome a été réalisé. La récupération  musculaire était partielle après six mois de recul