Activités tertiaires et hiérarchies urbaines : une évaluation de six méthodes d’analyse

Urban and regional economists are often asked to construct central place models which will properly describe the urban hierarchy (in terms of the service sector) of the region which they are studying. In all such studies, the chief analytical problem is basically one of correctly defining (and measuring) tertiary activity and of correctly weighting the various functions which make up the service sector.In this paper, the authors review six alternative methods for measuring and weighting tertiary functions. The mathematical and conceptual properties of each approach are discussed and evaluated. In the second part of the article, the authors compare the actual results obtained by these alternative methods, using data on the Quebec urban system to test their results. They conclude that no one method is entirely satisfactory, each approach measuring a part of reality. But some methods do nevertheless seem to perform better than others: in this respect, the use of localization coefficient type approach seems generally to give the least biased results

Activités tertiaires et hiérarchies urbaines : une évaluation de six méthodes d’analyse

Urban and regional economists are often asked to construct central place models which will properly describe the urban hierarchy (in terms of the service sector) of the region which they are studying. In all such studies, the chief analytical problem is basically one of correctly defining (and measuring) tertiary activity and of correctly weighting the various functions which make up the service sector.

L’audit de la gouvernance : au service d’une plus grande transparence

Cet article met en lumière les différents enjeux qui font en sorte que l’audit gouvernemental, ou de la gouvernance, pourrait être appelé à revêtir de plus en plus d’importance compte tenu de l’engagement clair pour un gouvernement plus transparent et du vecteur de changement sans précédent que constitue le développement exponentiel des moyens inter- actifs de communication. Il propose une réflexion prospective sur l’évolution de la fonction d’audit gouvernemental dans le contexte d’une plus grande ouverture des gouvernements à la participation et à la collaboration des citoyens.This article highlights the various issues involved in driving a potential greater role for governmental audit or audit of governance. Such drivers include the clear commitment to greater openness on the part of governments and the exponential development of interactive modes of communication. In fact, this text proposes a prospective reflection on the emerging role of governmental audit in the context of greater receptiveness by governments to the participation and collaboration of citizens

Insights on the Interactions of Synthetic Amphipathic Peptides with Model Membranes as Revealed by (31)P and (2)H Solid-State NMR and Infrared Spectroscopies

We studied the interaction between synthetic amphipathic peptides and model membranes by solid-state NMR and infrared spectroscopies. Peptides with 14 and 21 amino acids composed of leucines and phenylalanines modified by the addition of crown ethers were synthesized. The 14-mer and 21-mer peptides both possess a helical amphipathic structure. To shed light on their membrane interaction, (31)P and (2)H solid-state NMR experiments were performed on both peptides in interaction with dimyristoylphosphatidylcholine vesicles in the absence and presence of cholesterol, dimyristoylphosphatidylglycerol vesicles, and oriented bicelles. (31)P NMR experiments on multilamellar vesicles reveal that the dynamics and/or orientation of the polar headgroups are weakly yet markedly affected by the presence of the peptides, whereas (31)P NMR experiments on bicelles indicate no significant changes in the morphology and orientation of the bicelles. On the other hand, (2)H NMR experiments on vesicles reveal that the acyl chain order is affected differently depending on the membrane lipidic composition and on the peptide hydrophobic length. Finally, infrared spectroscopy was used to study the interfacial region of the bilayer. Based on these studies, mechanisms of membrane perturbation are proposed for the 14-mer and 21-mer peptides in interaction with model membranes depending on the bilayer composition and peptide length

Productivity of lexical categories in French-speaking children with cochlear implants. Brain Cogn 2003; 53

Abstract The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing-impaired French-speaking children with cochlear implants. Age of implantation ranged from 22 months to 76 months. Spontaneous speech samples were collected at six-month intervals over a period of 36 months, starting at the one-word stage. Four general measures of their linguistic production (number of utterances, verbal fluency, vocabulary, and grammatical production) as well as 36 specific lexical categories, according to the CHILDES codes, were computed in terms of tokens, i.e., total number of words. Cochlear-implanted children (CI) were compared to a French database of normally hearing children aged 2-4 compiled by the first author. Follow-up results indicate that, at the two-year post-implantation follow-up, noun, and verb morphology was significantly impaired. At the three-year followup, the cochlear-implanted group had recovered on adjectives, determiners and nouns, main verbs, and auxiliaries. The two groups differed significantly in processing locative adverbs, prepositions, pronouns, and verbs (infinitive verb, modal, and modal lexical), but individual variability within the cochlear-implanted group was substantial. Results are discussed in terms of recovery and developmental trends and variability in the acquisition of lexical categories by French children two years and three years post-implantation

Keratin 8 is required for the maintenance of architectural structure in thymus epithelium.

Keratins (Ks), the intermediate filament (IF) proteins of epithelia, are coordinately expressed as pairs in a cell-lineage and differentiation manner. Cortical thymic epithelial cells (cTECs) predominantly express the simple epithelium keratin 8/18 (K8/K18) pair, whereas medullary thymic epithelial cells (mTECs) express the stratified epithelium K5/K14 pair, with TECs exhibiting K5 and K8 at the cortico-medullary junction in mature thymus. In the work reported here, we used wild-type (WT) and K8-knockout (K8-null) mice to address the contribution of K8/K18 IFs in the maintenance of the thymic epithelial structure. K8-null thymus maintained the differential cell segregation at the cortex versus the medulla observed in WT thymus, and the distribution of immature thymocytes at the cortex. The K8/K18 loss did not affect thymocyte development. However, it massively perturbed the TEC morphology both at the cortex and the medulla, along with a prominent depletion of cTECs. Such tissue alterations coincided with an increase in apoptosis and a reduced expression of Albatross (Fas-binding factor-1), also known for its capacity to bind K8/18 IFs. In addition, the K8/K18 loss affected the distribution of K5/K14-positive mTECs, but not their differentiation status. Together, the results indicate that K8/K18 IFs constitute key promoters of the thymic epithelium integrity