Multilevel comparison of large urban systems

For the first time the systems of cities in seven countries or regions among the largest in the world (China, India, Brazil, Europe, the Former Soviet Union (FSU), the United States and South Africa) are made comparable through the building of spatio-temporal standardised statistical databases. We first explain the concept of a generic evolutionary urban unit ("city") and its necessary adaptations to the information provided by each national statistical system. Second, the hierarchical structure and the urban growth process are compared at macro-scale for the seven countries with reference to Zipf's and Gibrat's model: in agreement with an evolutionary theory of urban systems, large similarities shape the hierarchical structure and growth processes in BRICS countries as well as in Europe and United States, despite their positions at different stages in the urban transition that explain some structural peculiarities. Third, the individual trajectories of some 10,000 cities are mapped at micro-scale following a cluster analysis of their evolution over the last fifty years. A few common principles extracted from the evolutionary theory of urban systems can explain the diversity of these trajectories, including a specific pattern in their geographical repartition in the Chinese case. We conclude that the observations at macro-level when summarized as stylised facts can help in designing simulation models of urban systems whereas the urban trajectories identified at micro-level are consistent enough for constituting the basis of plausible future population projections.Comment: 14 pages, 9 figures; Pumain, Denise, et al. "Multilevel comparison of large urban systems." Cybergeo: European Journal of Geography (2015

Combinations of single-top-quark production cross-section measurements and vertical bar f(LV)V(tb)vertical bar determinations at root s=7 and 8 TeV with the ATLAS and CMS experiments

This paper presents the combinations of single-top-quark production cross-section measurements by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at = 7 and 8 TeV corresponding to integrated luminosities of 1.17 to 5.1 fb(-1) at = 7 TeV and 12.2 to 20.3 fb(-1) at = 8 TeV. These combinations are performed per centre-of-mass energy and for each production mode: t-channel, tW, and s-channel. The combined t-channel cross-sections are 67.5 +/- 5.7 pb and 87.7 +/- 5.8 pb at = 7 and 8 TeV respectively. The combined tW cross-sections are 16.3 +/- 4.1 pb and 23.1 +/- 3.6 pb at = 7 and 8 TeV respectively. For the s-channel cross-section, the combination yields 4.9 +/- 1.4 pb at = 8 TeV. The square of the magnitude of the CKM matrix element V-tb multiplied by a form factor f(LV) is determined for each production mode and centre-of-mass energy, using the ratio of the measured cross-section to its theoretical prediction. It is assumed that the top-quark-related CKM matrix elements obey the relation |V-td|, |V-ts| << |V-tb|. All the |f(LV)V(tb)|(2) determinations, extracted from individual ratios at = 7 and 8 TeV, are combined, resulting in |f(LV)V(tb)| = 1.02 +/- 0.04 (meas.) +/- 0.02 (theo.). All combined measurements are consistent with their corresponding Standard Model predictions.Peer reviewe

La coévolution du système des villes Brésilien

Cette thèse analyse le système de villes brésilien en se reposant sur une base de données construite en collectant des données démographiques, afin d’étudier l’évolution de la population de l’ensemble des agglomérations brésiliennes depuis le premier recensement de la population en 1872 jusqu’à celui de 2010. Le plus grand pays d’Amérique du Sud, qui a achevé sa transition urbaine lors du siècle dernier, est caractérisé par un contraste majeur entre le grand nombre de petites villes parsemant son territoire immense, et d’immenses aires métropolitaines dominant le système de villes. Des données économiques ont été intégrées à la base de données dans le but de tester la validité des lois d’échelle dans le cas brésilien et effectuer des analyses statistiques robustes afin d’explorer la différenciation fonctionnelle des villes, leur performance économique et le processus d’autocorrélation spatiale qui les caractérisent. Le résultat majeur est la caractérisation de la hiérarchie urbaine brésilienne sur un temps long et la mesure de l’accroissement des inégalités de taille des villes. Par ailleurs, l’intégration de données démographiques et économiques est essentielle à l’identification des imbrications entre population et croissance économiques au sein d’un des pays les plus urbanisés du monde.This thesis analyses the urban system in Brazil adopting an advanced database that have been constructed collecting demographic data in order to examine the evolution of the population of all Brazilian agglomerations since the first Brazilian official census carried out in 1872 until 2010. The largest country of South America has already completed its urban transition during the last century and is characterised by the contrast between a larger number of small towns througout the immense territory and enormous metropolitan areas dominating the system of cities. Despite its georgraphical and historical peculiarities, this system shares with others in the world the same properties of hierarchical differenciation and urban growth processes (Zipf’s law and Gibrat’smodel).Esta tese analisa o sistema urbano do Brasil utilizando um banco de dados avançado que foi construído para examinar a evolução populacional de todas as aglomerações brasileiras, desde o primeiro censo oficial realizado em 1872 até 2010. O maior país da América do Sul completou sua transição urbana no século passado. O sistema urbano é caracterizado por um contraste : Por um lado, há um grande número de pequenas cidades distribuídas em todo o território nacional e, por outro lado, existem algumas metrópoles enormes dominando o sistema de cidades. Apesar das peculiaridades geográficas e históricas, este sistema de cidades compartilha características similares a outros sistemas urbanos no mundo, como a mesma propriedade de diferenciação hierárquica e o processo de crescimento urbano (lei de Zipf e modelo de Gibrat). Os dados econômicos relativos aos diferentes parâmetros foram integrados na base de dados com o objetivo de testar a validade da lei de escala e a análise estatística profunda da realidade do país, a fim de explorar a diferenciação funcional das cidades brasileiras, os seus desempenhos econômicos e os processos de autocorrelação espacial que ocorrem entre elas. O resultado mais interessante investigado foi a caracterização da hierarquia urbana brasileira a longo prazo, medindo o crescimento desigual do tamanho das cidades. Além disso, o suporte paralelo de dados demográfico e econômico é essencial para identificar a conexão entre crescimento populacional e econômico em um dos países mais urbanizado do mundo

The Brazilian Urban System: the trajectories of Brazilian cities between general dynamics and specific peculiarities

This article analyzes the dynamic of Brazilian system of cities illustrating the growth of Brazilian population through its own historical peculiarities like internal and international immigration, industrialization, metropolization. Urban hierarchy is revealed by means of the Zipf’s law and Gibrat’s model is used to describe the mechanisms of urban growth. Deviations from this model were explained by studying the specific trajectories of five different classes of cities, on various time scales (from 1872 to 2010 and from 1960 to 2010). These deviations highlight different kinds of factors (political, economic, localization of resources and historical accidents) that shaped the Brazilian system during the last century

Myogenic effect of SP-1f and SP-1h two novel 3-adrenoceptor (3-AR) agonists in human colonic circular smooth muscle

The effect of two novel 3-adrenoceptor (3-AR) agonists SP-1f and SP-1h on human colon circular smooth muscle contractility and 3-AR mRNA expression have been determined. 3-AR is ascertained co-participates to the control of the gut motility. Isometric tension on human colon muscle strips was measured in response to increasing concentrations of SP-1f, SP-1h and (-)-isoprenaline, alone and in the presence of Betaxolol, ICI 11,855 and SR 59230A (1-, 2- and 3-AR antagonists, respectively). (-)-Isoprenaline concentration-dependently relaxed circular muscle strips with an EC 50=0.32±0.06 μM. Such an effect was antagonized either by the contemporaneously presence of Betaxolol and ICI 11,855 [(-)-isoprenaline EC50=1.75±0.35 μM, pKB=7.88±0.10] or by Betaxolol, ICI 11,855 and SR 59230A [(-)-isoprenaline EC50=3. 49±0.38 μM, pKB=8.51±0.14]. Besides, SP-1f and SP-1h concentration-dependently relaxed circular muscle strips with an EC 50=0.35±0.07 μM and 0.45±0.12 μM, respectively. These values remained unchanged by blocking the 1- and 2-AR. The presence of SR 59230A antagonized the relaxing effect of SP-1f (EC50=3.51±0.94 μM, pKB=8.93±0.16) and did not modify the SP-1h relaxing potency. In colon circular smooth muscle and in mucosa, 3-AR mRNA expression levels were found to be 0.39±0.70 and 0.26±0.12 (P<0.05), respectively. Such results provide further evidence of the 3-adrenoceptor functional role in the human colon and the crucial contribution of SP-1f to the control of the gut dysmotility. © 2013 Elsevier B.V. All rights reserved

Comparación multinivel de grandes sistemas urbanos

For the first time the systems of cities in seven countries or regions among the largest in the world (China, India, Brazil, Europe, the Former Soviet Union (FSU), the United States and South Africa) are made comparable through the building of spatio-temporal standardised statistical databases. We first explain the concept of a generic evolutionary urban unit (“city”) and its necessary adaptations to the information provided by each national statistical system. Second, the hierarchical structure and the urban growth process are compared at macro-scale for the seven countries with reference to Zipf’s and Gibrat’s model: in agreement with an evolutionary theory of urban systems, large similarities shape the hierarchical structure and growth processes in BRICS countries as well as in Europe and United States, despite their positions at different stages in the urban transition that explain some structural peculiarities. Third, the individual trajectories of some 10,000 cities are mapped at micro-scale following a cluster analysis of their evolution over the last fifty years. A few common principles extracted from the evolutionary theory of urban systems can explain the diversity of these trajectories, including a specific pattern in their geographical repartition in the Chinese case. We conclude that the observations at macro-level when summarized as stylised facts can help in designing simulation models of urban systems whereas the urban trajectories identified at micro-level are consistent enough for constituting the basis of plausible future population projections. Keywords: urban system, Zipf's law, Gibrat, cities trajectories, BRIC