Interaction between Public Transportation and Urbanization in the Mexico City Metropolitan Area: an Expansive Model Reaching its Limits

In Metropolitan Area of Mexico City, most of urban displacements happen through semi formal public transportation: small and medium capacity vehicles operated by small private enterprises, through a concession scheme. This kind of public transportation has been playing a major role in the Mexican capital. On one hand, it has been one of the conditions for urbanization to be possible. On the other hand, despite its uncountable deficiencies, public transportation has allowed for a long time the whole population to be able to move within this huge metropolis. However, that important function with regards to integration has now reached its limits in the most recent suburbs of the city, where a new mode of urbanization is taking place, based on massive production of very big social housing gated settlements. Public transportation tends to constitute here a factor of exclusion and households meet with important difficulties for their daily mobility. 

Using non-homogeneous Poisson models with multiple change-points to estimate the number of ozone exceedances in Mexico City

In this paper, we consider some non-homogeneous Poisson models to estimate the probability that an air quality standard is exceeded a given number of times in a time interval of interest. We assume that the number of exceedances occurs according to a non-homogeneous Poisson process (NHPP). This Poisson process has rate function lambda(t), t >= 0, which depends on some parameters that must be estimated. We take into account two cases of rate functions: the Weibull and the Goel-Okumoto. We consider models with and without change-points. When the presence of change-points is assumed, we may have the presence of either one, two or three change-points, depending of the data set. The parameters of the rate functions are estimated using a Gibbs sampling algorithm. Results are applied to ozone data provided by the Mexico City monitoring network. In a first instance, we assume that there are no change-points present. Depending on the adjustment of the model, we assume the presence of either one, two or three change-points. Copyright (C) 2009 John Wiley & Sons, Ltd.

Estimating the number of ozone peaks in Mexico City using a non-homogeneous Poisson model

In this paper, we consider the problem of estimating the number of times an air quality standard is exceeded in a given period of time. A non-homogeneous Poisson model is proposed to analyse this issue. The rate at which the Poisson events occur is given by a rate function lambda(t), t >= 0. This rate function also depends on some parameters that need to be estimated. Two forms of lambda(t), t >= 0 are considered. One of them is of the Weibull form and the other is of the exponentiated-Weibull form. The parameters estimation is made using a Bayesian formulation based on the Gibbs sampling algorithm. The assignation of the prior distributions for the parameters is made in two stages. In the first stage, non-informative prior distributions are considered. Using the information provided by the first stage, more informative prior distributions are used in the second one. The theoretical development is applied to data provided by the monitoring network of Mexico City. The rate function that best fit the data varies according to the region of the city and/or threshold that is considered. In some cases the best fit is the Weibull form and in other cases the best option is the exponentiated-Weibull. Copyright (C) 2007 John Wiley & Sons, Ltd.

Using stochastic volatility models to analyse weekly ozone averages in Mexico City

In this paper we make use of some stochastic volatility models to analyse the behaviour of a weekly ozone average measurements series. The models considered here have been used previously in problems related to financial time series. Two models are considered and their parameters are estimated using a Bayesian approach based on Markov chain Monte Carlo (MCMC) methods. Both models are applied to the data provided by the monitoring network of the Metropolitan Area of Mexico City. The selection of the best model for that specific data set is performed using the Deviance Information Criterion and the Conditional Predictive Ordinate method.

The influence of urban structures on entrepreneurial decision-making: a comparative analysis of Mexico City and São Paulo

Promover a atividade empreendedora é hoje mais do que nunca uma prioridade para as economias em desenvolvimento. Em diferentes partes do mundo, empreendedores têm sido reconhecidos como verdadeiros agentes de transformação, e as novas empresas que eles criam tornam-se condutoras de inovação, que ao final pode ser difundida ao resto da economia. Teorias de economia urbana, que analisam a dinâmica da relação entre aglomeração urbana e atividade econômica, enfatizam a importância da concentração espacial das indústrias num mesmo setor industrial. Entender os incentivos que dão início à atividade empreendedora é algo novo e o foco desses estudos tem sido principalmente em alguns poucos casos de economias industrializadas. Não obstante, o sucesso de um punhado de clusters de alta tecnologia, como o Vale do Silício, por exemplo, na Califórnia, Estados Unidos, não pode ser replicado, e as condições locais devem ser consideradas a fim de entender a surgimento desses ecossistemas. Este estudo pretende investigar os critérios em que os empreendedores fundamentam suas decisões quando selecionam as localizações do seu negócio. Especificamente, a pesquisa explora o recente movimento dos ecossistemas de empreendedores na Cidade do México e em São Paulo, as duas maiores áreas metropolitanas da América Latina, à luz das teorias de economia urbana. A fim de chegar aos resultados, a pesquisa segue o método baseado sobre uma análise comparativa de estudo de casos em dois bairros: Vila Leopoldina em São Paulo e a Colônia Roma Norte na Cidade do México. Os resultados consolidados baseados em entrevistas qualitativas realizadas nos dois bairros revelam que o lugar/sitio urbano, definido em termos de laços locais assim como da atmosfera geral do ambiente, continua sendo importante para os atores apesar das comunicações de alta velocidade que produzem mais interações entre as regiões do mundo. Além disso, a relação entre o empreendedor e o seu entorno é altamente dependente do estágio de desenvolvimento e da natureza da atividade da empresa; redes informais revelam-se essenciais para identificar as oportunidades de negócio antes de serem progressivamente substituídas por relações instituídas com fundos de capital de risco ou incubadoras. Estes dois ecossistemas nascentes geram suas próprias características, o que já pode sugerir suas futuras evoluções.

Citizen awareness and air pollution: the case of Mexico City

Includes bibliography

Citizen awareness and air pollution in three Latin American cities: São Paulo, Santiago and Mexico City. Comparative analysis

Includes bibliography

Methodology of the project Enhancement of citizen awareness for the formulation of air pollution control policies in three metropolitan areas of Latin America: Mexico City, Santiago and São Paulo

Includes bibliography