Developing an Index to Measure Sub-municipal Level Urban Sprawl

The present study aims to develop an index composed of different spatial variables to measure the urban sprawl levels of a municipality located in Southern Spain. According to the findings, urban sprawl can be measured not only on the metropolitan level but also on a more detailed and precise level, such as sub-municipal. A group of experts chosen for their suitability in measuring urban sprawl select six spatial variables (population density, net residential density, coverage ratio, land use types, percentage of residential land use, and average year of construction). These variables are aggregated using Choquet integral, a technique that combines interactions between those variables providing greater coherence to the complexity that is inherent in the creation of composite sprawl indexes. This methodology has been demonstrated to be valid and appropriate in evaluating urban expansion at sub-municipal level, but can also be applied to other scales once it is clearly a phenomenon in which interaction between criteria exists. The resulting composite index allows the assignment of different levels of sprawl to the urban areas consistent with their morphology and landscape.     

Applying the Consensual Method of Estimating Poverty in a Low Income African Setting

Social Indicators Research - We present the first study of multidimensional poverty in Benin using the consensual or socially perceived necessities approach. There is a remarkable level consensus...     

Model-based clustering of multivariate skew data with circular components and missing values

Motivated by classification issues that arise in marine studies, we propose a latent-class mixture model for the unsupervised classification of incomplete quadrivariate data with two linear and two circular components. The model integrates bivariate circular densities and bivariate skew normal densities to capture the association between toroidal clusters of bivariate circular observations and planar clusters of bivariate linear observations. Maximum-likelihood estimation of the model is facilitated by an expectation maximization (EM) algorithm that treats unknown class membership and missing values as different sources of incomplete information. The model is exploited on hourly observations of wind speed and direction and wave height and direction to identify a number of sea regimes, which represent specific distributional shapes that the data take under environmental latent conditions.     

Bayesian analysis of elapsed times in continuous‐time Markov chains

The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software.     

Re-randomization tests as sensitivity analyses to confirm immunological noninferiority of an investigational vaccine: Case study

Here we present as case study how re-randomization tests were performed in two randomized, controlled clinical trials as sensitivity analyses, as recommended by the United States Food and Drug Administration in the context of adaptive randomization. This was done to confirm primary conclusions on immunological noninferiority of an investigational new fully liquid presentation of a quadrivalent cross-reacting material conjugate meningococcal vaccine (MenACWY-CRM), over its licensed lyophilized/liquid presentation. In two phase 2b studies (Study #1: NCT03652610; Study #2: NCT03433482), noninferiority of the fully liquid presentation of MenACWY-CRM to the licensed presentation was assessed and demonstrated for immune responses against meningococcal serogroup A (MenA), the only vaccine component modified from lyophilized to liquid in the new presentation. The original vaccine assignment algorithm, with a minimization procedure accounting for center or center within age strata, was used to re-randomize participants belonging to the fully liquid and licensed vaccine groups while keeping antibody responses, covariates and entry order as observed. Test statistics under re-randomization were generated according to the ANCOVA model used in the primary analysis. To confirm immunological noninferiority following re-randomization, the corresponding p-values had to be <0.025. For both studies and all primary objective evaluations, the re-randomization p-values were well below 0.025 (0.0004 for Study #1; 0.0001 for the two co-primary endpoints in Study #2). Re-randomization tests performed to comply with a regulatory request confirmed the primary conclusions of immunological noninferiority for the MenA of the fully liquid compared to the licensed vaccine presentation.     

The determinants of transnational entrepreneurship and transnational ties’ dynamics among immigrant entrepreneurs in ICT sector in Italy

This article contributes to the rapidly growing literature on transnational immigrant entrepreneurship by analyzing the determinants of transnational entrepreneurial engagement among immigrants in the ICT sector in Italy. We investigate which factors influence the rise or decline of transnational entrepreneurial involvement with a home country. Our results indicate that longer residence in Italy is associated with smaller propensity to become a transnational entrepreneur. Moreover, we find that the type of transnational ties and the network size have a substantial impact on the dynamics of transnational entrepreneurial engagement.     

The policies of unemployment protection in Europe

The abundant literature on welfare state policies, regimes or ‘worlds’ has been only limitedly interested in unemployment protection, and even less in youth unemployment protection. What is clearly lacking in the literature is an updated analysis of the most recent policies developed in European countries targeting youth. This mini‐symposium aims to fill in this gap by presenting findings from an EU‐funded research project entitled ‘Youth, Unemployment and Exclusion in Europe: A Multidimensional Approach to Understanding the Conditions and Prospects for Social and Political Integration of Young Unemployed’ (YOUNEX). The main aim of the research endeavour was to develop theory and contribute to empirical knowledge concerning the social and political exclusion of unemployed youth in Europe.     

Maximal symmetry and the Nash solution

The Nash Bargaining Solution is characterised by using the new axiom of Maximal Symmetry in place of Nash's Independence of Irrelevant Alternatives and Symmetry. This axiom expresses the idea that a fair arbitrator should treat symmetric alternatives in the same way, subject to the feasibility constraint. An advantage of the proposed characterisations is that they are valid on a wide set of domains, in particular domains including, or consisting of, non-convex problems. Received: 16 March 1998/Accepted: 13 October 1998