Rafael Hurtado

Rich do not rise early: Spatio-temporal patterns in the mobility networks of different socio-economic classes

We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is represented by six mobility networks, each one encoding the origin-destination trips performed by a subset of the population corresponding to a particular socio-economic status. The nodes of each network are the different urban locations whereas links account for the existence of a trip between two different areas of the city. We study the main structural properties of these mobility networks by focusing on their spatio-temporal patterns. Our goal is to relate these patterns with the partition into six socio-economic compartments of these two societies. Our results show that spatial and temporal patterns vary across these socio-economic groups. In particular, the two datasets show that as wealth increases the early-morning activity is delayed, the midday peak becomes smoother and the spatial distribution of trips becomes more localized.

Several Multiplexes in the same City: The role of wealth differences in urban mobility

In this paper, we take a critical perspective on the common regulatory reply to deal with call termination on mobile networks. The current policy tendency to deal with fixed-to-mobile call termination is to restrict attention to the defined relevant market (call termination on single networks is the usual outcome), establish substantial market power, and regulate the prices in question. This approach is understandable within the context of the regulatory framework in the EU, but it ignores important elements of the broader picture and therefore risks to be misguided from a welfare viewpoint. Compared to price controls, there exist alternative, less heavy-handed, ways to intervene, which are directly aiming at the root cause of the problem and can make access regulation unnecessary. For instance, inducing mobile operators to apply RPP instead of CPP is a straightforward and simple remedy, as it instantaneously eliminates the root cause of call termination monopolies.

Several Multiplexes in the Same City: The Role of Socioeconomic Differences in Urban Mobility

In this work we analyze the architecture of real urban mobility networks from the multiplex perspective. In particular, based on empirical data about the mobility patterns in the cities of Bogota and Medellin, each city is represented by six multiplex networks, each one representing the origin-destination trips performed by a subset of the population corresponding to a particular socioeconomic status. The nodes of each multiplex are the different urban locations whereas links represent the existence of a trip from one node (origin) to another (destination). On the other hand, the different layers of each multiplex correspond to the different existing transportation modes. By exploiting the characterization of multiplex transportation networks combining different transportation modes, we aim at characterizing the mobility patterns of each subset of the population. Our results show that the socioeconomic characteristics of the population have an extraordinary impact in the layer organization of these multiplex systems.

Tiempos de escritura en numerales de tres dígitos: relación entre el tiempo y la estructura sintáctica de las expresiones verbales dictadas

Objetivo. El presente estudio evalua el ajuste de los tiempos en las pausas entre digitos, en la escritura de numerales arabigos, con las predicciones que se derivan de los modelos de transcodificacion de Power y Dal Martello (1990) y Barrouillet, Camos, Perruchet y Seron (2004), quienes explican el proceso de transcodificacion de numerales en ninos. Metodo. En el estudio participaron 25 ninos de primer grado que escribian correctamente numerales de tres digitos a partir de un dictado, se analizo el tiempo de las pausas entre digitos para cuatro tipos de numeral en cuatro sesiones de trabajo. Resultados. Los analisis de varianza ANOVA mostraron que en los cuatro tipos de numerales la duracion en la primera pausa es mayor que en la segunda y que los menores tiempos tienen lugar antes de escribir el digito cero. Conclusion. Estos resultados se ajustan mejor a las predicciones basadas en el modelo de Barrouliet et al. (2004), el cual supone que la cadena de digitos se produce y almacena en una memoria intermedia para luego ser producida por los procedimientos de grafomotores, lo que sugiere que en los numerales de tres digitos los tiempos en las pausas entre digitos reflejan el programa motor de escritura mas que la estructura sintactica de los numerales verbales dictados.

Higgs Boson Decay in the Large N Limit

The Equivalence Theorem is commonly used to calculate perturbatively amplitudes involving gauge bosons at energy scales higher than gauge boson masses. However, when the scalar sector is strongly interacting the theory is non-perturbative. We show that the Equivalence Theorem holds in the large N limit at next-to-leading order by calculating the decay widths h ® W+W- and h ® p+p-. We also show, in the same scheme of calculations, that unitarity is fulfilled for the process h ® p+p-.