Mathematical political districting taking care of minority groups

AbstractPolitical districting (PD) is a wide studied topic in the literature since the 60s. It typically requires a multi-criteria approach, and mathematical programs are frequently suggested to model the many aspects of this difficult problem. This implies that exact models cannot be solved to optimality when the size of the territory is too large. In spite of this, an exact formulation can also be exploited in a heuristic framework to find at least a sub-optimal solution for large size problem instances. We study the design of electoral districts in Mexico, where the population is characterized by the presence of minority groups ("indigenous community") who have a special right to be represented in the Parliament. For this, the Mexican electoral law prescribes that a fixed number of districts must be designed to support the representation of the indigenous community. We formulate mixed integer linear programs (MILP) following these two principles, but also including the basic PD criteria of contiguity and population balance. The district map is obtained in two stages: first we produce the fixed number of indigenous districts established by the Law; then we complete the district map by forming the non-indigenous districts. This two-phase approach has two advantages: a dedicated objective function can be formulated in Phase 1 to form indigenous districts at best; in the second phase the instance size is reduced (both in the number of territorial units and in the number of districts) so that the computational effort to solve the problem is reduced as well. We test our procedure on the territory of Chiapas in Mexico and on some fictitious problem instances in which the territory is represented by a grid graph. We also compare our district map with the Institutional one currently adopted in Chiapas

A New Quota Approach to Electoral Disproportionality

The authors acknowledge and appreciate the comments of two anonymous referees.In this paper electoral disproportionality is split into two types: (1) Forced or unavoidable, due to the very nature of the apportionment problem; and (2) non-forced. While disproportionality indexes proposed in the literature do not distinguish between such components, we design an index, called “quota index”, just measuring avoidable disproportionality. Unlike the previous indexes, the new one can be zero in real situations. Furthermore, this index presents an interesting interpretation concerning transfers of seats. Properties of the quota index and relationships with some usual disproportionality indexes are analyzed. Finally, an empirical approach is undertaken for different countries and elections.We are grateful for the financial support of the Spanish Ministerio de Economía y Competitividad (project ECO2016-77900-P)

Perspectives on the design and use of direct alcohol fuel cells fed by alcohol blends

The fast-growing power demand by portable electronic devices has promoted the increase of global production of portable PEM fuel cell, a quarter of them consist of direct methanol fuel cell (DMFC) units. These present the advantage of being fuelled directly with a liquid fuel, as well as direct ethanol fuel cells (DEFC) do

Matemáticas y política. Fórmulas electorales inaplicables: el sistema electoral de México

Algunos sistemas electorales eligen gran parte de los diputados mediante mayoría simple y asignan los restantes escaños a los partidos políticos de forma que obtengan proporcionalidad global. Alemania ha sido el país pionero en utilizar dicho método de reparto, denominado "mixto", y otros países han tratado, parcialmente, de imitarlo. Así, México elige 300 diputados en distritos uninominales y después distribuye otros 200 escaños a los partidos para corregir grandes desequilibrios respecto a la proporcionalidad. La parte más compleja del sistema electoral de México es cómo distribuir los escaños de representación proporcional que han correspondido a los partidos, entre las 5 circunscripciones, de forma que cada una reciba 40 diputados. Todos los métodos descritos en las leyes electorales de las dos últimas décadas han fallado al intentar resolver este problema. La última reforma fue aprobada en 2014 y se aplicó por primera vez en las elecciones de 2015. Con la actual ley puede resultar necesario negociar entre los partidos para decidir la distribución de algunos escaños. Además, el método Hamilton, que es el usado para redondear las proporciones, junto con las limitaciones establecidas, originaron la paradoja de la abstención. En este trabajo se muestra que ello puede evitarse introduciendo un reparto biproporcional y redondeando con el método Webster

Electrochemical study of platinum deposited by electron beam evaporation for application as fuel cell electrodes

Platinum is the most used catalyst in electrodes for fuel cells due to its high catalytic activity. Polymer electrolyte and direct methanol fuel cells usually include Pt as catalyst in their electrodes. In order to diminish the cost of such electrodes, different Pt deposition methods that permit lowering the metal load whilst maintaining their electroactivity, are being investigated. In this work, the behaviour of electron beam Pt (e-beam Pt) deposited electrodes for fuel cells is studied. Three different Pt loadings have been investigated. The electrochemical behaviour by cyclic voltammetry in H2SO4, HClO4 and in HClO4+MeOH before and after the Pt deposition on carbon cloth has been analysed. The Pt improves the electrochemical properties of the carbon support used. The electrochemical performance of e-beam Pt deposited electrodes was finally studied in a single direct methanol fuel cell (DMFC) and the obtained results indicate that this is a promising and adequate method to prepare fuel cell electrodes

Electrochemical study of platinum deposited by electron beam evaporation for application as fuel cell electrodes

Platinum is the most used catalyst in electrodes for fuel cells due to its high catalytic activity. Polymer electrolyte and direct methanol fuel cells usually include Pt as catalyst in their electrodes. In order to diminish the cost of such electrodes, different Pt deposition methods that permit lowering the metal load whilst maintaining their electroactivity, are being investigated. In this work, the behaviour of electron beam Pt (e-beam Pt) deposited electrodes for fuel cells is studied. Three different Pt loadings have been investigated. The electrochemical behaviour by cyclic voltammetry in H2SO4, HClO4 and in HClO4+MeOH before and after the Pt deposition on carbon cloth has been analysed. The Pt improves the electrochemical properties of the carbon support used. The electrochemical performance of e-beam Pt deposited electrodes was finally studied in a single direct methanol fuel cell (DMFC) and the obtained results indicate that this is a promising and adequate method to prepare fuel cell electrodes

Polipirrol, un buen soporte para electrodos de pilas de combustible de metanol directo (DMFC)

(SPA) El polipirrol es uno de los polímeros conductores más utilizados en la preparación de electrodos debido a su alta actividad catalítica para la oxidación y reducción del metanol. En este trabajo se ha depositado electroquímicamente polipirrol a diferentes potenciales de depósito, Ed, sobre tela de carbón no tejida Freudenberg en medio ácido. Se ha analizado la morfología y la respuesta electroquímica en medio HClO4 y en presencia de HClO4+MeOH antes y después de la síntesis del polipirrol sobre ella. Lastructura de las películas obtenidas se ha estudiado por espectroscopia infrarroja de transformada de Fourier, FTIR. Se observa que el polipirrol mejora las propiedades electroquímicas de la tela de carbón, obteniéndose el mejor resultado para su aplicación como soporte del catalizador en pilas de combustible con la película sintetizada a 1,0V. (ENG) Polypyrrole is one of the most used conducting polymers in electrode building due to its high catalytic activity to the methanol oxidation and reduction. By this motive, polypyrrole has been electrochemically synthesized at constant potential, Ed, on Freudenberg carbon cloth in acid medium. Carbon cloth morphology and electrochemical behaviour in HClO4 and in HClO4+MeOH before and after the polypyrrole eposition have been analysed. The structure of the films was studied by Fourier transform infrared spectroscopy, FTIR. The polypyrrole improves the electrochemical properties of the studied carbon cloth. The biggest charge of the electroactive area is the one synthesized at 1.0V, being the best for its application as catalyst support in fuel cells

Contribution sharing of a fuel mixture components to the fuel cell potencial of a direct alcohol fuel cell

The increasing worldwide demand for electricity impels to develop clean and renewable energy resources. In the field of portable power devices not only size and weight represent important aspects to take into account, but the fuel and its storage are also critical issues to consider. In this last sense, the direct methanol (MeOH) fuel cells (DMFC) play an important role as they can offer high power and energy density, low emissions, ambient operating conditions and fast and convenient refuelling

Estudio clínico del tratamiento de la queratoconjuntivitis seca con ciclosporina A

Se ha realizado un estudio clínico de la aplicación de ciclosporina en colirio al 2% durante dos años y medio, sobre 48 animales afectados de queratoconjuntivitis seca. Los resultados obtenidos se han visto ligados a diferentes factores como son: el valor inicial del test de Schirmer, el estado de la córnea y la etiología y evolución del proceso. En todo caso, su aplicación aumenta la producción de lágrimas de forma significativa y/o proporciona aumento del bienestar ocular por la disminución de la inflamación local, permitiendo eliminar o disminuir la administración concomitante de sustitutos de lágrimas.We have performed a 2 years long clinical study on 2% cyclosporine collyre administration on 48 dogs suffering from keratoconjunctivitis sicca. Results are influenced by several factors, as Schirmer test initial values, corneal status, and the etiology and evolution of the disease. Anyway, 2% cyclosporine collyre administration significantly in creases tear secretion and/or benefits ocular status by reducing local inflamation, thus allowing to diminish or eliminate administration of tear substitutes