Comments on the Chern-Simons photon term in the QED description of graphene

We revisit the Coleman-Hill theorem in the context of reduced planar QED. Using the global U(1) Ward identity for this non-local but still gauge invariant theory, we can confirm that the topological piece of the photon self-energy at zero momentum does not receive further quantum corrections apart from the potential one-loop contribution, even when considering the Lorentz non-invariant case due to the Fermi velocity $v_F<c$. This is of relevance to probe possible time parity odd dynamics in a planar sheet of graphene which has an effective description in terms of $(2+1)$-dimensional planar reduced QED.Comment: New section added, published versio

Time-Delayed transfer functions simulations for LMXBs

Recent works (Steeghs & Casares 2002, Casares et al. 2003, Hynes et al. 2003) have demonstrated that Bowen flourescence is a very efficient tracer of the companion star in LMXBs. We present a numerical code to simulate time-delayed transfer functions in LMXBs, specific to the case of reprocessing in emission lines. The code is also able to obtain geometrical and binary parameters by fitting observed (X-ray + optical) light curves using simulated annealing methods. In this work we present the geometrical model for the companion star and the analytical model for the disc and show synthetic time-delay transfer functions for different orbital phases and system parameters.Comment: Contribution presented at the conference "Interacting Binaries: Accretion, Evolution and Outcomes", held in Cefalu, Sicily (Italy) in July 2004. To be published by AIP (American Institute of Physics), eds. L. A. Antonelli, L. Burderi, F. D'Antona, T. Di Salvo, G.L. Israel, L. Piersanti, O. Straniero, A. Tornambe. 4 pages, 4 figure

On Gale and Shapley ‘College admissions and stability of marriage’

In this note, we start to claim that established marriages can be heavily destabilized when the population of existing couples is enriched by the arrival of new candidates to marriage. Afterwards, we discuss briefly how stability concepts can be extended to account for entry and exit phenomena affecting the composition of the marriage market.Matching; stability; marriage model; divorce cascades

A Ocupação Dispersa, à escala local, nas Cidades de Aveiro-Ílhavo e Évora: identificação e caracterização

Este trabalho insere-se no Projecto “Custos e Benefícios, à escala local, de uma Ocupação Dispersa” , desenvolvido pelas universidades de Aveiro e Évora, em parceria com a DGOTDU, e contém a descrição da Metodologia adoptada para delimitar e caracterizar a Ocupação Dispersa à escala local, e a análise comparativa dos resultados da sua aplicação a duas cidades: Aveiro-Ílhavo e Évora

A Methodology for identifying and characterizing local scale territorial units, within the extended city

This communication intends to summarily present a Methodology for identifying and characterizing local scale territorial units within the Extended City designed during the ongoing research project Costs and Benefits of Urban Dispersion on a Local Scale

Methodology to identify dispersed occupation on a local scale

The study of urban dispersion on a local scale requires the adoption of operational concepts. This research uses the notion of "Base Land Unit" (BLU), which represents a functional and experiential reality. The current paper presents an explanation of this concept and a methodology to distinguish BLU of dispersed occupation from other types of Units (concentrated, unbuilt…). The developed methodology comprises three different methods: - Identification of Building Ensembles by Digital Method; - Calculation of the Disaggregation Index of Continuous Building Ensembles; - Criterion for Identifying BLU of Dispersed Occupation. A detailed description of each phase is presented, as well as the results of its application in the case studies of the Research Project (Évora and Aveiro-Ílhavo)