Evidence for a 304-day Orbital Period for GX 1+4

In this paper we report strong evidence for a ~304-day periodicity in the spin history of the accretion-powered pulsar GX 1+4 that is very likely to be a signature of the orbital period of the system. Using BATSE public-domain data, we show a highly-significant periodic modulation of the pulsar frequency from 1991 to date which is in excellent agreement with the ephemeris proposed by Cutler, Dennis & Dolan in 1986, which were based on a few events of enhanced spin-up that occurred during the pulsar's spin-up era in the 1970s. Our results indicate that the orbital period of GX 1+4 is 303.8+-1.1 days, making it by far the widest low-mass X-ray binary system known. A likely scenario for this system is an elliptical orbit in which the neutron star decreases its spin-down rate (or even exhibits a momentary spin-up behavior) at periastron passages due to the higher torque exerted by the accretion disk onto the magnetosphere of the neutron star.Comment: 5 pages, 2 figures, 1 single PS file, to appear in "Proceedings of the 5th Compton Symposium on Gamma-Ray Astrophysics", AI

Symmetry Constrained Two Higgs Doublet Models

We study Two-Higgs-Doublet Models (2HDM) where Abelian symmetries have been introduced, leading to a drastic reduction in the number of free parameters in the 2HDM. Our analysis is inspired in BGL models, where, as the result of a symmetry of the Lagrangian, there are tree-level scalar mediated Flavour-Changing-Neutral-Currents, with the flavour structure depending only on the CKM matrix. A systematic analysis is done on the various possible schemes, which are classified in different classes, depending on the way the extra symmetries constrain the matrices of couplings defining the flavour structure of the scalar mediated neutral currents. All the resulting flavour textures of the Yukawa couplings are stable under renormalisation since they result from symmetries imposed at the Lagrangian level. We also present a brief phenomenological analysis of the most salient features of each class of symmetry constrained 2HDM.Comment: 30 pages, 5 Table

Understanding the EU Urban Agenda from the margins of Europe: the case of Porto

This research focuses on the EU regional policy and presents a critical analysis of its influence on the urban regeneration process of the Portuguese city of Porto. A particular attention is drawn to the historic centre area which in 1996 was formally recognised by the UNESCO as a World Heritage Site. The old town's social, cultural and historic heritage has been dealing with a diverse range of challenges and consequently has been the stage of different urban interventions. Among the actions that have been implemented during the last 50 years to steer the area's development, two area-based interventions linked to the EU Cohesion Policy have notably contributed to the processes of urban change—1990 Urban Pilot Project and 2006 Programa de Reabilitação Urbana. In order to make sense of the intricate relationship between the urban dimension of the EU regional policy and the processes of urban regeneration we started by tracing the development of the EU urban agenda. As a second step we contextualised the historic Bairro da Sé do Porto area within national and local urban policies and development patterns. Finally, it was possible to put forward a series of considerations regarding the influence of EU initiatives in this southwestern European city. Hopefully, the insights resulting from this research will not only help to understand local effects of EU instruments and their specificities at the level of implementation, but allow future EU policy making to capitalise on its urban agenda in order to promote a better future

GOVERNMENT REVENUES AND EXPENDITURES IN GUINEA-BISSAU: CAUSALITY AND COINTEGRATION

The paper establishes empirically the temporal causality and long run relationship between government expenditures and government revenues for the case of Guinea-Bissau - a low income country under stress (LICUS) in Africa. A macroeconomic model is developed to lay out the hypothesis of a spend-tax behavior in the country¡¯s public finances management system. Empirical validation is carried out by means of a traditional Granger-causality test and the estimation of an error correction model between expenditures and revenues.Public Finances, Causality Tests, Cointegration Analysis

The Context of the Teaching Methods of Full Communicative Competence in English of the 11th Grade Teachers of the Middle Technical - Vocational Institutes in the Province of Cabinda (Angola)

The objective of this article is to analyse the context of teaching methods of English as a foreign language of English teachers of 11th grade of the Middle Technical - Vocational Institutes of Cabinda (Angola). This work consists of understanding why students do not learn full communicative competence in English, the reasons why students study this subject for two years in tenth and eleventh grade at school and three years in seventh to ninth grade but do not speak, do not read and cant even understand a simple request. They finish their studies without acquiring necessary linguistic competence in English. However, it is known that the role of the teacher is to guide the students to build their knowledge to orient their social lives. The results of the research show that teachers mostly use grammar translation methods, and they dont use other pedagogical resources such as publicity posters which would help students to acquire the necessary linguistic communicative competences.</jats:p