Condiciones ambientales y diferenciación social en los patrones de movilidad: el caso de las desigualdades de género en el Área Metropolitana de Lisboa

Place determinants and social dimensions interact to produce mobility patterns. The article seeks to measure to what extent the physical and social conditions of the residency place modulate the intensity of mobility particularly in what concerns gender inequalities. To do so, we first present the theoretical framework, which guides our perspective on mobility inequalities and the geographical focus: Lisbon Metropolitan Area (LMA). Secondly, using logistic regression on representative data from a survey to LMA inhabitants we elaborate on the concept of environmental motility and its relationship to various types of inequality. Lastly, we systematize a view on accumulated inequalities examining how local environments may increase the mobilities gender gap.info:eu-repo/semantics/publishedVersio

Hazard assessment of storm events in the central region of the Portuguese coast

The environmental and socio-economic importance of the coastal areas is widely recognized, but these areas face today severe weaknesses and high-risk situations. The increased demand and human occupation of the coast has greatly contributed to increase such weaknesses. Today, throughout the world, in all countries with coastlines, episodes of waves overtopping and coastal flooding are frequent. These episodes are usually responsible for property losses and often put human lives at risk. The floods are caused by coastal storms due to the action of very strong winds. The propagation of these storms towards the coast induces high water levels. Consequently, carrying out series of storm scenarios and analyzing their impacts through numerical modelling is of prime interest to the coastal decision-makers. A contribution to the preservation and sustainability of the coastal zone constitutes the main aim of this work. Firstly, historical storm tracks and intensities are characterized for the Portuguese coast, in terms of probability of occurrence. Secondly, several storm events with high potential of occurrence are generated using the specific tool DelftDashboard. The hydrodynamic model Delft3D is then used to simulate their effects on currents and on the coastal water levels. Two spatial domains are considered: a large domain encompassing the Iberian coastal zone and a smaller domain for the central region of the Portuguese coast (between cities of Aveiro and Figueira da Foz); this one with a more refined grid. Based on statistical data and by numerical modelling, a review of the impact of coastal storms to different locations within the study area is performed

Magnetovac Cylinder to Magnetovac Torus

A method for mapping known cylindrical magnetovac solutions to solutions in torus coordinates is developed. Identification of the cylinder ends changes topology from R1 x S1 to S1 x S1. An analytic Einstein-Maxwell solution for a toroidal magnetic field in tori is presented. The toroidal interior is matched to an asymptotically flat vacuum exterior, connected by an Israel boundary layer.Comment: to appear in Class. Quant. Gra

Un mito del hambre en el nordeste de Brasil

El objetivo del presente estudio es permitir la comprensión, mediante un abordaje etnográfico, de los significados del hambre en las vivencias de actores sociales que enfrentan la pobreza extrema en un barrio de Salvador, Bahía, Brasil. Los relatos se han analizado con el objeto de entender la construcción de signos inherentes al sufrimiento de quienes padecen de hambre cotidianamente. En la dimensión cultural, este flagelo humano se manifiesta bajo diversas formas (metáforas); una de ellas ilustrada por el caso concreto que aquí se presenta. Se trata de la encarnación de una leyenda del sertão del nordeste de Brasil que da visibilidad al mito del hambre llamado "Romãozinho", el cual, en su configuración mítica, ataca y roba el alimento de los niños del barrio, llevándolos inexorablemente a la muerte. "Romãozinho" es una de las creaciones de la cultura del hambre presente en los sectores populares socialmente excluidos

Interplay between bending and stretching in carbon nanoribbons

We investigate the bending properties of carbon nanoribbons by combining continuum elasticity theory and tight-binding atomistic simulations. First, we develop a complete analysis of a given bended configuration through continuum mechanics. Then, we provide by tight-binding calculations the value of the bending rigidity in good agreement with recent literature. We discuss the emergence of a stretching field induced by the full atomic-scale relaxation of the nanoribbon architecture. We further prove that such an in-plane strain field can be decomposed into a first contribution due to the actual bending of the sheet and a second one due to edge effects.Comment: 5 pages, 6 figure

Contribution to the preservation of healthy coastal ecosystems

The release of pollutants into coastal zones from municipal and/or industrial drainage systems is a problem with a considerable environmental impact. In order to minimize the contamination of coastal waters in certain places (e.g., along beaches and in aquacultures), solutions based on the construction of submarine sewer outfalls have been proposed. In order to ascertain the optimal conditions for the release of an emissary, in particular the place of release, it is necessary to characterize the hydrodynamic transport processes that govern the evolution and mixture of pollutants in the area of interest. Circulation in the coastal zone is complicated, given that it is determined by a set of forcing mechanisms of diverse origins (meteorological, astronomical, large-scale ocean circulation, etc.) that endow it with a considerable space-time variation. Wastewater plume behaviour and characteristics depend both on the receiving water conditions and on the discharge characteristics. Accordingly, the implementation of a submarine outfall system requires a prior study of the site where the outfall is to be constructed, in order to achieve optimal rates of dilution of the pollutants released to the environment. Mathematical modelling appears to be a very useful tool for coastal zone environmental management either for continuous monitoring analysis or in accidental ecosystem rupture. This work presents some results and conclusions of two case studies. The first is a study of the pollutant cloud released at the São Jacinto submarine sewer outfall, located about 3 km offshore and 3 km north of an important coastal lagoon (NW Portugal). The main focus of this study was to establish the hydrodynamic conditions in which the pollutant release might affect the coastline (principally the existing beaches and lagoon). The second case presents some hydrodynamic results and water quality aspects of the Ria de Arosa (NW Spain), and also includes an assessment of the environmental impact of wastewater discharges from nine submarine outfalls considered in the sanitation plan of this bay. Results of faecal matter concentration distribution were used in the discussion on the outfall discharges’ impact on the natural water system for different hydrodynamic scenarios. In both cases, 3D numerical models were used

Modelação matemática da produção primária em zonas costeiras

O estudo da dinâmica de produção primária apresenta um interesse especial quando realizado em zonas costeiras utilizadas de forma intensiva para a aquicultura, como é o caso da Ria de Arosa. Nesta ria, a cadeia alimentar é dominada pelas elevadas taxas de produção primária sustentadas pelo afloramento de águas oceânicas ricas em nutrientes, resultando em elevadas quantidades de fitoplâncton que, por sua vez, servem de sustento às culturas de mexilhão em bateas. Neste artigo apresenta-se um modelo da cadeia alimentar proposto para a Ria de Arosa. Procede-se à apresentação das principais variáveis de estado seleccionadas e à caracterização das cinéticas que lhes estão associadas, evidenciando-se ainda as principais potencialidades de um modelo deste tipo na avaliação e previsão de cenários de funcionamento da cadeia alimentar

Oil spills in coastal zones : environmental impacts and practical mitigating solutions

A computational structure that has been developed to forecast the time-space evolution of oil spills in marine environments is presented. This structure was developed considering widely used mathematica formulations for oil spreading and weathering processes. A Eulerian transport model, that uses hydrodynamic results obtained with a two-dimensional and a quasi three-dimensional hydrodynamic model, was used to predict the oil slick transport and spread. General characteristics of the computational structure and the results of its application to a real case study - the “Cercal” accident in October 1994 - are presented. Georeferenced data are processed via a Geographical Information System tool. Data on the N/T “Prestige” oil spill processed by means of this information system and simulation results are also included.(undefined

Geometric approach to chaos in the classical dynamics of abelian lattice gauge theory

A Riemannian geometrization of dynamics is used to study chaoticity in the classical Hamiltonian dynamics of a U(1) lattice gauge theory. This approach allows one to obtain analytical estimates of the largest Lyapunov exponent in terms of time averages of geometric quantities. These estimates are compared with the results of numerical simulations, and turn out to be very close to the values extrapolated for very large lattice sizes even when the geometric quantities are computed using small lattices. The scaling of the Lyapunov exponent with the energy density is found to be well described by a quadratic power law.Comment: REVTeX, 9 pages, 4 PostScript figures include

Using low energy medical cyclotrons to produce 99mTc - Technetium

This article was retracted on 05 February 2014This paper refers to work in progress, addressing the global trouble in delivering 99mTc to Nuclear Medicine Departments, Aiming to develop an efficient, safe and economical way to directly produce Technetium 99metastable (99mTc) using lowenergy - so-called “medical” - cyclotrons. The present delivery strategy has intrinsic limitations because it is not only based on old nuclear reactors, but also limits the weekly agenda workflow. Our approach is distinct, and is based on the broad distribution network of the low energy cyclotrons and the accessibility of Molybdenum 100 (100Mo) as the target material, so the system here presented, is not based on the use of Nuclear Reactors and highly enriched (or even low enriched) Uranium 235 (235U), but entirely complying with the current international trends and directives, concerning the need to reduce the use of this potential highly critical target material. The direct production technique is based on the nuclear reaction 100Mo(p,2n)99mTc whose production yields have already been widely documented. The 99mTc is produced in a routine, reliable and efficient manner that, remaining always flexible, entirely blends with established protocols.info:eu-repo/semantics/publishedVersio