Hamiltonian elliptic systems: a guide to variational frameworks

Consider a Hamiltonian system of type $$-\Delta u=H_{v}(u,v),\ -\Delta v=H_{u}(u,v) \ \ \text{ in } \Omega, \qquad u,v=0 \text{ on } \partial \Omega$$ where $H$ is a power-type nonlinearity, for instance $H(u,v)= |u|^p/p+|v|^q/q$, having subcritical growth, and $\Omega$ is a bounded domain of $\mathbb{R}^N$, $N\geq 1$. The aim of this paper is to give an overview of the several variational frameworks that can be used to treat such a system. Within each approach, we address existence of solutions, and in particular of ground state solutions. Some of the available frameworks are more adequate to derive certain qualitative properties; we illustrate this in the second half of this survey, where we also review some of the most recent literature dealing mainly with symmetry, concentration, and multiplicity results. This paper contains some original results as well as new proofs and approaches to known facts.Comment: 78 pages, 7 figures. This corresponds to the second version of this paper. With respect to the original version, this one contains additional references, and some misprints were correcte

Cultural accessible pedestrian ways. The case of Faro historic centre

In a historic city the existence of accessible pedestrian routes constitutes an essential feature to a true access to culture heritage, contributing for processes of social inclusion. It is necessary to create accessible pedestrian infrastructures network to hold a set of attributes that guarantee usability for all citizens. The creation and design of an accessible physical environment should be considered as a criterion of urban quality, which will make walking more pleasant not only for the elderly and people with disabilities but, also, for the entire resident population and tourists. In this case study it is ascertainable whether the physical characteristics of pedestrian infrastructures of cultural interest, located in the Historical Centre of Faro (Portugal), comply with the requirements of the National Law of Accessibility. There has, therefore, been created a methodology for evaluating the accessibility of pedestrian infrastructure through the construction of performance indicators. The analysis is achieved through a model of evaluation of the degree of conformity of the spaces, and presented, spatially, with appeal to a Geographical Information System, which is a tool to support the decision taking in the processes of urban rehabilitation, thus contributing to the choice of priority areas of intervention in the field of accessibility. The diagnosis confirms the existence of inaccessible pedestrian infrastructure and concludes the need to trigger processes of urban renovation.info:eu-repo/semantics/publishedVersio

Gas and solid behaviours during defluidisation of Geldart-A particles

Bed collapsing experiments were carried out in a cold-air transparent column 192 mm in diameter and 2 m high. Typical Fluid Catalytic Cracking (FCC) catalyst with a mean particle size of 76 μm and a density of 1400 kg/m3 was used. Both single and double-drainage protocols were tested. The local pressure drop and bed surface collapse height were acquired throughout the bed settling.Typical results were found regarding dense phase voidage of a fluidised bed and the bed surface collapse velocity. In addition, bubble fraction was calculated based on the collapse curve.Experimental results showed that windbox effect is significantly reduced compared to previous works since the volume of air within the windbox was reduced. The comparison of single/double-drainage protocols revealed a new period in the defluidisation of Geldart-A particles concerning gas compressibility. Through the temporal analysis of local pressure drop, the progress of the solid sedimentation front from bottom to top was determined, analysed and modelled

Sobreviventes

Marcado por estigma e tabus, o suicídio é frequentemente percecionado como uma morte confusa, com causas complexas, multideterminadas e mal compreendidas. Para quem o comete pode ser visto como libertador e finalizador de uma dor psicológica insuportável, mas para os entes próximos e significativos, o suicídio representa habitualmente o início de um percurso de sofrimento intenso, que os enclausura numa herança aterradora e desconcertante, quase sempre cristalizada num pacto de silêncio impenetrável, agoniante e transformador de vida. [...

Diffusion-limited deposition with dipolar interactions: fractal dimension and multifractal structure

Computer simulations are used to generate two-dimensional diffusion-limited deposits of dipoles. The structure of these deposits is analyzed by measuring some global quantities: the density of the deposit and the lateral correlation function at a given height, the mean height of the upper surface for a given number of deposited particles and the interfacial width at a given height. Evidences are given that the fractal dimension of the deposits remains constant as the deposition proceeds, independently of the dipolar strength. These same deposits are used to obtain the growth probability measure through Monte Carlo techniques. It is found that the distribution of growth probabilities obeys multifractal scaling, i.e. it can be analyzed in terms of its $f(\alpha)$ multifractal spectrum. For low dipolar strengths, the $f(\alpha)$ spectrum is similar to that of diffusion-limited aggregation. Our results suggest that for increasing dipolar strength both the minimal local growth exponent $\alpha_{min}$ and the information dimension $D_1$ decrease, while the fractal dimension remains the same.Comment: 10 pages, 7 figure

Comparative Analysis of the Importance of Determining Factors in the Choice and Sale of Apartments

The motivation to compare the importance that buyers and sellers give to the diverse characteristics of apartments is its pertinency to grasping the housing market. The objective of this article is to compare the determining factors in the choice and sale of apartments among the potential buyers and sellers. During a sale, the realtors exhibit the dwellings’ positive characteristics, the so-called amenities. The homebuyers must analyse the deal in a rational and well-weighed way, striving to know its characteristics to reduce the information asymmetry. The study focuses on two distinct samples, with the common goal of transacting housing. One of the samples is composed of individuals who are looking for apartments, and the other one of individuals who are selling apartments, both being collected in mainland Portugal. It was verified that there are statistically significant differences between buyers and sellers. Buyers give more importance to certain rooms and the inexistence of negative externalities near their future residence. Sellers emphasise positive externalities and parking spots. This study is expected to contribute to the increase in scientific knowledge on the housing market and to the decrease of the information asymmetry between sellers and buyers. Knowing the importance that buyers and sellers give to the main different factors in the Portuguese real estate market constitutes an advancement of knowledge in this area.info:eu-repo/semantics/publishedVersio

The Perception and Knowledge of Financial Risk of the Portuguese

This study will help academics, researchers, and professionals to better understand how the Portuguese population perceives financial risk. Thus, the main objective of this study is to analyse and compare the perception and knowledge of financial risk by the Portuguese. The methodology used is quantitative, and the measurement instrument consists of three parts: financial risk perception, financial risk knowledge and sociodemographic characterization of the participants. The sample is composed of 830 Portuguese individuals, over 18 years old. The results demonstrate that financial risk perception is a one-dimensional measurement and that there are low levels of both perception and knowledge of financial risk. It can also be concluded that the Portuguese individuals have a higher level of financial risk perception, when compared to financial risk knowledge, and it is men who have higher levels of perception and knowledge of financial risk. Thus, this study contributes to the literature on financial risk by presenting empirical evidence and relevant conclusions, and it is therefore expected that it will help to improve the perception and knowledge of the financial risk of the Portuguese and, consequently, their financial decisions and financial well-being. Therefore, the study fills a gap, since there are no studies in Portugal that assess the perception and knowledge of financial risk of the Portuguese.info:eu-repo/semantics/publishedVersio

Validation of an Information Asymmetry Scale in the Portuguese Real Estate Market

Purpose – The motivation to study the information asymmetry in the real estate market comes from the fact that this market is far from being efficient and perfect, and buying a house is, for most families, the biggest deal of their lives. This paper aims to validate a scale that evaluates the information asymmetry in the Portuguese real estate market. Theoretical framework – During the sales negotiation process, estate agents exhibit the positive aspects of the house, as well as its amenities and qualities, and camouflage the least positive aspects of the deal. Finding both the positive and the negative aspects is crucial. Design/methodology/approach – To collect the sample, an instrument based on a questionnaire survey was used, which analyses the information asymmetry in the real estate market and the sociodemographic profile of estate agents in Portugal. The sample is composed of 350 commercial delegates from the three biggest real estate mediation companies in the Portuguese market. Findings – The results show that the scale for the information asymmetry in the Portuguese real estate market is composed of six factors, which present adequate levels of validity and reliability: negative externalities, possibilities of making a deal, housing quality, service areas, proximity to businesses, and positive externalities. Practical & social implications of research – This study is expected to contribute to improving the scientific knowledge on the real estate market, and to enhancing the information transmitted by estate agents to their future clients. Originality/value – In Portugal, there is no study with such depth about this topic of research. The validation of the information asymmetry scale in the Portuguese real estate market represents a breakthrough in the knowledge in this area.info:eu-repo/semantics/publishedVersio