Size and shape of Mott regions for fermionic atoms in a two-dimensional optical lattice

We investigate the harmonic-trap control of size and shape of Mott regions in the Fermi Hubbard model on a square optical lattice. The use of Lanczos diagonalization on clusters with twisted boundary conditions, followed by an average over 50-80 samples, drastically reduce finite-size effects in some ground state properties; calculations in the grand canonical ensemble together with a local-density approximation (LDA) allow us to simulate the radial density distribution. We have found that as the trap closes, the atomic cloud goes from a metallic state, to a Mott core, and to a Mott ring; the coverage of Mott atoms reaches a maximum at the core-ring transition. A `phase diagram' in terms of an effective density and the on-site repulsion is proposed, as a guide to maximize the Mott coverage. We also predict that the usual experimentally accessible quantities, the global compressibility and the average double occupancy (rather, its density derivative) display detectable signatures of the core-ring transition. Some spin correlation functions are also calculated, and predict the existence N\'eel ordering within Mott cores and rings.Comment: 5 pages, 6 figure

Exploring Key-Value Stores in Multi-Writer Byzantine-Resilient Register Emulations

Resilient register emulation is a fundamental technique to implement dependable storage and distributed systems. In data-centric models, where servers are modeled as fail-prone base objects, classical solutions achieve resilience by using fault-tolerant quorums of read-write registers or read-modify-write objects. Recently, this model has attracted renewed interest due to the popularity of cloud storage providers (e.g., Amazon S3), that can be modeled as key-value stores (KVSs) and combined for providing secure and dependable multi-cloud storage services. In this paper we present three novel wait-free multi-writer multi-reader regular register emulations on top of Byzantine-prone KVSs. We implemented and evaluated these constructions using five existing cloud storage services and show that their performance matches or surpasses existing data-centric register emulations

A diferença de esperança de vida entre homens e mulheres: Portugal de 1940 a 2007

Neste artigo são analisadas as diferenças entre as esperanças de vida masculina e feminina, em Portugal de 1940 a 2007, com base na decomposição das contribuições de cada grupo etário e de cada causa de morte. Em termos cronológicos, esta investigação mostra a importância do declínio da mortalidade dos mais jovens na evolução na esperança de vida até aos anos 80 e o significado da descida da mortalidade dos adultos e, em especial, dos idosos na época actual. Relativamente à disparidade de esperança de vida entre os sexos, a desigualdade dependeu fundamentalmente da mortalidade diferencial dos adultos e dos idosos

ClimaWin : an intelligent window for optimal ventilation and minimum thermal loss

In this paper the ClimaWin concept is introduced. The ClimaWin project's main goals are to improve both indoor air quality and the energy efficiency of new and refurbished buildings, through the use of novel green smart windows. Generally, in order to improve windows' energy efficiency better insulation materials are used in windows frames and glasses. However, this approach leads to a severe deterioration of indoor air quality (IAQ) especially in buildings that are not equipped with heating, ventilation and air conditioning (HVAQ) systems. The Climawin windows do not require wires neither for power nor for communications. The window is powered through a battery (for blind operation) and a solar panel, which makes it an ideal solution for retrofitting. In order to achieve the energy efficiency requirements, the Climawin system hardware, the microcontroller software architecture and the radio communication strategy were designed for low power consumption. Furthermore, all the information about the system status can be monitored and actuated using intuitive graphical applications developed for PCs and Android OS smartphones. A remote database keeps all the relevant information about the system, making it easy to detect any anomaly or even to adjust the control algorithm parameters from a remote location. A full-set of web services are also provided in order to simplify the communication with home automation systems.Fundação para a Ciência e a Tecnologia (FCT

Diagnosing Potts criticality and two-stage melting in one-dimensional hard-boson models

We investigate a model of hard-core bosons with infinitely repulsive nearest- and next-nearest-neighbor interactions in one dimension, introduced by Fendley, Sengupta and Sachdev in Phys. Rev. B 69, 075106 (2004). Using a combination of exact diagonalization, tensor network, and quantum Monte Carlo simulations, we show how an intermediate incommensurate phase separates a crystalline and a disordered phase. We base our analysis on a variety of diagnostics, including entanglement measures, fidelity susceptibility, correlation functions, and spectral properties. According to theoretical expectations, the disordered-to-incommensurate-phase transition point is compatible with Berezinskii-Kosterlitz-Thouless universal behaviour. The second transition is instead non-relativistic, with dynamical critical exponent $z > 1$. For the sake of comparison, we illustrate how some of the techniques applied here work at the Potts critical point present in the phase diagram of the model for finite next-nearest-neighbor repulsion. This latter application also allows to quantitatively estimate which system sizes are needed to match the conformal field theory spectra with experiments performing level spectroscopy.Comment: 18 pages, 14 figure

Tipos habitacionais e estratégias de reabilitação do núcleo urbano antigo do Seixal

Os núcleos urbanos antigos são portadores de um património histórico e arquitectónico a proteger e a potenciar. Para tal, é necessário compreender a sua génese, tanto no plano do edifício como no plano do conjunto urbano. Deste modo, considera-se importante o estudo do edificado como apoio a intervenções de reabilitação qualificadas, conscientes e sustentáveis. Este artigo aborda o assunto dos núcleos urbanos antigos na perspectiva da análise e inventariação das características do edificado. O processo de tipificação apresenta-se como síntese das principais formas de construção presentes, baseado na inspecção (observação e levantamento) e registo, tomando como caso de estudo o Núcleo Urbano Antigo do Seixal

Exploiting Template Metaprogramming to customize an object-oriented operating system

Nowadays, the growing complexity of embedded systems demands for configurability, variability and reuse. Conditional compilation and object-orientation are two of the most applied approaches in the management of system variability. While the former increases the code management complexity, the latter leverages the needed modularity and adaptability to simplify the development of reusable and customizable software at the expense of performance and memory penalty. This paper shows how C++ TMP (Template Metaprogramming) can be applied to manage the variability of an object-oriented operating system and at the same time get ride out of the performance and memory footprint overhead. In doing so, it will be statically generated only the desired functionalities, thus ensuring that code is optimized and adjusted to application requirements and hardware resources.Fundação para a Ciência e a Tecnologia (FCT

Health and life expectancy differences: Portugal, Spain, Italy and France

In the 50’s the difference between the life expectancy in Portugal and the mean value in Europe was about 9 years; this discrepancy had gradually narrowed to 2 years in the mid 80’s. Since then, this difference had remained almost the same. We will focus our analysis in this period, after 1980, to get a closer look concerning the differences between Portugal and the other European countries as Spain, Italy and France. The observed differences in life expectancy will be decomposed: in the infant and child mortality, adult mortality and elderly mortality contributions. These specific contributions are associated both with the healthcare systems and also with the people attitudes and life styles. The Portuguese female life expectancy is the smaller one comparing to the other countries in study. In nowadays, the most important source of the differences in life expectancy is the elderly mortality. The mortality above 60 years old is the source of approximately 75% of the observed differences in life expectancy between Portugal and Italy and Spain and, 95% of the difference between Portugal and France. As for the male life expectancy, the Portuguese values are also the worse, but unlike for women, adult mortality is the major source of the observed discrepancies in the male case: almost 70% of the difference with Italy, almost 55% of the total difference with Spain and only 30% regarding France. We propose to discuss the adult and elderly contributions to the observed differences in life expectancies within the context of individual health related behaviours and national health systems

Architectonic and constructive characterisation of the old urban centre of Seixal, Portugal

This paper addresses the issue of the old urban centres from the perspective of the analysis and inventory of building features. The cataloguing process of the building typologies is presented herein as a synthesis of the main construction forms, with the old city centre of Seixal being used as a case study. Furthermore, and taking into account the relation between such two dimensions, a material and constructive characterisation of the buildings in the old urban centre of Seixal is presented. As marks of an historical and architectural heritage, old urban centres should be protected, safeguarded and potentiated. For such, it is fundamental to have a complete understanding of the genesis of both buildings and urban mesh. This fact is essential to the support of qualified, conscientious and sustainable rehabilitation interventions on the old building stock