Finite volume corrections to pi-pi scattering

Lattice QCD studies of hadron-hadron interactions are performed by computing the energy levels of the system in a finite box. The shifts in energy levels proportional to inverse powers of the volume are related to scattering parameters in a model independent way. In addition, there are non-universal exponentially suppressed corrections that distort this relation. These terms are proportional to exp(-m_pi L) and become relevant as the chiral limit is approached. In this paper we report on a one-loop chiral perturbation theory calculation of the leading exponential corrections in the case of I=2 pi-pi scattering near threshold.Comment: 17 pages, 2 figures, 1 table. Version published in PR

Automatic allocation of safety requirements to components of a software product line

Safety critical systems developed as part of a product line must still comply with safety standards. Standards use the concept of Safety Integrity Levels (SILs) to drive the assignment of system safety requirements to components of a system under design. However, for a Software Product Line (SPL), the safety requirements that need to be allocated to a component may vary in different products. Variation in design can indeed change the possible hazards incurred in each product, their causes, and can alter the safety requirements placed on individual components in different SPL products. Establishing common SILs for components of a large scale SPL by considering all possible usage scenarios, is desirable for economies of scale, but it also poses challenges to the safety engineering process. In this paper, we propose a method for automatic allocation of SILs to components of a product line. The approach is applied to a Hybrid Braking System SPL design

Generalised quantum tree search

This extended abstract reports on on-going research on quantum algorithmic approaches to the problem of generalised tree search that may exhibit effective quantum speedup, even in the presence of non-constant branching factors. Two strategies are briefly summarised and current work outlined.This research is financed by the ERDF through the Opera tional Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT, within project POCI-01- 0145-FEDER-03094

Enhancement of optical absorption by modulation of the oxygen flow of TiO2 films deposited by reactive sputtering

Oxygen-deficient TiO2 films with enhanced visible and near-infrared optical absorption have been deposited by reactive sputtering using a planar diode radio frequency magnetron configuration. It is observed that the increase in the absorption coefficient is more effective when the O2 gas supply is periodically interrupted rather than by a decrease of the partial O2 gas pressure in the deposition plasma. The optical absorption coefficient at 1.5 eV increases from about 1 102 cm 1 to more than 4 103 cm 1 as a result of the gas flow discontinuity. A red-shift of 0.24 eV in the optical absorption edge is also observed. High resolution transmission electron microscopy with composition analysis shows that the films present a dense columnar morphology, with estimated mean column width of 40 nm. Moreover, the interruptions of the O2 gas flow do not produce detectable variations in the film composition along its growing direction. X-ray diffraction and micro-Raman experiments indicate the presence of the TiO2 anatase, rutile, and brookite phases. The anatase phase is dominant, with a slight increment of the rutile and brookite phases in films deposited under discontinued O2 gas flow. The increase of optical absorption in the visible and near-infrared regions has been attributed to a high density of defects in the TiO2 films, which is consistent with density functional theory calculations that place oxygen-related vacancy states in the upper third of the optical bandgap. The electronic structure calculation results, along with the adopted deposition method and experimental data, have been used to propose a mechanism to explain the formation of the observed oxygen-related defects in TiO2 thin films. The observed increase in sub-bandgap absorption and the modeling of the corresponding changes in the electronic structure are potentially useful concerning the optimization of efficiency of the photocatalytic activity and the magnetic doping of TiO2 films

Microstructure identification via detrended fluctuation analysis of ultrasound signals

We describe an algorithm for simulating ultrasound propagation in random one-dimensional media, mimicking different microstructures by choosing physical properties such as domain sizes and mass densities from probability distributions. By combining a detrended fluctuation analysis (DFA) of the simulated ultrasound signals with tools from the pattern-recognition literature, we build a Gaussian classifier which is able to associate each ultrasound signal with its corresponding microstructure with a very high success rate. Furthermore, we also show that DFA data can be used to train a multilayer perceptron which estimates numerical values of physical properties associated with distinct microstructures.Comment: Submitted to Phys. Rev.

The use of vasopressors during anaesthesia for caesarean section: a retrospective observational study

info:eu-repo/semantics/publishedVersio

Epidural top-up for caesarean section: a retrospective observational study

info:eu-repo/semantics/publishedVersio

Sistema de alvenaria com incorporação de resíduos: blocos de terra compactada com ligante geopolimérico

A produção de resíduos é um problema comum a todas as sociedades, que importa gerir de forma adequada para proteger o meio ambiente do impacto que atividade do Homem lhe provoca. O setor da construção civil é responsável por uma percentagem muito importante dos resíduos produzidos anualmente a nível Mundial. Como tal, exige-se que os agentes ligados a este setor desenvolvam soluções construtivas que promovam a valorização dos resíduos, com base na sua reciclagem em novos materiais de construção. Estes materiais, ao entrarem no mercado e ao serem integrados nas construções, permitiram substituir parte dos materiais correntes por materiais reciclados. Da execução de uma construção resultam resíduos compostos por diversas fileiras de materiais, de onde se destacam os solos resultantes de trabalhos de escavação, que podem ser reutilizados em trabalhos de aterro/enchimento necessários em obra, mas os solos excedentes constituem um problema a gerir. Estes solos podem ser reutilizados em outras obras ou transportados para uma bolsa de solos, onde aguardam reutilização. Contudo, os solos excedentes podem constitur um recurso que pode ser valorizado através da promoção de um uso alternativo em obra. No presente artigo pretende-se caracterizar o desempenho mecânico de um sistema de alvenaria à base de blocos de terra compactada (BTC). Estes BTC foram desenvolvidos com base na incorporação de solo residual granítico (SRG), típico do Norte de Portugal, estabilizado com um ligante geopolimérico. Este ligante é obtido por ativação alcalina de um outro resíduo, proveniente da indústria energética, nomeadamente as cinzas volantes. O desempenho do sistema de alvenaria de BTC foi avaliado através de um programa experimental, constatando-se um bom desempenho mecânico da solução.Este trabalho foi financiado por fundos do FEDER através do Programa Operacional Fatores de Competitividade – COMPETE e por fundos nacionais, através da Fundação para Ciência e a Tecnologia - FCT no âmbito do projeto POCI-01-0145-FEDER-007633 e da bolsa de pósdoutoramento FRH/BPD/97082/2013. Os autores agradecem ao Pedro Esteves o seu contributo na execução do programa experimental e ao Eng.º Jorge Henriques, em representação da PEGOP – Energia Elétrica SA, pela disponibilização da cinza volante