Differential phase extraction in an atom gradiometer

We present here a method for the extraction of the differential phase of an atom gradiometer that exploits the correlation of the vibration signal measured by an auxiliary classical sensor, such as a seismometer or an accelerometer. We show that sensitivities close to the quantum projection noise limit can be reached, even when the vibration noise induces phase fluctuations larger than 2$\pi$. This method doesn't require the correlation between the atomic and classical signals to be perfect and allows for an exact determination of the differential phase, with no bias. It can also be applied to other configurations of differential interferometers, such as for instance gyrometers, conjugate interferometers for the measurement of the fine structure constant, or differential accelerometers for tests of the equivalence principle or detection of gravitational waves

From an agrarian society to a knowledge economy: Portugal, 1950-2010

This paper surveys the main features of Portuguese economic growth in the last half century, with a particular emphasis on the period after the return to democracy in 1974. It shows that significant structural change and capital deepening were the chief sources of growth in the Portuguese economy until the mid 1970s. From then onwards, human capital accumulation and productivity growth were the main reasons behind Portugal’s economic fortunes. Growth declined between these two phases, as in the rest of Europe. In Portugal, it slowed further after 1990. After surveying the main causes of the slowdown of the Portuguese economy in the last decade, Portugal’s main human capital indicators are compared to other European and OECD economies. While Portugal has made a remarkable transition from an agrarian society to an industry- and service-based economy, the country still has not been able to successfully move on to a knowledge-based economy. Such a transition, however, is instrumental to spur economic growth on and to improve productivity.Economic policies, Economic growth, Human Capital, Portugal

Drinking patterns among Portuguese university students: gender differences and association with self-perception of mental health

Alcohol abuse is one of the most concerning risk behaviours in higher education. Therefore, this study aims to: characterize alcohol consumption among Portuguese university students; investigate gender differences; analyse the association between alcohol use and the perception of mental health. 174 Portuguese students completed a questionnaire about risk behaviours and rated their self-perceptions of mental health. Results show that 17.3% of the students haven’t consumed any alcohol during the last month, while, on the opposite side, 11% of those who drank, reported having binge episodes at least twice a week. Men drank significantly more often; more drinks at a time and had more risk behaviours associated with alcohol, than women. A significant, yet very weak, positive correlation was found between the amount of alcohol consumed and the self-perception of mental health. Results are debated in light of relevant literature and suggestions for prevention are discussed.This investigation was supported by a FCT scholarship (SFRH/BD30085/2006

An LP-Based Approach for Goal Recognition as Planning

Goal recognition aims to recognize the set of candidate goals that are compatible with the observed behavior of an agent. In this paper, we develop a method based on the operator-counting framework that efficiently computes solutions that satisfy the observations and uses the information generated to solve goal recognition tasks. Our method reasons explicitly about both partial and noisy observations: estimating uncertainty for the former, and satisfying observations given the unreliability of the sensor for the latter. We evaluate our approach empirically over a large data set, analyzing its components on how each can impact the quality of the solutions. In general, our approach is superior to previous methods in terms of agreement ratio, accuracy, and spread. Finally, our approach paves the way for new research on combinatorial optimization to solve goal recognition tasks.Comment: 8 pages, 4 tables, 3 figures. Published in AAAI 2021. Updated final authorship and tex

Vortex distribution in a confining potential

We study a model of interacting vortices in a type II superconductor. In the weak coupling limit, we constructed a mean-field theory which allows us to accurately calculate the vortex density distribution inside a confining potential. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. Contrary to recent suggestions, this does not imply failure of the Boltzmann-Gibbs statistical mechanics, as we clearly demonstrate by comparing the results of Molecular Dynamics and Monte Carlo simulations