Oscillatons revisited

In this paper, we study some interesting properties of a spherically symmetric oscillating soliton star made of a real time-dependent scalar field which is called an oscillaton. The known final configuration of an oscillaton consists of a stationary stage in which the scalar field and the metric coefficients oscillate in time if the scalar potential is quadratic. The differential equations that arise in the simplest approximation, that of coherent scalar oscillations, are presented for a quadratic scalar potential. This allows us to take a closer look at the interesting properties of these oscillating objects. The leading terms of the solutions considering a quartic and a cosh scalar potentials are worked in the so called stationary limit procedure. This procedure reveals the form in which oscillatons and boson stars may be related and useful information about oscillatons is obtained from the known results of boson stars. Oscillatons could compete with boson stars as interesting astrophysical objects, since they would be predicted by scalar field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version published in Classical and Quantum Gravit

Analysis of process variables via CFD to evaluate the performance of a FCC riser

Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process

The impact of the Covid-19 pandemic on the execution of educational measures in the community

This study is part of the JUST COVID 19 project (Universidade Católica Portuguesa), in partnership with the YO&JUST project (Universidade NOVA de Lisboa) and its overall objective is to understand the impact of the COVID 19 pandemic on the execution of educational measures in the community. Although this phenomenon is recent, international studies have already highlighted its impact on justice systems and juvenile delinquency (Gordon, Klose, & Lyttle Storrod, 2020; Buchanan, Castro, Kushner, & Krohn, 2020; McCarthy, Homel, Ogilvie & Allard, 2021). However, at national level, there is a lack of research on this topic, thus making this study an added value to understand this reality and subsequently bring contributions that safeguard the interests of children and young people. In order to achieve the defined objectives, interviews were carried out with seven professionals working in the Portuguese juvenile justice system, particularly in the metropolitan areas of Porto and Lisbon and in Alto Alentejo. The Annual Statistical Reports of the Direção Geral de Reinserção e Serviços Prisionais from 2015 to 2020 and the Reports from February, May and December 2021 of the same entity were also used. The analysis of the data allowed evidencing several impacts arising from the pandemic in the execution of tutelary educational measures in the community.info:eu-repo/semantics/publishedVersio

COVID-19 pandemic and the use of illicit substances in young people with delinquent behaviors

This study is part of the JUST COVID-19 (UCP) and YO&JUST (CICS-NOVA) projects, aiming to understand the impact of the covid-19 pandemic on the use of illicit substances by young people with delinquent behaviours. Early onset of substance use in adolescence has been associated with increased delinquency and subsequent criminality, specifically including violent crime, and being at particularly high risk of serious problems later in life (Gordon et al., 2004). As the pandemic progressed, containment measures were implemented. Social distancing to decrease interaction between individuals (Duarte, 2020), the closure of schools and other places that provided crowding of the population (Schmidt, 2020), as well as the general isolation caused in young people various stressors such as fear of being infected, distress, loneliness, anxiety and depression (Scalia et al., 2020). These variables may have caused changes in the contexts and patterns of illicit substance use. To understand such changes several professionals who work with young people with deviant behaviours were interviewed. In this poster, we present the study and its main results.info:eu-repo/semantics/publishedVersio

Mixed-source multi-document speech-to-text summarization

Speech-to-text summarization systems usually take as input the output of an automatic speech recognition (ASR) system that is affected by issues like speech recognition errors, disfluencies, or difficulties in the accurate identification of sentence boundaries. We propose the inclusion of related, solid background information to cope with the difficulties of summarizing spoken language and the use of multi-document summarization techniques in single document speech- to-text summarization. In this work, we explore the possibilities offered by pho- netic information to select the background information and conduct a perceptual evaluation to better assess the relevance of the inclusion of that information. Results show that summaries generated using this approach are considerably better than those produced by an up-to-date latent semantic analysis (LSA) summarization method and suggest that humans prefer summaries restricted to the information conveyed in the input source.info:eu-repo/semantics/publishedVersio