Spectroscopic binaries in the Solar Twin Planet Search program: from substellar-mass to M dwarf companions

Previous studies on the rotation of Sun-like stars revealed that the rotational rates of young stars converge towards a well-defined evolution that follows a power-law decay. It seems, however, that some binary stars do not obey this relation, often by displaying enhanced rotational rates and activity. In the Solar Twin Planet Search program we observed several solar twin binaries, and found a multiplicity fraction of $42\% \pm 6\%$ in the whole sample; moreover, at least three of these binaries (HIP 19911, HIP 67620 and HIP 103983) clearly exhibit the aforementioned anomalies. We investigated the configuration of the binaries in the program, and discovered new companions for HIP 6407, HIP 54582, HIP 62039 and HIP 30037, of which the latter is orbited by a $0.06$ M$_\odot$ brown dwarf in a 1-month long orbit. We report the orbital parameters of the systems with well-sampled orbits and, in addition, the lower limits of parameters for the companions that only display a curvature in their radial velocities. For the linear trend binaries, we report an estimate of the masses of their companions when their observed separation is available, and a minimum mass otherwise. We conclude that solar twin binaries with low-mass stellar companions at moderate orbital periods do not display signs of a distinct rotational evolution when compared to single stars. We confirm that the three peculiar stars are double-lined binaries, and that their companions are polluting their spectra, which explains the observed anomalies.Comment: 13 pages, 7 figures, accepted for publication in MNRA

A diversificação das receitas bancárias: seu impacto sobre o risco e o retorno dos bancos brasileiros

O objetivo deste estudo é determinar o impacto da diversificação das receitas bancárias sobre o risco e o retorno dos bancos brasileiros. Essa estratégia foi adotada por bancos em diversos países, inclusive no Brasil. Em 2003, as receitas noninterest (não decorrentes de juros) representavam 17,80% da receita operacional dos bancos analisados e, em 2014, essa participação havia aumentado para 27,40%. Embora muitos estudos tenham abordado a questão para bancos americanos, europeus e asiáticos, este tema ainda não foi abordado para uma amostra de bancos brasileiros. Como o setor bancário é uma variável crucial à estabilidade do sistema financeiro, é importante estudar os fatores que afetam o risco e o retorno dos bancos. Analisamos a amostra para o período entre 2003 e 2014, utilizando dados em painel dinâmico através do Método Generalizado dos Momentos para abordar questões de endogeneidade, heterocedasticidade e autocorrelação. Nossos principais resultados mostram que as receitas noninterest possuem um papel importante no desempenho dos bancos estudados; nossa análise das atividades de intermediação financeira mostrou que as operações de crédito produziram melhores resultados do que as atividades de negociação de títulos. Além disso, confirmando as hipóteses propostas, as receitas noninterest apresentaram, de maneira geral, um impacto positivo sobre o retorno e o retorno ajustado ao risco nos bancos estudados. Entretanto, ao contrário do que esperávamos, as receitas noninterest mostraram uma relação positiva com o risco desses bancos (embora estatisticamente não significativa). É importante destacar as variáveis de controle, ou seja, a taxa de juros real, o PIB e o crescimento bancário, as quais foram relevantes para a determinação do desempenho dos bancos.The present study aims to determine the impact of bank revenue diversification on Brazilian banks’ risk and return. This strategy has been adopted by banks in several countries, including Brazil. In 2003, noninterest income accounted for 17.80% of the operating revenue of the banks analyzed, and in 2014, this share increased to 27.40%. While many studies have addressed the subject in American, European and Asian banks, it still has not been approached in a sample of Brazilian banks. Since the banking industry is a key variable for the financial system’s stability, it is important to study the factors that affect banks’ risk and return. We analyzed the sample for the period from 2003 to 2014, using dynamic panel data GMM (Generalized Method of Moments) to address endogeneity, heteroscedasticity and autocorrelation problems. Our main results show that noninterest income has a major role in the performance of the banks studied; our analysis of financial intermediation activities showed that loan operations produced better results than trading. Moreover, confirming the hypotheses proposed, noninterest income showed a generally positive impact on return and risk adjusted return for the banks studied. However, against our expectation, noninterest income showed a positive relationship with the risk of these banks (although not statistically significant). It is worth highlighting the control variables, i.e., real interest rate, GDP and bank growth, which were relevant in determining bank performance

A Cross-Functional Approach for the Fuzzy Front End: Highlights from a Conceptual Project

Ideation is regarded as a critical element in the innovation process; besides, it is transversal to the different design models. Notwithstanding its fundamental characteristics for the innovation process, ideation is the least-studied phase and an ambiguous nature is sometimes assigned to it. Consequently, the Fuzzy Front End (FFE) designation was born to describe this early phase and the interest over its study has recently increased. By means of an extensive literature review, ideation is highlighted from the design process and diverging models for the FFE are comparatively analyzed. The importance of a cross-functional approach for the FFE is underpinned with an analysis of a multidisciplinary and mainly conceptual project over the transportation sector. The innovative character and the perceived value of this project is precisely grounded in its integrated and cross-functional approach, which combines the technological possibilities with the passenger focus

The temporal evolution of neutron-capture elements in the Galactic discs

Important insights into the formation and evolution of the Galactic disc(s) are contained in the chemical compositions of stars. We analysed high-resolution and high signal to noise HARPS spectra of 79 solar twin stars in order to obtain precise determinations of their atmospheric parameters, ages ($\sigma$$\sim$0.4 Gyr) and chemical abundances ($\sigma$$<$0.01~dex) of 12 neutron-capture elements (Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, and Dy). This valuable dataset allows us to study the [X/Fe]-age relations over a time interval of $\sim$10 Gyr and among stars belonging to the thin and thick discs. These relations show that i) the $s$-process has been the main channel of nucleosynthesis of $n$-capture elements during the evolution of the thin disc; ii) the thick disc is rich in $r$-process elements which suggests that its formation has been rapid and intensive. %; iii) a chemical continuity between the thin and thick discs is evident in the abundances of Ba. In addition, the heavy (Ba, La, Ce) and light (Sr, Y, Zr) $s$-process elements revealed details on the dependence between the yields of AGB stars and the stellar mass or metallicity. Finally, we confirmed that both [Y/Mg] and [Y/Al] ratios can be employed as stellar clocks, allowing ages of solar twin stars to be estimated with an average precision of $\sim$0.5~Gyr

Validity of the two-minute step test for healthy older adults.

pre-print828 K

A fast and precise tool for multi-layer planar coil self-inductance calculation

An open-source tool that allows for a fast and precise analytical calculation of multi-layer planar coils self-inductance, without any geometry limitation is proposed here. The process of designing and simulating planar coils to achieve reliable results is commonly limited on accuracy and or geometry, or are too time-consuming and expensive, thus a tool to speed up this design process is desired. The model is based on Grover equations, valid for any geometry. The validation of the tool was performed through the comparison with experimental measurements, Finite Element Model (FEM) simulations, and the main analytical methods usually used in literature, with errors registered to be below 2.5%, when compared to standard FEM simulations, and when compared to experimental measurements they are below 10% in the case of the 1-layer coils, and below 5% in the 2-layer coils (without taking into consideration the coil connectors). The proposed model offers a new approach to the calculation of the self-inductance of planar coils of several layers that combines precision, speed, independence of geometry, easy interaction, and no need for extra resources.This work is supported by: European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 037902; Funding Reference: POCI-01-0247-FEDER-037902]. The work of Andreia Faria was funded by FCT—Fundação para a Ciência e Tecnologia under Grant PD/BD/128142/2016. The work of Carlos Ferreira was supported by the Fundação para a Ciência e Tecnologia (FCT) under Grant PD/BDE/135102/2017

Análise da estabilidade de pilares de zircónia 3Y-TZP após carga cíclica e termociclagem

Objectives: Although implant abutments made of yttria-stabilized tetragonal zirconia poly crystal (3Y-TZP) show great predictability, some issues related to its aging require further study. The objective of this in vitro study is to assess the stability of 3Y-TZP zirconia implant abutments with two different implant connections when subjected to aging simulation through thermocycling and mechanical loading (TCML).Methods: Ten 3Y-TZP zirconia abutments were selected and equally divided into two groups (n = 5): CEZr, abutments for externally hexed implants; and CIZr, abutments for implants with an internal conical connection. The samples were subjected to thermocycling (5000 cycles; 5-55 C) and mechanical loading (1.2 x 106 cycles; 88.8 N; 4 Hz). Before and after the aging procedures, X-ray diffraction (XRD) analysis was conducted to observe tetragonal monoclinic (t-m) phase transformation, and topographic surface analysis was performed by 3D profilometry, and data were analyzed using Mann-Witney test (p 0.05), before and after TCML, and between implants connections (test U= 57.0, p = 0.053 > 0.05) were not detected.Conclusions: After a 5-year simulation of its clinical use, the analyzed 3Y-TZP zirconia abutments did not show signs of aging. The connection's geometry does not interfere in aging.Objetivos Os pilares de zircónia tetragonal policristalina (Y-TZP) apresentam grande previsibilidade na sua utilização clínica. No entanto, existem ainda alguns aspetos relacionados com o envelhecimento que necessitam de ser estudados. O presente trabalho pretendeu avaliar a estabilidade de pilares de zircónia 3Y-TZP de 2 conexões implantares diferentes, quando submetidos a simulação de envelhecimento (TCML). Métodos Foram selecionados 10 pilares em zircónia 3Y-TZP, que foram divididos em 2 grupos (n = 5): CEZr, pilares para implantes de conexão de hexágono externo; e CIZr, pilares para implantes de conexão interna cónica-lobular. As amostras foram submetidas a termociclagem (5000 ciclos; 5-55 °C) e carga cíclica (1,2 × 106 ciclos; 88,8 N; 4 Hz). Antes e após TCML, os pilares foram sujeitos a análise por difração de raios X para determinação de alteração de fase cristalográfica de tetragonal para monoclínica (t-m) e a interferometria ótica sobre a superfície de assentamento das 2 conexões para a medição da sua topografia por perfilometria 3D. Análise estatística: Mann-Whitney test (p < 0,05). Resultados Após TCML não foi detetada fase monoclínica em nenhum dos pilares. A análise comparativa da rugosidade (com utilização do parâmetro Sa) sobre as plataformas protéticas dos pilares revelou ligeiro aumento da Sa em ambas as conexões após TCML. Não foram observadas diferenças estatisticamente significativas nos valores de Sa (test U = 57,0, p = 0,161 > 0,05), antes e após TCML, e entre conexões dos implantes (test U = 57,0, p = 0,053 > 0,05). Conclusões Após uma simulação de 5 anos de utilização clínica, os pilares de zircónia 3Y-TZP analisados não apresentaram sinais de envelhecimento. A geometria das conexões não interferiu no envelhecimento.Authors gratefully acknowledge the funding of Project NORTE-01-0145-FEDER-000022 - SciTech - Science and Technology for Competitive and Sustainable Industries, cofinanced by Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER)

“Surfing in the cell” - an investigative game for teaching cytoskeleton concepts for undergraduate students

The educational role of games becomes evident as students are more active, able to take decisions, solve problems and react to the results of their own decisions. The educative board game Discovering the Cell is based on problem-solving learning. This game challenges students to collect, discuss and interpret clues in order to decipher a question. In this work we evaluated the game as a tool for teaching health sciences undergraduate students from Rio de Janeiro. In a questionnaire-based analysis, students demonstrated great acceptance for this strategy and the majority of them were able to solve the Case tested, as well as applying the learned content to answer a related question. Taken together, our results indicate the acceptance and suitability of the game as an alternative strategy to help teaching cell and molecular biology to undergraduate students

A novel modular voltage balancing topology for active battery management system

This paper proposes a novel modular voltage balancing topology for an active battery management system (BMS). The proposed topology consists of two power stages. The first stage is composed by a switch network, which is responsible for selecting the battery that will provide energy and the battery that will receive energy. In the switch network, for each battery, are used two cells, which allow the operation with bidirectional current flow and bipolar voltage. The second stage is composed by a capacitor used as energy storage element, which consists in the component used to link both batteries. The switch network control and its interaction with the energy storage element is performed by a digital controller. The paper presents the main computer simulations, as well as the main experimental results obtained to validate the proposed voltage balancing topology for an active BMS.This work has been supported by FCT - Fundação para a Ciência e Tecnologia in the scope of the project: PEst-UID/CEC/00319/2013. Mr. Vítor Monteiro was supported by the doctoral scholarship SFRH/BD/80155/2011 granted by the FCT agency