Aims. We have analyzed high-resolution and high signal-to-noise-ratio optical spectra of nearby FGK stars with and without detected giant planets in order to homogeneously measure their photospheric parameters, mass, age, and the abundances of volatile (C, N, and O) and refractory (Na, Mg, Si, Ca, Ti, V, Mn, Fe, Ni, Cu, and Ba) elements. Our sample contains 309 stars from the solar neighborhood (up to the distance of 100 pc), out of which 140 are dwarfs, 29 are subgiants, and 140 are giants. [Na/Fe] in comparison with dwarfs, a result that is normally attributed to evolution-induced mixing processes in the envelope of evolved stars; ii) for solar analogs alone, the abundance trends with the condensation temperature of the elements are correlated with age and anticorrelated with the surface gravity, which agrees with recent studies; iii) as in the case of [Fe/H], dwarf stars with giant planets are systematically enriched in [X/H] for all the analyzed elements, except for O and Ba (the former due to limitations of statistics), confirming previous findings in the literature that it is not only iron that has an important relation with the planetary formation; and iv) giant planet hosts are also significantly overabundant for the same metallicity when the elements from Mg to Cu are combined.

No abstract

We present accurate and deep multiband (g, r, i) photometry of the Local Group dwarf irregular galaxy NGC 6822. The images were collected with wide-field cameras at 2 m/4 m (INT, CTIO, CFHT) and 8 m class telescopes (Subaru) covering a 2 deg2 field of view across the center of the galaxy. We performed point-spread function photometry of ≈7000 CCD images, and the final catalog includes more than 1 million objects. We developed a new approach to identify candidate field and galaxy stars and performed a new estimate of the galaxy center by using old stellar tracers, finding that it differs by 1.′15 (R.A.) and 1.′53 (decl.) from previous estimates. We also found that young (main sequence, red supergiants), intermediate (red clump, asymptotic giant branch (AGB)), and old (red giant branch) stars display different radial distributions. The old stellar population is spherically distributed and extends to radial distances larger than previously estimated (∼1°). The young population shows a well-defined bar and a disk-like distribution, as suggested by radio measurements, that is off-center compared with the old population. We discuss pros and cons of the different diagnostics adopted to identify AGB stars and develop new ones based on optical–near-IR–mid-IR color–color diagrams to characterize oxygen- and carbon-rich stars. We found a mean population ratio between carbon and M-type (C/M) stars of 0.67 ± 0.08 (optical/near-IR/mid-IR), and we used the observed C/M ratio with empirical C/M–metallicity relations to estimate a mean iron abundance of [Fe/H] ∼ −1.25 (σ = 0.04 dex), which agrees quite well with literature estimates.

To sing while taking melodic dictation is a strategy employed by some Ear Training students as an aid, but there is a disagreement among the literature about its efficiency. Thus, it is important to disambiguate this question examining the contributions related to vocalization. The purpose of this research is to investigate the influence singing during melodic dictation can have over this activity, and to observe if this strategy contributes in a differentiated way for subjects in different development stages. An experimental study was conducted collectively with 68 undergraduates, which were divided in groups, one that was instructed to sing during dictation taking, and another that was instructed to stay in silence. Data collected were furthermore divided in sub-groups according to participants’ study time. The results show that singing hinders the dictation performance, especially in students with less musical experience, because it deconcentrates and disturbs the individuals in the same room. Although, we suggest instructors to not discourage vocalization, and to recommend students to do it outside the classroom until they develop inner singing. Our study, however, counted on a reduced number of subjects. Future research with an increased number of participants could give rise to different conclusions.

No abstract

No abstract

Entre 2003 e 2018, o Brasil viveu quadros socioeconômicos opostos. Até 2013/14, a economia seguiu crescendo, os indicadores socioeconômicos melhoraram, e muito disso graças aos investimentos do setor de petróleo e gás natural. Dentro desse, os investimentos da Petrobras em desenvolvimento tecnológico e de novas fronteiras exploratórias se destacaram como um propulsor. No entanto, a partir de 2014, uma somatória de fatores promoveu uma reviravolta nesse período virtuoso da economia nacional. Baseado nesse setor energético, o objetivo deste trabalho é esclarecer tais cenários.Palavras-chave: Petrobras; Geoeconomia; Crise.PETROBRAS’ ROLE IN THE BRAZILIAN ECONOMY (2003/2018): RISE AND FALL Abstract: Between 2003 and 2018, Brazil experienced opposing socioeconomic conditions. Until 2013/14, the economy continued to grow, socioeconomic indicators improved, and much of this was driven by investments in the oil and natural gas sector headed by Petrobras. Within these, investments in technological development to make the new exploratory frontier for the pre-salt feasible stood out. In this sector, the geoeconomic performance of the Brazilian government, making Petrobras the protagonist with a new regulatory framework for exploration and reinforcing the Local Content Policy (PCL), in addition to stimulating investments in a large number of complementary sectors, made the state company gain even more prominence on the world market. However, as of 2014, the sum of domestic and international factors brought about a turnaround in this virtuous period. Deeply affected by Operation Lava Jato, by the sharp devaluation of oil in the international market between 2014 and 2016, Petrobras had its direction radically changed, especially in the governments of Michel Temer and Jair Bolsonaro. Since then, dealing with a new management philosophy, it has been reducing its investments and having privatized exploration fields, segments and subsidiaries. In this scenario, stagnant growth and even a reduction in GDP, rising unemployment, currency devaluation, an increase in the concentration of wealth and political instability are latent in the country. Thus, based on the analysis of recent reports and articles, the objective of this paper is to clarify these two moments and show how Petrobras and the oil and natural gas sector are at the center of the recent political and socioeconomic events in Brazilian society.Keywords: Petrobras; Geoeconomics; Crisis.   EL PAPEL DE PETROBRAS EN LA ECONOMÍA BRASILEÑA (2003/2018): SUBIDA Y BAJADA Resumen: Entre 2003 y 2018, Brasil experimentó condiciones socioeconómicas opuestas. Hasta 2013/14, la economía siguió creciendo, los indicadores socioeconómicos mejoraron y gran parte de esto fue impulsado por inversiones en el sector de petróleo y gas natural - encabezado por Petrobras. Entre ellas, ganan relieve las inversiones en desarrollo tecnológico para viabilizar la nueva frontera exploratoria del presal. En este sector, el desempeño geoeconómico del gobierno brasileño (haciendo de Petrobras la protagonista con un nuevo marco regulatorio para la exploración y reforzando la Política de Contenido Local - PCL), además de estimular inversiones en un gran número de sectores complementarios, hizo que la empresa estatal ganara aún más protagonismo en el mercado mundial. Sin embargo, a partir de 2014, la suma de elementos nacionales e internacionales impulsó un vuelco en este período virtuoso. Profundamente afectada por la “Operación Lava Jato”, por la fuerte devaluación del petróleo en el mercado internacional entre 2014 y 2016, Petrobras cambió radicalmente su rumbo, especialmente en los gobiernos de Michel Temer y Jair Bolsonaro. Desde entonces, con una nueva filosofía de gestión, ha reducido sus inversiones y privatizando campos, segmentos y sucursales de exploración. En este contexto, el estancamiento del crecimiento e incluso una reducción del PIB, el aumento del desempleo, la devaluación de la moneda, un aumento en la concentración de la riqueza y la inestabilidad política están latentes en el país. Así, a partir del análisis de informes y artículos recientes, el objetivo de este trabajo es esclarecer estos dos momentos y mostrar como Petrobras y el sector de petróleo y gas natural están en el centro de los recientes acontecimientos políticos y socioeconómicos de la sociedad brasileña.Palabras clave: Petrobras; Geoeconomía; Crisis.

A partir do conceito de intolerância pela ambiguidade, este estudo de caso, originado de duas observações não estruturadas, avaliou duas situações distintas no contexto educacional. Ambas envolveram estados de confronto cognitivo estabelecidos por intermédio de enfrentamentos conceituais, os quais predispunham uma aluna do segundo ano do Ensino Fundamental I e a outra estudante de Música a exporem-se a condições de escolha. Tais circunstâncias tiveram como objetivo principal refletir sobre a aprendizagem significativa a partir da teoria ausubeliana. As contribuições permitiram compreender os motivos pelos quais a intolerância pela ambiguidade estabeleceu condições conflitantes nos sujeitos e o quanto a aprendizagem [musical] significativa é fundamental para que o aprendiz alcance patamares cognitivos superiores.