The chemical history of the nearest starburst galaxy – IC10

AbstractThe irregular dwarf galaxy IC10 is located within the Local Group (LG) at a distance of 750 kpc. Although several studies have revealed the existence of stellar populations with a broad range of ages, its star formation history (SFH) and age-metallicity (AM) relationship remain quite unknown. In this contribution we present our spectroscopic investigation of 15 H ii regions, 9 planetary nebulae (PNe) and 1 symbiotic star –so far the farthest known symbiotic binary. Our main goal is to reconstruct the SFH of IC10 and to constrain its AM relationship using young and intermediate-age stars. The direct availability of the electron temperature in our emission-line spectra allows an accurate determination of the IC10 metallicity map at two different epochs. We find a non-homogeneous distribution of metals at both epochs, but similar average abundances for the two analyzed populations. The derived AM relationship shows a little global enrichment, which is interpreted as due to the loss of metals by supernovae winds and to differential gas outflows. Our results bring strong observational constraints to the chemical enrichment history of IC10, the formation of dwarf irregular galaxies and the evolution of the LG as well

Ethanol-water pulp enzymatic pretreatment: chemical and FTIR-PCA analyses

Pulps obtained from ethanol/water cooking of sugarcane bagasse were treated at different times using xylanase enzyme obtained from Thermomyces lanuginosus IOC-4145 or commercially (Cartazyme HS, Sandoz Products Ltd.). The enzyme dosage was 18 IU per g of dry pulp and the time varied from 4 h to 12 h. When xylanase from T. lanuginosus was used, the kappa number and viscosity improved independently of the processing time used (4 h, 8 h, and 12 h). After chemical evaluation, the obtained pulps were classified using Fourier Transformed Infra-Red Spectroscopy and Principal Component Analysis. The results showed that the first three principal components explained more than 90 % of the total variance of the pulp spectra.FAPESP; CNPq

Extragalactic Planetary Nebulae: tracers of the chemical evolution of nearby galaxies

The study of the chemical composition of Planetary Nebulae in external galaxies is of paramount importance in the fields of stellar evolution and of the chemical enrichment history of galaxies. In the last years a number of spectroscopic studies with 6-8m-class telescopes have been devoted to this subject improving our knowledge of, among other, the time-evolution of the radial metallicity gradient in disk galaxies, the chemical evolution of dwarf galaxies, and the stellar evolution at low metallicity.Comment: 8 pages, 4 figures, Invited Review to IAU Symposium 283, "Planetary Nebulae: an Eye to the Future", Tenerife, 25-29 July 201

When Shape Matters: correcting the ICFs to derive the chemical abundances of bipolar and elliptical PNe

The extraction of chemical abundances of ionised nebulae from a limited spectral range is usually hampered by the lack of emission lines corresponding to certain ionic stages. So far, the missing emission lines have been accounted for by the ionisation correction factors (ICFs), constructed under simplistic assumptions like spherical geometry by using 1-D photoionisation modelling. In this contribution we discuss the results (Goncalves et al. 2011, in prep.) of our ongoing project to find a new set of ICFs to determine total abundances of N, O, Ne, Ar, and S, with optical spectra, in the case of non-spherical PNe. These results are based on a grid of 3-D photoionisation modelling of round, elliptical and bipolar shaped PNe, spanning the typical PN luminosities, effective temperatures and densities. We show that the additional corrections --to the widely used Kingsburgh and Barlow (1994) ICFs-- are always higher for bipolars than for ellipticals. Moreover, these additional corrections are, for bipolars, up to: 17% for oxygen, 33% for nitrogen, 40% for neon, 28% for argon and 50% for sulphur. Finally, on top of the fact that corrections change greatly with shape, they vary also greatly with the central star temperature, while the luminosity is a less important parameter.Comment: Oral contribution (4 pages, 2 figures) to IAU Symposium 283: "Planetary Nebulae: An Eye to the Future" held in Puerto de la Cruz, Tenerife, Spain in July 25th-29th 201

Active methodology: Flipped classroom and its practices in Basic Education

Este estudo propõe uma investigação sobre a metodologia ativa chamada "sala de aula invertida" e suas práticas na educação básica, problematizando como estas ocorrem. Na introdução, justificamos a importância da temática como foco investigativo. Metodologicamente, trata-se de um estudo qualitativo, utilizou-se de uma revisão bibliográfica em dissertações produzidas em âmbito nacional que contemplaram os temas metodologia ativa, sala de aula invertida, sendo que a busca dos dados foi realizada no período de 2014 a 2018, na base de dados da CAPES de teses e dissertações a partir dos descritores "metodologia ativa" e "sala de aula inversa." Os resultados preliminares apontaram 36 dissertações, desse total 8 atenderam aos critérios de inclusão sendo 06 de mestrado scrito sensu e 02 de mestrado profissional, as demais foram excluídas por não estabelecer um diálogo adequado e em consonância com a temática. As conclusões apontaram que ao se pensar na sala de aula invertida como uma prática devemos considerar o papel fundamental da tecnologia, bem como a mudança de papel do professor que se torna o mediador do processo e entendemos que a sala de aula invertida se enquadra como uma estratégia de ensino-aprendizagem. Todavia, a educação básica demanda novos formatos de interação discente-docente-discente e ao que tudo indica as metodologias ativas estão conquistando espaço, mas ainda requerem apropriação por parte dos professores e demais envolvidos nos processos acadêmicosThis study proposes an investigation about the active methodology called "inverted classroom" and its practices in basic education, problematizing how they occur. In the introduction, we justify the importance of the topic as an investigative focus. Methodologically, it is a qualitative study, it was used a bibliographical review in dissertations produced in a national scope that included the active methodology methodology, inverted classroom, and the search of the data was carried out in the period from 2014 to 2018, in the database of the thesis and dissertations captions from the descriptors "active methodology" and "inverse classroom." Preliminary results indicated 36 dissertations, of which 8 met the inclusion criteria, being 6 masters scrito sensu and 02 professional masters, the others were excluded because they did not establish an adequate dialogue and in line with the theme. The conclusions pointed out that when thinking of the inverted classroom as a practice we must consider the fundamental role of technology as well as the changing role of the teacher who becomes the mediator of the process and we understand that the inverted classroom fits like a teaching-learning strategy. However, basic education demands new formats of student-teacher-student interaction, and it seems that active methodologies are gaining space, but still require appropriation by teachers and others involved in academic processe

Low-ionization structures in planetary nebulae -- II. Densities, temperatures, abundances and excitation of 6 PNe

Here we present the spatially resolved study of six Galactic planetary nebulae (PNe), namely IC 4593, Hen 2-186, Hen 2-429, NGC 3918, NGC 6543 and NGC 6905, from intermediate-resolution spectra of the 2.5 m Isaac Newton Telescope and the 1.54 m Danish telescope. The physical conditions (electron densities, N$_{e}$, and temperatures, T$_{e}$), chemical compositions and dominant excitation mechanisms for the different regions of these objects are derived, in an attempt to go deeper on the knowledge of the low-ionization structures (LISs) hosted by these PNe. We reinforce the previous conclusions that LISs are characterized by lower (or at most equal) N$_{e}$ than their associated rims and shells. As for the T$_{e}$, we point out a \textit{possible} different trend between the N and O diagnostics. T$_e$[NII] does not show significant variations throughout the nebular components, whereas T$_e$[OIII] appears to be slightly higher for LISs. The much larger uncertainties associated with the T$_e$[OIII] of LISs do not allow robust conclusions. Moreover, the chemical abundances show no variation from one to another PN components, not even contrasting LISs with rims and shells, as also found in a number of other works. By discussing the ionization photon flux due to shocks and stellar radiation, we explore the possible mechanisms responsible for the excitation of LISs. We argue that the presence of shocks in LISs is not negligible, although there is a strong dependence on the orientation of the host PNe and LISs