Investigando discursos e saberes experenciais dos professores de ciências sobre a interdisciplinaridade no ensino públicosecundário no rio grande do sul (Brasil)

Este trabalho em andamento visa compreender os discursos e os saberes dos professores de ciências de escolas públicas secundárias do Rio Grande do Sul (Brasil) sobre o tema interdisciplinaridade, sob uma visão de mundo sócio-histórica-cultural, pensadateorico-metodologicamente a partir darelação entre a linguagem e seu uso situado como proposto por Bakhtin, e a noção de saber docente e seus condicionantes articulados por Maurice Tardif. A necessidade desse estudoconfigurou-se a partir das mudanças curriculares operadas no Brasil, na direção de se institucionalizar a interdisciplinaridade na escola básica e das lacunas apresentadas pelas pesquisas da área. Estudos preliminares apontam para o fato de que os professoresentendem a interdisciplinaridade essencialmente como a discussão de um único tema tratado de maneira isolada por todas asdisciplinas

Star Formation and Clumps in Cosmological Galaxy Simulations with Radiation Pressure Feedback

Cosmological simulations of galaxies have typically produced too many stars at early times. We study the global and morphological effects of radiation pressure (RP) in eight pairs of high-resolution cosmological galaxy formation simulations. We find that the additional feedback suppresses star formation globally by a factor of ~2. Despite this reduction, the simulations still overproduce stars by a factor of ~2 with respect to the predictions provided by abundance matching methods for halos more massive than 5E11 Msun/h (Behroozi, Wechsler & Conroy 2013). We also study the morphological impact of radiation pressure on our simulations. In simulations with RP the average number of low mass clumps falls dramatically. Only clumps with stellar masses Mclump/Mdisk <= 5% are impacted by the inclusion of RP, and RP and no-RP clump counts above this range are comparable. The inclusion of RP depresses the contrast ratios of clumps by factors of a few for clump masses less than 5% of the disk masses. For more massive clumps, the differences between and RP and no-RP simulations diminish. We note however, that the simulations analyzed have disk stellar masses below about 2E10 Msun/h. By creating mock Hubble Space Telescope observations we find that the number of clumps is slightly reduced in simulations with RP. However, since massive clumps survive the inclusion of RP and are found in our mock observations, we do not find a disagreement between simulations of our clumpy galaxies and observations of clumpy galaxies. We demonstrate that clumps found in any single gas, stellar, or mock observation image are not necessarily clumps found in another map, and that there are few clumps common to multiple maps.Comment: 13 pages, 6 figures, submitted to MNRA

Avaliação da viabilidade celular e perfil de citocinas de linfócitos sanguíneos e esplênicos de ratos sépticos submetidos ao tratamento in vitro com taurina e cloramina taurina

Dissertação de Mestrado apresentada ao Programa de Pós-Graduação em Ciências da Saúde para obtenção do título de Mestre em Ciências da Saúde.Estudos estão buscando mecanismos de morte celular durante o curso da sepse, em que respostas pró-inflamatórias e anti-inflamatórias estão envolvidas na sua complexa fisiopatologia. Taurina (Tau) é um aminoácido abundante em polimorfomucleares (PMNs) que reage com ácido hipocloroso para formar o oxidante cloramina taurina (TauCl) em condições inflamatórias. Neste contexto, foi investigado potenciais interações entre linfócitos e TauCl em ratos submetidos à ligação e perfuração cecal (CLP), por meio de análise de viabilidade celular e perfil de secreção de citocinas (TNF-α, IFN-γ, IL-6, IL-17A, IL-23 e IL-10). Ratos adultos machos foram divididos em dois grupos (sham e CLP) e subsequentemente mortos 24 ou 120 horas após a indução da sepse para isolamento de linfócitos do sangue e do baço. Linfócitos (> 95,0% de pureza determinada por diferenciação com coloração de Giemsa) foram cultivados por 24 horas a uma concentração de 1x106 células/mL e ativadas com 2 μg/mL de concanavalina A (ConA). Após 24 horas, Tau e TauCl foram adicionadas a concentrações de 0,1, 0,2, 0,3, 0,4 e 0,5 (mM) por uma hora. Após este tempo, as células foram incubadas com MTT (500 μg/mL) por 3 horas para avaliar viabilidade celular e os sobrenatantes foram usados para determinar os níveis de citocinas. Células incubadas com Tau exibiram maior viabilidade do que as células incubadas com TauCl, em ambos tempos e órgãos. TauCl, por meio de relação dose-dependente, diminuiu a secreção de citocinas (TNF-α, IFN-γ, IL-6, IL-17A, IL-23 e IL-10) quando comparadas às células não incubadas. Estes achados mostram um possível comprometimento na função de linfócitos promovido pelo efeito de TauCl, correlacionado com a imunossupressão e morte celular características dos estágios de sepse.Studies are researching immune cell death mechanisms during the course of sepsis in response to pro-inflammatory and anti-inflammatory mediators that are involved in its pathophysiology. Taurine (Tau) is an abundant amino acid in polymorponuclear leucocytes (PMN) that reacts with hypochlorous acid to form taurine chloramine (TauCl) under inflammatory conditions. In this context, we investigated potential interactions between lymphocytes and TauCl in rats submitted to cecal ligation and perforation (CLP), analyzing cell viability and cytokine secretion profile (TNF-α, IFN-γ, IL-6, IL-17A, IL-23 and IL-10). Adult male rats were divided in two groups (sham and CLP) and then were killed 24 or 120 hours after sepsis induction to isolate lymphocytes from blood and spleen. Lymphocytes (> 95,0% purity determined by differentiation with Giemsa staining) were cultured for 24 hours at a concentration of 1x106 cells/mL and activated by 2 μg/mL concanavalin A (Con-A). After 24 hours, Tau and TauCl were added at concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5 (mM) for 1 hour. After this time, cells were incubated with MTT (500 μg/mL) for 3 hours to evaluate cell viability and supernatants were used to determine cytokines levels. Cells incubated with Tau exhibited better viability than those incubated with TauCl, in both time and organs. TauCl, in a time and dose-dependent ratio, decreased cytokines secretion (TNF-α, IFN-γ, IL-6, IL-17A, IL-23 and IL-10) when compared to untreated cells. These findings show a possible impairment in lymphocytes function promoted by TauCl, correlated with immunosuppression and cell death characteristic of the late stages of sepsis

New Image Statistics for Detecting Disturbed Galaxy Morphologies at High Redshift

Testing theories of hierarchical structure formation requires estimating the distribution of galaxy morphologies and its change with redshift. One aspect of this investigation involves identifying galaxies with disturbed morphologies (e.g., merging galaxies). This is often done by summarizing galaxy images using, e.g., the CAS and Gini-M20 statistics of Conselice (2003) and Lotz et al. (2004), respectively, and associating particular statistic values with disturbance. We introduce three statistics that enhance detection of disturbed morphologies at high-redshift (z ~ 2): the multi-mode (M), intensity (I), and deviation (D) statistics. We show their effectiveness by training a machine-learning classifier, random forest, using 1,639 galaxies observed in the H band by the Hubble Space Telescope WFC3, galaxies that had been previously classified by eye by the CANDELS collaboration (Grogin et al. 2011, Koekemoer et al. 2011). We find that the MID statistics (and the A statistic of Conselice 2003) are the most useful for identifying disturbed morphologies. We also explore whether human annotators are useful for identifying disturbed morphologies. We demonstrate that they show limited ability to detect disturbance at high redshift, and that increasing their number beyond approximately 10 does not provably yield better classification performance. We propose a simulation-based model-fitting algorithm that mitigates these issues by bypassing annotation.Comment: 15 pages, 14 figures, accepted for publication in MNRA

Protein 14-3-3 eta is essential for normal meiotic spindle assembly in mouse eggs

The 14-3-3 proteins constitute a family of conserved, acidic proteins in a variety of organisms, regulating important intracellular events including cell cycle control, apoptosis, signal transduction and embryonic development. However, little is known about the functions of 14-3-3 in mammalian reproduction. There are seven mammalian isoforms of 14-3-3 (beta, gamma, epsilon, eta, zeta, tau/theta and sigma) encoded by different genes. We previously reported accumulation and co-localization of a specific isoform of 14-3-3, namely 14-3-3 eta, in the region of meiotic spindle apparatus in mouse eggs. To determine the role of 14-3-3 eta, we microinjected mouse oocytes with a translation-blocking morpholino oligonucleotide to knock down the expression of 14-3-3 eta mRNA. Overnight incubation of the morpholino-injected oocytes followed by in vitro maturation revealed absence or impairment of meiotic spindle assembly in eggs, as shown by immunocytochemical staining of 14-3-3 eta and alpha-tubulin along with observation of chromosomes. Duolink In Situ Proximity Ligation Assay indicated marked interaction of 14-3-3 eta with alpha-tubulin in the region of meiotic spindle in all eggs examined, with prominent cortical accumulation about the spindles. These results suggest that 14-3-3 eta is necessary for normal meiotic spindle formation in mouse eggs. The study will help to elucidate the functional importance of 14-3-3 proteins in regulating mammalian oocyte maturation and female reproductive development