A Detection of Gas Associated with the M 31 Stellar Stream

Detailed studies of stellar populations in the halos of the Milky Way and the Andromeda (M 31) galaxies have shown increasing numbers of tidal streams and dwarf galaxies, attesting to a complicated and on-going process of hierarchical structure formation. The most prominent feature in the halo of M 31 is the Giant Stellar Stream, a structure ~4.5 degrees in extent along the sky, which is close to, but not coincident with the galaxy's minor axis. The stars that make up this stream are kinematically and chemically distinct from the other stars in the halo. Here, we present HST/COS high-resolution ultraviolet absorption spectra of three Active Galactic Nuclei sight lines which probe the M 31 halo, including one that samples gas in the main southwestern portion of the Giant Stream. We see two clear absorption components in many metal species at velocities typical of the M 31 halo and a third, blue-shifted component which arises in the stream. Photoionization modeling of the column density ratios in the different components shows gas in an ionization state typical of that seen in other galaxy halo environments and suggests solar to slightly super-solar metallicity, consistent with previous findings from stellar spectroscopy.Comment: 10 pages, 5 figures, accepted for publication in the Astrophysical Journa

O TEMPO DOS TRIBALISTAS: as juventudes líquidas traduzidas na música brasileira contemporânea

Este artigo analisa as letras de quatro músicas do grupo Tribalistas a partir dos conceitos de Modernidade Líquida (BAUMAN 2001) e das tribos urbanas (MAFFESOLI 1998) no contexto das juventudes contemporâneas. Para esta análise, também são utilizados dados quantitativos da pesquisa Os Jovens do Ensino Médio das Regiões das Hortênsias e Encosta da Serra. As canções analisadas contribuem para traduzir as condições e características das juventudes líquidas da pós-modernidade. Os jovens apresentam configurações de identidades múltiplas, com transições da infância e adolescência para a juventude – e depois para vida adulta –, variáveis de acordo com o contexto social de cada um.

LAÇO SOCIAL E TECNOLOGIA EM TEMPOS EXTREMOS: contribuições aos discursos de conveniência contemporâneos

Resenha crítica da coletânea Laço Social e Tecnologia em Tempos Extremos (Editora Sulina, 2020)

Apontamentos das lutas de poder na trajetória política do futebol brasileiro

In this paper I present historical moments in the formation of Brazilian football with the objective of marking and scoring intense power struggles, which configured themselves into offsets and displacements or socio-political-cul­tural transformations. The methodology used for this study was the bibliographic review through the recovery of historical facts with their sociological analysis. There were and it seems that there will always be power struggles in this cultural field and a mark of the identity of the Brazilians.Neste texto, apresento momentos históricos na constituição do futebol brasileiro com objetivo de marcar e pontuar intensas lutas de poder, que se configuraram em viradas, deslocamentos ou transformações sóciopolítico-culturais. A metodologia utilizada para este trabalho foi a revisão bibliográfica através da recuperação de fatos históricos, com a sua análise sociológica. Houve e parece que sempre haverá lutas de poder neste campo cultural e marco da identidade dos brasileiros

BAUMAN - UMA BIOGRAFIA: a trajetória identitária de um intelectual

Resenha do livro BAUMAN: UMA BIOGRAFI

Explicit Encoding of Multimodal Percepts by Single Neurons in the Human Brain

Different pictures of Marilyn Monroe can evoke the same percept, even if greatly modified as in Andy Warhol’s famous portraits. But how does the brain recognize highly variable pictures as the same percept? Various studies have provided insights into how visual information is processed along the ‘‘ventral pathway,’’ via both single-cell recordings in monkeys and functional imaging in humans. Interestingly, in humans, the same "concept" of Marilyn Monroe can be evoked with other stimulus modalities, for instance by hearing or reading her name. Brain imaging studies have identified cortical areas selective to voices and visual word forms. However, how visual, text, and sound information can elicit a unique percept is still largely unknown. By using presentations of pictures and of spoken and written names, we show that (1) single neurons in the human medial temporal lobe (MTL) respond selectively to representations of the same individual across different sensory modalities; (2) the degree of multimodal invariance increases along the hierarchical structure within the MTL; and (3) such neuronal representations can be generated within less than a day or two. These results demonstrate that single neurons can encode percepts in an explicit, selective, and invariant manner, even if evoked by different sensory modalities

Correlação entre fatores de experiência linguística bilíngue e controle inibitório

Não há ainda uma resposta definitiva para o debate quanto à existência da vantagem cognitiva bilíngue nas funções do controle executivo proposta por parte da literatura (BIALYSTOK; BARAC, 2013). Uma revisão bibliográfica pós-2011 (PAAP; JOHNSON; SAWI, 2015) identificou que a maioria das pesquisas que buscam por uma vantagem bilíngue nas funções executivas retorna resultados nulos e que, portanto, tal vantagem não existiria ou apareceria somente em circunstâncias específicas que ainda não foram determinadas. A presente pesquisa exploratória teve por objetivo investigar alguns fatores que podem contribuir para a caracterização dessas circunstâncias específicas. Mais especificamente, este estudo correlacionou fatores de experiência linguística bilíngue com o controle inibitório, uma das três grandes subdivisões das funções executivas (MIYAKE; FRIEDMAN, 2012), medido através do efeito Simon. Descobriu-se que o efeito Simon (medido em tempo de reação), ao contrário do que indicaria a lógica encontrada na literatura da área, se correlacionou positivamente com a quantidade de mixing (mistura de duas ou mais línguas ao se comunicar) que os bilíngues efetuavam. Houve também correlação negativa entre o tempo de reação no efeito Simon e a idade de aquisição média de uma L3. Dessa forma, quanto mais mixing os bilíngues efetuaram e quanto mais cedo eles começaram a utilizar uma L3, menor a sua capacidade de controle inibitório (maior efeito Simon). Tais evidências vão em encontro às concepções acerca da relação entre fatores de experiência linguística e funções executivas. No entanto, são contrárias à literatura anterior, que preveria que o mixing estaria associado a um efeito Simon menor.There is yet no definite answer to the debate regarding the existence of a bilingual cognitive advantage in the executive control functions as proposed by part of the literature (BIALYSTOK; BARAC, 2013). A post-2011 review (PAAP; JOHNSON; SAWI, 2015) found that most studies looking for a bilingual advantage in the executive functions yield null results and that, therefore, such advantage may not exist or may appear in specific circumstances that have yet to be determined. This exploratory research aims to investigate some factors that can contribute to the characterization of these specific circumstances. More specifically, the study correlated bilingual linguistic experience factors to inhibitory control, one of the three main subdivisions of the executive functions (MIYAKE; FRIEDMAN, 2012), as measured by the Simon effect. It was found that the Simon effect (measured in response time), differently from what would be expected from reading the literature, correlated negatively to the amount of mixing (of two or more languages while speaking) the bilinguals performed. There was also a negative correlation between response time in the Simon effect and the age of acquisition of a third language. This means that the more mixing the bilinguals performed and the earlier they started using a third language, the lower their inhibitory control ability (bigger Simon effect) was. Such evidences follow the conceptions about the relationship between linguistic experience and executive functions. However, they go in the opposite direction than the one proposed by the previous literature, which would predict mixing to be associated with a smaller Simon effect

Sparse Representation in the Human Medial Temporal Lobe

Recent experiments characterized individual neurons in the human medial temporal lobe with remarkably selective, invariant, and explicit responses to images of famous individuals or landmark buildings. Here, we used a probabilistic analysis to show that these data are consistent with a sparse code in which neurons respond in a selective manner to a small fraction of stimuli

A Single-Neuron Correlate of Change Detection and Change Blindness in the Human Medial Temporal Lobe

Observers are often unaware of changes in their visual environment when attention is not focused at the location of the change [1,2,3,4]. Because of its rather intriguing nature, this phenomenon, known as change blindness, has been extensively studied with psychophysics [5,6,7] as well as with fMRI [8,9,10,11]. However, whether change blindness can be tracked in the activity of single cells is not clear. To explore the neural correlates of change detection and change blindness, we recorded from single neurons in the human medial temporal lobe (MTL) during a change-detection paradigm. The preferred pictures of the visually responsive units elicited significantly higher firing rates on the attended trials when subjects correctly identified a change (change detection) compared to the unattended trials when they missed it (change blindness). On correct trials, the firing activity of individual units allowed us to predict the occurrence of a change, on a trial-by-trial basis, with 67% accuracy. In contrast, this prediction was at chance for incorrect, unattended trials. The firing rates of visually selective MTL cells thus constitute a neural correlate of change detection