Widespread nanoflare variability detected with Hinode/XRT in a solar active region

It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun's hot corona, but whether they are the explanation for most of the multi-million degree plasma has been a matter of ongoing debate. We here present evidence that nanoflares are widespread in an active region observed by the X-Ray Telescope on-board the Hinode mission. The distributions of intensity fluctuations have small but important asymmetries, whether taken from individual pixels, multi-pixel subregions, or the entire active region. Negative fluctuations (corresponding to reduced intensity) are greater in number but weaker in amplitude, so that the median fluctuation is negative compared to a mean of zero. Using MonteCarlo simulations, we show that only part of this asymmetry can be explained by Poisson photon statistics. The remainder is explainable with a tendency for exponentially decreasing intensity, such as would be expected from a cooling plasma produced from a nanoflare. We suggest that nanoflares are a universal heating process within active regions.Comment: 26 pages, 7 figure

Artistas "nacional-estrangeiros" na vanguarda sul-americana (Segall e Xul Solar)

The article compares and contrasts the artistic and professional formations of Laser Segall and Xul Solar abroad, with emphasis on the vicissitudes of their social histories, models of artistic learning in Europe and the aesthetic responses discernable in their output after establishing themselves in their respective art markets in Brazil and Argentina.O artigo confronta os itinerários de formação artística e profissional de Lasar Segall e Xul Solar no exterior, com ênfase nas vicissitudes de sua história social, nos modelos de aprendizagem artística na Europa e nas respostas estéticas reconhecíveis em sua produção plástica após a fixação de ambos nos mercados de arte, respectivamente, no Brasil e na Argentina

As duas mortes do poeta

Escrutínio da análise da poesia de Manuel Bandeira em livro clássico de Davi Arrigucci Jr., com ênfase em poemas que mesclam materiais da experiência pessoal a circunstâncias políticas incidentes sobre a trajetória e a visão de mundo do escritor.Brief appraisal of Davi Arrigucci Jr. classic book on Manuel Bandeira’s poetry, emphasizing poemas which entangle materials from personal experience and political circumstances related to the writer’s career and worldview

A recepção de Pierre Bourdieu no Brasil: Circunstâncias e Mediadores

O texto a seguir advém da Aula Magna do Programa de Pós-Graduação em Sociologia da Universidade Federal do Paraná, ministrada pelo autor em agosto de 2019

Experiência social e imaginário literário nos livros de estréia dos modernistas em São Paulo

O artigo busca correlacionar os livros de estréia da primeira geração de modernistas em São Paulo às experiências sociais desses letrados, com ênfase no impacto exercido pelas circunstâncias de crise e mudança que afetaram de perto a trajetória de suas famílias, pela formação escolar e universitária, bem como pelas oportunidades de iniciativa e de investimento nos diversos gêneros e frentes da atividade intelectual e artística, num momento estratégico de definição de seus projetos intelectuais como autores, prensados entre veleidades criativas, impulsos doutrinários, aventuras amorosas e a prestação de serviços políticos e culturais aos dirigentes oligárquicos.The article seeks to view the São Paulo generation of modernist writers' first published books from the standpoint of their social experiences, emphasizing the impact due to the circumstances surrounding the crisis and change of their families trajectories, to their scholarly training and education, as well as to their initiatives and investments in the several genres and domains of intellectual and artistic activity, in a strategic moment of definition of their intellectual projects as authors, immersed in creative dreams, doctrinal crushes, amorous encounters and the political and cultural services they used to render to the ruling politicians

As tradições do mecenato europeu nos campos das artes cênicas, da música e de rádio-televisão

A despeito das diferenças substanciais no tocante ao volume de verbas destinadas à área artística e cultural, ao perfil organizacional das agências públicas incumbidas da alocação e gestão desses fundos, ao peso diferencial da iniciativa privada e às orientações doutrinárias e prioridades práticas em termos de política cultural, a maioria dos governos europeus instituiu no pós-guerra um aparato administrativo na área cultural, destinando-lhe um montante apreciável de recursos. Este trabalho compara o investimento de países europeus nos campos das artes cênicas, da música e de radiotelevisão

An X-ray characterization of the central region of the SNR G332.5-5.6

We present an X-ray analysis of the central region of supernova remnant (SNR) G332.5-5.6 through an exhaustive analysis of XMM-Netwon observations with complementary infrared observations. We characterize and discuss the origin of the observed X-ray morphology, which presents a peculiar plane edge over the west side of the central region. The morphology and spectral properties of the X-ray supernova remnant were studied using a single full frame XMM-Newton observation in the 0.3 to 10.0 keV energy band. Archival infrared WISE observations at 8, 12 and 24 \mu m were also used to investigate the properties of the source and its surroundings at different wavelengths. The results show that the extended X-ray emission is predominantly soft (0.3-1.2 keV) and peaks around 0.5 keV, which shows that it is an extremely soft SNR. X-ray emission correlates very well with central regions of bright radio emission. On the west side the radio/X-ray emission displays a plane-like feature with a terminal wall where strong infrared emission is detected. Our spatially resolved X-ray spectral analysis confirms that the emission is dominated by weak atomic emission lines of N, O, Ne, and Fe, all of them undetected in previous X-ray studies. These characteristics suggest that the X-ray emission is originated in an optically thin thermal plasma, whose radiation is well fitted by a non-equilibrium ionization collisional plasma (VNEI) X-ray emission model. Our study favors a scenario where G332.5-5.6 is expanding in a medium with an abrupt density change (the wall), likely a dense infrared emitting region of dust on the western side of the source.Comment: 7 pages, 5 figures and 2 tables. Accepted for publication in A&

Circuit modeling of a MEMS varactor including dielectric charging dynamics

Electrical models for MEMS varactors including the effect of dielectric charging dynamics are not available in commercial circuit simulators. In this paper a circuit model using lumped ideal elements available in the Cadence libraries and a basic Verilog-A model, has been implemented. The model has been used to simulate the dielectric charging in function of time and its effects over the MEMS capacitance value.Peer ReviewedPostprint (published version