Sem tela, sem pincel, sem tinta

Este trabalho é um dos desdobramentos da busca por uma maneira de apresentar as idéias geradas pela apropriação dasformas do conjunto de algumas taças de cristal quebradas. É um dos resultados de uma vasta experimentação de ações quevisam ressignificar estes objetos que perderam sua função utilitária, mas ganharam grande potencial artístico. Na verdade o trabalho consiste em estabelecer novas relações a estes objetos que saíram das suas significações, das suas relações de uso ehábito cotidiano

Spatially resolved XMM-Newton analysis and a model of the nonthermal emission of MSH 15-52

We present an X-ray analysis and a model of the nonthermal emission of the pulsar wind nebula (PWN) MSH15-52. We analyzed XMM-Newton data to obtain the spatially resolved spectral parameters around the pulsar PSRB1509-58. A steepening of the fitted power-law spectra and decrease in the surface brightness is observed with increasing distance from the pulsar. In the second part of this paper, we introduce a model for the nonthermal emission, based on assuming the ideal magnetohydrodynamic limit. This model is used to constrain the parameters of the termination shock and the bulk velocity of the leptons in the PWN. Our model is able to reproduce the spatial variation of the X-ray spectra. The parameter ranges that we found agree well with the parameter estimates found by other authors with different approaches. In the last part of this paper, we calculate the inverse Compton emission from our model and compare it to the emission detected with the H.E.S.S. telescope system. Our model is able to reproduce the flux level observed with H.E.S.S., but not the spectral shape of the observed TeV {\gamma}-ray emission.Comment: Accepted for publication in A&A, 9 pages, 15 figure

Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the PWN in G0.9+0.1

We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore we modeled its nonthermal emission in the X-ray and very high energy (VHE, E > 100 GeV) gamma-ray regime. Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral properties of G0.9+0.1 by calculating hardness ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations of the XMM-Newton telescope and extracted spectra of four annulus-shaped regions, centered on the region of brightest emission of the source. A radially symmetric leptonic model was applied in order to reproduce the observed X-ray emission of the inner part of the PWN. Using the optimized model parameter values obtained from the X-ray analysis, we then compared the modeled inverse Compton (IC) radiation with the published H.E.S.S. gamma-ray data. The spectral index within the four annuli increases with growing distance to the pulsar, whereas the surface brightness drops. With the adopted model we are able to reproduce the characteristics of the X-ray spectra. The model results for the VHE gamma radiation, however, strongly deviate from the H.E.S.S. data.Comment: 8 pages, 7 figures, accepted for publication in Astronomy & Astrophysic

A multi-wavelength study of the unidentified TeV gamma-ray source HESS J1626-490

HESS J1626-490, so far only detected with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes, could not be unambiguously identified with any source seen at lower energies. Therefore, we analyzed data from an archival XMM-Newton observation, pointed towards HESS J1626-490, to classify detected X-ray point-sources according to their spectral properties and their near-infrared counterparts from the 2MASS catalog. Furthermore, we characterized in detail the diffuse X-ray emission from a region compatible with the extended VHE signal. To characterize the Interstellar Medium surrounding HESS J1626-490 we analyzed $^{12}$CO(J=1-0) molecular line data from the NANTEN Galactic plane survey, HI data from the Southern Galactic Plane Survey and Spitzer data from the GLIMPSE and MIPSGAL surveys. None of the detected X-ray point sources fulfills the energetic requirements to be considered as the synchrotron radiation (SR) counterpart to the VHE source assuming an Inverse Compton (IC) emission scenario. We did not detect any diffuse X-ray excess emission originating from the region around HESS J1626-490 above the Galactic Background and the derived upper limit for the total X-ray flux disfavors a purely leptonic emission scenario for HESS J1626-490. We found a good morphological match between molecular and atomic gas in the -27km/s to -18km/s line-of-sight velocity range and HESS J1626-490. The cloud has a mass of 1.8$times 10^4$M$_{odot}$ and is located at a mean kinematic distance of $d$ = 1.8 kpc. Furthermore, we found a density depression in the HI gas at a similar distance which is spatially consistent with the SNR G335.2+00.1. We discuss various scenarios for the VHE emission, including the CO molecular cloud being a passive target for cosmic ray protons accelerated by the nearby SNR G335.2+00.1.Comment: 9 pages, 10 figures, A&A in press, updated to the final versio

Highly absorbed X-ray binaries in the Small Magellanic Cloud

Many of the high mass X-ray binaries (HMXRBs) discovered in recent years in our Galaxy are characterized by a high absorption, most likely intrinsic to the system, which hampers their detection at the softest X-ray energies. We have undertaken a search for highly-absorbed X-ray sources in the Small Magellanic Cloud (SMC) with a systematic analysis of 62 XMM-Newton SMC observations. We obtained a sample of 30 sources showing evidence for an equivalent hydrogen column density larger than 3x10^23 cm^-2. Five of these sources are clearly identified as HMXRBs: four were already known (including three X-ray pulsars) and one, XMM J005605.8-720012, reported here for the first time. For the latter, we present optical spectroscopy confirming the association with a Be star in the SMC. The other sources in our sample have optical counterparts fainter than magnitude ~16 in the V band, and many of them have possible NIR counterparts consistent with highly reddened early type stars in the SMC. While their number is broadly consistent with the expected population of background highly-absorbed active galactic nuclei, a few of them could be HMXRBs in which an early type companion is severely reddened by local material.Comment: 10 pages, 4 figures, 4 tables. Accepted for publication by Astronomy & Astrophysic

A Preference for Contralateral Stimuli in Human Object- and Face-Selective Cortex

Visual input from the left and right visual fields is processed predominantly in the contralateral hemisphere. Here we investigated whether this preference for contralateral over ipsilateral stimuli is also found in high-level visual areas that are important for the recognition of objects and faces. Human subjects were scanned with functional magnetic resonance imaging (fMRI) while they viewed and attended faces, objects, scenes, and scrambled images in the left or right visual field. With our stimulation protocol, primary visual cortex responded only to contralateral stimuli. The contralateral preference was smaller in object- and face-selective regions, and it was smallest in the fusiform gyrus. Nevertheless, each region showed a significant preference for contralateral stimuli. These results indicate that sensitivity to stimulus position is present even in high-level ventral visual cortex

Vacina contra a Esquistossomose Mansônica: uma Doença Negligenciada

Introduction: Schistosomiasis is a neglected, chronic and gradually debilitating parasitic disease that kills 200,000 people annually, according to the World Health Organization. Current strategies to control schistosomiasis are ineffective, and there is therefore a need to develop a vaccine against the disease. Objective: Show the main researches about vaccines development against schistosomiasis. Methodology: Narrative literature review conducted in October 2020, with selection of articles from 2012 in the Pubmed and Scielo databases, using "schistosomiasis" and "vaccine" as descriptors. The Clinical Trials platform was also consulted. Articles on vaccines against Schistosoma mansoni were included and articles referring exclusively to other species and other forms of treatment or prevention were excluded. Results: 26 articles were selected, with only two vaccines in human trials, Sm14 and Sm-TSP2. Sm14 (Brazil), with phase II completed, showed 50-68% protection against schistosomiasis. There is also Sm-TSP2 (USA), which showed protection of 65-69% in a phase I clinical trial. Besides these, some studies are still in the pre-clinical phase, such as Sm-p80 (USA), SmCB (Canada), SmCyp (Brazil), and chimeric vaccines (Iran) that combine antigens through immuno-informatics. There are also proposals for vaccine manufacturing that use nanotechnology and gold nanobastons in the production of adjuvants. Discussion: There are still many challenges to the development of these vaccines, such as the difficulty of mimicking the parasite genes, the difference in immune response between animal and human tests, the antivaccine movement, and the lack of interest from large pharmaceutical industries. Conclusion: There are two researches currently in clinical trials phase, Sm14 and Sm-TSP2, besides several others in pre-clinical phase. Although more studies are needed, this immunization approach could control the disease in the future, a problem evidenced in this work.Introdução: A esquistossomose é uma doença parasitária negligenciada, crônica e gradualmente debilitante, que mata 200 mil pessoas anualmente, segundo a Organização Mundial de Saúde. As estratégias atuais de controle da esquistossomose são ineficazes e há, portanto, necessidade de desenvolvimento de uma vacina contra a doença. Objetivo: Apresentar as principais pesquisas sobre o desenvolvimento de vacinas contra a esquistossomose. Metodologia: Revisão narrativa de literatura realizada em outubro de 2020, com a seleção de artigos a partir de 2012 nas bases de dados Pubmed e Scielo, utilizando os descritores “schistosomiasis” e “vaccine”. Foi consultada, também, a plataforma Clinical Trials. Foram incluídos artigos sobre vacinas contra Schistosoma mansoni e excluídos artigos referentes exclusivamente a outras espécies e outras formas de tratamento ou prevenção. Resultados: Foram selecionados 26 artigos, os quais apontam que há apenas duas vacinas em testes clínicos, a Sm14 e a Sm-TSP2. A Sm14 (Brasil), com fase II concluída, apresentou 50-68% de proteção contra a esquistossomose. A Sm-TSP2 (EUA), ainda em fase I, apresentou proteção de 65-69%. Além destas, alguns candidatos vacinais ainda estão na fase pré-clínica, como a Sm-p80 (EUA), a SmCB (Canadá), a SmCyp (Brasil) e vacinas quiméricas (Irã) que combinam antígenos através da imunoinformática. Há também propostas de fabricação de vacinas que usam nanotecnologia e nanobastões de ouro na produção de adjuvantes.  Discussão: Ainda há muitos desafios para o desenvolvimento dessas vacinas, como a dificuldade de isolar os genes do parasita, a diferença de resposta imune entre os testes em animais e humanos, o movimento antivacina e o desinteresse de grandes indústrias farmacêuticas. Conclusão: Há duas pesquisas em fase de ensaios clínicos atualmente, a Sm14 e a Sm-TSP2, além de várias outras em fase pré-clínica. Apesar de mais estudos serem necessários, essa estratégia de imunização poderia ser responsável pelo controle da doença no futuro, problemática evidenciada nesse trabalho