The Si + SO2 collision and an extended network of neutral–neutral reactions between silicon and sulphur bearing species

International audienceThe Si + SO2 reaction is investigated to verify its impact on the abundances of molecules with astrochemical interest, such as SiS, SiO, SO, and others. According to our results Si(3P) and SO2 react barrierlessly yielding only the monoxides SO and SiO as products. No favourable pathway has been found leading to other products, and this reaction should not contribute to SiS abundance. Furthermore, it is predicted that SiS is stable in collisions with O2, and that S(3P) + SiO2 and O(3P)+OSiS will also produce SO + SiO. Using these results and gathering further experimental and computational data from the literature, we provide an extended network of neutral-neutral reactions involving Si- and S-bearing molecules. The effects of these reactions were examined in a protostellar shock model, using the NAUTILUS gas-grain code. This consisted in simulating the physicochemical conditions of a shocked gas evolving from (i) primeval cold core, (ii) the shock region itself, (iii) and finally the gas bulk conditions after the passage of the shock. Emphasizing on the cloud ages and including systematically these chemical reactions, we found that [SiS/H2] can be of the order of ~10-8 in shocks that evolves from clouds of t = 1 × 106 yr, whose values are mostly affected by the SiS + O $\longrightarrow$SiO + S reaction. Perspectives on further models along with observations are discussed in the context of sources harbouring molecular outflows

Endocardite infecciosa com apresentação inicial de abdome agudo

Paciente de 35 anos de idade foi atendido em Serviço de Emergência com seis horas de dor em fossa ilíaca direita e febre. Feita hipótese diagnóstica de apendicite aguda e realizada laparotomia exploradora. com apendicectomia. O paciente retornou ao hospital três dias após alta hospitalar. prostrado. febril. com alteração de fala. diminuição de nível de consciência e com hemiparesia completa à esquerda. CT scan de crânio e punção de líquor normal. RMN de encéfalo revelou aspectos compatíveis com AVC isquêmico vertebro-basilar. Ecocardiograma transesofágico demonstrou vegetação em valva aórtica e insuficiência aórtica moderada e hemoculturas foram positivas para Enterococcus bovis

Liberalização, vulnerabilidade financeira e instabilidade: algumas considerações sobre a economia brasileira Liberalization, financial vulnerability and instability: an analysis of the Brazilian economy

O artigo analisa a economia brasileira e sua vulnerabilidade externa (no período recente) a partir do referencial teórico de Minsky (1982, 1982b e 1986).Observa-se a tendência recorrente de ampliação da vulnerabilidade e o movimento cíclico dessa tendência não associada a regimes cambiais específicos, mas ampliada pela falta de controles cambiais. Nota-se, também, que o aprofundamento da vulnerabilidade externa da economia brasileira deve-se, sobretudo, ao comportamento da conta financeira, que compensou, com sobras, os resultados positivos obtidos pela balança comercial. Tais elementos conduzem a observação de uma tendência à ampliação da instabilidade nas esferas financeira e real dessa economia.<br>The paper analyses the Brazilian economy and its external vulnerability based on Minsky's theoretical approach. The continuous tendency increasing vulnerability and its cyclical movement, independent of the exchange rate regime, is observed. The paper points out that this tendency has been, in recent periods, mainly associated with the behaviour of the financial account, which compensated for the positive results of the country's balance of trade. All of these elements lead to the observation of an increased tendency towards increasing instability regarding the financial and real spheres of the Brazilian economy