CoRoT observations of O stars: diverse origins of variability

Six O-type stars were observed continuously by the CoRoT satellite during a 34.3-day run. The unprecedented quality of the data allows us to detect even low-amplitude stellar pulsations in some of these stars (HD 46202 and the binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes and solar-like stochastic oscillations, both of importance to the asteroseismological modelling of O stars. Additional effects can be seen in the CoRoT light curves, such as binarity and rotational modulation. Some of the hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the presence of red-noise: we speculate that this is related to a sub-surface convection zone.Comment: 5 pages, 3 figures, conference paper. To be published in "Four decades of Research on Massive Stars", Astronomical Society of the Pacific. Eds. C. Robert, N. St-Louis and L. Drisse

Critical role of TLR2 and MyD88 for functional response of macrophages to a group IIA-Secreted phospholipase A2 from snake venom

artículo (arbitrado) -- Universidad de Costa Rica, Instituto de Investigaciones Clodomiro Picado. 2014The snake venom MT-III is a group IIA secreted phospholipase A2 (sPLA2) enzyme with functional and structural similarities with mammalian pro-inflammatory sPLA2s of the same group. Previously, we demonstrated that MT-III directly activates the innate inflammatory response of macrophages, including release of inflammatory mediators and formation of lipid droplets (LDs). However, the mechanisms coordinating these processes remain unclear. In the present study, by using TLR22/2 or MyD882/2 or C57BL/6 (WT) male mice, we report that TLR2 and MyD88 signaling have a critical role in MT-III-induced inflammatory response in macrophages. MT-III caused a marked release of PGE2, PGD2, PGJ2, IL-1b and IL-10 and increased the number of LDs in WT macrophages. In MT-III-stimulated TLR22/2 macrophages, formation of LDs and release of eicosanoids and cytokines were abrogated. In MyD882/2 macrophages, MT-III-induced release of PGE2, IL-1b and IL-10 was abrogated, but release of PGD2 and PGJ2 was maintained. In addition, COX-2 protein expression seen in MT-III-stimulated WT macrophages was abolished in both TLR22/2 and MyD882/2 cells, while perilipin 2 expression was abolished only in MyD882/2 cells. We further demonstrated a reduction of saturated, monounsaturated and polyunsaturated fatty acids and a release of the TLR2 agonists palmitic and oleic acid from MT-III-stimulated WT macrophages compared with WT control cells, thus suggesting these fatty acids as major messengers for MT-III-induced engagement of TLR2/MyD88 signaling. Collectively, our findings identify for the first time a TLR2 and MyD88-dependent mechanism that underlies group IIA sPLA2- induced inflammatory response in macrophages.This investigation was supported by research grants from FAPESP, Sao Paulo, Brazil (www.fapesp.br), grants 11/21341-5 and 10/06345-1, INCTTOX, Sao Paulo, Brazil (www.incttox.com.br), grant 573790/2008-6, CNPq PQ, Brazil (www.cnpq.br), grant 306920/2011-5, Brazil, Spanish Ministery of Science and Innovation, Spain (http://web.micinn.es/), grant BFU2010-18826.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Crystallization and preliminary X-ray diffraction analysis of a Lys49-PLA(2) homologue from Cerrophidion godmani venom.

Lys49-phospholipase A(2) (Lys49-PLA(2)) homologues damage membranes by a Ca2+-independent mechanism which does not involve catalytic activity. The myotoxic Lys-49 phospholipase myotoxin II from Cerrophidion (Bothrops) godmani has been crystallized, and X-ray diffraction data were collected to 2.8 Angstrom resolution. Preliminary analysis reveals the presence of one molecule in the asymmetric unit

CoRoT Observations of O Stars: Diverse Origins of Variability

Six O-type stars were observed continuously by the CoRoT satellite during a 34.3-day run. The unprecedented quality of the data allows us to detect even low-amplitude stellar pulsations in some of these stars (HD 46202 and the binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes and solar-like stochastic oscillations, both of importance to the asteroseismological modeling of O stars. Additional effects can be seen in the CoRoT light curves, such as binarity and rotational modulation. Some of the hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the presence of red-noise: we speculate that this is related to a sub-surface convection zone

Genetic analyses of aplastic anemia and idiopathic pulmonary fibrosis patients with short telomeres, possible implication of DNA-repair genes

Altres ajuts: Funded by one ACCI project from CIBERER and one grant to the FPI cohort from CIBERES.Background: Telomeres are nucleoprotein structures present at the terminal region of the chromosomes. Mutations in genes coding for proteins involved in telomere maintenance are causative of a number of disorders known as telomeropathies. The genetic origin of these diseases is heterogeneous and has not been determined for a significant proportion of patients. Methods: This article describes the genetic characterization of a cohort of patients. Telomere length was determined by Southern blot and quantitative PCR. Nucleotide variants were analyzed either by high-resolution melting analysis and Sanger sequencing of selected exons or by massive sequencing of a panel of genes. Results: Forty-seven patients with telomere length below the 10% of normal population, affected with three telomeropathies: dyskeratosis congenita (4), aplastic anemia (22) or pulmonary fibrosis (21) were analyzed. Eighteen of these patients presented known pathogenic or novel possibly pathogenic variants in the telomere-related genes TERT, TERC, RTEL1, CTC1 and ACD. In addition, the analyses of a panel of 188 genes related to haematological disorders indicated that a relevant proportion of the patients (up to 35%) presented rare variants in genes related to DNA repair or in genes coding for proteins involved in the resolution of complex DNA structures, that participate in telomere replication. Mutations in some of these genes are causative of several syndromes previously associated to telomere shortening. Conclusion: Novel variants in telomere, DNA repair and replication genes are described that might indicate the contribution of variants in these genes to the development of telomeropathies. Patients carrying variants in telomere-related genes presented worse evolution after diagnosis than the rest of patients analyzed

Nível do câmbio e crescimento econômico: teorias e evidências para países em desenvolvimento e emergentes Exchange rate levels and economic growth: theoretical analysis and empirical evidence for developing and emerging countries

O artigo analisa, teórica e empiricamente, a relação entre nível da taxa de câmbio e crescimento econômico nos países em desenvolvimento. Inicialmente, os objetivos da política cambial são discutidos, enfatizando sua importância como instrumento gerador de crescimento econômico. Dando continuidade, alguns canais de influência do nível da taxa de câmbio sobre o crescimento econômico são apontados: (i) os canais do investimento; (ii) da exportação dos bens não tradicionais; (iii) do desempenho do setor de bens comercializáveis; (iv) da compensação às falhas de mercado e falhas contratuais; e (v) de estímulo às elasticidades-renda das exportações. Na parte empírica, uma medida de subvalorização cambial é construí-da para 82 países em desenvolvimento entre 1980 e 2007. Essa medida é empregada para captar a relação entre taxa de câmbio desvalorizada e crescimento econômico. Os resultados indicam uma correlação positiva e significante entre a medida de subvalorização cambial construída e o crescimento econômico nos países que fazem parte da amostra.<br>The article analyses, theoretically and empirically, the relationship between exchange rate level and economic growth in emerging and developing countries. Firstly, the exchange rate policy objectives are discussed, emphasizing the importance of this policy to generate economic growth. Continuing, the article explores the channels through which exchange rates can affect economic growth, highlighting its stimulus to investment, export of non-traditional goods, productivity as well as its compensation to market failures and its stimulus to export income-elasticity. In the empirical part, a measure of exchange rate undervaluation based on Rodrik (2007) is built for 82 emerging and developing countries, between 1980 and 2007. This measure is used to investigate the relationship between devalued exchange rate and economic growth, by econometric techniques for panel data. The result of the estimations point out the positive correlation between undervalued exchange rate and economic growth, confirming the importance of the exchange rate as an instrument to promote economic growth and development

Taxa de juros e prêmio de risco: investigando a hipótese Bresser-Nakano para a economia brasileira, 1995-2005 Interest rate and the risk premium: Bresser-Nakano's hypothesis in the brazilian economy, 1995-2005

A proposta Bresser-Nakano deflagrou uma forte discussão sobre a política de juros no Brasil, suscitando uma série de críticas e contribuições para o seu aperfeiçoamento. Seu argumento central baseia-se na suposição de que o sentido da causalidade vai da taxa de juros para o prêmio de risco, e não o contrário. Com isso, a autoridade monetária, ao reduzi-la, promove um círculo virtuoso na economia, reduzindo o prêmio de risco e, através da taxa de câmbio, a própria inflação. Essa hipótese, no entanto, continua controversa e carece de estudos empíricos visando à sua verificação. O objetivo principal deste trabalho é investigar a sua validade para a economia brasileira nos últimos 10 anos de política monetária. Aplicando testes de causalidade de Granger, os resultados encontrados apóiam a hipótese Bresser-Nakano.<br>The Bresser-Nakano's proposal raised a wide discussion on the monetary policy in Brazil and several critiques were brought about as well as contributions for its improvement. Their main argument is based upon a causality relation that runs from interest rate to risk premium with a positive correlation. In this case a cut in the interest rate shifts down the risk premium, and could even reduce the price inflation by the exchange rate. This assumption is linked to others issues in financial integration in an open economy context. The traditional view is that the interest rate is determined by the interest rate parity condition and that the monetary authority has no autonomy to set different rates from those determined by the "capital's flows". An alternative approach defends that is possible to peg with wide autonomy the domestic interest rate, even in this context. The results endorse Bresser-Nakano's proposal and suggest it could be feasible for Brazilian real situation