Bardeen-Petterson effect and the disk structure of the Seyfert galaxy NGC 1068

VLBA high spatial resolution observations of the disk structure of the active galactic nucleus NGC 1068 has recently revealed that the kinematics and geometry of this AGN is well characterized by an outer disk of H2O maser emission having a compact milliarcsecond (parsec) scale structure, which is encircling a thin rotating inner disk surrounding a ~10^7 M_\sun compact mass, likely a black hole. A curious feature in this source is the occurrence of a misalignment between the inner and outer parts of the disk, with the galaxy's radio jet being orthogonal to the inner disk. We interpret this peculiar configuration as due to the Bardeen-Petterson effect, a general relativistic effect that warps an initially inclined (to the black hole equator) viscous disk, and drives the angular momentum vector of its inner part into alignment with the rotating black hole spin. We estimate the time-scale for both angular momenta to get aligned as a function the spin parameter of the Kerr black hole. We also reproduce the shape of the parsec and kiloparsec scale jets, assuming a model in which the jet is precessing with a period and aperture angle that decrease exponentially with time, as expected from the Bardeen-Petterson effect.Comment: 12 pages, 3 figures, accepted for publication in The Astrophysical Journa

Discovery of CH and OH in the -513 km s-1 Ejecta of Eta Carinae

The very massive star, Eta Carinae, is enshrouded in an unusual complex of stellar ejecta, which is highly depleted in C and O, and enriched in He and N. This circumstellar gas gives rise to distinct absorption components corresponding to at least 20 different velocities along the line-of-sight. The velocity component at -513 kms-1 exhibits very low ionization with predominantly neutral species of iron-peak elements. Our statistical equilibrium/photoionization modeling indicates that the low temperature (T = 760 K) and high density (n_H=10^7 cm^-3) of the -513 kms-1 component is conducive to molecule formation including those with the elements C and O. Examination of echelle spectra obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the confirms the model's predictions. The molecules, H_2, CH, and most likely OH, have been identified in the -513 kms-1 absorption spectrum. This paper presents the analysis of the HST/STIS spectra with the deduced column densities for CH, OH and C I, and upper limit for CO. It is quite extraordinary to see molecular species in a cool environment at such a high velocity. The sharp molecular and ionic absorptions in this extensively CNO- processed material offers us a unique environment for studying the chemistry, dust formation processes, and nucleosynthesis in the ejected layers of a highly evolved massive star.Comment: tentatively scheduled for the ApJ 1 September 2005, v630, 1 issu

Quebra de dormência em diásporos de teca (Tectona grandis L.f.).

Tectona grandis L.f. é uma essência florestal exótica de importância econômica e social para o Brasil. As mudas dessa espécie são produzidas através de diásporos constituídos dos frutos com endocarpo e mesocarpo rígidos. O objetivo do presente trabalho foi avaliar o efeito de métodos de quebra de dormência na germinação das sementes desta espécie. Para superar a dormência do endocarpo e mesocarpo, os diásporos de teca foram submetidos à imersão em água quente, imersão em ácido sulfúrico (33,5%) e imersão em água corrente. Os diásporos foram distribuídos em substrato constituído de areia, e o teste de germinação foi realizado em câmara de germinação com temperatura de 30 ºC, sob luz branca durante oito horas por dia. As avaliações foram feitas diariamente, durante 60 dias. O método de imersão dos diásporos em ácido sulfúrico por três minutos, foi o tratamento mais eficiente, apresentando 73% das sementes germinadas

Comportamento da Macrofauna edáfica em diferentes modelos de arborização de cafeeiro Robusta (Coffea canephora) em Rondônia.

O levantamento da fauna edáfica do solo é uma forma indicada de avaliar a viabilidade em função do manejo deste tipo de sistema. O objetivo deste trabalho foi fazer um levantamento da ocorrência da macrofauna do solo em 05 (dez) propriedades cultivadas com o café Robusta (Coffea canephora) arborizado no município de Rolim de Moura, localizado na região da Zona da Mata/RO em duas épocas diferentes. Na época chuvosa e seca, as Ordens com maiores frequência de ocorrência foram Hymenoptera, Araneae, Coleoptera, Dermaptera, Orthoptera, Isoptera, Acari, Lithobiomorpha, Diptera, Hemiptera. Através do índice de diversidade de Shannon identificou-se propriedades com maior estabilidade, principalmente quando houve maior diversidade de espécies florestais nos SAFs. O manejo dos SAFs, o clima, a diversidade de espécies florestais e o tamanho das áreas amostradas possivelmente influenciam a diversidade de Ordens da macrofauna

Observational evidence of spin-induced precession in active galactic nuclei

We show that it is possible to explain the physical origin of jet precession in active galactic nuclei (AGNs) through the misalignment between the rotation axes of the accretion disk and of the Kerr black hole. We apply this scenario to quasars, Seyfert galaxies and also to the Galactic Center black hole Sgr A*, for which signatures of either jet or disk precession have been found. The formalism adopted is parameterized by the ratio of the precession period to the black hole mass and can be used to put constraints to the physical properties of the accretion disk as well as to the black hole spin in those systems.Comment: 10 pages, 1 figure, accepted for publication in ApJ Letter

Origin of the complex radio structure in BAL QSO 1045+352

We present new more sensitive high-resolution radio observations of a compact broad absorption line (BAL) quasar, 1045+352, made with the EVN+MERLIN at 5 GHz. They allowed us to trace the connection between the arcsecond structure and the radio core of the quasar. The radio morphology of 1045+352 is dominated by a knotty jet showing several bends. We discuss possible scenarios that could explain such a complex morphology: galaxy merger, accretion disk instability, precession of the jet and jet-cloud interactions. It is possible that we are witnessing an ongoing jet precession in this source due to internal instabilities within the jet flow, however, a dense environment detected in the submillimeter band and an outflowing material suggested by the X-ray absorption could strongly interact with the jet. It is difficult to establish the orientation between the jet axis and the observer in 1045+352 because of the complex structure. Nevertheless taking into account the most recent inner radio structure we conclude that the radio jet is oriented close to the line of sight which can mean that the opening angle of the accretion disk wind can be large in this source. We also suggest that there is no direct correlation between the jet-observer orientation and the possibility of observing BALs.Comment: 8 pages, 3 figures, accepted for publication in Ap

Centaurus A: The Nearest Blazar?

Abstract. Centaurus A (NGC5128), at a distance of 3.4 Mpc is the nearest Active Galaxy, classified as a low luminosity Fanaroff-Riley class I object. Although the central source is completely obscured at optical wavelengths, VLBI studies at radio frequencies show an unresolved core and an asymmetric jet at sub-parsec scales. Kinematical studies of the jet components show subluminal expansion velocities, which together with the jet-counterjet intensity ratio implies that the jet direction forms a large angle with the line of sight (50 o to 80 o ). The nuclear emission is highly variable at all wavelengths, from radio to γ-rays. Single dish radio observations showed that the stronger, long duration outbursts (months to years) present a correlation at radio and X-rays, although it is not clear whether the emission mechanism is synchrotron radiation at both frequencies or if the inverse Compton process dominates at high energies. Moreover, no information is available about the correlation between the emission at these two frequencies at shorter timescales (days and hours), due to the lack of short term monitoring at radio frequencies. In this work we report 43 GHz monitoring of Cantaurus A at the Itapetinga Radio Observatory during the last year, with daily resolution during a three-month period. We found very large variations (factor of two) within a few days, which puts Centaurus A in the blazar category. These variations were superimposed to a continuous rise in flux density that lasted until the end of 2003, when it started a fast decline. No apparent correlation with the All Sky Monitor (ASM/RXTE) data was found at these short timescales

Study Of Irradiated Bothropstoxin-1 With 60co Gamma Rays: Immune System Behavior

Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.152216225(1998) Secretaria Nacional de Ações Básicas de Saúde: Acidentes Ofídicos Contribuição Ao Estudo Da Morbidade, , Brasil. Ministério da Saúde. Brasília: Ministério da Saúde2 volsCupo, P., Azevedo-Marques, M.M., Menezes, J.B., Hering, S.E., Reações de hipersensibilidade imediata após uso intravenoso de soros antivenenos: Valor prognóstico dos testes de sensibilidade (1991) Rev Inst Med Trop São Paulo, 33 (2), pp. 115-122Abib, H., Laraba-Djebari, F., Effects of60Co gamma radiation on toxicity and hemorrhagic, myonecrotic, and edema-forming activities of Cerastes cerastes venom (2003) Can J Physiol Pharmacol, 81 (12), pp. 1125-1130Zamuner, S.R., Cruz-Höfling, M.A., Corrado, A.P., Hyslop, S., Rodrigues-Simioni, L., Comparison of the neurotoxic and myotoxic effects of Brazilian Bothrops venoms and their neutralization by commercial antivenom (2004) Toxicon, 44 (3), pp. 259-271Camey, K.U., Velarde, D.T., Sanchez, E.F., Pharmacological characterization and neutralization of the venoms used in the production of Bothropic antivenom in Brazil (2002) Toxicon, 40 (5), pp. 501-509. , DOI 10.1016/S0041-0101(01)00245-8, PII S0041010101002458Oshima-Franco, Y., Leite, G.B., Silva, G.H., Cardoso, D.F., Hyslop, S., Giglio, J.R., Cruz-Höfling, Ma., Rodrigues-Simioni, L., Neutralization of the pharmacological effects of bothropstoxin-1 from Bothrops jararacussu (jararacuçu) venom by crotoxin antiserum and heparin (2001) Toxicon, 39 (10), pp. 1477-1485Butler, J., Hoey, B.M., Swallow, A.J., Radiation chemistry (1987) Annu Rep Prog Chem, 83, pp. 129-175Garrison, W.M., Reaction mechanisms in the radiolysis of peptides, polypeptides, and proteins (1987) Chem Rev, 87 (2), pp. 381-398Grosh, D.S., Hoopywood, L.E., (1979) Biological Effects of Radiation. 2nd Ed., , New York: Academic PressNascimento, N.D., Seebart, C.S., Francis, B., Rogero, J.R., Kaiser, I.I., Influence of ionizing radiation on crotoxin: Biochemical and immunological aspects (1996) Toxicon, 34 (1), pp. 123-131. , DOI 10.1016/0041-0101(95)00111-5Delves, P.J., Roitt, I.M., The immune system. First of two parts (2000) New England Journal of Medicine, 343 (1), pp. 37-49. , DOI 10.1056/NEJM200007063430107Janeway, C.A., Travers, P., Walport, M., Shlomchik, M.J., (2002) Imunobiologia: O Sistema Imune Na Saúde e Na Doença, 767p. , Porto Alegre: Editora ArtMedSpencer, P.J., Aird, S.D., Boni-Mitake, M., Nascimento, N., Rogero, J.R., A single-step purification of bothropstoxin-1 (1998) Brazilian Journal of Medical and Biological Research, 31 (9), pp. 1125-1127Harlow, E., Lane, D., (1988) Antibodies. A Laboratory Manual, 726p. , New York: Cold Sprig Harbor LaboratoryVitaliano, S.N., Silva, D.A.O., Ferreira, R.A., Bevilacqua, E., Mineo, J.R., Avaliação dos níveis de anticorpos IgG anti-Toxoplasma gondii em lobos-guará (Chrysocyon brachyurus) por meio de ensaios imunoenzimáticos utilizando conjugados homólogos, heterólogos e de afinidade (2005) Horizonte Cient, 1, pp. 1-18Moon, S., Song, K.B., Effect of gamma-irradiation on the molecular properties of ovalbumin and ovomucoid and protection by ascorbic acid (2001) Food Chemistry, 74 (4), pp. 479-483. , DOI 10.1016/S0308-8146(01)00166-2, PII S0308814601001662Baptista, J.A., Spencer, P.J., Oliveira, J.E., Casare, M.S., Nascimento, N., Immune response against antigens irradiated with60Co gamma rays (2006) J Radioanal Nuclear Chem, 269 (3), pp. 565-569Brewer, J.M., Richmond, J., Alexander, J., The demonstration of an essential role for macrophages in the in vivo generation of IgG2a antibodies (1994) Clin Exp Immunol, 97 (1), pp. 164-171Sprent, J., Surh, C.D., T cell memory (2002) Annual Review of Immunology, 20, pp. 551-579. , DOI 10.1146/annurev.immunol.20.100101.15192

STUDY OF IRRADIATED BOTHROPSTOXIN-1 WITH Co-60 GAMMA RAYS: IMMUNE SYSTEM BEHAVIOR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.152216225Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq