Structure and kinematics of the molecular spiral arms in M51

Mapping of the CO(1-0) emission from the spiral galaxy was made with the Onsala 20 m antenna. The observations show that the emission is considerably enhanced in spiral arms which appear to originate as intense ridges of emission about 1 kpc from the nucleus. One of the main objectives for the 1986 observations was to study the variations of the tangential velocity component of molecular gas across a spiral arm. The radial velocity was found to have a velocity shift similar to that predicted by the density wave theory. The present (1986) observations of the inner southern spiral arm of M51 show that the tangential velocity component also behaves in a way which conforms with the density wave model. The molecular arms were compared with the H alpha ionized gas arms of Tully (1974) and it was found that the ionized gas appears to have its maximum intensity slightly outside the molecular arm

H2O line mapping at high spatial and spectral resolution - Herschel observations of the VLA1623 outflow

Apart from being an important coolant, H2O is known to be a tracer of high-velocity molecular gas. Recent models predict relatively high abundances behind interstellar shockwaves. The dynamical and physical conditions of the H2O emitting gas, however, are not fully understood yet. We aim to determine the abundance and distribution of H2O, its kinematics and the physical conditions of the gas responsible for the H2O emission. The observed line profile shapes help us understand the dynamics in molecular outflows. We mapped the VLA1623 outflow, in the ground-state transitions of o-H2O, with the HIFI and PACS instruments. We also present observations of higher energy transitions of o-H2O and p-H2O obtained with HIFI and PACS towards selected outflow positions. From comparison with non-LTE radiative transfer calculations, we estimate the physical parameters of the water emitting regions. The observed water emission line profiles vary over the mapped area. Spectral features and components, tracing gas in different excitation conditions, allow us to constrain the density and temperature of the gas. The H2O emission originates in a region where temperatures are comparable to that of the warm H2 gas (T\gtrsim200K). Thus, the H2O emission traces a gas component significantly warmer than the gas responsible for the low-J CO emission. The H2O column densities at the CO peak positions are low, i.e. N(H2O) \simeq (0.03-10)x10e14 cm-2. The H2O abundance with respect to H2 in the extended outflow is estimated at X(H2O)<1x10e-6, significantly lower than what would be expected from most recent shock models. The H2O emission traces a gas component moving at relatively high velocity compared to the low-J CO emitting gas. However, other dynamical quantities such as the momentum rate, energy and mechanical luminosity are estimated to be the same, independent of the molecular tracer used, CO or H2O.Comment: 14 pages, 13 figures, 4 table

Ellipsoidal universe in the brane world

We study a scenario of the ellipsoidal universe in the brane world cosmology with a cosmological constant in the bulk . From the five-dimensional Einstein equations we derive the evolution equations for the eccentricity and the scale factor of the universe, which are coupled to each other. It is found that if the anisotropy of our universe is originated from a uniform magnetic field inside the brane, the eccentricity decays faster in the bulk in comparison with a four-dimensional ellipsoidal universe. We also investigate the ellipsoidal universe in the brane-induced gravity and find the evolution equation for the eccentricity which has a contribution determined by the four- and five-dimensional Newton's constants. The role of the eccentricity is discussed in explaining the quadrupole problem of the cosmic microwave background.Comment: 15 pages, 1 figure, Version 3, references added, contents expande

Cosmological constraints combining H(z), CMB shift and SNIa observational data

Recently H(z) data obtained from differential ages of galaxies have been proposed as a new geometrical probe of dark energy. In this paper we use those data, combined with other background tests (CMB shift and SNIa data), to constrain a set of general relativistic dark energy models together with some other models motivated by extra dimensions. Our analysis rests mostly on Bayesian statistics, and we conclude that LCDM is at least substantially favoured, and that braneworld models are less favoured than general relativistic ones.Comment: 17 pages, 11 figures; improved discussion, new figures, updated to match published versio

The effect of inhomogeneities on the distance to the last scattering surface and the accuracy of the CMB analysis

The standard analysis of the CMB data assumes that the distance to the last scattering surface can be calculated using the distance-redshift relation as in the Friedmann model. However, in the inhomogeneous universe, even if =0, the distance relation is not the same as in the unperturbed universe. This can be of serious consequences as a change of distance affects the mapping of CMB temperature fluctuations into the angular power spectrum. In addition, if the change of distance is relatively uniform no new temperature fluctuations are generated. It is therefore a different effect than the lensing or ISW effects which introduce additional CMB anisotropies. This paper shows that the accuracy of the CMB analysis can be impaired by the accuracy of calculation of the distance within the cosmological models. Since this effect has not been fully explored before, to test how the inhomogeneities affect the distance-redshift relation, several methods are examined: the Dyer-Roeder relation, lensing approximation, and non-linear Swiss-Cheese model. In all cases, the distance to the last scattering surface is different than when homogeneity is assumed. The difference can be as low as 1% and as high as 80%. Excluding extreme cases, the distance changes by about 20-30%. Since the distance to the last scattering surface is set by the position of the CMB peaks, in order to have a good fit, the distance needs to be adjusted. After correcting the distance, the cosmological parameters change. Therefore, a not properly estimated distance to the last scattering surface can be a major source of systematics. This paper shows that if inhomogeneities are taken into account when calculating the distance then models with positive spatial curvature and with \Omega_\Lambda ~ 0.8-0.9 are preferred. The \Lambda CDM model in most cases, is at odds with the current data.Comment: 18 pages, 6 figure

Testing the DGP model with ESSENCE

We use the recent supernova data set from the ESSENCE collaboration combined with data from the Supernova Legacy Survey and nearby supernovae to test the DGP brane world model and its generalisations. Combination of this data with a flatness prior and the position of the peak of the CMB disfavours the DGP model slightly. Inclusion of the baryon acoustic peak from the Sloan Digital Sky Survey increase the tension of the DGP model with the data, although it is not clear how self consistent this procedure would be without a re-analysis of the survey data in the framework of the DGP cosmology. Generalisations of the DGP model are tested and constraints on relevant parameters obtained.Comment: Minor corrections, clarifications and references added. Published in JCA

Unknown cadaver: its historical and academic importance for human anatomy

Observações feitas na maioria das universidades brasileiras estrangeiras, e, inclusive, em algumas sobre o aspecto acadêmico do uso de cadáveres humanos como principal material que suporta e direciona a Anatomia Humana nos cursos da área da saúde, traz, dentre outras conclusões de caráter didático, uma questão de formação, muito mais importante do que uma simples questão de, apenas, informação universitária. Há de se concordar que, mesmo com o fabuloso avanço tecnológico e suas possibilidades, nossas universidades hoje, primam mais pela questão informativa do que propriamente pela formativa, ao passo que ternos consciência de que o ser humano necessita igualmente de ambas. Em consequência disto, o principal objetivo deste trabalho é enfocar o valor acadêmico do cadáver, evidenciando sua importante relação histórica, sem a qual a Anatomia não existiria e, certamente, a Medicina também não teria ultrapassado suas fronteiras limitadas do passado. O fato de ser este um trabalho realizado em uma universidade brasileira é revestido de responsabilidade e determinação em tentar colocar a figura do cadáver humano no lugar, no qual ele realmente deva estar, não apenas como simples material e instrumento de ensino da anatomia, mas também como lição de vida através da morte, criando Ciência e Arte, valorizando sua importância no contexto artístico e religioso, fatores estes imprescindíveis para a formação sócio-cultural humana. Por outro lado, este estudo com abordagem de caráter acadêmico, tornou-se dificil quanto a bibliografia específica, tendo sido feita portanto, quase toda a sua pesquisa em tratados históricos e anatômicos e, apenas alguns poucos trabalhos sobre a importância do cadáver para a Anatomia. Neste trabalho, procuramos usar ilustrações e figuras como documentação de caráter informativo e estético. Assim sendo, para uma abordagem mais ampla, o cadáver foi discutido desde sua relação histórica e acadêmica, até os dias de hoje, onde ainda se enfrenta, quase, as mesmas dificuldades do passado, no que diz respeito as questões de doação de corpo e órgãos, que deixaram de ser apenas institucionalmente acadêmicas, para ser mais rigorosamente sociais, segundo as Leis vigentes.Observations about most of brazilian universities and, even some of foreign ones, concerning the academic aspects of the use of human cadavers or corpses as the principal human anatomy method of studying, which maintain the basic courses of Health Sciences Field, that is, the cadaver or corpse himself should be also seen as a noble and magnificent way of transmitting knowledge and human values. Indeed, these observations have been showing some didactic results concerning much more, a matter of individual information than individual formation itself. Nowadays, this happens because scholasticism, differently from the past, seems to emphasize quantitative rather than qualitative teaching philosophy. We must admit that, even living in a technological era and being able to take advantages of its possibilities, our universities today emphasize much more the information itself than individual formation of our professionals of tomorrow, while we know that the individual needs both, equally. Therefore, the main goal of this work is focusing the academic importance of the human cadaver or corpse as a practical studying material, which is related to the own history of the practical Anatomy and consequently Medicine and, if it were not because of that, Medicine itself would not have gone beyond its limited frontiers of the past. On the other hand, the inedited academic meaning of this work became too difficult to come abroad, because of its specific bibliographical lack among scientific publications and, that's why, most of its text was found in the old Health Sciences, books and texts in general. However, another particular characteristic of this work is the great number of pictures and illustrations, which enrich the present text and substitute the lack of similar works' bibliography, In this work, the corpse is seen, from his historical relation and academical aspects the to present circumstances, where the need for anatomical study faces the same difficulties of the past, when Vesalius opened the way to the study of Human Anatomy, but as we know many years passed before Anatomy could be taught to medical students by means of dissection, the only method by which physicians and surgeons can fully acquire this knowledge. The scarcity of anatomical material seemed to be over at the present time, when laws were just enacted, such as specified law for the use of the corpse, organs and structures donation, that unfortunately did not solve the old and permanent problem, such as the absence of corpses for anatomical dissections.BV UNIFESP: Teses e dissertaçõe