[Cervix uteri lesions and human papiloma virus infection (HPV): detection and characterization of DNA/HPV using PCR (polymerase chain reaction)]

Tit. em Português: Lesões do Colo Uterino e Infecção pelo Vírus do Papiloma Humano (HPV) Detecção e tipificação do ADN/HPV por PCR (Reacção de amplificação enzimática)The prevalence of human papillomavirus (HPV) genotypes was estimated by the polymerase chain reaction (PCR), in archival paraffin was embedded tissues. The case group consisted of 84 women aged 21-67 years (mean, 40 years) who were referred to the Department of Gynaecology (Oncology Centre, Coimbra) with citopathologically abnormal smears. This group was selected from a population of women who had undergone a screening programme (1990/94) in Central Region of Portugal. All these patients (n = 84) had a colposcopic directed cervical biopsy. HPV detection and typing was performed by the PCR method in the Department of Virology (National Health Care Institute, Lisbon). The prevalence of DNA/HPV found, concerning all epithelial cervical lesions studied and classified as squamous intra-epithelial lesions (SIL) and cervical cancer was 97.8%. On the basis of the data presented in this study, it was estimated that there was a statistically significant prevalence of low risk HPV types (HPV 6/11) in low grade SIL, 83.3%, and a statistically significant prevalence of high risk HPV types (HPV 16,18,31,33,51) in high grade SIL, 58.4%, as well as cervical cancer lesions in 100%. We conclude that there was a statistically significant difference between women with low and high grade SIL for HPV infection, with low and high risk HPV types, respectively. The risk factors for cervical cancer investigated (age at first sexual intercourse, multiple sexual partners, parity, use of oral contraceptives) were not associated to statistically significant differences concerning low grade SIL and high grade SIL. The clinical and therapeutic procedures were evaluated for the same five years (1990/94). It may be concluded that there would be no significant difference in clinical procedure for high grade lesions and cervical cancer, in which the treatment had been frequently radical (cone biopsies, simple or radical hysterectomy) and in which the HPV infection persisted frequently and was associated to high risk types (HPV 16 in 50% of these cases). On the other hand, it may be concluded that HPV detection in cervical biopsies, especially for low grade SIL lesions, which were evaluated in this study with a more conservative procedure (clinical evaluation only, punch biopsies, loop diathermy, CO2 laser vaporisation, cone biopsies), could identify women with high risk HPV types who might be at risk of developing dysplasia and cervical cancer

Vorticity production through rotation, shear and baroclinicity

In the absence of rotation and shear, and under the assumption of constant temperature or specific entropy, purely potential forcing by localized expansion waves is known to produce irrotational flows that have no vorticity. Here we study the production of vorticity under idealized conditions when there is rotation, shear, or baroclinicity, to address the problem of vorticity generation in the interstellar medium in a systematic fashion. We use three-dimensional periodic box numerical simulations to investigate the various effects in isolation. We find that for slow rotation, vorticity production in an isothermal gas is small in the sense that the ratio of the root-mean-square values of vorticity and velocity is small compared with the wavenumber of the energy-carrying motions. For Coriolis numbers above a certain level, vorticity production saturates at a value where the aforementioned ratio becomes comparable with the wavenumber of the energy-carrying motions. Shear also raises the vorticity production, but no saturation is found. When the assumption of isothermality is dropped, there is significant vorticity production by the baroclinic term once the turbulence becomes supersonic. In galaxies, shear and rotation are estimated to be insufficient to produce significant amounts of vorticity, leaving therefore only the baroclinic term as the most favorable candidate. We also demonstrate vorticity production visually as a result of colliding shock fronts.Comment: 9 pages, 10 figures, Accepted for publication in A&

Deep XMM-Newton observations of the northern disc of M31. I. Source catalogue

We carried out new observations of two fields in the northern ring of M31 with XMM-Newton with two exposures of 100 ks each and obtained a complete list of X-ray sources down to a sensitivity limit of ~7 x 10^34 erg s^-1 (0.5 - 2.0 keV). The major objective of the observing programme was the study of the hot phase of the ISM in M31. The analysis of the diffuse emission and the study of the ISM is presented in a separate paper. We analysed the spectral properties of all detected sources using hardness ratios and spectra if the statistics were high enough. We also checked for variability. We cross-correlated the source list with the source catalogue of a new survey of the northern disc of M31 carried out with Chandra and Hubble (Panchromatic Hubble Andromeda Treasury, PHAT) as well as with other existing catalogues. We detected a total of 389 sources, including 43 foreground stars and candidates and 50 background sources. Based on the comparison to the Chandra/PHAT survey, we classify 24 hard X-ray sources as new candidates for X-ray binaries (XRBs). In total, we identified 34 XRBs and candidates and 18 supernova remnants (SNRs) and candidates. Three of the four brightest SNRs show emission mainly below 2 keV, consistent with shocked ISM. The spectra of two of them also require an additional component with a higher temperature. The SNR [SPH11] 1535 has a harder spectrum and might suggest that there is a pulsar-wind nebula inside the SNR. We find five new sources showing clear time variability. We also studied the spectral properties of the transient source SWIFT J004420.1+413702, which shows significant variation in flux over a period of seven months (June 2015 to January 2016) and associated change in absorption. Based on the likely optical counterpart detected in the Chandra/PHAT survey, the source is classified as a low-mass X-ray binary.Comment: Accepted for publication in A&

The Turbulent Interstellar Medium: Insights and Questions from Numerical Models

"The purpose of numerical models is not numbers but insight." (Hamming) In the spirit of this adage, and of Don Cox's approach to scientific speaking, we discuss the questions that the latest generation of numerical models of the interstellar medium raise, at least for us. The energy source for the interstellar turbulence is still under discussion. We review the argument for supernovae dominating in star forming regions. Magnetorotational instability has been suggested as a way of coupling disk shear to the turbulent flow. Models make evident that the unstable wavelengths are very long compared to thermally unstable wavelengths, with implications for star formation in the outer galaxy and low surface brightness disks. The perennial question of the factors determining the hot gas filling factor in a SN-driven medium remains open, in particular because of the unexpectedly strong turbulent mixing at the boundaries of hot cavities seen in the models. The formation of molecular clouds in the turbulent flow is also poorly understood. Dense regions suitable for cloud formation clearly form even in the absence of self-gravity, although their ultimate evolution remains to be computed.Comment: 9 pages in astro-ph version, four reduced resolution color figures, to be published in How Does the Galaxy Work?, eds. E. J. Alfaro, E. P\'erez, J. Franco (Kluwer, Dordrecht

Local Star formation triggered by SN shocks in magnetized diffuse neutral clouds

In this work, considering the impact of a SNR with a neutral magnetized cloud we derived analytically a set of conditions which are favorable for driving gravitational instability in the cloud and thus star formation. We have built diagrams of the SNR radius, versus the cloud density, that constrain a domain in the parameter space where star formation is allowed. The diagrams are also tested with fully 3-D MHD simulations involving a SNR and a self-gravitating cloud and we find that the numerical analysis is consistent with the results predicted by the diagrams. While the inclusion of a homogeneous magnetic field approximately perpendicular to the impact velocity of the SNR with an intensity ~1 $mu$G results only a small shrinking of the star formation triggering zone in the diagrams, a larger magnetic field (~10 $mu$G) causes a significant shrinking, as expected. Applications of the diagrams to a few regions of our own galaxy have revealed that star formation in those sites could have been triggered by shock waves from SNRs. Finally, we have evaluated the effective star formation efficiency for this sort of interaction and found that it is smaller than the observed values in our own Galaxy (sfe ~0.01-0.3). This result is consistent with previous work in the literature and also suggests that the mechanism presently investigated, though very powerful to drive structure formation, supersonic turbulence and eventually, local star formation, does not seem to be sufficient to drive global star formation in normal star forming galaxies, not even when the magnetic field in the neutral clouds is neglected. (abridged)Comment: 19 pages, 13 figures, accepted for pubblication in MNRA

XMM-Newton observations of a superbubble in N 158 in the LMC

Aims: We study the diffuse X-ray emission observed in the field of view of the pulsar B 0540-69 in the Large Magellanic Cloud (LMC) by XMM-Newton. We want to understand the nature of this soft diffuse emission, which coincides with the superbubble in the HII region N 158, and improve our understanding of the evolution of superbubbles. Methods: We analyse the XMM-Newton spectra of the diffuse emission. Using the parameters obtained from the spectral fit, we perform calculations of the evolution of the superbubble. The mass loss and energy input rates are based on the initial mass function (IMF) of the observed OB association inside the superbubble. Results: The analysis of the spectra shows that the soft X-ray emission arises from hot shocked gas surrounded by a thin shell of cooler, ionised gas. We show that the stellar winds alone cannot account for the energy inside the superbubble, but the energy release of 2 - 3 supernova explosions in the past ~1 Myr provides a possible explanation. Conclusions: The combination of high sensitivity X-ray data, allowing spectral analysis, and analytical models for superbubbles bears the potential to reveal the evolutionary state of interstellar bubbles, if the stellar content is known.Comment: 7 pages. Accepted for publication in A&

Mushroom-Shaped Structures as Tracers of Buoyant Flow in the Galactic Disk

Recent HI emission observations of the Southern Galactic hemisphere have revealed a mushroom-like structure extending from z=-70 to -450 pc, composed of a stem and a cap. Similar structures occur in three-dimensional simulations of a dynamic galactic disk driven by isolated and clustered supernovae. Using these simulations, we show that hot gas in the Galactic disk that is not evacuated through chimneys expands into the cooler gas of the thick disk, forming mushroom-shaped structures. This new class of objects traces buoyant flow of hot gas into the thick disk.Comment: Accepted for publication in ApJ Letters. Latex manuscript, 3 figures (4 postsript files

Hydrodynamical simulations of Galactic fountains II: evolution of multiple fountains

Using 3D hydrodynamical simulations, we studied in detail the fountain flow and its dependence with several factors, such as the Galactic rotation, the distance to the Galactic center, and the presence of a hot gaseous halo. We have considered the observed size-frequency distribution of young stellar clusters within the Galaxy in order to appropriately fuel the multiple fountains in our simulations. The present work confirms the localized nature of the fountain flows: the freshly ejected metals tend to fall back close to the same Galactocentric region where they are delivered. Therefore, the fountains do not change significantly the radial profile of the disk chemical abundance. The multiple fountains simulations also allowed to consistently calculate the feedback of the star formation on the halo gas. Finally, we have also considered the possibility of mass infall from the intergalactic medium and its interaction with the clouds that are formed by the fountains. Though our simulations are not suitable to reproduce the slow rotational pattern that is typically observed in the halos around the disk galaxies, they indicate that the presence of an external gas infall may help to slow down the rotation of the gas in the clouds and thus the amount of angular momentum that they transfer to the coronal gas, as previously suggested in the literature.Comment: 19 pages, 18 figures, accepted for publication in MNRA

The structure of self-gravitating clouds

To study the interaction of star-formation and turbulent molecular cloud structuring, we analyse numerical models and observations of self-gravitating clouds using the Delta-variance as statistical measure for structural characteristics. In the models we resolve the transition from purely hydrodynamic turbulence to gravitational collapse associated with the formation and mass growth of protostellar cores. We compare models of driven and freely decaying turbulence with and without magnetic fields. Self-gravitating supersonic turbulence always produces a density structure that contains most power on the smallest scales provided by collapsed cores as soon as local collapse sets in. This is in contrast to non-self-gravitating hydrodynamic turbulence where the Delta-variance is dominated by large scale structures. To detect this effect in star-forming regions observations have to resolve the high density contrast of protostellar cores with respect to their ambient molecular cloud. Using the 3mm continuum map of a star-forming cluster in Serpens we show that the dust emission traces the full density evolution. On the contrary, the density range accessible by molecular line observations is insufficient for this analysis. Only dust emission and dust extinction observations are able to to determine the structural parameters of star-forming clouds following the density evolution during the gravitational collapse.Comment: 12 pages, 9 figures, A&A in pres

Kinematics of diffuse ionized gas in the disk halo interface of NGC 891 from Fabry-P\'erot observations

The properties of the gas in halos of galaxies constrain global models of the interstellar medium. Kinematical information is of particular interest since it is a clue to the origin of the gas. Here we report observations of the kinematics of the thick layer of the diffuse ionized gas in NGC 891 in order to determine the rotation curve of the halo gas. We have obtained a Fabry-P\'erot data cube in Halpha to measure the kinematics of the halo gas with angular resolution much higher than obtained from HI 21 cm observations. The data cube was obtained with the TAURUS II spectrograph at the WHT on La Palma. The velocity information of the diffuse ionized gas extracted from the data cube is compared to model distributions to constrain the distribution of the gas and in particular the halo rotation curve. The best fit model has a central attenuation tau_H-alpha=6, a dust scale length of 8.1 kpc, an ionized gas scale length of 5.0 kpc. Above the plane the rotation curve lags with a vertical gradient of -18.8 km/s/kpc. We find that the scale length of the H-alpha must be between 2.5 and 6.5 kpc. Furthermore we find evidence that the rotation curve above the plane rises less steeply than in the plane. This is all in agreement with the velocities measured in the HI.Comment: A&A, in press. 13 pages, 19 figure