An MHD study of SN 1006 and determination of the ambient magnetic field direction

In this work we employ an MHD numerical code to reproduce the morphology observed for SN 1006 in radio synchrotron and thermal X-ray emission. We introduce a density discontinuity, in the form of a flat cloud parallel to the Galactic Plane, in order to explain the NW filament observed in optical wavelengths and in thermal X-rays. We compare our models with observations. We also perform a test that contrasts the radio emitting bright limbs of the SNR against the central region, finding additional support to our results. Our main conclusion is that the most probable direction of the ambient magnetic field is on average perpendicular to the Galactic Plane.Comment: 7 pages, 5 figures, accepted by MNRA

3D MHD simulation of polarized emission in SN 1006

We use three dimensional magnetohydrodynamic (MHD) simulations to model the supernova remnant SN 1006. From our numerical results, we have carried out a polarization study, obtaining synthetic maps of the polarized intensity, the Stokes parameter $Q$, and the polar-referenced angle, which can be compared with observational results. Synthetic maps were computed considering two possible particle acceleration mechanisms: quasi-parallel and quasi-perpendicular. The comparison of synthetic maps of the Stokes parameter $Q$ maps with observations proves to be a valuable tool to discern unambiguously which mechanism is taking place in the remnant of SN 1006, giving strong support to the quasi-parallel model.Comment: 6 pages, 4 figures, accepted by MNRA

On the sensitivity of extrasolar mass-loss rate ranges: HD 209458b a case study

We present a 3D hydrodynamic study of the effects that different stellar wind conditions and planetary wind structures have on the calculated Ly-$\alpha$ absorptions produced during the transit of HD 209458b. Considering a range of stellar wind speeds $\sim$[350-800] km s$^{-1}$, coronal temperature $\sim$[3-7] $\times10^{6}$ K and two values of the polytropic index $\Gamma$ $\sim$[1.01-1.13], while keeping fixed the stellar mass loss rate, we found a that a $\dot M_p$ range between $\sim$[3-5] $\times 10^{10}$g s$^{-1}$ give account for the observational absorption in Ly-$\alpha$ measured for the planetary system. Also, several models with anisotropic evaporation profiles for the planetary escaping atmosphere were carried out, showing that both, the escape through polar regions and through the night side yields larger absorptions than an isotropic planetary wind

Photo-ionization of planetary winds: case study HD209458b

Close-in hot Jupiters are exposed to a tremendous photon flux that ionizes the neutral escaping material from the planet leaving an observable imprint that makes them an interesting laboratory for testing theoretical models. In this work we present 3D hydrodynamic simulations with radiation transfer calculations of a close-in exoplanet in a blow-off state. We calculate the Ly-$\alpha$ absorption and compare it with observations of HD 209458b an previous simplified model results.Our results show that the hydrodynamic interaction together with a proper calculation of the photoionization proccess are able to reproduce the main features of the observed Ly-$\alpha$ absorption, in particular at the blue-shifted wings of the line. We found that the ionizing stellar flux produce an almost linear effect on the amount of absorption in the wake. Varying the planetary mass loss rate and the radiation flux, we were able to reproduce the $10\%$ absorption observed at $-100~\mathrm{km~s^{-1}}$.Comment: 9 pages, 6 figure

Alveolar Echinococcosis of the Liver in an Adult with Human Immunodeficiency Virus Type-1 Infection

Abstract. : We describe a patient with human immunodeficiency virus type-1 (HIV) infection and alveolar echinococcosis (AE) with a focus on two messages. Despite being severely immunocompromised over years the patient exhibited a long-term asymptomatic course of AE. This is in clear contrast to reports describing accelerated courses of AE in immunocompromised patients. The patient had therapeutic mebendazole drug levels with only 1/10 of the normal drug dose. He was co-treated with protease inhibitors for his HIV infection. These drugs are known as strong inhibitors of cytochrome P450 3A4 (CYP3A4)-dependent metabolism. We speculate that benzimidazoles and protease inhibitors interfere at the CYP3A4-level. The first report of co-infection of HIV and accelerated AE was in a young girl with an extremely low CD4 cell count and an abrogated lymphoproliferative responsiveness to parasite antigen stimulation. Since the CD4 cell count in our patient remained in the range of 27-150 cells/µl, we speculate that there was a critical threshold of immunosupression for constraining AE. Initial treatment with albendazole for AE added to the current highly active antiretroviral treatment (HAART), and suppressive toxoplasmosis therapy became complicated by pancytopenia. After full recovery of the bone marrow, mebendazole was introduced with a new HAART and the previously prescribed toxoplasmosis maintenance therapy. Surprisingly, efficient mebendazole levels were achieved with an uncommonly low dose. These observations suggest that the benzimidazoles, albendazole and mebendazole, may interact with protease inhibitors, which are known for their strong inhibition of the CYP3A