Context. Red super-giant (RSG) stars exhibit significant mass loss through a slow and dense wind. They are often considered to be the more massive counter-parts of Asymptotic Giant Branch (AGB) stars. While the AGB mass-loss is linked to their strong pulsations, the RSG are often only weakly variable. This raises the question whether their wind-driving mechanism and the dust composition in the ...

We present a method to estimate the total gas column density, dust-to-gas and dust-tometal ratios of distant galaxies from rest-frame optical spectra. The technique exploits the sensitivity of certain optical lines to changes in depletion of metals onto dust grains and uses photo-ionization models to constrain these physical ratios along with the metallicity and dust column density. We compare ...

Received ; accepted – 2 – ABSTRACT Embedded Young Stellar Objects (YSO) in dense interstellar clouds is treated self-consistently to understand their spectral energy distributions (SED). Radiative transfer calculations in spherical geometry involving the dust as well as the gas component, have been carried out to explain observations covering a wide spectral range encompassing near-infrared to ...

Theoretical studies of dusty plasmas have been performed by focusing attention principally on collective phenomena and on grain motion. This thesis consists of a collection of seven published papers that explore both the collective behavior of a complex plasma system as well as the dynamics of grains in plasmas. In paper 1, a mechanism that explains the energy gain which leads to the self excit...

BACKGROUND Dust events have long been recognized to be associated with a higher mortality risk. However, no study has investigated how prolonged dust events affect the spatial variability of mortality across districts in a downwind city. METHODS In this study, we applied a spatial regression approach to estimate the district-level mortality during two extreme dust events in Hong Kong. We comp...

Home exposures to aeroallergens are an important environmental factor in allergic sensitization and in the development and exacerbation of asthma. We assessed variations in home concentrations of dust mite, cockroach, cat, and dog allergens in dust collected in the main living areas of asthmatics' homes by family income, mother's education, dwelling type, population density, household populatio...

3D Continuum radiative transfer in complex dust configurations around young stellar objects and active nuclei II. 3D Structure of the dense molecular cloud core ρ Oph D Abstract. Constraints on the density and thermal 3D structure of the dense molecular cloud core ρ Oph D are derived from a detailed 3D radiative transfer modeling. Two ISOCAM images at 7 and 15 µm are fitted simultaneously by re...