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Markarian 273 and Markarian 231 are ultra-luminous IR galaxies which show signs of merger activity. Their radio continuum and spectral line emission has been imaged on scales of tens of parsec using MERLIN. Mrk 273 and Mrk 231 are classed as Seyfert types 2 and 1 respectively. The distribution and velocity gradients shown by OH masers and HI absorption are consistent with material in a rotating disk or ring, with the axis at greater than 45° to the line of sight in Mrk 273, and at less than 45° to the line of sight in Mrk 231. We estimate the amount of mass enclosed and infer its distribution from irregularities in the maser morphologies and comparison with HI and radio continuum data.
Depuis la dernière Assemblée générale, notre commission a eu le regret de perdre deux de ses membres les plus éminents: M. Paul Stroobant, directeur de l’Observatoire Royal de Belgique et M. W. H. Pickering, ancien directeur des succursales de l’Observatoire de Harvard à Arequipa (Pérou) et Mandeville (Jamaïque). Les recherches de M. Paul Stroobant se rapportent pour une grande partie aux planètes, notamment Mercure, Vénus, les petites planètes et Saturne dont il étudia pendant des années les anneaux. Il faisait partie de notre Union comme président de la 5e commission et membre de beaucoup d’autres.
Although it is widely believed that management of the airway is difficult in surgery for retrosternal goitre, a review of the literature, revealing management of 1969 patients with retrosternal goitre, provided scant evidence of difficult intubation or post-operative tracheomalacia resulting in tracheal collapse. This was reflected in our own series of 18 thyroidectomies for retrosternal goitre performed at our hospitals.
One of the current goals of Martian exploration is to find evidence for extinct (or even extant) life. Carbon (an essential ingredient of life on Earth) is known to occur on Mars as CO2 in the atmosphere and frozen in the polar caps; it is inferred to be present as carbonates in the Martian crust and soils. We are attempting to define and quantify the different carbon reservoirs on Mars, so that we can follow Mars' carbon cycle. This paper discusses a primordial magmatic component that could be the starting point of such a cycle. The nature, distribution and isotopic composition of carbon was measured in a suite of Martian meteorites, comprising Chassigny and 11 shergottites. Other Martian meteorites were not included, as they sample rocks that have been altered by fluids at Mars' surface. Our results, obtained by high-resolution stepped combustion and mass spectrometry, show that the magmatic component has a very variable abundance of 1–100 ppm, with δ13C~−20±4‰. This value is close to magmatic carbon determined for Moon and for Vesta (the parent body of the HED basaltic meteorites), but very different from that of Earth.