An optical and near-infrared study of the AM Herculis-type binary CW 1103+254

Original article can be found via: http://cdsads.u-strasbg.fr/ Copyright Royal Astronomical Society [Full text of this article is not available in the UHRA]All main components of the AM Herculis-type binary CW 1103 + 254 can be distinguished by means of observations encompassing optical and near-IR photometry and polarimetry, together with optical spectroscopy and spectropolarimetry. The M-dwarf secondary's IR magnitude is used to estimate the distance of the system as 136 pc. Observed emission line profiles can be understood in terms of two components, one of which originates in the white dwarf's infalling stream of material while the other comes from the vicinity of the secondary. The excess radiation noted during the bright phase can be understood as cyclotron radiation from the shock-heated region near the white dwarf magnetic pole. Changes that occurred in the system in 1982 and 1983 indicate precessional motion of either the white dwarf rotation or the magnetic axis.Peer reviewe

DEFICIÊNCIAS MINERAIS NO CULTIVAR DE ALGODÃO IAC-22

Desenvolveu-se um experimento em solução nutritiva, omitindo-se os nutrientes, um a um, com o objetivo de descrever as deficiências minerais no cultivar de algodão (Gossypium hirsutum L.) IAC 22. As deficiências de N, P, K, Ca, Mg e B causaram reduções significativas na produção de matéria seca da parte aérea das plantas, enquanto a produção de matéria seca das raízes foi diminuída na deficiência de N, K, Ca, Mg e B, assim como quando houve excesso de Mn. Plantas deficientes em Fe e Mo mostraram maior desenvolvimento vegetativo que aquelas do tratamento completo, mas o número de estruturas reprodutivas foi menor.<br>An experiment was set up in nutrient solutions, in order to describe the nutrient deficiency symptoms of cotton plants (Gossypium hirsutum L.) cultivar IAC 22. Plants were grown either in complete solution or solutions lacking one nutrient. The absence of N, P, K, Ca, Mg and B in the nutrient solution led to significant decreases in shoot dry matter. Root dry matter decreased in solutions lacking N, K, Ca, Mg and B, as well as in excess of Mn. Plants deficient for Fe and for Mo had less flowers and buds but an increased vegetative growth