The concept of t-(v, k) trades of block designs previously has been studied in detail. See for example A. S. Hedayat (1990) and Billington (2003). Also Latin trades have been studied in detail under various names, see A. D. Keedwell (2004) for a survey. Recently Khanban, Mahdian and Mahmoodian have extended the concept of Latin trades and introduced t-(v, k) Latin trades. Here we study the spec...

Trata-se da tradução de um dos mais importantes textos escritos pelo anarquista-geógrafo francês Jacques Élisée Reclus sobre ensino geografia, no qual apresenta uma visão bastante questionadora esta disciplina escolar. O texto foi escrito em 1903 e publicado neste mesmo ano Boletim Sociedade Belga Astronomia. RECLUS, Élisée. L'Enseignement la Géographie. Bulletin Société Belge d'Astronomie, n° ...

Most of the information on the gastrointestinal microflora of antarctic birds was obtained during the great decade of South-Polar exploration following the turn of the century. The report of Levin (1899) that bacteria could not be found in the intestines of arctic birds at Spitzbergen prompted similar studies by the naturalists and ship's physicians on the Antarctic expeditions. Ekel6f (1908) o...