995 resultados para 1873-1953


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An original karyotype (2n=34) of 3 shrews from two localities on Crete is described. It confirms the specific status of Crocidura zimmermanni Wettstein, 1953.

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In the mid-20th century, the southern parts of the Madres and Mont Coronat massif (Eastern Pyrenees, France) were characterized by a Mediterranean landscape shaped by human activity. Long-term use of these mountains for crops, livestock, and forestry led to an increase in grassland areas at the expense of forest. However, socioeconomic transformation (abandonment of agriculture and a decrease in the rural population) in recent decades has caused profound changes in this massif. Interpretation of aerial photographs (1953, 1969, 1988, and 2000) made it possible to detect and analyze the changes produced in the study area (6787 ha) during this period. In 1953 most of the massif landscape consisted of grasslands (38%) and open forests (18%), with some areas of dense forest (15%). By 2000, dense forest cover had doubled in size (31%), and grassland had decreased considerably (by 73% of the initial area). Since 1953, the study area has become more homogeneous, with a few local exceptions. The results of this study suggest that socioeconomic factors might be the main cause of landscape transformations in this period of approximately 50 years.

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This first of two papers allusive to the 200th birthday of Justus von Liebig (1803-1873) deals with the origins, life, education, ideas and influence of one of the great 19th century chemists. The principal characteristics of his "Giessen model of teaching research in chemistry" are presented, as well as the role played by many of his students in the evolution of chemical research in various countries. Liebig's strong personality, his controversies, his contribution to the chemical scene in Giessen and Munich are presented. Although few, the connections with Latin-American chemistry are focused.