SciCombinator

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Concept: Alexander von Humboldt

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…︁ We should not only honor the history of chemistry by commemorating anniversaries, but also acknowledge it as one of our disciplines. According to Wilhelm von Humboldt, it is only knowledge of the history of chemistry that gives us the best prerequisites for shaping the future of chemistry-from a stronger interdisciplinary and an international perspective …︁ Read more in the Editorial by Thomas Geelhaar.

Concepts: Alexander von Humboldt, Wilhelm von Humboldt

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José Celestino Mutis y Bosio was a Spanish physician, naturalist, astronomer, priest, theologian and mathematician, and one of the icons of the Enlightment Age both in Spain and the American Continent. As the Viceroy’s personal doctor, he travelled to the territory of New Granada in what is now Colombia. Mutis was the creator and first leader of the Royal Botanic Expedition of New Granada to study South American wildlife, discovering thousands of new species. He also launched several Public Health measures in the Santa Fe area, helping to introduce a vaccination campaign. Mutis was the first person to introduce Newtonian physics in the Spanish America and he established the first Observatory in the New World which is still in use. He was deeply admired and recognized as a prominent scientist by great personalities of his time including Carl von Linée and Alexander von Humboldt.

Concepts: Spain, South America, Americas, Latin America, Christopher Columbus, Indigenous peoples of the Americas, Mexico City, Alexander von Humboldt

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Over 200 years ago Alexander von Humboldt (1808) observed that plant and animal diversity peaks at tropical latitudes and decreases toward the poles, a trend he attributed to more favorable temperatures in the tropics. Studies to date suggest that this temperature-diversity gradient is weak or nonexistent for Bacteria and Archaea. To test the impacts of temperature as well as pH on bacterial and archaeal diversity, we performed pyrotag sequencing of 16S rRNA genes retrieved from 165 soil, sediment and biomat samples of 36 geothermal areas in Canada and New Zealand, covering a temperature range of 7.5-99 °C and a pH range of 1.8-9.0. This represents the widest ranges of temperature and pH yet examined in a single microbial diversity study. Species richness and diversity indices were strongly correlated to temperature, with R(2) values up to 0.62 for neutral-alkaline springs. The distributions were unimodal, with peak diversity at 24 °C and decreasing diversity at higher and lower temperature extremes. There was also a significant pH effect on diversity; however, in contrast to previous studies of soil microbial diversity, pH explained less of the variability (13-20%) than temperature in the geothermal samples. No correlation was observed between diversity values and latitude from the equator, and we therefore infer a direct temperature effect in our data set. These results demonstrate that temperature exerts a strong control on microbial diversity when considered over most of the temperature range within which life is possible.The ISME Journal advance online publication, 16 January 2014; doi:10.1038/ismej.2013.237.

Concepts: Archaea, Bacteria, Ribosomal RNA, Tropics, Tropic of Cancer, 16S ribosomal RNA, Equator, Alexander von Humboldt

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Alfred Russel Wallace (1823-1913) is an important figure in the history of science, but there remain many questions about the nature of his world view, and how it developed. Here, Wallace’s appreciation of the role of final causes in evolution is linked to some of its probable origins, with an emphasis on the influence of Alexander von Humboldt (1769-1859). The question is then asked whether a final causes-based scientific agenda might be possible, and answered by drawing attention to two current efforts in that direction by Adrian Bejan, and by the author. A sketch of the latter approach, adapted from Spinozian thinking, is given, with an empirical example involving drainage basin morphology that suggests structural influences of a final causes sort.

Concepts: Scientific method, Natural selection, Science, Question, Charles Darwin, History of biology, Alfred Russel Wallace, Alexander von Humboldt

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After extensive experimentation during the 1790s, Alexander von Humboldt remained skeptical about “animal electricity” (and metallic electricity), writing instead about an ill-defined galvanic force. With his worldview and wishing to learn more, he studied electric eels in South America just as the new century began, again using his body as a scientific instrument in many of his experiments. As had been the case in the past and for many of the same reasons, some of his findings with the electric eel (and soon after, Italian torpedoes) seemed to argue against biological electricity. But he no longer used galvanic terminology when describing his electric fish experiments. The fact that he now wrote about animal electricity rather than a different “galvanic” force owed much to Alessandro Volta, who had come forth with his “pile” (battery) for multipling the physical and perceptable effects of otherwise weak electricity in 1800, while Humboldt was deep in South America. Humboldt probably read about and saw voltaic batteries in the United States in 1804, but the time he spent with Volta in 1805 was probably more significant in his conversion from a galvanic to an electrical framework for understanding nerve and muscle physiology. Although he did not continue his animal electricity research program after this time, Humboldt retained his worldview of a unified nature and continued to believe in intrinsic animal electricity. He also served as a patron to some of the most important figures in the new field of electrophysiology (e.g., Hermann Helmholtz and Emil du Bois-Reymond), helping to take the research that he had participated in to the next level.

Concepts: Electricity, Fish, Eel, Electric eel, Alexander von Humboldt, Luigi Galvani, Alessandro Volta, Voltaic pile

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To evaluate changes in prevalence of impaired motor coordination among 6-year-olds of a geographically defined area in Germany between the years 1990 and 2007.

Concepts: Motor control, Motor coordination, Germany, Adolf Hitler, Reichstag Fire Decree, Paul von Hindenburg, 1964, Alexander von Humboldt