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匹配条件: “Leitner” ,找到相关结果约233条。
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About Twistor Spinors with Zero in Lorentzian Geometry
Felipe Leitner
Symmetry, Integrability and Geometry : Methods and Applications , 2009,
Abstract: We describe the local conformal geometry of a Lorentzian spin manifold (M,g) admitting a twistor spinor φ with zero. Moreover, we describe the shape of the zero set of φ. If φ has isolated zeros then the metric g is locally conformally equivalent to a static monopole. In the other case the zero set consists of null geodesic(s) and g is locally conformally equivalent to a Brinkmann metric. Our arguments utilise tractor calculus in an essential way. The Dirac current of φ, which is a conformal Killing vector field, plays an important role for our discussion as well.
über die Quellen der mexikanischen Tafeln der Ansichten der Kordilleren“ im Nachlass Alexander von Humboldts
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2010,
Abstract: Article in German. Abstracts in German and Spanish.
Humboldt's works on Mexico
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2000,
Abstract: Article in English, Abstracts in Spanish and English. Humboldt wrote about Mexico from the perspective of a scientific explorer and naturalist. His works include his diaries, the Essai politique sur le royaume de la Nouvelle-Espagne, the Tablas géograficas, the Vues des Cordillères and a geographic atlas. Concerning the scientific aspect, the lack of a section on Mexico in the Relation historique is not a real deficit, since this can be found in the Essai. But only the diaries and letters from the journey, both published by the Alexander-von-Humboldt Research Centre, Berlin, can be considered an adequate substitute.The following will show the origin of Humboldt's writings on Mexico, offer historical and bibliographical facts and present the publications "Beitr ge zur Alexander von Humboldt-Forschung", as well as Humboldt’s handwritten estate as far as they are available to us.
Aus dem Humboldt-Nachla : Juan José de Oteyzas Beschreibung der Pyramiden von Teotihuacán
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2006,
Abstract: Article in German, Abstracts in English, German and Spanish.The papers of Alexander von Humboldt in Cracow (Poland) contain materials related to Mexico and Cuba, which Humboldt had collected. Among them is a manuscript describing Teotihuacan by Juan José de Oteyza, whom Humboldt had met during his stay at the “Real Seminario de Minería” in Mexico City. Humboldt himself never visited this pyramid precinct. In cases like these he used his extensive information network to complete his own observations in his travel journals. This can be seen in the following comparison of Oteyza’s manuscript with Humboldt’s text which was published later.
Unbekannte Venezuela-Karten Alexander von Humboldts
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2001,
Abstract: Article in German, Abstracts in English and German.During his American journey Humboldt was mainly interested in geosciences, as the later published geographical folio atlasses and an enormous number of drawings in his diaries indicate. The following gives three almost unknown examples of how Humboldt enriched the geographical and geological knowledge about Venezuela:1. a profile map of Venezuela’s coast. Only in 1853 Humboldt sent this result of the American journey to the editor Julius Ewald who published it in his important geological journal.2. Humboldt’s manuscript map of the Orinoco, which has not been published until today;3. a geographical map (published in 1812) of the river Casiquiare, which connects the Orinoco and the Rio Negro. Humboldt studied the Casiquiare during his Orinoco boat trip to show this connection (this was of high economic interest at the time) and, furthermore, the bifurcation of the Orinoco (one of the most important geographical results of Humboldt’s American journey).
Humboldt, Cotta, Ritter. Eine Miszelle über die Arbeit an einer Edition
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2008,
Abstract: Article in German, Abstracts in English, German and SpanishThrough the work on editing projects sometimes historical and biographical details are discovered. In this paper a letter from A. v. Humboldt to his publisher J. G. v. Cotta serves as an example of how the correct date of a wrongly dated letter could be found. The necessary research to answer this question also brought to light some new facts as to a meeting between Humboldt and geographer C. Ritter in Paris in 1824. We also learn about some topics on which Humboldt was working at the time and about his relationship to the French Court.
"Anciennes folies neptuniennes!" über das wiedergefundene "Journal du Mexique à Veracruz" aus den mexikanischen Reisetagebüchern A. v. Humboldts
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2002,
Abstract: Article in German, Abstracts in English and German.When Humboldt in 1853 reread his 1804 notebook of his travel from Mexico City to Veracruz, he criticized his “old Neptunistic follies” in a marginal note. Scholars have doubted that he was still a Neptunist in 1804, but this text and Humboldt’s later remark prove it.Curiously, these few pages were omitted from his South American notebooks when they were rebound in 9 volumes at the end of his life. Together with the Berlin State Library autograph collection, these missing pages were relocated during World War II, and for decades they were considered lost. Actually, they are well preserved in the Krakau University Library, where I found them recently. They form a valuable addition to Margot Faak’s edition of Humboldt’s Latin American diaries.This paper discusses the manuscript, showing the development of Humboldt’s opinions in some disciplines he was concerned with. Some of these developments represent paradigmatic changes in natural history, especially in geology.
Vielschichtigkeit und Komplexit t im Reisewerk Alexander von Humboldts - Bibliographischer Hintergrund
Ulrike Leitner
HiN. Alexander von Humboldt im Netz , 2005,
Abstract: Article in German, Abstracts in English, German and Spanish.The network structure of Humboldt’s American travel journals with emphasise on the bibliographic background is investigated on the basis of O. Ette’s concept of Humboldtian writing. The complexity of Humboldt’s writing is shown in the following dimensions: splitting up into disciplines, hypertext structure of singular texts, multilinguality, connections to Humboldt’s oeuvre and correspondence, Humboldt’s network in the scientific community. This specific structure cannot be fully understood in a strictly linear reading (which is what a regular book asks for), especially because of the lack of a new indexed edition of his travelogues. Therefore, a digital library could be an adequate medium to represent Humboldt’s scientific writing and, consequently, for his specific organisation of knowledge.
The Journal of A. v. Humboldt in Spain
Leitner, Ulrike
Asclepio : Revista de Historia de la Medicina y de la Ciencia , 2011,
Abstract: The Spanish diary can surprisingly not be found in his bounded diaries from his American travels, but in a separate folder of his legacy in Berlin, where Humboldt collected material which he wanted to use for his publication about Spain. So it remained undiscovered until recently. Humboldt’s notes contain geognostic descriptions as well as his observations about climate, vegetation, electricity of the atmosphere, etc. The comparison with Humboldt’s publication of 1825 facilitates to gain insight into his scientific methods. El diario espa ol de Humboldt se encuentra sorprendentemente en una carpeta de su legado en Berlín, donde el mismo recopiló los materiales para su publicación sobre la meseta espa ola en la revista Hertha, y no en sus diarios encuadernados del viaje americano. Esto explica que no se hubieran descubierto hasta hace poco tiempo. El manuscrito contiene descripciones geognósticas, observaciones sobre el clima, la vegetación, la electricidad de la atmósfera, etc. La comparación con lo publicado de Humboldt en 1825 sobre la meseta espa ola que realizamos en las notas de esta edición facilitará al lector una aproximación a los métodos cientificos típicos de Humboldt.
Klinische Studien/Klinische Praxis: Liraglutid (Victoza(R)): GLP-1-Agonisten neu bewertet
Leitner H
Journal für Klinische Endokrinologie und Stoffwechsel , 2012,
Abstract:
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