998 resultados para Alexandre von Humboldt


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* This work has been supported by the Office of Naval Research Contract Nr. N0014-91-J1343, the Army Research Office Contract Nr. DAAD 19-02-1-0028, the National Science Foundation grants DMS-0221642 and DMS-0200665, the Deutsche Forschungsgemeinschaft grant SFB 401, the IHP Network “Breaking Complexity” funded by the European Commission and the Alexan- der von Humboldt Foundation.

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∗The author was partially supported by Alexander von Humboldt Foundation and the Contract MM-516 with the Bulgarian Ministry of Education, Science and Thechnology.

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* The second author is supported by the Alexander-von-Humboldt Foundation. He is on leave from: Institute of Mathematics, Academia Sinica, Beijing 100080, People’s Republic of China.

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2010 Mathematics Subject Classification: Primary 65D30, 32A35, Secondary 41A55.

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Approaches to quantify the organic carbon accumulation on a global scale generally do not consider the small-scale variability of sedimentary and oceanographic boundary conditions along continental margins. In this study, we present a new approach to regionalize the total organic carbon (TOC) content in surface sediments (<5 cm sediment depth). It is based on a compilation of more than 5500 single measurements from various sources. Global TOC distribution was determined by the application of a combined qualitative and quantitative-geostatistical method. Overall, 33 benthic TOC-based provinces were defined and used to process the global distribution pattern of the TOC content in surface sediments in a 1°x1° grid resolution. Regional dependencies of data points within each single province are expressed by modeled semi-variograms. Measured and estimated TOC values show good correlation, emphasizing the reasonable applicability of the method. The accumulation of organic carbon in marine surface sediments is a key parameter in the control of mineralization processes and the material exchange between the sediment and the ocean water. Our approach will help to improve global budgets of nutrient and carbon cycles.

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The Baltic Sea is the largest brackish water area of the world. On the basis of the data from 16 cruises, we show the seasonal and vertical distribution patterns of the appendicularians Fritillaria borealis, Oikopleura dioica and the cyclopoid copepod Oithona similis, in the highly stratified Bornholm Basin. These species live at least temporarily below the permanent halocline and use different life strategies to cope with the brackish environment. The cold-water species F. borealis is abundant in the upper layers of the water column before the thermocline develops. With the formation of the thermocline abundance decreases and the specimens outlast higher temperatures below the halocline. Distribution and strategy suggest that F. borealis might be a glacial relict species in the Baltic Sea. Although Oikopleura dioica is only abundant during summer, O. similis is present all year round. Both species have in common that their vertical distribution is restricted to the waters below the halocline, most likely due to their requirements of higher salinities. We argue that the observed strategies are determined by ecophysiological constraints and life history traits. These species share an omnivorous feeding behaviour and the capability to utilise a spectra of small particles as food. As phytoplankton concentration is negligible below the halocline, we suggest that these species feed on organic material and heterotrophic organisms that accumulate in the density gradient of the halocline. Therefore, the deep haline waters in the Baltic Sea represent a habitat providing shelter from predation and food supply for adapted species that allows them to gather sufficient resources and to maintain populations.

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A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data points from the global oceans and coastal seas, spanning four decades (1968-2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO2 data collection and the importance of quantifying net global oceanic CO2 uptake and its changes, sustained data synthesis and data access are priorities.

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La tesis doctoral presentada da cuenta de las "figuraciones de la esclavitud" en un amplio corpus textual (ensayos y novelas) de autores representativos de la "narrativa antiesclavista" en el siglo XIX, centrada en las áreas de Cuba y Brasil. Desde una perspectiva comparativa, que atiende a los planos retóricos y discursivos, se analizan puntualmente novelas y ensayos de autores canónicos como Gertrudis Gómez de Avellaneda, Cirilo Villaverde, José Antonio Saco, Alejandro von Humboldt, José de Alencar, Bernardo Guimaraes, Joaquim Nabuco y Jean-Baptiste Debret. A la vez, se incorpora la plasmación de un enfoque interdisciplinar en el análisis de la "narrativa antiesclavista", abordando también aspectos que remiten a la historiografía política, social y económica sobre el proceso de la esclavitud en el período de 1840-1880, junto con otros de articulación antropológica, cultural y estética en ambas zonas mencionadas

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La tesis doctoral presentada da cuenta de las "figuraciones de la esclavitud" en un amplio corpus textual (ensayos y novelas) de autores representativos de la "narrativa antiesclavista" en el siglo XIX, centrada en las áreas de Cuba y Brasil. Desde una perspectiva comparativa, que atiende a los planos retóricos y discursivos, se analizan puntualmente novelas y ensayos de autores canónicos como Gertrudis Gómez de Avellaneda, Cirilo Villaverde, José Antonio Saco, Alejandro von Humboldt, José de Alencar, Bernardo Guimaraes, Joaquim Nabuco y Jean-Baptiste Debret. A la vez, se incorpora la plasmación de un enfoque interdisciplinar en el análisis de la "narrativa antiesclavista", abordando también aspectos que remiten a la historiografía política, social y económica sobre el proceso de la esclavitud en el período de 1840-1880, junto con otros de articulación antropológica, cultural y estética en ambas zonas mencionadas

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La tesis doctoral presentada da cuenta de las "figuraciones de la esclavitud" en un amplio corpus textual (ensayos y novelas) de autores representativos de la "narrativa antiesclavista" en el siglo XIX, centrada en las áreas de Cuba y Brasil. Desde una perspectiva comparativa, que atiende a los planos retóricos y discursivos, se analizan puntualmente novelas y ensayos de autores canónicos como Gertrudis Gómez de Avellaneda, Cirilo Villaverde, José Antonio Saco, Alejandro von Humboldt, José de Alencar, Bernardo Guimaraes, Joaquim Nabuco y Jean-Baptiste Debret. A la vez, se incorpora la plasmación de un enfoque interdisciplinar en el análisis de la "narrativa antiesclavista", abordando también aspectos que remiten a la historiografía política, social y económica sobre el proceso de la esclavitud en el período de 1840-1880, junto con otros de articulación antropológica, cultural y estética en ambas zonas mencionadas

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Este artículo se propone analizar la escena del cresmólogo intruso en Aves, revalorizando la comedia aristofánica como fuente de conocimiento histórico. Este análisis se centra en la práctica oracular como una técnica de producción escrita vinculada a la autoridad religiosa. De esta manera, se exploran dos campos de estudios, como la comedia antigua y la adivinación griega, cuyo vínculo no ha sido explorado en profundidad. Para dar cuenta del momento crítico de la institución oracular durante la Guerra del Peloponeso, se reconstruyen perspectivas sobre dicho fenómeno en otras fuentes como Tucídides o Demóstenes. Esto no solo ofrece una mirada «cómica» sobre la adivinación, sino que también permite comprender la práctica oracular como técnica y, en consecuencia, qué elementos de su funcionamiento podían ser manipulados.

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In May of 1864, Maximilian of Austria reached the Mexican coast, being this journey his last, ending three years later with his execution. Much has been written about the reasons that prompted his acceptance of the crown of Mexico, a country so distant in every sense of his cultural environment. However, years ago Maximilian had traveled to Spain and Brazil (to Spain twice) and these experiences, although not determinant, greatly influenced the decision of the Archduke, who saw the chance to realize a dream he had conceived on his trip to Spain and that was consolidated during his stay in Brazil, as we can extract from his travel memoirs.

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Colombia se ha comprometido a nivel internacional a realizar acciones que conduzcan al país hacia el desarrollo sostenible, específicamente a proteger los recursos naturales. En línea con esta apuesta, la presente investigación propone la construcción de la Reserva Natural El Chuval, en el municipio El Retén, Magdalena. Para la construcción de dicha Reserva se realiza un diagnóstico que indica las principales características del Chuval, se identifican posibles riesgos para la conservación de sus valores ambientales, y se complementa el análisis con una propuesta de manejo que se enmarca en la metodología de Agendas Ambientales Locales desarrollada por la ONU. Pese a que el municipio es consciente de la relevancia ambiental del Chuval, aún no se han tomado decisiones definitivas para proteger esta zona, razón por la cual, la presente investigación busca llenar un vacío en el ordenamiento territorial del municipio, que fortalezca la protección de la Ciénaga Grande de Santa Marta.