801 research outputs found
Variability of sea ice cover in northern Fram Strait during the past 30 ka: A biomarker approach
PubMan - one Repository with multiple Usage und Re-Use Possibilities
PubMan is an application which allows members of research organizations to store, manage and enrich their publications. The app is based on the eSciDoc infrastructure, a joint project run by the Max Planck Digital Library (MPDL) and the Fachinformationszentrum (FIZ) Karlsruhe.
Presenting scholarly work in the World Wide Web has become an important and common procedure for research communities seeking to enhance the visibility of their research results as well as to initiate scientific collaboration and information exchange. In response to that trend much emphasis has been put on the possibility of providing multiple re-use options for metadata, full texts and supplementary material during the conception and development of PubMan. Our repository software facilitates the integration of user-defined publication lists in local websites as well as in personal and topic-centered WordPress blogs. The paper will depict these two reuse possibilities with examples of operational usage scenarios after giving an overview of the basic concepts and functionalities of PubMan
Andean-Pacific Commerce and Credit: Bolivian Traders, Asian Migrant Businesses, and International Manufacturers in the Regional Economy
[eng]This article deals with the changing configuration of regional trade in consumer electronics. Based on data from ethnographic fieldwork since 2013 at various locations (marketplaces in La Paz, Bolivia, and the free trade zone of Iquique, Northern Chile), and a historical analysis of the last three decades, the aim of the article is to understand Bolivian popular commerce as it becomes increasingly connected to East Asian commodity chains and corporations, specifically China-centered international markets. At the free zone, the process is characterized by supplier's credit circulating between Asian migrant merchants and Bolivian traders. At urban marketplaces in Bolivia, locally specific forms of trust-building are adopted by all actors, including multinational corporations, although the latter refrain from informal credit. Recent Chinese-Bolivian joint ventures and Chinese corporate investments in Bolivia incorporate past practices but also try to streamline commodity chains. The analysis shows that the engagement of multinational enterprises contributes to growing socio-economic differences among Bolivian traders.[spa]Este artículo analiza la configuración cambiante del comercio regional de artefactos electrónicos. Basado en un trabajo etnográfico iniciado en 2013 en varias localidades (mercados populares en La Paz, Bolivia, y la zona franca de Iquique, norte de Chile) y en un análisis histórico de las últimas tres déadas, el objetivo ha sido comprender la conexión cada vez mayor del comercio popular boliviano con las cadenas comerciales y empresas del este asiático, específicamente de los mercados internacionales centrados en China. De este modo, se puede afirmar que en la zona franca, el proceso se caracteriza por la circulación del crédito comercial entre los distribuidores de origen asiático y los comerciantes bolivianos. Mientras que en mercados urbanos en Bolivia, las formas locales de generar confianza han sido adoptadas por todos los actores, también por las empresas transnacionales. Otro aspecto a destacar es cómo las recientes cooperaciones chino–bolivianas e inversiones chinas en Bolivia también incorporan prácticas pasadas, pero al mismo tiempo intentan fomentar cadenas comerciales racionalizadas; y como consecuencia de estos procesos, las empresas multinacionales están contribuyendo a la creciente diferenciación socio-económica entre los comerciantes boliviano
PubMan - one Repository with multiple Usage und Re-Use Possibilities
PubMan is an application which allows members of research organizations to store, manage and enrich their publications. The app is based on the eSciDoc infrastructure, a joint project run by the Max Planck Digital Library (MPDL) and the Fachinformationszentrum (FIZ) Karlsruhe.
Presenting scholarly work in the World Wide Web has become an important and common procedure for research communities seeking to enhance the visibility of their research results as well as to initiate scientific collaboration and information exchange. In response to that trend much emphasis has been put on the possibility of providing multiple re-use options for metadata, full texts and supplementary material during the conception and development of PubMan. Our repository software facilitates the integration of user-defined publication lists in local websites as well as in personal and topic-centered WordPress blogs. The paper will depict these two reuse possibilities with examples of operational usage scenarios after giving an overview of the basic concepts and functionalities of PubMan
Neoglacial cooling culminates in rapid sea ice oscillations in eastern Fram Strait
EGU2011-407
The spatial and temporal distribution of sea ice in the subpolar North Atlantic is mainly controlled by the advection of warm Atlantic Water via the Norwegian and West Spitsbergen Current in eastern Fram Strait. Simultaneously, polar water and sea ice from the Arctic Ocean is transported southward by the East Greenland Current. Hence, variations in the strength of this oceanic circulation regime may either stimulate or reduce the sea ice extent.
Based on organic geochemical studies of a high-resolution sediment core from eastern Fram Strait we provide new evidence for the highly variable character of the sea ice conditions in this area. The combination of the sea ice proxy IP25 (Belt et al., 2007) with phytoplankton derived biomarkers (e.g. brassicasterol, dinosterol; Volkman 2006) enables a reliable reconstruction of sea surface and sea ice conditions, respectively (Müller et al., 2009; 2010). By means of these biomarkers, we trace gradually increasing sea ice occurrences from the Mid to the Late Holocene – consistent with the neoglacial cooling trend. Throughout the past ca. 3,000 years (BP) we observe a significant short-term variability in the biomarker records, which points to rapid advances and retreats of the sea ice cover at the continental margin of West Spitsbergen. The co-occurrence of IP25 and phytoplankton markers, however, suggests that the primary productivity benefits from these sea ice surges. As such, higher amounts of open-water phytoplankton biomarkers together with peak abundances of IP25 indicate recurring periods of enhanced ice-edge phytoplankton blooms at the core site. To what extent a seesawing of temperate Atlantic Water may account for these sea ice fluctuations requires further investigation. Concurrent variations in Siberian river discharge (Stein et al., 2004) or Norwegian glacier extents (Nesje et al., 2001), however, strengthen that these fluctuations may be assigned to variations in the North Atlantic/Arctic Oscillation (NAO/AO) and (hence) a weakened/accelerated Atlantic Water input and Arctic sea ice export
Modern spatial sea-ice variability in the central Arctic Ocean and adjacent marginal seas: Reconstruction from biomarker data
Sea ice is a fundamental component of Earth’s climate system, contributing to heat reduction (albedo) and deep-water formation. In order to understand processes controlling the recent dramatic reduction in Arctic sea-ice cover, it is essential to determine spatial and temporal changes in sea-ice occurrence and its natural variability in the present and past. Here, we present biomarker data from surface sediments and related to the modern spatial (seasonal) sea-ice variability in the central Arctic Ocean and adjacent marginal seas (i.e., Bering, Chukchi, Laptev and Kara seas) as well as the Fram Strait/Yermak Plateau area. We determined concentrations of the sea-ice diatom-derived biomarker “IP25″ (highly-branched isoprenoid – HBI – with 25 carbon atom; Belt et al., 2007), phytoplankton-derived biomarkers (brassicasterol and dinosterol) and terrigenous biomarkers (campesterol and Î_-sitosterol) to estimate recent sea-ice conditions in the study area. A combined phytoplankton-IP25 biomarker approach (“PIP25 index”; Müller et al., 2009, 2011) is used to reconstruct the modern sea-ice distribution more quantitatively. In addition, the distribution pattern of HBI-diene/IP25 ratios has been determined to test a proposed relationship between the diene/IP25 ratio and sea-surface temperatures in Arctic marginal ice-zone environments (Fahl and Stein, 2012; Stein et al., 2012). Assessment of sea-ice conditions based on these biomarker data display that a quite stable marginal ice zone exists along the continental shelf/slope of Kara and Laptev seas during summer/early fall. Elevated IP25 as well as brassicasterol and dinosterol values occurring in the central Kara and Laptev seas are related to extended sea-ice-cover and higher primary production (close to ice-edge situation). Further to the north and the central Arctic Ocean, lower IP25 and phytoplankton biomarker concentrations point to a more close sea-ice cover situation
The Expedition PS128 of the Research Vessel POLARSTERN to the Weddell Sea, Lazarew Sea, Riiser-Larsen Sea, Cosmonaut Sea and Cooperation Sea in 2022
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