2,104 research outputs found
SEASONAL VARIABILITY OF CENTRAL ARCTIC OCEAN SEA-ICE COVER: NEW BIOMARKER (IP25 AND PIP25) DATA FROM SEDIMENT TRAPS DEPLOYED ON SOUTHERN LOMONOSOV RIDGE
During the Polarstern 1995 Expedition, a long-term mooring system with two cone-shaped multi-sampling traps was deployed at the dominantly ice-covered western slope of the southern Lomonosov Ridge (81°04.5'N, 138°54.0'E, 1712 m water depth). One trap was installed at 150 m below the sea surface, the other at 150 m above the bottom at 1550 m depth; material was collected in 20 time intervals between September 1995 and August 1996. For background data see Fahl and Nöthig (2007). Here, we present new biomarker data recording the seasonal variability of sea-ice cover. This type of data representing modern seasonal variability of the sea-ice biomarker proxies, was not available so far but may help significantly the interpretation of these proxies to be used in sedimentary records for reconstruction of paleo-sea-ice distributions.
In this study, we have focused on the novel sea ice proxy IP25, a direct proxy for sea ice coverage (Belt et al., 2007). Furthermore, we used the phytoplankton-IP25 index (PIP25 Index), a further development of the IP25 index, based on the coupling of the environmental information carried by IP25 (sea ice) and brassicasterol (open-water phytoplankton productivity) (Müller et al., 2011).
The interval November 1995 to June 1996 is characterized by the absence of the sea-ice proxy IP25 (except very minor values for January and April), suggesting a predominantly permanent sea ice cover at the trap location. During July/August 1996, maximum fluxes of the diatom-specific fatty acids and brassicasterol as well as maximum contents of biogenic opal (Fahl and Nöthig, 2007) indicate increased primary productivity. The marine organic matter (here POC, brassicasterol, and fatty acids) and the IP25 values decrease systematically from 150 to 1550m depth, indicating the typical biogeochemical degradation with increasing water depth. Due to the coincidence of maximum abundances of sea-ice proxies and open-ocean primary productivity proxies during the July/August time interval we propose a ice-edge situation characterized by increased phytoplankton productivity and sea-ice algae input. This interpretation is also supported by the phytoplankton-IP25 index (PIP25 Index), reaching quite high values of 0.5-0.8. It seems to be that in general PIP25 values do not change significantly between the shallow and deep trap, i.e., with increasing water depth, an important observation when thinking about the interpretation of PIP25 sedimentary records.
The distinctly reduced September/October values of brassicasterol and fatty acids suggest a decrease in primary productivity, probably related to the start of new-ice formation in late September. This situation is reflected in high IP25 values and high PIP25 ratios. Whereas for October no IP25 was determined in the shallow trap, medium-high IP25 values were determined in the deep trap with maximum PIP25 ratio of about 0.7. This may indicate lateral IP25 input, but also means that in this case the PIP25 ratios should be interpreted with caution
A CGE-Analysis of Energy Policies Considering Labor Market Imperfections and Technology Specifications
The paper establishes a CGE/MPSGE model for evaluating energy policy measures with emphasis on their employment impacts. It specifies a dual labor market with respect to qualification, two different mechanisms for skill specific unemployment, and a technology detailed description of electricity generation. Non clearing of the dual labor market is modeled via minimum wage constraints and via wage curves. The model is exemplarily applied for the analysis of capital subsidies on the application of technologies using renewable energy sources. Quantitative results highlight that subsidies on these technologies do not automatically lead to a significant reduction in emissions. Moreover, if emission reductions are achieved these might actually partly result from negative growth effects induced by the promotion of cost inefficient technologies. Inefficiencies in the energy system increase unemployment for both skilled and unskilled labor.CGE, Energy Economic Analysis, Employment Impact, Choice of Technology
Attitudes of Swedish Learners of Japanese towards Japanese Dialects: A Quantitative Study
The present thesis is a quantitative study investigating the attitudes of Swedish learners of Japanese towards Japanese dialects. Current or previous Swedish students of Japanese completed a survey in which they listened to recordings of five different dialects of Japanese, and evaluated these dialects in terms of various personality traits. Furthermore, their ability to identify the dialects was tested. The results of the study showed that Swedish learners of Japanese held quite neutral attitudes towards Japanese dialects, and were also generally similar to native Japanese attitudes. Differences in attitudes were found depending on the informants’ gender, self-perceived proficiency of Japanese and previous exposure to Japanese
Some Relationships Between Glaciers And Climate In Alaska
Thesis (Ph.D.) University of Alaska Fairbanks, 197
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
Proposta de uma linha de montagem de barcos de lazer de médio porte: uma aplicação dos conceitos de manufatura enxuta
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2010O atual cenário competitivo entre as empresas colabora para que o nível de exigência por parte dos consumidores aumente, em virtude da diversidade de produtos encontrados no mercado. Por essa razão, as empresas de manufatura, para permanecerem competitivas, procuram focar sua atenção na melhoria do processo produtivo, buscando eliminar os desperdícios, reduzir o tempo e o custo para a fabricação dos produtos, melhorar a qualidade da informação para, assim, obter produtos de elevada qualidade, satisfazendo o cliente. Neste contexto encontra-se a indústria náutica brasileira, que está em crescente expansão, principalmente no ramo de barcos para lazer e pesca, setor em que se encontra o maior o potencial náutico do Brasil, tendo em vista a sua grande e diversificada costa, imensas bacias hidrográficas e clima quente. Todavia, mesmo diante deste quadro, a fabricação de barcos para lazer no Brasil é ainda considerada artesanal, devido à baixa demanda destes produtos no mercado interno e externo, razão pela qual não há muito investimento na melhoria da qualidade do processo. Frente a isso, a presente dissertação, utilizando os conceitos de manufatura enxuta ("Lean Manufacturing"), derivados do Sistema Toyota de Produção, apresenta uma análise da linha de montagem de um barco de 30 pés em um estaleiro de médio porte, na região da grande Florianópolis, com o objetivo de mostrar a aplicabilidade dessa filosofia na melhoria do processo de fabricação de barcos. Para isso, realizou-se inicialmente uma pesquisa bibliográfica apresentando uma breve história da construção naval no Brasil. Na sequência, são mostradas as ferramentas para a aplicação do pensamento enxuto, que incluem o layout celular, fluxo de valor, nivelamento de operações e células de manufatura. Por fim, descreve-se a experiência proposta para o chão de fábrica propondo melhorias ao processo produtivo por meio de um gerenciamento visual de informações
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