924 resultados para Input and outputs


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Numerous studies use major element concentrations measured on continental margin sediments to reconstruct terrestrial climate variations. The choice and interpretation of climate proxies however differ from site to site. Here we map the concentrations of major elements (Ca, Fe, Al, Si, Ti, K) in Atlantic surface sediments (36 degrees N-49 degrees S) to assess the factors influencing the geochemistry of Atlantic hemipelagic sediments and the potential of elemental ratios to reconstruct different terrestrial climate regimes. High concentrations of terrigenous elements and low Ca concentrations along the African and South American margins reflect the dominance of terrigenous input in these regions. Single element concentrations and elemental ratios including Ca (e. g., Fe/Ca) are too sensitive to dilution effects (enhanced biological productivity, carbonate dissolution) to allow reliable reconstructions of terrestrial climate. Other elemental ratios reflect the composition of terrigenous material and mirror the climatic conditions within the continental catchment areas. The Atlantic distribution of Ti/Al supports its use as a proxy for eolian versus fluvial input in regions of dust deposition that are not affected by the input of mafic rock material. The spatial distributions of Al/Si and Fe/K reflect the relative input of intensively weathered material from humid regions versus slightly weathered particles from drier areas. High biogenic opal input however influences the Al/Si ratio. Fe/K is sensitive to the input of mafic material and the topography of Andean river drainage basins. Both ratios are suitable to reconstruct African and South American climatic zones characterized by different intensities of chemical weathering in well-understood environmental settings.

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This paper shows how one can infer the nature of local returns to scale at the input- or output-oriented efficient projection of a technically inefficient input-output bundle, when the input- and output-oriented measures of efficiency differ.

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This study subdivides the Potter Cove, King George Island, Antarctica, into seafloor regions using multivariate statistical methods. These regions are categories used for comparing, contrasting and quantifying biogeochemical processes and biodiversity between ocean regions geographically but also regions under development within the scope of global change. The division obtained is characterized by the dominating components and interpreted in terms of ruling environmental conditions. The analysis includes in total 42 different environmental variables, interpolated based on samples taken during Australian summer seasons 2010/2011 and 2011/2012. The statistical errors of several interpolation methods (e.g. IDW, Indicator, Ordinary and Co-Kriging) with changing settings have been compared and the most reasonable method has been applied. The multivariate mathematical procedures used are regionalized classification via k means cluster analysis, canonical-correlation analysis and multidimensional scaling. Canonical-correlation analysis identifies the influencing factors in the different parts of the cove. Several methods for the identification of the optimum number of clusters have been tested and 4, 7, 10 as well as 12 were identified as reasonable numbers for clustering the Potter Cove. Especially the results of 10 and 12 clusters identify marine-influenced regions which can be clearly separated from those determined by the geological catchment area and the ones dominated by river discharge.

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There has been a marked decline in the summer extent of Arctic sea ice over the past few decades. Data from autonomous ice mass-balance buoys can enhance our understanding of this decline. These buoys monitor changes in snow deposition and ablation, ice growth, and ice surface and bottom melt. Results from the summer of 2008 showed considerable large-scale spatial variability in the amount of surface and bottom melt. Small amounts of melting were observed north of Greenland, while melting in the southern Beaufort Sea was quite large. Comparison of net solar heat input to the ice and heat required for surface ablation showed only modest correlation. However, there was a strong correlation between solar heat input to the ocean and bottom melting. As the ice concentration in the Beaufort Sea region decreased, there was an increase in solar heat to the ocean and an increase in bottom melting.

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A driving argument behind recent EU treaty reforms was that more qualified majority voting (QMV) was required to reduce the potential dangers of legislative paralysis caused by enlargement. Whilst existing literature on enlargement mostly focuses on the question of what changed in the legislative process after the 2004 enlargement, the question of why these changes occurred has been given far less attention. Through the use of a single veto player theoretical model, this paper seeks to test and explain whether enlargement reduces the efficiency of the legislative process and alters the type of legislation produced, and whether QMV can compensate for these effects. In doing this, it offers a theoretical explanation as to why institutional changes that alter the level of cohesion between actors in the Council have an influence over both the legislative process and its outcomes.

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Acquisition by Processing Theory (APT) is a unified account of language processing and learning that encompasses both L1 and L2 acquisition. Bold in aim and broad in scope, the proposal offers parsimony and comprehensiveness, both highly desirable in a theory of language acquisition. However, the sweep of the proposal is accompanied by an economy of description that makes it difficult to evaluate the validity of key learning claims, or even how literally they are to be interpreted. Two in particular deserve comment; the first concerns the learning mechanisms responsible for adding new L2 grammatical information, and the second the theoretical and empirical status of the activation concept used in the model.

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It is widely observed that the global geography of innovation is rapidly evolving. This paper presents evidence concerning the contemporary evolution of the globe's most productive regions. The paper uncovers the underlying structure and co-evolution of knowledge-based resources, capabilities and outputs across these regions. The analysis identifies two key trends by which the economic evolution and growth patterns of these regions are differentiated-namely, knowledge-based growth and labour market growth. The knowledge-based growth factor represents the underlying commonality found between the growth of economic output, earnings and a range of knowledge-based resources. The labour market growth factor represents the capability of regions to draw on their human capital. Overall, spectacular knowledge-based growth of leading Chinese regions is evident, highlighting a continued shift of knowledge-based resources to Asia. It is concluded that regional growth in knowledge production investment and the capacity to draw on regional human capital reserves are neither necessarily traded-off nor complementary to each other. © 2012 Urban Studies Journal Limited.

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In this study, we present a new multiproxy data set of terrigenous input, marine productivity and sea surface temperature (SST) from 52 surface sediment samples collected along E-W transects in the Pacific sector of the Southern Ocean. Allochtonous terrigenous input was characterized by the distribution of plant wax n-alkanes and soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs). 230Th-normalized burial rates of both compound groups were highest close to the potential sources in Australia and New Zealand and are strongly related to lithogenic contents, indicating common sources and transport. Detection of both long-chain n-alkanes and brGDGTs at the most remote sites in the open ocean strongly suggests a primarily eolian transport mechanism to at least 110°W, i.e. by prevailing westerly winds. Two independent organic SST proxies were used, the UK'37 based on long-chain alkenones, and the TEX86 based on isoprenoid GDGTs. Both, UK'37 and TEX86 indices show robust relationships with temperature over a temperature range between 0.5 and 20°C, likely implying different seasonal and regional imprints on the temperature signal. While alkenone-based temperature estimates reliably reflect modern SST even at the low temperature end, large temperature residuals are observed for the polar ocean using the TEX86 index. 230Th-normalized burial rates of alkenones are highest close to the Subtropical Front and are positively related to lithogenic fluxes throughout the study area. In contrast, highest isoGDGT burial south of the Antarctic Polar Front is not related with dust flux but may be largely controlled by diatom blooms, and thus high opal fluxes during austral summer.

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Structural Health Monitoring (SHM) denotes a system with the ability to detect and interpret adverse changes in structures in order to improve reliability and reduce life-cycle costs. The greatest challenge for designing a SHM system is knowing what changes to look for and how to classify them. Different approaches for SHM have been proposed for damage identification, each one with advantages and drawbacks. This paper presents a methodology for improvement in vibration signal analysis using statistics information involving the probability density. Generally, the presence of noises in input and output signals results in false alarms, then, it is important that the methodology can minimize this problem. In this paper, the proposed approach is experimentally tested in a flexible plate using a piezoelectric (PZT) actuator to provide the disturbance.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)