863 resultados para Factor Analysis, Statistical


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In order to reconstruct past variations in the aeolian dust (Kosa) contribution to the Japan Sea, and to establish a direct link between terrestrial and marine climatic records, we have applied statistical procedures to distinguish and quantify detrital subcomponents within the detrital fraction of the late Quaternary hemipelagic sediments in the Japan Sea. Q-mode factor analysis with varimax and oblique rotation of the factors followed by multiple-regression analysis between mineral composition and factor loadings was conducted using six ''detrital'' elements. Four detrital subcomponents were defined, which are attributed to Kosa derived from ''typical'' loess, Kosa from ''weathered'' loess, and fine and coarse arc-derived detritus, respectively, based on comparisons with the chemical and mineral compositions of probable source materials. Using these detrital subcomponents, the variation in Kosa fraction was reconstructed for the last 200 ky. The results reveal millennial-scale as well as glacial-interglacial scale variations in Kosa contribution. Especially, millennial-scale variability of Kosa contribution suggests the presence of high frequency variation in summer monsoon precipitation in the central to east Asia during the last 200 ky.

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A statistical analysis ol 15 deep sea cores in the eastern North Atlantic off NW Africa revealed the typical fluctuation pattern of distinct species proups as has been described from various parts of the world ocean. Only the "WBF-group" appears to be correlated with global climatic changes, i.e. warmer periods as the Eemian and the Atlanticum. A partly antagonistic "High Productivity group" (HPR-group) is in general not linked with global changes but times of increased fertility in the surface water and the resulting flux of organic matter reaching the bottom. The groups were extracted from cluster analysis of more than 150 surface samples (HPR-group) and a factor analysis of selected cores (WBF-group). In contrast to previous studies the observed fluctuations can not be explained by drastic changes in bottom water masses, but by the pulsation of a distinct "High Productivity Patch" in space and time. At present, this patch is located below the well known upwelling area between 22° and 12° northern latitude. It shifted to the north (up to 27 °N) during the latest glacial period ( 18 ky), indicating an equivalent shift of upwelling productivity caused by advection of nutrient rich upwelling SACW-waters, probably during most of isotopic stages 2 and 3.

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In the northern McMurdo Sound (Ross Sea, Antarctica), the CRP-2/2A drillhole targeted the western margin of the Victoria Land Basin to investigate Neogene to Palaeogene climatic and tectonic history by obtaining continuous core and downhole logs. Well logging of CRP-2/2A has provided a complete and comprehensive dataset of in situ geophysical measurements. This paper describes the evaluation and interpretation of the downhole logging data using multivariate statistical methods. Two major types of multivariate statistical methods were each yielding a different perspective: (1) Factor analysis was used as an objective tool for classification of the drilled sequence based on physical and chemical properties. The factor logs are mirroring the basic geological controls (i.e., grain size, porosity, clay mineralogy) behind the measured geophysical properties, thereby making them easier to interpret geologically. (2) Cluster analysis of the logs groups similar downhole geophysical properties into one cluster, delineating individual logging or sedimentological units. These objectively and independently defined units, or statistical electrofacies, are helpful in differentiating lithological and sedimentological characterisations (e.g. grain size, provenance). The multivariate statistical methods of factor and cluster analysis proved to be powerful tools for fast, reliable, and objective characterisation of downhole geophysical properties at CRP-2/2A, resulting in interpretations which are consistent with sedimentological findings.

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Geological observations, using "free-diving" techniques (Figure I) were made in September, 1960 and March 1961 along two continuous profiles in the outer Kiel Harbor, Germany and at several other spot locations in the Western Baltic Sea. A distinct terrace, cut in Pleistocene glacial till, was found that was covered with varying amounts and types of recent deposits. Hand samples were taken of the sea-floor sediments and grainsize distribution determined for both the sediment as a whole and for its heavy mineral fraction. From the Laboratory and Field observations it was possible to recognize two distinct types of sand; Type I, Sand resulting from transportation over a long period of time and distance and Type 11, Sand resulting from little transportation and found today near to xvhere it was formed. Several criterea related to the agent of movement could be used to classify the nature of the sediment; (1) undisturbed (the sediment Cover of the Pleistocene Terrace is essentially undisturbed), (2) mixed by organisms, (3) transported by water movements (sediment found with ripple marks, etc., and (4) "Scoured" (the movement of individual particles of sediment from around larger boulders causes a slow downward movement or "Creeping" which is due to both the force of gravity and bottom currents. These observations and laboratory studies are discussed concerning their relationship to the formation of residual sediments, the direction of sand transportation, and the intensive erosion on the outer edge of the wave-cut platform found in this part of the Baltic Sea.

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National Highway Traffic Safety Administration, Washington, D.C.

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National Highway Traffic Safety Administration, Washington, D.C.

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National Highway Traffic Safety Administration, Washington, D.C.

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National Highway Safety Bureau, Washington, D.C.

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"C00-2118-0048."

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Errata slip inserted.

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Objective: Expectancies about the outcomes of alcohol consumption are widely accepted as important determinants of drinking. This construct is increasingly recognized as a significant element of psychological interventions for alcohol-related problems. Much effort has been invested in producing reliable and valid instruments to measure this construct for research and clinical purposes, but very few have had their factor structure subjected to adequate validation. Among them, the Drinking Expectancies Questionnaire (DEQ) was developed to address some theoretical and design issues with earlier expectancy scales. Exploratory factor analyses, in addition to validity and reliability analyses, were performed when the original questionnaire was developed. The object of this study was to undertake a confirmatory analysis of the factor structure of the DEQ. Method: Confirmatory factor analysis through LISREL 8 was performed using a randomly split sample of 679 drinkers. Results: Results suggested that a new 5-factor model, which differs slightly from the original 6-factor version, was a more robust measure of expectancies. A new method of scoring the DEQ consistent with this factor structure is presented. Conclusions: The present study shows more robust psychometric properties of the DEQ using the new factor structure.