Patterns of change in the late-Quaternary vegetation of the Western Interior of Canada

1978 ◽  
Vol 56 (17) ◽  
pp. 2177-2183 ◽  
Author(s):  
J. C. Ritchie ◽  
G. A. Yarranton

Principal components analysis (PCA) of pollen data from 14 sites reveals five types of sequence. All begin from an early spruce-dominated assemblage, now apparently extinct, with subsequent differentiation into patterns of forested and grassland vegetation. A comparison of the PCA ordinations of these subfossil zones with those of modern pollen samples illustrates the uniqueness of the early spruce zone and the similarities between subsequent zones and modern spectra. The technique demonstrates the time transgressive nature of the early spruce forest assemblage in this region.

1997 ◽  
Vol 48 (2) ◽  
pp. 215-227 ◽  
Author(s):  
Francisco Serrano ◽  
Antonio Guerra-Merchán ◽  
Carmen Lozano-Francisco ◽  
José Luis Vera-Peláez

AbstractNerja Cave is a karstic cavity used by humans from Late Paleolithic to post-Chalcolithic times. Remains of molluscan foods in the uppermost Pleistocene and Holocene sediments were studied with cluster analysis and principal components analysis, in bothQ and R modes. The results from cluster analysis distinguished interval groups mainly in accordance with chronology and distinguished assemblages of species mainly according to habitat. Significant changes in the shellfish diet through time were revealed. In the Late Magdalenian, most molluscs consumed consisted of pulmonate gastropods and species from sandy sea bottoms. The Epipaleolithic diet was more varied and included species from rocky shorelines. From the Neolithic onward most molluscs consumed were from rocky shorelines. From the principal components analysis inQ mode, the first factor reflected mainly changes in the predominant capture environment, probably because of major paleogeographic changes. The second factor may reflect selective capture along rocky coastlines during certain times. The third factor correlated well with the sea-surface temperature curve in the western Mediterranean (Alboran Sea) during the late Quaternary.


1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.


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