Search Results
Abstract
We carried out instrumental neutron activation analysis (INAA) as well as k 0-based prompt gamma-ray analysis (k 0-PGA) to measure the amount of the elements in onions and studied whether the onions collected from different sites can be categorized based on the elemental concentration profile. Six elements (Na, Mg, Cl, K, Ca, Mn) and 3 elements (B, S, Cl) were measured by INAA and PGA in the onions grown in two districts, Hokkaido and Saga, in Japan, respectively. After principal component analysis, it was found that Cl was an important element to feature the producing districts of onions.
Abstract
In order to investigate the transition of tidelands, we collected sediments in Yatsu tideland and Nekozane river mouth in Tokyo Bay. The vertical distributions of elements were determined by instrumental neutron activation analysis and prompt gamma-ray analysis. In Yatsu tideland the vertical distribution changed in a great extent, which was considered as an influence of the neighboring reclamation. They were categorized into four groups, and two parameters were created by applying principal component analysis. Chemical states of iron and sulfur were also investigated by Mössbauer spectroscopy and X-ray absorption fine structure. These results show that Yatsu tideland became an anaerobic environment.
Abstract
This study explores the intellectual structure and interdisciplinary breadth of Knowledge Management in its early stage of development. Intellectual structure is established by a principal component analysis applied to an author co-citation frequency matrix. The author co-citation frequencies were derived from the 1994-1998 academic literature and captured by the single search phrase of 
Knowledge Management.
Four factors were labeled Knowledge Management, Organizational Learning, Knowledge-based Theories, and The Role of Tacit Knowledge in Organizations. The interdisciplinary breadth surrounding Knowledge Management mainly occurs in the discipline of management. Empirical evidence suggests that the discipline of Computer Science is not a key contributor as originally hypothesized.
Abstract
This paper describes the implementation of multivariate data analysis: NEURODOC applies the axial k-means method for automatic, non-hierarchical cluster analysis and a Principal Component Analysis (PCA) for representing the clusters on a map. We next introduce Artificial Neural Networks (ANNs) to extend NEURODOC into a neural platform for the cluster analysis and cartography of bibliographic data. The ANNs tested are: the Adaptive Resonance Theory (ART 1), a Multilayer Perceptron (MLP), and an associative network with unsupervised learning (KOHONEN). This platform is intended for quantitative analysis of information.
Abstract
A cocitation analysis for thirty-six journals and other publications in neural networks research and related disciplines was conducted over three consecutive time periods spanning the years 1990-early 1997. Cluster analysis and MDS maps identified groupings representing foundation research areas (physics/optics, computer engineering, neuroscience, expert systems & cognition, and perception) along with neural networks and mathematical modeling of neural systems. Principal components analysis demonstrated a similar structure, with several journals and books loading on a majority of the factors. An INDSCAL analysis showed an increasing separation between natural sciences/psychology and engineering/neural networks research from the first time period to the third.
We investigated how cluster analysis and diversity-ordering can be used for the classification of geographically and historically distinct plant and insect communities. The study sites include fens and Brachypodium pinnatum dominated grasslands. The stands of the fen vegetation type could be arranged into similar groups by cluster analysis, principal component analysis and diversity ordering techniques. In the case of the B. pinnatum dominated grasslands of diverse development, however, no groups could be differentiated on the basis of either diversity ordering or ordination. Of the various cluster analyses, the result of global optimisation was similar to those of PCA ordination and diversity ordering techniques.
Abstract
The objective of this research is to trace the sources of stream sediments in a small watershed influenced by anthropogenic and lithogenic origins identified by the spatial distributions and temporal variations of stream sediments using geochemical interpretation of the stable and radiogenic isotopes, major components, and heavy metals data and principal component analysis. To know the effects of both present and past mining, the stream sediments were sampled at the stream tributaries and sediment coring work. The spatial distributions of heavy metals clearly showed the effects of Cu and Pb–Zn mineralization zones at the site. Anthropogenic Pb was elevated at the downstream area by the stream sediments due to an active quarry. The results of principal components analysis also represent the effects of the stream sediments origins, including anthropogenic wastes and the active quarry and lithogenic sediment. Anomalous Cu, indicating the effect of past Guryong mining, was identified at the deep core sediments of 1.80–5.05 m depth. The influence of active quarry was shown in the recently deposited sediments of <1.50 m depth, which was proved by the profiles of radioactive 210Pb and stable Pb and Sr isotopes. This study suggests that the chemical studies using radiogenic and stable isotopes and heavy metals and multivariate statistical method are useful tools to discriminate the sources of stream sediments with different origins.
ICP-OES (inductively coupled plasma optical emission spectrometry) was used to determine the element content of red wines. Development of the method involves various procedures of sample handling as well as repeatability and reproducibility measurements. Measurements were made for the following 16 elements: Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn. The relative standard deviation of repeatability ranged from 0.41% (potassium) to 27% (cadmium) and that of reproducibility varied between 0.73% (boron) to 52% (cobalt). Recovery of the elements was determined by standard addition with results ranging from 90.6% (phosphorus) to 116.2% (boron). After that, 15 red wine samples were measured. Significant differences were found in the Al, B, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn (P<0.001) concentration of wine samples. Correlation studies revealed parallel changes in phosphorus-potassium, phosphorus-magnesium and zinc-manganese concentrations (r=0.857, 0.875, 0.838). According to principal component analysis, measurements of zinc-, sodium-, boron-, copper- and strontium content gave almost the same results as obtained with 16 different elements. According to a two dimensional non-linear map of absolute values of principal component analysis, wines from Szekszárd and Eger could be differentiated, whereas the analysis of wines from Villány, the Mátra Mountains and Lake Balaton showed overlapping results.
The lipophilic character of phytol derivatives has been studied using reverse-phase planar chromatographic procedures. Methanol-water and acetonitrile-water binary mixtures as mobile phases with C18 and cyano as stationary phases were used in order to determine the lipophilicity parameters and C
0. The classical values were compared with the factor scores obtained by principal component analysis based also on the TLC retention data. Moderate to high correlation between the values and slopes (specific hydrophobic surface area) was observed, which reflects the involvement of secondary interactions in the TLC retention behavior. The phytol derivatives considered in this study were screened for their antituberculosis activity against the H37Rv strain. Chromatographically obtained lipophilicity parameters were correlated with the calculated log P values and minimum inhibitory concentration (MIC) values. Principal component analysis established the dominant pattern in the chromatographic indices. Quantitative structure-retention relationship and quantitative structure-activity (antitubercular) relationship investigations were performed on the lipophilicities and molecular descriptors of phytol derivatives using partial least squares. The predicted biological activities support the fact that the chromatographic processes of the investigated phytol derivatives influence the partitioning over biomembrane and are controlled mainly by the lipophilicity.
Anthocyanin composition and profile were analysed in skin extracts from red grapes and wines of the autochthonous Croatian cultivars of Babić and Plavac mali by HPLC-DAD-MS method. Higher relative abundance of malvidin-3-monoglucoside and lower relative abundance of peonidin-3-monoglucoside and cyanidin-3-monoglucoside were identified in wine in relation to their earlier abundance in grapes. Using principal component analysis (PCA), the wine samples showed differences between wine types, although the grape samples did not show any considerable differences concerning the anthocyanin composition. The main differences between Babić and Plavac mali wines were detected in a monoglucoside acetate (malvidin-3-monoglucoside acetate), a monoglucoside-caffeoate (malvidin-3-monoglucoside caffeoate) and a group of monoglucosides (malvidin-3-monoglucoside, delphinidin-3-monoglucoside, petunidin-3-monoglucoside and peonidin-3-monoglucoside).
