Authors:Xinxin Zhao, Enji Jia, Weiguang Yang, Yingshan Dong, and Bao Liu
DNA methylation polymorphism among nine elite maize inbred lines was assessed by inter-simple sequence repeat (ISSR) fingerprinting on intact DNA and DNA digested by either of a pair of methylation-sensitive isoschizomers,
I. It was found that, along with distinct genetic differentiation, extensive DNA methylation polymorphism exists among the nine inbred lines. The line-specific methylation patterns are homogeneous within each line, indicating their usefulness as molecular markers for cultivar identification. DNA sequences underlying the DNA methylation variations include a high proportion of coding genes. Cluster analysis, however, indicates the existence of incongruence between DNA methylation polymorphism and known-pedigree of the maize inbred lines.
In the present study, correlations between wet gluten content, valorigraphic value and alveographic parameters (P, L, P/L, G, W) of winter wheat varieties were investigated as influenced by fertilizer and fertilizer + fungicide treatment in the years 2001 and 2002.Various correlation analyses (Pearson correlation, principal component analysis, cluster analysis, stepwise regression) evidenced that alveographic W primarily was closely related with valorigraphic value. The correlation was not close enough to allow us to estimate the alveographic W parameter on valorigraph as precisely as it is demanded by industry and trade. There was no strong correlation between wet gluten content and any other parameters involved in the study.
Authors:L. Moens, P. Roos, J. De Rudder, J. Hoste, P. De Paepe, J. Van Hende, R. Marechal, and M. Waelkens
In 94 marble samples from 4 quarry districts in Italy (Carrara) and Turkey (Proconnesus, Dokimeion, Usak), minor and trace elements were determined by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The maximum size of the calcite grains (MGS) of the rocks was measured in thin section. For 16 elements considered in this work, the concentration ranges show important inter-district overlaps; this also applies to the maximum grain size. However, the application of cluster analysis, using selected attributes, allows one to discriminate every pair of districts; 90 samples are classified correctly in all classification dendrograms.
This paper describes experimental results through multivariate statistical methods that might reveal outliers that are rarely
taken into account by analysts. The results were submitted to three procedures to detect outliers: Mahalanobis distance, MD,
cluster analysis, CA, and principal component analysis, PCA. The results showed that although CA is one of the procedures
most often used to identify outliers, it can fail by not showing the samples that are easily identified as outliers by other
methods, like MD. Mahalanobis distance proved to be the simpler application, with sensitive procedures to identify outliers
in multivariate datasets.
In Latin America, interactive science centres and museums are key institutions for science communication. In order to map
their relationship over the Internet, a Web co-link analysis was applied to 18 websites of science centres and museums affiliated
to the Network for the Popularization of Science and Technology in Latin America and the Caribbean - RedPOP. Clustering analysis,
multidimensional scaling (MDS) and an analysis of all pages with links to at least two websites were performed. Results showed
that language barriers played a prominent role in clustering, with external recognition by the target public representing
a secondary issue.
Authors:Pamela Lang, Fábio Gouveia, and Jacqueline Leta
The method of co-link was proposed in 1996 and since then it has been applied in many Webometric studies. Its definition refers
to “page co-link analysis”, as links are provided by URLs or pages. This paper presents a new methodological approach, a “site
co-link analysis”, to investigate relations in small networks. The Oswaldo Cruz Foundation institutes were used as a case
study. The results indicate that the number of co-links provided by sites led to an increase of 133% in the sample analyzed.
In a cluster analysis, three clusters were formed mainly for thematic reasons and four institutes remained isolated.
Authors:B. Zhang, Y. Li, Q. Li, B. Ma, F. Gan, Z. Zhang, H. Cheng, and F. Yang
External-beam PIXE was used for the non-destructive analysis of early glasses unearthed from the tombs of Warring States (475–221BC) and Han Dynasty (BC 206–AD 220) in south China. It was found that these glasses were basically attributed to PbO—BaO—SiO2 system and K2O—SiO2 system. The results from the cluster analysis showed that some glasses had exactly the same recipe. The source of the K2O flux and the correlation between PbO and BaO are discussed. Some archeological information is revealed.
Authors:Haiyan Hou, Hildrun Kretschmer, and Zeyuan Liu
The structure of scientific collaboration networks in scientometrics is investigated at the level of individuals by using
bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation
Index (SCI) of the years 1978–2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis
and frequency analysis of words is explored to reveal: (1) The microstructure of the collaboration network on scientists’
aspects of scientometrics; (2) The major collaborative fields of the whole network and of different collaborative sub-networks;
(3) The collaborative center of the collaboration network in scientometrics.
Authors:M. Reis, M. Freitas, H. Dung, A. Mateus, I. Paiva, M. Madruga, M. Gonçalves, L. Silva, and I. Dionísio
The main objective of this study is the elemental characterization of geomaterial samples (“soils” and Rañas), collected between 2007 and 2008, in the Morais Massif, (NE Mainland of Portugal) by using two complementary techniques:
instrumental neutron activation analysis (INAA) and high resolution gamma spectrometry. Samples granulometric fractions lower
than 63 μm were analyzed by gamma spectrometry, for artificial and natural radionuclides using HPGe detectors and by INAA,
for chemical elements at the Portuguese research reactor, RPI. Statistical analysis, such as clusters analysis and Pearson
correlations were applied to the obtained results. The enrichment factors were also calculated as an estimator of anthropogenic
inputs in relation to the average crustal abundance. Group differentiation of Rañas and “soils” is clearly shown from cluster analysis. The strong correlation factors obtained between some chemical elements
corroborates the origins and the geology/mineralogy of the area studied. The combined application of both nuclear analytical
techniques has shown their importance in providing useful information for the future site and repository performance and safety
Authors:M. Ceneviva-Bastos, L. Casatti, and V. Uieda
Many studies on Neotropical streams have reported seasonal changes in the diet of fish, although studies that evaluate the influence of these temporal differences on the entire web are very scarce. Under the hypothesis that trophic interactions and the food web structure are under seasonal influences, two forested streams (named S1 and S2) were sampled during the wet and dry periods. The samplings were conducted in August 2007 and April 2008 and included algae, macrophytes, plankton. macroinvertebrates, and fish. All heterotrophic taxa sampled were submitted to diet analysis. The similarity among samples was estimated by a cluster analysis using quantitative data of environmental variables, community attributes, and food web properties. A total of 2,250 individuals of 139 trophic species were identified. The food webs were mainly detritus-based, which resulted in a great proportion of trophic species at the first trophic level and high omnivory in all samples. All fish species were top species because they had no predators. The S1 stream, predominantly composed of a sandy substrate, presented lower abundance than the predominantly rocky S2 stream in both dry and wet periods, although richness was similar. Cluster analysis demonstrated that environmental attributes were more similar between seasons, community attributes were more similar between streams, and food web parameters were very similar (94% similarity) both between streams and seasons. Therefore, we concluded that although environmental attributes varied temporally and community attributes varied spatially, the trophic relationships and overall food web structure of these preserved streams remain similar.