Authors:R. Casañas Rivero, P. Suárez Hernández, E. Rodríguez Rodríguez, and C. Díaz Romero
Moisture, protein, starch, amylose, ash, ascorbic acid and fibre contents were determined in potato samples harvested in Tenerife belonging to eight cultivars and three species/subspecies:
chaucha, Solanum tuberosum
. There were several significant differences among the means of various chemical compounds according to cultivar, species or subspecies, local and recently imported potatoes. Mean values of moisture contents were often significantly different concerning the three species/subspecies considered. Local potatoes presented lower moisture and higher content of chemical compounds than the recently imported potatoes. After Varimax rotation, the first component was related to starch, and in a lesser extent to moisture (negatively), the second and the third components were associated to ash. Applying discriminant analysis on potato samples belonging to the spp.
, adequate separation according to the cultivars was obtained.
Authors:M. Peisach, L. Jacobson, G. Boulle, D. Gihwala, and L. Underhill
Data on the concentrations of K, Ca, Ti, Fe, Cu, Zn, Ga, Rb, Sr and Zr obtained by PIXE and of B, F, Na, Mg, Al, Si and Cu
obtained by proton-induced prompt gamma-ray spectrometry were used to characterize archaeological artefacts and source materials
by multivariate analysis. The mathematical approaches employed were cluster analysis using nearest-neighbour data, multidimensional
scaling and correspondence analysis.
Multivariate analysis of variance, based on randomization (permutation) test, has become an important tool for ecological data analyses. However, a comprehensive evaluation of the accuracy and power of available methods is still lacking. This is a thorough examination of randomization tests for multivariate group mean differences. With simulated data, the accuracy and power of randomization tests were evaluated using different test statistics in one-factor multivariate analysis of variance (MANOVA). The evaluations span a wide spectrum of data types, including specified and unspecified (field data) distributional properties, correlation structures, homogeneous to very heterogeneous variances, and balanced an unbalanced group sizes. The choice of test statistic strongly affected the results. Sums of squares between groups (Qb) computed on Euclidean distances (Qb-EUD) gave better accuracy. Qb on Bray-Curtis, Manhattan or Chord distances, the multiresponse permutation procedure (MRPP) and the sum of univariate ANOVA F produced severely inflated type I errors under increasing variance heterogeneity among groups, a common scenario in ecological data. Despite pervasive claims in the ecological literature, the evidence thus suggests caution when using test statistics other than Qb-EUD.
In this study, the microcalorimetric method was applied to investigate the activity of berberine on Shigella dysenteriae (S. dysenteriae). Heat flow power (HFP)–time curves of the growth metabolism of S. dysenteriae affected by berberine were determined using the thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode,
at 37 °C. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis
(SA) and principal component analysis (PCA), the antibacterial activity of berberine on S. dysenteriae could be accurately evaluated from the change of the two main parameters, the maximum heat flow power Pm2 and total heat output Qt: berberine at low concentration (25 μg mL−1) began to inhibit the growth of S. dysenteriae, high concentrations (50–200 μg mL−1) of berberine had strong antibacterial activity on S. dysenteriae, when the concentration of berberine was higher (250–300 μg mL−1), this antibacterial activity was stronger. All these illustrated that the antibacterial activity of berberine on S. dysenteriae was enhanced with the increase of the concentration of this compound. Berberine can be used as potential novel antibacterial
agent for treating multidrug-resistant Shigella. This work provided a useful idea of the combination of microcalorimetry and multivariate analysis for studying the activity
of other compounds or drugs on organisms.
This article aims to disentangle three explanations that have been proposed for the increased explicitness of translated English, as reflected in the more frequent use of the complementiser that in translated English texts compared to non-translated English texts. These three explanations are designated as the cognitive complexity (or processing strain) hypothesis, the pragmatic risk-aversion hypothesis and the source-language transfer hypothesis. Four comparable register-controlled corpora are used for the analysis: a corpus of English translated from Afrikaans, a corpus of written Afrikaans, and corpora of written British and native South African English. A multivariate analysis of the factors conditioning complementiser omission across the four corpora is used to test the three hypotheses proposed. The transfer hypothesis is tested by investigating whether the translation corpus demonstrates overall omission preferences that are more similar to the omission preferences of Afrikaans than of English. The cognitive complexity hypothesis is tested by investigating whether translated English is more sensitive to the complexity-related factors that are known to condition omission than non-translated English. The risk-aversion hypothesis is tested by investigating whether translations opt for the communicatively and normatively “safer” choice of including the complementiser in contexts where non-translated writing would typically omit it, and therefore demonstrate less sensitivity to register and frequency effects than non-translated English. The findings of the study provide strong evidence against the transfer hypothesis and find stronger support for the pragmatic risk-aversion hypothesis although the cognitive complexity hypothesis cannot be ruled out.
, no scientific study has been reported on the activity of Curcumin against food-borne pathogens. In this study, we evaluated the antimicrobial activity of Curcumin against S. aureus by microcalorimetry coupled with multivariateanalysis
Franjić, J. (1996): Multivariateanalysis of leaf properties in the common oak (Quercus robur L., Fagaceae) populations of Posavina and Podsavina in Croatia. - Ann. Forest. 21 (2): 23-60.
Multivariateanalysis of leaf properties
Authors:C. Díaz Romero, S. Tort, E. Díaz, and J.P. Pérez-Trujillo
Samples of sweet wines from the Canary Islands belonging to the Denominations of Origin of La Palma and Lanzarote islands were analysed in relation to chemical parameters. The main chemical parameters analysed demonstrated that these wines fulfil all the legal requirements, since the content of all components tested falls below the maximum concentration admissible. Applying techniques of multivariate analysis (principal component, discriminant and cluster analysis), a complete differentiation could be achieved between the wines according to the island of production using only alcohol degree and isobutanol, which are chemical parameters related to the elaboration process.