Descripción: Nitrogen compounds like urea and melamine are known to be commonly used for milk adulteration resulting in undesired intoxication; a well-known example is the Chinese episode occurred in 2008. The development of a rapid, reliable and economic test is of relevance in order to improve adulterated milk identification. Cyclic voltammetry studies using an Au working electrode were performed on adulterated and non-adulterated milk samples from different independent manufacturers. Voltammetric data and their first derivative were subjected to functional principal component analysis (f-PCA) and correctly classified by the KNN classifier. The adulterated and non-adulterated milk samples showed significant differences. Best results of prediction were obtained with first derivative data. Detection limits in milk samples adulterated with 1% of its total nitrogen derived from melamine or urea were as low as 85.0 mg·L-1 and 121.4 mg·L-1, respectively. We present this method as a fast and robust screening method for milk adulteration analysis and prevention of food intoxication. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Descripción: Cluster analysis and ordination by principal component analysis (PCA) were used to study phenetic relationships among the Argentine species of Alstroemeriaceae and to point out the characters that contribute to the differentiation between Alstroemeria L. and Bomarea Mirb. A total of 123 specimens (analysis 1) and 15 taxa (analysis 2) were examined and 46 morphological characters were used: 17 quantitative and 29 qualitative ones. The results point out the clear phenetic distinction between Alstroemeria and Bomarea species and also among species within both genera. A dendrogram produced by UPGMA cluster analysis on standardized characters and the PCA analysis show the differentiation of Bomarea species into two groups: B1 includes Bomarea stans Kränzl., B. boliviensis Baker (subgen. Sphaerine) and B. edulis (Tuss.) Herb, (subgen. Bomarea) respectively, and B2 with B. macrocephala Pax. (subgen. Wichuraea). For the Alstroemeria species, four groups are recognized: A1 is formed by Alstroemeria apertiflora Baker, A. bakeri Pax and A. isabellana Herb.; A2 comprises two subgroups, A2a: A. psittacina Lehm., A. presliana Herb, and A. aurea Graham and A2b with A. pygmaea Herb, and A. patagonica Phil, (with A. patagonica Phil. f. biflora Ravenna). A. pseudospathulata Ehr. Bayer (A3) and A. andina Phil, subsp. venustula (Phil.) Ehr. Bayer (A4) have isolated positions.

Descripción: • Background and Aims: Trees with a partial leaf-shedding pattern and other morphological features a priori considered intermediate between those of the deciduous Nothofagus antarctica (G. Forster) Oersted and the evergreen N. dombeyi (Mirb.) Oersted (Nothofagaceae) were found in natural stands. The hybridization between a deciduous and an evergreen species of Nothofagus has not been reported so far in natural communities. • Methods: The putative hybrids and the two presumed parental species were compared using 14 enzyme systems as well as shoot, leaf and reproductive morphology. • Key Results: Six enzyme systems showed good resolution (MDH-B, IDH, SKDH, 6-PGDH, GOT and PGI) and in four of them (PGI, MDH-B, SKDH and 6-PGDH) the putative hybrids showed intermediate zymogram patterns between N. antarctica and N. dombeyi. Both principal coordinates analysis on isozyme data and principal components analysis (PCA) on quantitative morphological traits of shoots and leaves separated both parental species and located the putative hybrids closer to N. antarctica than to N. dombeyi. In the PCA, the number of basal cataphylls and the length:width ratio of leaves were the variables most discriminating among shoots of the three entities. The putative hybrids were intermediate between both species regarding leaf vernation, outline and venation, variation in leaf shape (length/width) with position on the parent shoot and in staminate inflorescence and cupule morphology. For other morphological traits, the putative hybrids resembled one of the parental species or differed from both species (e.g. valve morphology). • Conclusions: Isoenzymatic and morphological data sets support the idea of the hybrid nature (probably F 1 generation) of the semi-deciduous trees found. Nothofagus antarctica and N. dombeyi are probably more closely related than previously assumed. The relevance of pollen type in revealing evolutionary relationships between Nothofagus species is supported, and that of leaf-shedding pattern is rejected. © 2004 Annals of Botany Company.