Consulta: subjectFacets:"Polarity"
Registros recuperados: 2
Data/hora: 10/06/2024 08:40:45

Contents of total phenolics and flavonoids in and antioxidant activity of Ilex paraguariensis leaves
Provedor de dados: 86
Autores: Bisognin,Dilson Antônio; Luz,Leandro Vinícius da; Lencina,Kelen Haygert; Santos,Clarissa Obem dos; Sautter,Cláudia Kaehler.
Abstract: The objective of this work was to evaluate different solvents and times in the ultrasound-assisted extraction of polyphenols, in order to quantify the total phenolic and flavonoid contents in and the antioxidant activity of mate (Ilex paraguariensis) leaves. The experiment was carried out in a completely randomized design, in a 8x3 (solvent x time of extraction) factorial arrangement. The solvent extractors were distilled water and aqueous solutions of ethanol, acetone, and methanol, acidified or not with hydrochloric acid, and the time of ultrasound-assisted extractions were 15, 30, and 45 min. All extractions were finished with a mechanical agitation of 30 min. Samples treated with acidified hydroalcoholic solvents resulted in higher values of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mate; Polarity; Polyphenols; Solvents.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2019000101601

Polarity in DEA Models
Provedor de dados: 31
Autores: Agrell,   Per J.; Bogetoft,   Peter; Tind,   Jorgen.
This article discusses models in data envelopment analysis (DEA) relaxing the standard convexity assumptions. The basic model treats mutually incomparable pairs of sets to be generated by a procedure proposed earlier. Each pair consists of a consumption set and a production set of feasible input-output combinations. Two fundamental operations by the procedure are based on intersection and convex hull generation in the input-output space. A polarity analysis is performed which, subject to the usual assumptions about free disposability and nonnegativity, appears fruitful to do in the framework of blocking and antiblocking sets. It is shown how this leads to an interchange of the above operations extending some classical results from convex analysis. The last...
Tipo: Working or Discussion Paper
Palavras-chave: Data Envelopment Analysis; Polarity; Research Methods/ Statistical Methods.
Ano: 2000
URL: http://purl.umn.edu/24188