NMR and rheological study of Aloe barbadensis partially acetylated glucomannan

AbstractThe structural and rheological properties of the Aloe extract (AE) and the polysaccharidic fraction (PF) obtained from the leaves pulp of Aloe barbadensis Miller were investigated. Structural analyses carried out by composition, methylation analysis and NMR spectroscopy showed that PF is mainly constituted by a partially acetylated 4-linked β-d-glucomannan. The acetyl groups are located at C-2, C-2 and C-3, C-3 and/or C-6. The acetylation pattern of this type of polysaccharide was for the first time established using bidimensional NMR analyses. AE and PF aqueous solutions at 25°C showed a non-Newtonian behavior (with pseudoplastic characteristics), however PF showed higher apparent viscosity than AE. Dynamic oscillatory analyses showed that both samples, at the same concentration, behaved as a concentrated solution. PF presented higher values of G′ compared with those of AE and this behavior could be consequence of its higher content in partially acetylated glucomannan

Gambling as a teaching aid in the introductory physics laboratory

Dice throwing is used to illustrate relevant concepts of the statistical theory of uncertainties, in particular the meaning of a limiting distribution, the standard deviation, and the standard deviation of the mean. It is an important part in a sequence of especially programmed laboratory activities, developed for freshmen, at the Institute of Physics of the University of S˜ao Paulo. It is shown how this activity is employed within a constructive teaching approach, which aims at a growing understanding of the measuring processes and of the fundamentals of correct statistical handling of experimental data

Gambling as a teaching aid in the introductory physics laboratory

Dice throwing is used to illustrate relevant concepts of the statistical theory of uncertainties, in particular the meaning of a limiting distribution, the standard deviation, and the standard deviation of the mean. It is an important part in a sequence of especially programmed laboratory activities, developed for freshmen, at the Institute of Physics of the University of S˜ao Paulo. It is shown how this activity is employed within a constructive teaching approach, which aims at a growing understanding of the measuring processes and of the fundamentals of correct statistical handling of experimental data

HERDABILIDADES E CORRELAÇÕES DA PRODUÇÃO DO FEIJÃO E DOS SEUS COMPONENTES PRIMÁRIOS, NAS ÉPOCAS DE CULTIVO DA PRIMAVERA-VERÃO E DO VERÃO-OUTONO HERITABILITIES AND CORRELATIONS OF COMMON BEAN YIELD AND ITS PRIMARY COMPONENTS, IN THE SPRING-SUMMER AND SUMMER-FALL CULTIVATION SEASONS

Este trabalho teve como objetivo estimar parâmetros genéticos em populações F2 do feijoeiro (Phaseolus vulgaris L.), cultivadas em duas épocas tradicionais no Estado de Minas Gerais. Foi realizado o cruzamento entre os cultivares 'Ouro 1919' e 'Milionário 1732', e as populações genitoras, F1 e F2 foram cultivadas na primavera-verão e no verão-outono. Nas duas épocas, as estimativas de herdabilidades foram baixas para todos os caracteres e o número de vagens por planta apresentou as maiores correlações fenotípicas e de ambiente com a produção de grãos.<br>This work aimed to estimate genetic parameters in F2 populations of the common bean (Phaseolus vulgaris L.), cultivated in two traditional seasons in Minas Gerais State (Brazil). The cultivars 'Ouro 1919' and 'Milinário 1732' were crossed, and the parental, F1 and F2 populations were cultivated in the spring-summer and summer-fall. In the two cultivation seasons, the heritabilities were low for all characters, while the number of pods per plant showed the greatest phenotypic and environmental correlations with grain yield

Componentes da produção, produtividade de grãos e características tecnológicas de cultivares de feijão Yielding components and technological characters of common bean cultivars

A utilização de cultivares com elevado potencial produtivo, adaptados ao local de cultivo e de boas características culinárias são de suma importância à cadeia produtiva do feijão. O objetivo deste trabalho foi avaliar o comportamento de cultivares de feijão (Phaseolus vulgaris L.) do grupo comercial carioca, identificando aqueles superiores quanto aos componentes da produção, produtividade de grãos, e às características tecnológicas, na semeadura "das águas" de 2000. O delineamento experimental foi o de blocos ao acaso, com 15 tratamentos, constituídos pelas cultivares: Carioca, Pérola, IAC-Carioca SH, IAC-Carioca Eté, IAC-Carioca Pyatã, Carioca Precoce, IAC-Carioca Aruã, FT-Bonito, Rudá, Aporé, Princesa, IAPAR 14, IAPAR 80, IAPAR 81 e Porto Real, com quatro repetições. A massa de cem grãos e o número de grãos por vagem são os componentes de maior influência na produtividade de grãos de cultivares de feijão. As cultivares Aporé, Carioca Precoce e Rudá, destacam-se com produtividade de grãos acima de 3.500 kg ha-1. As características tecnológicas dos grãos das cultivares Carioca, IAPAR 80 e IAPAR 81, são maiores.<br>High yielding potential and proper cooking characters are the main desirable factors to be taken into account in the choise of new common bean cultivars. In this research work, the yielding components considered were number of pods/plant, number of grains/pod and 100 grain-mass. As to the tecnological characters, grain crude protein content, cooking time and hydration ability were measured. A randomized complete block design, with four replications, was set up in which 15 common bean cultivars were checked for the above mentioned parameters (Carioca, Pérola, IAC Carioca, IAC Carioca Eté, IAC Carioca Pyatã, Carioca Precoce, IAC Carioca Aruã, FT Bonito, Rudá, Aporé, Princesa, IAPAR 14, IAPAR 80, IAPAR 81 and Porto Real). Grain yileding potentials above 3,500 kg ha-1 were observed in the cultivars Aporé, Carioca Precoce and Rudá with superior cooking parameters being detected in the cultivars Carioca, IAPAR 80 and IAPAR 81