Taxonomia do gênero Heliotropium L. (Heliotropiaceae) no Brasil

The taxonomy of the genus Heliotropium L. in Brazil was studied, revealing nine species and two varieties: H. amplexicaule Vahl, H. angiospermum Murray, H. curassavicum L., H. curassavicum var. argentinum I.M. Johnst., H. elongatum (Lehm.) I.M. Johnst., H. elongatum var. burchellii I.M. Johnst., H. indicum L., H. leiocarpum Morong, H. nicotianaefolium Poir., H. phylicoides Cham. and H. transalpinum Vell. Descriptions, illustrations, comments on relationships based on morphology and data on species distribution are presented.

Fast And Direct Na And K Determination In Table, Marine, And Low-sodium Salts By X-ray Fluorescence And Chemometrics.

X-ray fluorescence (XRF) is a fast, low-cost, nondestructive, and truly multielement analytical technique. The objectives of this study are to quantify the amount of Na(+) and K(+) in samples of table salt (refined, marine, and light) and to compare three different methodologies of quantification using XRF. A fundamental parameter method revealed difficulties in quantifying accurately lighter elements (Z < 22). A univariate methodology based on peak area calibration is an attractive alternative, even though additional steps of data manipulation might consume some time. Quantifications were performed with good correlations for both Na (r = 0.974) and K (r = 0.992). A partial least-squares (PLS) regression method with five latent variables was very fast. Na(+) quantifications provided calibration errors lower than 16% and a correlation of 0.995. Of great concern was the observation of high Na(+) levels in low-sodium salts. The presented application may be performed in a fast and multielement fashion, in accordance with Green Chemistry specifications.

A importância das revistas Química Nova e Journal of the Brazilian Chemical Society no crescimento da área de química no Brasil

Quimica Nova and the Journal of the Brazilian Chemical Society are two examples of successful initiatives taken by the Brazilian Chemical Society (SBQ - Sociedade Brasileira de Química), and may serve as models for the scientific societies of developing countries. Pillars of the SBQ, these two periodicals are undeniable demonstrations that idealism, utopia and dignity are the essential ingredients for transforming dreams into reality. Few believed that the Brazilian chemical community would one day have, as it does today, two scientific research periodicals indexed in the principal international data banks.

Comparação entre protocolos de determinação do limiar anaerobio e suas correlações com o desempenho aerobio em nadadores adolescentes

Universidade Estadual de Campinas . Faculdade de Educação Física