Influence of the temperature on the viscosity measurements of solutions of a soil fulvic acid

The influence of the concentration (ca. 45 to 300 mg L-1), the pH (3.0 to 8.0), the ionic strength (0.005 to 0.10 M), and the temperature (283 to 303 K) on the viscosimetric behaviour of solutions of a soil fulvic acid has been analysed, and their molecular parameters (length, thickness, and molecular volume) calculated. The results indicate that the polyelectrolytic behaviour of the fulvic acid is similar at all the temperatures, i.e., increasing the viscosity when reducing the ionic strength and to increase the temperature. With respect to the pH an initial decrease in the viscosity is obtained followed by a rise to the highest pH values. These variations have been interpreted by their molecular parameters as due to modifications of the structure of the molecules of the fulvic acid.Key words: fulvic acid, viscosity, temperature. </jats:p

Method for the differentiation of leaf litter extracts and study of their interaction with Cu(II) by molecular fluorescence

Six leaf litter extracts (LLE) (eucalyptus (Eucaliptus globulus), fern (Pteridium aquilinium), oak (Quercus robur), chestnut (Castanea sátiva), laurel (Laurus nobilis), and ulex (Ulex europoeus) canopies) were isolated following an extraction procedure similar to that used for fulvic acids (FA) and were characterized by elemental analysis and UV-Vis, FT-IR, and synchronous molecular fluorescence (SyF) spectroscopies. Moreover, information about their interaction with the Cu(II) ion in aqueous solution (100 mg yL of LLE in 0.1 M KNO3 at pH = 6) was obtained from the measurement of SyF spectra at increasing concentrations of Cu(II). These spectral sets were treated by a self-modeling mixture analysis method (SIMPLISMA) to obtain improved quenching profiles to be used in the estimation by the method of Ryan and Weber of the conditional stability constants (Kc), concentration of binding sites, and percentage of fluorescent binding sites accessible for complexation. For comparison purposes, two samples of FA extracted from two horizons of an oak forest soil (0-5 cm and 5-15 cm) were also studied. The spectroscopic data obtained for LLE and FA were different. The results suggest that LLE are characterized by relatively high concentrations of individualized simple molecules and include reactive structures (alkene and protein residues). The ratio of aliphatic yaromatic structures was higher in LLE than for FA. Both LLE and soil FA form stable complexes with Cu(II), but the logarithm of the conditional stability constant of the 1:1 complexes is larger for LLE (about 5) than for the soil FA (about 4.5).Key words: leaf litter extracts, soil fulvic acids, synchronous fluorescence, Cu(II) complexation, SIMPLISMA, spectral pattern recognition. </jats:p

Sobrepeso em crianças menores de 6 anos de idade em Florianópolis, SC Overweight in children under 6 years of age in Florianópolis, SC, Brazil

Verificou-se a prevalência de sobrepeso através do índice de peso para altura, classificação expressa em escore-Z, padrão de referência do National Center for Health Statistics, em 3 806 crianças menores de seis anos de idade, residentes no município de Florianópolis, Estado de Santa Catarina, Brasil. Obteve-se uma prevalência de 1,9% de desnutrição e 6,8% de sobrepeso, sendo este predominante em crianças residentes em áreas não carentes, do sexo feminino e menores de dois anos de idade. A prevalência de sobrepeso deste estudo foi comparada com aquelas encontradas em outras regiões do Brasil e em outros países. Aplicou-se o teste chi2 (Mantel-Haenszel), para verificar a associação de casos com sobrepeso entre áreas carentes e não carentes, sexo e faixa etária. Observou-se associação estatisticamente significante (p<0,05) entre as crianças menores de dois anos de idade, resultado semelhante ao encontrado pela Pesquisa Nacional sobre Saúde e Nutrição para o Brasil em 1989.<br>The prevalence of overweight in 3,806 children under six years of age, living in the city of Florianópolis, state of Santa Catarina, Brazil, was determined through weight for height Z-scores (National Center for Health Statistics reference). Results showed an incidence of 1.9% for malnutrition and 6.8% for overweight, and this last one predominated in female children under the age of two, living in not-so-poor areas. The prevalence of overweight in this study was compared to those found in other regions of Brazil and in other countries. The chi2 Mantel-Haenszel test was applied to verify the association of overweight occurrence with poor/not poor areas, sex and age. Statistically significant association (p<0.05) was observed among children under two years of age. This result is similar to the one found by Pesquisa Nacional sobre Saúde e Nutrição for Brazil in 1989

Publisher Correction: Whole-genome sequencing of a sporadic primary immunodeficiency cohort (Nature, (2020), 583, 7814, (90-95), 10.1038/s41586-020-2265-1)

\ua9 2020, The Author(s), under exclusive licence to Springer Nature Limited. An amendment to this paper has been published and can be accessed via a link at the top of the paper