Being positive is not everything – experimental and computational studies on the selectivity of a self‐assembled, multiple redox‐state receptor that binds anions with up to picomolar affinities

The interaction of a redox-active trinuclear, self-assembled Ru metallomacrocycle with oxo-anions is reported and its affinity for these anions and halides in different oxidation states is calculated, revealing both high affinities (>109 M−1 for some guests) and high selectivities (a range of >107 M−1). Detailed quantum-based computational studies on the host in each of its oxidation states, revealed that it binds anion guests by a combination of non-covalent interactions, including charge-assisted hydrogen bonding and anion-π interactions

Perdas de solo, matéria orgânica e nutrientes por erosão hídrica em uma vertente coberta com diferentes quantidades de palha de cana-de-açúcar em Guariba - SP Soil, organic matter and nutrients losses by water erosion in a slope with sugarcane straw, in Guariba, State of São Paulo

A erosão em entressulcos resulta da desagregação causada pelo impacto das gotas de chuva na superfície do solo e pelo transporte superficial das partículas do solo desagregadas, onde se encontram a matéria orgânica e os nutrientes fundamentais para a produção agrícola. O presente trabalho teve como objetivo avaliar as perdas de solo, matéria orgânica e nutrientes em uma vertente localizada em uma área de Latossolo Vermelho-Amarelo distrófico, cultivada com cana-de-açúcar, que é colhida mecanicamente. As parcelas experimentais foram submetidas à ação de uma chuva simulada com intensidade de 60 mm h-1, durante 65 minutos. Foram feitas análises do sedimento erodido para a determinação do volume de solução, das perdas de solo, matéria orgânica e nutrientes. Houve maiores perdas de solo, matéria orgânica e nutrientes nos sedimentos oriundos das parcelas com 0% e 25% de cobertura por palha de cana-de-açúcar. Em média, essas perdas foram reduzidas nas parcelas com 75% e 100% de cobertura com palha de cana-de-açúcar. Os resultados permitiram concluir que uma cobertura com palha de cana-de-açúcar acima de 50%, da área colhida, reduz a perda de solo e de matéria orgânica, bem como diminui a concentração de nutrientes no sedimento erodido.<br>The interril erosion results of the disaggregation caused by the impact of the rainfall on the surface and by the superficial transport of the disaggregated soil particles, where there are the organic matter and the nutrients for the agricultural production. The present work aimed to evaluate the soil, organic matter and nutrients losses of a slope located in an area of distrofic Oxisol, cultivated with sugarcane and submitted to the automated crop. Experimental portions were submitted to the action of a simulated rain of 60 mm h-1 intensity, for 65 minutes. Analyses of the erosion sediment were made to determine the solution volume and soil, organic matter and nutrients losses. There were larger soil, organic matter and nutrients losses in the sediment of the portions with 0% and 25% of sugarcane straw coverage. On average, the losses were significantly reduced in the portions with 75% and 100% of sugarcane straw coverage. The results allowed concluding that the sugarcane straw coverage above 50%, in the crop area, reduces the soil and organic matter loss as well as the concentration of nutrients in the erosion sediment