Estrutura e algumas propriedades ópticas de difenilfosfinatos de terras-raras

Coordination compounds of trivalent lanthanides cations with diphenylphosphinate are originated from direct reaction between a lanthanide salt and diphenylphosphinic acid. These complexes have peculiar and intriguing features, as (i) quickly obtainment through wet process precipitation, (ii) appreciable thermal stability, similar to inorganic phosphates, (iii) polymeric structure, and consequently, (iv) low solubility in both polar and non-polar solvents. Nowadays, coordination polymers are classified as coordination networks or, in case of porous materials, as metal-organic frameworks (MOFs). By this study, we aim to determine some optical properties of rare-earth diphenylphosphinate (RE = La3+, Eu3+, Gd3+, Lu3+) and conduct an updated classification of these compounds, bringing more details of its structure and the possible proposal of new materials with applications in lighting, detection of ionizing radiation and magnetism. The complexes of trivalent rare-earth cation with diphenylphosphinate were prepared by direct mixture of diphenylphosphinic acid with rare-earth metal chloride, both in ethanolic solution. The solution of diphenylphosphinic acid was kept in a beaker under constant stirring with pH measurements of the solution and gadolinium chloride solution was then dripped slowly with the aid of a burette until its complete addition; the following metal:ligand molar ratios were tested: 1:1, 1:2, 1:3, 2:1 e 3:1. The compounds were characterized by spectroscopic and structural techniques. By Fourier Transform Infrared Spectroscopy (FT-IR), it was possible to check the total ionization of diphenylphosphinic acid in synthesized complexes, confirmed by the absence of the band type A, B, C related to ѵ(O-H) of the acid (2663 cm-1, 2168 cm-1, 1684 cm-1), as well as the disappearance of ѵ(P-OH)=961 cm-1. Furthermore, the occurrence of bands shifts of ѵ(POO-) [symmetrical and asymmetrical] of...

Ecologia alimentar de Tatu-Peba, Euphractus sexcinctus (Linnaeus, 1758), na Fazenda Nhumirim, Pantanal da Nhecolância, MS

Studies on feeding ecology are important tools for the understanding of feeding strategies and niche dynamics. Information on the type of food consumed, how, and where it is acquired, enable the elucidation of species behavioral, evolutionary and ecological aspects. The diet study based on fecal material enables a low-cost, informative research and avoids the sacrifice of animals. The general aim of this study is to characterize the diet of Euphractus sexcinctus, the yellow-armadillo, based on fecal samples, to contribute with additional information on their feeding habits. The study was undertaken at the Nhumirim ranch, Pantanal da Nhecolândia, MS, during the months of February and March, 2014. The fecal material was collected during the manual capture of the animals and oven dried at 60°C. The food items found in the feces were sorted using a magnifying glass and separated in the following categories: plant matter, invertebrates and soil. Invertebrates were identified to the order level and the plant matter to the lowest taxonomic level possible. Aiming to evaluate the invertebrate availability in the soil, pitfall traps were installed next to the location where individuals were captured, during the months of April and May. We were able to estimate the frequency with which item was consumed during the studied period, and if there is a relationship between the frequency of consumed invertebrates and their availability environment. Among the analyzed samples, we could observe the frequency of occurrence (FO) of plant matter, invertebrates and soil in all the samples. The main invertebrate orders found in the samples were: Coleoptera, Orthoptera and Hymenoptera, with FO of 100%, 100% and 87,5%, respectively. Seeds were found in 100% of the samples. The FO of the Byrsonima orbignyana was high (62,5%), and evidences the potential of the yellow-armadillos as seed dispersers. The use of other techniques, such as the micro-histological...

Ecologia, consumo e sustentabilidade

O Desenvolvimento Sustentável tem sido pauta de diversos encontros globais que tentam solucionar as crises ambientais que vêm ocorrendo nas últimas décadas. Este trabalho tem como objetivo analisar as relações entre os impasses identificados na concepção de Desenvolvimento Sustentável e o modelo de desenvolvimento econômico capitalista tal como está configurado pelos princípios do neoliberalismo. Partimos da hipótese da inviabilidade do Desenvolvimento Sustentável em um sistema capitalista neoliberal. Utilizamos como metodologia de análise a cartografia, por meio da qual desenhamos as paisagens emergentes na dinâmica do poder ao indicar os limites do modelo de desenvolvimento econômico. Contrapomos as deficiências do modelo de desenvolvimento econômico com as premissas do que poderiam caracterizar o Desenvolvimento Sustentável. Desenvolvemos algumas reflexões acerca da sociedade de consumo e seus impactos na natureza. Apresenta-se as linhas de pensamento ecológico que discutem as maneiras de solucionar os problemas ambientais. Exercícios educacionais podem ser usados para a formação do compromisso de cada sujeito com a construção da comunidade. Refletir apenas nas contradições sociais não resolverá completamente a pressão exercida sobre os recursos naturais. A natureza não pode ser vista como um simples objeto estático que só se realiza a partir do trabalho humano, sua dinâmica deve ser considerada em sua totalidade. A sociedade não pode continuar a desenvolver meios de produção que aumentam a exploração da natureza. Uma nova estrutura social deve ser pensada, indo além das concepções marxistas e naturalistas, que promova justiça social e ambiental