Spin-phonon coupling in Gd(Co1/2Mn1/2)O3 perovskite

We have investigated the temperature-dependent Raman-active phonons and the magnetic properties of Gd(Co1/2Mn1/2)O3 perovskite ceramics in the temperature range from 40 K to 300 K. The samples crystallized in an orthorhombic distorted simple perovskite, whose symmetry belongs to the Pnma space group. The data reveals spin-phonon coupling near the ferromagnetic transition occurring at around 120 K. The correlation of the Raman and magnetization data suggests that the structural order influences the magnitude of the spin-phonon coupling.Comment: 3 Figures, suplementary materia

Soil organisms in organic and conventional cropping systems.

Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas

Coleoptera of Brazil: what we knew then and what we know now. Insights from the Catálogo Taxonômico da Fauna do Brasil

ABSTRACT In 2000, Cleide Costa published a paper presenting the state of knowledge of the Neotropical Coleopte ra, with a focus on the Brazilian fauna. Twenty-four years later, thanks to the development of the Coleoptera section of the Taxonomic Catalog of the Brazilian Fauna (CTFB - Catálogo Taxonômico da Fauna do Brasil) through the collaboration of 100 coleopterists from all over the globe, we can build on Costa’s work and present an updated overview of the state of knowledge of the beetles from Brazil. There are currently 35,699 species in 4,958 genera and 116 families known to occur in the country, including representatives of all extant suborders and superfamilies. Our data show that the Brazilian beetle fauna is the richest on the planet, concentrating 9% of the world species diversity, with some estimates accounting to up to 15% of the global total. The most diverse family in numbers of genera is Cerambycidae (1,056 genera), while in number of species it is Chrysomelidae (6,079 species). Conotrachelus Dejean, 1835 (Curculionidae) is the most species-rich genus, with 570 species. The French entomologist Maurice Pic is the author who has contributed the most to the naming of species recorded from Brazil, with 1,794 valid names in 36 families, whereas the Brazilians Ubirajara R. Martins and Maria Helena M. Galileo are the only ones among the top-ten authors to have named species in the 21st century. Currently, approximately 144 new species of Brazilian beetles are described each year, and this average is projected to increase in the next decade to 180 species per year, or about one new Brazilian beetle every two days

Ba-doping effects on structural, magnetic and vibrational properties of disordered La2NiMnO6

Barium-doped La2NiMnO6 double perovskites have been investigated in order to elucidate the role of the B-site doping on its magnetic, dielectric and vibrational properties. In all cases, we have obtained a non-linear dependence with the Barium content signaling that a 5% molar doping renders the maximum B-site ordering. By analyzing a series of gradually doped samples, we have found that the effective magnetic moment in the B-site can be enhanced by a factor of nearly 100% by 5% Ba doping. In order to exclude oxidation state induce changes, XPS and XANES measurements have been carried out concluding that nickel or manganese oxidation states ratio are not modified by the Ba doping. Raman spectroscopy correlates Ba doping with vacancies thus attributing to the latter the role of primary source for structural defects in Ba-La2NiMnO6 samples. This manuscript summarizes key consequences of the B-site ordering which are crucial to address the optimization of the magneto-electric coupling in Ba-La2NiMnO6 double perovskites

Nested-PCR using MPB64 fragment improves the diagnosis of pleural and meningeal tuberculosis Nested-PCR usando o fragmento MPB64 melhora o diagnóstico da tuberculose pleural e meníngea

Fluids in which Mycobacterium tuberculosis are seldom found, such as pleural and cerebrospinal liquids, are good candidates to be studied using PCR techniques. We detail our experience with a PCR assay applied to pleural and cerebrospinal fluids using the primer MPB64. Seventy three specimens were analyzed: 30 pleural fluids (PF), 26 pleural biopsies (PB) and 17 cerebrospinal fluids (CSF). The gold standard for the diagnosis of tuberculous meningitis was the positive culture for M. tuberculosis in CSF. Tuberculous pleural effusion was diagnosed when cultures of PF and/or PB were positive for M. tuberculosis, or the PB histology showed granulomas. Our results, compared to the gold standards employed, showed a sensitivity of 70%, specificity of 88%, positive predictive value of 82% and negative predictive value of 80%. The high specificity of the MPB64 fragment while still retaining a good sensitivity makes it very well suited for pleural and cerebrospinal tuberculosis diagnosis.<br>O Mycobacterium tuberculosis é raramente encontrado em fluidos como o líquido pleural e o cérebroespinhal, tornando estas localizações de difícil diagnóstico. Apresentamos nossa experiência com uma técnica de PCR aplicada a líquido pleural e cerebroespinhal com o uso do primer MPB64. Sessenta e três espécimes foram analisados: 30 líquidos pleurais (PF), 26 biópsias pleurais (PB) e 17 líquidos cerebroespinhais (CSF). O gold standard para o diagnóstico de meningite tuberculosa foi a cultura positiva para M. tuberculosis no CSF. Tuberculose pleural era diagnosticada quando culturas do PF e/ou PB eram positivas para M. tuberculosis, ou a histologia da PB mostrava granulomas. Nossos resultados, comparados aos gold standards empregados, mostram sensitividade de 70%, especificidade de 88%, valor preditivo positivo de 82% e valor preditivo negativo de 80%. A elevada especificidade e boa sensibilidade do fragmento MPB64 o transformam em um bom parâmetro para o diagnóstico de tuberculose pleural e do líquido cérebroespinhal