Metal-insulator transition in Nd1−x_{1-x}Eux_{x}NiO3_{3} compounds

Polycrystalline Nd$_{1-x}$Eu$_{x}$NiO$_3$ ($0 \leq x \leq 0.5$) compounds were synthesized in order to investigate the character of the metal-insulator (MI) phase transition in this series. Samples were prepared through the sol-gel route and subjected to heat treatments at $\sim$1000 $^\circ$C under oxygen pressures as high as 80 bar. X-ray Diffraction (XRD) and Neutron Powder Diffraction (NPD), electrical resistivity $\rho(T)$, and Magnetization $M(T)$ measurements were performed on these compounds. The results of NPD and XRD indicated that the samples crystallize in an orthorhombic distorted perovskite structure, space group $Pbnm$. The analysis of the structural parameters revealed a sudden and small expansion of $\sim$0.2% of the unit cell volume when electronic localization occurs. This expansion was attributed to a small increase of $\sim$0.003 \AA{} of the average Ni-O distance and a simultaneous decrease of $\sim$$- 0.5^\circ$ of the Ni-O-Ni superexchange angle. The $\rho(T)$ measurements revealed a MI transition occurring at temperatures ranging from $T_{\rm MI}\sim 193$ to 336 K for samples with $x = 0$ and 0.50, respectively. These measurements also show a large thermal hysteresis in NdNiO$_{3}$ during heating and cooling processes suggesting a first-order character of the phase transition at $T_{\rm MI}$. The width of this thermal hysteresis was found to decrease appreciably for the sample Nd$_{0.7}$Eu$_{0.3}$NiO$_{3}$. The results indicate that cation disorder associated with increasing substitution of Nd by Eu is responsible for changing the first order character of the transition in NdNiO$_{3}$.Comment: 19 pages, 9 figure

Doubly Periodic Instanton Zero Modes

Fermionic zero modes associated with doubly periodic SU(2) instantons of unit charge are considered. In cases where the action density exhibits two `instanton cores' the zero mode peaks on one of four line-segments joining the two constituents. Which of the four possibilities is realised depends on the fermionic boundary conditions; doubly periodic, doubly anti-periodic or mixed.Comment: 12 pages, 4 figure

Linguistic validation of cystic fibrosis quality of life questionnaires

OBJECTIVE: The purpose of this study was to validate the Portuguese translations of four cystic fibrosis quality of life questionnaires (CFQ). The first three were developed for patients with cystic fibrosis aged from 6 to 11 years, from 12 to 13 years and 14 years or more, while the fourth was developed for the parents of patients aged 6 to 13 years. MATERIAL AND METHODS: The four CFQ translations contained from 35 to 50 questions covering nine domains and were validated as follows: translation from English to Portuguese, pilot application, back translation and then approval by the author of the English versions. The four translations were applied to 90 stable patients (30 from each age group) and the parents of patients aged 6-13 years (n = 60), on two occasions with a 13 to 17 day interval. Intraclass Correlation Coefficients (ICC) were used to measure reproducibility. This study was approved by the Commission for Ethics in Research at the institution. RESULTS:Reproducibility was good (ICC = 0.62 to 0.99) for the four translations in all domains, with the exceptions of the Digestion domain for the 6 to 11 and 12 to 13 years age groups with ICC = 0.59 and 0.47, respectively and the Social Role domain for the 14 and over age group (ICC = -0.19 ) CONCLUSION: The translation and cultural adaptation for Brazil resulted in four CFQ versions that are easy to understand and offer good reproducibility.OBJETIVO: O propósito deste estudo foi validar em português as quatro versões de questionários de qualidade de vida em fibrose cística, desenvolvidos para pacientes com fibrose cística de 6 a 11 anos, de 12 a 13 e mais de 14 anos, e para os pais de pacientes de 6 a 13 anos. MATERIAL E MÉTODOS: A validação das quatro versões de questionários de qualidade de vida em fibrose cística (de 35 e 50 questões, abrangendo nove domínios) constou de: versão inglês-português, aplicação-piloto, tradução retrógrada e aprovação da autora da versão inglesa. As quatro versões foram aplicadas a 90 pacientes estáveis (30 de cada grupo etário) e aos pais de doentes de 6-13 anos (n = 60), em duas entrevistas, com intervalo de 13-17 dias. Foi avaliada a reprodutibilidade pelo coeficiente de correlação intraclasse (CCI). O estudo foi aprovado pela comissão de ética em pesquisa da instituição. RESULTADOS: A reprodutibilidade foi boa (CCI = 0,62 a 0,99) para as quatro versões, em todos os domínios, exceto o digestivo (CCI = 0,59 e CCI = 0,47) para os grupos etários de 6 a 11 e 12 a 13 anos, respectivamente, e domínio papel social (CCI = -0,19 ) para o grupo acima de 14 anos. CONCLUSÃO: A tradução e a adaptação à língua e à cultura brasileiras das quatro versões de questionários de qualidade de vida em fibrose cística mostraram-se de fácil entendimento e boa reprodutibilidade.Universidade de São Paulo Faculdade de Medicina Departamento de PediatriaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaFaculdade de Medicina do ABCUNIFESP-EPM Centro de Reabilitação PulmonarUniversidade de São Paulo Faculdade de Medicina Hospital das ClínicasUniversity of Miami Department of PsychologyUNIFESP, EPM, Centro de Reabilitação PulmonarSciEL

‘Candidatus Phytoplasma stylosanthis’, a novel taxon with a diverse host range in Australia, characterised using multilocus sequence analysis of 16S rRNA, secA, tuf, and rp genes

In Australia, Stylosanthes little leaf (StLL) phytoplasma has been detected in Stylosanthes scabra Vogel, Arachis pintoi Krapov, Saccharum officinarum L., Carica papaya L., Medicago sativa L., and Solanum tuberosum L. The 16S rRNA gene sequence of StLL phytoplasma strains from S. scabra, C. papaya, S. officinarum and S. tuberosum were compared and share 99.93–100 % nucleotide sequence identity. Phylogenetic comparisons between the 16S rRNA genes of StLL phytoplasma and other ‘Candidatus Phytoplasma’ species indicate that StLL represents a distinct phytoplasma lineage. It shares its most recent known ancestry with ‘Ca. Phytoplasma luffae’ (16SrVIII-A), with which it has 97.17–97.25 % nucleotide identity. In silico RFLP analysis of the 16S rRNA amplicon using iPhyClassifier indicate that StLL phytoplasmas have a unique pattern (similarity coefficient below 0.85) that is most similar to that of ‘Ca. Phytoplasma luffae’. The unique in silico RFLP patterns were confirmed in vitro. Nucleotide sequences of genes that are more variable than the 16S rRNA gene, namely tuf (tu-elongation factor), secA (partial translocation gene), and the partial ribosomal protein (rp) gene operon (rps19-rpl22-rps3), produced phylogenetic trees with similar branching patterns to the 16S rRNA gene tree. Sequence comparisons between the StLL 16S rRNA spacer region confirmed previous reports of rrn interoperon sequence heterogeneity for StLL, where the spacer region of rrnB encodes a complete tRNA-Isoleucine gene and the rrnA spacer region does not. Together these results suggest that the Australian phytoplasma, StLL, is unique according to the International Organization for Mycoplasmology (IRPCM) recommendations. The novel taxon ‘Ca. Phytoplasma stylosanthis’ is proposed, with the most recent strain from a potato crop in Victoria, Australia, serving as the reference strain (deposited in the Victorian Plant Pathology Herbarium as VPRI 43683)

Synchronous-scan fluorescence and the complexation of copper (II) ions by humic substances

Two fluorescence bands were detected using synchronous-scan fluorescence on samples of terrestrially derived humic substances (lex/lem 380/398, 440/458 nm) without the addition of copper. A third band (lex/lem 502/520 nm) was detected after severe quenching of the second band (lex/lem 440/458 nm) caused by additions of copper. A more energetic band (lex/lem 333/351 nm) is present in marine DOM, but absent in the terrestrial material. The effects of copper on both the intensity and shape of the synchronous-scan fluorescence spectra and this technique s potential use as a tracer are discussed.A fluorescência de substâncias húmicas de origem terrestre foi investigada através da técnica de fluorescência sincronizada, e as amostras mostraram duas bandas principais (lex/lem 380/398, 440/458 nm) quando analisadas sem adição do metal paramagnético cobre. Uma terceira banda (lex/lem 502/520 nm) foi detectada após severa extinção de fluorescência da segunda banda causada pela adição de cobre. Uma outra banda, mais energética (lex/lem 333/351 nm) foi detectada em amostras marinhas, porém ausente do material de origem terrestre. Os efeitos de cobre sobre a intensidade e forma do espectro de fluorescência sincronizado e a utilização desta técnica como marcadores são discutidas.339342Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Corporate Bankruptcy of Portuguese Firms

Over the time has been increasing the interest in understanding the subjects of insolvency and bankruptcy due to its consequences for the country’s economic performance, and, actually, to its importance in the actual economic European context. The present work studies the evolution of bankruptcy of Portuguese fi rms in the last two decades, and obtains a set of macroeconomic factors which can explain this occurrence. It was considered the period 1990-2009, and the methodology used was a regression model including variables considerate in several empirical studies sustained in the literature review. The obtained results pointed to the relevance of macroeconomic variables as most signifi cant explanatory variables for the Portuguese case

Heterotic Compactification, An Algorithmic Approach

We approach string phenomenology from the perspective of computational algebraic geometry, by providing new and efficient techniques for proving stability and calculating particle spectra in heterotic compactifications. This is done in the context of complete intersection Calabi-Yau manifolds in a single projective space where we classify positive monad bundles. Using a combination of analytic methods and computer algebra we prove stability for all such bundles and compute the complete particle spectrum, including gauge singlets. In particular, we find that the number of anti-generations vanishes for all our bundles and that the spectrum is manifestly moduli-dependent.Comment: 36 pages, Late