Práticas e custos de produção para implantação de bosques de Tecas (Tectona grandis) em pastagens de Roraima.

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Thermoremanence anomaly in Fe-Zr(B,Cu) Invar metallic glasses: Volume expansion induced ferromagnetism

We report the existence of a thermally induced sharp increase of thermoremanence around the Curie temperature of Invar-like Fe-Zr(B,Cu) soft magnetic glasses. Neutron-diffraction measurements indicate that a true enhancement of the average local magnetic moment, rather than only a change in the domain structure, occurs. Such enhancement has been tentatively attributed to the increasing volume expansion that takes place beyond the Curie temperature and reinforces ferromagnetism in some low-density clusters

Direct measurements of the correlation between reentrant ferromagnetism and lattice expansion in FeCuZr alloys

Amorphous metastable alloy of nominal composition [Fe_(0.5)Cu_(0.5)]_(87)Zr_(13) has been synthesized by high-energy ball milling. The alloy exhibit a ferromagnetic behavior with a Curie Temperature of T_(C)=255 K, as determined from low-field measurements whereas no transition to a paramagnetic state is observed under high- enough applied magnetic fields. The evolution of hysteresis loops with temperature as well as thermoremanence measurements indicate an anomalous magnetic behavior characterized by a spontaneous increase in the magnetization values as well as by a magnetic hardening when the temperature is increased above T_(C). These effects are strongly correlated with a dilation of the Fe-Fe nearest-neighbor distances, as determined from extended x-ray absorption fine structure (EXAFS) studies. EXAFS results indicate an almost negligible thermal expansion at temperatures below T_(C) while normal thermal expansion takes place at higher temperatures. Such expansion seems to promote a reinforcement of the ferromagnetic interactions among Fe-Fe atoms that would account for the observed spontaneous increase in the magnetization as well as for the evolution of the coercive field

Desafios do projeto transição produtiva e serviços ambientais na qualificação de políticas públicas voltadas ao setor rural.

Três medidas político-institucionais ocorridas no Brasil nas duas últimas décadas devem ser destacadas: (1) Lei 12.651/2012 (Novo Código Florestal), (2) Projeto de Lei (PL) 792/2007 (Serviços Ambientais) e (3) Lei 9.126/1995 (Taxa de Juros de Longo Prazo). Mas a falta de informações cientificamente validadas impede a operacionalização de incentivos econômicos para transição produtiva com pagamento de serviços ambientais. Nesse sentido, a Embrapa e entidades parceiras conceberam o Projeto Transição Produtiva e Serviços Ambientais, com o objetivo geral de "gerar e validar instrumentos e metodologias para apoiar políticas públicas de incentivo econômico a processos de transição produtiva de Sistemas Produtivos Integrados (SPIs) com capacidade de geração de renda e prestação de serviços ambientais em escala de paisagem rural". A fase I do projeto será executada entre 09/2013 e 09/2017, tendo como resultados esperados (1) validação científica de desenhos agronômicos de SPIs, (2) validação científica de coeficientes financeiros para potencializar adoção de SPIs via crédito rural, (3) validação científica de indicadores de serviços ambientais prestados e valoração de serviços ambientais por SPIs para viabilizar rebate ecológico no crédito rural e comercialização de produtos em mercados institucionais com preços diferenciados, (4) validação participativa de indicadores de serviços ambientais e de metodologia de certificação de serviços ambientais para atestar condicionalidades em políticas públicas e reduzir custos de transação do PSA, (5) análise comportamental sobre adoção de SPIs para subsidiar recomendações técnicas de TT e ATER e (6) disponibilização de banco de dados de acesso público

Magnetic properties of ZnO nanoparticles

We experimentally show that it is possible to induce room-temperature ferromagnetic-like behavior in ZnO nanoparticles without doping with magnetic impurities but simply inducing an alteration of their electronic configuration. Capping ZnO nanoparticles (similar to 10 nm size) with different organic molecules produces an alteration of their electronic configuration that depends on the particular molecule, as evidenced by photoluminescence and X-ray absorption spectroscopies and altering their magnetic properties that varies from diamagnetic to ferromagnetic-like behavior

Blockade of T-cell activation by dithiocarbamates involves novel mechanisms of inhibition of nuclear factor of activated T cells.

Dithiocarbamates (DTCs) have recently been reported as powerful inhibitors of NF-kappaB activation in a number of cell types. Given the role of this transcription factor in the regulation of gene expression in the inflammatory response, NF-kappaB inhibitors have been suggested as potential therapeutic drugs for inflammatory diseases. We show here that DTCs inhibited both interleukin 2 (IL-2) synthesis and membrane expression of antigens which are induced during T-cell activation. This inhibition, which occurred with a parallel activation of c-Jun transactivating functions and expression, was reflected by transfection experiments at the IL-2 promoter level, and involved not only the inhibition of NF-kappaB-driven reporter activation but also that of nuclear factor of activated T cells (NFAT). Accordingly, electrophoretic mobility shift assays (EMSAs) indicated that pyrrolidine DTC (PDTC) prevented NF-kappaB, and NFAT DNA-binding activity in T cells stimulated with either phorbol myristate acetate plus ionophore or antibodies against the CD3-T-cell receptor complex and simultaneously activated the binding of AP-1. Furthermore, PDTC differentially targeted both NFATp and NFATc family members, inhibiting the transactivation functions of NFATp and mRNA induction of NFATc. Strikingly, Western blotting and immunocytochemical experiments indicated that PDTC promoted a transient and rapid shuttling of NFATp and NFATc, leading to their accelerated export from the nucleus of activated T cells. We propose that the activation of an NFAT kinase by PDTC could be responsible for the rapid shuttling of the NFAT, therefore transiently converting the sustained transactivation of this transcription factor that occurs during lymphocyte activation, and show that c-Jun NH2-terminal kinase (JNK) can act by directly phosphorylating NFATp. In addition, the combined inhibitory effects on NFAT and NF-KB support a potential use of DTCs as immunosuppressants

Risk factors for bronchiolitis hospitalization during the first year of life in a multicenter Italian birth cohort

BACKGROUND: Respiratory Syncytial Virus (RSV) is one of the main causes of respiratory infections during the first year of life. Very premature infants may contract more severe diseases and 'late preterm infants' may also be more susceptible to the infection. The aim of this study is to evaluate the risk factors for hospitalization during the first year of life in children born at different gestational ages in Italy. METHODS: A cohort of 33-34 weeks gestational age (wGA) newborns matched by sex and age with two cohort of newborns born at 35-37 wGA and > 37 wGA were enrolled in this study for a three-year period (2009-2012). Hospitalization for bronchiolitis (ICD-9 code 466.1) during the first year of life was assessed through phone interview at the end of the RSV season (November-March) and at the completion of the first year of life. RESULTS: The study enrolled 2314 newborns, of which 2210 (95.5 %) had a one year follow-up and were included in the analysis; 120 (5.4 %) were hospitalized during the first year of life for bronchiolitis. Children born at 33-34 wGA had a higher hospitalization rate compared to the two other groups. The multivariate analysis carried out on the entire population associated the following factors with higher rates for bronchiolitis hospitalization: male gender; prenatal treatment with corticosteroids; prenatal exposure to maternal smoking; singleton delivery; respiratory diseases in neonatal period; surfactant therapy; lack of breastfeeding; siblings <10 years old; living in crowded conditions and/or in unhealthy households and early exposure to the epidemic RSV season. When analysis was restricted to preterms born at 33-34 wGA the following variables were associated to higher rates of bronchiolitis hospitalization: male gender, prenatal exposure to maternal smoking, neonatal surfactant therapy, having siblings <10 years old, living in crowded conditions and being exposed to epidemic season during the first three months of life. CONCLUSION: Our study identified some prenatal, perinatal and postnatal conditions proving to be relevant and independent risk factors for hospitalization for bronchiolitis during the first year of life. The combination of these factors may lead to consider palivizumab prophylaxis in Italy

Graphene Photonics and Optoelectronics

The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential to be in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultra-wide-band tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light emitting devices, to touch screens, photodetectors and ultrafast lasers. Here we review the state of the art in this emerging field.Comment: Review Nature Photonics, in pres

Factores de calidad de un programa de Inglés como Medio de Instrucción asociados con la satisfacción de los estudiantes

This study examines the association between key quality factors of an English as a Medium of Instruction (EMI) program delivered at a Spanish university with the students’ satisfaction. The significant growth of demand and offer of bilingual and plurilingual studies in Higher Education in the last decade in many non-Anglo-Saxon countries, recommends conducting more evaluation research studies aimed at measuring quality and impact of EMI programs on students’ performance and satisfaction. To respond to that need, this ex-post facto research study included a sample of 131 self-selected students. The dependent variable student satisfaction was measured with a questionnaire (α=0.82 and a ω= 0.85) delivered through a computer-assisted web interviewing technique. Nonparametric regression analysis results confirm partially two out of the four hypotheses tested with an average of the mean estimate of 3.7 (on a 5 points scale) and the (only) average marginal significant effect of teachers teaching practices estimated to be 0.7, p < 0.01. The model (M6) with all predictions and controls explains 40.69% of the variation of the dependent variable. Finally, some conclusions and recommendations are drawn to increase future students’ satisfaction about this type of Higher Education.Este estudio examina la asociación entre factores clave de la modalidad de enseñanza denominada inglés como medio de instrucción (EMI por sus siglas en inglés) en un Grado de Educación Primaria de una universidad española y la satisfacción de los estudiantes. El crecimiento importante de la demanda y oferta de programas plurilingües en la Educación Superior en la última década en muchos países no anglosajones recomienda realizar más estudios de evaluación de la calidad y el impacto de los programas EMI en el rendimiento y satisfacción de los estudiantes. Este estudio adopta un diseño ex-post facto en una muestra de 131 estudiantes auto seleccionados. La variable dependiente satisfacción de los estudiantes se midió mediante un cuestionario  (α=0.82 and a ω= 0.85) administrado online. La regresión no paramétrica confirma parcialmente dos de las hipótesis planteadas con un valor medio de 3.72 puntos (en una escala de 5 puntos) y un efecto marginal significativo en la variable enseñanza de los profesores en el aula de 0.7, p < 0.01. El modelo (M6) con todos los predictores y controles explica el 40.69% de la variabilidad de la variable dependiente. Finalmente, se proponen algunas recomendaciones dirigidas a mejorar los niveles de satisfacción del estudiantado