Antimony glasses with large nonlinear refractive indices, small two-photon absorption coefficients and ultrafast response at telecom wavelengths

Nonlinear (NL) optical properties of antimony oxide based glasses (AG) were characterized for excitation wavelengths from 800 to 1600 m. The NL refractive indices, n2, and the two-photon absorption (TPA) coefficient, β, have been evaluated using the Z-scan technique. Values of n2≈ 10-15 - 10-14 cm2/W of electronic origin were measured and negligible TPA coefficients (β < 0.003 cm/GW) were determined. The response time of the nonlinearity is faster than 100 fs as determined using the Kerr shutter technique. The figure-of-merit usually considered for all-optical switching, T = 2βλ/n2 , indicates that AG are very good materials for ultrafast switches at telecom wavelengths. © 2007 IEEE.

Age-related differences in time-limit performance and force platform-based balance measures during one-leg stance

Poor posture control has been associated with an increased risk of falls and mobility disability among older adults. This study was conducted to assess the test-retest reliability and sensitivity to group differences regarding the time-limit (TLimit) of one-leg standing and selected balance parameters obtained with a force platform in older and young adults. A secondary purpose was to assess the relationship between TLimit and these balance parameters. Twenty-eight healthy older adults (age: 69±5years) and thirty young adults (age: 21±4years) participated in this study. Two one-leg stance tasks were performed: (1) three trials of 30s maximum and (2) one TLimit trial. The following balance parameters were computed: center of pressure area, RMS sway amplitude, and mean velocity and mean frequency in both the anterio-posterior and medio-lateral directions. All balance parameters obtained with the force platform as well as the TLimit variable were sensitive to differences in balance performance between older and young adults. The test-retest reliability of these measures was found to be acceptable (ICC: 0.40-0.85), with better ICC scores observed for mean velocity and mean frequency in the older group. Pearson correlations coefficients (r) between balance parameters and TLimit ranged from -0.16 to -0.54. These results add to the current literature that can be used in the development of measurement tools for evaluating balance in older and young adults. © 2013 Elsevier Ltd.

Estudo da influência da granulometria no comportamento reológico de polpa de bauxita e no fator de atrito

O presente trabalho apresenta estudos de caracterização reológica e determinações de fatores de atrito em três polpas de bauxita, originárias da Mina de Miltônia, Paragominas – Pará, resultantes de condições operacionais com graus diferentes de moagem. Deste modo, a diferenciação básica entre as mesmas reside na distribuição granulométrica. O objetivo é fazer uma proposta de revisão da especificação granulométrica do produto (polpa de bauxita para o mineroduto), permitindo uma comparação com as polpas do projeto (planta piloto) e da operação atual (usina de beneficiamento) quanto a resposta a alterações, principalmente, da viscosidade e fatores de atrito. A polpa proposta incorpora um percentual maior de finos (< 10 microns) em relação as demais polpas. Os benefícios possibilitarão ganhos de recuperação com a incorporação desta parcela de finos, a qual atualmente é descartada para a bacia de rejeitos. O material foi caracterizado por análises granulométricas da série Tyler, físicas e físico-químicas, microscopia eletrônica de varredura (MEV) e espectrometria de raios-x dispersiva em energia (EDS). Utilizando-se de um viscosímetro de cilindros coaxiais, tipo Searle, abordo use os aspectos reológicos destas polpas, em função da sua distribuição granulométrica e da variação da concentração de sólidos. As propriedades reológicas avaliadas foram a viscosidade, a tensão de escoamento e também os comportamentos que mostram a dependência da viscosidade com o tempo de aplicação de uma taxa de cisalhamento constante, verificando-se por meio de curva de histerese, a existência ou não da tixotropia e da reopexia. Os resultados experimentais mostraram que para as polpas ensaiadas, a granulometria e a concentração de sólidos são parâmetros relevantes na determinação da viscosidade. Os testes com estas três polpas de bauxita, de granulometrias diferentes, foram realizados a concentrações pré-determinadas, de modo a determinar o modelo reológico cujos parâmetros apresentaram os melhores coeficientes de correlação (R²), sendo que os melhores ajustes encontrados foram segundo o modelo de Herschel-Bulkley. Os fatores de atrito foram obtidos por formulações que envolvem uma relação logarítmica, utilizando-se da Lei da Parede como método de obtenção das expressões aplicáveis a estes fluidos não- Newtonianos viscoplásticos, sendo comparados com os calculados pelas correlações de Dodge e Metzner e verificou-se que de uma maneira geral há a concordância entre o modelo estudado nas três polpas. A análise dos fatores de atrito na concentração de 50% de sólidos, concentração de bombeio por mineroduto, mostra que o comportamento das polpas estudadas é semelhante, com os melhores ajustes para a faixa de 10.000 a 100.000 Reynolds (faixa média de trabalho para o escoamento turbulento de polpas de minério, homogêneas e heterogêneas).

A real-time thermal field theoretical analysis of Kubo-type shear viscosity: Numerical understanding with simple examples

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação dos gradientes de velocidade médios em sistemas de câmaras em série visando atender ao critério do menor tempo de floculação total

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

On the effects of each term of the geopotential perturbation along the time I: Quasi-circular orbits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Wide localized solutions of the parity-time-symmetric nonautonomous nonlinear Schrodinger equation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A study of the errors of the averaged models in the restricted three-body problem in a short time scale

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chemical composition and in vitro digestibility of fresh sugarcane hydrolysed with calcium oxide (CaO)

The objective was to evaluate the chemical composition and in vitro digestibility of sugarcane hydrolysed with increasing doses of calcium oxide and varying air exposure times. A completely randomised, split plot design was used; the doses were allocated to the plots, and the air exposure times were allocated to the subplots, with four repetitions. The data underwent analysis of variance and were laid out according to the effect of the treatment on the components of polynomial regressions, and evaluated at the 5% probability. The increase in the dosage negatively affected the quantities of neutral-detergent fibre (NDF), acid-detergent fibre (ADF), lignin (LIG), total carbohydrates (TC), cellulose (CEL), crude protein (CP), and ether extract (EE); and positively affected the quantities of non-fibrous carbohydrates (NFC) and mineral matter (MM). The addition of calcium oxide improved the in vitro digestible dry matter (IVDMD) coefficients and was able to keep up to 72 hours. The in vitro digestibility of the neutral-detergent fibre (IVDNDF) and of the acid-detergent fibre (IVDADF) coefficients decreased when calcium oxide was added. Calcium oxide has the ability to hydrolyse the fibrous fraction and conserve chopped sugarcane. Doses of 0.5 and 1.0% lime exhibited similar results to those achieved at higher doses; therefore, higher doses are not required in the hydrolyses of sugarcane. Over time, the sugarcane deteriorates, but this deterioration is reduced by the addition of calcium oxide.

Development, validation, and application of a method for the GC-MS analysis of fipronil and three of its degradation products in samples of water, soil, and sediment

A method for the identification and quantification of pesticide residues in water, soil, and sediment samples has been developed, validated, and applied for the analysis of real samples. The specificity was determined by the retention time and the confirmation and quantification of analyte ions. Linearity was demonstrated over the concentration range of 20 to 120 µg L(-1), and the correlation coefficients varied between 0.979 and 0.996, depending on the analytes. The recovery rates for all analytes in the studied matrix were between 86% and 112%. The intermediate precision and repeatability were determined at three concentration levels (40, 80, and 120 µg L(-1)), with the relative standard deviation for the intermediate precision between 1% and 5.3% and the repeatability varying between 2% and 13.4% for individual analytes. The limits of detection and quantification for fipronil, fipronil sulfide, fipronil-sulfone, and fipronil-desulfinyl were 6.2, 3.0, 6.6, and 4.0 ng L(-1) and 20.4, 9.0, 21.6, and 13.0 ng L(-1), respectively. The method developed was used in water, soil, and sediment samples containing 2.1 mg L(-1) and 1.2% and 5.3% of carbon, respectively. The recovery of pesticides in the environmental matrices varied from 88.26 to 109.63% for the lowest fortification level (40 and 100 µg kg(-1)), from 91.17 to 110.18% for the intermediate level (80 and 200 µg kg(-1)), and from 89.09 to 109.82% for the highest fortification level (120 and 300 µg kg(-1)). The relative standard deviation for the recovery of pesticides was under 15%.

Desenvolvimento de um sistema de SHM sem fio e com compensação automática de temperatura

Pós-graduação em Engenharia Elétrica - FEIS

Observations on Chromosomes of Dicrostonyx torquatus stevensoni Nelson and Chromosomal Diversity in Varying Lemmings = Untersuchungen an den Chromosomen von Dicrostonyx torquatus stevensoni Nelson und chromosomale Unterschiede bei Halsbandlemmingen

English abstract: The cytogenetic characteristics of the varying lemming, Dicrostonyx torquatus stevensoni, (2n = 34), were investigated, and diploid chromosomal numbers were reported for four other nominal subspecies (exsul, nelsoni, richardsoni, and rubricatus) of the torquatus-group in North America. The diploid complements ranged from 30 to 44 chromosomes, and the fundamental number from 50 to 55. Chromosomal polymorphism was observed in all forms. In cross-breeding experiments, the mating of F1 progeny was not productive. The findings support the zoogeographic concept that populations of Dicrostonyx became fragmented or displaced southward during Würm time, with relict stocks persisting in unglaciated refugia or periglacial tundra. Speciation in the isolates led to chromosomal evolution, with the result that populations spreading from refugia in post-glacial time are reproductively isolated. The torquatus-group in North America appears to be a superspecies. German title: Untersuchungen an den Chromosomen von Dicrostonyx torquatus stevensoni Nelson und chromosomale Unterschiede bei Halsbandlemmingen German abstract: Die cytogenetischen Merkmale des Halsbandlemmings, Dicrostonyx torquatus stevensoni, (2n = 34) wurden eingehend untersucht, und für vier andere nordamerikanische Unterarten der torquatus-Gruppe wurden die somatischen Chromosomensätze festgestellt. Die Chromosomenzahl der untersuchten Populationen schwankte zwischen 30 und 44, der NF (Nombre Fondamental) zwischen 50 und 55. Zuchttiere der verschiedenen Populationen wurden erfolgreich gekreuzt, aber Sterilität der F1 Unterartbastarde war typisch. Die Halsbandlemminge wiesen Karyotypenverschiedenheiten auf, die sich durch Variationen des Robertsonschen Typus, Deletionen oder möglicherweise durch perizentrische Inversionen erklären. Die Ergebnisse sprechen dafür, daß das ursprüngliche Verbreitungsgebiet von Dicrostonyx in Nordamerika durch die letzte (Würm) Vereisung getrennt wurde, und daß die Reliktpopulationen die letzte Glazial-Phase in eisfreien Refugien oder in periglazialer Tundra überlebten, wo Karyotypevolution durch lokale Anpassungsbedürfnisse gefördert wurde. Die in der Postglazialzeit aus den Refugien sich verbreitenden Populationen von Dicrostonyx scheinen reproduktiv isoliert zu sein. Die torquatus-Gruppe in Nordamerika gilt also als Superspecies.

Effect of Temperature on the Degree of Conversion and Working Time of Dual-Cured Resin Cements Exposed to Different Curing Conditions

Objectives: This study evaluated the degree of conversion (DC) and working time (WT) of two commercial, dual-cured resin cements polymerized at varying temperatures and under different curing-light accessible conditions, using Fourier transformed infrared analysis (FTIR). Materials and Methods: Calibra (Cal; Dentsply Caulk) and Variolink II (Ivoclar Vivadent) were tested at 25 degrees C or preheated to 37 degrees C or 50 degrees C and applied to a similar-temperature surface of a horizontal attenuated-total-reflectance unit (ATR) attached to an infrared spectrometer. The products were polymerized using one of four conditions: direct light exposure only (600 mW/cm(2)) through a glass slide or through a 1.5- or 3.0-mm-thick ceramic disc (A2 shade, IPS e.max, Ivoclar Vivadent) or allowed to self-cure in the absence of light curing. FTIR spectra were recorded for 20 min (1 spectrum/s, 16 scans/spectrum, resolution 4 cm(-1)) immediately after application to the ATR. DC was calculated using standard techniques of observing changes in aliphatic-to-aromatic peak ratios precuring and 20-min postcuring as well as during each 1-second interval. Time-based monomer conversion analysis was used to determine WT at each temperature. DC and WT data (n=6) were analyzed by two-way analysis of variance and Tukey post hoc test (p=0.05). Results: Higher temperatures increased DC regardless of curing mode and product. For Calibra, only the 3-mm-thick ceramic group showed lower DC than the other groups at 25 degrees C (p=0.01830), while no significant difference was observed among groups at 37 degrees C and 50 degrees C. For Variolink, the 3-mm-thick ceramic group showed lower DC than the 1-mm-thick group only at 25 degrees C, while the self-cure group showed lower DC than the others at all temperatures (p=0.00001). WT decreased with increasing temperature: at 37 degrees C near 70% reduction and at 50 degrees C near 90% for both products, with WT reduction reaching clinically inappropriate times in some cases (p=0.00001). Conclusion: Elevated temperature during polymerization of dual-cured cements increased DC. WT was reduced with elevated temperature, but the extent of reduction might not be clinically acceptable.

Real-time PCR quantitation of glucocorticoid receptor alpha isoform

Abstract Background The expression of glucocorticoid-receptor (GR) seems to be a key mechanism in the regulation of glucocorticoid (GC) sensitivity and is potentially involved in cases of GC resistance or hypersensitivity. The aim of this study is to describe a method for quantitation of GR alpha isoform (GRα) expression using real-time PCR (qrt-PCR) with analytical capabilities to monitor patients, offering standard-curve reproducibility as well as intra- and inter-assay precision. Results Standard-curves were constructed by employing standardized Jurkat cell culture procedures, both for GRα and BCR (breakpoint cluster region), as a normalizing gene. We evaluated standard-curves using five different sets of cell culture passages, RNA extraction, reverse transcription, and qrt-PCR quantification. Intra-assay precision was evaluated using 12 replicates of each gene, for 2 patients, in a single experiment. Inter-assay precision was evaluated on 8 experiments, using duplicate tests of each gene for two patients. Standard-curves were reproducible, with CV (coefficient of variation) of less than 11%, and Pearson correlation coefficients above 0,990 for most comparisons. Intra-assay and inter-assay were 2% and 7%, respectively. Conclusion This is the first method for quantitation of GRα expression with technical characteristics that permit patient monitoring, in a fast, simple and robust way.

Time-variations of equivalent water heights'from Grace Mission and in-situ river stages in the Amazon basin

Gravity Recovery and Climate Experiment (GRACE) mission is dedicated to measuring temporal variations of the Earth's gravity field. In this study, the Stokes coefficients made available by Groupe de Recherche en Géodésie Spatiale (GRGS) at a 10-day interval were converted into equivalent water height (EWH) for a ~4-year period in the Amazon basin (from July-2002 to May-2006). The seasonal amplitudes of EWH signal are the largest on the surface of Earth and reach ~ 1250mm at that basin's center. Error budget represents ~130 mm of EWH, including formal errors on Stokes coefficient, leakage errors (12 ~ 21 mm) and spectrum truncation (10 ~ 15 mm). Comparison between in situ river level time series measured at 233 ground-based hydrometric stations (HS) in the Amazon basin and vertically-integrated EWH derived from GRACE is carried out in this paper. Although EWH and HS measure different water bodies, in most of the cases a high correlation (up to ~80%) is detected between the HS series and EWH series at the same site. This correlation allows adjusting linear relationships between in situ and GRACE-based series for the major tributaries of the Amazon river. The regression coefficients decrease from up to down stream along the rivers reaching the theoretical value 1 at the Amazon's mouth in the Atlantic Ocean. The variation of the regression coefficients versus the distance from estuary is analysed for the largest rivers in the basin. In a second step, a classification of the proportionality between in situ and GRACE time-series is proposed.