Análise granulométrica: novo método para determinar a fração argila.

Os autores apresentam um novo método para determinar argila total, na qual essa determinação é feita no 200ml da parte superior do cilindro de Koettgen (acima da torneira superior), após uma sedimentação de 90 minutos, utilizando o hidrômetro de Bouyoucos. Também fica demonstrado que os resultados obtidos com a técnica e o tempo recomendados por Bouyoucos deixam muito a desejar, principalmente com amostras ricas em silte.bitstream/item/65520/1/Analise-granulometrica-novo-metodo-para-determinar-a-fracao-argila-1968.pdfTrabalho apresentado ao XI Congresso Brasileiro de Ciência do Solo

Métodos de análise de solo.

bitstream/item/169147/1/EPFS-BT-7-1969.pd

Lyapunov Control on Quantum Open System in Decoherence-free Subspaces

A scheme to drive and manipulate a finite-dimensional quantum system in the decoherence-free subspaces(DFS) by Lyapunov control is proposed. Control fields are established by Lyapunov function. This proposal can drive the open quantum system into the DFS and manipulate it to any desired eigenstate of the free Hamiltonian. An example which consists of a four-level system with three long-lived states driven by two lasers is presented to exemplify the scheme. We have performed numerical simulations for the dynamics of the four-level system, which show that the scheme works good.Comment: 5 pages, 6 figure

On the influence of collinear surface waves on turbulence in smooth-bed open-channel flows

This work investigates how turbulence in open-channel flows is altered by the passage of surface waves by using experimental data collected with laboratory tests in a large-scale flume facility, wherein waves followed a current. Flow velocity data were measured with a laser Doppler anemometer and used to compute profiles of mean velocity and Reynolds stresses, and pre-multiplied spectra. The velocity signal containing contributions from the mean flow, wave motion and turbulence was decomposed using the empirical mode decomposition (EMD), which is considered a promising tool for the analysis of velocity time series measured in complex flows. A novel outer length scale h0 is proposed which separates the flow into two regions depending on the competition between the vertical velocities associated with the wave motion and the turbulent velocities imposed by the current. This outer length scale allows for the identification of a genuine overlap layer and an insightful scaling of turbulent statistics in the current-dominated flow region (i.e. y/h0 > 1), a new spectral signature associated with long turbulent structures (approximately 6 and 25 times the flow depth h). As the wave contribution to the vertical velocity increases, the pre-multiplied spectra reveal two intriguing features: (i) in the current-dominated flow region, the very large-scale motions (VLSMs) are progressively weakened but attached eddies are still present; and (ii) in the wave-dominated flow region (i.e. 1$]) appears. These longitudinal structures present in the wave-dominated flow region seem to share many features with Langumir-type cells

Optical mapping of neuronal activity during seizures in zebrafish

Mapping neuronal activity during the onset and propagation of epileptic seizures can provide a better understanding of the mechanisms underlying this pathology and improve our approaches to the development of new drugs. Recently, zebrafish has become an important model for studying epilepsy both in basic research and in drug discovery. Here, we employed a transgenic line with pan-neuronal expression of the genetically-encoded calcium indicator GCaMP6s to measure neuronal activity in zebrafish larvae during seizures induced by pentylenetretrazole (PTZ). With this approach, we mapped neuronal activity in different areas of the larval brain, demonstrating the high sensitivity of this method to different levels of alteration, as induced by increasing PTZ concentrations, and the rescuing effect of an anti-epileptic drug. We also present simultaneous measurements of brain and locomotor activity, as well as a high-throughput assay, demonstrating that GCaMP measurements can complement behavioural assays for the detection of subclinical epileptic seizures, thus enabling future investigations on human hypomorphic mutations and more effective drug screening methods. Notably, the methodology described here can be easily applied to the study of many human neuropathologies modelled in zebrafish, allowing a simple and yet detailed investigation of brain activity alterations associated with the pathological phenotype

Testes rápidos para estimar as necessidades em calcário de alguns solos de São Paulo

Five rapid laboratory tests for lime requirements (LR) were calibrated against a method in which soils were incubated with CaCO3 until a pH equilibrium was attained. The Woodruff and SMP methods, which estimate the LR from the pH depression of buffer solutions in soil-buffer suspensions, satisfactorily estimated the LR for pH control. The SMP buffer, as used in Ohio, gave values that were about double the true values, but was satisfactory when the amount of soil in the suspension was reduced to one-half the original amount. The LR values as measured by the acidity extracted by Co(OAc)2 at pH 7 and as estimated from base saturation-pH curves were highly correlated with LR to pH 5.5, 6.0 and 6.5 by incubation. A method based on acidity extracted by KCI and on (Ca+Mg) supply was satisfactory in the neutralization of exchangeable AI and in supplying (Ca+Mg), but gave low correlation with LR for pH control.Cinco métodos de análise rápida, objetivando a determinação da necessidade em calcário (NC) de alguns solos de São Paulo, foram testados mediante comparação com os resultados obtidos pela incubação com CaCO3, até atingir um pH de equilíbrio. Os métodos de Woodruff e SMP, que estimam a NC a partir da depressão de pH de suspensões de terra em soluções tamponizadas, estimaram satisfatoriamente as NC para o controle de pH. A solução tampão SMP, tal como é usada em Ohio, deu valores que eram quase o dobro dos valores verdadeiros, mas mostrou-se satisfatória quando a quantidade de solo na suspensão foi reduzida à metade da quantidade original. Os valores das NC, medidos pela acidez extraída por Ca(OAc), a pH 7 e estimados pelas curvas de saturação de bases e pH, mostraram alta correlação com as NC para pH 5,5, 6,0 e 6,5 determinadas por incubação. Um método baseado na acidez extraída pelo KCI e no suprimento de (Ca+Mg) mostrou-se satisfatório tanto no que respeita à neutralização do AI trocável quanto ao suprimento de (Ca+Mg), porém deu baixa correlação com os valores da NC para o controle de pH determinados por incubação

Effect of Diet and Essential Oils on the Fatty Acid Composition, Oxidative Stability and Microbiological Profile of Marchigiana Burgers

The objective of this study is to evaluate the effects of including linseed (L) or linseed plus vitamin E (LE) in the diet of Marchigiana young bulls on the oxidative stability, color measurements, microbiological profile and fatty acid composition (FA) of burgers treated with and without a blend of essential oils (Rosmarinus officinalis and Origanum vulgare var. hirtum) (EOs). For this aim, the burgers were analysed for pH, thiobarbituric-acid-reactive substance (TBARS) content, Ferric Reducing/Antioxidant Power Assay (FRAP), vitamin E and colour measurements (L, a*, b) at 3, 6, 9, 12 days of storage: the TBARs were the highest in group L compared to C and LE after 12 days of storage (0.98, 0.73, and 0.63 mg MDA/kg, respectively). The TBARS content was also influenced by the use of EO compared to burgers not treated with EO (p < 0.05). The vitamin E content was influenced by the diet (p < 0.01), but not by the EO. The meat of the L group showed the lowest value of redness (a*) compared to C and LE (p < 0.01), while the use of EO did not affect colour parameters. The microbiological profile of the burgers showed a lower Pseudomonas count for L and LE at T0 (2.82 ± 0.30 and 2.30 ± 0.52 Log CFU/g, respectively) compared to C (3.90 ± 0.38 Log CFU/g), while the EO did not influence the microbiological profile. The FA composition was analysed at 0 and 12 days. The burgers from the LE group showed the highest value of polyunsaturated FA compared to the L and C groups (p < 0.05). Our findings suggest that the inclusion of vitamin E in a concentrate rich in polyunsaturated fatty acids is useful to limit intramuscular fat oxidation and to preserve the colour stability of burgers from young Marchigiana bulls enriched with healthy fatty acids. Moreover, linseed and vitamin E had a positive effect on microbial loads and growth dynamics, containing microbial development through time