A Simple, Inexpensive, and Reliable Method for Measuring Brønsted-Acid Site Densities in Solid Acids

A method based on amine decomposition has been developed for measuring the Brønsted-acid site densities using a standard, tubular reactor with an on-line gas chromatograph (GC). After exposing a sample to n-propylamine vapor and flushing it in flowing He at 473 K, the sample was ramped in flowing He to 773 K while trapping the products in the GC sample loop using liquid nitrogen. Site densities were determined from the quantity of propene formed by the decomposition of the n-propylammonium ions via the Hofmann-elimination reaction. The use of small amounts of sample was shown to be important for elimination of secondary products. The method was tested using H-ZSM-5, H-FER, H-MOR, and H-Y zeolites, as well as a γ-Al2O3 sample, and shown to give essentially exact agreement with temperature-programmed-desorption (TPD) and thermogravimetric analysis (TGA) measurements of n-propylamine performed in vacuum

Implication of the overlap representation for modelling generalized parton distributions

Based on a field theoretically inspired model of light-cone wave functions, we derive valence-like generalized parton distributions and their double distributions from the wave function overlap in the parton number conserved s-channel. The parton number changing contributions in the t-channel are restored from duality. In our construction constraints of positivity and polynomiality are simultaneously satisfied and it also implies a model dependent relation between generalized parton distributions and transverse momentum dependent parton distribution functions. The model predicts that the t-behavior of resulting hadronic amplitudes depends on the Bjorken variable x_Bj. We also propose an improved ansatz for double distributions that embeds this property.Comment: 15 pages, 8 eps figure

Reação ao mosaico-comum de cultivares de trigo do ensaio estadual do Rio Grande do Sul, em 2019.

No Brasil, o mosaico-comum do trigo ocorre principalmente no Rio Grande do Sul, em Santa Catarina e no sul do Paraná. Originalmente atribuído ao Soil-borne wheat mosaic virus (SBWMV, Virgaviridae) (Caetano, 1982), demonstrou-se que, no Brasil, uma nova espécie de vírus está associada à virose, o Wheat stripe mosaic virus (WhSMV, Benyviridae) (Valente et al., 2019). Este vírus é transmitido por organismo eucarioto residente no solo e parasita obrigatório de raízes de plantas, denominado Polymyxa graminis (Caetano et al., 1978; Valente et al., 2019).bitstream/item/214658/1/ComTec373-Douglas-Lau.pd

Caracterização da reação de cultivares de trigo do ensaio estadual do Rio Grande do Sul 2020 ao mosaico-comum.

O mosaico-comum do trigo é uma virose frequente em áreas tritícolas da Região Sul do Brasil. O agente causal, wheat stripe mosaic virus (WhSMV, Benyviridae), é transmitido por microrganismo residente no solo e parasita obrigatório de raízes de plantas, denominado Polymyxa graminis (Cercozoa). A resistência genética é a principal medida de controle a ser adotada em áreas contaminadas. Esse trabalho caracteriza a reação e o dano à produtividade das principais cultivares de trigo atualmente comercializadas, auxiliando na tomada de decisão quanto ao seu emprego em áreas com histórico dessa doença.bitstream/item/224686/1/ComTec-384-o.pd

Reação de genótipos de trigo ao mosaico comum - análise de dados 2010.

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Reação de genótipos de trigo ao BYDV - PAV, agente causal do nanismo amarelo: análise de dados 2010.

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Rotterdam Aphasia Therapy Study (RATS) - 3: " The efficacy of intensive cognitive-linguistic therapy in the acute stage of aphasia"; design of a randomised controlled trial

Background: Aphasia is a severely disabling condition occurring in 20 to 25% of stroke patients. Most patients with aphasia due to stroke receive speech and language therapy. Methodologically sound randomised controlled trials investigating the effect of specific interventions for patients with aphasia following stroke are scarce.

The gas distribution in the outer regions of galaxy clusters

We present the analysis of a local (z = 0.04 - 0.2) sample of 31 galaxy clusters with the aim of measuring the density of the X-ray emitting gas in cluster outskirts. We compare our results with numerical simulations to set constraints on the azimuthal symmetry and gas clumping in the outer regions of galaxy clusters. We exploit the large field-of-view and low instrumental background of ROSAT/PSPC to trace the density of the intracluster gas out to the virial radius. We perform a stacking of the density profiles to detect a signal beyond r200 and measure the typical density and scatter in cluster outskirts. We also compute the azimuthal scatter of the profiles with respect to the mean value to look for deviations from spherical symmetry. Finally, we compare our average density and scatter profiles with the results of numerical simulations. As opposed to some recent Suzaku results, and confirming previous evidence from ROSAT and Chandra, we observe a steepening of the density profiles beyond \sim r500. Comparing our density profiles with simulations, we find that non-radiative runs predict too steep density profiles, whereas runs including additional physics and/or treating gas clumping are in better agreement with the observed gas distribution. We report for the first time the high-confidence detection of a systematic difference between cool-core and non-cool core clusters beyond \sim 0.3r200, which we explain by a different distribution of the gas in the two classes. Beyond \sim r500, galaxy clusters deviate significantly from spherical symmetry, with only little differences between relaxed and disturbed systems. We find good agreement between the observed and predicted scatter profiles, but only when the 1% densest clumps are filtered out in the simulations. [Abridged]Comment: The data for the average profiles and individual clusters can be downloaded at: http://www.isdc.unige.ch/~deckert/newsite/The_Planck_ROSAT_project.htm