PARTICLE SIZE DISTRIBUTION CORRECTION METHOD USING A SIMULATED ANNEALING TECHNIQUE

The procedure for obtaining the particle size distribution by visual inspection of a sample involves stereological errors, given the cut of the sample. A cut particle, supposedly spherical, with radius R, will be counted as a circular particle with radius r, r≤R. The difference between r and R depends on how far from the center of the sphere the cut was performed. This introduces errors when the extrapolation of the properties from two to three dimensions during the analysis of a sample. The usual method is to correct the distribution by probabilistic functions, which have large errors. This paper presents a method to reduce the error inherent to this problem. The method is to compute a simulation of the preparation process in a sample whose structure can be described by non-penetrating spheres of various diameters which meet a known probability distribution function, for example, a log-logistic function, or even a constant function. For each distribution radius, a number of spheres is generated and virtually cut, generating a bi-dimensional (2D) distribution. The 2D curves of the spheres distribution obtained in this simulation are compared with that obtained by the experimental procedure and then the parameters of the threedimensional distribution function are adjusted until the 2D curves are similar to the experimental one using the optimization method Simulated Annealing for the curve-fitting. In future this method will be applied to the analysis of the oil reservoir rocks

Aspectos fitossanitários da cultura de sorgo no Brasil.

bitstream/item/48139/1/Aspectos-fitossanitarios.pd

POROUS MEDIA MICROSTRUCTURE RECONSTRUCTION USING PIXEL-BASED AND OBJECT-BASED SIMULATED ANNEALING – COMPARISON WITH OTHER RECONSTRUCTION METHODS

In this contribution the issue of the stochastic reconstruction of particulatemedia from 2D photomicrographic images is addressed with particular reference to pore space connectivity. The reconstruction of porous bodies in 2D or 3D space was achieved by using simulated annealing techniques. Two methods were proposed to reconstruct a well connected pore space. The first, named PSA (Pixel-based Simulated Annealing), a pixel-movement based, three constraints were found to be necessary for  the successful reconstruction of well connected pore space: the two-pointcorrelation function, the d3-4 distance transform distribution and the  linealpath function for the pore phase. The second, named OSA (Object-based Simulated Annealing), only constrains the two-point correlation function. Following several researches which tried to reconstruct porous media using pixel-movement based simulated techniques, we propose a new parameter to add a microstructure descriptor, but we also propose a new technique, based in moving the microstructure grains (spheres) instead of the pixels. Both methods were applied to reconstruct reservoir rocks microstructures, and the 2D and 3D results were compared with microstructures reconstructed by truncated Gaussian methods. The PSA resulted in microstructures characterized by poor pore space connectivity, and by artificial patterns, while the OSA reconstructed microstructures with good pore space connectivity. These results indicate that the OSA method can reconstruct better microstructures than the present methods

Avaliação de linhagens e cultivares de feijoeiro comum para agricultura familiar em Goiás.

O objetivo deste trabalho foi selecionar cultivares e linhagens de feijoeiro comum adaptadas ao sistema de produção dos pequenos agricultores, por meio da implementação de ensaios de VCU (Valor de cultivo e uso) nas propriedades dos agricultores no estado de Goiás

Quem é quem na pesquisa da Embrapa Amazônia Oriental.

Para o cumprimento de sua missão institucional, o maior patrimônio da Embrapa Amazônia Oriental tem sido a competência de seu capital humano nas áreas de pesquisa e apoio técnico-administrativo, do qual a Empresa muito se orgulha. Por essa razão, em mais um passo no processo de abertura da Embrapa à sociedade, seu principal cliente, temos a grande satisfação de, através desta primeira edição de Quem-é-quem na pesquisa da Embrapa Amazônia Oriental, dar conhecimento público dos nomes dos pesquisadores atualmente em atividade no Centro, sua formação acadêmica, linhas de pesquisa, e áreas de conhecimento, bem como suas principais publicações nos últimos cinco anos.bitstream/item/35682/1/quem-e-quem-Cpatu.PD

Cdkn2a inactivation promotes malignant transformation of mouse immature thymocytes before the β-selection checkpoint

CDKN2A deletion is the most frequent genetic alteration in T-cell acute lymphoblastic leukemia (T-ALL), occurring across all molecular and immunophenotypic subtypes. CDKN2A encodes two functionally unrelated tumor suppressor proteins, ARF and INK4a, which are critical regulators of cell cycle and proliferation. Arf has been reported to suppress T-ALL development in post−b-selection thymocytes, but whether CDKN2A acts as a tumor suppressor gene in immature, pre−b-selection thymocytes remains to be elucidated. Resorting to a Rag2-deficient model of T-ALL, driven by the ETV6:: JAK2 fusion, we report that Cdkn2a haploinsufficiency at early stages of T-cell development facilitates leukemia developmentPPBI-POCI-01-0145-FEDER-022122; POCI-01-0145-FEDER-007274; NORTE01-0145-FEDER-000029info:eu-repo/semantics/publishedVersio

Primary and secondary scintillation measurements in a xenon Gas Proportional Scintillation Counter

NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm-1 torr-1 in the drift region, demonstrating negligible recombination luminescence. A primary scintillation yield of 81 \pm 7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72 \pm 6 eV to produce a primary scintillation photon in xenon.Comment: 16 pages, 10 figures, accepted for publication in JINS

Utilização de tecnologia alternativa para coleta de material meristemático de bananeira para estabelecimento in vitro.

Em Rondônia, a banana é a fruta de maior importância econômica e a mais produzida no Estado. Em 2006, em uma área de 5.401 ha, foram produzidas 46.117 toneladas Os principais municípios produtores são Buritis, Cacoal e Porto Velho, respectivamente. No entanto, a bananicultura no Estado enfrenta alguns problemas agrícolas: alta incidência de pragas e doenças (moleque, nematóides, mal do Panamá, Sigatokas negra e amarela, com maior destaque para a Sigatoka negra), baixo nível de tecnologia utilizado na produção e na pós-colheita e falta de capacitação dos agentes da cadeia produtiva. Assim, a seleção de variedades mostra-se como uma forma eficaz no combate a pragas e doenças. Neste sentido, o objetivo deste trabalho foi testar uma tecnologia alternativa para tornar mais simples e eficiente o processo de coleta e estabelecimento de explantes de bananeiras, contribuindo com a produção de mudas em sistemas de produção via cultura de tecidos vegetais.bitstream/CPAF-RO-2010/13267/1/ct101-banana.pd