Refinement Step For Parameter Estimation In The Crs Method

The Common Reflection Surface (CRS) method is a powerful extension of the well established Common Midpoint (CMP) method in the sense that it is able to accept at each trace location on the zero-offset (ZO) section to be constructed, reflection data from source and receiver pairs that are arbitrarily located around that point. The CRS method uses the general hyperbolic moveout, that depends, in the 2D situation considered in this work, on three parameters. One of these parameters is the classical NMO velocity. As in the single-parameter CMP method, the CRS parameters or attributes are estimated by a direct application of suitable coherence analysis to the input multicoverage data. The estimation of the three CRS parameters is generally performed in two steps. The first step has a global character and aims in obtaining an initial estimate of the parameters. The second step has a local character, trying to refine the previous initial values to more accurate values. Here we focus on the refinement step assuming that initial estimates have been already provided. We review and compare three of these methods and compare their performances on illustrative synthetic and real data examples. Comparisons with the application of the conventional CMP method are also provided.213275286BIRGIN, E. et al. Restricted optimization as a due to last and accurate implementation of the common reflection surface stack method. Journal of Applied Geophysics, [S.I.], v. 42, p. 143-155, 1999CASTLE, R. J. A theory of normal move out. Geophysics, [S.I.], v. 59, p. 983-999, 1994CHIRA-OLIVA, P. et al. Formula for a 2D curved measurement surface and finite-offset reflections. Journal of Seismic Eylorotion, [S.I.], v. 10, p. 245-262, 2001GARABITO, G., (2001) Empilhamento de superfícies de reflexão comum: Uma nova seqüência de processamento usando otimização global e local. 2001, , Tese (Doutorado)-Universidade Federal do Pará, BelémGILL, P. E.MURRAY, W.WRIGHT, M. H. Pratical optimization. [S.I.]: Academic Press, 1981HUBRAL, P. Computing true amplitude reflections in a laterally inhomogeneous earth. Geophysics, [S.I.], v. 48, p. 1051-1062, 1983MANN, J. Extensions and application of the common reflection surface stack method. 2002. Thesis (PhD)-University of Karlsruhe, [S.I.], 2002MÜLLER, J. The common reflection surface stack method: seismic imaging without explicit knowledge of the velocity model. 1999. Thesis (PhD)-University of Karlsruhe, [S.I.], 1999NEIDEL, N.TANER, M. Semblance and other coherency measures for multichannel data. Geophysics, [S.I.], v. 36, p. 482-497, 197

Emergence of classicality in small number entangled systems

We show the transition from a fully quantized interaction to a semiclassical one in entangled small number quantum systems using the quantum trajectories approach. In particular, we simulate the microwave Ramsey zones used in Rydberg atom interferometry, filling in the gap between the strongly entangling Jaynes Cummings evolution and the semiclassical rotation of the atomic internal states. We also correlate the information flowing with leaking photons to the entanglement generation between cavity field and flying atom and detail the roles played by the strong dissipation and the external driving force in preserving atomic coherence through the interaction.Comment: 4 pages, 6 figure

Conteúdos de NPK em biomassa de espécies de azolla cultivadas em várzea do Rio Guamá, em Belém, PA.

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Is Gastroparesis Found More Frequently in Patients with Cystic Fibrosis? A Systematic Review

Cystic fibrosis (CF) is associated with different gastrointestinal motility disturbances and syndromes. We aim to assess gastric emptying in patients with CF compared to healthy controls by a systematic review of existing literature. Medical databases and abstracts from major gastroenterology and CF meetings were reviewed. Emptying times in CF patients were compared with healthy controls using random effects models. Subgroup analysis stratified results by age and diagnostic modality. Nineteen studies from 7 countries included 574 subjects (359 CF patients and 215 controls). Using pooled analysis frequency of gastroparesis was high (38%, 95% CI 30–45%) but results were highly dependent on the diagnostic modality. Delayed gastric emptying is more common in CF compared to general population. Scintigraphy identified rapid gastric emptying in a subgroup of CF patients, but this finding disappeared with adequate pancreatic enzyme replacement and after other diagnostic modalities were included

Structural and Biochemical Characterization of AidC, a Quorum-Quenching Lactonase With Atypical Selectivity

Quorum-quenching catalysts are of interest for potential application as biochemical tools for interrogating interbacterial communication pathways, as antibiofouling agents, and as anti-infective agents in plants and animals. Herein, the structure and function of AidC, an N-acyl-l-homoserine lactone (AHL) lactonase from Chryseobacterium, is characterized. Steady-state kinetics show that zinc-supplemented AidC is the most efficient wild-type quorum-quenching enzymes characterized to date, with a kcat/KM value of approximately 2 × 106 M–1 s–1 for N-heptanoyl-l-homoserine lactone. The enzyme has stricter substrate selectivity and significantly lower KM values (ca. 50 μM for preferred substrates) compared to those of typical AHL lactonases (ca. >1 mM). X-ray crystal structures of AidC alone and with the product N-hexanoyl-l-homoserine were determined at resolutions of 1.09 and 1.67 Å, respectively. Each structure displays as a dimer, and dimeric oligiomerization was also observed in solution by size-exclusion chromatography coupled with multiangle light scattering. The structures reveal two atypical features as compared to previously characterized AHL lactonases: a “kinked” α-helix that forms part of a closed binding pocket that provides affinity and enforces selectivity for AHL substrates and an active-site His substitution that is usually found in a homologous family of phosphodiesterases. Implications for the catalytic mechanism of AHL lactonases are discussed

CD47 expression is decreased in hematopoietic progenitor cells in patients with myelofibrosis

Myelofibrosis (MF) is characterized by increased circulating hematopoietic progenitor cells (HPCs), abnormal cytokine levels, and the survival advantage of neoplastic progenitors over their normal counterparts, which leads to progressive disappearance of polyclonal hematopoiesis. CD47 is a surface glycoprotein with many functions, such as acting as a phagocytosis inhibitor of the expressing cell, that is increased in normal hematopoietic stem and progenitor cells mobilized into the blood and several human cancer-initiating cells, such as in acute myeloid leukemia. We compared CD47 expression in hematopoietic stem and progenitor cells of patients with MF and controls and found it to be decreased in progenitors of MF. Exposure of control HPCs to the cytokines transforming growth factor β and stromal-derived factor 1, which are important regulators of hematopoietic stem cell cycling and are overexpressed in patients with MF, did not modulate CD47 expression

Local seismic cultures: the use of timber frame structures in the south of Portugal

Given the fact that using timber frame structures has proven to improve the seismic behavior of vernacular architecture, as has been reported in past earthquakes in many countries, its preservation as a traditional earthquake resistant practice is important. This paper firstly intends to evaluate whether the use of timber frames as a traditional seismic resistant technique for vernacular architecture in the South of Portugal, traditionally a seismic region, is still active. Secondly, the city of Vila Real de Santo António was selected as a case study because it also followed a Pombaline development contemporary to the reconstruction of Lisbon. The plan included the provision of timber frame partition walls for some of the buildings and, thus, an overview of the type of constructions originally conceived is provided. Finally, the alterations done in the original constructions and the current state of the city center are described and the effect of these changes on the seismic vulnerability of the city is discussed.The authors wish to express their gratitude to the Portuguese Science and Technology Foundation (FCT) for the scholarship granted in the scope of the research project 'SEISMIC-V-Vernacular Seismic Culture in Portugal' (PTDC/ATP-AQI/3934/2012)

Produtividade econômica e componentes da produção de espigas verdes de milho em função da adubação nitrogenada.

Foi avaliado, durante dois anos, o efeito de doses de nitrogênio (N) na produtividade de espigas verdes de milho e em componentes da sua produção. Cinco doses de N (0, 60, 120, 180 e 240 kg ha-1) aplicadas em cobertura foram testadas num delineamento experimental de blocos casualizados, com quatro repetições. Foram avaliadas a produção e o número de espigas comerciais com palha por hectare, peso das espigas com e sem palha, comprimento e diâmetro de espigas sem palha e relação espiga com palha/palha. Aumentos na produtividade de espigas comerciais com palha com a aplicação de N foram encontrados, sendo estimadas as máximas produtividades de 13,52 t ha-1 com a dose de 157 kg ha-1 de N (primeiro ano) e de 14,86 t ha-1 com a dose de 177 kg ha-1 de N (segundo ano). Os aumentos na produtividade de espigas não foram devido aos aumentos do número de espigas por área e do comprimento destas, que não foram afetados pela adubação nitrogenada. Diferentemente da relação espiga/palha, o peso e o diâmetro das espigas foram influenciados pela elevação das doses de N. Foi proposta uma tabela de recomendação de adubação nitrogenada nos moldes de preços preestabelecidos de N e de espigas