Brownian Diffusion
Mostrando 1-12 de 46 artigos, teses e dissertações.
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1. MODELAGEM E PREVISÃO DO COMPORTAMENTO DE PREÇOS DA COMMODITY CAFÉ ARÁBICA: UMA ABORDAGEM PELA METODOLOGIA DE SANJIV DAS / MODELING AND FORECASTING THE BEHAVIOUR OF ARABIC COFFEE COMMODITYS PRICES: AN APPROACH BY THE METHODOLOGY OF SANJIV DAS
The agribusiness has great importance for the Brazilian economy, representing a significative share of GDP and total exports of the country. Like other production processes inserted in an environment of uncertainty, the agricultural activity needs instruments that minimize the risk, especially, the risk of price and assist in decision-making process of agent
Publicado em: 2008
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2. NUMERICAL SIMULATION OF WAX DEPOSITION IN PETROLEUM LINES: ASSESSEMENT OF MOLECULAR DIFFUSION AND BROWNIAN DIFFUSION MECHANISMS / SIMULAÇÃO NUMÉRICA DA DEPOSIÇÃO DE PARAFINA EM DUTOS DE PETRÓLEO: AVALIAÇÃO DOS MECANISMOS DE DIFUSÃO MOLECULAR E DIFUSÃO BROWNIANA
Wax deposition is one of the major critical operational problems in crude oil pipelines operating in cold environments. Therefore, accurate prediction of the wax deposition is crucial for the efficient design of subsea lines. Unfortunately, wax deposition is a complex process for which the mechanisms are still not fully understood. Aiming at the identificati
Publicado em: 2007
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3. Stochastic optimal control of jumping Markov parameter processes with applications to finance.
This thesis is concerned with the study of the classical intertemporal continuous time optimal portfolio problem in the switching diffusion market and the problem of optimal control of the switching reserves of an insurance company. The switching diffusion market is a jumping Markov parameter diffusion market which has two independent sources of uncertaintie
Publicado em: 2002
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4. Brownian motion in biological membranes.
Brownian motion (diffusion) of particles in membranes occurs in a highly anisotropic environment. For such particles a translational mobility (independent of velocity) can be defined if the viscosity of the liquid embedding the membrane is taken into account. The results of a model calculation are presented. They suggest that for a realistic situation transl
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5. DNA transport by a micromachined Brownian ratchet device
We have micromachined a silicon-chip device that transports DNA with a Brownian ratchet that rectifies the Brownian motion of microscopic particles. Transport properties for a DNA 50-mer agree with theoretical predictions, and the DNA diffusion constant agrees with previous experiments. This type of micromachine could provide a generic pump or separation com
The National Academy of Sciences.
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6. Brownian dynamics simulations of probe and self-diffusion in concentrated protein and DNA solutions.
We have developed a Brownian dynamics algorithm for simulating probe and self-diffusion in concentrated solutions of DNA and protein. In these simulations, proteins are represented as spheres with radii given by their hydrodynamic radii, while DNA is modeled as a wormlike chain of hydrodynamically equivalent spherical frictional elements. The molecular inter
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7. Weighted-ensemble Brownian dynamics simulations for protein association reactions.
A new method, weighted-ensemble Brownian dynamics, is proposed for the simulation of protein-association reactions and other events whose frequencies of outcomes are constricted by free energy barriers. The method features a weighted ensemble of trajectories in configuration space with energy levels dictating the proper correspondence between "particles" and
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8. Brownian dynamics simulations of protein folding: Access to milliseconds time scale and beyond
Protein folding occurs on a time scale ranging from milliseconds to minutes for a majority of proteins. Computer simulation of protein folding, from a random configuration to the native structure, is nontrivial owing to the large disparity between the simulation and folding time scales. As an effort to overcome this limitation, simple models with idealized p
The National Academy of Sciences.
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9. Confined lateral diffusion of membrane receptors as studied by single particle tracking (nanovid microscopy). Effects of calcium-induced differentiation in cultured epithelial cells.
The movements of E-cadherin, epidermal growth factor receptor, and transferrin receptor in the plasma membrane of a cultured mouse keratinocyte cell line were studied using both single particle tracking (SPT; nanovid microscopy) and fluorescence photobleaching recovery (FPR). In the SPT technique, the receptor molecules are labeled with 40 nm-phi colloidal g
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10. Stochastic Simulation of Signal Transduction: Impact of the Cellular Architecture on Diffusion
The transduction of signals depends on the translocation of signaling molecules to specific targets. Undirected diffusion processes play a key role in the bridging of spaces between different cellular compartments. The diffusion of the molecules is, in turn, governed by the intracellular architecture. Molecular crowding and the cytoskeleton decrease macrosco
The Biophysical Society.
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11. Kinetics of protein-protein association explained by Brownian dynamics computer simulation.
Protein-protein bond formations, such as antibody-antigen complexation or aggregation of protein monomers into dimers and larger aggregates, occur with bimolecular rate constants on the order of 10(6) M-1.s-1, which is only 3 orders of magnitude slower than the diffusion-limited Smoluchowski rate. However, since the protein-protein bond requires rotational a
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12. Constrained diffusion or immobile fraction on cell surfaces: a new interpretation.
Protein lateral mobility in cell membranes is generally measured using fluorescence photobleaching recovery (FPR). Since the development of this technique, the data have been interpreted by assuming free Brownian diffusion of cell surface receptors in two dimensions, an interpretation that requires that a subset of the diffusing species remains immobile. The