Functional magnetic resonance imaging（fMRI）is one of the most commonly used methods in cognitive neuroscience on humans.In recent decades,fMRI has also been used in the awake monkey experiments to localize functiona...Functional magnetic resonance imaging（fMRI）is one of the most commonly used methods in cognitive neuroscience on humans.In recent decades,fMRI has also been used in the awake monkey experiments to localize functional brain areas and to compare the functional differences between human and monkey brains.Several procedures and paradigms have been developed to maintain proper head fixation and to perform motion control training.In this study,we extended the application of fMRI to awake cats without training,receiving a flickering checkerboard visual stimulus projected to a screen in front of them in a block-design paradigm.We found that body movement-induced non-rigid motion introduced artifacts into the functional scans,especially those around the eye and neck.To correct for these artifacts,we developed two methods：one for general experimental design,and the other for studies of whether a checkerboard task could be used as a localizer to optimize the motioncorrection parameters.The results demonstrated that,with proper animal fixation and motion correction procedures,it is possible to perform fMRI experiments with untrained awake cats.展开更多
In this paper, we establish a 1-1 correspondence between positive solutionsof one class of nonlinear differential equations and a class of harmonic functions.These results give an explicit description of E.B.Dynkin...In this paper, we establish a 1-1 correspondence between positive solutionsof one class of nonlinear differential equations and a class of harmonic functions.These results give an explicit description of E.B.Dynkin's class Ha of positive harmonic functions.展开更多
Based on the crystal structure of the vitamin B12 transporter protein of Escherichia coli(BtuCD)a system consisting of the BtuCD transmembrane domain(BtuC)and the palmitoyloleoyl phosphatidylcholine(POPC)lipid bilayer...Based on the crystal structure of the vitamin B12 transporter protein of Escherichia coli(BtuCD)a system consisting of the BtuCD transmembrane domain(BtuC)and the palmitoyloleoyl phosphatidylcholine(POPC)lipid bilayer was constructed in silica,and a more-than-57-nanosecond molecular dynamics(MD)simulation was performed on it to reveal the intrinsic functional motions of BtuC.The results showed that a stable protein-lipid bilayer was obtained and the POPC lipid bilayer was able to adjust its thickness to match the embedded BtuC which underwent relatively complicated motions.These results may help to understand the mechanism of transmembrane substrate transport at the atomic level.展开更多
The traditional Dead Reckoning algorithm predicts the future motion state based on a determined polynomial predictor,and the forecasting performance would vary with different types of motion entities.This paper propos...The traditional Dead Reckoning algorithm predicts the future motion state based on a determined polynomial predictor,and the forecasting performance would vary with different types of motion entities.This paper proposes an enhanced dead reckoning algorithm based on hybrid extrapolation models,which can be used to reduce the communication in a distributed interactive simulation.The proposed algorithm perform extrapolation using a number of candidate predictors.Its idea is based on the assumption that a complex trajectory can be decomposed into several simple trajectories.The experimental evaluations show that the enhanced Dead Reckoning algorithm provides better performance in correction data reduction and accurate estimation.展开更多
基金supported by grants from the Ministry of Science and Technology of China (2012CB825500, 2012IM030100, 2010IM030800)the National Natural Science Foundation of China (91132302, 90820307)
文摘Functional magnetic resonance imaging（fMRI）is one of the most commonly used methods in cognitive neuroscience on humans.In recent decades,fMRI has also been used in the awake monkey experiments to localize functional brain areas and to compare the functional differences between human and monkey brains.Several procedures and paradigms have been developed to maintain proper head fixation and to perform motion control training.In this study,we extended the application of fMRI to awake cats without training,receiving a flickering checkerboard visual stimulus projected to a screen in front of them in a block-design paradigm.We found that body movement-induced non-rigid motion introduced artifacts into the functional scans,especially those around the eye and neck.To correct for these artifacts,we developed two methods：one for general experimental design,and the other for studies of whether a checkerboard task could be used as a localizer to optimize the motioncorrection parameters.The results demonstrated that,with proper animal fixation and motion correction procedures,it is possible to perform fMRI experiments with untrained awake cats.
文摘In this paper, we establish a 1-1 correspondence between positive solutionsof one class of nonlinear differential equations and a class of harmonic functions.These results give an explicit description of E.B.Dynkin's class Ha of positive harmonic functions.
基金supported by the National Natural Science Foundation of China(Grant Nos 20773006 and 30670497)the Beijing Natural Science Foun-dation(Grant Nos 7082006 and 5072002)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No 200800050003)
文摘Based on the crystal structure of the vitamin B12 transporter protein of Escherichia coli(BtuCD)a system consisting of the BtuCD transmembrane domain(BtuC)and the palmitoyloleoyl phosphatidylcholine(POPC)lipid bilayer was constructed in silica,and a more-than-57-nanosecond molecular dynamics(MD)simulation was performed on it to reveal the intrinsic functional motions of BtuC.The results showed that a stable protein-lipid bilayer was obtained and the POPC lipid bilayer was able to adjust its thickness to match the embedded BtuC which underwent relatively complicated motions.These results may help to understand the mechanism of transmembrane substrate transport at the atomic level.
基金the research Project of State Key Laboratory of High Performance computing of National University of Defense Technology(No.201303-05).
文摘The traditional Dead Reckoning algorithm predicts the future motion state based on a determined polynomial predictor,and the forecasting performance would vary with different types of motion entities.This paper proposes an enhanced dead reckoning algorithm based on hybrid extrapolation models,which can be used to reduce the communication in a distributed interactive simulation.The proposed algorithm perform extrapolation using a number of candidate predictors.Its idea is based on the assumption that a complex trajectory can be decomposed into several simple trajectories.The experimental evaluations show that the enhanced Dead Reckoning algorithm provides better performance in correction data reduction and accurate estimation.
