The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Lynn E Delisi - One of the best experts on this subject based on the ideXlab platform.
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abnormal interactions of verbal and spatial Memory networks in young people at familial high risk for schizophrenia
Schizophrenia Research, 2016Co-Authors: Heidi W Thermenos, Yoko Momura, Matcheri S Keshavan, Larry J Seidman, Lynn E DelisiAbstract:Abstract Background Working Memory impairment (especially in verbal and spatial domains) is the core neurocognitive impairment in schizophrenia and the familial high-risk (FHR) population. Inconsistent results have been reported in clinical and neuroimaging studies examining the verbal- and spatial-Memory deficits in the FHR subjects, due to sample differences and lack of understanding on interactions of the brain regions for processing verbal- and spatial-working Memory. Methods Functional MRI data acquired during a verbal- vs. spatial-Memory task were included from 51 young adults [26 FHR and 25 controls]. Group comparisons were conducted in brain activation patterns responding to 1) verbal-Memory Condition (A), 2) spatial-Memory Condition (B), 3) verbal higher than spatial (A–B), 4) spatial higher than verbal (B–A), 5) conjunction of brain regions that were activated during both A and B (A ∧ B). Group difference of the laterality index (LI) in inferior frontal lobe for Condition A was also assessed. Results Compared to controls, the FHR group exhibited significantly decreased brain activity in left inferior frontal during A, and significantly stronger involvement of ACC, PCC, paracentral gyrus for the contrast of A–B. The LI showed a trend of reduced left-higher-than-right pattern for verbal-Memory processing in the HR group. Conclusions Our findings suggest that in the entire functional brain network for working-Memory processing, verbal information processing associated brain pathways are significantly altered in people at familial high risk for developing schizophrenia. Future studies will need to examine whether these alterations may indicate vulnerability for predicting the onset of Schizophrenia.
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Abnormal interactions of verbal- and spatial-Memory networks in young people at familial high-risk for schizophrenia.
Schizophrenia research, 2016Co-Authors: Heidi W Thermenos, Yoko Momura, Matcheri Keshavan, Lawrence Seidman, Lynn E DelisiAbstract:Working Memory impairment (especially in verbal and spatial domains) is the core neurocognitive impairment in schizophrenia and the familial high-risk (FHR) population. Inconsistent results have been reported in clinical and neuroimaging studies examining the verbal- and spatial-Memory deficits in the FHR subjects, due to sample differences and lack of understanding on interactions of the brain regions for processing verbal- and spatial-working Memory. Functional MRI data acquired during a verbal- vs. spatial-Memory task were included from 51 young adults [26 FHR and 25 controls]. Group comparisons were conducted in brain activation patterns responding to 1) verbal-Memory Condition (A), 2) spatial-Memory Condition (B), 3) verbal higher than spatial (A-B), 4) spatial higher than verbal (B-A), 5) conjunction of brain regions that were activated during both A and B (A∧B). Group difference of the laterality index (LI) in inferior frontal lobe for Condition A was also assessed. Compared to controls, the FHR group exhibited significantly decreased brain activity in left inferior frontal during A, and significantly stronger involvement of ACC, PCC, paracentral gyrus for the contrast of A-B. The LI showed a trend of reduced left-higher-than-right pattern for verbal-Memory processing in the HR group. Our findings suggest that in the entire functional brain network for working-Memory processing, verbal information processing associated brain pathways are significantly altered in people at familial high risk for developing schizophrenia. Future studies will need to examine whether these alterations may indicate vulnerability for predicting the onset of Schizophrenia. Copyright © 2016 Elsevier B.V. All rights reserved.
Mauro Santos - One of the best experts on this subject based on the ideXlab platform.
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Asymptotic behavior to a von Kármán plate with boundary Memory Conditions
Nonlinear Analysis: Theory Methods & Applications, 2005Co-Authors: J.e. Muñoz Rivera, H. Portillo Oquendo, Mauro SantosAbstract:In this paper, we study the stability of solutions to a von Karman system for Kirchhoff plate equations with a Memory Condition working at the boundary. We show that such dissipation is strong enough to produce exponential decay of the solution provided the relaxation functions also decay exponentially. When the relaxation functions decay polynomially, we show that the solution decays polynomially.
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A boundary Condition with Memory for Kirchhoff plates equations
Applied Mathematics and Computation, 2004Co-Authors: Mauro Santos, F. JuniorAbstract:In this paper, we study the stability of solutions for Kirchhoff plates equations with a Memory Condition working at the boundary. We show that such dissipation is strong enough to produce exponential decay to the solution, provided the relaxation functions also decays exponentially. When the relaxation functions decays polynomially, we show that the solution decays polynomially and with the same rate.
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Global existence and stability for wave equation of Kirchhoff type with Memory Condition at the boundary
Nonlinear Analysis: Theory Methods & Applications, 2003Co-Authors: Mauro Santos, Jorge Ferreira, Ducival C. Pereira, Carlos A. RaposoAbstract:Abstract We consider a nonlinear wave equation of Kirchhoff type with Memory Condition at the boundary and we study the asymptotic behavior of the corresponding solutions. We proved that the energy decay with the same rate of decay of the relaxation function, that is, the energy decays exponentially when the relaxation function decay exponentially and polynomially when the relaxation function decay polynomially.
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decay rates for solutions of a timoshenko system with a Memory Condition at the boundary
Abstract and Applied Analysis, 2002Co-Authors: Mauro SantosAbstract:We consider a Timoshenko system with Memory Condition at the boundary and we study the asymptotic behavior of the corresponding solutions. We prove that the energy decay with the same rate of decay of the relaxation functions, that is, the energy decays exponentially when the relaxation functions decays exponentially and polynomially when the relaxation functions decays polynomially.
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asymptotic behavior of solutions to wave equations with a Memory Condition at the boundary
Electronic Journal of Differential Equations 2001 San Marcos Texas: Southwest Texas State University and University of North Texas., 2001Co-Authors: Mauro SantosAbstract:In this paper, we study the stability of solutions for wave equations whose boundary Condition includes a integral that represents the Memory eect. We show that the dissipation is strong enough to produce exponential decay of the solution, provided the relaxation function also decays exponentially. When the relaxation function decays polynomially, we show that the solution decays polynomially and with the same rate.
Jum-ran Kang - One of the best experts on this subject based on the ideXlab platform.
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General stability for a von Kármán plate system with Memory boundary Conditions
Boundary Value Problems, 2015Co-Authors: Jum-ran KangAbstract:In this paper we consider a von Karman plate system with Memory Condition at the boundary. We prove the asymptotic behavior of the corresponding solutions. We establish an explicit and general decay rate result using some properties of the convex functions. Our result is obtained without imposing any restrictive assumptions on the behavior of the relaxation function at infinity. These general decay estimates extend and improve on some earlier results-exponential or polynomial decay rates.
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General decay for a differential inclusion of Kirchhoff type with a Memory Condition at the boundary
Acta Mathematica Scientia, 2014Co-Authors: Jum-ran KangAbstract:Abstract In this article, we consider a differential inclusion of Kirchhoff type with a Memory Condition at the boundary. We prove the asymptotic behavior of the corresponding solutions. For a wider class of relaxation functions, we establish a more general decay result, from which the usual exponential and polynomial decay rates are only special cases.
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General Decay for the Degenerate Equation with a Memory Condition at the Boundary
Abstract and Applied Analysis, 2013Co-Authors: Su-young Shin, Jum-ran KangAbstract:We consider a degenerate equation with a Memory Condition at the boundary. For a wider class of relaxation functions, we establish a more general decay result, from which the usual exponential and polynomial decay rates are only special cases.
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General decay for Kirchhoff plates with a boundary Condition of Memory type
Boundary Value Problems, 2012Co-Authors: Jum-ran KangAbstract:In this paper we consider Kirchhoff plates with a Memory Condition at the boundary. For a wider class of relaxation functions, we establish a more general decay result, from which the usual exponential and polynomial decay rates are only special cases.
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existence uniqueness and uniform decay for the non linear degenerate equation with Memory Condition at the boundary
Applied Mathematics and Computation, 2008Co-Authors: Jong Yeoul Park, Jum-ran KangAbstract:This paper is concerned with the existence, uniqueness and uniform decay for the solution to the non-linear degenerate equation with Memory Condition at the boundary.
Sun Hye Park - One of the best experts on this subject based on the ideXlab platform.
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General decay of a von Karman plate equation with Memory on the boundary
Computers & Mathematics with Applications, 2018Co-Authors: Sun Hye ParkAbstract:Abstract We investigate the influence of boundary dissipation on the decay property of the solutions for a von Karman plate equation with a Memory Condition on one part of the boundary. Dropping the Condition u 0 = 0 on one part of the boundary, we show a general stability result for the equation via setting modified energy functionals which are equivalent to the energy of the equation and using some properties of convex functions. This result allows a wider class of relaxation functions and improve earlier results of Mustafa and Abusharkh (2015) and Park and Park (2005).
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Stability of a transmission problem for Kirchhoff-type wave equations with Memory on the boundary
Mathematical Methods in the Applied Sciences, 2016Co-Authors: Sun Hye ParkAbstract:In this paper, we investigate the influence of boundary dissipation on the decay property of solutions for a transmission problem of Kirchhoff-type wave equations with a Memory Condition on one part of the boundary. Without the Condition u0 = 0 on Γ0, we establish a general decay of energy depending on the behavior of relaxation function by introducing suitable energy and Lyapunov functionals. This result allows a wider class of relaxation functions. Copyright © 2016 John Wiley & Sons, Ltd.
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general decay of a transmission problem for kirchhoff type wave equations with boundary Memory Condition
Acta Mathematica Scientia, 2014Co-Authors: Sun Hye ParkAbstract:Abstract In this paper, we investigate the influence of boundary dissipation on the decay property of solutions for a transmission problem of Kirchhoff type wave equation with boundary Memory Condition. By introducing suitable energy and Lyapunov functionals, we establish a general decay estimate for the energy, which depends on the behavior of relaxation function.
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Adaptive stabilization of a von Karman plate equation with a boundary output feedback control
Computers & Mathematics with Applications, 2009Co-Authors: Jong Yeoul Park, Yong Han Kang, Sun Hye ParkAbstract:We consider a von Karman plate equation with boundary Memory Condition and output feedback control. We prove the existence of solutions using the Galerkin method and then investigate the stabilization of the corresponding solutions by choosing a suitable Lyapunov functional.
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uniform decay for a von karman plate equation with a boundary Memory Condition
Mathematical Methods in The Applied Sciences, 2005Co-Authors: Jong Yeoul Park, Sun Hye ParkAbstract:We consider a von Karman plate equation with a boundary Memory Condition. We prove the existence of solutions using the Galerkin method and then investigate the asymptotic behaviour of the corresponding solutions by choosing suitable Lyapunov functional. Copyright © 2005 John Wiley & Sons, Ltd.
Bryan J. Zolnikov - One of the best experts on this subject based on the ideXlab platform.
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Verbal and spatial working Memory performance among HIV-infected adults.
Journal of the International Neuropsychological Society : JINS, 2002Co-Authors: Charles H. Hinkin, David J. Hardy, Karen I. Mason, Steven A. Castellon, Mona N. Lam, M. Stefaniak, Bryan J. ZolnikovAbstract:Subtypes of working Memory performance were examined in a cohort of 50 HIV-infected adults and 23 uninfected controls using an n-back paradigm (2-back) in which alphabetic stimuli were quasi-randomly presented to a quadrant of a computer monitor. In the verbal working Memory Condition, participants determined whether each successive letter matched the letter that appeared two previously in the series, regardless of spatial location. In the spatial working Memory Condition, participants determined whether each letter matched the spatial location of the letter that had appeared two previously, regardless of letter identity. The dependent variable was percent accuracy in each Condition. Results of mixed model ANOVA revealed that the HIV-infected participants performed significantly worse than controls on both the verbal and spatial working Memory tasks. A significant main effect for working Memory Condition was also present with both participant groups performing better on the spatial working Memory task. These results, the first study of HIV-infected adults to directly compare verbal versus spatial working Memory performance using the identical test stimuli across task Conditions, suggests that HIV infection is associated with a decrement in working Memory efficiency that is equally apparent for both verbal and spatial processing. These findings implicate central executive dysfunction as a likely substrate and provide the basis for hypothesizing that decline in working Memory may contribute to other HIV-associated neuropsychological deficits. (JINS, 2002, 8, 532–538.)