Local equi-attraction of pullback attractor sections
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
Authors: Li, Fuzhi; Xin, Jie; Cui, Hongyong; Kloeden, Peter E.
Abstract
In this paper, we study a local equi-attraction of pullback attractors for nonautonomous processes. By the local equi-attraction we mean that any local part of sections of a pullback attractor U ={A(tau)}(tau is an element of R) are pullback attracting at the same rate, i.e., for any bounded (but arbitrarily large) interval I, lim(t ->infinity) (sup(tau is an element of I) dist(X)(U(t, tau - t, B), A(tau))) = 0, for all B subset of X bounded, where Xis a metric space and U: R+ x R x X -> Xis a process in X. Our technique makes use of the uniform attractor theory to consider in a dynamic way the time parameter tau involved in the pullback attractor. The analysis shows that, roughly, when a system has a uniform attractor, then the pullback attractor can be locally equi-attracting. As an example, the pullback attractor of 2D Navier-Stokes equation is studied, where the joint continuity in initial time and initial data of the solutions plays a key role. In addition, the continuity of the set-valued mapping tau -> A(tau) in more regular spaces is also studied. (C) 2020 Published by Elsevier Inc.
Functional genomic analyses uncover APOE-mediated regulation of brain and cerebrospinal fluid beta-amyloid levels in Parkinson disease
ACTA NEUROPATHOLOGICA COMMUNICATIONS
Authors: Ibanez, Laura; Bahena, Jorge A.; Yang, Chengran; Dube, Umber; Farias, Fabiana H. G.; Budde, John P.; Bergmann, Kristy; Brenner-Webster, Carol; Morris, John C.; Perrin, Richard J.; Cairns, Nigel J.; O'Donnell, John; alvarez, Ignacio; Diez-Fairen, Monica; Aguilar, Miquel; Miller, Rebecca; Davis, Albert A.; Pastor, Pau; Kotzbauer, Paul; Campbell, Meghan C.; Perlmutter, Joel S.; Rhinn, Herve; Harari, Oscar; Cruchaga, Carlos; Benitez, Bruno A.
Abstract
Alpha-synuclein is the main protein component of Lewy bodies, the pathological hallmark of Parkinson's disease. However, genetic modifiers of cerebrospinal fluid (CSF) alpha-synuclein levels remain unknown. The use of CSF levels of amyloid beta(1-42), total tau, and phosphorylated tau(181) as quantitative traits in genetic studies have provided novel insights into Alzheimer's disease pathophysiology. A systematic study of the genomic architecture of CSF biomarkers in Parkinson's disease has not yet been conducted. Here, genome-wide association studies of CSF biomarker levels in a cohort of individuals with Parkinson's disease and controls (N = 1960) were performed. PD cases exhibited significantly lower CSF biomarker levels compared to controls. A SNP, proxy for APOE epsilon 4, was associated with CSF amyloid beta(1-42) levels (effect = - 0.5, p = 9.2 x 10(-19)). No genome-wide loci associated with CSF alpha-synuclein, total tau, or phosphorylated tau(181) levels were identified in PD cohorts. Polygenic risk score constructed using the latest Parkinson's disease risk meta-analysis were associated with Parkinson's disease status (p = 0.035) and the genomic architecture of CSF amyloid beta(1-42) (R-2 = 2.29%; p = 2.5 x 10(-11)). Individuals with higher polygenic risk scores for PD risk presented with lower CSF amyloid beta(1-42) levels (p = 7.3 x 10(-04)). Two-sample Mendelian Randomization revealed that CSF amyloid beta(1-42) plays a role in Parkinson's disease (p = 1.4 x 10(-05)) and age at onset (p = 7.6 x 10(-06)), an effect mainly mediated by variants in the APOE locus. In a subset of PD samples, the APOE epsilon 4 allele was associated with significantly lower levels of CSF amyloid beta(1-42) (p = 3.8 x 10(-06)), higher mean cortical binding potentials (p = 5.8 x 10(-08)), and higher Braak amyloid beta score (p = 4.4 x 10(-04)). Together these results from high-throughput and hypothesis-free approaches converge on a genetic link between Parkinson's disease, CSF amyloid beta(1-42), and APOE.