2,903 research outputs found
Kadison-Kastler stable factors
A conjecture of Kadison and Kastler from 1972 asks whether sufficiently close operator algebras in a natural uniform sense must be small unitary perturbations of one another. For n≥3 and a free, ergodic, probability measure-preserving action of SL<sub>n</sub>(Z) on a standard nonatomic probability space (X,μ), write M=(L<sup>∞</sup>(X,μ)⋊SL<sub>n</sub>(Z))⊗¯¯¯R, where R is the hyperfinite II1-factor. We show that whenever M is represented as a von Neumann algebra on some Hilbert space H and N⊆B(H) is sufficiently close to M, then there is a unitary u on H close to the identity operator with uMu∗=N. This provides the first nonamenable class of von Neumann algebras satisfying Kadison and Kastler’s conjecture.
We also obtain stability results for crossed products L<sup>∞</sup>(X,μ)⋊Γ whenever the comparison map from the bounded to usual group cohomology vanishes in degree 2 for the module L<sup>2</sup>(X,μ). In this case, any von Neumann algebra sufficiently close to such a crossed product is necessarily isomorphic to it. In particular, this result applies when Γ is a free group
A remark on the similarity and perturbation problems
In this note we show that Kadison's similarity problem for C*-algebras is
equivalent to a problem in perturbation theory: must close C*-algebras have
close commutants?Comment: 6 Pages, minor typos fixed. C. R. Acad. Sci. Canada, to appea
Systemic inflammation alters the kinetics of cerebrovascular tight junction disruption after experimental stroke in mice
Systemic inflammatory stimulus potentiates the acute phase and CXC chemokine responses to experimental stroke and exacerbates brain damage via interleukin-1- and neutrophil-dependent mechanisms
Leading the evaluation of institutional online learning environments for quality enhancement in times of change
This paper reports on findings from a nationally funded project which aims to design and implement a quality management framework for online learning environments (OLEs). Evaluation is a key component of any quality management system and it is this aspect of the framework that is the focus of this paper. In developing the framework initial focus groups were conducted at the five participating institutions. These revealed that, although regarded as important, there did not appear to be a shared understanding of the nature and purpose of evaluation. A second series of focus groups revealed there were multiple perspectives arising from those with a vested interest in online learning. These perspectives will be outlined. Overall, how evaluation was undertaken was highly variable within and across the five institutions reflecting where they were at in relation to the development of their OLE
Modelling post-stroke depression : a systematic review and meta-analysis of animal studies.
Peer reviewedPreprin
Studies on inflammation and stroke provide clues to pathomechanism of central nervous system involvement in COVID-19
Occult Cerebrovascular Disease and Late-Onset Epilepsy: Could Loss of Neurovascular Unit Integrity Be a Viable Model?
Late-onset epilepsy (LOE) first occurs after 60 years of age and may be due to occult cerebrovascular disease (CVD) which confers an increased risk of stroke. However, patients with late-onset epilepsy are not currently consistently investigated or treated for cerebrovascular risk factors. We discuss how abnormalities of neurovascular unit
function, namely, changes in regional cerebral blood flow and blood brain barrier
disruption, may be caused by occult cerebrovascular disease but present clinically as
late-onset epilepsy. We describe novel magnetic resonance imaging methods to
detect abnormal neurovascular unit function in subjects with LOE and controls. We hypothesise that occult CVD may cause LOE as a result of neurovascular unit dysfunction
Therapeutic potential of extracellular vesicles in preclinical stroke models : a systematic review and meta-analysis
Funding: This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Prize Fellowship grant EP/N509565/1 and EPSRC and Medical Research Council (MRC) Centre for Doctoral Training in Regenerative Medicine studentship grant EP/L014904/1.Peer reviewedPublisher PD
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