| 1. |
- Andreasson, Håkan, 1966, et al.
(author)
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Proof of the cosmic no-hair conjecture in the T-3-Gowdy symmetric Einstein-Vlasov setting
- 2016
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In: Journal of the European Mathematical Society. - : European Mathematical Society - EMS - Publishing House GmbH. - 1435-9863 .- 1435-9855. ; 18:7, s. 1565-1650
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Journal article (peer-reviewed)abstract
- The currently preferred models of the universe undergo accelerated expansion induced by dark energy. One model for dark energy is a positive cosmological constant. It is consequently of interest to study Einstein's equations with a positive cosmological constant coupled to matter satisfying the ordinary energy conditions: the dominant energy condition etc. Due to the difficulty of analysing the behaviour of solutions to Einstein's equations in general, it is common to either study situations with symmetry, or to prove stability results. In the present paper, we do both. In fact, we analyse, in detail, the future asymptotic behaviour of T-3-Gowdy symmetric solutions to the Einstein-Vlasov equations with a positive cosmological constant. In particular, we prove the cosmic no-hair conjecture in this setting. However, we also prove that the solutions are future stable (in the class of all solutions). Some of the results hold in a more general setting. In fact, we obtain conclusions concerning the causal structure of T-2-symmetric solutions, assuming only the presence of a positive cosmological constant, matter satisfying various energy conditions and future global existence. Adding the assumption of T-3-Gowdy symmetry to this list of requirements, we obtain C-0-estimates for all but one of the metric components. There is consequently reason to expect that many of the results presented in this paper can be generalised to other types of matter.
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| 2. |
- Nielsen, Niels Peter, et al.
(author)
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Associations between AQT processing speed and neuropsychological tests in neuropsychiatric patients
- 2007
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In: American Journal of Alzheimers Disease & other Dementias. - : SAGE Publications. - 1938-2731 .- 1533-3175. ; 22:3, s. 202-210
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Journal article (peer-reviewed)abstract
- Associations between A Quick Test of Cognitive Speed (AQT) perceptual and cognitive speed and neuropsychological tests, including the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III), Mini Mental State Examination (MMSE), and the Trail Making Test (TMT), were evaluated in 41 neuropsychiatric patients. Neuropsychological and neurological tests, including CT scan, were administered to all of the patients. AQT was also administered to 75 controls. All AQT means differed significantly for patients and controls. Dual-dimension naming time means in the patient group were in the atypical range and indicated generally reduced cognitive speed, whereas controls performed in the normal range. In the patient group, WAIS-III verbal, performance, and full-scale IQ means were in the normal range. AQT perceptual and cognitive speed correlated negatively with WAIS-III P IQ and MMSE scores, and the relationships were nonlinear. The findings support that AQT dual-dimension naming evaluates cognitive speed (i.e., attention, set shifting, working memory) and can be used for first-line or complementary screening for mild or progressive cognitive impairments.
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