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- Fjell, Anders M., et al.
(författare)
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Poor Self-Reported Sleep is Related to Regional Cortical Thinning in Aging but not Memory Decline-Results From the Lifebrain Consortium
- 2021
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 31:4, s. 1953-1969
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether sleep quality and quantity are associated with cortical and memory changes in cognitively healthy participants across the adult lifespan. Associations between self-reported sleep parameters (Pittsburgh Sleep Quality Index, PSQI) and longitudinal cortical change were tested using five samples from the Lifebrain consortium (n = 2205, 4363 MRIs, 18-92 years). In additional analyses, we tested coherence with cell-specific gene expression maps from the Allen Human Brain Atlas, and relations to changes in memory performance. "PSQI # 1 Subjective sleep quality" and "PSQI #5 Sleep disturbances" were related to thinning of the right lateral temporal cortex, with lower quality and more disturbances being associated with faster thinning. The association with "PSQI #5 Sleep disturbances" emerged after 60 years, especially in regions with high expression of genes related to oligodendrocytes and S1 pyramidal neurons. None of the sleep scales were related to a longitudinal change in episodic memory function, suggesting that sleep-related cortical changes were independent of cognitive decline. The relationship to cortical brain change suggests that self-reported sleep parameters are relevant in lifespan studies, but small effect sizes indicate that self-reported sleep is not a good biomarker of general cortical degeneration in healthy older adults.
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- García-Lisbona, Juan Gracia, et al.
(författare)
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FASTER: Reaction wheel stabilized platform to improve microgravity conditions for experiments in parabolic flights
- 2021
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Ingår i: IAC 2021 Congress Proceedings, 72nd International Astronautical Congress (IAC), Dubai, United Arab Emirates. - : International Astronautical Federation, IAF.
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Konferensbidrag (refereegranskat)abstract
- Parabolic flights are widely used for conducting experiments in microgravity and practising for satellite missions or for human space flights. Testing an experiment, a piece of equipment or a spacecraft system in low gravity conditions is often required before it can be included in a space mission. Most often, parabolic flights are performed on large aircraft such as ESA’s Airbus A310 ZERO-G. They offer relatively long periods of low gravity per flight and plenty of space for experiment setup. However, the use of large aircraft also results in higher cost, low repeatability, and constraints in location as the flights need to be performed from large airfields. This is one reason for the growing interest in parabolic flights using smaller aircraft, gliders or Unmanned Aerial Vehicles (UAVs). They offer lower initial and operational costs, shorter waiting times and higher flexibility regarding the location where the flight is performed. Depending on the experiment, these advantages will be more important than related challenges of short durations of parabolas and limited space inside the aircraft. The microgravity conditions provided by large planes, 10-2 - 10-3 g, are not as good as those achieved at other microgravity platforms such as drop towers, sounding rockets, or the International Space Station (ISS). With smaller aircraft, the quality could be even lower, 10-1 - 10-2 g, due to their increased sensitivity to perturbations such as oscillations and vibrations. Regardless of which of these two platforms will be used, the low-gravity conditions could be improved by reducing the effect of external disturbances and by increasing the stability. The main objectives of project FASTER (Flying Attitude STabilized ExpeRiment) are to build a stabilizing platform and to prove that it can improve the microgravity conditions for payload experiments during parabolic flights. The Attitude Control System (ACS) uses three reaction wheels, and it is based on the ASTER on REXUS experiment that will be ejected from a sounding rocket during the upcoming 30th ESA Rexus campaign. The platform will be tested in 2021 on the first student Arctic parabolic flight campaign organized in Kiruna, Sweden, using a light Cessna aircraft.
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- Roe, James M., et al.
(författare)
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Asymmetric thinning of the cerebral cortex across the adult lifespan is accelerated in Alzheimer’s disease
- 2021
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Aging and Alzheimer’s disease (AD) are associated with progressive brain disorganization. Although structural asymmetry is an organizing feature of the cerebral cortex it is unknown whether continuous age- and AD-related cortical degradation alters cortical asymmetry. Here, in multiple longitudinal adult lifespan cohorts we show that higher-order cortical regions exhibiting pronounced asymmetry at age ~20 also show progressive asymmetry-loss across the adult lifespan. Hence, accelerated thinning of the (previously) thicker homotopic hemisphere is a feature of aging. This organizational principle showed high consistency across cohorts in the Lifebrain consortium, and both the topological patterns and temporal dynamics of asymmetry-loss were markedly similar across replicating samples. Asymmetry-change was further accelerated in AD. Results suggest a system-wide dedifferentiation of the adaptive asymmetric organization of heteromodal cortex in aging and AD.
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- Vidal-Pineiro, Didac, et al.
(författare)
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Individual variations in 'brain age' relate to early-life factors more than to longitudinal brain change
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Brain age is a widely used index for quantifying individuals’ brain health as deviation from a normative brain aging trajectory. Higher-than-expected brain age is thought partially to reflect above-average rate of brain aging. Here, we explicitly tested this assumption in two indepen-dent large test datasets (UK Biobank [main] and Lifebrain [replication]; longitudinal observations ≈ 2750 and 4200) by assessing the relationship between cross-sectional and longitudinal estimates of brain age. Brain age models were estimated in two different training datasets (n ≈ 38,000 [main] and 1800 individuals [replication]) based on brain structural features. The results showed no association between cross-sectional brain age and the rate of brain change measured longitudinally. Rather, brain age in adulthood was associated with the congenital factors of birth weight and polygenic scores of brain age, assumed to reflect a constant, lifelong influence on brain structure from early life. The results call for nuanced interpretations of cross-sectional indices of the aging brain and question their validity as markers of ongoing within-person changes of the aging brain. Longitudinal imaging data should be preferred whenever the goal is to understand individual change trajectories of brain and cognition in aging.
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- Weyns, Danny, et al.
(författare)
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The vision of self-evolving computing systems
- 2023
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Ingår i: Journal of Integrated Design & Process Science. - : IOS Press. - 1092-0617 .- 1875-8959. ; 26:3-4, s. 351-367
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Tidskriftsartikel (refereegranskat)abstract
- Computing systems are omnipresent; their sustainability has become crucial for our society. A key aspect of this sustainability is the ability of computing systems to cope with the continuous change they face, ranging from dynamic operating conditions, to changing goals, and technological progress. While we are able to engineer smart computing systems that autonomously deal with various types of changes, handling unanticipated changes requires system evolution, which remains in essence a human-centered process. This will eventually become unmanageable. To break through the status quo, we put forward an arguable opinion for the vision of self-evolving computing systems that are equipped with an evolutionary engine enabling them to evolve autonomously. Specifically, when a self-evolving computing systems detects conditions outside its operational domain, such as an anomaly or a new goal, it activates an evolutionary engine that runs online experiments to determine how the system needs to evolve to deal with the changes, thereby evolving its architecture. During this process the engine can integrate new computing elements that are provided by computing warehouses. These computing elements provide specifications and procedures enabling their automatic integration. We motivate the need for self-evolving computing systems in light of the state of the art, outline a conceptual architecture of self-evolving computing systems, and illustrate the architecture for a future smart city mobility system that needs to evolve continuously with changing conditions. To conclude, we highlight key research challenges to realize the vision of self-evolving computing systems.
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