| 1. |
- Abdellah, Tebani, et al.
(författare)
-
Integration of molecular profiles in a longitudinal wellness profiling cohort.
- 2020
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- An important aspect of precision medicine is to probe the stability in molecular profiles among healthy individuals over time. Here, we sample a longitudinal wellness cohort with 100 healthy individuals and analyze blood molecular profiles including proteomics, transcriptomics, lipidomics, metabolomics, autoantibodies and immune cell profiling, complemented with gut microbiota composition and routine clinical chemistry. Overall, our results show high variation between individuals across different molecular readouts, while the intra-individual baseline variation is low. The analyses show that each individual has a unique and stable plasma protein profile throughout the study period and that many individuals also show distinct profiles with regards to the other omics datasets, with strong underlying connections between the blood proteome and the clinical chemistry parameters. In conclusion, the results support an individual-based definition of health and show that comprehensive omics profiling in a longitudinal manner is a path forward for precision medicine.
|
|
| 2. |
- Ghisletta, Paolo, et al.
(författare)
-
On the use of growth models to study normal cognitive aging
- 2020
-
Ingår i: International Journal of Behavioral Development. - : SAGE Publications. - 0165-0254 .- 1464-0651. ; 44:1, s. 88-96
-
Tidskriftsartikel (refereegranskat)abstract
- Growth models (GM) of the mixed-effects and latent curve varieties have become popular methodological tools in lifespan research. One of the major advantages of GM is their flexibility in studying individual differences in change. We scrutinized the change functions of GM used in five years of publications on cognitive aging. Of the 162 publications that we identified, 88% test linear or quadratic polynomials, and fewer than 5% apply functions that are nonlinear in their parameters, such as exponential decline. This apparent bias in favor of polynomial decomposition calls for exploring what conclusions about individual differences in change are likely to be drawn if one applies linear or quadratic GMs to data simulated under a conceptually and empirically plausible model of exponential cognitive decline from adulthood to old age. Hence, we set up a simulation that manipulated the rate of exponential decline, measurement reliability, number of occasions, interval width, and sample size. True rate of decline and interval width influenced results strongly, number of occasions and measurement reliability exerted a moderate effect, and the effects of sample size appeared relatively minor. Critically, our results show that fit statistics generally do not differentiate misspecified linear or quadratic models from the true exponential model. Moreover, power to detect variance in change for the linear and quadratic GMs is low, and estimates of individual differences in level and change can be highly biased by model misspecification. We encourage researchers to also consider plausible nonlinear change functions when studying behavioral development across the lifespan.
|
|
| 3. |
- Schillings, Audrey, et al.
(författare)
-
Earth’s O+ Outflow and Escape during Various Solar Wind Conditions
- 2020
-
Konferensbidrag (refereegranskat)abstract
- Ion outflow at Earth is studied since several decades and is important for the global atmospheric evolution. Over the years, spacecraft and technology improved leading to new studies and breakthrough in the field. With different mechanisms to gain energy and velocity such as field-aligned acceleration, centrifugal acceleration and transversal heating, a large amount of ions becomes gravitationally untrapped above the ionosphere. While some of these ions may enter the plasma sheet and partially be redirected towards Earth, majority of these ions reaches the high-latitude boundary region, such as the plasma mantle and are lost into the solar wind. We examined this phenomenon using Cluster European Spacecraft that covers these high-latitude regions. Here, we studied the influence of solar wind conditions on O+ outflow and escape during 7 years of observations (2001 to 2007). We found that O+ outflow is exponentially correlated with enhanced geomagnetic activity (Kp index) as well as with solar wind dynamic pressure and IMF. Under undisturbed magnetospheric conditions, the O+ outflow is typically 1012.5 m-2s-1 while it reaches 1014 m-2s-1 during major geomagnetic storms. Additionally, tracing (forward in time) about 25000 O+ ions initially observed in the plasma mantle showed that 98% of these ions escape directly through the magnetopause whereas only a few escape through the distant tail. In summary, the more disturbed the magnetosphere is, the more ion outflow and escape is observed.
|
|
| 4. |
- Schillings, Audrey, et al.
(författare)
-
The fate of O+ ions observed in the plasma mantle : particle tracing modelling and Cluster observations
- 2020
-
Konferensbidrag (refereegranskat)abstract
- The atmospheric evolution on geological timescales is partly given by the atmospheric escape. This escape includes ion escape and particularly O+ ions. How much O+ ions escape from the Earth is the main focus of this study. Using the Tsyganenko and Weimer models to represent the magnetic and electric fields respectively, we traced 26200 O+ ions trajectories forward in time and studied their final positions in the Earth’s environment. Starting in the plasma mantle, the initial positions, thermal and parallel bulk velocities of O+ ions are taken from the European Cluster observations between 2001 and 2007. Most (98%) of the ions observed in the plasma mantle escape the Earth’s magnetosphere, with 20% of them directly through the dayside magnetopause. An interesting feature of the 80% escaping ions left is that very few reach the distant tail, they rather escape through the nightside magnetopause. Finally, no significant correlation was found between magnetospheric disturbed conditions and the final positions of the traced O+ ions.
|
|
| 5. |
- Schillings, Audrey, et al.
(författare)
-
The fate of O+ ions observed in the plasma mantle: particle tracing modelling and cluster observations
- 2020
-
Ingår i: Annales Geophysicae. - : Copernicus Publications. - 0992-7689 .- 1432-0576. ; 38:3, s. 645-656
-
Tidskriftsartikel (refereegranskat)abstract
- Ion escape is of particular interest for studying the evolution of the atmosphere on geological timescales. Previously, using Cluster-CODIF data, we investigated the oxygen ion outflow from the plasma mantle for different solar wind conditions and geomagnetic activity. We found significant correlations between solar wind parameters, geomagnetic activity (Kp index), and the O+ outflow. From these studies, we suggested that O+ ions observed in the plasma mantle and cusp have enough energy and velocity to escape the magnetosphere and be lost into the solar wind or in the distant magnetotail. Thus, this study aims to investigate where the ions observed in the plasma mantle end up. In order to answer this question, we numerically calculate the trajectories of O+ ions using a tracing code to further test this assumption and determine the fate of the observed ions. Our code consists of a magnetic field model (Tsyganenko T96) and an ionospheric potential model (Weimer 2001) in which particles initiated in the plasma mantle region are launched and traced forward in time. We analysed 131 observations of plasma mantle events in Cluster data between 2001 and 2007, and for each event 200 O+ particles were launched with an initial thermal and parallel bulk velocity corresponding to the velocities observed by Cluster. After the tracing, we found that 98 % of the particles are lost into the solar wind or in the distant tail. Out of these 98 %, 20 % escape via the dayside magnetosphere.
|
|
