| 1. |
- Botvinik-Nezer, Rotem, et al.
(författare)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 2. |
- Shahnawaz, Mohammad, et al.
(författare)
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Discriminating alpha-synuclein strains in Parkinsons disease and multiple system atrophy
- 2020
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Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 578:7794, s. 273-277
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Tidskriftsartikel (refereegranskat)abstract
- Synucleinopathies are neurodegenerative diseases that are associated with the misfolding and aggregation of alpha-synuclein, including Parkinsons disease, dementia with Lewy bodies and multiple system atrophy(1). Clinically, it is challenging to differentiate Parkinsons disease and multiple system atrophy, especially at the early stages of disease(2). Aggregates of alpha-synuclein in distinct synucleinopathies have been proposed to represent different conformational strains of alpha-synuclein that can self-propagate and spread from cell to cell(3-6). Protein misfolding cyclic amplification (PMCA) is a technique that has previously been used to detect alpha-synuclein aggregates in samples of cerebrospinal fluid with high sensitivity and specificity(7,8). Here we show that the alpha-synuclein-PMCA assay can discriminate between samples of cerebrospinal fluid from patients diagnosed with Parkinsons disease and samples from patients with multiple system atrophy, with an overall sensitivity of 95.4%. We used a combination of biochemical, biophysical and biological methods to analyse the product of alpha-synuclein-PMCA, and found that the characteristics of the alpha-synuclein aggregates in the cerebrospinal fluid could be used to readily distinguish between Parkinsons disease and multiple system atrophy. We also found that the properties of aggregates that were amplified from the cerebrospinal fluid were similar to those of aggregates that were amplified from the brain. These findings suggest that alpha-synuclein aggregates that are associated with Parkinsons disease and multiple system atrophy correspond to different conformational strains of alpha-synuclein, which can be amplified and detected by alpha-synuclein-PMCA. Our results may help to improve our understanding of the mechanism of alpha-synuclein misfolding and the structures of the aggregates that are implicated in different synucleinopathies, and may also enable the development of a biochemical assay to discriminate between Parkinsons disease and multiple system atrophy. Protein misfolding cyclic amplification (PMCA) technology can discriminate between patients with Parkinsons disease and patients with multiple system atrophy on the basis of the characteristics of the alpha-synuclein aggregates in the cerebrospinal fluid.
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| 3. |
- Soltesz, Kristian, et al.
(författare)
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The effect of interventions on COVID-19
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 588:7839, s. 26-28
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Tidskriftsartikel (refereegranskat)
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