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- Aaltonen, S, et al.
(författare)
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The Associations Between Leisure-Time Physical Activity and Academic Performance: A Twin Study
- 2021
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Ingår i: Journal of physical activity & health. - : Human Kinetics. - 1543-5474 .- 1543-3080. ; 18:8, s. 998-1003
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Tidskriftsartikel (refereegranskat)abstract
- Background: Both genetic and environmental influences have been shown to contribute to the association between physical activity and overall academic performance. The authors examined whether leisure-time physical activity (LTPA) shares genetic and environmental variances between spelling, essay writing, reading aloud, reading comprehension, and mathematics in early adolescence. Moreover, they investigated whether genetic polymorphisms associated with physical activity behavior affect these academic skills. Methods: Participants were 12-year-old Finnish twins (n = 4356–4370 twins/academic skill, 49% girls). Academic skills were assessed by teachers, and LTPA was self-reported. Polygenic scores for physical activity behavior were constructed from the UK Biobank. Quantitative genetic modeling and linear regression models were used to analyze the data. Results: The trait correlations between LTPA and academic skills were significant but weak (r = .05–.08). The highest trait correlation was found between LTPA and mathematics. A significant genetic correlation was revealed between LTPA and essay writing (rA = .14). Regarding polygenic scores of physical activity, the highest correlations were found with reading comprehension, spelling, and essay writing, but these results only approached statistical significance (P values = .09–.15). Conclusions: The authors’ results suggest that reading and writing are the academic skills that most likely share a common genetic background with LTPA.
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| 2. |
- Arvidsson, Björn, 1974-
(författare)
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Quantitative Bioanalysis : Liquid separations coupled to targeted mass spectrometric measurements of bioactive compounds
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Performing quantitative analysis of targeted bioactive compounds in biological samples, such as blood plasma, cerebrospinal fluid or extracts from pig liver, put high demands on the ruggedness of the method acquiring the results. In addition to the complexity of the sample matrix, the bioactive compounds targeted for analysis usually have low levels of natural abundance, further increasing the demand on the analytical method sensitivity. Furthermore, quantitation of analytes at trace levels in the presence of large amounts of interfering species in biofluids must aim for repeatable precision, high accuracy ensuring the closeness to the true values, a linear response spanning over several orders of magnitude and low limits of quantitation to be valid for monitoring disease states in clinical analysis.An analytical method most commonly follow a certain order of events, called the analytical chain, which includes; experimental planning, sampling, sample pre-treatment, separation of species, detection, evaluation, interpretation and validation, all equally important for the outcome of the results.In this thesis, the scope has been to create novel methods, or to refine already existing methods, in order to achieve even better performances of the different events in the analytical chain.One of the aspects has been to sample and enrich analytes in vivo by the use of solid supported microdialysis, giving the advantage of almost real-time monitoring of analyte levels within a living host with targeted selectivity due to the analyte affinity for solid particles. Another aspect to selectively clean and enrich analytes in a complex matrix has been developed and automated on-line by the use of a column-switching technique before the analytical separation. By using several steps of extraction and separation coupled on-line to selected detection by the use of a triple quadrupole mass spectrometer facilitates great selectivity of species. The mass spectrometer also gives the ability to distinguish between isotopically labelled analogues coeluting with the analytes yielding the necessary accuracy for quantitative evaluation.Both development of analytical methods and clinical applications has been performed, as well as improvements of existing techniques, all to improve the quantitation of trace levels of targeted analytes in biofluids.
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| 3. |
- Arvidsson, Daniel, 1974, et al.
(författare)
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Guide till metoder för att mäta fysisk aktivitet.
- 2016
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Ingår i: Idrottsmedicin. - 2001-3302. ; 16:3, s. 16-19
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Inom såväl forskning som klinik behöver man ofta uppskatta fysisk aktivitet på olika sätt. Det är viktigt att man använder rätt mätmetoder och är förtrogen med deras fördelar och begränsningar. Utvecklingen inom detta område går snabbt. Denna artikel är en kort guide över de vanligaste metoderna.
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| 8. |
- Baum, Christopher F., et al.
(författare)
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The Effects of Uncertainty on the Leverage of Non-Financial Firms
- 2009
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Ingår i: Economic Inquiry. - : John Wiley & Sons. - 0095-2583 .- 1465-7295. ; 47:2, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the link between the optimal level of nonfinancial firms’ short‐term leverage and macroeconomic and idiosyncratic sources of uncertainty. We develop a structural model of a firm’s value maximization problem that predicts a negative relationship between uncertainty and optimal levels of borrowing. This proposition is tested using a panel of nonfinancial U.S. firms drawn from the COMPUSTAT quarterly database covering the period 1993–2003. The estimates confirm that as either form of uncertainty increases, firms decrease their levels of short‐term leverage. This effect is stronger for macroeconomic uncertainty than for idiosyncratic uncertainty.
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| 9. |
- Beery, Thomas
(författare)
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Landscape Tourism
- 2023
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Konferensbidrag (populärvet., debatt m.m.)
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