| 1. |
- Webster, Christopher R., et al.
(författare)
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Background levels of methane in Mars' atmosphere show strong seasonal variations
- 2018
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 360:6393, s. 1093-1096
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Tidskriftsartikel (refereegranskat)abstract
- Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.
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| 2. |
- Gómez, M. J., et al.
(författare)
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Analysis of Vibration Signals of Drivetrain Failures in Wind Turbines for Condition Monitoring
- 2021
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Ingår i: Experimental techniques (Westport, Conn.). - : Springer. - 0732-8818 .- 1747-1567. ; 45:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- In the last years, the wind industry has increased in a large scale. A wind turbine out of service leeds to high costs due to both maintenance and repair costs and the incapability of producing electricity. A substantial part of the wind turbine failures are in the drivetrain, mainly in generator and gearbox. Several recent works focuses in the study of benefits of the integration of condition monitoring with current maintenance techniques, that would drive to the reduction of costs. For condition monitoring, vibration analysis has been widely accepted as the technique that gives most information about faults in a rotating machine, thus vibration sensors are often used in wind turbine applications. In this work, data from several vibration sensors installed in 18 wind turbines in cold climate were analysed using the Wavelet Packets Transform energy. Signals were acquired for more than four years (from 2011 to 2015), registering failures in gearboxes and generators of the wind turbines. Data were obtained under varying conditions of load and speed as well as varying weather conditions. Signals were analysed with the aim of finding parameters that indicate the presence of a fault. This would be useful to predict a failure with enough time to plan a stop of the wind turbine in the proper moment for similar faults in the future.
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| 3. |
- Skjaerven, Liv Helvik, et al.
(författare)
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A vocabulary describing health-terms of movement quality : a phenomenological study of movement communication
- 2020
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Ingår i: Disability and Rehabilitation. - : Taylor & Francis. - 0963-8288 .- 1464-5165. ; 42:22, s. 3152-3161
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of the study was to develop a vocabulary targeting communication of health-terms ofmovement quality, establishing professional knowledge of a movement terminology usefull withinrehabilitation.Methods: A phenomenological study design was chosen, inviting movement experts working inrehabilitation to describe movement observations when a change into more functional, health relatedways of moving appeared in the rehabilitation processes. 15 physiotherapy experts were recruited,five from the field of neurology, primary health care and psychiatry. The informants had between12-38 years of clinical practice, treating patients of all ages with a wide specter of diagnoses. Datacollection followed a qualitative study design, of individual, in-depth interviews, based on a semi-structured interview guide. The interviews were taped, transcribed and sent to the informants forvalidation. Data analysis followed recommendation of Giorgi, modified by Malterud. Ethical considera-tions were followed.Results: Data revealed a vocabulary, clustered in five themes, Biomechanical, Physiological, Psycho-socio-cultural, Existential and Overarching perspective, 16 underlying categories and 122 descriptive health-terms of movement quality.Conclusion: The study demonstrated a multi-perspective movement vocabulary of 122 health characteris-tic terms, developed to facilitate movement communication within the broad field of rehabilitation. Theresult calls for further research concerning a movement vocabulary.
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| 4. |
- Yaghootkar, Hanieh, et al.
(författare)
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Genetic Studies of Leptin Concentrations Implicate Leptin in the Regulation of Early Adiposity
- 2020
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 69:12, s. 2806-2818
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Tidskriftsartikel (refereegranskat)abstract
- Leptin influences food intake by informing the brain about the status of body fat stores. Rare LEP mutations associated with congenital leptin deficiency cause severe early-onset obesity that can be mitigated by administering leptin. However, the role of genetic regulation of leptin in polygenic obesity remains poorly understood. We performed an exome-based analysis in up to 57,232 individuals of diverse ancestries to identify genetic variants that influence adiposity-adjusted leptin concentrations. We identify five novel variants, including four missense variants, in LEP, ZNF800, KLHL31, and ACTL9, and one intergenic variant near KLF14. The missense variant Val94Met (rs17151919) in LEP was common in individuals of African ancestry only, and its association with lower leptin concentrations was specific to this ancestry (P = 2 × 10-16, n = 3,901). Using in vitro analyses, we show that the Met94 allele decreases leptin secretion. We also show that the Met94 allele is associated with higher BMI in young African-ancestry children but not in adults, suggesting that leptin regulates early adiposity.
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