| 1. |
- Oyama, Shin-ichiro, et al.
(författare)
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Auroral molecular-emission effects on the atomic oxygen line at 777.4 nm
- 2018
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Ingår i: Earth Planets and Space. - : SPRINGEROPEN. - 1343-8832 .- 1880-5981. ; 70
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Tidskriftsartikel (refereegranskat)abstract
- One of the representative auroral emission lines that radiates from F-region heights and is measurable on the ground is the 777.4nm line from excited atomic oxygen. This line has been adopted, along with another E-region emission line, for example 427.8nm, to estimate the mean energy and total energy flux of precipitating auroral electrons. The influence of emissions from part of the molecular nitrogen band, which mainly radiate from E-region heights, should be carefully evaluated because it might overlap the 777.4nm atomic oxygen line in the spectrum. We performed statistical analysis of auroral spectrograph measurements that were obtained during the winter of 2016-2017 in TromsO, Norway, to derive the ratio of the intensity of the 777.4nm atomic oxygen line to that of the net measurement through a typically used optical filter with a full width at half maximum of a few nm. The ratio had a negative trend against geomagnetic activity, with a primary distribution of 0.5-0.7 and a minimum value of 0.3 for the most active auroral condition in this study. This result suggests that the 30-50% emission intensities measured through the optical filter may be from the molecular nitrogen band.
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| 2. |
- Pitout, Frédéric, 1972-
(författare)
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The Polar Cusp and its Ionospheric footprint : Dynamics and Transients
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The magnetopause, the boundary layer between the solar wind and the Earth’s magnetosphere, is not closed as we have long thought. Transfers of energy, particles and momentum from the solar wind to the magnetosphere actually take place. In the Earth’s magnetosphere, the polar cusps are two key regions where the solar wind particles have direct access to the magnetosphere and the polar ionosphere. The ionospheric footprint of the polar cusp is highly dynamic because its location and behavior depend directly on the external conditions (interplanetary magnetic field and solar wind pressure). The cusp dynamics has been studied by means of ground-based and satellite-borne instrumentation. The theory of magnetic reconnection has been successful in explaining entry of solar wind particles into the magnetosphere. Observations indicate that the reconnection process is not steady but rather sporadic or pulsed. The consequences of transient injections of solar wind particles into the dayside high-latitude ionosphere and the associated strong convection electric fields are observed, modeled and discussed.
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| 3. |
- Sakamoto, Kenichi, et al.
(författare)
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R3hdml regulates satellite cell proliferation and differentiation
- 2019
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Ingår i: EMBO Reports. - : John Wiley & Sons. - 1469-221X .- 1469-3178. ; 20:11
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we identified a previously uncharacterized skeletal satellite cell-secreted protein, R3h domain containing-like (R3hdml). Expression of R3hdml increases during skeletal muscle development and differentiation in mice. Body weight and skeletal muscle mass of R3hdml knockout (KO) mice are lower compared to control mice. Expression levels of cell cycle-related markers, phosphorylation of Akt, and expression of insulin-like growth factor within the skeletal muscle are reduced in R3hdml KO mice compared to control mice. Expression of R3hdml increases during muscle regeneration in response to cardiotoxin (CTX)-induced muscle injury. Recovery of handgrip strength after CTX injection was significantly impaired in R3hdml KO mice, which is rescued by R3hdml. Our results indicate that R3hdml is required for skeletal muscle development, regeneration, and, in particular, satellite cell proliferation and differentiation.
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