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- Armengaud, E., et al.
(author)
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Physics potential of the International Axion Observatory (IAXO)
- 2019
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In: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
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Journal article (peer-reviewed)abstract
- We review the physics potential of a next generation search for solar axions: the International Axion Observatory (IAXO). Endowed with a sensitivity to discover axion-like particles (ALPs) with a coupling to photons as small as g(a gamma) similar to 10(-12) GeV-1, or to electrons g(ae) similar to 10(-13), IAXO has the potential to find the QCD axion in the 1 meV similar to 1 eV mass range where it solves the strong CP problem, can account for the cold dark matter of the Universe and be responsible for the anomalous cooling observed in a number of stellar systems. At the same time, IAXO will have enough sensitivity to detect lower mass axions invoked to explain: 1) the origin of the anomalous transparency of the Universe to gamma-rays, 2) the observed soft X-ray excess from galaxy clusters or 3) some inflationary models. In addition, we review string theory axions with parameters accessible by IAXO and discuss their potential role in cosmology as Dark Matter and Dark Radiation as well as their connections to the above mentioned conundrums.
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| 2. |
- Peace, Alexander L., et al.
(author)
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Evidence for Basement Reactivation during the Opening of the Labrador Sea from the Makkovik Province, Labrador, Canada : Insights from Field Data and Numerical Models
- 2018
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In: Geosciences. - : MDPI. - 2076-3263. ; 8:8
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Journal article (peer-reviewed)abstract
- The onshore exposures adjacent to modern, offshore passive continental margins may preserve evidence of deformation from the pre-, syn-, and post-rift phases of continental breakup that allow us to investigate the processes associated with and controlling rifting and breakup. Here, we characterize onshore brittle deformation and pre-rift basement metamorphic mineral fabric from onshore Labrador in Eastern Canada in the Palaeoproterozoic Aillik Domain of the Makkovik Province. Stress inversion (1) was applied to these data and then compared to (2) numerical models of hybrid slip and dilation tendency, (3) independent calculations of the regional geopotential stress field, and (4) analyses of palaeo-stress in proximal regions from previous work. The stress inversion shows well-constrained extensional deformation perpendicular to the passive margin, likely related to pre-breakup rifting in the proto-Labrador Sea. Hybrid slip and dilatation analysis indicates that inherited basement structures were likely oriented in a favorable orientation to be reactivated during rifting. Reconstructed geopotential stresses illuminate changes of the ambient stress field over time and confirm the present paleo-stress estimates. The new results and numerical models provide a consistent picture of the late Mesozoic-Cenozoic lithospheric stress field evolution in the Labrador Sea region. The proto-Labrador Sea region was characterized by a persistent E-W (coast-perpendicular) extensional stress regime, which we interpret as the pre-breakup continental rifting that finally led to continental breakup. Later, the ridge push of the Labrador Sea spreading ridge maintained this general direction of extension. We see indications for anti-clockwise rotation of the direction of extension along some of the passive margins. However, extreme persistent N-S-oriented extension as indicated by studies further north in West Greenland cannot be confirmed.
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| 4. |
- Zinner, Christoph, et al.
(author)
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Sprint interval training or arms and legs elevates peak VO2 and improves arm exercise economy
- 2015
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Conference paper (peer-reviewed)abstract
- IntroductionInterval cycle sprint training (SIT) has been shown to improve anaerobic capacity, VO2max and biomarkers of muscle oxidative capacity in as little as 2 weeks in previously untrained adults. The present study was designed to characterize and compare systemic VO2 and exercise performance after SIT engaging the arms and legs. MethodsSixteen healthy, untrained men (23.9 ± 3.7 yrs; 183.8 ± 6.8 cm; 80.3 ± 14.1 kg) performed six sessions of 4-6x30 sec all-out sprints with the legs then arms (or vice versa) separated by a 1-h recovery over an 11-day period. Limb-specific VO2peak, anaerobic capacity (2x30-sec Wingate tests with 4 min of recovery), a 4-min submaximal work economy test, and a 5-min all-out time trial (TT) were conducted before and after the training program. Muscle biopsies (from the m. vastus lateralis and m. triceps brachii) were taken before and after the training period. ResultsVO2peak increased by 10.6% and 5.9% with arm and leg training, respectively (p<0.05), with the increase in the arms significantly greater than in the legs (p=0.02). Work economy was improved for the arms (-9.8%, p<0.05), but not for the legs (-0.9%). Mean power during the TT rose by 13.5% for the arms and 11.8% for the legs (p<0.05). Peak power output and mean power during the two Wingate tests were elevated in both the arms (PPO: 6.7% (p<0.01) and 13.3% (p<0.01); MPO: 6.1% (p<0.01) and 8.4% (p<0.01)) and legs (PPO: 3.1% (p=0.07) and 7.1% (p=0.02); MPO: 3.3% (p<0.01) and 5.6% (p<0.01)). The activity of 3-hydroxyacyl-CoA dehydrogenase (HAD) and levels of muscle glycogen were unchanged in both limbs. DiscussionSprint interval training with arm or leg cycling exercise increased peak pulmonary VO2 during their respective modes over an 11-day training period with a greater increase in the arms. Sprint performance rose to a similar extent in both extremities, yet work economy was improved only in the arms. These findings suggest some limb-specific responsiveness to SIT training.
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