| 1. |
- Obers, Niels A., et al.
(författare)
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Quantum gravity phenomenology at the dawn of the multi-messenger era—A review
- 2022
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Ingår i: Progress in Particle and Nuclear Physics. - : Elsevier BV. - 0146-6410 .- 1873-2224. ; 125
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Forskningsöversikt (refereegranskat)abstract
- The exploration of the universe has recently entered a new era thanks to the multi-messenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic messengers (photons, neutrinos, cosmic rays and gravitational waves) from numerous origins. They give us information about their sources in the universe and the properties of the intergalactic medium. Moreover, multi-messenger astronomy opens up the possibility to search for phenomenological signatures of quantum gravity. On the one hand, the most energetic events allow us to test our physical theories at energy regimes which are not directly accessible in accelerators; on the other hand, tiny effects in the propagation of very high energy particles could be amplified by cosmological distances. After decades of merely theoretical investigations, the possibility of obtaining phenomenological indications of Planck-scale effects is a revolutionary step in the quest for a quantum theory of gravity, but it requires cooperation between different communities of physicists (both theoretical and experimental). This review, prepared within the COST Action CA18108 “Quantum gravity phenomenology in the multi-messenger approach”, is aimed at promoting this cooperation by giving a state-of-the art account of the interdisciplinary expertise that is needed in the effective search of quantum gravity footprints in the production, propagation and detection of cosmic messengers.
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| 2. |
- Freitas, Flavio L. M., 1986-, et al.
(författare)
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Recent political development threaten terrestrial mammal diversity in Brazil
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Recent political developments may weaken the legal protection of native vegetation in Brazil, which holds large areas of high biodiversity value. We assess the extent to which legislation protects terrestrial mammal species in Brazil. To this end, we quantify the natural population of mammal species in each fragment of native vegetation and relating this quantification to relevant legislation. We also assess the urgency of interventions to improve the protection of the mammal species. The results indicate that the legislation concerning private and public lands protects at least 40%, and about one-third, of the habitats where half of the threatened mammal species live, respectively. In scenarios of full compliance with relevant legislation, at least 40% of habitats supporting about one-third of these species are unprotected or undesignated lacking command and control regulations protecting the native vegetation. The implications of these results are discussed in light of recent policy developments in Brazil.
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| 3. |
- Öström, Henrik, et al.
(författare)
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Geometric structure and chemical bonding of acetylene adsorbed on Cu(110)
- 2004
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 565:2-3, s. 206-222
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Tidskriftsartikel (refereegranskat)abstract
- The chemical bonding and geometric structure of acetylene adsorbed on Cu(I 10) is analyzed using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) in combination with density functional theory (DFT) total energy geometry optimizations and spectral calculations. XPS reveals two different adsorbed species at liquid nitrogen temperature. The molecular alignment is deduced from angle-resolved XAS, revealing that in one site the molecules are aligned with the C-C axis along the [0 0 1] direction and in the other site with an average angle of 35degrees to the Cu rows. The position of the shape resonance is used to deduce a C-C bond length of 1.35 Angstrom, which is close to the values obtained from the DFT geometry optimizations. XES reveals strong sigma-pi mixing and new occupied states close to the Fermi level, originating from the out-of-plane pi* orbital, which becomes occupied upon adsorption in agreement with the Dewar-Chatt-Duncanson model of the bonding.
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