| 11. |
- Bergström, Stig M., et al.
(författare)
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Darriwili (Keskordoviitsiumi) δ13Corg kemostratigraafia koos graptoliitide biostratigraafiaga klassikalisel röstånga alal skåne maakonna loodeosas lõunarootsis
- 2020
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Ingår i: Estonian Journal of Earth Sciences. - : Estonian Academy Publishers. - 1736-4728. ; 69:3, s. 121-133
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Tidskriftsartikel (refereegranskat)abstract
- The largely covered Middle Ordovician succession in the classic geological Röstånga area in northwestern Scania has not been studied for some 80 years. A new drill core through a succession ranging from the lower–middle Darriwilian to the lower Sandbian has provided a unique opportunity to investigate the graptolite biostratigraphy and the δ13Corg chemostratigraphy, and clarify their stratigraphic relations, through this ~90 m thick interval, which is developed within a black shale facies. The lithology, biostratigraphy and chemostratigraphy are closely similar to those of the coeval strata in the Fågelsång area, southcentral Scania, including the presence of the Fågelsång Phosphorite, which was previously unrecorded in the Röstånga area. The new data are particularly important in providing evidence of the relations between graptolite biostratigraphy and δ13Corg chemostratigraphy. The Fågelsång3 and Röstånga2 drill core successions are currently the only Darriwilian sequences in the world where these relations have been well established.
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| 12. |
- Braglia, L., et al.
(författare)
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Understanding Solid-Gas Reaction Mechanisms by Operando Soft X-Ray Absorption Spectroscopy at Ambient Pressure
- 2020
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:26, s. 14202-14212
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Tidskriftsartikel (refereegranskat)abstract
- Ambient-pressure operando soft X-ray absorption spectroscopy (soft-XAS) was applied to study the reactivity of hydroxylated SnO(2 )nanoparticles toward reducing gases. H-2 was first used as a test case, showing that the gas phase and surface states can be simultaneously probed: Soft-XAS at the O K-edge gains sensitivity toward the gas phase, while at the Sn M-4,M-5-edges, tin surface states are explicitly probed. Results obtained by flowing hydrocarbons (CH4 and CH3CHCH2) unequivocally show that these gases react with surface hydroxyl groups to produce water without producing carbon oxides and release electrons that localize on Sn to eventually form SnO. The partially reduced SnO2-x layer at the surface of SnO2 is readily reoxidized to SnO2 by treating the sample with O-2 at mild temperatures (>200 degrees C), revealing the nature of "electron sponge" of tin oxide. The experiments, combined with DFT calculations, allowed devising of a mechanism for dissociative hydrocarbon adsorption on SnO2, involving direct reduction of Sn sites at the surface via cleavage of C-H bonds and the formation of methoxy- and/or methyl-tin species at the surface.
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| 13. |
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| 14. |
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| 15. |
- Jana, Somnath, et al.
(författare)
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Analysis of the linear relationship between asymmetry and magnetic moment at the M edge of 3d transition metals
- 2020
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Ingår i: Physical Review Research. - : American Physical Society. - 2643-1564. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- The magneto-optical response of Fe and Ni during ultrafast demagnetization is studied experimentally and theoretically. We have performed pump-probe experiments in the transverse magneto-optical Kerr effect (T-MOKE) geometry using photon energies that cover the M absorption edges of Fe and Ni between 40 and 72 eV. The magnetic asymmetry was obtained by forming the difference of reflected intensities obtained for two opposite orientations of the sample magnetization. Density functional theory (DFT) was used to calculate the magneto-optical response of different magnetic configurations, representing different types of excitations: long wavelength magnons, short wavelength magnons, and Stoner excitations. In the case of Fe, we find that the calculated asymmetry is strongly dependent on the specific type of magnetic excitation. Our modeling also reveals that during remagnetization Fe is, to a reasonable approximation, described by magnons, even though small nonlinear contributions could indicate some degree of Stoner excitations as well. In contrast, we find that the calculated asymmetry in Ni is rather insensitive to the type of magnetic excitations. However, there is a weak nonlinearity in the relation between asymmetry and the off-diagonal component of the dielectric tensor, which does not originate from the modifications of the electronic structure. Our experimental and theoretical results thus emphasize the need to consider a coupling between asymmetry and magnetization that may be more complex than a simple linear relationship. This insight is crucial for the microscopic interpretation of ultrafast magnetization experiments.
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| 16. |
- Mohseni, M., et al.
(författare)
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Chiral excitations of magnetic droplet solitons driven by their own inertia
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:2
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Tidskriftsartikel (refereegranskat)abstract
- The inertial effects of magnetic solitons play a crucial role in their dynamics and stability. Yet governing their inertial effects is a challenge for their use in real devices. Here, we show how to control the inertial effects of magnetic droplet solitons. Magnetic droplets are more strongly nonlinear and localized autosolitons than can form in current-driven nanocontacts. Droplets can be considered as dynamical particles with an effective mass. We show that the dynamical droplet bears a second excitation under its own inertia. These excitations comprise a chiral profile, and appear when the droplet resists the force induced by the Oersted field of the current injected into the nanocontact. We reveal the role of the spin torque on the excitation of these chiral modes and we show how to control these modes using the current and the field.
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| 17. |
- Norman, M., et al.
(författare)
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Association of Maternal SARS-CoV-2 Infection in Pregnancy With Neonatal Outcomes
- 2021
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Ingår i: Jama-Journal of the American Medical Association. - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 325:20, s. 2076-2086
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE The outcomes of newborn infants of women testing positive for SARS-CoV-2 in pregnancy is unclear. OBJECTIVE To evaluate neonatal outcomes in relation to maternal SARS-CoV-2 test positivity in pregnancy. DESIGN, SETTING, AND PARTICIPANTS Nationwide, prospective cohort study based on linkage of the Swedish Pregnancy Register, the Neonatal Quality Register, and the Register for Communicable Diseases. Ninety-two percent of all live births in Sweden between March 11, 2020, and January 31, 2021, were investigated for neonatal outcomes by March 8, 2021. Infants with malformations were excluded. Infants of women who tested positive for SARS-CoV-2 were matched, directly and using propensity scores, on maternal characteristics with up to 4 comparator infants. EXPOSURES Maternal test positivity for SARS-CoV-2 in pregnancy. MAIN OUTCOMES AND MEASURES In-hospital mortality; neonatal resuscitation; admission for neonatal care; respiratory, circulatory, neurologic, infectious, gastrointestinal, metabolic, and hematologic disorders and their treatments; length of hospital stay; breastfeeding; and infant test positivity for SARS-CoV-2. RESULTS Of 88 159 infants (49.0% girls), 2323 (1.6%) were delivered by mothers who tested positive for SARS-CoV-2. The mean gestational age of infants of SARS-CoV-2-positive mothers was 39.2 (SD, 2.2) weeks vs 39.6 (SD, 1.8) weeks for comparator infants, and the proportions of preterm infants (gestational age <37 weeks) were 205/2323 (8.8%) among infants of SARS-CoV-2-positive mothers and 4719/85 836 (5.5%) among comparator infants. After matching on maternal characteristics, maternal SARS-CoV-2 test positivity was significantly associated with admission for neonatal care (11.7% vs 8.4%; odds ratio [OR], 1.47; 95% CI, 1.26-1.70) and with neonatal morbidities such as respiratory distress syndrome (1.2% vs 0.5%; OR, 2.40; 95% CI, 1.50-3.84), any neonatal respiratory disorder (2.8% vs 2.0%; OR, 1.42; 95% CI, 1.07-1.90), and hyperbilirubinemia (3.6% vs 2.5%; OR, 1.47; 95% CI, 1.13-1.90). Mortality (0.30% vs 0.12%; OR, 2.55; 95% CI, 0.99-6.57), breastfeeding rates at discharge (94.4% vs 95.1%; OR, 0.84; 95% CI, 0.67-1.05), and length of stay in neonatal care (median, 6 days in both groups; difference, 0 days; 95% CI, -2 to 7 days) did not differ significantly between the groups. Twenty-one infants (0.90%) of SARS-CoV-2-positive mothers tested positive for SARS-CoV-2 in the neonatal period; 12 did not have neonatal morbidity, 9 had diagnoses with unclear relation to SARS-CoV-2, and none had congenital pneumonia. CONCLUSIONS AND RELEVANCE In a nationwide cohort of infants in Sweden, maternal SARS-CoV-2 infection in pregnancy was significantly associated with small increases in some neonatal morbidities. Given the small numbers of events for many of the outcomes and the large number of statistical comparisons, the findings should be interpreted as exploratory.
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| 18. |
- Peng, Shanchi, et al.
(författare)
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The Cambrian Period
- 2020
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Ingår i: Geologic Time Scale. - 9780128243619 - 9780128243633 ; 2, s. 565-565
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Bokkapitel (refereegranskat)abstract
- Appearance of metazoans with mineralized skeletons, “explosion” in biotic diversity and disparity, infaunalization of the substrate, occurrence of metazoan Konservat Fossil-lagerstätten, establishment of most invertebrate phyla, strong faunal provincialism, dominance of trilobites, generally warm climate but with possibleglacial-interglacial cycles in the later part, opening of the Iapetus Ocean, progressive equatorial drift and separation of Laurentia, Baltica, Siberia, and Avalonia from Gondwana characterize the Cambrian Period.
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| 19. |
- Peng, Shanchi, et al.
(författare)
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Trilobites
- 2020
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Ingår i: Geologic Timescale 2020. - 9780128243626 - 9780128243619 ; 1, s. 36-36
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Bokkapitel (refereegranskat)abstract
- Trilobites are marine arthropods that appeared in Cambrian Epoch 2 and became extinct at the end of the Permian. In some Paleozoic deposits, they number among the most abundant macrofossils. Trilobites are important for early Paleozoic biostratigraphy, especially Cambrian.
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| 20. |
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