| 1. |
- Albanesi, Guillermo L., et al.
(författare)
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Darriwilian (Middle Ordovician) delta C-13(carb) chemostratigraphy in the Precordillera of Argentina: Documentation of the middle Darriwilian Isotope Carbon Excursion (MDICE) and its use for intercontinental correlation
- 2013
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 1872-616X .- 0031-0182. ; 389, s. 48-63
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Tidskriftsartikel (refereegranskat)abstract
- Although documented from Estonia, Latvia, Sweden, eastern North America, and China, the Middle Ordovician (Darriwilian) positive delta C-13 excursion known as the MDICE has previously not been recognized with certainty in South America. The most promising region in South America for detailed Middle Ordovician carbon isotope research is the Precordillera of western Argentina, where there are many excellent exposures of biostratigraphically well-dated carbonate successions spaning the Tremadocian through Sandbian stratigraphic interval. For this project, we collected numerous isotope and conodont samples from the middle Darriwilian Las Chacritas and Aguaditas formations at their type localities, which yielded important biostratigraphic data as well as informative delta C-13(carb) values. In the E. pseudoplanus Zone in the upper half of the Las Chacritas Formation, there is a relatively modest but distinct delta C-13(carb) excursion. Because its stratigraphic position and magnitude closely agree with the MDICE in other parts of the world, we recognize it as the first firm record of this excursion in South America. The fact that the delta C-13(carb) curve from the Las Aguaditas Formation shows no such excursion is due to the existence of a stratigraphic gap between the Lower and Middle Members of this formation that cuts out the excursion interval. The Precordilleran MDICE is used for detailed long-range correlations with successions in Baltoscandia, Newfoundland, and China illustrating the usefulness of also this delta C-13(carb) excursion as a global stratigraphic tool. A recent proposal of a greatly extended chronostratigraphic range of the Table Head Group on Newfoundland is rejected based on well-established biostratigraphic evidence. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Albani, D, et al.
(författare)
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Insulin-like growth factor 1 receptor polymorphism rs2229765 and circulating interleukin-6 level affect male longevity in a population-based prospective study (Treviso Longeva--TRELONG).
- 2011
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Ingår i: The Aging Male. - 1368-5538. ; 14:4, s. 257-264
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-like growth factor 1 (IGF-1) signaling modulation has been associated with increased lifespan in model organisms, while high levels of circulating interleukin-6 (IL-6) are a marker of disability and mortality. In the prospective, population-based "Treviso Longeva"--TRELONG Study from Italy (n = 668, age range 70-105.5 years at baseline, followed for seven years) we investigated the effects of survival on the IGF-1 receptor (IGF-1R) gene polymorphism rs2229765, the IL-6 gene promoter polymorphism rs1800795, and plasma concentrations of IGF-1 and IL-6, alone or in combination. We found a sex-dependent effect for the IGF-1R rs2229765 polymorphism, as male carriers of the homozygous A/A genotype survived longer, while the IL-6 rs1800795 genotype did not influence overall or sex-specific longevity. Higher IL-6 levels were more detrimental for survival among males than females, while IGF-1 had no dose-response effect. These findings sustain the hypothesis that sex-specific longevity relies on detectable differences in genetic and biochemical parameters between males and females.
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| 3. |
- Andersson, Mats, et al.
(författare)
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Sparsity Optimization in Design of Multidimensional Filter Networks
- 2015
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Ingår i: Optimization and Engineering. - : Springer. - 1389-4420 .- 1573-2924. ; 16:2, s. 259-277
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Tidskriftsartikel (refereegranskat)abstract
- Filter networks are used as a powerful tool used for reducing the image processing time and maintaining high image quality.They are composed of sparse sub-filters whose high sparsity ensures fast image processing.The filter network design is related to solvinga sparse optimization problem where a cardinality constraint bounds above the sparsity level.In the case of sequentially connected sub-filters, which is the simplest network structure of those considered in this paper, a cardinality-constrained multilinear least-squares (MLLS) problem is to be solved. Even when disregarding the cardinality constraint, the MLLS is typically a large-scale problem characterized by a large number of local minimizers, each of which is singular and non-isolated.The cardinality constraint makes the problem even more difficult to solve.An approach for approximately solving the cardinality-constrained MLLS problem is presented.It is then applied to solving a bi-criteria optimization problem in which both thetime and quality of image processing are optimized. The developed approach is extended to designing filter networks of a more general structure. Its efficiency is demonstrated by designing certain 2D and 3D filter networks. It is also compared with the existing approaches.
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| 4. |
- Bondarenko, Alexander, et al.
(författare)
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Overview of Touché 2022 : Argument Retrieval
- 2022
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Ingår i: Experimental IR Meets Multilinguality, Multimodality, and Interaction (CLEF 2022). - Cham : Springer Nature. - 9783031136436 - 9783031136429 ; , s. 311-336
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Konferensbidrag (refereegranskat)abstract
- This paper is a condensed report on the third year of the Touche lab on argument retrieval held at CLEF 2022. With the goal to foster and support the development of technologies for argument mining and argument analysis, we organized three shared tasks in the third edition of Touche: (a) argument retrieval for controversial topics, where participants retrieve a gist of arguments from a collection of online debates, (b) argument retrieval for comparative questions, where participants retrieve argumentative passages from a generic web crawl, and (c) image retrieval for arguments, where participants retrieve images from a focused web crawl that show support or opposition to some stance.
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| 5. |
- Bondarenko, Artem, 1992-, et al.
(författare)
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Stochastic dynamics of strongly-bound magnetic vortex pairs
- 2017
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Ingår i: AIP Advances. - : American Institute of Physics (AIP). - 2158-3226. ; 7:5
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that strongly-bound spin-vortex pairs exhibit pronounced stochastic behaviour. Such dynamics is due to collective magnetization states originating from purely dipolar interactions between the vortices. The resulting thermal noise exhibits telegraph-like behaviour, with random switching between different oscillation regimes observable at room temperature. The noise in the system is further studied by varying the external field and observing the related changes in the frequency of switching and the probability for different magnetic states and regimes. Monte Carlo simulations are used to replicate and explain the experimental observations.
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| 6. |
- Bondarenko, Nina G., et al.
(författare)
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Multi-polaron solutions, nonlocal effects and internal modes in a nonlinear chain
- 2019
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Ingår i: Journal of Physics. - : Institute of Physics (IOP). - 0953-8984 .- 1361-648X. ; 31:41
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Tidskriftsartikel (refereegranskat)abstract
- Multipolaron solutions were studied in the framework of the Holstein one-dimensional molecular crystal model. The study was performed in the continuous limit where the crystal model maps into the nonlinear Schrodinger equation for which a new periodic dnoidal solution was found for the multipolaron system. In addition, the stability of the multi-polaron solutions was examined, and it was found that dnoidal and dnoidal solutions stabilize in different ranges of the parameter space. Moreover, the model was studied under the influence of nonlocal effects and the polaronic dynamics was described in terms of internal solitonic modes.
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| 7. |
- Bondarenko, Nina G., et al.
(författare)
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Spin polaronics : Static and dynamic properties of spin polarons in La-doped CaMnO4
- 2019
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 100:13
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Tidskriftsartikel (refereegranskat)abstract
- The static and dynamic properties of spin polarons in La-doped CaMnO3 are explored theoretically, by means of an effective low-energy Hamiltonian. All parameters of the effective Hamiltonian are evaluated from first-principles theory. The Hamiltonian is used to investigate the temperature stability as well as the response to an external applied electric field, for spin polarons in bulk, surface, and as single two-dimensional layers. Technically this involves atomistic spin-dynamics simulations in combination with kinetic Monte Carlo simulations. Where a comparison can be made, our simulations exhibit excellent agreement with available experimental data and previous theory. Remarkably, we find that excellent control of the mobility of spin polarons in this material can be achieved, and that the critical parameters deciding this are the temperature and strength of the applied electrical field. We outline different technological implications of spin polarons, and point to spin polaronics as an emerging subfield of nanotechnology. In particular, we demonstrate that it is feasible to write and erase information on an atomic scale, by use of spin polarons in CaMnO3.
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| 8. |
- Bondarenko, Nina, et al.
(författare)
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Hole bipolaron formation at (100) MgO/CaO epitaxial interface
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:12, s. 125118-
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Tidskriftsartikel (refereegranskat)abstract
- Hole localization accompanying the formation of a cation vacancy in bulk MgO and CaO and at the (100) MgO/CaO interface is described using the Heyd-Scuseria-Ernzerhof hybrid functionals and DFT + U method. The ground state is found to be the O-1-O-1 bipolaronic configuration both in bulk oxides and at their interfaces. The ground-state magnetic configuration is a triplet, which has an energy only about 1-2 meV lower than that of the singlet state. The one-centered O-2-O-0 bipolaron was found to be metastable with its stability being enhanced at the interfaces compared to that in bulk oxides. Possible transition between different biplaronic configurations at the interface are analyzed for chosen configurations.
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| 9. |
- Bondarenko, Nina, et al.
(författare)
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Polaron mobility in oxygen-deficient and lithium-doped tungsten trioxide
- 2015
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : AMER PHYSICAL SOC. - 1098-0121 .- 1550-235X. ; 92:16
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Tidskriftsartikel (refereegranskat)abstract
- Electron localization and polaron mobility in oxygen-deficient as well as Li-doped monoclinic tungsten trioxide have been studied in the adiabatic limit in the framework of density functional theory. We show that small polarons formed in the presence of oxygen vacancy prefer the bipolaronicW(5+)-W5+ configuration, whereas the W6+-W4+ configuration is found to be metastable. Our calculations suggest that bipolarons are tightly bound by the vacancy and therefore largely immobile. On the contrary, polarons formed as a result of Li intercalation can be mobile; the activation energy for polaron jumping in this case varies between 98 and 124 meV depending on the crystallographic direction. The formation of W5+-W5+ bipolarons in Li-WO3 is possible. When situated along [001] the bipolaronic configuration is 8 meV lower in energy than two separate W5+ polarons.
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| 10. |
- Bondarenko, N., et al.
(författare)
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Spin-polaron formation and magnetic state diagram in La-doped CaMnO3
- 2017
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 95:22
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Tidskriftsartikel (refereegranskat)abstract
- LaxCa1-xMnO3 (LCMO) has been studied in the framework of density functional theory (DFT) using Hubbard-U correction. We show that the formation of spin polarons of different configurations is possible in the G-type antiferromagnetic phase. We also show that the spin-polaron (SP) solutions are stabilized due to an interplay of magnetic and lattice effects at lower La concentrations and mostly due to the lattice contribution at larger concentrations. Our results indicate that the development of SPs is unfavorable in the C- and A-type antiferromagnetic phases. The theoretically obtained magnetic state diagram is in good agreement with previously reported experimental results.
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