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| 2. |
- Librado, P., et al.
(författare)
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The origins and spread of domestic horses from the Western Eurasian steppes
- 2021
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 598, s. 634-640
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region. Domestication of horses fundamentally transformed long-range mobility and warfare(1). However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling(2-4) at Botai, Central Asia around 3500 bc(3). Other longstanding candidate regions for horse domestication, such as Iberia(5) and Anatolia(6), have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association(7) between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc(8,9) driving the spread of Indo-European languages(10). This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture(11,12).
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| 3. |
- Asmolov, V.G., et al.
(författare)
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Partitioning of Zr, U and FP between Molten Oxidic and Metallic Corium
- 2004
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Ingår i: Proceeding of MASCA Seminar.
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Konferensbidrag (refereegranskat)abstract
- Interaction of molten corium and liquid iron/stainless steel has been studied in different tests of theMASCA-1 program. These tests utilized the technology of induction melting in a cold crucible. Themasses of tested corium were approximately 0.5, 2 and 100 kg. Representative quantities of Mo, Ru,SrO, BaO, CeO2 and La2O3 served as fission product simulants.After the suboxidized melt - steel interaction U and Zr have been found in the metallic phase.To quantify the partitioning of Zr, U and fission products an extensive experimental program has beenperformed. The following key parameters have been identified: oxygen potential in the melt (degree ofZr-oxidation), the corium/steel mass ratio and U/Zr ratio. The paper discusses the influence of theseparameters on the partitioning of the main species.
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| 4. |
- Khabensky, V. B., et al.
(författare)
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Effect of temperature gradient on chemical element partitioning in corium pool during in-vessel retention
- 2018
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Ingår i: Nuclear Engineering and Design. - : Elsevier Ltd. - 0029-5493 .- 1872-759X. ; 327, s. 82-91
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents some results of the ISTC (International Science and Technology Center)-financed project ‘Investigation of Corium Melt Interaction with NPP Reactor Vessel Steel’ (METCOR). In the METCOR experiments the metallic phase of a two-liquid system was produced by the interaction between hot suboxidized corium and cooled VVER vessel steel, with the steel being corroded. Models of corrosion mechanisms in the considered conditions are used to systematize data on the limiting temperature of corrosion/(dissolution) of the vessel steel. A considerable influence of thermal gradient conditions is shown, which has to be taken into account in the analysis of molten pool behaviour.
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| 6. |
- Bechta, Sevostian, et al.
(författare)
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Influence of corium oxidation on fission product release from molten pool
- 2010
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 240:5, s. 1229-1241
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Tidskriftsartikel (refereegranskat)abstract
- Qualitative and quantitative determination of the release of low-volatile fission products and core materialsfrom molten oxidic corium was investigated in the EVAN project under the auspices of ISTC. Theexperiments carried out in a cold crucible with induction heating and RASPLAV test facility are described.The results are discussed in terms of reactor application; in particular, pool configuration, melt oxidationkinetics, critical influence of melt surface temperature and oxidation index on the fission productrelease rate, aerosol particle composition and size distribution. The relevance of measured high releaseof Sr from the molten pool for the reactor application is highlighted. Comparisons of the experimentaldata with those from the COLIMA CA-U3 test and the VERCORS tests, as well as with predictions fromIVTANTHERMO and GEMINI/NUCLEA codes are made. Recommendations for further investigations areproposed following the major observations and discussions.
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| 7. |
- Bechta, Sevostian, et al.
(författare)
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Corium phase equilibria based on MASCA, METCOR and CORPHAD results
- 2008
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 238:10, s. 2761-2771
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Tidskriftsartikel (refereegranskat)abstract
- Experimental data on component partitioning between suboxidized corium melt and steel in the invessel melt retention (IVR) conditions are compared. The data are produced within the OECD MASCAprogram and the ISTC CORPHAD project under close-to-isothermal conditions and in the ISTC METCORproject under thermal gradient conditions. Chemical equilibrium in the U–Zr–Fe(Cr,Ni,. . .)–O system isreached in all experiments. In MASCA tests the molten pool formed under inert atmosphere has twoimmiscible liquids, oxygen-enriched (oxidic) and oxygen-depleted (metallic), resulting of the miscibilitygap of the mentioned system. Sub-system data of the U–Zr–Fe(Cr,Ni,. . .)–O phase diagram investigatedwithin the ISTC CORPHAD project are interpreted in relation with the MASCA results. In METCOR teststhe equilibrium is established between oxidic liquid and mushy metallic part of the system. Results ofcomparison are discussed and the implications for IVR noted.
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| 8. |
- Nosikov, I. A., et al.
(författare)
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Testing the method of transverse displacements for calculating paths of the HF radio wave propagation in three dimensional inhomogeneous media
- 2015
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Ingår i: 2015 1st URSI Atlantic Radio Science Conference, URSI AT-RASC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9789090086286
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Konferensbidrag (refereegranskat)abstract
- Propagation of the Russian Academy of Sciences (WD IZMIRAN), Kaliningrad, Russia There are two approaches for radio wave ray tracing when the endpoints of the ray are fixed. The standard approach is the shooting method where a ray is sent out in some direction and its landing point is used to modify the shooting direction and obtain the desired endpoint. However, there is no systematic, universal algorithm for refining the shooting direction. Another approach is based on direct utilization of the variational principle for the optical path (Fermat’s principle). The idea is to transform an arbitrary trajectory to an optimal one, while the endpoints of the trajectory are kept fixed according to the boundary conditions.
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| 9. |
- Tomar, AS, et al.
(författare)
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Retinoblastoma seeds: impact on American Joint Committee on Cancer clinical staging
- 2023
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Ingår i: The British journal of ophthalmology. - : BMJ. - 1468-2079 .- 0007-1161. ; 107:1, s. 127-132
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether the American Joint Committee on Cancer (AJCC) clinical category cT2b needs to be subclassified by the type and distribution of retinoblastoma (RB) seeding.MethodsMulticentre, international registry-based data were collected from RB centres enrolled between January 2001 and December 2013. 1054 RB eyes with vitreous or subretinal seeds from 18 ophthalmic oncology centres, in 13 countries within six continents were analysed. Local treatment failure was defined as the use of secondary enucleation or external beam radiation therapy (EBRT) and was estimated with the Kaplan-Meier method.ResultsClinical category cT2b included 1054 eyes. Median age at presentation was 16.0 months. Of these, 428 (40.6%) eyes were salvaged, and 430 (40.8%) were treated with primary and 196 (18.6%) with secondary enucleation. Of the 592 eyes that had complete data for globe salvage analysis, the distribution of seeds was focal in 143 (24.2%) and diffuse in 449 (75.8%). The 5-year Kaplan-Meier cumulative globe-salvage (without EBRT) was 78% and 49% for eyes with focal and diffuse RB seeding, respectively. Cox proportional hazards regression analysis confirmed a higher local treatment failure risk with diffuse seeds as compared with focal seeds (hazard rate: 2.8; p<0.001). There was insufficient evidence to prove or disprove an association between vitreous seed type and local treatment failure risk(p=0.06).ConclusionThis international, multicentre, registry-based analysis of RB eyes affirmed that eyes with diffuse intraocular distribution of RB seeds at diagnosis had a higher risk of local treatment failure when compared with focal seeds. Subclassification of AJCC RB category cT2b into focal vs diffuse seeds will improve prognostication for eye salvage.
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