The ratio of the elastic e(+)p to e(-)p scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected ...contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.6 and 1.0 GeV and at lepton scattering angles between 15° and 105°. The data obtained show evidence of a significant two-photon exchange effect. The results are compared with several theoretical predictions.
The settlement of Ust-Voikar is one of the unique multilayered archaeological sites of north-west Siberia. The settlement was inhabited in the late Middle Ages and the early modern period by the Ob ...Ugrian or northern Khanty ethnographic group. Due to the presence of a frozen cultural layer ruins of wooden residential buildings and other organic materials are well preserved. Plant macroremain, pollen and non-pollen palynomorph (NPP) analyses were applied to samples of the cultural layer from different parts of buildings and from space between them to establish the vegetation cover, plants used by the population, and differences between functional zones in the buildings. For the first time, the NPP analysis combined with statistical methods were used to clarify the settlement planning and human economic activity. Plant communities around the Ust-Voikar settlement were typical for the northern taiga subzone, some settlement's areas were overgrown with weed vegetation. Residents did not engage in agriculture and used local plant resources for construction, medicinal and food purposes. According to macroremain and NPP data were reconstructed (i) the use of spruce branches and cereal bedding indoors and outdoors on wet sites; (ii) the careful use of fire indoors; (iii) the presence of animals indoors; and (iv) whipworm infection. The cluster analysis and principal component analysis of NPPs helped to clarify the planning affiliations of several samples with the unclear origin and to suggest ways in which archaeological objects were used by the inhabitants.
Display omitted
•The largest endorheic Siberian Lake Chany appeared only 3.6 cal ka BP.•The basin of the lake was a swampy landscape ca. 9–3.6 ka BP with a very low rate of sedimentation.•The lake ...was shallow 3.6–1 ka BP, and then became deep, similar to the modern one.•Development of the lake was controlled by climate and specific topography of its catchment.
Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia. Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity to gain more knowledge about environmental changes in the West Siberian interior during the Holocene and about the evolution of the lake itself. Sediment cores obtained from the Yarkov sub-basin of the lake in 2008 have been comprehensively studied by a number of approaches including sedimentology and AMS dating, pollen, diatom and chironomid analyses (with statistical interpretation of the results), mineralogy of authigenic minerals and geochemistry of plant lipids (biomarker analysis.). Synthesis of new results presented here and published data provides a good justification for our hypothesis that Lake Chany is very young, no older than 3.6 ka BP. Before that, between 9 and 3.6 ka BP, the Chany basin was a swampy landscape with a very low sedimentation rate; it could not be identified as a water body. In the early lake phase, between 3.6 and 1.5 ka BP, the lake was shallow, 1.2–3.5 m in depth, and it rose to its modern size, up to 6.5 m in depth, during the last millennium. Our data reveal important changes in the understanding of the history of this large endorheic lake, as before it was envisioned as a large lake with significant changes in water level since ca. 14 ka BP. In addition to hydrology, our proxies provide updates and details of the regional vegetation and climate change since ca. 4 ka BP in the West-Siberian forest-steppe and steppe. As evolution of the Chany basin is dependent on hydroclimatic changes in a large region of southern West Siberia, we compare lake-level change and climate-change proxies from the other recently and most comprehensively studied lakes of the region.
Electromagnetic calorimeter for Belle II Belle-ECL; Aulchenko, V; Bobrov, A ...
Journal of physics. Conference series,
01/2015, Letnik:
587, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The electromagnetic calorimeter of the BELLE II detector for experiments at Super B-factory SuperKEKB is briefly described. The project of the calorimeter upgrade to meet severe background conditions ...expected at the upgraded KEK B factory is presented.
A comprehensive paleoecological study of permafrost peat deposits from three locations in the middle reaches of the Yuribei River in the subzone of modern subarctic shrub tundra of the Yamal ...Peninsula has been performed. Based on the results of palynological and carpological methods and of radiocarbon dating, the changes in regional and local vegetation and climatic conditions of Central Yamal in the Late Glacial and the Postglacial periods are reconstructed. It is found that shrubby tundra with
Betula nana
was widespread in this area under climatic conditions close to modern ones in the Younger Dryas about 12.6–11.7 cal ka BP. The penetration of tree species (
Betula
sect.
Betula
,
Picea obovata
, and
Larix sibirica
) and accompanying boreal herbaceous plants began due to more favorable climatic conditions during the Early Holocene warming about 10.2–9.7 cal ka BP. The most favorable conditions for the growth of birch tree, larch, and spruce existed in Central Yamal in the Early and the Middle Holocene in the range of 10.2–4.4 cal ka BP. At that time, open woodlands or even closed forests were common, and the climate was much warmer than the modern one. Forest vegetation degraded and open landscapes with tundra communities were formed at the end of the Middle Holocene (4.5–4.4 cal ka BP). The climatic conditions became similar to modern ones.
PDF
