156 research outputs found

    14C dating to study the development of soils in the forest-steppe of the central russian upland as a result of bioclimatic changes and long-term cultivation

    Get PDF
    Temporal changes in soils of forest landscapes of the forest-steppe zone - Haplic Luvisols and Greyzemic Phaeozems - under the impact of Holocene climate changes (natural factor) and long-term cultivation (anthropogenic factor) were studied on level interfluves of the Central Russian Upland. To study soil evolution under the impact of climate changes, soil chronosequences of archaeological sites - paleosols buried under ramparts of ancient settlements and background surface soils of adjacent areas - were analyze

    Expansionfree Fluid Evolution and Skripkin Model in f(R) Theory

    Full text link
    We consider the modified f(R)f(R) theory of gravity whose higher order curvature terms are interpreted as a gravitational fluid or dark source. The gravitational collapse of a spherically symmetric star, made up of locally anisotropic viscous fluid, is studied under the general influence of the curvature fluid. Dynamical equations and junction conditions are modified in the context of f(R) dark energy and by taking into account the expansionfree evolution of the self-gravitating fluid. As a particular example, the Skripkin model is investigated which corresponds to isotropic pressure with constant energy density. The results are compared with corresponding results in General Relativity.Comment: 18 pages, accepted for publication Int. J. Mod. Phys.

    Expansion-Free Cavity Evolution: Some exact Analytical Models

    Full text link
    We consider spherically symmetric distributions of anisotropic fluids with a central vacuum cavity, evolving under the condition of vanishing expansion scalar. Some analytical solutions are found satisfying Darmois junction conditions on both delimiting boundary surfaces, while some others require the presence of thin shells on either (or both) boundary surfaces. The solutions here obtained model the evolution of the vacuum cavity and the surrounding fluid distribution, emerging after a central explosion. This study complements a previously published work where modeling of the evolution of such kind of systems was achieved through a different kinematical condition.Comment: 9 pages, Revtex. Typos corrected. Published in Int. J. Mod. Phys.

    Expansion-Free Evolving Spheres Must Have Inhomogeneous Energy Density Distributions

    Full text link
    In a recent paper a systematic study on shearing expansion-free spherically symmetric distributions was presented. As a particular case of such systems, the Skripkin model was mentioned, which corresponds to a nondissipative perfect fluid with a constant energy density. Here we show that such a model is inconsistent with junction conditions. It is shown that in general for any nondissipative fluid distribution, the expansion-free condition requires the energy density to be inhomogeneous. As an example we consider the case of dust, which allows for a complete integration.Comment: 8 pages, Latex. To appear in Phys. Rev.D. Typos correcte

    MONKS AND ICON PAINTERS FROM THE SPASO-ANDRONIKOV MONASTERY, MOSCOW

    Get PDF
    In the Monastery of Our Saviour and St. Andronicus in Moscow, skeletal remains of clerics and of (possibly) famous icon painters were discovered. The bones were radiocarbon dated, and concentrations of trace elements in bone tissues were measured. From tombs 1-4, the (14)C dates obtained from human bones (likely monks) and from associated wood date to the 14th-15th centuries AD, as expected. Trace element concentrations indicate signs of fasting. Tomb 5 contained 2 burials; these Could belong to the famous icon painters Rublev and Chernyi. Indeed, the bones show high concentrations of lead, zinc, and copper, which is typical for remains of artists and metallurgists. The WC dates of the 2 skeletons, however, differ by 200 yr, and seem to be too old for Rublev and Chernyi. At this stage, it is not clear if the burials can be assigned to these painters.</p

    Application of remote monitoring and ground-based sensing in pastoralism

    Get PDF
    The development and implementation of an innovative system applying digital aerospace technologies in pastoralism constitute one of the current trends in agricultural development designed to solve numerous problems associated with soil fertility restoration in grazing pastures. Here, a promising line of research is to explore the feasibility of using satellite systems for an overall nutrient yield assessment per hectare of grazing land. The present article describes a comprehensive approach to the optimization of pastoralism that is based on remote methods for assessing pasture fertility using unmanned aerial vehicles (UAVs) and artificial Earth satellites. An analysis of existing methodological approaches reveals that the formalization of prediction processes is complicated by the lack of a theoretical basis for creating appropriate model-algorithmic support. The data on vegetation index dynamics and the nutritional values of forage plants obtained by interpreting imagery from a UAV camera and the multispectral cameras of a satellite service, as well as data from a portable handheld nitrogen sensor, were compared with the actual nutritional values of pasture plants. The study results provide a means to optimize the grouping of grazing animals, taking into account the actual possibility of achieving an increase in live weight. The provided findings indicate the possibility of achieving an additional 11.06% increase in daily live weight gain in young sheep (Jalgin Merino) when keeping them in pasture areas having a vegetation index of at least 0.5. Remote monitoring based on satellite service allows more efficient use of pastures. Study shows a positive relationship between remote sensing NDVI and feed nutritional value. Animal grazing optimization provides an additional 11.06% increase in live weight gain

    Some problems in the study of the chronology of the ancient nomadic cultures in Eurasia (9th - 3rd centuries BC)

    Get PDF
    This research is focused on the chronological investigations of ancient nomads belonging to the Scythian cultures which occupied the steppe and forest-steppe zones of Eurasia during the 9th-3rd centuries BC. The 14C dates for the pre-scythian and early scythian time in both Europe and Asia are presented and compared to their chronological position based on archaeological evidence. The first 14C dates have been produced for the Scythian time monuments located in the Lower Volga River basin, Urals and Transurals regions. Their chronological positions are compared with the position of the monuments of Southern Siberia and Central Asia. It was shown that the nomadic cultures belonging to the Scythian culture began to exist over the wide territory of Eurasia from the 9th-8th centuries cal BC and there are some monuments which may be synchronous to the Arzhan royal barrow (the oldest monument known). A list of new 14C dates and a map of the monuments are presented

    A chronology of the Scythian antiquities of Eurasia based on new archaeological and C-14 data

    Get PDF
    The paper is compares the chronology of the monuments of the Scythian epoch located in the east and west of the Eurasian steppe zone on the basis of both archaeological and radiocarbon data. The lists of C-14 dates for the monuments located in different parts of Eurasia are presented according to the periods of their existence. Generally, the C-14 dates are confirmed the archaeological point of view and allow us to compare the chronological position of the European and Asian Scythian monuments on the united C-14 time scale

    Review of experimental results from SND detector

    Get PDF
    The review of experimental results obtained with SND detector at VEPP-2M e+ee^+e^- collider in the energy region s=0.36\sqrt[]{s}=0.36 -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed ϕ\phi-meson rare decays, ϕ\phi-meson parameters measurements, studies of e+eπ+ππ0e^+e^-\to\pi^+\pi^-\pi^0 process dynamics, η\eta and KSK_S mesons rare decays, η\eta and ϕ\phi mesons conversion decays, and study of the e+ee^+e^- annihilation into hadrons.Comment: 12 pages and 6 figures. Talk given at the IX International Conference on Hadron Spectroskopy, Protvino, Russia, August 25 - September 1, 200
    corecore