85 research outputs found
Interrelation of posterior cranial fossa parameters and size characteristics of human skull in different craniotypes
The aim of this work was to study the correlation between the linear dimensions of the posterior cranial fossa and linear and angular parameters of the skull, depending on the magnitude of basilar angle. Material studies provided one hundred skulls of adult humans, divided into three craniotypes. Used by craniotopometric method measurements of these parameters with subsequent calculation of estimated average values and drawing the correlation model. The results showed that the most intimate degree of multidirectional communication studied parameters were observed in platibasilar craniotype have flexibasilar craniotype strong positive dependence is present in the width of the posterior fossa, the mediobasilar craniotipe connection parameters predominantly moderate and mild. Dimensions cerebellar pits exposed to greater variabilit
Importance of full Coulomb interactions for understanding the electronic structure of delta-Pu
Contains fulltext :
84373.pdf (preprint version ) (Open Access)5 p
Approximative treatment of 5f-systems with partial localization due to intra-atomic correlations
Increasing experimental and theoretical evidence points towards a dual nature
of the 5 electrons in actinide-based strongly correlated metallic compounds,
with some 5 electrons being localized and others delocalized. In a recent
paper (PRB xxx, 2004), we suggested the interplay of intra-atomic correlations
as described by Hund's rules and a weakly anisotropic hopping (hybridization)
as a possible mechanism. The purpose of the present work is to provide a first
step towards a microscopic description of partial localization in solids by
analyzing how well various approximation schemes perform when applied to small
clusters. It is found that many aspects of partial localization are described
appropriately both by a variational wavefunction of Gutzwiller type and by a
treatment which keeps only those interactions which are present in LDA+U
calculations. In contrast, the energies and phase diagram calculated within the
Hartree Fock approximation show little resemblence with the exact results.
Enhancement of hopping anisotropy by Hund's rule correlations are found in all
approximations.Comment: 9 pages, 9 figure
Magnetic and Charge Correlations in La{2-x-y}Nd_ySr_xCuO_4: Raman Scattering Study
Two aspects in connection with the magnetic properties of
La_{2-x-y}Nd_ySr_xCuO_4 single crystals are discussed. The first is related to
long wavelength magnetic excitations in x = 0, 0.01, and 0.03 La_{2-x}Sr_xCuO_4
detwinned crystals as a function of doping, temperature and magnetic field. Two
magnetic modes were observed within the AF region of the phase diagram. The one
at lower energies was identified with the spin-wave gap induced by the
antisymmetric DM interaction and its anisotropic properties in magnetic field
could be well explained using a canonical form of the spin Hamiltonian. A new
finding was a magnetic field induced mode whose dynamics allowed us to discover
a spin ordered state outside the AF order which was shown to persist in a 9 T
field as high as 100 K above the N\'eel temperature T_N for x = 0.01. For these
single magnon excitations we map out the Raman selection rules in magnetic
fields and demonstrate that their temperature dependent spectral weight is
peaked at the N\'eel temperature. The second aspect is related to phononic and
magnetic Raman scattering in La_{2-x-y}Nd_ySr_xCuO_4 with three doping
concentrations: x = 1/8, y = 0; x = 1/8, y = 0.4; and x = 0.01, y = 0. We
observed that around 1/8 Sr doping and independent of Nd concentration there
exists substantial disorder in the tilt pattern of the CuO_6 octahedra in both
the orthorhombic and tetragonal phases which persist down to 10 K and are
coupled to bond disorder in the cation layers. The weak magnitude of existing
charge/spin modulations in the Nd doped structure did not allow us to detect
specific Raman signatures on lattice dynamics or two-magnon scattering around
2200 cm-1.Comment: 26 pages, 22 figure
Asymptotic Expansions for Stationary Distributions of Perturbed Semi-Markov Processes
New algorithms for computing of asymptotic expansions for stationary
distributions of nonlinearly perturbed semi-Markov processes are presented. The
algorithms are based on special techniques of sequential phase space reduction,
which can be applied to processes with asymptotically coupled and uncoupled
finite phase spaces.Comment: 83 page
Modified GBIG Scenario as an Alternative for Dark Energy
We construct a DGP-inspired braneworld model where induced gravity on the
brane is modified in the spirit of gravity and stringy effects are taken
into account by incorporation of the Gauss-Bonnet term in the bulk action. We
explore cosmological dynamics of this model and we show that this scenario is a
successful alternative for dark energy proposal. Interestingly, it realizes the
phantom-like behavior without introduction of any phantom field on the brane
and the effective equation of state parameter crosses the cosmological constant
line naturally in the same way as observational data suggest.Comment: 16 pages, 6 figures, Accepted for publication in JCA
A Braneworld Dark Energy Model with Induced Gravity and the Gauss-Bonnet Effect
We construct a holographic dark energy model with a non-minimally coupled
scalar field on the brane where Gauss-Bonnet and Induced Gravity effects are
taken into account. This model provides a wide parameter space with several
interesting cosmological implications. Especially, the equation of state
parameter of the model crosses the phantom divide line and it is possible to
realize bouncing solutions in this setup.Comment: 20 pages, 3 eps figures, to appear in IJT
Creation of the precision magnetic spectrometer SCAN-3
The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article
The origins and spread of domestic horses from the Western Eurasian steppes
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).Descriptive and Comparative Linguistic
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