The modern principles in treatment of Legg – Calve – Perthes syndrome in children

The aim: to improve the results of treatment of degenerative hip’s diseases in children by means of pathogenetic pattern. Methods and Materials. 56 children with Legg — Calve — Perthes syndrome aged from 4 to 12 years and 20 children of control group without hip’s diseases have been studied. Results. The modern principles of surgical treatment of Legg — Calve — Perthes syndrome in children have been identified. Conclusion. The results of surgical treatment of patients with a different degree of pathological process depending on a type of surgery (osteoplastic surgery, formation of vascularizing autotransplant, varus osteotomy, rotational intertrochanteric osteotomy) have been presented

Compaction of granular graphite in a vertically vibrating container with restricted geometry

The compaction of vertically vibrating granular materials (highly dissipative media composed of macroscopic grains that interact by means of contact forces) with restricted geometry is examined stroboscopically. Possible interpretation of the observed picture of compaction is discussed in particular by means of the nonequilibrium (nonergodic) states predicted in hydrodynamics of one-dimensional system of inelastic particles [1] as well as described in dynamics of 1D chemically reacted lattice model [2–5].Вивчаються стробоскопічно ущільнення вертикально вібруючих гранульованих матеріалів (високо дисипативного середовища, що складається з макроскопічних зерен, взаємодіючих контактно) з обмеженою геометрією. Можлива інтерпретація спостережуваної картини обговорюється, зокрема, з допомогою нерівноважних (неергодичних) станів, передбачених в гідродинаміці одновимірних систем нееластичних частинок [1] і описаних в динаміці одновимірної хімічно-активної граткової моделі [2–5]

Power-Law Inflation from the Rolling Tachyon

Modeling the potential by an inverse square law in terms of the tachyon field ($V(T)=\beta T^{-2}$) we find exact solution for spatially flat isotropic universe.We show that for $\beta>2\sqrt{3}/3$ the model undergoes power-law inflation. A way to construct other exact solutions is specified and exemplified.Comment: References added. Matches the version in print. To appear in PR

Aspects of Tachyonic Inflation with Exponential Potential

We consider issues related to tachyonic inflation with exponential potential. We find exact solution of evolution equations in the slow roll limit in FRW cosmology. We also carry out similar analysis in case of Brane assisted tachyonic inflation. We investigate the phase space behavior of the system and show that the dust like solution is a late time attractor. The difficulties associated with reheating in the tachyonic model are also indicated.Comment: New References added. To appear in Phys. Rev.

Soliton Spectrum of Integrable Models with Local Symmetries

The soliton spectrum (massive and massless) of a family of integrable models with local U(1) and U(1)\otimes U(1) symmetries is studied. These models represent relevant integrable deformations of SL(2,R) \otimes U(1)^{n-1} - WZW and SL(2,R) \otimes SL(2,R)\otimes U(1)^{n-2} - WZW models. Their massless solitons appears as specific topological solutions of the U(1) (or U(1)\otimes U(1)) - CFTs. The nonconformal analog of the GKO-coset formula is derived and used in the construction of the composite massive solitons of the ungauged integrable models.Comment: 44 pages, Latex, 1 eps fig, few misprints corrected. to appear in JHE

Polarization phenomena in open charm photoproduction processes

We analyze polarization effects in associative photoproduction of pseudoscalar ($\bar{D}$) charmed mesons in exclusive processes $\gamma+ N\to Y_c +\bar{D}$, $Y_c=\Lambda_c^+$, $\Sigma_c$. Circularly polarized photons induce nonzero polarization of the $Y_c$-hyperon with $x$- and $z$-components (in the reaction plane) and non vanishing asymmetries ${\cal A}_x$ and ${\cal A}_z$ for polarized nucleon target. These polarization observables can be predicted in model-independent way for exclusive $\bar{D}$-production processes in collinear kinematics. The T-even $Y_c$-polarization and asymmetries for non-collinear kinematics can be calculated in framework of an effective Lagrangian approach. The depolarization coefficients $D_{ab}$, characterizing the dependence of the $Y_c$-polarization on the nucleon polarization are also calculated.Comment: 36 pages 13 figure

D-brane Decay in Two-Dimensional String Theory

We consider unstable D0-branes of two dimensional string theory, described by the boundary state of Zamolodchikov and Zamolodchikov [hep-th/0101152] multiplied by the Neumann boundary state for the time coordinate $t$. In the dual description in terms of the $c=1$ matrix model, this D0-brane is described by a matrix eigenvalue on top of the upside down harmonic oscillator potential. As suggested by McGreevy and Verlinde [hep-th/0304224], an eigenvalue rolling down the potential describes D-brane decay. As the eigenvalue moves down the potential to the asymptotic region it can be described as a free relativistic fermion. Bosonizing this fermion we get a description of the state in terms of a coherent state of the tachyon field in the asymptotic region, up to a non-local linear field redefinition by an energy-dependent phase. This coherent state agrees with the exponential of the closed string one-point function on a disk with Sen's marginal boundary interaction for $t$ which describes D0-brane decay.Comment: 19 pages, harvmac, minor change

Tachyon Condensation, Boundary State and Noncommutative Solitons

We discuss the tachyon condensation in a single unstable D-brane in the framework of boundary state formulation. The boundary state in the background of the tachyon condensation and the NS B-field is explicitly constructed. We show in both commutative theory and noncommutative theory that the unstable D-branes behaves like an extended object and eventually reduces to the lower dimensional D-branes as the system approaches the infrared fixed point. We clarify the relationship between the commutative field theoretical description of the tachyon condensation and the noncommutative one.Comment: Revtex, 1 figure, References adde