New data on the morphology of permian gliding weigeltisaurid reptiles of Eastern Europe

New specimens of the Permian gliding reptile Rautiania from the Kul’chumovo-A locality (Russia, Orenburg Region) are described. The morphology of Rautiania strongly suggests adaptation for an obligatory arboreal mode of life and gliding flight (which are supported by the consolidated sacrum; free movements of the autopodial elements; specific manus morphology, typical of living arboreal vertebrates; strongly pneumatic structure of cranial bones and rodlike bones forming the frame of the gliding skin membrane; etc.). The homology of bones of the posterior wall of the temporal fenestra of weigeltisaurids is revised; according to the new concept, it consists of two dermal elements, the squamosal and quadratojugal. The outgrowths on the cranial bones of weigeltisaurids are of osteodermal nature. The diagnostic characters in the dental system of the genus Rautiania are considered, and the structure of the quadrate-articular complex of weigeltisaurids is described in detail for the first time. The original name of the family, Weigeltisauridae Kuhn, 1939, is restored. The appearance in the Late Permian of specialized gliding reptiles, such as the Weigeltisauridae, is accounted for by climactic conditions of terrestrial vertebrate communities in the pre-Triassic time, which resulted in the penetration of tetrapods into new adaptive zones, in particular, forest biotopes. The global distribution of weigeltisaurids is evidence of the widespread of high thin forests, the ecotopes most favorable for the appearance and subsequent dispersal of gliding animals, in the Late Permian and later on.     

Coprolite with Conchostracans from the Terminal Permian of Central Russia—Paleobiological and Stratigraphic Significance

The coprolite containing conchostracans from the terminal Permian Bykovka locality of Vyaznikovian tetrapod faunistic assemblage (the east of the Vladimir Region, Russia) are described for the first time. The most likely producers of such coprolites might be seymouriamorphs belonging to the genus Microphon, currently discovered in this locality. The composition of the conchostracan assemblage provides additional independent biostratigraphic confirmation of the highest position of Bykovka locality in the Permian interval of the Vyazniki section.     

Tearing instability of a force-free magnetic configuration in a collisionless plasma

The equilibrium and stability of a sheared force-free magnetic field in a collisionless plasma are investigated, and the main features of charged particle motion in such a field are analyzed. A steady solution is derived to the Vlasov-Maxwell equations for the charged particle distribution function that describes different equilibrium configurations. The tearing instability of the magnetic field configurations is studied both analytically and by particle-in-cell simulations.     

Feasibility of using laser ion accelerators in proton therapy

The feasibility of using laser plasma as a source of high-energy ions for the purposes of proton therapy is discussed. The proposal is based on the efficient ion acceleration observed in recent laboratory and numerical experiments on the interaction of high-power laser radiation with gaseous and solid targets. The specific dependence of proton energy losses in biological tissues (the Bragg peak) promotes the solution of one of the main problems of radiation therapy, namely, the irradiation of a malignant tumor with a sufficiently strong and homogeneous dose, ensuring that the irradiation of the surrounding healthy tissues and organs is minimal. In the scheme proposed, a beam of fast ions accelerated by a laser pulse can be integrated in the installations intended for proton therapy.     

Three-dimensional MHD simulations of forced magnetic reconnection

Results are presented from MHD simulations of three-dimensional flows of a high-conductivity plasma in the vicinity of a null point of a magnetic field. The excitation of an electric current at the boundary of the computation region results in self-consistent plasma flows and change in the structure of the magnetic field. Generally, in the vicinity of a null point, an MHD singularity arises that manifests itself in the formation of locally plane current sheets. It is shown that the current sheet can be oriented either along the separatrix surface of a magnetic configuration or perpendicular to it, except for axisymmetric configurations (or close to them), when the excitation of an electric current in the direction orthogonal to the separatrix surface does not lead to the formation of a current sheet.     

Ion acceleration in a dipole vortex in a laser plasma corona

Particle-in-cell simulations show that the inhomogeneity scale of the plasma produced in the interaction of high-power laser radiation with gas targets is of fundamental importance for ion acceleration. In a plasma slab with sharp boundaries, the quasistatic magnetic field and the associated electron vortex structure produced by fast electron beams both expand along the slab boundary in a direction perpendicular to the plasma density gradient, forming an extended region with a quasistatic electric field, in which the ions are accelerated. In a plasma with a smooth density distribution, the dipole magnetic field can propagate toward the lower plasma density in the propagation direction of the laser pulse. In this case, the electron density in an electric current filament at the axis of the magnetic dipole decreases to values at which the charge quasineutrality condition fails to hold. In electric fields generated by this process, the ions are accelerated to energies substantially higher than those characteristic of plasma configurations with sharp boundaries.     

Double-blind, placebo-controlled pilot and phase III study of activity of standardized Andrographis paniculata Herba Nees extract fixed combination (Kan jang) in the treatment of uncomplicated upper-respiratory tract infection.

Two randomized double-blind, placebo-controlled parallel group clinical trials were performed to investigate the effect of a standardized extract (SHA-10) of Andrographis paniculata fixed combination (Kan jang) in the treatment of uncomplicated upper-respiratory tract infections. 46 patients in the pilot study and 179 patients in the phase III study completed the study according to the protocol. Medication was taken three times daily for a minimum of 3 days and a maximum of 8 days for the pilot study, and for exactly three days in the phase III study. The primary outcome measures in the patients self-evaluation were: related to pain in the muscle, cough, throat symptoms, headache, nasal symptoms and eye symptoms and temperature. The physician's fixed score diagnosis was based mainly on sign/symptoms: ears, nose, oral cavity, lymph glands-tonsils and eyes. The total symptom score showed a tendency toward improvement in the pilot study (p = 0,08), while both the total symptom score and total diagnosis score showed highly significant improvement (p < or = 0.0006 resp. 0.003) in the verum group as compared with the placebo. In both studies throat symptoms/signs, were found to show the most significant improvement.     

Efficiency of ion acceleration by a relativistically strong laser pulse in an underdense plasma

A particle-in-cell simulation is used to investigate ion acceleration by a femtosecond laser pulse propagating in an underdense plasma slab. In plasma slabs with different thicknesses, the ions are found to be accelerated by different mechanisms. It is shown that, for laser pulse intensities in the range (5–10)×10¹⁹ W/cm², the ions are accelerated near the plasma-vacuum interface. __________ Translated from Fizika Plazmy, Vol. 27, No. 3, 2001, pp. 225–234. Original Russian Text Copyright ￠ 2001 by Kuznetsov, Esirkepov, Kamenets, Bulanov.     

Electron bunch acceleration in the wake wave breaking regime

Results are presented from theoretical analysis and 2D PIC simulations of electron acceleration in a breaking wake plasma wave generated by a short intense laser pulse during its interaction with a finite-length underdense plasma layer. The high energy electron energy spectrum and transverse emittance are obtained. It is shown that, for laser pulse lengths above the plasma wake wavelength, the wakefield-accelerated electrons are further accelerated by the electromagnetic wave. Published in Russian in Fizika Plazmy, 2006, Vol. 32, No. 4, pp. 291–310. The text was submitted by the authors in English.     

Interaction of electromagnetic waves with plasma in the radiation-dominated regime

A study is made of the main regimes of interaction of relativistically strong electromagnetic waves with plasma under conditions in which the radiation from particles plays a dominant role. The discussion is focused on such issues as the generation of short electromagnetic pulses in the interaction of laser light with clusters and highly efficient ion acceleration in a thin plasma slab under the action of the ponderomotive pressure of the wave. An approach is developed for generating superintense electromagnetic pulses by means of up-to-date laser devices.