Investigation of Non-Stable Processes in Close Binary Ry Scuti

We present results of reanalysis of old electrophotometric data of early type close binary system RY Scuti obtained at the Abastumani Astrophysical Observatory, Georgia, during 1972-1990 years and at the Maidanak Observatory, Uzbekistan, during 1979-1991 years. It is revealed non-stable processes in RY Sct from period to period, from month to month and from year to year. This variation consists from the hundredths up to the tenths of a magnitude. Furthermore, periodical changes in the system's light are displayed near the first maximum on timescales of a few years. That is of great interest with regard to some similar variations seen in luminous blue variable (LBV) stars. This also could be closely related to the question of why RY Sct ejected its nebula.Comment: 11 pages, 6 figures, 2 table

Surface alignment and anchoring transitions in nematic lyotropic chromonic liquid crystal

The surface alignment of lyotropic chromonic liquid crystals (LCLCs) can be not only planar (tangential) but also homeotropic, with self-assembled aggregates perpendicular to the substrate, as demonstrated by mapping optical retardation and by three-dimensional imaging of the director field. With time, the homeotropic nematic undergoes a transition into a tangential state. The anchoring transition is discontinuous and can be described by a double-well anchoring potential with two minima corresponding to tangential and homeotropic orientation.Comment: Accepted for publication in Phys. Rev. Lett. (Accepted Wednesday Jun 02, 2010

First fossil species of ship-timber beetles (Coleoptera, Lymexylidae) from Eocene Rovno amber (Ukraine)

A new lymexylid fossil species, †Raractocetus sverlilo Nazarenko, Perkovsky & Yamamoto, sp. nov., is described from late Eocene Rovno amber of Ukraine. This new species is similar to species of the recent genera Atractocerus Palisot de Beauvois and Raractocetus Kurosawa in the ship-timber beetle subfamily Atractocerinae, but differs in pronotal and elytral features. Notably, the new species is one of the smallest atractocerines known to date. This is the first member of the family Lymexylidae found in Rovno amber. Our finding sheds further light on the paleodiversity of atractocerine beetles, highlighting a peculiar distribution during the Eocene. Only one extant atractocerine specimen has been reported from Europe (Greece), while three species from Eocene European amber forests with equable climate are known now, including two species from the otherwise tropical genus Raractocetus. Our finding of the Raractocetus beetle from Rovno amber is of significant biogeographically because it indicates the wide distribution of the genus in the Eocene European amber forests

Influence of parameters of delayed asphalt coking process on yield and quality of liquid and solid-phase products

Paper studies the effect of excess pressure during delayed coking of asphalt, obtained by propane deasphaltization of tar, on yield and physical and chemical properties of hydrocarbon fuels' components and solid-phase product – petroleum coke. Asphalt was coked at a temperature of 500 °C and excess pressure of 0.15-0.35 MPa in a laboratory unit for delayed coking of periodic action. Physical and chemical properties of raw materials and components of light (gasoline), medium (light gasoil), and heavy (heavy gasoil) distillates obtained during experimental study were determined: density, viscosity, coking ability, sulfur content, iodine number, pour points, flash points, fluidity loss and fractional composition. Quantitative group hydrocarbon and microelement compositions and properties of obtained samples of petroleum coke (humidity, ash content, volatiles' yield, sulfur content, etc.) were also studied. Comparative assessment of their quality is given in accordance with requirements of GOST 22898-78 “Low-sulfur petroleum coke. Specifications”. In addition, patterns of changes in excess coking pressure on yield and quality indicators of distillate products and petroleum coke were revealed. With an increase in excess pressure of coking process from 0.15 to 0.35 MPa, content of paraffin-naphthenic hydrocarbons in light and heavy gasoils of delayed coking  decreases. Common pattern in asphalt coking is an increase in yield of coke and hydrocarbon gas with an increase in excess pressure from 0.15 to 0.35 MPa

Parameters of the Effective Singlet-Triplet Model for Band Structure of High-TcT_c Cuprates by Different Approaches

The present paper covers the problem of parameters determination for High-$T_c$ superconductive copper oxides. Different approaches, {\it ab initio} LDA and LDA+U calculations and Generalized Tight-Binding (GTB) method for strongly correlated electron systems, are used to calculate hopping and exchange parameters of the effective singlet-triplet model for $CuO_2$-layer. The resulting parameters are in remarkably good agreement with each other and with parameters extracted from experiment. This set of parameters is proposed for proper quantitative description of physics of hole doped High-$T_c$ cuprates in the framework of effective models.Comment: PACS 74.72.h; 74.20.z; 74.25.Jb; 31.15.A

Hormonal parameters and embryological outcomes of in vitro fertilisation/intra cytoplasmic sperm injection cycles in women using dydrogesterone for the prevention of premature luteinizing hormone surge during ovarian stimulation

Aim. To evaluate the hormonal parameters and embryological outcomes of an ovarian stimulation protocol using dydrogesterone to prevent the premature LH surge in IVF/ICSI programmes. Materials and methods. A prospective study randomised, including 79 women with normal ovarian reserve undergoing ovarian stimulation for IVF/ICSI with recombinant FSH (rFSH) from Day 2 or 3 of the menstrual cycle. To prevent the premature LH surge, participants in Group 1 (n=38) received oral dydrogesterone 20 mg/day from the start of ovarian stimulation until the day of ovulation trigger administration. Participants in Group 2 (n=41) received a GnRH antagonist. We evaluated the starting and total dose of gonadotropins, duration of stimulation, serum levels of LH, oestradiol and progesterone on Day 1 and 6 of stimulation and the day of trigger administration, number of retrieved and mature oocytes, fertilization rate, and the number of blastocysts and cryopreserved embryos. Results. There were no significant differences in most hormonal parameters, characteristics of the ovarian stimulation and embryological outcomes between the two groups. Serum levels of progesterone in the dydrogesterone arm were higher than in the GnRH antagonist arm (2.3 nmol/l [2.03.4] vs 1.5 [1.02.4] nmol/l; p=0.026), but without any impact on the embryological outcomes. Conclusion. Prevention of premature LH surge in ovarian stimulation cycles using oral dydrogesterone may represent a convenient alternative to the conventional use of GnRH antagonists, reducing the number of required injections and potentially increasing the convenience in patients who are not planning a fresh embryo transfer

Single Spin Superconductivity: Formulation and Ginzburg-Landau Theory

We describe a novel superconducting phase that arises due to a pairing instability of the half-metallic antiferromagnetic (HM AFM) normal state. This single spin superconducting (SSS) phase contains broken time reversal symmetry in addition to broken gauge symmetry, the former due to the underlying magnetic order in the normal state. A classification of normal state symmetries leads to the conclusion that the HM AFM normal phase whose point group contains the inversion operator contains the least symmetry possible which still allows for a zero momentum pairing instability. The Ginzburg-Landau free energy for the superconducting order parameter is constructed consistent with the symmetry of the normal phase, electromagnetic gauge invariance and the crystallographic point group symmetry including inversion. For cubic, hexagonal and tetragonal point groups, the possible symmetries of the superconducting phase are classified, and the free energy is used to construct a generalized phase diagram. We identify the leading candidate out of the possible SSS phases for each point group. The symmetry of the superconducting phase is used to determine the cases where the gap function has generic zeros (point or line nodes) on the Fermi surface. Such nodes always occur, hence thermodynamic properties will have power-law behavior at low temperature.Comment: 39 pages, RevTeX, 4 PostScript figures included, submitted to Phys. Rev.