Regular modes in rotating stars

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray dynamics to build an asymptotic theory for the subset of regular modes which are the easiest to observe and identify. Comparisons with 2D numerical simulations of oscillations in polytropic stars show that both the frequency and amplitude distributions of these modes can accurately be described by an asymptotic theory for almost all rotation rates. The spectra are mainly characterized by two quantum numbers; their extraction from observed spectra should enable one to obtain information about stellar interiors.Comment: 5 pages, 4 figures, discussion adde

ВИДОВОЙ СОСТАВ И ТАКСОНОМИЧЕСКАЯ СТРУКТУРА ЦИСТООБРАЗУЮЩИХ НЕМАТОД КУЛЬТУРНЫХ И ПРИРОДНЫХ ФИТОЦЕНОЗОВ УКРАИНЫ

The species structure, morphological peculiarities and economic importance of the dominant cyst nematodes from cultural and natural phytocenosis of Ukraine are analyzed.Проанализирован видовой состав, морфологические особенности и экономическое значение доминирующих цистообразующих нематод культурных и природных фитоценозов Украины

Integrative Modeling of Electrical Properties of Pacemaker Cardiac Cells

This work represents modeling of electrical properties of pacemaker (sinus) cardiac cells. Special attention is paid to electrical potential arising from transmembrane current of Na{+}, K{+} and Ca{2+} ions. This potential is calculated using the NaCaX model. In this respect, molar concentration of ions in the intercellular space which is calculated on the basis of the GENTEX model is essential. Combined use of two different models allows referring this approach to integrative modeling

Phonon-Coupled Electron Tunneling in Two and Three-Dimensional Tunneling Configurations

We treat a tunneling electron coupled to acoustical phonons through a realistic electron phonon interaction: deformation potential and piezoelectric, in two or three-dimensional tunneling configurations. Making use of slowness of the phonon system compared to electron tunneling, and using a Green function method for imaginary time, we are able to calculate the change in the transition probability due to the coupling to phonons. It is shown using standard renormalization procedure that, contrary to the one-dimensional case, second order perturbation theory is sufficient in order to treat the deformation potential coupling, which leads to a small correction to the transmission coefficient prefactor. In the case of piezoelectric coupling, which is found to be closely related to the piezoelectric polaron problem, vertex corrections need to be considered. Summing leading logarithmic terms, we show that the piezoelectric coupling leads to a significant change of the transmission coefficient.Comment: 17 pages, 4 figure

Influence of the composition on the thermoelectric and electro-physical properties of Ge-Sb-Te thin films for phase change memory application

Influence of the composition variation along the quasi-binary line GeTe-Sb2Te3 on the thermoelectric and electro-physical properties of thin films was investigated. GST amorphous thin films have high Seebeck coefficients, which drops nearly on the order of magnitude after the crystallization. Temperature dependences of the resistivities were studied, and it was determined that crystallization temperature increases with moving along the quasi-binary line GeTe-Sb2Te3 from GeSb4Te7 to GeSb2Te4, and then to Ge2Sb2Te5, while the phase transition temperature range decreases. Current-voltage characteristics of amorphous thin films have three voltage ranges with different dependencies due to the different mechanisms of charge carrier transport

Effects of broadening and electron overheating in tunnel structures based on metallic clusters

We study the influence of energy levels broadening and electron subsystem overheating in island electrode (cluster) on current-voltage characteristics of three-electrode structure. A calculation scheme for broadening effect in one-dimensional case is suggested. Estimation of broadening is performed for electron levels in disc-like and spherical gold clusters. Within the two-temperature model of metallic cluster and by using a size dependence of the Debye frequency the effective electron temperature as a function of bias voltage is found approximately. We suggest that the effects of broadening and electron overheating are responsible for the strong smoothing of current-voltage curves, which is observed experimentally at low temperatures in structures based on clusters consisting of accountable number of atoms.Comment: 8 pages, 5 figure

Identification of extra neutral gauge bosons at the International Linear Collider

Heavy neutral gauge bosons, Z's, are predicted by many theoretical schemes of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible that Z's are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z' exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the foreseeable sensitivity to Z's of fermion-pair production cross sections at an e^+e^- linear collider, especially as regards the potential of distinguishing different Z' models once such deviations are observed. Specifically, we assess the discovery and identification reaches on Z' gauge bosons pertinent to the E_6, LR, ALR and SSM classes of models, that should be attained at the planned International Linear Collider (ILC). With the high experimental accuracies expected at the ILC, the discovery and the identification reaches on the Z' models under consideration could be increased substantially. In particular, the identification among the different models could be achieved for values of Z' masses in the discovery (but beyond the identification) reach of the LHC. An important role in enhancing such reaches is played by the electron (and possibly the positron) longitudinally polarized beams. Also, although the purely leptonic processes are experimentally cleaner, the measurements of c- and b-quark pair production cross sections are found to carry important, and complementary, information on these searches.Comment: 21 page

A smooth bouncing cosmology with scale invariant spectrum

We present a bouncing cosmology which evolves from the contracting to the expanding phase in a smooth way, without developing instabilities or pathologies and remaining in the regime of validity of 4d effective field theory. A nearly scale invariant spectrum of perturbations is generated during the contracting phase by an isocurvature scalar with a negative exponential potential and then converted to adiabatic. The model predicts a slightly blue spectrum, n_S >~ 1, no observable gravitational waves and a high (but model dependent) level of non-Gaussianities with local shape. The model represents an explicit and predictive alternative to inflation, although, at present, it is clearly less compelling.Comment: 20 pages, 1 fig. v2: references added, JCAP published versio

Evaluation of Sorption Materials Derived from Aquatic Vegetation

Работа посвящена изучению возможности использования камыша озерного ( Scirpus lacustris ) и рогоза узколистного ( Typha angustifolia ) для получения угольных сорбентов. Исследуемый метод получения углей - гидротермальное ожижение. Отмечено среднее содержание углерода в сырье (около 45%). Установлен рост содержания углерода в биомассе после гидротермального ожижения на 15%, конечное содержание углерода составило 60%. Выход угольного остатка в среднем составил 30%. Сорбционная емкость оценивалась по 3 веществам: метиленовый синий, йод (водный раствор), фенол. Отмечено относительно высокое значение сорбционной ёмкости по метиленовому синему для угля из камыша (17,8 мг/г), йоду для угля из рогоза (29,7 мг/г). Отмечено невысокое значение сорбционной емкости по фенолу для обоих углей. Предложено использование исследуемых углей в качестве альтернативы дешевым сорбентам.The work is devoted to studying the possibility of using lake cane (Scirpus lacustris) and narrow-leaved cattail (Typha angustifolia) to produce carbon sorbents. The investigated method of hydrochar production is hydrothermal liquefaction. The average carbon content in the raw material (about 45%) was observed. The carbon content of biomass after hydrothermal liquefaction was found to increase by 15% and the final carbon content was 60%. The yield of carbon residue averaged 30%. Sorption capacity was evaluated for 3 substances: methylene blue, iodine (aqueous solution), phenol. A relatively high value of sorption capacity for methylene blue for hydrochar from cane (17.8 mg/g), iodine for hydrochar from cattail (29.7 mg/g) was noted. The low value of sorption capacity for phenol for both hydrochars was noted. It is suggested to use the studied hydrochars as an alternative to cheap sorbents