Dust acoustic waves in three-dimensional complex plasmas with a similarity property

Dust acoustic waves in the bulk of a dust cloud in complex plasma of low-pressure gas discharge under microgravity conditions are considered. The complex plasma is assumed to conform to the ionization equation of state (IEOS) developed in our previous study. This equation implies the ionization similarity of plasmas. We find singular points of IEOS that determine the behavior of the sound velocity in different regions of the cloud. The fluid approach is utilized to deduce the wave equation that includes the neutral drag term. It is shown that the sound velocity is fully defined by the particle compressibility, which is calculated on the basis of the used IEOS. The sound velocities and damping rates calculated for different three-dimensional complex plasmas both in ac and dc discharges demonstrate a good correlation with experimental data that are within the limits of validity of the theory. The theory provides interpretation for the observed independence of the sound velocity on the coordinate and for a weak dependence on the particle diameter and gas pressure. Predictive estimates are made for the ongoing PK-4 experiment.

Structural Parameters for 10 Halo Globular Clusters in M33

In this paper, we present the properties of 10 halo globular clusters with luminosities $Lsimeq 5-7times 10^5{L_odot}$ in the Local Group galaxy M33 using the images of {it Hubble Space Telescope} Wide Field Planetary Camera 2 in the F555W and F814W bands. We obtained ellipticities, position angles and surface brightness profiles for them. In general, the ellipticities of M33 sample clusters are similar to those of M31 clusters. The structural and dynamical parameters are derived by fitting the profiles to three different models combined with mass-to-light ratios ($M/L$ values) from population-synthesis models. The structural parameters include core radii, concentration, half-light radii {bf and} central surface brightness. The dynamical parameters include the integrated cluster mass, integrated binding energy, central surface mass density {bf and} predicted line-of-sight velocity dispersion at the cluster center. The velocity dispersions of four clusters predicted here agree well with the observed dispersions by Larsen et al. The results here showed that the majority of the sample halo globular clusters are well fitted by King model as well as by Wilson model, and better than by Sersic model. In general, the properties of clusters in M33, M31 and the Milky Way fall in the same regions of parameter spaces. The tight correlations of cluster properties indicate a fundamental plane for clusters, which reflects some universal physical conditions and processes operating at the epoch of cluster formation.

Observations of dwarfs in nearby voids: implications for galaxy formation and evolution

The intermediate results of the ongoing study of deep samples of ~200 galaxies residing in nearby voids, are presented. Their properties are probed via optical spectroscopy, ugri surface photometry, and HI 21-cm line measurements, with emphasis on their evolutionary status. We derive directly the hydrogen mass M(HI), the ratio M(HI)/L_B and the evolutionary parameter gas-phase O/H. Their luminosities and integrated colours are used to derive stellar mass M(*) and the second evolutionary parameter -- gas mass-fraction f_g. The colours of the outer parts, typically representative of the galaxy oldest stellar population, are used to estimate the upper limits on time since the beginning of the main SF episode. We compare properties of void galaxies with those of the similar late-type galaxies in denser environments. Most of void galaxies show smaller O/H for their luminosity, in average by ~30%, indicating slower evolution. Besides, the fraction of ~10% of the whole void sample or ~30% of the least luminous void LSB dwarfs show the oxygen deficiency by a factor of 2--5. The majority of this group appear very gas-rich, with f_g ~(95-99)%, while their outer parts appear rather blue, indicating the time of onset of the main star-formation episode of less than 1-4 Gyr. Such unevolved LSBD galaxies appear not rare among the smallest void objects, but turned out practically missed to date due to the strong observational selection effects. Our results evidense for unusual evolutionary properties of the sizable fraction of void galaxies, and thus, pose the task of better modelling of dwarf galaxy formation and evolution in voids.

On applications of Maupertuis-Jacobi correspondence for Hamiltonians $F(x,|p|)$ in some 2-D stationary semiclassical problems

We make use of the Maupertuis -- Jacobi correspondence, well known in Classical Mechanics, to simplify 2-D asymptotic formulas based on Maslovs canonical operator, when constructing Lagrangian manifolds invariant with respect to phase flows for Hamiltonians of the form $F(x,|p|)$. As examples we consider Hamiltonians coming from the Schrodinger equation, the 2-D Dirac equation for graphene and linear water wave theory.

Measuring the evaluation and impact of scientific works and their authors

Problems for evaluation and impact of published scientific works and their authors are discussed. The role of citations in this process is pointed out. Different bibliometric indicators are reviewed in this connection and ways for generation of new bibliometric indices are given. The influence of different circumstances, like self-citations, number of authors, time dependence and publication types, on the evaluation and impact of scientific papers are considered. The repercussion of works citations and their content is investigated in this respect. Attention is paid also on implicit citations which are not covered by the modern bibliometrics but often are reflected in the peer reviews. Some aspects of the Web analogues of citations and new possibilities of the Internet resources in evaluating authors achievements are presented.

Relation lifting, with an application to the many-valued cover modality

We introduce basic notions and results about relation liftings on categories enriched in a commutative quantale. We derive two necessary and sufficient conditions for a 2-functor T to admit a functorial relation lifting: one is the existence of a distributive law of T over the powerset monad on categories, one is the preservation by T of exactness of certain squares. Both characterisations are generalisations of the classical results known for set functors: the first characterisation generalises the existence of a distributive law over the genuine powerset monad, the second generalises preservation of weak pullbacks. The results presented in this paper enable us to compute predicate liftings of endofunctors of, for example, generalised (ultra)metric spaces. We illustrate this by studying the coalgebraic cover modality in this setting.

Differences in the effects of turns and constrictions on the resistive response in current-biased superconducting wire after single photon absorption

We study how turns and constrictions affect the resistive response of the superconducting wire after instant in time and local in space heating, which models the absorption of the single photon by the wire. We find that the presence of constriction favors detection of photons of various energies but the presence of turn increases only ability to detect relatively low energy photons. The main reason is that in case of constriction the current density is increased over whole length and width of the constriction while in case of the turn the current density is enhanced only near the inner corner of the turn. It results in inhomogeneous Joule heating near the turn and worsens the conditions for appearance of the normal domain at relatively small currents when the high energy photons already could create normal domain in straight part of the wire. We also find that the amplitude of the voltage pulse depends on the place where the photon is absorbed. It is the smallest one when photon is absorbed near the turn and it is the largest one when photon is absorbed near the constriction. This effect comes from the difference in resistance of constriction and the turn in the normal state from the resistance of the rest of the wire.

Marriage of Electromagnetism and Gravity in Extended Space Model and Astrophysical Phenomena

The generalization of Einsteins special theory of relativity (SRT) is proposed. In this model the possibility of unification of scalar gravity and electromagnetism into a single united field is considered. Formally, the generalization of the SRT is that instead of (1+3)-dimensional Minkowski space the (1+4)-dimensional extension G is considered. As a fifth additional coordinate the interval S is used. This value is saved under the usual Lorentz transformations in Minkowski space M, but it changes when the transformations in the extended space G are used. We call this model the extended space model (ESM). From a physical point of view our expansion means that processes in which the rest mass of the particles changes are acceptable now. If the rest mass of a particle does not change and the physical quantities do not depend on an additional variable S, then the electromagnetic and gravitational fields exist independently of each other. But if the rest mass is variable and there is a dependence on S, then these two fields are combined into a single united field. In the extended space model a photon can have a nonzero mass and this mass can be either positive or negative. The gravitational effects such as the speed of escape, gravitational red shift and deflection of light can be analyzed in the frame of the extended space model. In this model all these gravitational effects can be found algebraically by the rotations in the (1+4) dimensional space. Now it becomes possible to predict some future results of visible size of super massive objects in our Universe due to new stage of experimental astronomy development in the Radio Astron Project and analyze phenomena of the star V838 Monocerotis explosion as possible Local Big Bang (LBB).

Proceedings Eighth Workshop on Model-Based Testing

This volume contains the proceedings of the Eighth Workshop on Model-Based Testing (MBT 2013), which was held on March 17, 2013 in Rome, Italy, as a satellite event of the European Joint Conferences on Theory and Practice of Software, ETAPS 2013. The workshop is devoted to model-based testing of both software and hardware. Model-based testing uses models describing the required behavior of the system under consideration to guide such efforts as test selection and test results evaluation. Testing validates the real system behavior against models and checks that the implementation conforms to them, but is capable also to find errors in the models themselves. The first MBT workshop was held in 2004, in Barcelona. At that time MBT already had become a hot topic, but the MBT workshop was the first event devoted mostly to this domain. Since that time the area has generated enormous scientific interest, and today there are several specialized workshops and more broad conferences on software and hardware design and quality assurance covering model based testing. MBT has become one of the most powerful system analysis tools, one of the latest cutting-edge topics related is applying MBT in security analysis and testing. MBT workshop tries to keep up with current trends.

HI shells in the Leiden/Argentina/Bonn HI survey

We analyse the all-sky Leiden/Argentina/Bonn HI survey, where we identify shells belonging to the Milky Way. We used an identification method based on the search of continuous regions of a low brightness temperature that are compatible with given properties of HI shells. We found 333 shells in the whole Galaxy. The size distribution of shells in the outer Galaxy is fitted by a power law with the coefficient of 2.6 corresponding to the index 1.8 in the distribution of energy sources. Their surface density decreases exponentially with a scale length of 2.8 kpc. The surface density of shells with radii >= 100 pc in the solar neighbourhood is around 4 per kpc^2 and the 2D porosity is approximately 0.7.