Mixing of fermion fields of opposite parities and baryon resonances

We consider a loop mixing of two fermion fields of opposite parities whereas the parity is conserved in a Lagrangian. Such kind of mixing is specific for fermions and has no analogy in boson case. Possible applications of this effect may be related with physics of baryon resonances. The obtained matrix propagator defines a pair of unitary partial amplitudes which describe the production of resonances of spin $J$ and different parity ${1/2}^{\pm}$ or ${3/2}^{\pm}$. The use of our amplitudes for joint description of $\pi N$ partial waves $P_{13}$ and $D_{13}$ shows that the discussed effect is clearly seen in these partial waves as the specific form of interference between resonance and background. Another interesting application of this effect may be a pair of partial waves $S_{11}$ and $P_{11}$ where the picture is more complicated due to presence of several resonance states.Comment: 22 pages, 6 figures, more detailed comparison with \pi N PW

Fermion resonance in quantum field theory

We derive accurately the fermion resonance propagator by means of Dyson summation of the self-energy contribution. It turns out that the relativistic fermion resonance differs essentially from its boson analog.Comment: 8 pages, 2 figures, revtex4 class; references added, style correction

The Rarita--Schwinger field: renormalization and phenomenology

We discuss renormalization of propagator of interacting Rarita--Schwinger field. Spin-3/2 contribution after renormalization takes usual resonance form. For non-leading spin-1/2 terms we found procedure, which guarantees absence of poles in energy plane. The obtained renormalized propagator has one free parameter and is a straight generalization of the famous free propagator of Moldauer and Case. Application of this propagator for production of $\Delta^{++}(1232)$ in \pi^{+}\particle{p}\to \pi^{+}\particle{p} leads to good description of total cross-section and to reasonable agreement with results of partial wave analysis.Comment: 19 pages, 3 figures, revtex4; misprints, min editorial change

Design of semantic information broker for localized computing environments in the internet of things

Emerging communication technologies of the Internet of Things (IoT) make all the devices of a spatial-limited physical computing environment locally interconnected as well as connected to the Internet. Software agents running on devices make the latter “smart objects” that are visible in our daily lives as real participating entities. Based on the M3 architecture for smart spaces, we consider the problem of creating a smart space deploying a Semantic Information Broker (SIB) in a localized IoT-environment. SIB supports agent interaction in the smart space via sharing and self-generating information and its semantics. This paper proposes a renewed SIB design with increased extensibility, dependability, and portability. The research done is a step towards an efficient open interoperability platform for the smart space application development

Electron transport and optical properties of shallow GaAs/InGaAs/GaAs quantum wells with a thin central AlAs barrier

Shallow GaAs/InGaAs/GaAs quantum well structures with and without a three monolayer thick AlAs central barrier have been investigated for different well widths and Si doping levels. The transport parameters are determined by resistivity measurements in the temperature range 4-300 K and magnetotransport in magnetic fields up to 12 T. The (subband) carrier concentrations and mobilities are extracted from the Hall data and Shubnikov-de Haas oscillations. We find that the transport parameters are strongly affected by the insertion of the AlAs central barrier. Photoluminescence spectra, measured at 77 K, show an increase of the transition energies upon insertion of the barrier. The transport and optical data are analyzed with help of self-consistent calculations of the subband structure and envelope wave functions. Insertion of the AlAs central barrier changes the spatial distribution of the electron wave functions and leads to the formation of hybrid states, i.e. states which extend over the InGaAs and the delta-doped layer quantum wells.Comment: 14 pages, pdf fil

Simulation of Comet Impact and Survivability of Organic Compounds

Comets have long been proposed as a potential means for the transport of complex organic compounds to early Earth. For this to be a viable mechanism, a significant fraction of organic compounds must survive the high temperatures due to impact. We have undertaken three-dimensional numerical simulations to track the thermodynamic state of a comet during oblique impacts. The comet was modeled as a 1-km water-ice sphere impacting a basalt plane at 11.2 km/s; impact angles of 15{sup o} (from horizontal), 30{sup o}, 45{sup o}, 65{sup o}, and 90{sup o} (normal impact) were examined. The survival of organic cometary material, modeled as water ice for simplicity, was calculated using three criteria: (1) peak temperatures, (2) the thermodynamic phase of H{sub 2}O, and (3) final temperature upon isentropic unloading. For impact angles greater than or equal to 30{sup o}, no organic material is expected to survive the impact. For the 15{sup o} impact, most of the material survives the initial impact and significant fractions (55%, 25%, and 44%, respectively) satisfy each survival criterion at 1 second. Heating due to deceleration, in addition to shock heating, plays a role in the heating of the cometary material for nonnormal impacts. This effect is more noticeable for more oblique impacts, resulting in significant deviations from estimates using scaling of normal impacts. The deceleration heating of the material at late times requires further modeling of breakup and mixing

Политическая аккомодация культурных различий в индустриально развитых обществах

The notion of "political accommodation" applied to the theory and practice of managing cultural diversity could enrich the Russian academic dictionary. Liberal democratic states invented specific mechanisms for political accommodation of cultural differences. Thanks to these mechanisms, the part of the population of a democratic state that is not ready to dissolve into the ethnocultural majority is more or less protected. The law not only prohibits forced assimilation, but also contains a number of norms that allow ethnocultural minorities to maintain their distinctiveness by passing it on from generation to generation. However, this is the case in liberal democracies with a long history. In states that emerged as a result of the collapse of two multinational policies - Yugoslavia and the USSR - the situation sometimes looks quite specific. They take more active measures for cultural homogenization than in previous years. As for Russia, in recent years there have been symptomatic changes in the sphere of ethno-cultural policy, which, although with a number of reservations, can be described in terms of "nationalization"

Rarita--Schwinger field and multi-component wave equation

We suggest simple method to solve wave equation for Rarita--Schwinger field without additional constraints. This method based on use of off-shell projection operators allows to diagonalize spin-1/2 sector of the field.Comment: 6 page

Measurement and analysis of needle penetration forces in industrial high-speed sewing machine

The industrial manufacturing of sewn products has always been one of the critical processes of the textile chain concerning quality assurance. Assuring the appropriate set-up and operation of all the machines, and thus the final seam quality, is a very complex task. Traditionally, this task is accomplished through empirical methods, with the machine setting and quality control relying on the skills of operators and technicians. This work presents an approach to a more knowledge-based and integrated process planning and control. A system was developed to measure and analyze the most important mechanical effects occurring during high-speed sewing. The paper will focus mainly on the measurement and evaluation of needle penetration and withdrawal force. After an overview of the system, the most important experimental results obtained in a series of experiments will be described