Vanishing Viscosity Approach to the Compressible Euler Equations for Transonic Nozzle and Spherically Symmetric Flows

We are concerned with globally defined entropy solutions to the Euler equations for compressible fluid flows in transonic nozzles with general cross-sectional areas. Such nozzles include the de Laval nozzles and other more general nozzles whose cross-sectional area functions are allowed at the nozzle ends to be either zero (closed ends) or infinity (unbounded ends). To achieve this, in this paper, we develop a vanishing viscosity method to construct globally defined approximate solutions and then establish essential uniform estimates in weighted $L^p$ norms for the whole range of physical adiabatic exponents $\gamma\in (1, \infty)$, so that the viscosity approximate solutions satisfy the general $L^p$ compensated compactness framework. The viscosity method is designed to incorporate artificial viscosity terms with the natural Dirichlet boundary conditions to ensure the uniform estimates. Then such estimates lead to both the convergence of the approximate solutions and the existence theory of globally defined finite-energy entropy solutions to the Euler equations for transonic flows that may have different end-states in the class of nozzles with general cross-sectional areas for all $\gamma\in (1, \infty)$. The approach and techniques developed here apply to other problems with similar difficulties. In particular, we successfully apply them to construct globally defined spherically symmetric entropy solutions to the Euler equations for all $\gamma\in (1, \infty)$.Comment: 32 page

A novel minimal in vitro system for analyzing HIV-1 Gag mediated budding

A biomimetic minimalist model membrane was used to study the mechanism and kinetics of cell-free in vitro HIV-1 Gag budding from a giant unilamellar vesicle (GUV). Real time interaction of Gag, RNA and lipid leading to the formation of mini-vesicles was measured using confocal microscopy. Gag forms resolution limited punctae on the GUV lipid membrane. Introduction of the Gag and urea to a GUV solution containing RNA led to the budding of mini-vesicles on the inside surface of the GUV. The GUV diameter showed a linear decrease in time due to bud formation. Both bud formation and decrease in GUV size were proportional to Gag concentration. In the absence of RNA, addition of urea to GUVs incubated with Gag also resulted in subvesicle formation but exterior to the surface. These observations suggest the possibility that clustering of GAG proteins leads to membrane invagination even in the absence of host cell proteins. The method presented here is promising, and allows for systematic study of the dynamics of assembly of immature HIV and help classify the hierarchy of factors that impact the Gag protein initiated assembly of retroviruses such as HIV.Comment: 27 pages, 9 Figures and 0 Table

Leveraging Diversity in Online Interactions

This paper addresses the issue of connecting people online to help them find support with their day-to-day problems. We make use of declarative norms for mediating online interactions, and we specifically focus on the issue of leveraging diversity when connecting people. We run pilots at different university sites, and the results show relative success in the diversity of the selected profiles, backed by high user satisfaction

Pengukuran Resiko Teknologi Informasi (Ti) dengan Metode Octave-s

Article presented a measurement of Information Technology (IT) risk levels and identify security practices whichwere suitable in the risk overcoming, as noted in PTNL. Company was also expected to be more alert to the risk impactsof information technology which might occur in PTNL. Analytical method used was OCTAVE-S method. This method wasused in a risk measurement of information technology risk, with some steps which had important roles in searching for themeasurement results effectively and efficiently, which were applied in PTNL. The results which will be achieved were to giveoverall results of risk measurement occurred at the company, either the plus or minus, and provide recommendations whichare expected to solve and correct the minus or problems which occurred in PTNL. Conclusion states that the risk measurementof information technology performed in PTNI has successfully minimized the risks that can threaten the company's security

Proton-Antiproton Annihilation in Baryonium

A possible interpretation of the near-threshold enhancement in the $(p\bar{p})$-mass spectrum in $J/\psi{\to}\gamma p{\bar p}$ is the of existence of a narrow baryonium resonance X(1860). Mesonic decays of the $(p\bar{p})$-bound state X(1860) due to the nucleon-antinucleon annihilation are investigated in this paper. Mesonic coherent states with fixed $G$-parity and $P$-parity have been constructed . The Amado-Cannata-Dedoder-Locher-Shao formulation(Phys Rev Lett. {\bf 72}, 970 (1994)) is extended to the decays of the X(1860). By this method, the branch-fraction ratios of $Br(X\to \eta 4\pi)$, $Br(X\to \eta 2\pi)$ and $Br(X\to 3\eta)$ are calculated. It is shown that if the X(1860) is a bound state of $(p\bar{p})$, the decay channel ($X\to \eta 4\pi)$ is favored over $(X\to \eta 2\pi)$. In this way, we develop criteria for distinguishing the baryonium interpretation for the near-threshold enhancement effects in $(p\bar{p})$-mass spectrum in $J/\psi{\to}\gamma p{\bar p}$ from other possibilities. Experimental checks are expected. An intuitive picture for our results is discussed.Comment: 19 pages, 3 figure

Half-metallic ferromagnetism and structural stability of zincblende phases of the transition-metal chalcogenides

An accurate density-functional method is used to study systematically half-metallic ferromagnetism and stability of zincblende phases of 3d-transition-metal chalcogenides. The zincblende CrTe, CrSe, and VTe phases are found to be excellent half-metallic ferromagnets with large half-metallic gaps (up to 0.88 eV). They are mechanically stable and approximately 0.31-0.53 eV per formula unit higher in total energy than the corresponding nickel-arsenide ground-state phases, and therefore would be grown epitaxially in the form of films and layers thick enough for spintronic applications.Comment: 4 pages with 4 figures include

Charged particles in a rotating magnetic field

We study the valence electron of an alkaline atom or a general charged particle with arbitrary spin and with magnetic moment moving in a rotating magnetic field. By using a time-dependent unitary transformation, the Schr\"odinger equation with the time-dependent Hamiltonian can be reduced to a Schr\"odinger-like equation with a time-independent effective Hamiltonian. Eigenstates of the effective Hamiltonian correspond to cyclic solutions of the original Schr\"odinger equation. The nonadiabatic geometric phase of a cyclic solution can be expressed in terms of the expectation value of the component of the total angular momentum along the rotating axis, regardless of whether the solution is explicitly available. For the alkaline atomic electron and a strong magnetic field, the eigenvalue problem of the effective Hamiltonian is completely solved, and the geometric phase turns out to be a linear combination of two solid angles. For a weak magnetic field, the same problem is solved partly. For a general charged particle, the problem is solved approximately in a slowly rotating magnetic field, and the geometric phases are also calculated.Comment: REVTeX, 13 pages, no figure. There are two minor errors in the published version due to incorrect editing by the publisher. The "spin-1" in Sec. I and the "spin 1" in Sec. II below Eq. (2c) should both be changed to "spin" or "spin angular momentum". The preferred E-mail for correspondence is [email protected] or [email protected]

Spherical-box approach for resonances in presence of Coulomb interaction

The spherical-box approach is extended to calculate the resonance parameters and the real part of the wave function for single particle resonances in a potential containing the long-range Coulomb interaction. A model potential is taken to demonstrate the ability and accuracy of this approach. The calculated resonance parameters are compared with available results from other methods. It is shown that in the presence of the Coulomb interaction, the spherical-box approach works well for not so broad resonances. In particular, for very narrow resonances, the present method gives resonance parameters in a very high precision.Comment: 10 pages, 5 EPS figures; to be published in J. Phys.

KLJUČNI ČIMBENICI U UROĐENOM IMUNOLOŠKOM PREPOZNAVANJU VIRUSNE INFEKCIJE U SISAVACA I RIBA

Viral infection of mammalian cells activates an innate antiviral immune response characterized by production of interferon and subsequent enhanced transcription of interferon–stimulated genes important for antiviral defense. Cells recognize viral infection through various pathogen–associated molecular patterns, of which dsRNA seems to be the most important. In mammals, several gene products are important in recognition of dsRNA: RIG–I, TLR3, PKR and mda–5. Recent research proved that fish possess most of the key elements in recognition of viral infection which indicates that these mechanisms are very similar and evolutionary conserved in vertebrates.Virusna infekcija u stanicama sisavaca potiče urođeni odgovor karakteriziran proizvodnjom interferona i posljedičnom pojačanom transkripcijom interferonima stimuliranih gena, bitnih u obrani organizma od virusa. Stanice prepoznaju virusnu infekciju preko određenih molekularnih uzoraka povezanih s patogenima, od kojih je najvažnija dvolančana RNK. U organizmu sisavaca ključnu ulogu u prepoznavanju dvolančane RNK ima nekoliko gena: RIG–I, TLR3, PKR i mda–5. Dosadašnja su istra‘ivanja pokazala da ribe posjeduju većinu ključnih elemenata zaduženih za prepoznavanje virusne infekcije, što upućuje na veliku sličnost i evolucijsku očuvanost spomenutih mehanizama

New effective interactions in RMF theory with non-linear terms and density-dependent meson-nucleon coupling

New parameter sets for the Lagrangian density in the relativistic mean field (RMF) theory, PK1 with nonlinear sigma- and omega-meson self-coupling, PK1R with nonlinear sigma-, omega- and rho-meson self-coupling and PKDD with the density-dependent meson-nucleon coupling, are proposed. They are able to provide an excellent description not only for the properties of nuclear matter but also for the nuclei in and far from the valley of beta-stability. For the first time in the parametrization of the RMF Lagrangian density, the center-of-mass correction is treated by a microscopic way, which is essential to unify the description of nuclei from light to heavy regions with one effective interaction.Comment: 22 pages, 16 EPS figures, RevTeX