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We investigate the deformation dependence of the moment of inertia $\cal J$ for light nuclei $^{24}$Mg and $^{20}$Ne and find regimes where $\cal J$ decreases with increasing the axial quadrupole deformation $\beta$, at variance with the generally expected increasing trend. The study is based on quadrupole constrained calculations using three cranking approaches for $\cal J$ (Inglis-Belyaev, Thouless-Valatin, adiabatic time-dependent Hartree-Fock) and representative set of Skyrme forces (SVbas, SkM* and SLy6). The calculations cover a wide deformation range 0 $< \beta < $ 1.2. The anomalous regime with $d{\cal J}/d\beta, Comment: 12 pages, 9 figures

Background: Inelastic proton scattering at energies of a few hundred MeV and very-forward angles including $0^\circ$ has been established as a tool to study electric-dipole strength distributions in nuclei. The present work reports a systematic investigation of the chain of stable even-mass Nd isotopes representing a transition from spherical to quadrupole-deformed nuclei. Purpose: Extraction of the equivalent photo-absorption cross sections and analysis of their fine structure in the energy region of the IsoVector Giant Dipole Resonance (IVGDR). Method: Proton inelastic scattering reactions of 200 MeV protons were measured at iThemba LABS in Cape Town, South Africa. The scattering products were momentum-analysed by the K600 magnetic spectrometer positioned at $\theta_{\mathrm{Lab}}=0^\circ$. Using dispersion-matching techniques, energy resolutions of $\Delta E \approx 40 - 50$ keV were obtained. After subtraction of background and contributions from other multipoles, the spectra were converted to photo-absorption cross sections using the equivalent virtual-photon method. Results: Wavelet-analysis techniques are used to extract characteristic energy scales of the fine structure of the IVGDR from the experimental data. Comparisons with the Quasiparticle-Phonon Model (QPM) and Skyrme Separable Random Phase Approximation (SSRPA) predictions provide insight into the role of different giant resonance damping mechanisms. Conclusions: Fine structure is observed even for the most deformed nuclei studied. Fragmentation of the one particle-one hole ($1p1h$) strength seems to be the main source of fine structure in both spherical and deformed nuclei. Some impact of the spreading due to coupling of the two particle-two hole ($2p2h$) states to the $1p1h$ doorway states is seen in the spherical/transitional nuclei, where calculations beyond the $1p1h$ level are available., Comment: 17 pages, 17 figures; Minor changes made such as those clarifying the descriptions of the analysis procedure, but the results are unchanged. The current version was accepted for publication by PRC on 7 December 2020

Individual low-energy E1 toroidal and compressional states (TS and CS) produced by the convective nuclear current ${\bf j}_{\rm c}$ were recently predicted for $^{24}$Mg in the framework of quasiparticle random-phase-approximation (QRPA) with Skyrme forces. In the present QRPA study with Skyrme parametrization SLy6, we explore in more detail properties of these states (toroidal and compressional responses, current distributions, and transitions probabilities $B(E1K, 0^+0 \to 1^-K),\; B(E3K, 0^+0 \to 3^-K)$, $B(M2K, 0^+0 \to 2^-K)$ with $K=$0 and 1) and analyze the possibility to discriminate and identify TS in inelastic electron scattering to back angles. The interplay of the convective ${\bf j}_{\rm c}$ and magnetization ${\bf j}_{\rm m}$ nuclear currents is thoroughly scrutinized. A two-step scheme for identification of TS in $(e,e')$ reaction is proposed. The key element of the scheme is the strong interference of the orbital and spin contributions, resulting in specific features of E1 and M2 transversal form factors., Comment: 10 pages, 9 figures. The previous version of the paper was crucially revised and enlarged in both i) description on main features and ii) proposals for (e,e') reaction. Submitted to Phys. Rev. C

We suggest a generalized method for elimination of spurious admixtures (SA) from intrinsic nuclear excitations described within the Quasiparticle-Random-Phase-Approximation (QRPA). Various kinds of SA-corrections are treated at the same theoretical ground. The known corrections are well reproduced. As relevant cases, we consider subtraction of SA related with i) violation of the translational invariance (isovector E1 and isoscalar toroidal and compression E1 modes), ii) pairing-induced non-conservation of the particle number (E2(K=0) and E0 modes), and iii) rotational invariance (E2(K=1) and M1(K=1) modes). The SA subtraction can be done at the level of QRPA states, electromagnetic responses, and even transition operators. The additional deformation-induced corrections are proposed. The accuracy of the method is demonstrated by Skyrme QRPA calculations for axially-deformed $^{154}$Sm., Comment: 13 pages, 7 figures, to be published in Phys. Rev. C

The low-lying $M1$-strength of the open-shell nucleus $^{50}$Cr has been studied with the method of nuclear resonance fluorescence up to 9.7 MeV, using bremsstrahlung at the superconducting Darmstadt linear electron accelerator S-DALINAC and Compton backscattered photons at the High Intensity $\gamma$-ray Source (HI$\gamma$S) facility between 6 and 9.7 MeV of the initial photon energy. Fifteen $1^{+}$ states have been observed between 3.6 and 9.7 MeV. Following our analysis, the lowest $1^{+}$ state at 3.6 MeV can be considered as an isovector orbital mode with some spin admixture. The obtained results generally match the estimations and trends typical for the scissors-like mode. Detailed calculations within the Skyrme Quasiparticle Random-Phase-Approximation method and the Large-Scale Shell Model justify our conclusions. The calculated distributions of the orbital current for the lowest $1^{+}$-state suggest the schematic view of Lipparini and Stringari (isovector rotation-like oscillations inside the rigid surface) rather than the scissors-like picture of Lo Iudice and Palumbo. The spin M1 resonance is shown to be mainly generated by spin-flip transitions between the orbitals of the $fp$-shell., Comment: Accepted in PRC as a regular article

The lowest quadrupole $��$-vibrational $K^��=2^+$ states in axially deformed rare-earth (Nd, Sm, Gd, Dy, Er, Yb, Hf, W) and actinide (U) nuclei are systematically investigated within the separable random-phase-approximation (SRPA) based on the Skyrme functional. The energies $E_��$ and reduced transition probabilities $B(E2)$ of $2^+_��$-states are calculated with the Skyrme forces SV-bas and SkM$^*$. The energies of two-quasiparticle configurations forming the SRPA basis are corrected by using the pairing blocking effect. This results in a systematic downshift of $E_��$ by 0.3-0.5 MeV and thus in a better agreement with the experiment, especially in Sm, Gd, Dy, Hf, and W regions. For other isotopic chains, a noticeable overestimation of $E_��$ and too weak collectivity of $2^+_��$-states still persist. It is shown that domains of nuclei with a low and high $2^+_��$ -collectivity are related with the structure of the lowest 2-quasiparticle states and conservation of the Nilsson selection rules. The description of $2^+_��$ states with SV-bas and SkM$^*$ is similar in light rare-earth nuclei but deviates in heavier nuclei. However SV-bas much better reproduces the quadrupole deformation and energy of the isoscalar giant quadrupole resonance. The accuracy of SRPA is justified by comparison with exact RPA. The calculations suggest that a further development of the self-consistent calculation schemes is needed for a systematic satisfactory description of the $2^+_��$ states., 16 pages, 10 figures, 2 tables

The isoscalar giant monopole resonance (GMR) in spherical nuclei $^{100-132}$Sn, $^{144}$Sm, and $^{208}$Pb is investigated within the Skyrme random-phase-approximation (RPA) for a variety of Skyrme forces and different pairing options. The calculated GMR strength functions are directly compared to the available experimental distributions. It is shown that, in accordance to results of other groups, description of GMR in Sn and heavier Sm/Pb nuclei needs different values of the nuclear incompressibilty, $K \approx$ 200 or 230 MeV, respectively. Thus none from the used Skyrme forces is able to describe GMR in these nuclei simultaneously. The GMR peak energy in open-shell $^{120}$Sn is found to depend on the isoscalar effective mass, which might be partly used for a solution of the above problem. Some important aspects of the problem (discrepancies of available experimental data, proper treatment of the volume and surface compression in finite nuclei, etc) are briefly discussed., Comment: 6 pages, 3 figures, submitted to Phys. Scr. (Proceed. of XXI Nuclear Physics Workshop, 23-28.09.2014, Kazimierz Dolny, Poland)

An inverse population transfer of the repulsive Bose-Einstein condensate (BEC) in a weakly bound double-well trap is explored within the 3D time-dependent Gross-Pitaevskii equation. The model avoids numerous common approximations (two-mode treatment, time-space factorization, etc) and closely follows the conditions of Heidelberg experiments, thus providing a realistic description of BEC dynamics. The transfer is driven by a time-dependent shift of a barrier separating the left and right wells. It is shown that completeness and robustness of the process considerably depend on the amplitude and time profile of the shift velocity. Soft profiles provide the most robust inversion. The repulsive interaction substantially supports the transfer making it possible i) in a wide velocity interval and ii) three orders of magnitude faster than in the ideal BEC., Comment: 6 pages, 5 figures

Two basic concepts of nuclear vorticity, hydrodynamical (HD) and Rawenthall-Wambach (RW), are critically inspected. As a test case, we consider the interplay of irrotational and vortical motion in isoscalar electric dipole E1(T=0) modes in $^{208}$Pb, namely the toroidal and compression modes. The modes are described in a self-consistent random-phase-approximation (RPA) with the Skyrme force SLy6. They are examined in terms of strength functions, transition densities, current fields, and formfactors. It is shown that the RW conception (suggesting the upper component of the nuclear current as the vorticity indicator) is not robust. The HD vorticity is not easily applicable either because the definition of a velocity field is too involved in nuclear systems. Instead, the vorticity is better characterized by the toroidal strength which closely corresponds to HD treatment and is approximately decoupled from the continuity equation., Comment: 12 pages, 9 figures

Numerical simulations of Aluminum (Al) and Tungsten (W) granular composite rings under various dynamic loading conditions caused by explosive loading were examined. Three competing mechanisms of fragmentation were observed: a continuum level mechanism generating large macrocracks described by the Grady-Kipp fragmentation mechanism, a mesoscale mechanism generating voids and microcracks near the initially unbonded Al/W interfaces due to tensile strains, and a mesoscale jetting due to the development of large velocity gradients between the W particles and adjacent Al. These mesoscale mechanisms can be used to tailor the size of the fragments by selecting an appropriate initial mesostructure for a given loading condition., Comment: 10 pages, 3 figures, submitted to APL

Представлен анализ современных научных исследований процесса профессиональной подготовки будущих педагогов в условиях заочного обучения. The paper presents an analysis of current research process training future teachers in distance learning. Нестеренко В.В., кандидат педагогических наук, доцент кафедры дошкольной педагогики, Южноукраинский национальный педагогический университет им. К.Д. Ушинского (г. Одесса). Nesterenko V.V., Candidate of Pedagogical Sciences (PhD), Associate Professor of the Department of Professor of Preschool Pedagogy South Ukrainian National Pedagogical University named after K.D. Ushinsky (the city of Odessa).

The spin-flip M1 giant resonance is explored in the framework of Random Phase Approximation on the basis of the Skyrme energy functional. A representative set of eight Skyrme parameterizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4, and SV-bas) is used. Light and heavy, spherical and deformed nuclei ($^{48}$Ca, $^{158}$Gd, $^{208}$Pb, and $^{238}$U) are considered. The calculations show that spin densities play a crucial role in forming the collective shift in the spectrum. The interplay of the collective shift and spin-orbit splitting determines the quality of the description. None of the considered Skyrme parameterizations is able to describe simultaneously the M1 strength distribution in closed-shell and open-shell nuclei. It is found that the problem lies in the relative positions of proton and neutron spin-orbit splitting. Necessity to involve the tensor and isovector spin-orbit interaction is called for., Comment: 7 pages, 6 figures

One-dimensional nonlinear phononic crystals have been assembled from periodic diatomic chains of stainless steel cylinders alternated with Polytetrafluoroethylene (PTFE) spheres. We report the presence of acoustic band gaps in the dispersion relation of the linearized systems and study the transformation of single and multiple pulses in linear, nonlinear and strongly nonlinear regimes with numerical calculations and experiments. The limiting frequencies of the band gap are within the audible frequency range (20-20,000 Hz) and can be tuned by varying the particle's material properties, mass and initial compression. Pulses rapidly transform within very short distances from the impacted end due to the influence of the band gap in the linear and in nonlinear elastic chains. The effects of an in situ band gap created by a mean dynamic compression are observed in the strongly nonlinear wave regime., Comment: 38 pages, 13 figures

The dynamic mechanical properties of reactive materials (e.g., high density mixtures of polytetraflouroethylene (PTFE), aluminum (Al) and tungsten (W) powders) can be tailored by changing the morphology of the particles and porosity. Cold isostatically pressed PTFE-Al-W powder composites with fine metallic particles and a higher porosity exhibited higher ultimate compressive strength than less porous composites having equivalent mass ratios with coarse W particles. The mesoscale force chains between the fine metallic particles are responsible for this unusual phenomenon. We observed macrocracks below the critical failure strain for the matrix and a competition between densification and fracture in some porous samples in dynamic tests., Comment: 18 pages, 5 figures

A novel strongly nonlinear laminar metamaterial supporting new types of solitary and shock waves with impact energy mitigating capabilities is presented. It consists of steel plates with intermittent polymer toroidal rings acting as strongly nonlinear springs with large allowable strain. Their force-displacement relationship is described by the addition of two power-law relationships resulting in a solitary wave speed and width depending on the amplitude. This double nonlinearity allows splitting of an initial impulse into two separate strongly nonlinear solitary wave trains. Solitary and shock waves are observed experimentally and analyzed numerically in an assembly with Teflon o-rings., Comment: 14 pages, 6 figures

We formulate the self-consistent separable random-phase-approximation (SRPA) method and specify it for Skyrme forces with pairing for the case of axially symmetric deformed nuclei. The factorization of the residual interaction allows to avoid diagonalization of high-rank RPA matrices, which dramatically reduces the computational expense. This advantage is crucial for the systems with a huge configuration space, first of all for deformed nuclei. SRPA takes self-consistently into account the contributions of both time-even and time-odd Skyrme terms as well as of the Coulomb force and pairing. The method is implemented to description of isovector E1 and isoscalar E2 giant resonances in a representative set of deformed nuclei: $^{154}$Sm, $^{238}$U, and $^{254}$No. Four different Skyrme parameterizations (SkT6, SkM*, SLy6, and SkI3) are employed to explore dependence of the strength distributions on some basic characteristics of the Skyrme functional and nuclear matter. In particular, we discuss the role of isoscalar and isovector effective masses and their relation to time-odd contributions. High sensitivity of the right flank of E1 resonance to different Skyrme forces and the related artificial structure effects are analyzed., Comment: 14 pages, 3 figures, 1 table

It is shown that the quasi-normal modes arise, in a natural way, when considering the oscillations in unbounded regions by imposing the radiation condition at spatial infinity with a complex wave vector $k$. Hence quasi-normal modes are not peculiarities of gravitation problems only (black holes and relativistic stars). It is proposed to consider the space form of the quasi-normal modes with allowance for their time dependence. As a result, the problem of their unbounded increase when $r\to \infty$ is not encountered more. The properties of quasi-normal modes of a compact dielectric sphere are discussed in detail. It is argued that the spatial form of these modes (especially so-called surface modes) should be taken into account, for example, when estimating the potential health hazards due to the use of portable telephones., Comment: 19 pages, 1 figure with two eps files, REVTEX4; presentation is improved

Properties of low-energy (infra-red) quadrupole modes (LEQM) of multipolarity $+AFw-lambda+AFw-mu =$20, 21 and 22 in deformed sodium clusters are studied within the Kohn-Sham LDA RPA approach. Possible manifestations of LEQM in stimulated Raman adiabatic passage (STIRAP) reaction are discussed. It is shown that, in free light clusters, where the low-energy spectrum is delute, LEQM can be unambiguously identified as particular electron-hole pairs. This gives a chance to reconstruct the mean field level scheme near the Fermi surface. Moreover, due to the connection with electric $+AFw-lambda+AFw-mu =$21 mode, the scissors mode can be detected. In heavy (supported) oblate clusters, LEQM are in general rather involved. Nevertheless, some interesting $+AFw-lambda+AFw-mu =$21 and 22 structures determined by specific deformation effects can be resolved. The origin of the structures is discussed in detail., Comment: 12 pages, 6 figures

Magnesium diboride (MgB2) is attractive for RF cavity application for particle accelerators because it might not show an increase of RF surface losses at high magnetic surface fields, a phenomenon that has prevented high-Tc superconducting materials such as YBCO from being used for this application. We have measured the RF surface resistance (Rs) at 21 GHz of a MgB2 sample fabricated using Hot Isostatic Press (HIP) at 200 MPa and 1000 C. The results show that polishing with 0.1-micron diamond lapping film followed by a 1500-psi DI water rinse in a clean room reduced the Rs by a factor of 6.2 at 15 K and it is the lowest compared to other published data. The Rs data near the lowest temperature (~13 K) scatter between 0.6 and 1.3 mOhm. The penetration depth and energy gap were estimated to be 263 nm and 1.9-2.7, respectively, for the polished surface., Comment: 8 pages, 9 figures, EUCAS2003

Low-energy orbital magnetic dipole excitations, known as scissors mode (SM), are studied in alkali metal clusters. Subsequent dynamic and static effects are explored. The treatment is based on a self-consistent microscopic approach using the jellium approximation for the ionic background and the Kohn-Sham mean field for the electrons. The microscopic origin of SM and its main features (structure of the mode in light and medium clusters, separation into low- and high-energy plasmons, coupling high-energy M1 scissors and E2 quadrupole plasmons, contributions of shape isomers, etc) are discussed. The scissors M1 strength acquires large values with increasing cluster size. The mode is responsible for the van Vleck paramagnetism of spin-saturated clusters. Quantum shell effects induce a fragile interplay between Langevin diamagnetism and van Vleck paramagnetism and lead to a remarkable dia-para anisotropy in magnetic susceptibility of particular light clusters. Finally, several routes for observing the SM experimentally are discussed., 21 pages, 7 figures

The Casimir energy of an infinite compact cylinder placed in a uniform unbounded medium is investigated under the continuity condition for the light velocity when crossing the interface. As a characteristic parameter in the problem the ratio $��^2=(��_1-��_2)^2/ (��_1+��_2)^-2 = (��_1-��_2)^2/(��_1+ ��_2)^2 \le 1$ is used, where $��_1$ and $��_1$ are, respectively, the permittivity and permeability of the material making up the cylinder and $��_2$ and $��_2$ are those for the surrounding medium. It is shown that the expansion of the Casimir energy in powers of this parameter begins with the term proportional to $��^4$. The explicit formulas permitting us to find numerically the Casimir energy for any fixed value of $��^2$ are obtained. Unlike a compact ball with the same properties of the materials, the Casimir forces in the problem under consideration are attractive. The implication of the calculated Casimir energy in the flux tube model of confinement is briefly discussed., REVTeX, 12 pages, 1 figure in a separate fig1.eps file, 1 table; minor corrections in English and misprints; version to be published in Phys. Rev. D15

In the $(\epsilon_1-\epsilon_2)^2$--approximation the Casimir energy of a dilute dielectric ball is derived using a simple and clear method of the mode summation. The addition theorem for the Bessel functions enables one to present in a closed form the sum over the angular momentum before the integration over the imaginary frequencies. The linear in $(\epsilon_1-\epsilon_2)$ contribution into the vacuum energy is removed by an appropriate subtraction. The role of the contact terms used in other approaches to this problem is elucidated., Comment: 14 pages, REVTeX, no figures, no tables; presentation is made better, new references are added

Multipole electric and magnetic giant resonances in metal clusters are reviewed and compared with their counterparts in atomic nuclei. The main attention is paid to E1 resonance (dipole plasmon)., Comment: LATEX, 19 pages, 4 figures

We point out that in infinite spacetime dimensions, the singularity in the interquark potential at small distances disappears if the string is anchored at one end to a heavy quark, at the other end to a light quark. This suggests that if quarks are placed at the end of strings some unphysical features such as tachyon states may be absent also in in finite dimensions., Comment: Texfile + fig.tex +fig.eps, http://www.physik.fu-berlin.de/./kleinert.html

A new approach for investigating the classical dynamics of the relativistic string model with rigidity is proposed. It is based on the embedding of the string world surface into the space of a constant curvature. It is shown that the rigid string in flat space-time is described by the Euler-Lagrange equation for the Willmore functional in a space-time of the constant curvature K=-g/(2 a), where g and a are constants in front of the Nambu-Goto term and the curvature term in the rigid string action respectively. For simplicity the Euclidean version of the rigid string in the three-dimensional space-time is considered. The Willmore functional (the action for the "Willmore string") is obtained by dropping the Nambu-Goto term in the Polyakov-Kleinert action for the rigid string. Such "reduction" of the rigid string model would be useful, for example, by applying some results about the Numbu-Goto string dynamics in the de Sitter universe to the rigid string model in the Minkowski space-time. It allows also to use numerous mathematical results about the Willmore surfaces in the context of the physical problem., Comment: 13 pp, LaTeX, JINR preprint E2-93-181

A panel of mAb (IgG1, IgG3, IgM) against Legionella pneumophila cytolysin (CL)-protease of 37 kDa was obtained. Subtyping of L. pneumophila strains of serogroup 1 by using mAb against CL (mAb-CL) was carried out. The results of comparative analysis of the specificity of mAb-CL and the panel of mAb kindly provided by Dr. J. M. Barbaree (Centers for Disease Control, Atlanta, GA) allowed us to recommend mAb-CL to be used as a diagnostic tool to reveal the pathogenicity of L. pneumophila strains of serogroup 1. Hybridomas were also raised in a syngenic system which produced anti-idiotypic mAb (mAb2) against anti-CL mAb B6/1. The Ab2 belonged to Ab2 gamma type: 1) Ab2 reacted with B6/1 Id only, 2) Ab2 inhibited the interaction of B6/1 Ab1 with CL, and 3) CL inhibited the reaction of Ab2 with Ab1. The use of Ab2 allowed us to show that B6/1 Id is expressed in 4 to 32% of serum antibodies during the primary and secondary immune responses of BALB/c mice to CL. Ab2 induced the production of anti-anti-idiotypic antibodies (Ab3) in BALB/c mice, and some of them reacted with CL. Thus, we have demonstrated the possibility of inducing an antibody response to CL (one of the main L. pneumophila pathogenic factors) in intact syngenic mice with anti-idiotypic antibodies.

Synapse-associated protein 97 (SAP97) is a scaffolding protein crucial for the functional expression of several cardiac ion channels and therefore proper cardiac excitability. Alterations in the functional expression of SAP97 can modify the ionic currents underlying the cardiac action potential and consequently confer susceptibility for arrhythmogenesis. In this study, we generated a murine model for inducible, cardiac-targeted Sap97 ablation to investigate arrhythmia susceptibility and the underlying molecular mechanisms. Furthermore, we sought to identify human SAP97 (DLG1) variants that were associated with inherited arrhythmogenic disease. The murine model of cardiac-specific Sap97 ablation demonstrated several ECG abnormalities, pronounced action potential prolongation subject to high incidence of arrhythmogenic afterdepolarizations and notable alterations in the activity of the main cardiac ion channels. However, no DLG1 mutations were found in 40 unrelated cases of genetically elusive long QT syndrome (LQTS). Instead, we provide the first evidence implicating a gain of function in human DLG1 mutation resulting in an increase in Kv4.3 current (I(to)) as a novel, potentially pathogenic substrate for Brugada syndrome (BrS). In conclusion, DLG1 joins a growing list of genes encoding ion channel interacting proteins (ChIPs) identified as potential channelopathy-susceptibility genes because of their ability to regulate the trafficking, targeting, and modulation of ion channels that are critical for the generation and propagation of the cardiac electrical impulse. Dysfunction in these critical components of cardiac excitability can potentially result in fatal cardiac disease. NEW & NOTEWORTHY The gene encoding SAP97 (DLG1) joins a growing list of genes encoding ion channel-interacting proteins (ChIPs) identified as potential channelopathy-susceptibility genes because of their ability to regulate the trafficking, targeting, and modulation of ion channels that are critical for the generation and propagation of the cardiac electrical impulse. In this study we provide the first data supporting DLG1-encoded SAP97’s candidacy as a minor Brugada syndrome susceptibility gene.