Multichannel dynamical symmetry and cluster-coexistence

A composite symmetry of the nuclear structure, called multichannel dynamical symmetry is established. It can describe different cluster configurations (defined by different reaction channels) in a unified framework, thus it has a considerable predictive power. The two-channel case is presented in detail, and its conceptual similarity to the dynamical supersymmetry is discussed.Comment: published in Phys. Rev. C 87,067301 (2013

Relation between the phenomenological interactions of the algebraic cluster model and the effective two--nucleon forces

We determine the phenomenological cluster--cluster interactions of the algebraic model corresponding to the most often used effective two--nucleon forces for the $^{16}$O + $\alpha$ system.Comment: Latex with Revtex, 1 figure available on reques

Constraining the parameters of the putative supermassive binary black hole in PG 1302-102 from its radio structure

We investigate the pc-scale kinematics and kpc-scale radio morphology of the quasar PG 1302-102, which may harbour a sub-pc separation supermassive binary black hole system at its centre as inferred from optical variability. High-resolution radio interferometric measurements obtained with the Very Long Baseline Array (VLBA) in the Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) programme at 15 GHz at 20 epochs spanning 17 years were analysed to investigate the pc-scale radio structure. Archival observations with the Very Large Array (VLA) at 1.4 GHz and 5 GHz were obtained to study the kpc-scale morphology. We find that the pc-scale jet is inclined within ~2.2 deg to the line of sight and has a half-opening angle of about 0.2 deg. The parameters derived from the pc-scale radio jet are qualitatively consistent with those obtained from the analysis of the optical light curve of PG 1302-102. We obtain at least 0.08 for the mass ratio of the two black holes in the system. We find some indication for a helical jet structure on kpc-scale, but the directions of the inner and the extended radio jets are significantly different, obstructing a straightforward connection of the pc- and kpc-scale jets within the binary scenario.Comment: 9 pages, 4 figures, 1 table, accepted to MNRA

VLBI observation of the newly discovered z=5.18 quasar SDSS J0131-0321

Few high-redshift, radio-loud quasars are known to date. The extremely luminous, radio-bright quasar, SDSS J013127.34-032100.1 was recently discovered at a redshift of $z=5.18$. We observed the source with high resolution very long baseline interferometry (VLBI) at 1.7 GHz with the European VLBI Network (EVN) and found a single compact radio component. We estimated a lower limit to the brightness temperature of the detected radio component, T_B~10^{11} K. Additionaly, when compared to archival radio data, the source showed significant flux density variation. These two findings are indicative of the blazar nature of the source.Comment: 5 pages, 2 figures. Accepted for publication in MNRAS Letter

A DigitalCAT: A Fusion of Creativity Assessment Theory and HCI

As a ‘gold standard’ creativity assessment method, it is important to reflect on the digital future of Amabile’s Consensual Assessment Technique (CAT). Over the past three decades, the CAT has given creativity researchers a formal tool on which to build a true science out of the subjective phenomenon of creativity in a vast range of domains. Research practice, however, has relied on primitive paper-based tools or only rudimentary digital technology. As a result, it is high time a more sophisticated, standardized research tool is developed to greatly facilitate future creativity research and assessment - a DigitalCAT - building on expertise from the design research, psychology and human-computer interaction (HCI) disciplines

Proxy-SU(3) symmetry in the shell model basis

The proxy-SU(3) symmetry has been proposed for spin-orbit like nuclear shells using the asymptotic deformed oscillator basis for the single particle orbitals, in which the restoration of the symmetry of the harmonic oscillator shells is achieved by a change of the number of quanta in the z-direction by one unit for the intruder parity orbitals. The same definition suffices within the cartesian basis of the Elliott SU(3) model. Through a mapping of the cartesian Elliott basis onto the spherical shell model basis, we translate the proxy-SU(3) approximation into spherical coordinates, proving, that in the spherical shell model basis the proxy-SU(3) approximation corresponds to the replacement of the intruder parity orbitals by their de Shalit--Goldhaber partners. Furthermore it is shown, that the proxy-SU(3) approximation in the cartesian Elliott basis is equivalent to a unitary transformation in the z-coordinate, leaving the x-y plane intact, a result which in the asymptotic deformed oscillator coordinates implies, that the z-projections of angular momenta and spin remain unchanged. The present work offers a microscopic justification of the proxy-SU(3) approximation and in addition paves the way, for taking advantage of the proxy-SU(3) symmetry in shell model calculations.Comment: 15 pages, 7 tables, 1 figur

Vegetation history, recent dynamics and future prospects of a Hungarian sandy forest-steppe reserve: forest-grassland relations, tree species composition and size-class distribution

Pannonian forest-steppes host a high number of endemic species and contribute to landscape-scale heterogeneity. Alterations in the proportion of forests and grasslands due to changes in land-use practice and climatic parameters can have serious nature conservation consequences. Hypotheses about forest-steppe dynamics have rarely been verified by detailed analyses, especially for the sandy forest-steppes. We integrated historical analysis, aerial photo interpretation and field investigation to determine how vegetation of a sandy forest-steppe has changed, how current dynamical processes operate and how native and exotic tree species regenerate under present conditions. The vegetation of the study area before the onset of major anthropogenic environmental transformations in the Carpathian Basin may have been a mosaic of forested and unforested patches. However, there is strong evidence that after heavy deforestation, the region was almost completely treeless between the 15th and the 19th centuries. Forest cover was able to recover by the 1800s but the lack of forested areas in the region for centuries explains why forest patches are still poor in species. Grasslands, which existed continuously, are more diverse, supporting several rare and endemic species. From 1953 till 2013, 72.45% of the area proved to be stable, but 27.55% showed clear dynamical character, changing either from forest to grassland, or vice versa. Thus, cyclic dynamics can occur in sandy forest-steppes. We found that forest patches of different size, differently exposed edges and grasslands provide different habitats for the tree species. Exotic species were present in large numbers, probably due to the small size of the reserve and the lack of a buffer zone

Into the central 10 pc of the most distant known radio quasar. VLBI imaging observations of J1429+5447 at z=6.21

Context: There are about 60 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio above 1 mJy flux density at 1.4 GHz frequency. Among them, J1429+5447 (z=6.21) is the highest-redshift radio quasar known at present. These rare, distant, and powerful objects provide important insight into the activity of the supermassive black holes in the Universe at early cosmological epochs, and on the physical conditions in their environment. Aims: We studied the compact radio structure of J1429+5447 on the milli-arcsecond (mas) angular scale, in order to compare the structural and spectral properties with those of other two z~6 radio-loud quasars, J0836+0054 (z=5.77) and J1427+3312 (z=6.12). Methods: We performed Very Long Baseline Interferometry (VLBI) imaging observations of J1429+5447 with the European VLBI Network (EVN) at 1.6 GHz on 2010 June 8, and at 5 GHz on 2010 May 27. Results: Based on its observed radio properties, the compact but somewhat resolved structure on linear scales of <100 pc, and the steep spectrum, the quasar J1429+5447 is remarkably similar to J0836+0054 and J1427+3312. To answer the question whether the compact steep-spectrum radio emission is a "universal" feature of the most distant radio quasars, it is essential to study more, yet to be discovered radio-loud active galactic nuclei at z>6.Comment: 4 pages, 2 figures, accepted for publication as a Letter to the editor in Astronomy & Astrophyic

Radio interferometric observations of two core-dominated triple radio sources at z>3

Aims. We selected two radio quasars (J1036+1326 and J1353+5725) based on their 1.4-GHz radio structure, which is dominated by a bright central core and a pair of weaker and nearly symmetric lobes at ~10" angular separation. They are optically identified in the Sloan Digital Sky Survey (SDSS) at spectroscopic redshifts z>3. We investigate the possibility that their core-dominated triple morphology can be a sign of restarted radio activity in these quasars, involving a significant repositioning of the radio jet axis. Methods. We present the results of high-resolution radio imaging observations of J1036+1326 and J1353+5725, performed with the European Very Long Baseline Interferometry (VLBI) Network (EVN) at 1.6 GHz. These data are supplemented by archive observations from the Very Large Array (VLA).We study the large- and small-scale radio structures and the brightness temperatures, then estimate relativistic beaming parameters. Results. We show that the central emission region of these two high-redshift, core-dominated triple sources is compact but resolved at ~10 milli-arcsecond resolution. We find that it is not necessary to invoke large misalignment between the VLBI jet and the large-scale radio structure to explain the observed properties of the sources.Comment: 5 pages, 4 figures, accepted for publication in A&