Nova Cygni 2001/2 = V2275 Cyg

We present an analysis of low- and medium resolution spectra of the very fast nova, Nova Cygni 2001/2 (V2275 Cyg) obtained at nine epochs in August, September and October, 2001. The expansion velocity from hydrogen Balmer lines is found to be 2100 km/s, although early H-alpha profile showed a weak feature at -3500 km/s, too. The overall appearance of the optical spectrum is dominated by broad lines of H, He and N, therefore, the star belongs to the ``He/N'' subclass of novae defined by Williams (1992). Interstellar lines and bands, as well as BV photometry taken from the literature yielded to a fairly high reddening of E(B-V)=1.0+/-0.1 mag. The visual light curve was used to deduce M_V by the maximum magnitude versus rate of decline relationship. The resulting parameters are: t_0=2452141.4(+0.1)(-0.5), t_2=2.9+/-0.5 days, t_3=7+/-1 days, M_V=-9.7+/-0.7 mag. Adopting these parameters, the star lies between 3 kpc and 8 kpc from the Sun.Comment: 5 pages, 5 figures, accepted for publication in A&

Rapid convergence of time-averaged frequency in phase synchronized systems

Numerical and experimental evidence is presented to show that many phase synchronized systems of non-identical chaotic oscillators, where the chaotic state is reached through a period-doubling cascade, show rapid convergence of the time-averaged frequency. The speed of convergence toward the natural frequency scales as the inverse of the measurement period. The results also suggest an explanation for why such chaotic oscillators can be phase synchronized.Comment: 6 pages, 9 figure

Medium-resolution echelle spectroscopy of pulsating variables and exoplanet host stars with sub-meter telescopes

Here we present two of our interesting results obtained over the last 18 months from spectroscopic monitoring of binary pulsating stars and exoplanet host stars. Our investigations are very promising by demonstrating that modern fiber-fed spectrographs open a whole new chapter in the life of small national and university observatories.Comment: 3 pages, 3 figures. To be published in the proceedings of the workshop on "Observing techniques, instrumentation and science for metre-class telescopes", Sep. 2013, Tatranska Lomnica, Slovaki

Teleportation: from probability distributions to quantum states

The role of the off-diagonal density matrix elements of the entangled pair is investigated in quantum teleportation of a qbit. The dependence between them and the off-diagonal elements of the teleported density matrix is shown to be linear. In this way the ideal quantum teleportation is related to an entirely classical communication protocol: the one-time pad cypher. The latter can be regarded as the classical counterpart of Bennett's quantum teleportation scheme. The quantum-to-classical transition is demonstrated on the statistics of a gedankenexperiment.Comment: 11 pages, 1 figure, accepted for publication in J. Phys. A (Math. Gen.

Ageing as a price of cooperation and complexity: Self-organization of complex systems causes the ageing of constituent networks

The analysis of network topology and dynamics is increasingly used for the description of the structure, function and evolution of complex systems. Here we summarize key aspects of the evolvability and robustness of the hierarchical network-set of macromolecules, cells, organisms, and ecosystems. Listing the costs and benefits of cooperation as a necessary behaviour to build this network hierarchy, we outline the major hypothesis of the paper: the emergence of hierarchical complexity needs cooperation leading to the ageing of the constituent networks. Local cooperation in a stable environment may lead to over-optimization developing an ‘always-old’ network, which ages slowly, and dies in an apoptosis-like process. Global cooperation by exploring a rapidly changing environment may cause an occasional over-perturbation exhausting system-resources, causing rapid degradation, ageing and death of an otherwise ‘forever-young’ network in a necrosis-like process. Giving a number of examples we explain how local and global cooperation can both evoke and help successful ageing. Finally, we show how various forms of cooperation and consequent ageing emerge as key elements in all major steps of evolution from the formation of protocells to the establishment of the globalized, modern human society. Thus, ageing emerges as a price of complexity, which is going hand-in-hand with cooperation enhancing each other in a successful community

The first high-amplitude delta Scuti star in an eclipsing binary system

We report the discovery of the first high-amplitude delta Scuti star in an eclipsing binary, which we have designated UNSW-V-500. The system is an Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag. A best-fitting solution to the binary light curve and two radial velocity curves is derived using the Wilson-Devinney code. We identify a late A spectral type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees, and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals from this solution is performed using PERIOD04 to investigate the delta Scuti pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d, and it appears this is the first overtone radial mode frequency. This system provides the first opportunity to measure the dynamical mass for a star of this variable type; previously, masses have been derived from stellar evolution and pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size change, small typographical changes to abstrac

TWO-PROTON RADIOACTIVITY: THE INTERESTING CASE OF 67Kr AND FURTHER STUDIES

We report on the observation of 67Kr that has been produced in an experiment performed at the RIKEN/BigRIPS facility. The two-proton decay of 67Kr has been evidenced and this nucleus is thus the fourth observed long lived ground-state two-proton emitter, after 45Fe, 48Ni and 54Zn. In addition, the decay of several isotopes in the mass region has been investigated. While for previous cases of two-proton radioactivity, the theoretical models could reproduce the measured data, this is not the case anymore for 67Kr. Two interpretations have been proposed to explain this discrepancy: a transition between real two-proton and sequential decay or the influence of deformation. These hypotheses will be tested in future experiments by measuring the angular and energy correlations of the emitted proton