Statistical properties of chaotic microcavities in small and large opening cases

We study the crossover behavior of statistical properties of eigenvalues in a chaotic microcavity with different refractive indices. The level spacing distributions change from Wigner to Poisson distributions as the refractive index of a microcavity decreases. We propose a non-hermitian matrix model with random elements describing the spectral properties of the chaotic microcavity, which exhibits the crossover behaviors as the opening strength increases.Comment: 22 pages, 6 figure

Quasiattractors in coupled maps and coupled dielectric cavities

We study the origin of attracting phenomena in the ray dynamics of coupled optical microcavities. To this end we investigate a combined map that is composed of standard and linear map, and a selection rule that defines when which map has to be used. We find that this system shows attracting dynamics, leading exactly to a quasiattractor, due to collapse of phase space. For coupled dielectric disks, we derive the corresponding mapping based on a ray model with deterministic selection rule and study the quasiattractor obtained from it. We also discuss a generalized Poincar\'e surface of section at dielectric interfaces.Comment: 7 pages, 7 figure

Batalin-Tyutin Quantization of the Chiral Schwinger Model

We quantize the chiral Schwinger Model by using the Batalin-Tyutin formalism. We show that one can systematically construct the first class constraints and the desired involutive Hamiltonian, which naturally generates all secondary constraints. For $a>1$, this Hamiltonian gives the gauge invariant Lagrangian including the well-known Wess-Zumino terms, while for $a=1$ the corresponding Lagrangian has the additional new type of the Wess-Zumino terms, which are irrelevant to the gauge symmetry.Comment: 15 pages, latex, no figures, to be published in Z. Phys. C (1995

Amplitude death in a ring of nonidentical nonlinear oscillators with unidirectional coupling

We study the collective behaviors in a ring of coupled nonidentical nonlinear oscillators with unidirectional coupling, of which natural frequencies are distributed in a random way. We find the amplitude death phenomena in the case of unidirectional couplings and discuss the differences between the cases of bidirectional and unidirectional couplings. There are three main differences; there exists neither partial amplitude death nor local clustering behavior but oblique line structure which represents directional signal flow on the spatio-temporal patterns in the unidirectional coupling case. The unidirectional coupling has the advantage of easily obtaining global amplitude death in a ring of coupled oscillators with randomly distributed natural frequency. Finally, we explain the results using the eigenvalue analysis of Jacobian matrix at the origin and also discuss the transition of dynamical behavior coming from connection structure as coupling strength increases.Comment: 14 pages, 11 figure

Cases of ethical violation in research publications: through editorial decision making process

Purpose – To improve and strengthen existing publication and research ethics, KODISA has identified and presented various cases which have violated publication and research ethics and principles in recent years. The editorial office of KODISA has been providing and continues to provide advice and feedback on publication ethics to researchers during peer review and editorial decision making process. Providing advice and feedback on publication ethics will ensure researchers to have an opportunity to correct their mistakes or make appropriate decisions and avoid any violations in research ethics. The purpose of this paper is to identify different cases of ethical violation in research and inform and educate researchers to avoid any violations in publication and research ethics. Furthermore, this article will demonstrate how KODISA journals identify and penalize ethical violations and strengthens its publication ethics and practices. Research design, data and methodology – This paper examines different types of ethical violation in publication and research ethics. The paper identifies and analyzes all ethical violations in research and combines them into five general categories. Those five general types of ethical violations are thoroughly examined and discussed. Results – Ethical violations of research occur in various forms at regular intervals; in other words, unethical researchers tend to commit different types of ethical violations repeatedly at same time. The five categories of ethical violation in research are as follows: (1) Arbitrary changes or additions in author(s) happen frequently in thesis/dissertation related publications. (2) Self plagiarism, submitting same work or mixture of previous works with or without using proper citations, also occurs frequently, but the most common type of plagiarism is changing the statistical results and using them to present as the results of the empirical analysis; (3) Translation plagiarism, another ethical violation in publication, is difficult to detect but occurs frequently; (4) Fabrication of data or statistical analysis also occurs frequently. KODISA requires authors to submit the results of the empirical analysis of the paper (the output of the statistical program) to prevent this type of ethical violation; (5) Mashup or aggregator plagiarism, submitting a mix of several different works with or without proper citations without alterations, is very difficult to detect, and KODISA journals consider this type of plagiarism as the worst ethical violation. Conclusions – There are some individual cases of ethical violation in research and publication that could not be included in the five categories presented throughout the paper. KODISA and its editorial office should continue to develop, revise, and strengthen their publication ethics, to learn and share different ways to detect any ethical violations in research and publication, to train and educate its editorial members and researchers, and to analyze and share different cases of ethical violations with the scholarly community

Overexpression and characterization of a thermophilic and hemolytic phospholipase of Vibrio vulnificus cloned in Escherichia coli (phospholipase of V. vulnificus)

A phospholipase (PLase) gene of Vibrio vulnificus was cloned in Escherichia coli and the properties of the gene product were investigated. The PLase structural gene was composed of 1,251 bp, encoding 417 amino acids for a protein with a predicted molecular mass of 47,187 Da including a putative signal sequence. The predicted protein sequence was 87 and 82% identical to those of hemolysins from Vibrio spp. and that of lecithinase from V. cholerae, respectively. A lipid binding motif, GDSL, conserved among various PLases and lipases was also observed. Over-expression of PLase caused inclusion body formation in E. coli, but not that of the PLase subclone without the signal sequence (45 kDa). Purified PLase exhibited hemolytic activity on red blood cells and hydrolyzed phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and soya-lecithin mainly to fatty acid and 1,2-diacylglycerol, indicating that it was a PLase with unique catalytic activity. PLase from V. vulnificus had temperature and pH optimum at 45°C and 7.0 in 50 mM Tris-HCl buffer, respectively, but was quite active at temperatures up to 55°C and in a broad range of pH 5 to 10. The activity of the enzyme was enhanced by divalent cations such as Ca2+, Co2+, Mg2+, and Mn2+, but not by ethylenediaminetetraacetic acid (EDTA).Key words: Phospholipase, Vibrio vulnificus, hemolytic, VplA