Abstract:
Piericidin A1, 3’-rhamnopiericidin A1, and a novel compound piericidin E, a new quorum-sensing (QS) inhibitor
against Chromobacterium violaceum CV026, were isolated from the culture broth of Streptomyces sp. QS is well
known as a microbial signaling system and controls certain types of gene expression resulting in bioluminescence,
biofilm formation, swarming motility, antibiotic biosynthesis, and virulence factor production. C. violaceum CV026 is
commonly used to determine qualitative and quantitative QS activity. The structures of piericidin derivatives were characterized,
and their QS activities were determined.

Abstract:
We study spin-state transition and phase separation involving this transition based on the milti-orbital Hubbard model. Multiple spin states are realized by changing the energy separation between the two orbitals and the on-site Hund coupling. By utilizing the variational Monte-Carlo simulation, we analyze the electronic and magnetic structures in hole doped and undoped states. Electronic phase separation occurs between the low-spin band insulating state and the high-spin ferromagnetic metallic one. Difference of the band widths in the two orbitals is of prime importance for the spin-state transition and the phase separation.

Abstract:
We study the phase diagram of R_{1-x}A_xMnO_3 (R=La, Pr, Nd, Sm ; A=Ca, Sr, Ba) by taking into account the degeneracy of $e_g$ orbitals and the anisotropy of the transfer integral. The electron-electron interaction is treated in the mean field approximation with the optimization of the spin and orbital structures. The global phase diagram is understood in terms of the two interactions, i.e., the super exchange interaction for small $x$ and the double exchange interaction for larger $x$ modified by the orbital degeneracy. The dimensionality of the electronic energy band resulting from the orbital structure is essential to determine the phase diagram. The effects of the Jahn-Teller distortion are also studied.

Abstract:
We study theoretically the phase diagram of perovskite manganites taking into account the double degeneracy of the $e_g$ orbitals in a $Mn^{3+}$ ion. A rich phase diagram is obtained in the mean field theory at zero temperature as functions of $x$ (hole concentration) and $J_S$ (antiferromagnetic interaction between $t_{2g}$ spins). The global features of the phase diagram is understood in terms of the superexchange and double exchange interactions, which are strongly depends on types of the occupied $e_g$ orbitals. The strong electron correlation induces the orbital polarization, which controls the dimension of the conduction band. A sequential change of the spin and orbital structures with doping holes is consistent with the recent experiments. In particular, metallic A-type (layered) antiferromagnetic state is found for $x\sim0.5$ with the uniform $d_{x^2-y^2}$ orbital ordering. Effects of the Jahn-Teller distortion are also studied. A short version of this paper has been already published (to appear in PRB-rapid June), but this paper contains additional and more detailed results.

Abstract:
This paper describes our ongoing work on security verification against inference attacks on data trees. We focus on infinite secrecy against inference attacks, which means that attackers cannot narrow down the candidates for the value of the sensitive information to finite by available information to the attackers. Our purpose is to propose a model under which infinite secrecy is decidable. To be specific, we first propose tree transducers which are expressive enough to represent practical queries. Then, in order to represent attackers' knowledge, we propose data tree types such that type inference and inverse type inference on those tree transducers are possible with respect to data tree types, and infiniteness of data tree types is decidable.

Abstract:
Tracking many cells in time-lapse 3D image sequences is an important challenging task of bioimage informatics. Motivated by a study of brain-wide 4D imaging of neural activity in C. elegans, we present a new method of multi-cell tracking. Data types to which the method is applicable are characterized as follows: (i) cells are imaged as globular-like objects, (ii) it is difficult to distinguish cells based only on shape and size, (iii) the number of imaged cells ranges in several hundreds, (iv) moves of nearly-located cells are strongly correlated and (v) cells do not divide. We developed a tracking software suite which we call SPF-CellTracker. Incorporating dependency on cells' moves into prediction model is the key to reduce the tracking errors: cell-switching and coalescence of tracked positions. We model target cells' correlated moves as a Markov random field and we also derive a fast computation algorithm, which we call spatial particle filter. With the live-imaging data of nuclei of C. elegans neurons in which approximately 120 nuclei of neurons are imaged, we demonstrate an advantage of the proposed method over the standard particle filter and a method developed by Tokunaga et al. (2014).

Abstract:
The purpose of this study was to examine the relationship among self-determined friendship motivation (motivation for friendship formation), aggression, and self-esteem in a sample of 262 Japanese university students. The hypothetical model posited that self-determined friendship motivation predicted lower levels of aggression, which, in turn, predicted lower levels of self-esteem. The results showed that self-determined friendship motivation predicted lower levels of anger, hostility, and physical aggression and that hostility and anger predicted lower levels of self-esteem. Verbal aggression was found to be positively associated with self-determined friendship motivation and self-esteem. The different relationships between self-determined friendship motivation and each facet of aggression are discussed.

Abstract:
In this paper, we shed light on the Pareto
distribution of wealth on the basis of an overlapping generation model. We
deduce in the model that the basic reason for a particular shape of Pareto
distribution is attributed to the distribution of utility function among consumers.
More specifically, we show that a formula relating the distribution of utility
function to the distribution of wealth is analytically obtainable on the basis
of the Cobb-Douglas utility function. By simulation, we recognize that the
formula actually gives us a well approximation of a Pareto distribution.