Emerging cell array based on reaction-diffusion

This article demonstrates the self-replication and self-organization phenomena based on a reaction-diffusion mechanism by computer simulation. The simulation model consists of a one-dimensional cell array. Each cell contains two kinds of chemical substances, activator u and inhibitor v, that can generate a reaction-diffusion wave, which is a spatial concentration pattern. The cells are supposed to be divided or deleted depending on the concentrations of chemical substances. We tried several kinds of diffusion coefficient in the model, and in some simulations, a self-replication process and a generating cell array with a metabolic process were observed. By applying the division rule and the apoptosis rule, cell arrays duplicate in two oscillating states, i.e., self-replication processes were observed. By applying a division rule and an annihilation rule, a cell array that has a stable length is generated by changing the cell components, i.e., generating a cell array by a metabolic process was observed. Surprisingly, these two phenomena are realized independently of the initial number of cell

Charge ordering in \theta-(BEDT-TTF)2RbZn(SCN)4: Cooperative effects of electron correlations and lattice distortions

Combined effects of electron correlations and lattice distortions are investigated on the charge ordering in \theta-(BEDT-TTF)2RbZn(SCN)4 theoretically in a two-dimensional 3/4-filled extended Hubbard model with electron-lattice couplings. It is known that this material undergoes a phase transition from a high-symmetry metallic state to a low-symmetry insulating state with a horizontal-stripe charge order (CO) by lowering temperature. By means of the exact-diagonalization method, we show that electron-phonon interactions are crucial to stabilize the horizontal-stripe CO and to realize the low-symmetry crystal structure.Comment: 7 peges, 7 figures, accepted for publication in Phys. Rev.

Mott insulating state in a quarter-filled two-orbital Hubbard chain with different bandwidths

We investigate the ground-state properties of the one-dimensional two-band Hubbard model with different bandwidths. The density-matrix renormalization group method is applied to calculate the averaged electron occupancies $n$ as a function of the chemical potential $\mu$. Both at quarter and half fillings, "charge plateaux" appear in the $n$-$\mu$ plot, where $d\mu/dn$ diverges and the Mott insulating states are realized. To see how the orbital polarization in the one-quarter charge plateau develops, we apply the second-order perturbation theory from the strong-coupling limit at quarter filling. The resultant Kugel-Khomskii spin-orbital model includes a $magnetic$ field coupled to orbital pseudo-spins. This field originates from the discrepancy between the two bandwidths and leads to a finite orbital pseudo-spin magnetization.Comment: 4 pages, 2 figures, Proceedings of LT2

Occupational health in the corporate social responsibility (CSR) among Japanese companies

The aim of the present study was to clarify an association between the prevalence of Raynaud’s phenomenon in workers using an impact wrench and the effect of various countermeasures to prevent adverse health effects of vibration over a period of 27 yr. The subjects were 704 workers who were regularly using an impact wrench and taking special medical examinations for vibration syndrome in a factory from 1981 to 2008. Practical countermeasures, such as improvement of an apparatus and control of working conditions, were taken twenty times. There were 39 subjects with Raynaud’s phenomenon at least one time during the observation period. The prevalence of Raynaud’s phenomenon decreased after introduction of the improved impact wrench. Thereafter, the prevalence of Raynaud’s phenomenon remained to be about 2–5 % although various countermeasures were taken to keep the working environments warm, reduce the working time, and improve other working conditions. These fi ndings showed that it is necessary to decrease the vibration level of an impact wrench to decrease the prevalence of Raynaud’s phenomenon

Prevalence of Raynaud’s Phenomenon and Countermeasures for Workers Using an Impact Wrench

The aim of the present study was to clarify an association between the prevalence of Raynaud’s phenomenon in workers using an impact wrench and the effect of various countermeasures to prevent adverse health effects of vibration over a period of 27 yr. The subjects were 704 workers who were regularly using an impact wrench and taking special medical examinations for vibration syndrome in a factory from 1981 to 2008. Practical countermeasures, such as improvement of an apparatus and control of working conditions, were taken twenty times. There were 39 subjects with Raynaud’s phenomenon at least one time during the observation period. The prevalence of Raynaud’s phenomenon decreased after introduction of the improved impact wrench. Thereafter, the prevalence of Raynaud’s phenomenon remained to be about 2–5 % although various countermeasures were taken to keep the working environments warm, reduce the working time, and improve other working conditions. These fi ndings showed that it is necessary to decrease the vibration level of an impact wrench to decrease the prevalence of Raynaud’s phenomenon

Transcriptionally linked simultaneous overexpression of P450 genes for broad-spectrum herbicide resistance

雑草が獲得した最強の除草剤抵抗性メカニズムの解明 --解毒酵素の一斉活性化--. 京都大学プレスリリース. 2023-06-14.Broad-spectrum herbicide resistance (BSHR), often linked to weeds with metabolism-based herbicide resistance, poses a threat to food production. Past studies have revealed that overexpression of catalytically promiscuous enzymes explains BSHR in some weeds; however, the mechanism of BSHR expression remains poorly understood. Here, we investigated the molecular basis of high-level resistance to diclofop-methyl in BSHR late watergrass (Echinochloa phyllopogon) found in the United States, which cannot be solely explained by the overexpression of promiscuous cytochrome P450 monooxygenases CYP81A12/21. The BSHR late watergrass line rapidly produced 2 distinct hydroxylated diclofop acids, only 1 of which was the major metabolite produced by CYP81A12/21. RNA-seq and subsequent reverse transcription quantitative PCR (RT-qPCR)-based segregation screening identified the transcriptionally linked overexpression of a gene, CYP709C69, with CYP81A12/21 in the BSHR line. The gene conferred diclofop-methyl resistance in plants and produced another hydroxylated diclofop acid in yeast (Saccharomyces cerevisiae). Unlike CYP81A12/21, CYP709C69 showed no other herbicide-metabolizing function except for a presumed clomazone-activating function. The overexpression of the 3 herbicide-metabolizing genes was also identified in another BSHR late watergrass in Japan, suggesting a convergence of BSHR evolution at the molecular level. Synteny analysis of the P450 genes implied that they are located at mutually independent loci, which supports the idea that a single trans-element regulates the 3 genes. We propose that transcriptionally linked simultaneous overexpression of herbicide-metabolizing genes enhances and broadens the metabolic resistance in weeds. The convergence of the complex mechanism in BSHR late watergrass from 2 countries suggests that BSHR evolved through co-opting a conserved gene regulatory system in late watergrass

スケトウダラ着底トロール調査におけるワープ長の違いが網形状と漁獲に与える影響

We examined variation in trawl dimension, bottom contact, and catch with differing warp lengths during walleye pollock surveys conducted by the Fisheries Research Agency. The ratio of warp length to fishing depth (scope ratio) was set at 2.5, 3.0 and 3.5 at depths of 110 m. At a 2.5 scope ratio, the net mouth shape and footgear contact fluctuated, as the trawl door did not contact the bottom. Footgear contact was complete when the scope ratio was 3.0 or more. Walleye pollock, sculpins, and flatfishes were the main catch in all tows, and the catch increased with scope ratio. There was no difference in the length frequency of n= 300 walleye pollock captured at 2.5 and 3.0 scope ratio. However, the length frequency at 3.5 was significantly different from that of other scope ratios. These results suggest the following: at a scope ratio of 3.0 or more, the trawl door will not leave the bottom at any depths. To compliment echo surveys for walleye pollock, a 3.0 scope ratio would be optimal, since the catch data for a 3.5 scope ratio was dissimilar from that of scope ratios

Risk prediction of landslide and debris flow using slope gradation map obtained from airborne laser scanning

The slope gradation map which is obtained from airborne laser scanning is very important tool to detect hazardous sites of landslide, debris flow and others. The features of the images (what the images are represented) in the map were confirmed by field survey. The study area, Tamagashi is situated in the Kibi Plateau area, Okayama City, Japan. The map helps to distinguish between artificial microrelief and natural microtopography very well. Small scarps (even 0.5m high), rocky cliffs and large blocks (larger than 2m) are identified in the map. The detail images of the microrelief suggest threatening sites. The merit of the map leads us to find the site in the field easily. We will not miss the threatening sites by using the map