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

Toward reliable algorithmic self-assembly of DNA tiles: A fixed-width cellular automaton pattern

Bottom-up fabrication of nanoscale structures relies on chemical processes to direct self-assembly. The complexity, precision, and yield achievable by a one-pot reaction are limited by our ability to encode assembly instructions into the molecules themselves. Nucleic acids provide a platform for investigating these issues, as molecular structure and intramolecular interactions can encode growth rules. Here, we use DNA tiles and DNA origami to grow crystals containing a cellular automaton pattern. In a one-pot annealing reaction, 250 DNA strands first assemble into a set of 10 free tile types and a seed structure, then the free tiles grow algorithmically from the seed according to the automaton rules. In our experiments, crystals grew to ~300 nm long, containing ~300 tiles with an initial assembly error rate of ~1.4% per tile. This work provides evidence that programmable molecular self-assembly may be sufficient to create a wide range of complex objects in one-pot reactions

Design Automation of Polyomino Set That Self-Assembles into a Desired Shape

The problem of finding the smallest DNA tile set that self-assembles into a desired pattern or shape is a research focus that has been investigated by many researchers. In this paper, we take a polyomino, which is a non-square element composed of several connected square units, as an element of assembly and consider the design problem of the minimal set of polyominoes that self-assembles into a desired shape. We developed a self-assembly simulator of polyominoes based on the agent-based Monte Carlo method, in which the potential energy among the polyominoes is evaluated and the simulation state is updated toward the direction to decrease the total potential. Aggregated polyominoes are represented as an agent, which can move, merge, and split during the simulation. In order to search the minimal set of polyominoes, two-step evaluation strategy is adopted, because of enormous search space including many parameters such as the shape, the size, and the glue types attached to the polyominoes. The feasibility of the proposed method is shown through three examples with different size and complexity

Design of vehicle instrumental panel for older adults : Effects of viewing distance, display form, and switch arrangement on secondary task performance

The effects of age, viewing distance, arrangement of switches and display form on performance to the design of display and control systems friendly to older adults were discussed. A dual-task experiment was conducted in which the primary task was first-order tracking. The secondary tasks included control of an air conditioner, the operation of a radio, and the operation of a CD/MD, by means of a steering wheel mounted switch. The switch was either vertical or cross arrangement. In both-hands switch arrangement condition, the operation was carried out with two hands using both left vertical switch and right cross switch. In one-hand switch arrangement condition, the operation was carried out with only one hand using either left or right cross switch. The display was arranged in front of a participant. The display form was either left or right display. The viewing distance conditions were 60, 80, and 100cm. When the right display form was used, both one-hand (using only right cross switch) and two-hands arrangements (using both left vertical and right cross switch) were selected. When the left display form was used, both one-hand (using only left cross switch) and two-hand arrangements (using both left vertical and right cross switch) were selected. As predicted, age affected the performance measures (percentage correct, task completion time, and tracking error). The viewing distance also affected performance (percentage correct), Both display form and switch arrangement also affected performance (task completion time). Such results should be taken into account when designing display and control systems in man-vehicle systems

Design of vehicle instrumental panel for older adults - Effects of viewing distance, display from, and switch arrangement on secondary task performance -

The effects of age, viewing distance, arrangement of switches and display form on performance to design of display and control systems friendry to older adults were discussed. A dual-task experimemt was conducted in which the primary task was first-irder tracking. The secondary tasks included control of an air conditioner, the operation of a radio, and the operation of a CD/MD, by means of a steering wheel mounted swich. The switch was either vertical or cross arrangement. In both-hands switch arrangement condition, the operation was carried out with two hands using both left vertical switch and right cross switch. In one-hand swith arrangement condition, the operation was carried out with only one hand using either left or right cross switch. The display was arranged in front of a participant. The display form was either left or right display. The viewing distance conditions were 60, 80, and 100cm. When the right display form was used, both one-hand (using only right cross switch) were selected. When the left display form was used, both one-hand (using only left cross swith) and two-hand arrangements (using both left vertical and right cross switch) were selected. As predicted, age affected the performance measures ( percentage correct, task completion time, and tracking error). The viewing distance also affected performance (percentage correct), Both display form and switch arrangement also affected performance (task completion time). Such results should be taken into account when designing display and control systems in man-vehicle systems

Anomalies, Hawking Radiations and Regularity in Rotating Black Holes

This is an extended version of our previous letter hep-th/0602146. In this paper we consider rotating black holes and show that the flux of Hawking radiation can be determined by anomaly cancellation conditions and regularity requirement at the horizon. By using a dimensional reduction technique, each partial wave of quantum fields in a d=4 rotating black hole background can be interpreted as a (1+1)-dimensional charged field with a charge proportional to the azimuthal angular momentum m. From this and the analysis gr-qc/0502074, hep-th/0602146 on Hawking radiation from charged black holes, we show that the total flux of Hawking radiation from rotating black holes can be universally determined in terms of the values of anomalies at the horizon by demanding gauge invariance and general coordinate covariance at the quantum level. We also clarify our choice of boundary conditions and show that our results are consistent with the effective action approach where regularity at the future horizon and vanishing of ingoing modes at r=\infty are imposed (i.e. Unruh vacuum).Comment: 21 pages, minor corrections, added an appendix to summarize our notations for the Kaluza-Klein reductio