Coupled Map Modeling for Cloud Dynamics

A coupled map model for cloud dynamics is proposed, which consists of the successive operations of the physical processes; buoyancy, diffusion, viscosity, adiabatic expansion, fall of a droplet by gravity, descent flow dragged by the falling droplet, and advection. Through extensive simulations, the phases corresponding to stratus, cumulus, stratocumulus and cumulonimbus are found, with the change of the ground temperature and the moisture of the air. They are characterized by order parameters such as the cluster number, perimeter-to-area ratio of a cloud, and Kolmogorov-Sinai entropy.Comment: 9 pages, 4 figure, LaTeX, mpeg simulations available at http://aurora.elsip.hokudai.ac.jp

Polypeptide gels incorporating the exotic functional aromatic amino acid 4-amino-L-phenylalanine

High-molecular-weight polypeptides with functional aromatic side chains, poly(4-amino-l-phenylalanine), were prepared by the metal-initiated polymerization of the Nα-carboxyanhydride of the corresponding amino acid, which is a microbial derivative of phenylalanine

Bacterial Populations in the Beaufort Sea

Spatial and seasonal variation patterns were studied for bacterial populations in Beaufort Sea ice, water and sediment. Bacterial populations in the Beaufort Sea were found in concentrations as high as are found in temperate oceans. Bacterial populations, especially viable bacteria, were lower in surface water during winter than summer, but not in sediment. Beaufort Sea bacterial populations are mainly psychrotrophic and are clearly adapted to growth at low temperatures. Ice conditions appear to be important in determining levels of bacterial populations in water

Clinical Outcome of Laparoscopic Intersphincteric Resection Combined with Transanal Rectal Dissection for T3 Low Rectal Cancer in Patients with a Narrow Pelvis

Purpose. The purpose of this study was to analyze the safety and feasibility of laparoscopic intersphincteric resection (ISR) combined with transanal rectal dissection (TARD) for T3 low rectal cancer in a narrow pelvis. Methods. We studied 20 patients with a narrow pelvis of median body mass index 25.3 (16.9–31.2). Median observation period was 23.6 months (range 12.2–56.7). Results. Partial, subtotal, and total ISR was performed in 15, 1, and 4 patients, respectively. Median duration of TARD was 83 min (range 43–135). There were no major complications perioperatively or postoperatively. Surgical margins were histologically free of tumor cells in all patients, and there was no local recurrence. Excluding urgency, frequency of bowel movements, and incontinence status improved gradually after stoma closure. Conclusion. Laparoscopic ISR combined with TARD is technically feasible for selective T3 low rectal cancer in patients with a narrow pelvis

Noiseless Collective Motion out of Noisy Chaos

We consider the effect of microscopic external noise on the collective motion of a globally coupled map in fully desynchronized states. Without the external noise a macroscopic variable shows high-dimensional chaos distinguishable from random motion. With the increase of external noise intensity, the collective motion is successively simplified. The number of effective degrees of freedom in the collective motion is found to decrease as $-\log{\sigma^2}$ with the external noise variance $\sigma^2$. It is shown how the microscopic noise can suppress the number of degrees of freedom at a macroscopic level.Comment: 9 pages RevTex file and 4 postscript figure

High-Temperature Resistant Water-Soluble Polymers Derived From Exotic Amino Acids

© The Royal Society of Chemistry. High-performance water-soluble polymers have a wide range of applications from engineering materials to biomedical plastics. However, existing materials are either natural polymers that lack high thermostability or rigid synthetic polymers. Therefore, we design an amino acid-derived building block, 4,4′-diamino-α-truxillate dianion (4ATA2−), that induces water solubility in high-performance polymers. Polyimides containing 4ATA2− units are intrinsically water-soluble and are processed into films cast from an aqueous solution. The resulting polyimide films exhibit exceptional transparency and extremely high thermal stability. In addition, the films can be made insoluble in water by simple post-treatment using weak acid or multivalent metal ions such as calcium. The synthesized polyimide\u27s derived from bio-based resources are useful for yielding waterborne polymeric high-performance applications

Sample Size Effect of Magnetomechanical Response for Magnetic Elastomers by Using Permanent Magnets

The size effect of magnetomechanical response of chemically cross-linked disk shaped magnetic elastomers placed on a permanent magnet has been investigated by unidirectional compression tests. A cylindrical permanent magnet with a size of 35 mm in diameter and 15 mm in height was used to create the magnetic field. The magnetic field strength was approximately 420 mT at the center of the upper surface of the magnet. The diameter of the magnetoelastic polymer disks was varied from 14 mm to 35 mm, whereas the height was kept constant (5 mm) in the undeformed state. We have studied the influence of the disk diameter on the stress-strain behavior of the magnetoelastic in the presence and in the lack of magnetic field. It was found that the smallest magnetic elastomer with 14 mm diameter did not exhibit measurable magnetomechanical response due to magnetic field. On the opposite, the magnetic elastomers with diameters larger than 30 mm contracted in the direction parallel to the mechanical stress and largely elongated in the perpendicular direction. An explanation is put forward to interpret this size-dependent behavior by taking into account the nonuniform field distribution of magnetic field produced by the permanent magnet