Search

The effects of facilitation of sensation from the plantar foot surface on postural stabilization have been shown (Maki, Perry, Norrie, & Mcllroy, 1999). Therefore, changing the design of footwear h...

In this research, two-dimensional electrostatic Particle-In-Cell simulation techniques were used to study the dynamic formation of V-shaped potential structures in the upward current regions of auroral plasmas. These simulations imposed a non-constant but more realistic spatially varying external magnetic field that increases in magnitude as it nears the ionospheric regions. A characteristic of these simulations was that V-shaped potential structures became clearly visible within the expanding plasma as they evolved, with a transversely non-uniform converging perpendicular electric field being evident. These observations were consistent across a wide range of simulation sizes. The inclusion of dipole-like magnetic fields in the auroral region, though, the structure of V-shaped potential becomes more visible than in the simulations with a constant magnetic field.

The formation mechanism of operons remains controversial despite the proposal of many models. Although acquisition of genes from other species, horizontal gene transfer, is considered to occur, definitive concrete cases have been unavailable. It is desirable to select horizontally transferred genes reliably and examine their relationship to operons. We here developed a method to identify candidates of horizontally transferred genes based on minimization of gene cluster insertions/deletions. To select a benchmark set of positively horizontally transferred genes against which the candidate set can be appraised, we devised another procedure using intergenetic alignments. Comparison with the benchmark set of horizontally transferred genes demonstrated the absence of a significant number of false positives in the candidates, showing that the method identifies horizontally transferred genes with a high degree of confidence. Horizontally transferred genes constitute at least 5.5% of the genes in Escherichia, Shigella, and Salmonella and ~46% of which originate from other gamma-proteobacteria. Not only informational genes, but also operational genes (those involved in housekeeping) are horizontally transferred less frequently than expected. A gene-cluster analysis of Escherichia coli K-12 operons revealed that horizontal transfer produced four entire operons and expanded two operons, but deletion of intervening genes accounts for the formation of no operons. We propose that operons generally form by horizontal gene transfer. We further suggest that genes with related essential functions tend to reside in conserved operons, while genes in nonconserved operons generally confer slight advantage to the organisms and frequently undergo horizontal transfer and decay., Comment: 22 pages, 7 figures

Residue-wise contact order (RWCO) is a new kind of one-dimensional protein structures which represents the extent of long-range contacts. We have recently shown that a set of three types of one-dimensional structures (secondary structure, contact number, and RWCO) contains sufficient information for reconstructing the three-dimensional structure of proteins. Currently, there exist prediction methods for secondary structure and contact number from amino acid sequence, but none exists for RWCO. Also, the properties of amino acids that affect RWCO is not clearly understood. Here, we present a linear regression-based method to predict RWCO from amino acid sequence, and analyze the regression parameters to identify the properties that correlates with the RWCO. The present method achieves the significant correlation of 0.59 between the native and predicted RWCOs on average. An unusual feature of the RWCO prediction is the remarkably large optimal half window size of 26 residues. The regression parameters for the central and near-central residues of the local sequence segment highly correlate with those of the contact number prediction, and hence with hydrophobicity., Comment: 22 pages, 5 figures, 2 tables, manuscript submitted