Studies of the oceanic and near-shore distributions of Pacific salmon, whose migrations typically span thousands of kilometres, have become increasingly valuable in the presence of climate change, increasing hatchery production and potentially high rates of bycatch in offshore fisheries. Genetics data offer considerable insights into both the migratory routes as well as the evolutionary histories of the species. However, these types of studies require extensive data sets from spawning populations originating from across the species' range. Single nucleotide polymorphisms (SNPs) have been particularly amenable for multinational applications because they are easily shared, require little interlaboratory standardization and can be assayed through increasingly efficient technologies. Here, we discuss the development of a data set for 114 populations of chum salmon through a collaboration among North American and Asian researchers, termed PacSNP. PacSNP is focused on developing the database and applying it to problems of international interest. A data set spanning the entire range of species provides a unique opportunity to examine patterns of variability, and we review issues associated with SNP development. We found evidence of ascertainment bias within the data set, variable linkage relationships between SNPs associated with ancestral groupings and outlier loci with alleles associated with latitude.

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This paper presents the topology optimization of a synchronous reluctance motor using the normalized Gaussian network. In the optimization, the average torque and iron loss are considered. In the resultant motor, the area of the rotor surface adjacent to the stator is found to be reduced when the weight for the iron loss is sufficiently large. On the other hand, large flux barriers present in the rotor when the average torque is maximized without considering the iron loss.

We examined the nucleotide sequences of 500 bp variable portion from the 5' end of mitochondrial (mt) DNA control region in about 500 individuals from 12 populations that were captured in 11 rivers, six in Hokkaido and five in Honshu, Japan. Comparison of the sequences showed 10 variable sites, defining a total of 12 haplotypes in the examined individuals. All the 12 haplotypes occurred in seven Hokkaido populations, whereas only six haplotypes were found in the five Honshu populations. Among these haplotypes, two were common in all the Hokkaido and Honshu populations. The AMOVA analysis inferred a genetic differentiation among three geographic regions, i.e. Hokkaido, Pacific Ocean coast in Honshu, and Japan Sea coast in Honshu. Haplotype diversity was higher in the populations of Hokkaido than those of Honshu, indicating a greater genetic variation in the Hokkaido than the Honshu populations. The estimates of pairwise population F ST suggested that the regional differentiation was mostly ascribed to the divergence between populations in Hokkaido and the Pacific coast in Honshu.

Variation at 14 microsatellite loci was surveyed in 26 chum salmon Oncorhynchus keta populations from Japan, one population from West Kamchatka and three populations from North America to determine population structure. Microsatellites were then applied to estimate stock composition of chum salmon in mixed-stock fisheries. The genetic differentiation index (Fst) over all populations and loci was 0.031, with individual locus values ranging from 0.010 to 0.081. Seven regional populations were observed in Japanese chum salmon, with late-run populations from the Pacific Coast of Honshu the most distinct. Japanese populations displayed greater genetic diversity than did those in North America. Transplantation history in some Japanese river populations influenced their present genetic characteristics. Analysis of simulated mixtures from fishery sampling suggested that accurate and precise regional estimates of stock composition should be produced when the microsatellites were used to estimate stock compositions. Stock compositions for a 2005 sample of maturing, migrating chum salmon off the north-west coast of Hokkaido near the border of the Sea of Japan and the Sea of Okhotsk indicated that this region may be a migration corridor for Hokkaido populations from the Sea of Japan coast. Microsatellites have the ability to provide fine-scale resolution of stock composition in Japanese coastal fisheries.