Search

We studied the effects of small-scale vegetation disturbances on biodiversity in an abandoned coppice forest in central Japan during 2004–2006. We assessed biodiversity by examining vegetation regeneration and by changes in the diversity and abundance of ground beetles after experimental manipulations including tree felling, vegetation clearing, and litter removal. Our experimental design was dictated by the need of producing only small disturbances; therefore we could not replicate plots. Instead, we used a repeated measures approach during three years to document the consistency of experimental effects. We found that the diversity of regenerating vegetation increased dramatically due to recruitment of many new species after clearing ground vegetation. Tree cutting caused strong environmental changes and affected vegetation regeneration rate but not diversity. Tree cutting also significantly increased the diversity of ground beetle species, while litter removal affected the abundance of ground beetles. Our results suggest that a sound conservation practice shall combine tree cutting with ground vegetation clearing and litter removal. Besides, conservation of abandoned forests may be based on low-intensity labor, including tree cutting on restricted areas. Finally, ground beetles appeared to be surprisingly sensitive to vegetation disturbance on a restricted area and thus can be suggested for monitoring such small-scale-disturbance-based conservation practices.

Flightlessness in insects is generally thought to have evolved due to changes in habitat environment or habitat isolation. Loss of flight may have changed reproductive traits in insects, but very few attempts have been made to assess evolutionary relationships between flight and reproductive traits in a group of related species. We elucidated the evolutionary history of flight loss and its relationship to evolution in food habit, relative reproductive investment, and egg size in the Silphinae (Coleoptera: Silphidae). Most flight-capable species in this group feed primarily on vertebrate carcasses, whereas flightless or flight-dimorphic species feed primarily on soil invertebrates. Ancestral state reconstruction based on our newly constructed molecular phylogenetic tree implied that flight muscle degeneration occurred twice in association with food habit changes from necrophagy to predatory, suggesting that flight loss could evolve independently from changes in the environmental circumstances per se. We found that total egg production increased with flight loss. We also found that egg size increased with decreased egg number following food habit changes in the lineage leading to predaceous species, suggesting that selection for larger larvae intensified with the food habit change. This correlated evolution has shaped diverse life-history patterns among extant species of Silphinae.

A macrocephalic pterostichine carabid, Pterostichus ishikawai Nemoto, endemic to the Korean Peninsula, is taxonomically revised based mainly on the membranous parts of the genitalia (male endophallus and female vagina). Two species are separated from P. ishikawai (type locality: Mount Taebaegsan) and newly described: P. ishikawaioides (type locality: Mount Sobaeksan) and P. jiricola (type locality: Mount Jirisan). Since comparative male genital morphology does not support monophyly for these three species, the two novel species should be treated as distinct species, not subspecies of P. ishikawai.

To reveal the role of diverged body size and genital morphology in reproductive isolation among closely related species, we examined patterns of, and factors limiting, introgressive hybridization between sympatric Ohomopterus ground beetles in central Japan using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences. We sampled 17 local assemblages that consisted of two to five species and estimated levels of interspecific gene flow using the genetic distance, D(A), and maximum-likelihood estimates of gene flow. Sharing of haplotypes or haplotype lineages was detected between six of seven species that occurred in the study areas, indicating mitochondrial introgression. The intensity and direction of mitochondrial gene flow were variable among species pairs. To determine the factors affecting introgression patterns, we tested the relationships between interspecific D(A) and five independent variables: difference in body size, difference in genital size, phylogenetic relatedness (nuclear gene sequence divergence), habitat difference, and species richness of the assemblage. Body and genital size differences contributed significantly to preventing gene flow. Thus, mechanical isolation mechanisms reduce the chance of introgressive hybridization between closely related species. Our results highlight the role of morphological divergence in speciation and assemblage formation processes through mechanical isolation.

The phylogeny and genital evolution of carabid beetles in the tribe Pterostichini, mainly the genus Pterostichus (Coleoptera: Carabidae), were studied using two nuclear gene sequences: wingless and 28SrDNA. Phylogenetic results suggest that the genera Molops, Poecilus, Stomis, Myas, Lesticus, and Trigonotoma and the subgenus Bothriopterus of the genus Pterostichus form basal lineages, with genus Molops sister to the rest of the tribe. The genus Pterostichus, with the exception of the subgenus Bothriopterus, was monophyletic and occupied more derived lineages. Examinations of the membranous parts of the genitalia (male endophallus and female spermatheca) revealed that endophalli and spermathecae are classified into four and five types, respectively. Reconstructions of genital character evolution on the trees obtained suggest that the ancestor of Pterostichini had a straight endophallus and a short cylindrical spermatheca and that the elaborated genitalia seen in some species evolved in more derive...

Even in species which are distinguishable by mainly internal structures or molecular data (e.g., cryptic species), external morphology could be useful for species identification. This paper describes the morphology and distribution of two species in Poecilus ‘samurai’ (Coleoptera: Carabidae) and tested the utility of external morphometrics for identification of cryptic species. The examination of the membranous parts of genitalia revealed that P. ‘samurai’ is composed of two externally similar species: P. sp. 1 (Hokkaido and Honshu) and P. sp. 2 (Hokkaido, Kyushu, Russia and Korea). With a focus on the identification of individuals from Hokkaido where the two species sympatrically occur, discriminant analyses based on measurements of ten external characteristics were performed between P. sp. 1 (Hokkaido) and P. sp. 2 (Hokkaido), and between P. sp. 1 (Hokkaido and Honshu) and P. sp. 2 (Hokkaido). In the former, all individuals were correctly classified into their own species, whereas in the latter, some individuals were incorrectly classified, suggesting that discriminant analyses using focal populations are more effective. A morphological phylogeny of five Poecilus species (including sp. 1 and 2) was provided, and the distribution pattern in the Japanese Archipelago was discussed.

Two new carabid beetle species, Pristosia impunctata and P. latistoma (Coleoptera: Carabidae), are described from South Korea. The phylogenetic relationships among five Korean and Japanese Pristosia species are reconstructed based on a cladistic analysis of 29 morphological characters.

Tensile tests were conducted at temperatures from 473 to 623 K on a two-phase Mg–9.5 wt.% Li–1.0 wt.% Zn alloy with an initial lamellar structure. It is shown that the alloy exhibits a quasi-superplastic behavior with a maximum recorded elongation of 290% at 523 K when testing with an initial strain rate of 1.0 × 10?4 s?1. The experiments give a strain rate sensitivity of 0.33 and an activation energy of 92 kJ mol?1. Metallographic inspection after failure revealed the occurrence of extensive internal cavitation and quantitative measurements were undertaken to determine the shapes and sizes of these internal cavities at two different testing temperatures. It is shown that the results suggest a transition with increasing strain from cavity growth by diffusion to growth controlled by plastic flow in the surrounding crystalline matrix.

We determined the flight capabilities and feeding habits of adults of nine silphine beetle species and illustrated their relationship. We examined the silphine beetles for the presence or absence of flight muscles and estimated their feeding habits by comparing the carbon and nitrogen stable isotope ratios for them with those of necrophagous nicrophorine species and carnivorous carabine species. Three species (Silpha longicornis, S. perforata and Phosphuga atrata) completely lacked individuals with flight muscles, and one species (Eusilpha japonica) showed flight muscle dimorphism. Stable isotope analysis suggested that these species were carnivores, mainly feeding on soil invertebrates. Most flight species showed higher isotopic ratios than the flightless species. Some of them have isotopic ratios close to those of the nicrophorine species, suggesting that these species mainly feed on vertebrate carcasses. Flightless silphine species would have limited ability to search for patchy and unpredictable carcass resources. Further studies are necessary to understand the adaptive evolution of flight capability and the feeding habits in this group.

The present study was designed to evaluate the interaction between disequilibrium and irregular stepping components of ataxic gait. For this purpose, we compared the walking patterns of patients with cerebellar dominant multiple system atrophy (MSAc, n = 8), spinocerebellar ataxia type 6 (SCA6, n = 4) and 16q-linked autosomal dominant cortical cerebellar atrophy (16q-linked ADCA, n = 6), and 6 normal subjects, by measuring toe and heel plantar pressures. In healthy subjects, the heel contacted the floor at step-in followed by an immediate shift of the center of pressure (COP) to the contacted leg. In ataxic gait, however, both the heel and toes simultaneously contacted the floor and the disappearance of the immediate shift of the COP was noted. These changes appeared to be nonspecific compensations for the instability. Examination of two parameters of ataxia-specific changes showed that prolongation of the double support period was associated with proportionate increase in the coefficients of variance of the plantar pressures and the step lengths on walking of patients with SCA6, but not those with MSAc and 16q-linked ADCA. Our results suggest that disequilibrium and irregularity are two separate and independent components of cerebellar ataxic gait.

The shapes and lengths of copulatory pieces and vaginal appendices of the carabid beetle subgenus Ohomopterus (genus Carabus) vary among species. In Japan, the species in the group with a medium body size (C. yaconinus, C. iwawakianus, C. maiyasanus, C. uenoi, C. arrowianus, C. esakii, and C. insulicola) are usually allopatric or parapatric, except at Mt Kongosan, where C. uenoi, C. iwawakianus, and C. yaconinus are sympatrically distributed. The degree of premating isolation by mate preference was high between sympatric populations, irrespective of the genetic distance between them. However, premating isolation was absent between parapatric populations. The degree of premating isolation for allopatric populations spanned a wide range of isolation values. Thus, mate discrimination by males seems to have evolved mostly between sympatric pairs. These results suggest two hypotheses. First, premating isolation has evolved through reinforcement or through reproductive character displacement after sympatric contact. Second, premating isolation has evolved in allopatry, and as a result of premating isolation, the species can coexist in sympatry. We also examined the degree of mechanical isolation between C. uenoi and C. iwawakianus (a sympatric pair), which have a very large difference in the length of the copulatory piece. The insertion success was low and only one female produced viable offspring among 15 crosses; however, death in females due to copulation was rare. For sympatric matings between C. uenoi and C. iwawakianus, a large difference in the genital size might reduce the gene flow with small mating costs. Gene flow that was significantly reduced by genital difference might cause either the evolution of premating isolation through reinforcement/reproductive character displacement or through the maintenance of a high degree of premating isolation following sympatric contact. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87, 145–154.

The dependence of α-Fe particle size on the formation of Fe16N2 with giant magnetization was studied by nitriding α-Fe fine particles below 200°C with different particle size (60nm, 120nm, 300nm) derived from α-Fe2O3. Nitridation of the largest α-Fe particle (300nm) was difficult to obtain Fe16N2. Mixtures of Fe16N2 with unreacted α-Fe and Fe4N were obtained by nitridation of the smaller α-Fe particles (120nm, 60nm). The nitridation process was most controllable for α-Fe particle of 120nm to obtain the most amount of Fe16N2. Magnetization was not enhanced by the formation of Fe16N2 probably due to disordering of the nitrogen introduced into Fe lattice. Monodispersed α-Fe particles could be obtained by thermal decomposition of Fe(CO)5 in octylether. Their size could be controlled with the amount of added stabilizer in the ether. They could be nitrided to Fe16N2 in low temperature nitridation.

Pterostichus thunbergi Morawitz and its related species of Japan are revised based on the structure of membranous parts of their genitalia for the first time, under the name of the thunbergi species group. This species group is monophyletic and is placed in the subgenus Morphnosoma Lutshnik. The monotypic subgenus Moritapterus Berlov, erected for P. thunbergi, is synonymized with Morphnosoma. Comparative study of the endophallus revealed that P. thunbergi michinoku Nakane is a junior synonym of P. habui and that four species should be recognized in this group. Three of them are sympatric with P. thunbergi and one of them, Pterostichus (Morphnosoma) robustistylis, is described as a new species. Molecular phylogeny based on the COI gene (mitochondrial [mt]DNA) supported its independence as a distinct species. The resultant trees of mtDNA and comparative study of morphology revealed that P. thunbergi is probably non-monophyletic. In the present study we suggest the presence of further cryptic species of Morphnosoma in Japan.

Populations of forms intermediate between Carabus (Ohomopterus) insulicola and Carabus (Ohomopterus) arrowianus occur at the boundaries between the two species in the Kiso Valley, Nagano Prefecture, central Honshu, Japan. Morphological and mitochondrial DNA analyses revealed that these populations are derived from a hybrid swarm established as a result of secondary contact between the two species. A similar hybrid swarm has been reported in the Ina Valley, an adjacent river basin separated by the Kiso Mountain Range, where the two species are distributed parapatrically. The hybrid swarm individuals in the two valleys show parallelism in the morphological evolution of the male genitalia upon secondary contact and subsequent formation of hybrid swarms between the two Carabus species.

We investigated the species status and intraspecific phylogeography in South Korea of two ground beetle species, Coptolabrus jankowskii and Coptolabrus smaragdinus (Coleoptera: Carabidae), using statistical parsimony networks and nested clade analyses based on sequences from the mitochondrial cytochrome oxidase subunit I (COI) and nuclear phosphoenolpyruvate carboxykinase (PepCK) and wingless (Wg) genes. Although traditional parsimony tree construction generally failed to resolve interspecific relationships and construct biologically meaningful genealogies, analysis using statistical parsimony networks yielded statistically significant inter- and intraspecific genealogical structures. We found that although these two species represent a notable case of trans-species polymorphisms in both mitochondrial and nuclear gene sequences, their status as separate species was evidenced by the nonrandom association between species and nested clades at various nesting levels. The exceptional occurrence of shared identical or very similar COI sequences was considered to be the result of introgressive hybridization. In addition, range expansion and fragmentation events across the Korean Peninsula and adjacent islands were inferred from nested clade phylogeographical analyses. The COI gene revealed the geographical divergence of major eastern and western clades and historical biogeographical events within each major clade, whereas the nuclear PepCK gene, which did not reveal corresponding east– west clades, indicated past fragmentation and range expansion across wide areas that may have been the result of older biogeographical events. Thus, phylogeographical inferences drawn from analyses of mitochondrial and nuclear genes can reveal different and potentially complementary information about phylogeographical processes.

A flightless carabid beetle, Pterostichus bellatrix (Tschitscherine, 1895), which is endemic to the Korean Peninsula, had been thought to comprise two subspecies: the nominotypical subspecies distributed in northern and central parts of the peninsula, and the subspecies P. bellatrix togyusanus Park and Kwon, 1996 , distributed in the southern part of the peninsula. A recent study upgraded these two subspecies to species level, but no convincing evidence was provided for this taxonomic change. Our comparative morphology of external and male genital characters revealed that these two species are paraphyletic with respect to Pterostichus syleus Kirschenhofer, 1997 , which was described from Liaoning Province, China. Thus, separate species status of P. bellatrix and P. togyusanus was confirmed phylogenetically. Although P. togyusanus has only been known from the type locality, Mt. Deogyusan, we newly record this species from Mt. Jirisan, a mountain located south of the known locality. A revised key to species of the Pterostichus opacipennis species group (= the subgenus Koreonialoe (s. str.) Park and Kwon, 1996 ), which now includes 14 species, is also provided.

The sugi bark borer, Semanotus japonicus, occurs naturally in Honshu, Shikoku, Sado Is., Oki Is., and Yaku Is. in Japan, and its main host tree is the Japanese cedar, Cryptomeria japonica. Because of a correspondence between the present distribution of geographical variation in the borer and the refugia of the Japanese cedar during the last fullglacial period, isolation of the cedar is thought to have caused differentiation in the borer between local populations. In this study, we used morphological information to elucidate the geographical differentiation of S. japonicus populations. Multivariate analyses were performed based on ten morphological characters for ten populations. Populations between the Pacific coast side and the Wakasa Bay area showed remarkable variation in morphological characters. Because the distribution of the refugia of the cedar coincided with the patterns of morphological variations in S. japonicus, it is suggested that the geographical structure of the present S. japonicus population was caused by isolation during the last glacial period. While vicariance is no longer a factor with the expansion of C. japonica’s distribution, its past effects may have been important enough to influence the present genetic structure of S. japonicus.

The sugi bark borer, Semanotus japonicus, occurs naturally in Honshu, Shikoku, Sado Is., Oki Is., and Yaku Is. in Japan, and its main host tree is the Japanese cedar, Cryptomeria japonica. Because the geographical structure of the morphological characters largely corresponds to the sites of the glacial refugia and the post-Pleistocene dispersal route of the Japanese cedar, the history of the cedar was postulated to have shaped the genetic population structure in the borer. In this study, we used partial sequences from mitochondrial DNA genes, the COI, tRNALeu-UUR and COII to elucidate processes in the geographical structuring of S. japonicus populations. Ten haplotypes were revealed among 52 individuals from four populations that ranged from Iwate to Ehime prefectures. The geographical distribution of these haplotypes was highly structured. Two distinct lineages were detected, which probably represented the Pacific coastal and the Japan Sea side lineages, from the neighbour-joining method and haplotype networking. As haplotypes of both Pacific and Japan Sea lineages were found in the Iwate population, a second contact might have occurred in the Tohoku area. These results suggested that the present genetic structure of S. japonicus was determined by the host's past history.

A new measurement method of residual stress distributions in the depth direction was proposed. In this method, the residual stress distribution is obtained from three kinds of diffraction data by the following process. First, a temporary residual stress distribution in the depth direction is assumed. Theoretical 2θ-sin 2 ψ diagrams for each wavelength are calculated by the cos ψ method which was developed by one of the authors. The total difference between the theoretical and experimental values of the diffraction angle in 2θ-sin 2 ψ diagrams is calculated. Minimizing the error using the quasi-Newton method, the assumed stress distribution was optimized. Finally, the optimized 2θ-sin 2 ψ diagrams for each diffraction plane and the detailed stress distribution are determined. The proposed method was applied to shot-peened surfaces and fatigue fracture surfaces of steel. The synchrotron radiation (SR) system at the Photon Factory (PF) of the High Energy Accelerator Research Organization, KEK, in Tsukuba, Japan was used as the X-ray source. Measured diffractions were 211, 220 and 310 of α-Fe. Wavelengths used to measure each diffraction were 0.228, 0.197 and 0.176 nm respectively. We adopted the constant diffraction angle of 2θ=154 deg for all diffraction planes tested. The range of X-ray tilt angle ψ was 0-65 deg. The depth profile of the residual stress in a thin layer near the shot-peened surface was estimated using the proposed method. The experimental diagrams of 2θ-sin 2 ψ for the estimated depth profile of residual stress coincide well with calculated one for all diffraction measured in this study.

This paper investigates the effects of the informal school curriculum (hidden curriculum) on subsequent preference formation. The estimation results using Japanese data show that the hidden curriculum at public elementary schools varies widely from place to place, and is associated with preference formation. In particular, those who have experienced "participatory and cooperative learning" practices are more likely to be altruistic, cooperative, reciprocal, and have national pride. In contrast, the influence of educational practices emphasizing "anti-competition" is negatively associated with these attributes. Robustness checks also show that our estimates are less likely to be biased due to omitted variables or reverse causality. These findings imply that elementary school education, as a place for early socialization, plays a role in the formation of social preferences.

Geographic variation and interspecific differentiation in body size (body length) were analyzed for 15 species of the carabid subgenus Ohomopterus (genus Carabus; Coleoptera, Carabidae) in Japan. Local species assemblages of this subgenus consist of up to 5 species of different size classes. These beetles exhibited sexual dimorphism in body size where females are larger than males, except Carabus uenoi, in which the male and female sizes were equivalent, possibly because of the exaggerated male genitalia. In 9 of 15 species, there was a positive correlation between mean body size and annual mean temperature of habitat, representing the converse of Bergmann's rule. However, in some cases this correlation does not hold over the range of a species because of regional differences. When allopatric and sympatric populations were compared, allopatric populations of Carabus albrechti and C. japonicus had larger bodies than sympatric populations. These intraspecific differences may have resulted from character displacement. In each local assemblage with 2 or more species, there was little interspecific overlap of body size, although the body size ratio between two species with adjacent body sizes seldom showed strict constancy. The mean size ratio between 2 adjacent species in an assemblage was reduced with the number of species, whereas the size ratio of the largest to smallest species in an assemblage increased with the number of species (i.e., the expansion of body size range). These results indicate that the body size of Ohomopterus species may have evolved in response to both climatic conditions and interspecific interactions. Because each species or species group represents the same size class over the distribution range and similar-sized species are parapatric or allopatric, the interspecific segregation in body size in local assemblages may have resulted mainly from a size assortment process during colonization.

Natural hybridization among wingless carabid beetles of the subgenusOhomopterus (Carabidae, genusCarabus) is reviewed, and its significance in the evolution of this subgenus discussed. Natural hybridization occurs between parapatric species of similar size. Two case studies of natural hybridization suggest that natural hybridization could have affected the evolution of this subgenus in different ways. When there is a large difference in genital morphology between hybridizing species, interspecific copulation often results in genital injuries that causes mortality of copulating individuals, and hence reduces the fitness of hybridizing individuals greatly. In such a case, hybridization may be effective in maintaining the parapatric distribution of the two species, and in the long term, may promote reinforcement selection for traits which are effective in prezygotic reproductive isolation. When the morphological difference in genitalia is not so large as to cause genital injury, a hybrid population may be established at the intermediate zone between two parental species, provided that the immigration rates of the two species into the intermediate zone are small. Thus, natural hybridization may have contributed to both divergence and reticulate evolution in this subgenus.

We demonstrate experimentally that differences in genital characters impose a direct cost of interspecific copulation on two closely related carabid species, Carabus (Ohomopterus) maiyasanus and C. (O.) iwawakianus, that share a narrow hybrid zone. Males of both species attempted copulation indiscriminately between conspecific and heterospecific females. Females experiencing heterospecific mating often suffered mortality due to rupture of their vaginal membranes. Those without fatal injury laid eggs which developed into F1 adults, but the fertilization rate was much lower than for intraspecific pairs. Males of C. maiyasanus, but not C. iwawakianus, often had broken genital parts (copulatory pieces) following interspecific copulations, which may prevent normal copulation in subsequent matings. Because of female mortality and low fertilization rate, the estimated fitness cost of interspecific mating was very large in terms of the reduction in the number of offspring (hatching larvae) for both sexes and both species. Thus, genital lock-and-key appears to exert significant selection against hybridization in the hybrid zone of these carabid beetles.

The purpose of the present work is to improve the elongation of the b.c.c. single phase Mg-Li-Al alloys by the addition of the fourth alloying element. As the fourth alloying element, the authors have chosen copper because it is slightly soluble in magnesium and is expected to act as the nucleation sites for precipitates in this alloy; many nucleation sites for the precipitates are introduced into the Mg-Li-Al alloy so that the precipitates particles are finely and uniformly dispersed. Hence, it is expected that a good combination between high tensile strength and high elongation is obtained. The authors have investigated the relationship between aging behavior and the mechanical properties of the Mg-37.5 at%Li-0.7 at%Al-0.4 at5 Cu alloy.

This paper presents empirical evidence concerning effects of cultural differences on parents' attitudes toward children from unique U.S. and Japanese survey data. These data sets have been collected by Osaka University, and contain questions concerning worldviews and religions, hypothetical questions about parental behavior, and questions about socioeconomic variables. The data show that U.S. parents tend to be tougher than Japanese parents toward young children. Our evidence suggests that contents of worldview beliefs held by parents affect parents' attitudes toward children. Our empirical evidence also indicates that people who are confident about worldview beliefs tend to show tough attitudes toward their children. Because U.S. parents are much more confident than Japanese parents in worldview beliefs on the average, this cultural difference helps explain a substantial portion of the difference in parental attitudes between U.S. and Japanese parents.

Tensile tests were performed between 293–573 K in order to investigate the mechanical properties of cast and extruded Mg-Si alloys. For the cast materials, Mg-high Si (⩾ 10 wt%) alloys showed lower values of the highest tensile strength at temperatures up to 373 K, as compared to pure Mg and Mg-low Si (

The alloys Mg–6Si and Mg–4Si–4Zn (wt-%) were extruded at 573 K and the mechanical properties investigated by tensile testing at strain rates from 2 × 10−5 to 2 × 10−2s−1 and at temperatures in the range 673–773 K. The Mg–Si alloy behaved as M type at any given strain rate. The Mg–Si–Zn alloy behaved as A type at strain rates above 2 × 10−4s−1. The activation energy for the deformation process was higher than those for lattice self diffusion and for the chemical interdiffusion of Zn in Mg. This is probably related to the cross-slip of dislocations. For the Mg–Si–Zn alloy, superplastic behaviour was found at strain rates below 2 × 10−4s−1. The dominant superplastic deformation process is likely to be grain boundary diffusion controlled grain boundary sliding.MST/3192

The Mg-Mg2Si composite processed from rapidly solidified ribbons exhibited high strength of about 500 MPa at room temperature and superplastic behavior at high strain rates of 10−1 ~ 1 s−1 at 773 K. The high strain rate superplasticity is attributed to the very small grain size of about 1 μm.

Relationship between extrusion ratio and mechanical properties was examined on hot extruded machined-chip of AZ91 magnesium alloy so as to establish a technology to recycle magnesium alloys from machined chips by a simple method. High tensile strength was achieved when the machined chips were extruded at an extrusion ratio of 4.9 or more compared with a material extruded at a ratio of 1.8 or a hot pressed material because the machined chips were completely bonded to each other and microstructure such as grains and Al12Mg17 precipitates was refined by severe plastic deformation of the machined chips during hot extrusion. A material extruded at a ratio of 44 showed the highest tensile strength of 373MPa, while the strength decreased when the extrusion ratio increased up to 100 owing to recovery of the microstructure. On the other hand, fracture strain increased with increasing extrusion ratio; 7.3% or more fracture strain was achieved especially when the extrusion ratios were 44 or 100 because initiation and growth of cracks were suppressed by the refined microstructure.

Hot extrusion has been carried out at 573, 673 and 753 K on machined chips of an AZ91 magnesium alloy and mechanical properties of the extrusions have been investigated. The extrusions processed from machined chips showed a good combination of high ultimate tensile strengths of 320-410 MPa, high 0.2% proof stresses of 220-300 MPa and elongations to failure of 5 ∼ 12% at room temperature. Grain refinement and dispersion of oxide layers by hot extrusion were responsible for the good mechanical properties at room temperature. Also the extrusions processed from machined chips at 573 and 673 K showed superplastic behavior at 573 K, though the elongations of the extrusions processed from machined chips were lower than those of the extrusion processed from the cast ingot.

Mechanical properties and microstructure have been investigated in as-cast and as-extruded materials for a Mg-Si-Al alloy (Mg-12.6 wt% Si-4.2 wt% Al). Hot extrusion caused grain refinement, refinement and homogeneous distribution of Mg2Si particles free of particle-matrix interfacial cracks and therefore the mechanical properties were improved.

Using an original dataset, we investigate the determinants of individual preferences for income redistribution in India. Our results suggest that the preferences of Indians for income redistribution are not really based on monetary motives. We found that people who have had negative experiences or perceptions of their future economic situation favour greater redistribution and people in a good economic (past, current, and future) condition also show a favourable attitude towards redistribution. In short, economically advantaged people seem to behave in a socially responsible manner. This 'noblesse oblige' effect can be explained mostly by prevalent social and religious beliefs.

A taxonomic redefinition of Silpha longicornis Portevin, 1926 is presented and the lectotype of S. longicornis is designated. Silpha yamatona Kono, 1929 and Silpha imitator Shibata, 1969 are synonymized with S. longicornis based on examination of their type specimens and the geographic pattern of mtDNA CO1 region collected from representative localities in Japan, including their type localities. A key for the northeast Asian members of the Silpha carinata group is presented, and the geographic distribution, life cycle, microhabitat, and feeding biology of S. longicornis are summarized. Body size and elytral colors and sculptures are influenced by climatic conditions, and this morphological variation conformed to Gloger’s rule and the converse of Bergmann’s rule.

The life cycle/permanent income hypothesis (LCPIH) makes two postulates: people behave with rational expectations, and people do not have self-control problems. If either or both of these postulates do not apply, we cannot obtain a testable implication of the LCPIH. We use Japanese panel data that include responses to self-reported and retrospective questions to elicit individual characteristics such as forward-looking behavior, experience of self-control problems, and use of commitment devices to overcome self-control problems. First, we test the rational expectations hypothesis and find that it holds for the whole sample. We then test the LCPIH implication and find that consumption does not change in response to expected income changes, which we restrict to fit the assumptions of the LCPIH. This result indicates that the LCPIH is a convincing model to account for the behavior of rational consumers who have rational expectations and no self-control problems. Our results also imply that responses to self-reported and retrospective questions are not meaningless when eliciting information on household characteristics.

In the carabid genus Carabus subgenus Ohomopterus, diverged body size and genital morphology serve as mechanical reproductive barriers. To elucidate the diverging process of body and genital sizes in Carabus arrowianus, which exhibits marked morphological diversity among geographical populations and may represent an early stage of speciation, we analysed a mitochondrial gene sequence for 1051 individuals from 63 populations and male morphology for 359 individuals from 47 populations. Two discrete morphological groups segregated by geographical barriers were distinguished, one of which possessed smaller bodies and shorter genitalia (S group) than the other (L group), which exhibited larger bodies and exaggerated genitalia. Genetic divergence between the two groups was significant but not large. Phylogeographical and population genetic analyses indicated that the L group was derived from the S group, and a coalescent simulation revealed that the two groups diverged during the latest middle Pleistocene (0.13 million years ago), with a much larger effective population size in the L group than the S group. Because the body size divergence could not be explained by adaptation to climatic conditions and genital morphology is considered to be subject to sexual selection, we postulated that a population division and colonization in favourable habitats caused by the Pleistocene climatic and geographical change might facilitate natural and sexual selection for enlarged body and genital sizes in the L group.

The purpose of this paper is to estimate the degree of competition of consumer loan industry in Japan utilizing responses to a questionnaire survey conducted by Japan Consumer Finance Association. Estimating the cost function, we found that the industry is characterized by large scale economies. Estimation of Lerner index, H-statistics, degree of noncompetition, and degree of collusion reveals that consumer loan market is highly monopolistic. Consumer loan companies answered to a question that they commit neither interest rate competition nor quantity competition through extending branch-networks. We further investigated the reason why consumer loan market is monopolistic. Market for new customers is characterized by informational asymmetry, usury law, and hyperbolic discounting of borrowers, which makes the market monopolistic. Meanwhile, market for incumbent customers is monopolistic because they would not search for new lenders to avoid switching costs. These findings may be useful to draft new regulations on the industry.

Based on the structures of the male genitalia, the subgenus Petrophilus Chaudoir is redefined, and five subgenera, viz., Euryperis Motschulsky, Morphnosoma Lutshnik, Euferonia Casey, Feroperis Lafer, and Moritapterus Berlov, are synonymized with Petrophilus. Phylogenetic analyses based on eighteen morphological characters revealed that the subgenus Petrophilus is monophyletic, whereas most traditional subgenera synonymized with Petrophilus are non-monophyletic. Pterostichus (Petrophilus) tuberifer Sasakawa, sp. nov., a sympatric species with P. thunbergi Morawitz, is described from Japan.

We analyzed the intraspecific gene genealogies of three Leptocarabus ground beetle species ( L. seishinensis , L. semiopacus , L. koreanus ) in South Korea using sequence data from the mitochondrial cytochrome oxidase subunit I (COI) and nuclear 28S rRNA (28S) genes, and compared phylogeographical patterns among the species. The COI data detected significant genetic differentiation among local populations of all three species, whereas the 28S data showed genetic differentiation only for L. seishinensis . The clearest differentiation of L. seishinensis among local populations was between the northern and southern regions in the COI clades, whereas the 28S clade, which likely indicates relatively ancient events, revealed a range expansion across the northern and southern regions. Leptocarabus semiopacus had the most shallow differentiation of the COI haplotypes, and some clades occurred across the northern and southern regions. In L. koreanus , four diverged COI clades occurred in different regions, with partial overlaps. We discuss the difference in phylogeographical patterns among these Leptocarabus species, as well as between these and other groups of carabid beetles in South Korea.