Gray codes for necklaces

AbstractAn n-bit necklace of density m is an equivalence class of binary strings having m 1's and n−m 0's with respect to the equivalence relation of rotation. An n-bit necklace is called prime if it has n distinct elements. Construction of a kind of Gray codes for prime necklaces and for general necklaces is presented here. That is, according to one algorithm, exactly one representative of each prime n-bit necklace of density m appears on the generated list, and successive representatives differ by a single transposition of a 0 and 1. The same is also true for general n-bit necklaces of density m according to a similar algorithm

How Do Scale Insects Settle into the Nests of Plant-Ants on Macaranga Myrmecophytes? Dispersal by Wind and Selection by Plant-Ants

This report elucidates the process of settlement by Coccus scale insects into Crematogaster plant-ant nests formed inside the hollow stems of a myrmecophytic species, Macaranga bancana, in a tropical rain forest. We collected wafting scale insect nymphs from the canopy using sticky traps and characterized the DNA sequence of the trapped nymphs. In addition, we experimentally introduced first-instar nymphs of both symbiotic and nonsymbiotic scale insects to M. bancana seedlings with newly formed plant-ant colonies. Nymphs of symbiotic species were generally carried by ants into their nests within a few minutes of introduction. Most nymphs of nonsymbiotic species were thrown to the ground by ants. Our results suggest that in Crematogaster-Macaranga myrmecophytism, symbiotic coccids disperse by wind onto host plant seedlings at the nymphal stage, and plant-ants actively carry the nymphs landing on seedlings into their nests in discrimination from nonsymbiotic scale insects.ArticleSOCIOBIOLOGY. 59(2):435-446 (2012)journal articl

Fundamental properties and durability of slope protection spray mortar reinforced with bamboo fibers

In order to enhance resistance against cracking and durability, short fibers such as steel and organic fibers have been conventionally mixed into spray mortar used for slope protection. In this research, fundamental properties of bamboo-fiber-mixed spray mortar were examined by laboratory tests. The mechanical properties of spray mortar containing bamboo fibers were examined under cyclic wet and dry conditions along with its resistance against freezing and thawing by a spray test. It was confirmed that 0.75% mixture of bamboo fibers in spray mortar most successfully improved mechanical properties and durability. These include adhesion strength to the base surface following exposure to cyclic wet/dry conditions and overall resistance against freezing and thawing. In addition, higher compressive strength and adhesion strength to the base surface were achieved by further mixing in vinylon fibers or fly ash in combination with bamboo fibers

Molecular phylogenetic affinities of Japanese Xenid and Stylopid Strepsipterans (Strepsiptera: Xenidae, Stylopidae) parasitizing wasps and bees

Strepsiptera is an insect order comprising 11 families with about 600 described obligate endoparasitoid species. In Strepsiptera, Xenidae and Stylopidae are the most diverse, Hymenoptera-parasitizing families. Here, we reconstructed a phylogenetic relationships of xenid and stylopid strepsipterans in Japan by using molecular data sets of the mitochondrial cytochrome oxidase subunit I gene (COL). The results of our molecular phylogenetic analysis agree well with the results of the latest morphologically based phylogenetic aspect. In addition, we identified two distinct mitochondrial lineages in X enosmoutoni, which parasitizes different host species.ArticleNew Entomologist. 61(1-2):15-20 (2012)journal articl

Spay Mortar Reinforced with Bamboo Fibers

In order to enhance resistance against cracking and durability, short fibers such as steel and organic fibers have been conventionally mixed into spray mortar used for slope protection. In this research, fundamental properties of bamboo-fiber-mixed spray mortar were examined by laboratory tests. The mechanical properties of spray mortar containing bamboo fibers were examined under cyclic wet and dry conditions along with its resistance against freezing and thawing by a spray test. It was confirmed that 0.75% mixture of bamboo fibers in spray mortar most successfully improved mechanical properties and durability. These include adhesion strength to the base surface following exposure to cyclic wet/dry conditions and overall resistance against freezing and thawing. In addition, higher compressive strength and adhesion strength to the base surface were achieved by further mixing in vinylon fibers or fly ash in combination with bamboo fibers

Phylogeography of the Coccus scale insects inhabiting myrmecophytic Macaranga plants in Southeast Asia

Comparative historical biogeography of multiple symbionts occurring on a common host taxa can shed light on the processes of symbiont diversification. Myrmecophytic Macaranga plants are associated with the obligate mutualistic symbionts: Crematogaster (subgenus Decacrema) ants and Coccus scale insects. We conduct phylogeographic analyses based on mitochondrial cytochrome oxidase I (COI) from 253 scale insects collected from 15 locations in Borneo, Malaya and Sumatra, to investigate the historical biogeography of the scales, and then to draw comparisons with that of the symbiotic, but independently dispersing, Decacrema ants which are not specific to different Coccus lineages. Despite the different mode of ancient diversification, reconstruction of ancestral area and age estimation on the Coccus phylogeny showed that the scales repeatedly migrated between Borneo and Malaya from Pliocene to Pleistocene, which is consistent with the Decacrema ants. Just as with the ants, the highest number of lineages in the scale insects was found in northern northwest Borneo, suggesting that these regions were rainforest refugia during cool dry phases of the Pleistocene. Overall, general congruence between the Plio-Pleistocene diversification histories of the symbiotic scales and ants suggests that they experienced a common history of extinction/migration despite their independent mode of dispersal and host-colonization.ArticlePopulation ecology. 52(1):137-146 (2010)journal articl

コウジンセイ セメント フクゴウ ザイリョウ オ モチイタ コンクリート コウゾウブツ ノ リハビリテーション シュホウ ノ カイハツ

Electrochemical corrosion control methods have been applied to concrete structures deteriorated by steel corrosion in concrete. By means of these methods, corrosion control effect can be expected, but the improvement of mechanical performances or prevention of dropping of concrete pieces can’t be gained. From such background, experimental investigation was carried out in order to clarify the possibility of a new electrochemical rehabilitation method, in which the ductile fiber reinforced cementitious composite bonding and covering the anode material on the concrete surface was used for improving the mechanical performances of the deteriorated structures. As the results of this study, bending strengthening effect was confirmed by the flexural bending test of reinforced concrete specimens applying the proposed method

AKARI IRC 2.5-5 um Spectroscopy of Infrared Galaxies over a Wide Luminosity Range

We present the result of a systematic infrared 2.5-5 um spectroscopic study of 22 nearby infrared galaxies over a wide infrared luminosity range (10 < log(L_IR / Lsun) < 13) obtained from AKARI Infrared Camera (IRC). The unique band of the AKARI IRC spectroscopy enables us to access both the 3.3 um polycyclic aromatic hydrocarbon (PAH) emission feature from star forming activity and the continuum of torus-dust emission heated by an active galactic nucleus (AGN). Applying our AGN diagnostics to the AKARI spectra, we discover 14 buried AGNs. The large fraction of buried AGNs suggests that AGN activity behind the dust is almost ubiquitous in ultra-/luminous infrared galaxies (U/LIRGs). We also find that both the fraction and energy contribution of buried AGNs increase with infrared luminosity from 10 < log(L_IR / Lsun) < 13, including normal infrared galaxies with log (L_IR / Lsun) < 11. The energy contribution from AGNs in the total infrared luminosity is only ~7% in LIRGs and ~20% in ULIRGs, suggesting that the majority of the infrared luminosity originates from starburst activity. Using the PAH emission, we investigate the luminosity relation between star formation and AGN. We find that these infrared galaxies exhibit higher star formation rates than optically selected Seyfert galaxies with the same AGN luminosities, implying that infrared galaxies could be an early evolutionary phase of AGN.Comment: 13 pages, 8 figures, accepted for publication in Ap

NMR study of electronic state in CePt3Si

In this article, we report the temperature dependence of spin-lattice relaxation rates at two Pt sites and one Si site in CePt3Si with a non-centrosymmetric structure center. 1/T1 for both Pt sites between 2 K and 300 K and 1/T1 of Si above 3 K might be explained by the contributions from the low-lying crystal-electric-field level and the quasiparticle due to the hybridization between the ground state and conduction electrons. Just below Tc no remarkable enhancement in 1/T1 was observed. The estimated value of superconducting gap is about 2Delta = 3kBTc.Comment: 2 pages with 2 EPS figures. uses phb-proc4-auth.cls. Accepted for publication in Physica

mtDNA phylogeny of Japanese ant crickets (Orthoptera : Myrmecophilidae): Diversification in host specificity and habitat use

Ant crickets (Myrmecophilidae, Orthoptera) are typical ant guests. Although ten species (all belonging to genus Myrmecophilus) have recently been described from Japan, their phylogeny and the extent of host specificity are not known. Here, we reconstruct mtDNA phylogeny of 48 individuals from six species to examine their host specificity, habitat use, and congruence of mtDNA lineages with the morphological species. The cytb phylogeny reveals seven well-supported lineages that in part do not corroborate morphological taxonomy. M. kubotai was split into two distinct mtDNA lineages which differ in their host specificity: one (lineage F) mainly parasitizes Tetramorium tsushimae (Myrmicinae) and the other (lineage E) parasitizes several species of Formicine ants. Five out of the seven Myrmecophilus lineages did not have significant host-specificity, although lineages C and the above mentioned F both preferably parasitized T tsushimae. Preference for light environment was significant for three cricket lineages. Although ant crickets arc not diverse in their morphology, these results demonstrate that they have diversified in host specificity and habitat use.ArticleSOCIOBIOLOGY. 52(3):553-565 (2008)journal articl