We study the square-lattice three-state Potts model with the ferromagnetic next-nearest-neighbor coupling at finite temperature. Using the level-spectroscopy method, we numerically analyze the excitation spectrum of the transfer matrices and precisely determine the global phase diagram. Then we find that, contrary to a previous result based on the finite-size scaling, the massless region continues up to the decoupling point with Z3 × Z3 criticality in the antiferromagnetic region. We also check the universal relations among excitation levels to provide the reliability of our result.PACS numbers: 05.50.+q, 05.70.Jk, 64.60.Fr The concept of the Gaussian universality class provides a paradigm for the unified descriptions and understanding of the low-energy and long-distance properties of one-dimensional (1D) quantum and two-dimensional (2D) classical systems. Its representation is given by the free-boson fixed point model, and its criticality by the conformal field theory (CFT) with the central charge c = 1. The antiferromagnetic three-state Potts (AF3SP) model on the square lattice is one of those to exhibit the Gaussian criticality at zero temperature [1,2]. While the ground-state [1,2,3,4,5,6] and finite-temperature properties [7] were fully clarified, there still exists the considerable interest in its related extended-type models [3,8,9]. For instance, in [9], the emergence of the Z 2 and Z 3 criticalities were studied by introducing the AF3SP model with a staggered polarization field.In this paper we treat another model with a rather straightforward extension, i.e., the three-state Potts model with ferromagnetic next-nearest-neighbor coupling defined on the square lattice Λ, whose reduced HamiltonianThe first and the second sums run over all nearestneighbor and next-nearest-neighbor pairs, respectively, and the ternary variables σ j take the values 0,1,2 (j ∈ Λ). For the AF case (K 1 > 0), this model is thought to be in the same universality class as the ferromagnetic six-state clock (F6SC) model [10]. Theoretical investigations including numerical ones have been performed to clarify the global phase diagram [3,11,12]. However, its precise estimation is not available. This is mainly because two types of Berezinskii-Kosterlitz-Thouless (BKT) transitions take part in the phase diagram, and the numerical methods used so far were insufficient to treat the BKT transitions. For instance, the phenomenological renormalization-group (PRG) method has been frequently used for the determination of second-order transition points. However, as pointed out by several authors, it fails to estimate the BKT points [13]. Therefore, a new strategy should be employed. In investigations of 1D quantum systems, the level-spectroscopy method which takes logarithmic corrections into account has been used for precise estimates of the BKT points, and its possible application to the 2D classical system was also discussed [14]. Therefore, we shall reconsider this long-standing model (1) with a new methodological strategy in order to cla...

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Rheophilous Osmunda lancea often hybridizes with a dryland ally, Osmunda japonica, to produce O. x intermedia, forming zonation in riverbanks and the adjacent dryland along flooding frequency clines. This study examined the genetic structure of populations consisting of O. x intermedia and the two parental species by analyzing ten nuclear DNA markers [six cleaved amplified polymorphic sequence (CAPS) markers and three simple sequence repeat (SSR) markers developed from an expressed sequence tag (EST) library, and the sequence of the glyceraldehyde-3-phosphate dehydrogenase gene GapCp] and chloroplast DNA sequences. The results suggest that the nuclear genes of O. japonica and O. lancea are genetically differentiated despite shared polymorphism in their chloroplast DNA sequences. This discrepancy may be attributable to natural selection and recent introgression, although it is not evident if introgression occurs between O. japonica and O. lancea in the examined populations. Our findings of putative F2 hybrids in O. x intermedia support its partial reproducibility, and also suggest that formation of later-generation hybrids generates morphological variation in O. x intermedia. O. lancea plants collected from geographically distant localities were genetically very similar, and it is suggested that O. lancea originated monotopically.

The beta bind: Copper(I) binds to amyloid β‐peptide fragments (see structure) as a stable bis(histidine), two‐coordinate, near‐linear complex, even in the presence of potential additional ligands. As has been proposed or assumed in other studies, the copper(I)–peptide complexes react with dioxygen to form the reactive oxygen species H2O2, without the need for a third histidine ligand to promote the chemistry.

Eight microsatellite loci were identified and characterized for the endangered Machilus pseudokobu (Lauraceae), an endemic tree species of the Bonin Islands. The observed number of alleles at each locus ranged from 1 to 20 with an average of 6.2, and the expected heterozygosity ranged from 0.00 to 0.83 with an average of 0.47. All eight loci were screened in cross-amplification tests for two other endemic Machilus species that also inhabit the Bonin Islands. All loci were successfully amplified in these species.Keywords The Bonin (Ogasawara) Islands Á Cross-species amplification Á Genetic differentiation Á Lauraceae Á Machilus Á MicrosatelliteThe Bonin (Ogasawara) Islands comprise *20 oceanic islands located in the northwest Pacific Ocean. The flora of the Bonin Islands is characterized by a high degree of endemism and several examples of adaptive radiation (e.g., Crepidiastrum, Pittosporum, Symplocos; Ito 1998). Plants of the genus Machilus (Lauraceae) in the Bonin Islands are considered to represent an example of adaptive radiation (Ito et al. 1990). Three endemic species of Machilus are distributed in the Bonin Islands. Machilus pseudokobu. Koidz. occurs in the highly mesic forests in the central region of Chichijima Island, and is listed as endangered in the Japanese Red Data Book (Environment Agency of Japan 2007). It is difficult to distinguish M. pseudokobu. Koidz. from the other two Machilus species, M. kobu Maxim. and M. boninensis Koidz. based only on morphology, although their habitat preferences seem to be differentiated (Toyoda 2003). Thus, this species might be at an early stage of speciation by adaptive radiation. In this work, we developed eight microsatellite markers for the endangered M. pseudokobu in order to estimate its genetic diversity and to assess genetic differentiation among the Machilus species endemic to the Bonin Islands.Fresh leaves of M. pseudokobu were collected from Chichijima Island and genomic DNA was extracted using a DNeasy plant miniprep kit (Qiagen). Microsatellite loci were isolated using an improved technique for isolating codominant compound microsatellite markers (Lian et al. 2006). Briefly, DNA was digested with the blunt-end restriction enzymes SspI and BsrBI. The restriction fragments were then ligated with a specific blunt adaptor (consisting of the 48-mer: 5 0 -GTAATACGACTCACTATAGGGCACGCGT GGTCGACGGCCCGGGCTGGT-3 0 ; and an 8-mer with the 3 0 -end capped with an amino residue: 5 0 -ACCAGCCC-NH 2 -3 0 ) using a DNA ligation kit (Takara). The ligated fragments were treated with ddGTP using AmpliTaq Gold (Applied Biosystems) to block polymerase-catalyzed extension of the 8-mer adaptor strand. Fragments were amplified from the SspI and BsrBI DNA libraries using one of the compound SSR primers, (AC) 6 (AG) 5 or (AC) 6 (TC) 5 , and an adaptor primer (5 0 -CTATAGGGCACGCGTGGT-3 0 ). The amplified fragments were cloned using the Qiagen PCR Cloning plus kit (Qiagen) in accordance with the manufacturer's instructions. Insert-positive clones were amplified using forward and rev...