General Rule and Materials Design of Negative Effective U System for High-T_c Superconductivity

Based on the microscopic mechanisms of (1) charge-excitation-induced negative effective U in s^1 or d^9 electronic configurations, and (2) exchange-correlation-induced negative effective U in d^4 or d^6 electronic configurations, we propose a general rule and materials design of negative effective U system in itinerant (ionic and metallic) system for the realization of high-T_c superconductors. We design a T_c-enhancing layer (or clusters) of charge-excitation-induced negative effective $U$ connecting the superconducting layers for the realistic systems.Comment: 11 pages, 1 figures, 2 tables, APEX in printin

Seasonal Occurrence of Large-sized Black Porgy, Acanthopagrus schlegelii in an Intertidal Short-neck Clam Fishery Ground in Hiroshima Bay, Japan

広島湾最大のアサリ漁獲量のある漁場である広島県廿日市市の前潟干潟において，2003年2月から2004年1月の1年間にわたり刺網による調査を行い，アサリ食害魚種である大型のクロダイAcanthopagrus schlegeliiの出現状況を明らかにした。9種73個体の魚類が採集され，クロダイ（23.6～48.5cm TL）が全個体数の79％を占める優占種であった。クロダイの月別CPUE（個体数/300m/回）は0～18.8の範囲であり，6月末に急上昇し，7月末には最高値の18.8を示し，8月末，9月末も高値を示した。本種は，初夏から秋季の6月末～10月末の5ヶ月間に多く出現すること，この間は，体サイズにかかわらず干潟域を利用することが明らかになった。Black porgy, Acanthopagrus schlegelii (Family: Sparidae), is a commercially important fish in Japan. This species is known as a major predator of the short-neck clam Ruditapes philippinarum in tidal flats. Seasonal occurrence of large fishes such as the porgy was investigated from February 2003 to January 2004 at the Maegata tidal flat, which has the largest catch of short-neck clam in Hiroshima Bay, western Seto Inland Sea. As a result, 73 individuals from nine species were collected by monthly gill net sampling. A. schlegelii, 23.6-48.5 cm total length was the dominant species and accounted for 79% of the total individuals. The catch per unit effort (CPUE: number of fish caught/300 m of netting) of the porgy was 0–18.8. The CPUE rapidly increased in late June. In late July, it reached 18.8, the highest annual value, after which the CPUE maintained high values during late August and late September. From late November values were low (0-3.0) again. These results indicate that large-sized A. schlegelii occur seasonally in the tidal flats from late June to late October

Report on Distribution and Spawning of Small-scale Sillago, Sillago parvisquamis (family Sillaginidae), Based on Specimens from Yamaguchi Bay in Western Seto Inland Sea, Japan. <Article>

瀬戸内海山口湾で2005 ～ 2008 年に,絶滅危惧種アオギスSillago parvisquamis 8 標本(SP-YB1 ～ 8)を採集した。全長226.5 ～ 320.1mm,体長197.7 ～ 281.0mm,いずれも雌で,年齢はSP-YB1 ～ 6 が1才,SP-YB7 が3才,およびSP-YB8 は4才で,全個体が2004年級であった。卵巣の組織学的検討より,SP-YB1 ～ 7 では,最も発達した正常な卵母細胞は第三次卵黄球期か胚胞移動期で,排卵後濾胞細胞を有し,活発な産卵活動が確認された。釣りCPUE(個体数/3時間/ 人)は,2005 ～ 2012年では,5 ～ 7月は0.2(n=24),通年では0.1(n=49)であった。2004年級を主な対象とした2005 ～ 2006年の2年間では,5 ～ 7月は0.3(n=14),通年では0.2(n=23)であった。今回,標本に基づき山口湾を生息地および繁殖地として記載した。Small-scale sillago, Sillago parvisquamis, were collected from Yamaguchi Bay, western Seto Inland Sea, Japan. This species has been evaluated as an endangered species in Japan. Eight specimens (sample no. SPYB1-8) collected in 2005-2008 were 226.5-320.1 mm TL, 197.7-281.0 mm SL and were all adult females. The ages of SPYB1-6, 7, and 8 were 1, 3, and 4 years, respectively, and all individuals were of the 2004 class. Judging from ovarian histological samples, the most developed stage of normal oocytes in SPYB1-7 was the tertiary yolk globule stage or the migratory nucleus stage. All individuals had a lot of post-ovulatory follicles. Therefore, these two evidences indicate spawning. The catch per unit effort (CPUE) (indiv. / 3 hours / person) by fishing in 2005-2012 was 0.2 for the spawning season (n=24) and 0.1 for the whole year (n=49). For the 2004 class, CPUE in 2005-2006 was 0.3 for the spawning season (n=14) and 0.2 for the whole year (n=23). This is the detailed report of the distribution and spawning of Sillago parvisquamis based on specimens from Yamaguchi Bay

Nongyrotropic electron velocity distribution functions near the lunar surface

We have analyzed nongyrotropic electron velocity distribution functions (VDFs) obtained near the lunar surface. Electron VDFs, measured at ∼10–100 km altitude by Kaguya in both the solar wind and the Earth's magnetosphere, exhibit nongyrotropic empty regions associated with the ‘gyroloss’ effect; i.e., electron absorption by the lunar surface combined with electron gyromotion. Particle-trace calculations allow us to derive theoretical forbidden regions in the electron VDFs, thereby taking into account the modifications due to nonuniform magnetic fields caused by diamagnetic-current systems, lunar-surface charging, and electric fields perpendicular to the magnetic field. Comparison between the observed empty regions with the theoretically derived forbidden regions suggests that various components modify the characteristics of the nongyrotropic electron VDFs depending on the ambient-plasma conditions. On the lunar nightside in the magnetotail lobes, negative surface potentials slightly reduce the size of the forbidden regions, but there are no distinct effects of either the diamagnetic current or perpendicular electric fields. On the dayside in the solar wind, the observations suggest the presence of either the diamagnetic-current or solar wind convection electric field effects, or both. In the terrestrial plasma sheet, all three mechanisms can substantially modify the characteristics of the forbidden regions. The observations imply the presence of a local electric field of at least 5 mV/m although the mechanism responsible for production of such a strong electric field is unknown. Analysis of nongyrotropic VDFs associated with the gyroloss effect near solid surfaces can promote a better understanding of the near-surface plasma environment and of plasma–solid-surface interactions

The major histocompatibility complex (Mhc) class IIB region has greater genomic structural flexibility and diversity in the quail than the chicken

BACKGROUND: The quail and chicken major histocompatibility complex (Mhc) genomic regions have a similar overall organization but differ markedly in that the quail has an expanded number of duplicated class I, class IIB, natural killer (NK)-receptor-like, lectin-like and BG genes. Therefore, the elucidation of genetic factors that contribute to the greater Mhc diversity in the quail would help to establish it as a model experimental animal in the investigation of avian Mhc associated diseases. AIMS AND APPROACHES: The main aim here was to characterize the genetic and genomic features of the transcribed major quail MhcIIB (CojaIIB) region that is located between the Tapasin and BRD2 genes, and to compare our findings to the available information for the chicken MhcIIB (BLB). We used four approaches in the study of the quail MhcIIB region, (1) haplotype analyses with polymorphic loci, (2) cloning and sequencing of the RT-PCR CojaIIB products from individuals with different haplotypes, (3) genomic sequencing of the CojaIIB region from the individuals with the different haplotypes, and (4) phylogenetic and duplication analysis to explain the variability of the region between the quail and the chicken. RESULTS: Our results show that the Tapasin-BRD2 segment of the quail Mhc is highly variable in length and in gene transcription intensity and content. Haplotypic sequences were found to vary in length between 4 to 11 kb. Tapasin-BRD2 segments contain one or two major transcribed CojaIIBs that were probably generated by segmental duplications involving c-type lectin-like genes and NK receptor-like genes, gene fusions between two CojaIIBs and transpositions between the major and minor CojaIIB segments. The relative evolutionary speed for generating the MhcIIBs genomic structures from the ancestral BLB2 was estimated to be two times faster in the quail than in the chicken after their separation from a common ancestor. Four types of genomic rearrangement elements (GRE), composed of simple tandem repeats (STR), were identified in the MhcIIB genomic segment located between the Tapasin-BRD2 genes. The GREs have many more STR numbers in the quail than in the chicken that displays strong linkage disequilibrium. CONCLUSION: This study suggests that the Mhc classIIB region has a flexible genomic structure generated by rearrangement elements and rapid SNP accumulation probably as a consequence of the quail adapting to environmental conditions and pathogens during its migratory history after its divergence from the chicken

The alien freshwater shrimp Palaemon sinensis in Japan

近年，日本の淡水域において釣り餌「シラサエビ」として輸入される外来種チュウゴクスジエビ Palaemon sinensis が，日本の淡水域で確認されている。その侵入経路を推測するために各地の釣り具店およびペットショップ（通信販売）におけるエビ類の販売状況，およびチュウゴクスジエビの流通に伴い非意図的に混入する水生動物を調査した。チュウゴクスジエビは，東京都，神奈川県，静岡県，愛知県，大阪府，広島県および福岡県の釣り具店で「シラサエビ」として販売されていたテナガエビ類に含まれていた。非意図的に混入する水生動物として，魚類のモツゴ，ヨコシマドンコ，クロヨシノボリ，ヌマチチブ，チョウセンブナ，甲殻類のエビノコバンおよび昆虫類のミズムシが確認された。本研究により，チュウゴクスジエビが神奈川県，兵庫県，岡山県，島根県，福岡県および佐賀県の流れの緩やかな河川主流路やワンドおよび水路から確認された。The alien freshwater shrimp Palaemon sinensis was recently confirmed in freshwater areas of Japan. To clarify the potential introduction vector of P. sinensis, the occurrence of this shrimp was researched in fishing bait shops in Japan. The shrimp was sold in bait shops in Tokyo, Yokohama, Shizuoka, Nagoya, Osaka, Hiroshima and Fukuoka under the product name “Shirasa ebi”. Five fishes, Pseudorasbora parva, Micropercops swinhonis, Rhinogobius brunneus, Tridentiger brevispinis, and Macropodus ocellatus, one crustacea, Tachea chinensis, and one aquatic insect, Hesperocorixa cf. distanti were unintentionally contained in shrimp samples. P. sinensis was also confirmed in lentic water environments such as main streams and side pool of rivers and agricultural waterways located in Kanagawa, Hyogo, Okayama, Shimane, Fukuoka and Saga prefectures.本研究は科研費（15K06932）の助成を受けた

Detecting the WIMP-wind via spin-dependent interactions

Revealing the nature of dark matter is one of the most interesting tasks in astrophysics. Measuring the distribution of recoil angles is said to be one of the most reliable methods to detect a positive signature of dark matter. We focused on measurements via spin-dependent interactions, and studied the feasibility with carbon tetrafluoride($\rm CF_4$) gas, while taking into account the performance of an existing three-dimensional tracking detector. We consequently found that it is highly possible to detect a positive signature of dark matter via spin-dependent interactions.Comment: 14 pages, 5 figures, submitted for Physics Letters

Direction-sensitive dark matter search results in a surface laboratory

We developed a three-dimensional gaseous tracking device and performed a direction-sensitive dark matter search in a surface laboratory. By using 150 Torr carbon-tetrafluoride (CF_4 gas), we obtained a sky map drawn with the recoil directions of the carbon and fluorine nuclei, and set the first limit on the spin-dependent WIMP (Weakly Interacting Massive Particles)-proton cross section by a direction-sensitive method. Thus, we showed that a WIMP-search experiment with a gaseous tracking device can actually set limits. Furthermore, we demonstrated that this method will potentially play a certain role in revealing the nature of dark matter when a low-background large-volume detector is developed.Comment: 9 figures, accepted for publication in Phys. Lett.