著者

Kentaro Nakamura Shinsuke Kawagucci Kazuya Kitada Hidenori Kumagai Ken Takai Kyoko Okino

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

vol.49, no.6, pp.579-596, 2015-11-26 (Released:2015-12-05)

参考文献数

40

被引用文献数

37 61

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Polymetallic sulfides deposited in seafloor hydrothermal vents have recently attracted attention as potential deep-sea mineral resources for base, rare, and precious metals such as Cu, Zn, Pb, In, Ga, Ge, Au, and Ag. For future exploitation of this type of deep-sea mineral resources, development of effective methods for exploring seafloor hydrothermal activity is a key to provide the most promising list of fields. However, conventional exploration methods are likely laborious and time-consuming, and a more efficient methods for exploration of seafloor hydrothermal vents are to be further developed. In the last decade, water column observation using multibeam echo souder (MBES) systems have become successfully applied to exploration of seafloor hydrothermal vents. In 2013 and 2014, we conducted extensive water column surveys using MBES systems in the mid-Okinawa Trough. During the surveys, we detected 10 hydrothermal vent sites, including previously known sites, belonging to four relatively large hydrothermal vent fields, located at the Izena Hole, Iheya North Knoll, Iheya Small Ridge, and a seamount 15 km northwest of the Izena Hole. All of the hydrothermal vent sites are in groups of 2–3 vent sites belonging to a hydrothermal field. Morphological features of the acoustic water column anomalies (rising vertically up to ~1000 m from the seafloor without a significant change of width) implied that the acoustic water column anomalies were not caused directly by hydrothermal vent fluid flows. The depth of the top of the acoustic water column anomalies (~500 m) corresponded rather well to the depth of the CO2 phase transition from liquid/clathrate-hydrate to vapor. This suggests that the acoustic water column anomalies are attributed to water mass including dense liquid CO2 droplets with clathrate-hydrate crusts, which are originally derived from the seafloor hydrothermal fluid discharges.

著者

Marie Tabaru Ryusuke Fujino Kentaro Nakamura

出版者

ACOUSTICAL SOCIETY OF JAPAN

雑誌

Acoustical Science and Technology (ISSN:13463969)

巻号頁・発行日

vol.36, no.2, pp.167-170, 2015-02-01 (Released:2015-03-01)

参考文献数

9

被引用文献数

3

著者

Shuri Kato Asako Matsumoto Kensuke Yoshimura Toshio Katsuki Kojiro Iwamoto Yoshiaki Tsuda Shogo Ishio Kentaro Nakamura Kazuo Moriwaki Toshihiko Shiroishi Takashi Gojobori Hiroshi Yoshimaru

出版者

日本育種学会

雑誌

Breeding Science (ISSN:13447610)

巻号頁・発行日

vol.62, no.3, pp.248-255, 2012 (Released:2012-11-01)

参考文献数

36

被引用文献数

4 18

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Numerous cultivars of Japanese flowering cherry (Prunus subgenus Cerasus) are recognized, but in many cases they are difficult to distinguish morphologically. Therefore, we evaluated the clonal status of 215 designated cultivars using 17 SSR markers. More than half the cultivars were morphologically distinct and had unique genotypes. However, 22 cultivars were found to consist of multiple clones, which probably originate from the chance seedlings, suggesting that their unique characteristics have not been maintained through propagation by grafting alone. We also identified 23 groups consisting of two or more cultivars with identical genotypes. Most members of these groups were putatively synonymously related and morphologically identical. However, some of them were probably derived from bud sport mutants and had distinct morphologies. SSR marker analysis provided useful insights into the clonal status of the examined Japanese flowering cherry cultivars and proved to be a useful tool for cultivar characterization.

著者

Neisei Hayashi Yosuke Mizuno Heeyoung Lee Kentaro Nakamura Sze Yun Set Shinji Yamashita

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

vol.17, no.12, pp.20200139, 2020-06-25 (Released:2020-06-25)

参考文献数

39

被引用文献数

2 5

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We present a method for generating cascaded forward Brillouin scattering (CFBS) on the basis of a counter-propagated pump-probe technique with backward stimulated Brillouin scattering used as its seed. The CFBS, induced by forward stimulated Brillouin scattering (FSBS), is generated via the energy transfer from the probe light to other acoustic resonance frequencies. The CFBS spectrum generated in a 390-m-long highly nonlinear fiber exhibits a high signal-to-noise ratio (SNR), and the center frequencies of its acoustic resonance peaks agree with theoretical values. In addition, the SNR dependence on pump/probe powers and the CFBS frequency shift dependence on temperature are investigated.

著者

Koji Numaguchi Shogo Ishio Yuto Kitamura Kentaro Nakamura Ryo Ishikawa Takashige Ishii

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-013, (Released:2019-01-18)

被引用文献数

7

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Japanese apricot (Prunus mume Sieb. et Zucc.) is one of the major fruit tree crops in Japan. However, a paucity of molecular tools has limited studies on the species’ genetic diversity and clone identification. Therefore, we newly designed 201 microsatellite markers using the P. mume reference genome and selected 20 highly polymorphic markers. The markers showed higher polymorphism detectability than those previously developed using peach and apricot genomes. They were used successfully for fingerprinting most of the Prunus cultivars examined (124 P. mume accessions and one accession each of P. armeniaca, P. salicina, P. persica, and P. dulcis), and the resulting genotype data were used to examine the genetic differentiation of six Japanese apricot cultivar groups, including those producing normal fruit, small-fruit, and ornamental flowers, as well as Taiwanese cultivars, putative hybrids of P. armeniaca and P. mume, and putative hybrids of P. salicina and P. mume. Phylogenetic cluster analysis showed three clades with high support values; one clade comprised the putative P. armeniaca × P. mume hybrids, and the two others included Taiwanese and ornamental cultivars. The rest of the accessions were grouped into two wide clusters, but not clearly divided into the respective cultivar groups. These complex relationships were supported by the principal coordinate and STRUCTURE analyses. Since Japanese apricot is thought to have originated in China, many factors such as human preference, geographical separation, introgression, and local breeding, may have been involved to form the present complex genetic structure in Japanese apricot.