Imposex in Japanese gastropods (neogastropoda and mesogastropoda): Effects of tributyltin and triphenyltin from antifouling paints     

T. Horiguchi  H. Shiraishi  M. Shimizu  S. Yamazaki  M. Morita 《Marine pollution bulletin》1995,31(4-12):402-405

In Japan, marine pollution by organotin compounds is serious and imposex is known to occur in marine gastropods. However, a detailed survey on imposex had not previously been conducted. The first country-wide survey and laboratory experiments on imposex in Japanese gastropods has now been carried out, and the results are reported herein.  相似文献   

Real-time geophysical measurements on the deep seafloor usingsubmarine cable in the southern Kurile subduction zone     

Hirata  K. Aoyagi  M. Mikada  H. Kawaguchi  K. Kaiho  Y. Iwase  R. Morita  S. Fujisawa  I. Sugioka  H. Mitsuzawa  K. Suyehiro  K. Kinoshita  H. Fujiwara  N. 《Oceanic Engineering, IEEE Journal of》2002,27(2):170-181

A permanent real-time geophysical observatory using a submarine cable was developed and deployed to monitor seismicity, tsunamis, and other geophysical phenomena in the southern Kurile subduction zone. The geophysical observatory comprises six bottom sensor units, two branching units, a main electro-optical cable with a length of 240 km and two land stations. The bottom sensor units are: 1) three ocean bottom broadband seismometers with hydrophone; 2) two pressure gauges (PGs); 3) a cable end station with environmental measurement sensors. Real-time data from all the undersea sensors are transmitted through the main electro-optical cable to the land station. The geophysical observatory was installed on the continental slope of the southern Kurile trench, southeast Hokkaido, Japan in July 1999. Examples of observed data are presented. Sensor noises and resolution are mentioned for the ocean bottom broadband seismometers and the PGs, respectively. An adaptable observation system including very broadband seismometers is scheduled to be connected to the branching unit in late 2001. The real-time geophysical observatory is expected to greatly advance the understanding of geophysical phenomena in the southern Kurile subduction zone  相似文献   

Characteristics of Porphyry Cu Mineralization at Waisoi (Namosi District), Viti Levu, Fiji     

Akira Imai    Yukiko Ohbuchi    Takayuki Tanaka    Seiya Morita  Kentaro Yasunaga 《Resource Geology》2007,57(4):374-385

The porphyry Cu deposits at Waisoi in Namosi district, Viti Levu are separated into two deposits: the Waisoi East deposit and the Waisoi West deposit. In the Waisoi East deposit, quartz porphyry is exposed and in the Waisoi West deposit, diorite porphyry is sporadically exposed in addition to a small body of quartz porphyry. The mineralization in the Waisoi East deposit is characterized by the bornite–chalcopyrite–pyrite assemblage associated with traces of molybdenite and native gold. Polyphase fluid inclusions in stockwork quartz veinlets show homogenization temperatures ranging from 210 to >500°C. The high‐grade Cu mineralization in the Waisoi West deposit is characterized by the bornite–chalcopyrite–pyrite assemblage accompanied with sheeted and stockwork quartz veinlets. Polyphase fluid inclusions occasionally containing hematite flakes in quartz veinlets in the center of the Waisoi West deposit homogenize at temperatures ranging from 450°C to >500°C. However, fluid inclusions in stockwork quartz veinlets in the periphery, homogenize at lower temperatures around 210°C. Both in the Waisoi East and Waisoi West deposits, primary bornite–chalcopyrite–pyrite assemblage in the high Cu‐grade zone was deposited at the upper stability limit of chalcopyrite with respect to sulfur fugacity. Thus, the principal Cu mineralization at the Waisoi deposits occurred at a relatively high sulfur fugacity, that is, in a high‐sulfidation environment.  相似文献   

Low-temperature heat capacities,entropies and high-pressure phase relations of MgSiO<Subscript>3</Subscript> ilmenite and perovskite     

M. Akaogi  H. Kojitani  T. Morita  H. Kawaji  T. Atake 《Physics and Chemistry of Minerals》2008,35(5):287-297

Low-temperature isobaric heat capacities (C _p ) of MgSiO₃ ilmenite and perovskite were measured in the temperature range of 1.9–302.4 K with a thermal relaxation method using the Physical Properties Measurement System. The measured C _p of perovskite was higher than that of ilmenite in the whole temperature range studied. From the measured C _p , standard entropies at 298.15 K of MgSiO₃ ilmenite and perovskite were determined to be 53.7 ± 0.4 and 57.9 ± 0.3 J/mol K, respectively. The positive entropy change (4.2 ± 0.5 J/mol K) of the ilmenite–perovskite transition in MgSiO₃ is compatible with structural change across the transition in which coordination of Mg atoms is changed from sixfold to eightfold. Calculation of the ilmenite–perovskite transition boundary using the measured entropies and published enthalpy data gives an equilibrium transition boundary at about 20–23 GPa at 1,000–2,000 K with a Clapeyron slope of −2.4 ± 0.4 MPa/K at 1,600 K. The calculated boundary is almost consistent within the errors with those determined by high-pressure high-temperature in situ X-ray diffraction experiments.  相似文献   

Diffuse carbon dioxide emissions from hidden subsurface structures at Asama volcano,Japan     

Masaaki Morita  Toshiya Mori  Ryunosuke Kazahaya  Hiroshi Tsuji 《Bulletin of Volcanology》2016,78(3):17

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Neoproterozoic Attunga Eclogite in Eastern Australia Margin   总被引：1，自引：0，他引：1  

T. Watanabe  C.M. Fanning  E. Leitch  T. Morita 《Gondwana Research》1999,2(4):616

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Continuing observation of disturbed reproductive cycle and ovarian spermatogenesis in the giant abalone, Haliotis madaka from an organotin-contaminated site of Japan     

Toshihiro Horiguchi  Mitsuhiro Kojima  Naoyuki Takiguchi  Miyuki Kaya  Hiroaki Shiraishi  Masatoshi Morita 《Marine pollution bulletin》2005,51(8-12):817

Histological examination of gonads as well as chemical analysis of organotin compounds in tissues of the giant abalone, Haliotis madaka, was conducted to evaluate continuing endocrine disruption in abalone populations in Japan. Abalone specimens were collected from two different areas, Tsushima as a reference site and Jogashima as a site representative of declining abalone populations where serious organotin contamination had been observed, each month from January 1998 to March 1999. Scores were given to the development stages of reproductive cells in the ovary and testis. The degree of sexual maturation was evaluated by calculating the mean value of a histogram of these scores for the reproductive cells of each abalone. The temporal variations in degree of sexual maturation showed that female and male abalone from Tsushima matured synchronously, while those from Jogashima did not, which were similar to results of the previous study during September 1995–November 1996. Approximately 19% of the female abalone from Jogashima were masculinized with an ovo-testis, which was also similar to the result of the previous study. The masculinization of female abalone is reported to be induced by tributyltin (TBT) and triphenyltin (TPhT) from antifouling paints. Concentrations of the sum of butyltins (TBT, dibutyltin (DBT) and monobutyltin (MBT): ΣBTs) and the sum of phenyltins (TPhT, diphenyltin (DPhT) and monophenyltin (MPhT): ΣPhTs) in the muscle of abalone from Jogashima (n = 73) of 7.8 ± 9.0 ng/g wet wt. and 4.5 ± 6.8 ng/g wet wt., respectively, were significantly higher than those from Tsushima (n = 87) of 4.7 ± 4.9 ng/g wet wt. and 0.8 ± 1.7 ng/g wet wt., respectively (p < 0.05 for ΣBTs; p < 0.001 for ΣPhTs), although concentrations of TBT and TPhT in the muscle of abalone from Jogashima (n = 73) of 2.2 ± 2.5 ng/g wet wt. and 5.8 ± 5.1 ng/g wet wt., respectively, were insignificantly and significantly higher than those from Tsushima (n = 87) of 0.4 ± 0.6 ng/g wet wt. and 0.5 ± 0.9 ng/g wet wt., respectively, (p > 0.05 for TBT; p < 0.001 for TPhT). Thus, endocrine disruption as well as contamination by organotins in the giant abalone from Jogashima is still persisting.  相似文献   

Chemical evidence for the origin of the cold water belt along the northeastern coast of Hokkaido     

Kenshi Kuma  Ryohei Sasayama  Nanako Hioki  Yuichiroh Morita  Yutaka Isoda  Tohru Hirawake  Keiri Imai  Takafumi Aramaki  Tomohiro Nakamura  Jun Nishioka  Naoto Ebuchi 《Journal of Oceanography》2014,70(4):377-387

In the southwestern Okhotsk Sea, the cold water belt (CWB) is frequently observed on satellite images offshore of the Soya Warm Current flowing along the northeastern coast of Hokkaido, Japan, during summertime. It has been speculated that the CWB is upwelling cold water that originates from either subsurface water of the Japan Sea off Sakhalin or bottom water of the Okhotsk Sea. Hydrographic and chemical observations (nutrients, humic-type fluorescence intensity, and iron) were conducted in the northern Japan Sea and southwestern Okhotsk Sea in early summer 2011 to clarify the origin of the CWB. Temperature–salinity relationships, vertical distributions of chemical components, profiles of chemical components against density, and the (NO₃ + NO₂)/PO₄ relationship confirm that water in the CWB predominantly originates from Japan Sea subsurface water.  相似文献   

Highly radiative shock experiments driven by GEKKO XII     

A. Dizi��re  C. Michaut  M. Koenig  C. D. Gregory  A. Ravasio  Y. Sakawa  Y. Kuramitsu  T. Morita  T. Ide  H. Tanji  H. Takabe  P. Barroso  J.-M. Boudenne 《Astrophysics and Space Science》2011,336(1):213-218

In this paper, recent results obtained on highly radiative shocks generated in a xenon filled gas cell using the GEKKO XII laser facility are presented. Data show extremely high shock velocity (??150 km/s) never achieved before in gas. Preliminary analyses based on theoretical dimensionless numbers and numerical simulations suggest that these radiative shocks reach a new radiative regime where the radiative pressure plays a role in the dynamics and structure of the shock. A major effect observed is a strong anisotropic emission in the downstream gas. This unexpected feature is discussed and compared to available 2D radiation hydrodynamic simulations.  相似文献