Periodic activity of Comet Bradfield 1987s     

Jun-Ichi Watanabe  Takumi Abe 《Earth, Moon, and Planets》1989,44(2):141-147

A periodic brightness variation of about 6 days was found by applying maximum entropy method to the visual brightness of Comet Bradfield 1987s. This activity was clearly apparent in January of 1988. No other outstanding period was detected. This suggests that the period of the rotation or precession of the nucleus is about 6 days.  相似文献   

Mantle peridotites from the Western Pacific   总被引：1，自引：0，他引：1  

Shoji Arai  Natsue Abe  Satoko Ishimaru 《Gondwana Research》2007,11(1-2):180

We review petrographical and petrological characteristics of mantle peridotite xenoliths from the Western Pacific to construct a petrologic model of the lithospheric mantle beneath the convergent plate boundary. The peridotite varies from highly depleted spinel harzburgite of low-pressure origin at the volcanic front of active arcs (Avacha of Kamchatka arc and Iraya of Luzon–Taiwan arc) to fertile spinel lherzolite of high-pressure origin at the Eurasian continental margin (from Sikhote-Alin through Korea to eastern China) through intermediate lherzolite–harzburgite at backarc side of Japan island arcs. Oxygen fugacity recorded by the peridotite xenoliths decreases from the frontal side of arc to the continental margin. The sub-arc type peridotite is expected to exist beneath the continental margin if accretion of island arc is one of the important processes for continental growth. Its absence suggests replacement by the continental lherzolite at the region of backarc to continental margin. Asthenospheric upwelling beneath the continental region, which has frequently occurred at the Western Pacific, has replaced depleted sub-cratonic peridotite with the fertile spinel lherzolite. Some of these mantle diapirs had opened backarc basins and strongly modified the lithospheric upper mantle by metasomatism and formation of Group II pyroxenites.  相似文献   

Organotin residues and the role of anthropogenic tin sources in the coastal marine environment of Indonesia     

Sudaryanto A  Takahashi S  Iwata H  Tanabe S  Muchtar M  Razak H 《Marine pollution bulletin》2005,50(2):226-235

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Synthetic musks-arising new environmental menace?     

Tanabe S 《Marine pollution bulletin》2005,50(10):1025-1026

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Concentrations of trace elements in marine fish and its risk assessment in Malaysia   总被引：1，自引：0，他引：1  

Agusa T  Kunito T  Yasunaga G  Iwata H  Subramanian A  Ismail A  Tanabe S 《Marine pollution bulletin》2005,51(8-12):896-911

Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sn, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of the Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast might indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than the guideline value by US Environmental Protection Agency (EPA), indicating that consumption of these fish at the present rate may be hazardous to Malaysian people. To our knowledge, this is the first study on multielemental accumulation in marine fish from the Malaysian coast.  相似文献   

Status of butyltin pollution along the coasts of western Japan in 2001, 11 years after partial restrictions on the usage of tributyltin     

Murai R  Takahashi S  Tanabe S  Takeuchi I 《Marine pollution bulletin》2005,51(8-12):940-949

Restrictions on the use of tributyltin (TBT) in aquaculture and on boats in coastal regions, except for ocean-going vessels, have been in place in Japan since 1990 due to the strong toxic effects of TBT on marine organisms. However, TBT pollution along the Japanese coasts has been reported after this legislation was enacted. In order to elucidate the present status of contamination by butyltin (BT) compounds, we measured the levels of BTs [monobutyltin (MBT), dibutyltin (DBT) and TBT] in seawater and Caprella spp. samples obtained from the western part of Seto Inland Sea, Uwa Sea and Uranouchi Bay in western Japan during March to September, 2001. Butyltins were detected in more than 90% of the seawater samples (n = 59), with average concentrations of 8.2 ± 9.2 (SD) ng MBT L⁻¹, 3.3 ± 3.0 ng DBT L⁻¹ and 9.0 ± 7.0 ng TBT L⁻¹. Among 41 stations situated on coastal lines, a sufficient number of Caprella organisms for chemical analysis could be collected from only 16 stations. The butyltin concentrations in seawater and Caprella samples from Uwa Sea and Uranouchi Bay, in which the dominant industry in both waters is aquaculture, showed significantly higher than or no significant differences from those samples from the western part of Seto Inland Sea, a major heavy-industry area in Japan. As the TBT concentration in seawater increased, the number of Caprella organisms collected decreased. The mean TBT concentration among the seawater samples was above the estimated lowest observable effect concentration (LOEC) that reduces the survival rate of Caprella danilevskii. Thus, the present study indicates that TBT is still a potential ecological hazard to the survival of marine invertebrates inhabiting coasts along western Japan, even 11 years after the partial ban on TBT usage was implemented.  相似文献   

Specific accumulation and temporal trends of organochlorine contaminants in Dall's porpoises (Phocoenoides dalli) from Japanese coastal waters     

Kajiwara N  Watanabe M  Tanabe S  Nakamatsu K  Amano M  Miyazaki N 《Marine pollution bulletin》2002,44(10):1089-1099

Organochlorine compounds (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane related compounds, hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), tris(4-chlorophenyl) methane (TCPMe) and tris(4-chlorophenyl) methanol were determined in the blubber of Dall's porpoises (Phocoenoides dalli) collected from Japanese coastal waters in 1998/1999. Among OCs analyzed, PCBs were the predominant contaminants with concentrations ranging from 1.5 to 39 microg/g on a wet weight basis. OCs concentrations were relatively low and less variable in mature females possibly due to the lactational excretion from their bodies, while in males the concentrations were increased with body length. Concentrations and compositions of DDTs and HCHs showed significant differences between the truei-type population off the Pacific coast of northern Japan and dalli-type from the Sea of Japan/Okhotsk, suggesting its usefulness to discriminate different populations. OCs levels detected in truei-type porpoises collected in 1998/1999 were lower than those collected in 1984, except TCPMe. On the other hand, except DDTs, the residue levels of other organochlorines in dalli-type porpoises showed no significant decrease since 1984.  相似文献   

Accumulation features of trace elements in mass-stranded harbor seals (Phoca vitulina) in the North Sea coast in 2002: the body distribution and association with growth and nutrition status     

Agusa T  Yasugi SY  Iida A  Ikemoto T  Anan Y  Kuiken T  Osterhaus AD  Tanabe S  Iwata H 《Marine pollution bulletin》2011,62(5):963-975

Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.  相似文献   

Characteristics of the ratio of dissolved cadmium to phosphate in subtropical coastal waters of Ishigaki Island,Okinawa, Japan     

Kazuo Abe  Kouki Fukuoka  Toru Shimoda 《Journal of Oceanography》2011,67(2):241-248

The ratio of dissolved cadmium (Cd) to phosphate (PO₄) in the subtropical coastal area of Ishigaki Island, Okinawa, Japan, was investigated. Twenty vertical seawater samplings were carried out once a month from May 2008 to January 2010. In order to examine how the Cd/PO₄ ratio in seawater varies with the oceanographic conditions (i.e., the water temperature–salinity characteristics), the water masses at the study sites were classified into two types: group 1 with a water temperature of >25°C and a salinity range of 34.0–34.4, and group 2 with a water temperature of <25°C and a salinity of >34.4. A different phytoplankton assemblage was observed in each water mass defined. Different Cd/PO₄ ratios were obtained for the two water mass types, due to the differences between the types in terms of the environmental conditions such as the water temperature–salinity (T–S) characteristics and phytoplankton assemblages, as well as possible variations in the concentrations of dissolved iron, zinc, manganese, and CO₂ in seawater in each water mass.  相似文献   

Investigation of cutting methods for small samples of Hayabusa and future sample return missions     

Masayuki Uesugi  Ryo Noguchi  Tooru Matsumoto  Junya Matsuno  Takashi Nagano  Akira Tsuchiyama  Shigenori Harada  Kaori Yokoyama  Yoshiaki Yodo  Noboru Takeda  Toru Yada  Shogo Yakame  Yuzuru Karouji  Yukihiro Ishibashi  Masanao Abe  Tatsuaki Okada  Akio Fujimura  Mitsuru Ebihara  Fumio Kitajima  Keisuke Nagao  Tomoki Nakamura  Hiroshi Naraoka  Takaaki Noguchi  Ryuji Okazaki  Hisayoshi Yurimoto 《Meteoritics & planetary science》2014,49(7):1186-1201

We report the investigation of cutting methods for Hayabusa samples. The purpose of our study is to explore the possibility of applying multiple analyses to a single particle effectively. We investigated the cutting performance of a blade dicing saw, laser, focused ion beam (FIB), and physical breaking by microindenter. Cutting performance was examined by estimating the aspect ratio of the cut slit, i.e., depth over width of the slit. We also investigated the possible contamination and sample damage by cutting. The result of the investigation shows that we can cut the samples from <50 μm to 500 μm using those methods with aspect ratios from 10 to 20, although they would introduce some contamination or damage to the samples. Our investigations also provide an important basis for the analysis of samples obtained by future sample return missions.  相似文献