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Reiji Kobayashi 《Geophysical Journal International》1998,135(3):893-897
We calculate surface waves propagating in a laterally heterogeneous structure beneath the Kuril trench, where significant Love-wave polarization anomalies, called quasi-Love waves, are generated. Since 3-D wave propagation in the two-dimensionally heterogeneous structure can be assumed, we apply the 2.5-D finite difference method to the surface-wave calculations. The calculations show that a velocity contrast of 7 per cent at depths of less than 210 km beneath the Kuril trench cannot generate quasi-Love waves, and that an unlikely contrast of 20 per cent is required to generate clear quasi-Love waves. The possible cause of the quasi-Love waves inferred from previous studies on coupled free oscillations is a lateral variation in azimuthal anisotropy. The lateral variation in azimuthal anisotropy beneath the Kuril trench suggests a change in the mantle flow induced by the subducting slab. 相似文献
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Kunito T Nakamura S Ikemoto T Anan Y Kubota R Tanabe S Rosas FC Fillmann G Readman JW 《Marine pollution bulletin》2004,49(7-8):574-587
Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n = 20), Franciscana dolphin (Pontoporia blainvillei; n = 23), Atlantic spotted dolphin (Stenella frontalis; n = 2), common dolphin (Delphinus capensis; n = 1) and striped dolphin (Stenella coeruleoalba; n = 1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 microg/g dry wt.) and Zn (range, 242-369 microg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 microg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg+0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag2Se in the liver of Franciscana dolphin. 相似文献
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There is not much information in the literature about the energy partitioning and micrometeorological features of sunn hemp. Therefore, in this study, the variations in the energy-balance components and plant characteristics such as aerodynamic and surface conductance, crop coefficient, albedo, short- and long wave down- and upward radiation have been measured and estimated for the time period from August to October 2004 over an irrigated sand field at the Arid Land Research Center in Tottori, Japan. The Bowen ratio energy-balance method was used to calculate the partitioning of heat fluxes of sunn hemp. The Bowen ratio values at the first growing stages in August were found to be higher than the Bowen ratio values at the latest growing stages in September and October because of the heavy rain and high soil-water content. The daytime averaged Bowen ratio was 0.19. During the measurement period, the daytime average net radiation, and soil, latent and sensible heat fluxes were approximately 231, 28, 164, and 39 W m–2, respectively. The net radiation and soil heat flux showed decreasing trends from the beginning to the end of the experiment period due to the atmospheric and crop growth conditions. The daytime averages of aerodynamic and surface conductance for sunn hemp were around 31 and 17 mm s–1, respectively. Also, the daytime average albedo of sunn hemp was around 19%. Finally, the high precipitation amount due to typhoons, high soil-water content, low available energy and low vapor-pressure deficit lead to decreasing trend of the energy fluxes during the generative phase of sunn hemp. 相似文献
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Estimation of surface soil water content from surface temperatures in dust source regions of Mongolia and China 总被引：2，自引：2，他引：0
Surface conditions, such as surface roughness and soil moisture, control wind erosion and dust emission in northeast Asia.
Data on spatial and temporal changes of surface soil water content are needed for dust-modeling systems used to predict dust
events with the aim of preventing damage from them. A modified temperature-vegetation dryness index (MTVDI) was tested to
see if it could reproduce surface soil water contents measured during the dust event season in Bayan Unjuul, Mongolia, and
Shenmu, China. MTVDI was calculated from land surface temperature and aerodynamic minimum and maximum surface temperatures
estimated from meteorological data. The standard deviation of the error of estimations of soil water content from MTVDI was
±1.5% in Bayan Unjuul when soil water content was lower than 4%. This compares favorably with the observational error of ±1%
of the soil moisture sensors used. 相似文献
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Levent Şaylan Reiji Kimura Erdenebayar Munkhtsetseg Makio Kamichika 《Theoretical and Applied Climatology》2011,105(1-2):277-286
In this study, variations in carbon dioxide (CO2) fluxes resulting from gross primary production (GPP), net ecosystem exchange (NEE), and respiration (R e) of soybean (Glycine max L.) were investigated by the Eddy Covariance method during the growing period from June to November 2005 on an irrigated sand field at the Arid Land Research Center, Tottori University in Tottori, Japan. Although climatic conditions were humid and temperate, the soybeans required frequent irrigation because of the low water holding capacity of the sandy soil at the field site. Finally, it has been found that the accumulated NEE, GPP, and R e fluxes of soybean over 126 days amount to ?93, 319, and 226 gC m?2, respectively. Furthermore, the average ratio of GPP to R e was 1.4 and the average ratio of NEE to GPP was about ?0.29 for the growth period of soybean. Daily maximum NEE of ?3.8 gC m?2 occurred when LAI was 1.1. 相似文献
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The John Martin Reservoir tracksites from the Dakota Group of Bent County, in southeastern Colorado form part of the mid Cretaceous Dinosaur Freeway characterized by abundant ornithopod footprints (Caririchnium). Over 350 tracks (331 Caririchnium, 1 Magnoavipes, 22 crocodiles, and a few pterosaurs) were discovered at 10 new tracksites. All tracks were found as natural casts, including Caririchnium trackways that were still in-situ, parallel and regularly spaced, suggesting gregarious behavior. Most crocodile tracks are swimming tracks that consist of three or four scratch marks also with parallel orientations in many cases. A few pterosaur tracks consist of pes footprints and scratch marks suggesting swimming or floating activity in shallow water. This is the first pterosaur evidence from the Dakota Group. The Caririchnium size structure from John Martin Reservoir is consistent with the size structure tendency of the whole Dinosaur Freeway, which shows larger track size in the north. This tendency could be interpreted as evidence for more than one ornithopod species spread out across the Dinosaur Freeway. The alternative, that there was one ornithopod species that migrated north and south seasonally is less likely. The John Martin paleoecosystem is interpreted from the track evidence as a well-vegetated coastal plain environment with many ornithopods and a few theropods on land, crocodiles in the water, and pterosaurs in the skies and on the water. 相似文献
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Kubota R Kunito T Fujihara J Tanabe S Yang J Miyazaki N 《Marine pollution bulletin》2005,51(8-12):845-849
Concentrations of total arsenic and individual arsenic compounds were determined in liver, muscle, kidney and blubber of mother and fetus of Dall’s porpoises collected from off Sanriku, Japan, in the year 2000 to characterize the placental transfer of arsenic to fetus in cetaceans. Arsenic was detected in all the tissues of Dall’s porpoises. Total arsenic concentrations in liver, kidney, muscle and blubber were 0.76, 0.69, 0.35 and 0.55 μg/g wet wt, respectively, for mother and 0.28, 0.23, 0.26 and 0.07 μg/g wet wt, respectively, for fetus. In all the tissues, concentrations of total arsenic in mother Dall’s porpoise were higher than in fetus. Arsenic speciation revealed that arsenobetaine was the major arsenic compound in liver, kidney and muscle of both mother and fetus. The percentage of arsenobetaine to total arsenic ranged from 76.0 to 91.0% in the tissues. Dimethylarsinic acid, arsenocholine, methylarsonic acid and an unidentified arsenic compound were also detected in tissues of both mother and fetus as minor constituents, whereas tetramethylarsonium ion was not detected in tissues of the fetus. These results suggest that arsenobetaine, dimethylarsinic acid, arsenocholine and methylarsonic acid are transferable from mother to fetus in Dall’s porpoises. To our knowledge, this is the first report on placental transfer of arsenic compounds to fetus in marine mammals. 相似文献
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Yoshihiro Yokoyama Hiroshi Tsukamoto Tohru Suzuki Shohshi Mizuta Reiji Yoshinaka 《中国海洋大学学报(英文版)》2005,4(3):214-218
In this study, genes of two distinct tissue inhibitors of metalloproteinases-2 (TIMP-2) from Japanese puffer fish Fugu rubripes, Fugu TIMP-2a and TIMP-2b, were cloned. The open reading frames of Fugu TIMP-2a and TIMP-2b cDNAs are composed of 660 and 657 nucleotides and 220 and 219 amino acids, respectively. Both Fugu TIMP-2s contain 12 cysteine residues, which might form six disulfide bonds as in other animals’ TIMP-2s. Reverse-transcribed
polymerase chain reaction analysis showed the mRNAs of Fugu TIMP-2a and TIMP-2b to be expressed in some tissues examined with different expression patterns. These findings suggest that
the two distinct Fugu TIMP-2s might perform different functions in Fugu tissues. 相似文献