Bioenhancement of cadmium transfer along a multi-level food chain     

Seebaugh DR  Goto D  Wallace WG 《Marine environmental research》2005,59(5):77-491

Previous studies have shown that metal partitioned to a subcellular compartment containing trophically available metal (TAM) is readily available to predators and may be enhanced by increased binding of metal to heat-stable proteins (HSP - e.g., metallothioneins). The aim of the current investigation was to determine the influence of TAM on the trophic transfer of Cd along an experimental, three-level food chain: Artemia franciscana (brine shrimp)-->Palaemonetes pugio (grass shrimp)-->Fundulus heteroclitus (mummichog). P. pugio were fed for 7 days on A. franciscana exposed to Cd in solution (including (109)Cd as radiotracer) and subjected to subcellular fractionation or fed to F. heteroclitus. An HSP-driven increase in the percentage of Cd associated with TAM (TAM-Cd%) in A. franciscana exposed to 1 muM Cd resulted in a bioenhancement (i.e., a greater than linear increase with respect to A. franciscana exposure) of Cd trophic transfer to P. pugio. Increased dietary Cd exposure did not affect TAM-Cd% in P. pugio nor trophic transfer to F. heteroclitus.  相似文献   

High heat flow anomalies on an old oceanic plate observed seaward of the Japan Trench     

Makoto Yamano  Masataka Kinoshita  Shusaku Goto 《International Journal of Earth Sciences》2008,97(2):345-352

Thirty-three new measurements on the seaward slope and outer rise of the Japan Trench along a parallel of 38°45′N revealed the existence of high heat flow anomalies on the subducting Pacific plate, where the seafloor age is about 135 m.y.. The most prominent anomaly with the highest value of 114 mW/m² is associated with a small mound on the outer rise, which was reported to be a kind of mud volcano. On the seaward slope of the trench, heat flow is variable: high (70–90 mW/m²) at some locations and normal for the seafloor age (about 50 mW/m²) at others. The spatial variation of heat flow may be related to development of normal faults and horst/graben structures due to bending of the Pacific plate before subduction, with fluid flow along the fault zones enhancing the vertical heat transfer. Possible heat sources of the high heat flow anomalies are intra-plate volcanism in the last several million years like that discovered recently on the Pacific plate east of the Japan Trench.  相似文献   

Deep-sea meiofauna off the Pacific coast of Tohoku and other trench slopes around Japan: a comparative study before and after the 2011 off the Pacific coast of Tohoku Earthquake     

Tomo Kitahashi  Himiko Watanabe  Ken Ikehara  Robert G. Jenkins  Shigeaki Kojima  Motohiro Shimanaga 《Journal of Oceanography》2016,72(1):129-139

  相似文献   

Development and installation of bedload monitoring systems with submerged load cells     

Ken Goto  Takahiro Itoh  Takahiko Nagayama  Rei Utsunomiya  Daizo Tsutsumi  Takahisa Mizuyama 《山地科学学报》2016,13(2):369-376

Bedload governs riverbed channel variations and morphology, it is necessary to determine bedload discharge through an arbitrary cross section in a mountain river. A new system with submerged load cells has been developed to directly measure bedload discharge. The system consists of: (1) an iron box which is 1 m long, 0.5 m wide and 0.1 m in depth, (2) two submerged load cells 0.7 m apart, (3) a pressure sensor and, (4) an electromagnetic velocity meter. This system has been designed to exclude the effect of the hydraulic pressure of water on direct measurements of bedload particle weight. Initial tests in a laboratory were conducted to examine the accuracy of measurements with the system under aerial conditions. The system has been installed in the supercritical flume in Ashi-arai-dani River of the Hodaka Sedimentation Observatory of the Disaster Prevention Research Institute (DPRI) of Kyoto University to obtain bedload discharge under natural conditions. Flume tests were conducted in this channel by artificial supply of uniform sediment particles of several grain sizes. The average velocity of the sediment particles near the bed was estimated using cross-correlation functions for weight waves obtained by the two load cells. Bedload discharge calculations were based on time integration of the product of sediment velocity and sediment weight obtained by the two load cells. This study clarifies the reasons why bedload measurements are difficult, and provides some solutions using the monitoring systems with submerged load cells through the field measurements. Additionally, the applicability of bedload measurement with the submerged load cells is explained based on experimental artificial sediment supply data.  相似文献   

Measured elastic moduli of single-crystal MgO up to 1800 K     

Donald G. Isaak  Orson L. Anderson  Takayasu Goto 《Physics and Chemistry of Minerals》1989,16(7):704-713

Using the rectangular parallelepiped resonance method we measured the temperature dependence of the adiabatic elastic moduli of single-crystal MgO over the temperature range 300–1800 K. The high temperature limit of our measurements extends by 500 K the upper limit over which elasticity data on MgO are now available. Although our measured temperature dependence of C _ij ^s are generally in good agreement with previous measurements over a more narrow range in temperature, we found that C ₄₄ ^s decreases more rapidly with temperature, for T > 1000 K, than previous studies suggest. We also found that each of the slopes (?C ₁₁ ^s /?T)_p, (?K_s/?T)_p, and (C ₄₄ ^s /?T)_p become less negative with increasing temperature for T > 1400 K. From our measurements on elasticity we are able to confirm that the Grüneisen parameter at zero pressure is nearly constant with temperature up to 1800 K, with only a slight decrease above 1000 K. Utilizing our new data we present calculations showing the temperature dependence of thermodynamic parameters important in studies of earth's interior.  相似文献   

Empirical shear wave velocity equations in terms of characteristic soil indexes     

Yutaka Ohta  Noritoshi Goto 《地震工程与结构动力学》1978,6(2):167-187

An investigation to systematize empirical equations for the shear wave velocity of soils was made in terms of four characteristic indexes. The adopted indexes are the N-value of the Standard Penetration Test, depth where the soil is situated, geological epoch and soil type. As some of these indexes are variates belonging to interval scales while others belong to nominal or ordinal scales, the technique known as a multivariate analysis cannot be employed. A new approach to the theory of quantification, after C. Hayashi, was introduced and developed for solving this difficulty. Fifteen sets of empirical equations to estimate low strain shear wave velocity theoretically may be obtained by combining the above four indexes. All of these sets were derived by use of about 300 data, and their accuracies were evaluated by means of correlation coefficients between the measured and estimated shear wave velocities. The best equation was found to be the one which included all the indexes, and its correlation coefficient was 0.86. The empirical equation relating the standard penetration N-value to the shear wave velocity provided a correlation of only 0.72, and is one of the lowest ranking among the 15 sets of equations.  相似文献   

Absorption spectra of Cr3+ in Al2O3 under shock compression     

Tsuneaki Goto  Thomas J. Ahrens  George R. Rossman 《Physics and Chemistry of Minerals》1979,4(3):253-263

Unpolarized absorption spectra of single crystals of Cr³⁺ doped Al₂O₃ (synthetic ruby) have measured using a new, time-resolving, dispersive, streak photographic system over the range ～350 to ～700 nm during a series of shock loading experiments. The crystal field absorptions assigned to the transition ⁴ A _2g→⁴ T _2g were observed to shift in a series of experiments from 555±1 nm at atmospheric pressure to 503±5 nm at 46 GPa. In a single experiment at 32 GPa the ⁴ A _2g→⁴ T _1g transition was observed to shift from 405±1 to 386±5 nm. The present data extrapolate downwards in compression toward the 10 GPa data of Stephens and Drickamer (1961) although both crystal field absorption energies increase considerably less with compression than predicted by the simple ionic point charge model. The single datum observed for the Racah parameter B, 588±38 cm^?1 at 32 GPa, is consistant with previous results to 10 GPa and the trend of decreasing B, with compression expected from the divergence of the data from the point charge model due to increasing covalancy.  相似文献   

Temporal changes in thermal waters related to volcanic activity of Tokachidake Volcano,Japan: implications for forecasting future eruptions     

Ryo Takahashi  Tomo Shibata  Yasuji Murayama  Tagiru Ogino  Noritoshi Okazaki 《Bulletin of Volcanology》2015,77(1):1-12

  相似文献   

Abundance diagnosis of E+A (post-starburst) galaxies   总被引：1，自引：0，他引：1  

Tomotsugu Goto 《Monthly notices of the Royal Astronomical Society》2007,377(3):1222-1228

  相似文献   

Relevance of intracellular partitioning of metals in prey to differential metal bioaccumulation among populations of mummichogs (Fundulus heteroclitus)     

Daisuke Goto  William G. Wallace   《Marine environmental research》2009,68(5):257-267

Intracellular partitioning of trace metals is critical to metal tolerance in aquatic organisms and may also influence metal trophic transfer in ecosystems. In this study, we tested the relevance of metal (Cd, Cu, Pb, and Zn) intracellular partitioning in prey as an indicator of metal trophic availability to benthic forage fish, mummichogs (Fundulus heteroclitus), in chronically metal-polluted salt marshes in New York, USA. Two common prey of mummichogs in the study area, Palaemonetes pugio and Nereis acuminata, generally stored increasingly higher proportions of non-essential metals (particularly Pb) in insoluble (less trophically available) cellular components, as the whole body burdens increased. In contrast, intracellular partitioning of essential metals (Cu and Zn) in invertebrate prey varied relatively little among sites. Differential Cd and Pb intracellular partitioning patterns within P. pugio among sites were significantly associated with Cd and Pb whole body burdens in mummichogs, respectively (i.e., prey-driven bioreduction of metals), while bioaccumulation of Cu and Zn in mummichogs was similar among populations. The findings in this study suggest that metal intracellular partitioning within prey may be partially responsible for metal trophic availability to a predator in metal-polluted habitats, while there was also evidence that some predator-dependent processes may offset differential trophic availabilities from prey.  相似文献