Variation of carbon and nitrogen uptake capacity in a regional upwelling area around Hachijo Island     

Jota Kanda  Toshiro Saino  Akihiko Hattori 《Journal of Oceanography》1985,41(6):373-380

Capacities for inorganic carbon, nitrate and ammonium uptake were measured around Hachijo Island, 300 km south of Tokyo, where local upwelling occurred. The phytoplankton population inside the upwelling area had a high capacity for nitrate uptake and a low capacity for uptake of ammonium. Nutrient concentration and phytoplankton biomass were higher in the upwelling plume than outside. On a chlorophylla basis, phytoplankton populations inside the upwelling area showed a lower capacity for carbon and nitrogen uptake than those outside the upwelling. Low temperature, relatively limited availability of light caused by extensive water mixing within the upwelling plume, and the difference in species composition of phytoplankton must be considered in explaining these lower uptake capacities.  相似文献   

Temporal changes in tree-ring nitrogen of Pinus thunbergii trees exposed to Black-tailed Gull (Larus crassirostris) breeding colonies     

Lopez C.M. Larry  Mizota Chitoshi  Yamanaka Toshiro  Nobori Yoshihiro 《Applied Geochemistry》2010

  相似文献   

Phase F,a new hydrous magnesium silicate synthesized at 1000 °C and 17 GPa: Crystal structure and estimated bulk modulus     

Y. Kudoh  T. Nagase  S. Sasaki  M. Tanaka  M. Kanzaki 《Physics and Chemistry of Minerals》1995,22(5):295-299

The structure of phase F, a non-stoichiometric hydrous silicate synthesized in a uniaxial, split-sphere, multi-anvil apparatus at conditions of 17 GPa and 1000° C, has been solved and refined in space group P6₃cm, using synchrotron X-ray data for a single crystal of a size 18 × 24 × 30 μm. The composition and unit cell for phase F are Mg_3.35Si_5.51H_7.26O₁₈, a=5.073(3) Å, c=14.013(9) Å, 7= 312.3(5) ų. The structure contains layers with many similarities to superhydrous phase B. The layers of oxygen atoms are stacked in the ABCBAC-type double cubic closest packing arrangement. The bulk modulus of phase F was estimated from the structural and compositional relationship to superhydrous phase B and periclase.  相似文献   

Estimating of gas transfer velocity using triple isotopes of dissolved oxygen     

V. V. S. S. Sarma  Osamu Abe  Makio Honda  Toshiro Saino 《Journal of Oceanography》2010,66(4):505-512

The atmosphere-ocean exchange of climatically important gases is determined by the transfer velocity (k) and concentration gradient across the interface. Based on observations in the northwestern subarctic Pacific and Sagami Bay, we report here the results of the first ever application of the natural abundance of triple isotopes of dissolved oxygen (¹⁶O, ¹⁷O and ¹⁸O) for direct estimation of k and propose a new relationship with wind speed. The k values estimated from nighttime variations in oxygen isotopes are found to be higher than the direct estimations at low wind speed (<5 m s⁻¹) and lower at high wind speeds (>13 m s⁻¹) and showed significant spatial variability. The method presented here can be used to derive seasonal and spatial variations in k and the influence of surface conditions on the value, leading to improved estimates of biogenic/anthropogenic gas exchange at the air-sea interface.  相似文献   

Three-dimensional modelling of upper mantle structure under the Pacific Ocean and surrounding area     

Yu Shen Zhang  Toshiro Tanimoto 《Geophysical Journal International》1989,98(2):255-269

  相似文献   

X-ray observation of AGN's from TENMA     

S. Miyoshi  S. Haykawa  H. Kunieda  F. Nagase  Y. Tawara 《Astrophysics and Space Science》1986,119(1):185-190

In order to investigate the structure and mechanism of active galactic nuclei through X-ray observation, detailed energy spectra are examined with the gas scintillation proportional counters on board TENMA. For three selected objects, PKS 2155-304, Centaurus A and IC 4329 A, the observational results in the intensity variation, the spectral shapes and the iron line features are presented.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.  相似文献   

The distribution of X-ray dips with orbital phase in Cygnus X-1     

M. Ba&#;uci&#;ska-Church  M. J. Church  P. A. Charles  F. Nagase  J. LaSala  R. Barnard 《Monthly notices of the Royal Astronomical Society》2000,311(4):861-868

  相似文献   

Validation of a Crop Yield and CO<Subscript>2</Subscript> Fixation Model over Southeast Asia by Carbon Partitioning in Grain Plants     

Daijiro Kaneko  Peng Yang  Toshiro Kumakura 《Journal of the Indian Society of Remote Sensing》2011,39(3):297-306

A photosynthetic-sterility model for grain production monitoring has been developed and validated under the background of climate change and Asian economic growth in developing countries. This paper presents an application of the model to evaluate carbon-fixation rates in yields of paddy rice, winter wheat, and maize in Asia. The validation of the model is based on carbon partitioning in grain plants. The carbon hydrate in grains has the same chemical formula as that of cellulose in grain vegetation. The partitioning of carbon in plants can validate fixation amounts of computed carbon using a satellite-based photosynthesis model. The model estimates the photosynthesis fixation of rice reasonably in Japan and China. Results were validated through examination of carbon in grains, but the model tends to underestimate results for winter wheat and maize. This study also provides daily distributions of the PSN, which is the CO₂ fixation in Asian areas combined with a land-cover distribution classified from MODIS data, NDVI from SPOT VEGETATION, and meteorological re-analysis data by European Centre for Medium-Range Forecasts (ECMWF). The mean CO₂ and carbon fixation rates in paddy areas were 25.92 (t CO₂/ha) and 5.28 (t C/ha) in Japan, respectively. Comparisons between the model’s values and MODIS seasonal PSNs show similar trends. The writers are preparing to compare computed photosynthesis rates with observed AsiaFlux data for the validation of this model at field sites of paddy, grassland and forests in Japan and Asian countries.  相似文献   

Ground motion spatial variability effects on seismic response control of cable-stayed bridges     

Shehata E. Abdel Raheem  Toshiro Hayashikawa  Uwe Dorka 《地震工程与工程振动(英文版)》2011,10(1):37-49

The spatial variability of input ground motion at supporting foundations plays a key role in the structural response of cable-stayed bridges (CSBs); therefore, spatial variation effects should be included in the analysis and design of effective vibration control systems. The control of CSBs represents a challenging and unique problem, with many complexities in modeling, control design and implementation, since the control system should be designed not only to mitigate the dynamic component of the structural response but also to counteract the effects of the pseudo-static component of the response. The spatial variability effects on the feasibility and efficiency of seismic control systems for the vibration control of CSBs are investigated in this paper. The assumption of uniform earthquake motion along the entire bridge may result in quantitative and qualitative differences in seismic response as compared with those produced by uniform motion at all supports. A systematic comparison of passive and active system performance in reducing the structural responses is performed, focusing on the effect of the spatially varying earthquake ground motion on the seismic response of a benchmark CSB model with different control strategies, and demonstrates the importance of accounting for the spatial variability of excitations.  相似文献   

Spectroscopic studies of X-ray binary pulsars     

F. Nagase 《Journal of Astrophysics and Astronomy》2002,23(1-2):59-65

Several new features of X-ray binary pulsars are revealed from recent observations with ASCA, RXTE, BeppoSAX and other X-ray observatories. Among these, I will review in this paper some recent progress in spectroscopic studies of accreting X-ray pulsars in binary systems (XBPs). First, I will discuss soft excess features observed in the energy spectra of XBPs and propose that it is a common feature for various subclasses of XBPs. Next I will present some recent results of high resolution spectroscopy with ASCA and Chandra.  相似文献