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111.
Karyotypes of the brackish-water polychaeteNeanthes japonica (Izuka) collected from five rivers in Japan from 1984 to 1988 were examined with air-drying and flame-drying methods using materials consisting of regenerating tails, clumps of spermatogonia and youngN. japonica specimens (embryos, larvae or juveniles). A diploid number of 28 was determined in well-spread metaphase chromosomes of mitotic cells. The presence of an XX-XY (male heterogametic) sex chromosome system was established for the first time in polychaetes. The Y chromosome was larger than the X chromosome. Slight differences in karyotype were found between two forms (the small- and large-egg forms), which are very similar in adult morphology but can be distinguished by reproductive and developmental characteristics. 相似文献
112.
Naoko Seino Hidetaka Sasaki Junji Sato Masaru Chiba 《Atmospheric environment (Oxford, England : 1994)》2004,38(40):7073
After severe eruptions of the volcano at Miyake Island in August 2000, a large amount of volcanic gas was released into the atmosphere. To simulate flows and dispersion of sulfur dioxide (SO2) over Miyake Island, a set of numerical models was developed. The multi-nesting method was adopted to reflect a realistic meteorological field and to sufficiently resolve the flow over the island with a diameter of 8 km. The outermost model was the Regional Spectral Model (RSM) of the Japan Meteorological Agency (JMA) with a horizontal grid size of 10 km. Finer atmospheric structure was simulated with the nonhydrostatic model jointly developed by the Meteorological Research Institute and the Numerical Prediction Division of JMA (MRI/NPD-NHM) with grid intervals of 2 km, 400 m and 100 m. Realistic topography of the island was represented in the innermost model. The Lagrangian particle method was applied to the dispersion model, which is driven by the meteorological field of the 100 m grid MRI/NPD-NHM. The random walk procedure was used to represent the turbulent diffusion. The model was verified in four cases. Simulated SO2 concentrations agreed well with observed concentrations at a monitoring station including temporal variation. Under a large synoptic change, however, accurate prediction became difficult. Further numerical experiments have been done to investigate characteristics of the flow and the distribution of SO2. Steady inflows, classified according to the surface wind speed and direction, were assumed. Simulated SO2 distribution on the ground apparently depends on the surface wind. Under relatively weak inflow, there is a large diurnal change in SO2 distribution, affected by the thermally induced flow. SO2 gas is widely spread downstream in the nighttime but hardly reaches the coastal area in the daytime. On the other hand, SO2 gas steadily reached the downstream coast with little diurnal variation under the stronger inflow. Ground temperature, as well as the static stability of the inflow, also influences downstream wind, turbulent diffusivity and SO2 distribution. 相似文献
113.
Sato E Shibata K Wu YX Uezato T Kobayashi K Miura N 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(1):39-43
Skin darkened tadpoles sometimes appear spontaneously. Darkened was artificially induced in Xenopus larvae by yohimbine or chlorpromazine. These phenomena look like that are seen at pinealectomized or hypothalamus separated Xenopus larva. In this experiment, such a morphological color changed Xenopus larva is suggested by cause of inhibition of alpha2-adrenargic receptor or dopamine receptor from gastrula stages. 相似文献
114.
The acute effects of combined exposure to temperature increase and chlorination on a neritic marine copepod, Acartia omorii Bradford (collected offshore of Onjuku, Japan in 1982), were investigated in the laboratory. Continuous flow exposure and batch exposure modes were compared. Based on the results of continuous flow experiments, the 24-h median lethal concentration (24-h LC50, in mg l-1) of total residual chlorine was estimated using the multiple regression equation below, with a multiple correlation coefficient of 0.955: 24-h LC50=2.988-0.034 dT-1.611 log10
t where dT is temperature rise (°C) and t is exposure duration (min). In batch experiments, the predictive power of the multiple regression equation was reduced, probably due to variations in chlorine concentration during exposure duration. 相似文献
115.
Kimio Sato 《Journal of Loss Prevention in the Process Industries》1989,2(4):209-214
Steam curtain equipment is used to prevent leaking flammable gases from reaching ignition sources, such as furnaces. However, steam curtains are sometimes designed badly and are ineffective for preventing the leaking gas from spreading in the windward direction. The leaked gas may pass on either side of the stream curtain, it may pass between the nozzles, or it may pass on the upper side of the stream curtain. At present, data to design the best stream curtains are quite rare. It is necessary to obtain fundamental data on the entrainment of air by steam jet and on the inclination of the steam curtain caused by the strong wind. Therefore, a series of experiments to investigate the entrained air and the inclination of the steam curtain were performed, in addition to further theoretical considerations. Thus, fundamental data useful for the design of the steam curtain equipment have been obtained. 相似文献
116.
Diffusion mechanism of chloride ions in sodium montmorillonite 总被引:4,自引:0,他引:4
For safety assessment of geological disposal of HLW, it is necessary to understand the diffusion mechanism of radionuclides in compacted bentonite. In this study, the diffusion behavior of chloride ions in compacted montmorillonite was studied from the viewpoints of the activation energy for apparent diffusion and the basal spacing of the compacted montmorillonite. A unique change in the activation energy as a function of the dry density of the montmorillonite was found. The activation energy decreased from 17.4 to 13.5 kJ mol-1 as the dry density increased from 0.7 to 1.0 Mg m-3 and increased to 25.1 kJ mol-1 at dry densities above 1.0 Mg m-3. The basal spacing of 1.88 nm, corresponding to the three-water layer hydrate state, was not observed by X-ray diffraction (XRD) until the dry density increased to 1.0 Mg m-3, where the minimum activation energy was obtained. On the other hand, a basal spacing of 1.56 nm, corresponding to the two-water layer hydrate state, was observed at the dry densities of 1.4 Mg m-3 and above, where the activation energies were more than 22 kJ mol-1. These experimental results suggest that there are at least two additional diffusion processes that can raise or reduce the activation energy and are affected by water in the region adjacent to the montmorillonite surfaces. If the "Grahame model" can be introduced to describe the electrical double layer, surface diffusion will be considered the possible predominant diffusion process, even for anions like chloride ions. 相似文献
117.
The sorption and desorption behavior of radium on bentonite and purified smectite was investigated as a function of pH, ionic strength and liquid to solid ratio by batch experiments. The distribution coefficients (Kd) were in the range of 10(2) to > 10(4) ml g-1 and depended on ionic strength and pH. Most of sorbed Ra was desorbed by 1 M KCl. The results for purified smectite indicated that Ra sorption is dominated by ion exchange at layer sites of smectite, and surface complexation at edge sites may increase Ra sorption at higher pH region. Reaction parameters between Ra and smectite were determined based on an interaction model between smectite and groundwater. The reaction parameters were then used to explain the results of bentonite by considering dissolution and precipitation of minerals and soluble impurities. The dependencies of experimental Kd values on pH, ionic strength and liquid to solid ratio were qualitatively explained by the model. The modeling result for bentonite indicated that sorption of Ra on bentonite is dominated by ion exchange with smectite. The observed pH dependency was caused by changes of Ca concentration arising from dissolution and precipitation of calcite. Diffusion behavior of Ra in bentonite was also investigated as a function of dry density and ionic strength. The apparent diffusion coefficients (Da) obtained in compacted bentonite were in the range of 1.1 x 10(-11) to 2.2 x 10(-12) m2 s-1 and decreased with increasing in dry density and ionic strength. The Kd values obtained by measured effective diffusion coefficient (De) and modeled De were consistent with those by the sorption model in a deviation within one order of magnitude. 相似文献
118.
119.
Akata N Hasegawa H Kawabata H Chikuchi Y Sato T Ohtsuka Y Kondo K Hisamatsu S 《Journal of environmental radioactivity》2007,95(1):1-9
Biweekly atmospheric depositions of (137)Cs were measured in Rokkasho, Aomori, Japan from March 2000 to March 2006 to study recent (137)Cs deposition. Although the deposition level was generally lower than the detectable limit, deposition samples collected in spring occasionally had measurable levels of (137)Cs. The annual (137)Cs deposition from 2001 to 2005 was 0.04-0.69 Bq m(-2) with a mean value of 0.27 Bq m(-2). Depositions of insoluble Al, Fe and Ti were strongly correlated with the (137)Cs deposition, suggesting that suspension of soil particles was the main source of the recent (137)Cs deposition. Asian dust events were coincident with some of the significant (137)Cs depositions in spring. It was found that the ratios of (137)Cs/Al and Fe/Al could be used as indices for discriminating Asian dust from suspension of the local surface soil. Backward trajectory analysis suggested southern Mongolian and northeastern China regions as sources of the significant (137)Cs depositions. 相似文献
120.
Jin Sato 《Sustainability Science》2007,2(2):151-158
The objective of this paper is to trace the evolution of the resource concept in modern Japan by highlighting key individuals
who played major roles in communicating this idea to a wider audience during its formation and development between the 1910s
and 1950s. Special attention will be paid to the effect of different historical contexts on interpretations of the term “resource”.
The paper reveals how the integration of knowledge indispensable for achieving sustainability occurs. The orientation of resource
policy was drastically different before and after World War II. In the pre-war period, the military government used the resource
concept to create a comprehensive inventory of the nation’s military forces, and “resource” was thus a convenient term to
neutralize the aggressive connotations of top-down military mobilization. After the turn to democratic principles in 1945,
“resource” suddenly acquired a symbolic meaning as a means to serve the people. Despite these contrasts, however, pre and
post-war resource concepts share a commonality in that the government acted as the centralizing force, providing a platform
to integrate disparate knowledge under the resource concept. At a time when society itself is more prone to fragmentation,
the resource concept, which played a significant role in unification in the past, should be re-examined. The history of the
concept in Japan, particularly during the pre and post-war period up until the 1950s, contains a wealth of insights as to
how this can be achieved.
相似文献
Jin SatoEmail: |