GMS proton flux observation during February 1978     

Tsugunobu Nagai  Masaynki Kuwashima  Makoto Kawamura  Tsuyoshi Kohno 《Planetary and Space Science》1979,27(7):1035-1037

It is suggested that the drop out of the 1.2–4 MeV proton flux, observed by the geostationary satellite GMS, was due to the Earthward shift of the particle boundary in all local time. The particle boundary motions are associated with substorm activities.  相似文献   

Numerical simulation of organic chemicals in a marine environment using a coupled 3D hydrodynamic and ecotoxicological model     

Kim DM  Nakada N  Horiguchi T  Takada H  Shiraishi H  Nakasugi O 《Marine pollution bulletin》2004,48(7-8):671-678

For ecotoxicological risk assessment in a marine ecosystem, we constructed a coupled three-dimensional hydrodynamic and ecotoxicological model (EMT-3D), and applied it to Tokyo Bay. The model was calibrated with field data obtained in 2002. The results of sensitivity analysis for dissolved Bisphenol A showed that biodegradation rate was the most important factor for concentration change. Bioconcentration coefficient was the most important factor for Bisphenol A in phytoplankton. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Bisphenol A in water, in particulate organic carbon and in phytoplankton are 7.85 x 10(4), 1.78 x 10(2) and 3.44 x 10(-1) g, respectively. With respect to flux, biodegradation in the water column had the highest value of 1.06 x 10(3) g/day, and next were effluent to the open sea, partition to particulate organic carbon, and bioconcentration in phytoplankton.  相似文献   

Nitrate and phosphate uptake kinetics ofChattonella antiqua grown in light/dark cycles     

Yasuo Nakamura  Makoto M. Watanabe 《Journal of Oceanography》1983,39(4):167-170

Nitrate and phosphate uptake kinetics ofChattonella antiqua were examined under light and dark conditions. The uptake kinetics ofC. antiqua followed the Michaelis-Menten equation. The maximal uptake rates (V _max) of nitrate and phosphate in the dark were 86 and 93% of those in the light, respectively. The half-saturation constants (K ₈ ) were not significantly affected by illumination and were comparable to those of other phytoplankton. However, specific maximal uptake rates ofC. antiqua for these substrates were much smaller than those of other phytoplankton.  相似文献   

TIDICS—Control of tidal residual circulation and tidal exchange in a channel-basin system     

Makoto Kashiwai 《Journal of Oceanography》1985,41(1):1-10

A self-excited oscillation of tidal flow occurs in a tidal channel-basin system with a narrow and high speed inflowing tidal jet. The mechanism of this oscillation was examined through hydraulic experiments. Results show that the oscillation is caused by alternation in the strength of asymmetric residual circulation caused by a biased supply of vorticity by asymmetric tidal vortex pairs, and that the mechanism of alternation also depends on negative feed-back between the residual circulation and the vorticity supply.The unstable state of the flow suggested the possibility of controlling the tidal current and tidal exchange in the channel-basin system and this was confirmed experimentally. Under fixed tidal conditions and with fixed basin dimensions, the tidal residual circulation was controlled to form two strong clockwise and anticlockwise circulations or a single circulation by changing the shape of the bay entrance.  相似文献   

History and present status of the fishery of Sergestes lucens (Penaeidea, Decapoda, Crustacea) in Suruga Bay, Japan     

Omori  Makoto; Konagaya  Teruo; Noya  Kazuo 《ICES Journal of Marine Science》1973,35(1):61-77

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Productivity of zooplankton in the sea: Problems in relation to study on Sergestes lucens in Suruga Bay     

Makoto Omori 《Journal of Oceanography》1970,26(4):242-252

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Temporal and spatial variations in the spawning activity of the micronektonic shrimp,Sergia lucens (hansen) in Suruga Bay,Japan     

Gretchen H. Bishop  Makoto Omori  Fumio Muranaka 《Journal of Oceanography》1989,45(4):243-250

Temporal and spatial variations in the spawning activity ofSergia lucens were investigated in relation to some environmental conditions of Suruga Bay. The daily egg abundance varied considerably with the coefficient of variation from 81% to 269% in July. The spawning activity was most clearly affected by temperature, but the relationship to lunar period and content of chlorophylla were not obvious. Timing of the July spawning is predictable with increase of the surface temperature to 24°C and strong vertical movements of the 18°C isotherm depth; it is also related to modal length of the shrimp in June. It is suggested that intrusion of cold water at 20–50 m affects reproduction of the shrimps and vertical distribution of eggs and larvae. The shrimp population seemed to relate principally to two spawning grounds,i.e. the head part and the western part of the bay. The timing of spawning is not always synchronous throughout the bay. The spawning is sporadic and the distribution of eggs is patchy. This may reflect a recent decrease in the population of the shrimp due to increased fishing pressure.A part of the present paper is based on the thesis submitted by G. H. B. in partial fulfilment of the requirements for her degree of Master of Science at the Tokyo University of Fisheries in 1986.  相似文献   

The effectiveness of decentralisation reforms in the Philippines’s forestry sector     

Kulbhushan Balooni  Juan M. Pulhin  Makoto Inoue 《Geoforum》2008,39(6):2122-2131

Decentralisation reforms and political conditions in the Philippines present an ideal environment for forest management by recognising the land entitlements of upland and indigenous communities and promoting the involvement of local government units. By assessing whether current conditions – policies, institutions, and programmes – are conducive to effective decentralisation, this study examines the present state of decentralisation in the forestry sector of the Philippines. By analysing case studies conducted in Nueva Vizcaya Province, it also attempts to answer a broader question: when is decentralisation a success and when is it a failure? A number of uncertainties are revealed, along with various issues that hamper decentralisation, and that are interrelated and reinforce one another in much the same way as they have done over the past decade. The study highlights the need for caution when increasing the involvement of government at different levels, as it affects the pace of decentralisation reforms. It also shows that a mix of site-specific interventions and community endeavours that focus on securing local livelihoods has led to some success. This is a strategy that helps decentralisation reforms.  相似文献   

A large-scale excavation in soft Holocene deposit and its elasto-viscoplastic analysis     

Fusao Oka  Naoki Takada  Kazuyuki Shimono  Yosuke Higo  Sayuri Kimoto 《Acta Geotechnica》2016,11(3):625-642

In the present study, the large-scale excavation in the construction is numerically back-analyzed using a soil–water-coupled finite element method with an elasto-viscoplastic model which considers the strain-induced degradation. The measurements of the deformation have been performed during the construction of a new railway station in Osaka, Japan, in which a large and deep excavation has been successfully carried out using a special deep mixing type of soil improvement method with earth retaining walls through the thick Holocene Osaka Umeda clay deposit. A comparison between the numerical results and the measurements of the excavation at Osaka shows that the simulation method can reproduce the overall deformation of the soft ground and the earth retaining walls including the time-dependent behaviour during the excavation and a deep mixing soil improvement method as an additional technique for stability are effective.  相似文献   

Groundwater age rejuvenation caused by excessive urban pumping in Jakarta area,Indonesia     

Makoto Kagabu  Jun Shimada  Robert Delinom  Toshio Nakamura  Makoto Taniguchi 《水文研究》2013,27(18):2591-2604

Rapid urbanization in the Jakarta area has become a severe subsurface environmental issue as it entails groundwater level decline and land subsidence caused by excessive groundwater pumping. In this study, apparent groundwater age rejuvenation in the deep aquifer under DKI Jakarta was found by comparing ¹⁴C activities between 1985 and 2008. We discussed the use of a numerical groundwater flow model to evaluate the rejuvenation process in this urbanized area. When considering the deep aquifer in the DKI Jakarta area, we can assume six direction fluxes toward the aquifer: two vertical fluxes (downward and upward flux) and four horizontal fluxes (northern, southern, western, and eastern flux). Results of model calculations show that the greatest groundwater flux among six flux directions became ‘vertical downward flux’, which means that shallower groundwater intrudes into the deep one because of excessive groundwater pumping from the mid‐1980s. This flux grows about 50% during the 2000s. This result is consistent with the detection of CFC‐12 and SF₆, which functions as an indicator of young groundwater even in the deep groundwater. The rejuvenation ratio ‘R’ was determined using ¹⁴C activity in the groundwater; R increases with the CFC‐12 concentration and both show good correlation. Furthermore, we estimated the ‘vertical downward flux’ at each well's screen depth using model estimation. Results show that this flux is greater in the urban groundwater depression area and especially at shallower parts of the deep aquifer, and that it affects the magnitude of the shallow groundwater intrusion. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献