CI Aquilae: a recurrent nova with an unusually long plateau phase     

K. Matsumoto  R. Ishioka  M. Uemura  T. Kato  T. Kawabata 《Monthly notices of the Royal Astronomical Society》2003,339(4):1006-1010

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A simplified analysis method for piled raft and pile group foundations with batter piles     

Pastsakorn Kitiyodom  Tatsunori Matsumoto 《国际地质力学数值与分析法杂志》2002,26(13):1349-1369

A simplified method of numerical analysis has been developed to estimate the deformation and load distribution of piled raft foundations subjected to vertical, lateral, and moment loads, using a hybrid model in which the flexible raft is modelled as thin plates and the piles as elastic beams and the soil is treated as springs. Both the vertical and lateral resistances of the piles as well as the raft base are incorporated into the model. Pile–soil–pile, pile–soil–raft and raft–soil–raft interactions are taken into account based on Mindlin's solutions for both vertical and lateral forces. The validity of the proposed method is verified through comparisons with several existing methods for single piles, pile groups and piled rafts. Workable design charts are given for the estimation of the lateral displacement and the load distribution of piled rafts from the stiffnesses of the raft alone and the pile group alone. Additionally, parametric studies were carried out concerning batter pile foundations. It was found that the use of batter piles can efficiently improve the deformation characteristics of pile foundations subjected to lateral loads. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

First findings of decapod crustacea in the hadal zone     

A.J. Jamieson  T. Fujii  M. Solan  A.K. Matsumoto  P.M. Bagley  I.G. Priede 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(4):641-647

Since the first major hadal sampling efforts in the 1950s, crustaceans of the order Decapoda have been thought absent from the hadal zone (6000–11,000 m) with no representatives documented >5700 m. A baited video lander deployed at 6007, 6890 and 7966 m in the Kermadec Trench, 8798 and 9729 m in the Tonga Trench (SW Pacific), 6945 and 7703 m in the Japan Trench and 5469 m in the Marianas region (NW Pacific) has now revealed a conspicuous presence of the Benthesicymid prawn Benthesicymus crenatus Bate 1881. Decapods were observed at all sites except at 7966 m in the Kermadec Trench and the two Tonga Trench sites, making the deepest finding 7703 m in the Japan Trench, 2000 m deeper than previously thought. These natantian decapods were readily attracted to fish bait and, rather than feeding on the bait itself, were observed preying upon smaller scavenging amphipods. These are the first observations of predation in the hadal zone. In less than 10 h of bottom time, 12 observations of 10 individuals were documented at 6007 m and 5 observations of 3 individuals were documented at 6890 m in the Kermadec Trench. In the Japan Trench at 6945 m 29 observations of 20 individuals were documented whilst only one individual was seen at 7703 m. Two individuals were observed in the abyssal Marianas Region (5575 m). Also, in the Kermadec Trench, individual caridean prawns (Acanthephyra spp.) were observed at 6007 and 6890 m, proving categorically that the crustacean order of Decapoda is represented in the hadal zone.  相似文献   

Morphodynamic effects of vegetation life stage on experimental meandering channels     

Tomoko Kyuka  Satomi Yamaguchi  Yusuke Inoue  Kattia Rubi Arnez Ferrel  Hideto Kon  Yasuyuki Shimizu 《地球表面变化过程与地形》2021,46(7):1225-1237

Previous studies have demonstrated that riparian vegetation leads to channel transformation from a multi-bar to a single-thread channel planform. However, it still remains unclear how the presence of pioneer and mature vegetation affects the morphodynamics of single-thread meandering rivers. In this study, we therefore investigated the effects of vegetation strength on the morphodynamic evolution of an experimental meandering channel. Three physical laboratory experiments were conducted using alfalfa sprouts in different life stages – no vegetation, immature vegetation, and mature vegetation – to simulate different floodplain vegetation strengths. Our results demonstrate that vegetation plays a key role in mediating bank erosion and point-bar accretion, and that this is reflected in both the evolution of the channel bed as well as the sediment flux. The presence of mature vegetation maintained a deep, single-thread channel by reducing bank erosion, thereby limiting both channel widening and sediment storage capacity. Conversely, an unvegetated floodplain led to channel widening and high sediment storage capacity. Channel evolution in the unvegetated scenario showed that the active sediment supply from outer bank erosion led to slightly delayed point-bar accretion on the inner banks due to helical flow, deflecting the surface flow toward the outer banks and causing further erosion. In contrast, in the immature vegetation scenario, the outer banks were also initially eroded, but point-bar accretion did not clearly progress. This led to a greater width-to-depth ratio, resulting in a transition from a single- to a multi-thread channel with minor flow paths on the floodplain. The experimental results suggest that the eco-morphodynamic effects of young (low-strength) and mature (high-strength) vegetation are different. Notably, low-strength, early-stage vegetation increases channel complexity by accelerating both channel widening and branching, and therefore might promote the coexistence of multi-bars and pioneer vegetation.  相似文献   

Climate change impacts on international seaports: knowledge, perceptions, and planning efforts among port administrators     

Austin Becker  Satoshi Inoue  Martin Fischer  Ben Schwegler 《Climatic change》2012,110(1-2):5-29

Seaports are located in vulnerable areas to climate change impacts: on coasts susceptible to sea-level rise and storms or at mouths of rivers susceptible to flooding. They serve a vital function within the local, regional, and global economy. Their locations in the heart of sensitive estuarine environments make it an imperative to minimize the impacts of natural hazards. Climate impacts, like a projected SLR of .6?m to 2?m and doubling of Category 4 and 5 hurricanes by 2100, will result in more extreme events at many seaports. To assess the current state of knowledge on this issue, we surveyed port authorities from around the world about how administrators felt climate change might impact their operations, what sea-level change would create operational problems, and how they planned to adapt to new environmental conditions. The planned rapid expansion of ports reported by the survey respondents indicates that adaptation measures should be considered as ports construct new infrastructure that may still be in use at the end of the century. Respondents agreed that the ports community needs to address this issue and most felt relatively uninformed about potential climate impacts. Although most ports felt that SLR would not be an issue at their port this century, sea-level rise was nevertheless an issue of great concern. Our results suggest opportunities for the scientific community to engage with port practitioners to prepare proactively for climate change impacts on this sector.  相似文献   

Distribution and photo-physiological condition of phytoplankton in the tropical and subtropical North Pacific     

Tetsuichi Fujiki  Kazuhiko Matsumoto  Toshiro Saino  Masahide Wakita  Shuichi Watanabe 《Journal of Oceanography》2013,69(1):35-43

To better understand the vertical distribution of phytoplankton in the tropical and subtropical North Pacific, we used fast repetition rate fluorometry to investigate the photo-physiological condition of the phytoplankton assemblage in this region between February and March 2007. Along 155°E, between the equator and 24°N, the peak of fluorescence (F _m), an indication of the deep chlorophyll maximum (DCM), was deeper than the top of the nitracline and occurred at the 2.4 ± 1.3 % (mean ± SD) light depth (relative to 0 m). The photochemical efficiency (F _v/F _m) and effective absorption cross-section of photosystem II (σ_PSII) were low at the surface but increased rapidly at depths between the top of the nitracline (40–138 m) and the DCM (70–158 m), an indication that the photo-physiological condition of the phytoplankton improved below the top of the nitracline. The depth of the maximal F _v/F _m [Z(F _v/F _{m max})] was 18–32 m deeper than the DCM and corresponded to the 0.8 ± 0.2 % light depth. The values of F _v/F _m at the Z(F _v/F _{m max}) were 20 % higher than those at the DCM and averaged 0.48 ± 0.01. These results suggest that the phytoplankton assemblage beneath the DCM had a high potential photosynthetic performance capacity and was growing by using the very low ambient light in this region.  相似文献   

Temporal variations in ozone concentrations derived from Principal Component Analysis     

S. Yonemura  S. Kawashima  H. Matsueda  Y. Sawa  S. Inoue  H. Tanimoto 《Theoretical and Applied Climatology》2008,92(1-2):47-58

Summary The application of principal components and cluster analysis to vertical ozone concentration profiles in Tsukuba, Japan, has been explored. Average monthly profiles and profiles of the ratio between standard deviation and the absolute ozone concentration (SDPR) of 1 km data were calculated from the original ozone concentration data. Mean (first) and gradient (second) components explained more than 80% of the variation in both the 0–6 km tropospheric and 11–20 km troposphere–stratosphere (interspheric) layers. The principal components analysis not only reproduced the expected inverse relationship between mean ozone concentration and tropopause height (r ² = 0.41) and that in the tropospheric layer this is larger in spring and summer, but also yielded new information as follows. The larger gradient component score in summer for the interspheric layer points to the seasonal variation of the troposphere–stratosphere exchange. The minimum SDPR was at about 3 km in the tropospheric layer and the maximum was at about 17 km in the interspheric layer. The tropospheric SDPR mean component score was larger in summer, possibly reflecting the mixing of Pacific maritime air masses with urban air masses. The cluster analysis of the monthly ozone profiles for the 1970s and 2000s revealed different patterns for winter and summer. The month of May was part of the winter pattern in the 1970s but part of the summer pattern during the 2000s. This statistically detected change likely reflects the influence of global warming. Thus, these two statistical analysis techniques can be powerful tools for identifying features of ozone concentration profiles. Authors’ addresses: S. Yonemura, S. Kawashima, S. Inoue, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-0031, Japan; H. Matsueda, Y. Sawa, Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan; H. Tanimoto, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.  相似文献   

Termes seculaires dans la theorie des perturbations     

Takeshi Inoue 《Celestial Mechanics and Dynamical Astronomy》1984,34(1-4):185-191

The convergence property is examined for the series which appear in the theory of the planetary motions. With another point of view, we obtain a result different from that already given by Gyldén: The almost divergency in the meaning of category is concluded when the ratio of the mean motions is irrational using as Gyldén the continuous fractions. The author explains the reason why the series are always useful in practical applications: Because the long evolution of the system of interest under the influence of the small irreversible effects has led to many resonances or quasi-resonances, i.e. conditions favorable to a good convergence of suitable series.  相似文献   

Erratum: Large-amplitude variables near the Galactic Centre     

I. S. Glass  S. Matsumoto  B. S. Carter  K. Sekiguchi 《Monthly notices of the Royal Astronomical Society》2002,336(4):1390-1390

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Characteristics of SeaMARC II phase data     

Matsumoto  H. 《Oceanic Engineering, IEEE Journal of》1990,15(4):350-360

The dispersion of SeaMARC II phase-difference samples is discussed. They appear to be a function of signal direction, range, noise level, and backscatter strength of the bottom. Field data from a lava flow area and from sedimented areas at different depths are compared. The temporal distribution of the phase-difference samples was skewed and asymmetrical about the model. The angular distribution was symmetrical about the mode, with some phase wrap-around. The field data show the presence of a complicated noise interference field. The amount of phase-difference dispersion was larger than that calculated by using a simple Gaussian isotropic noise model, possibly suggesting an additional phase-dispersion process caused by bottom roughness. The method used to produce bathymetry data from the phase-difference samples was evaluated in light of the phase-difference sample distribution  相似文献