Continuing observation of disturbed reproductive cycle and ovarian spermatogenesis in the giant abalone, Haliotis madaka from an organotin-contaminated site of Japan   总被引：1，自引：0，他引：1  

Horiguchi T  Kojima M  Takiguchi N  Kaya M  Shiraishi H  Morita M 《Marine pollution bulletin》2005,51(8-12):817-822

Histological examination of gonads as well as chemical analysis of organotin compounds in tissues of the giant abalone, Haliotis madaka, was conducted to evaluate continuing endocrine disruption in abalone populations in Japan. Abalone specimens were collected from two different areas, Tsushima as a reference site and Jogashima as a site representative of declining abalone populations where serious organotin contamination had been observed, each month from January 1998 to March 1999. Scores were given to the development stages of reproductive cells in the ovary and testis. The degree of sexual maturation was evaluated by calculating the mean value of a histogram of these scores for the reproductive cells of each abalone. The temporal variations in degree of sexual maturation showed that female and male abalone from Tsushima matured synchronously, while those from Jogashima did not, which were similar to results of the previous study during September 1995–November 1996. Approximately 19% of the female abalone from Jogashima were masculinized with an ovo-testis, which was also similar to the result of the previous study. The masculinization of female abalone is reported to be induced by tributyltin (TBT) and triphenyltin (TPhT) from antifouling paints. Concentrations of the sum of butyltins (TBT, dibutyltin (DBT) and monobutyltin (MBT): ΣBTs) and the sum of phenyltins (TPhT, diphenyltin (DPhT) and monophenyltin (MPhT): ΣPhTs) in the muscle of abalone from Jogashima (n = 73) of 7.8 ± 9.0 ng/g wet wt. and 4.5 ± 6.8 ng/g wet wt., respectively, were significantly higher than those from Tsushima (n = 87) of 4.7 ± 4.9 ng/g wet wt. and 0.8 ± 1.7 ng/g wet wt., respectively (p < 0.05 for ΣBTs; p < 0.001 for ΣPhTs), although concentrations of TBT and TPhT in the muscle of abalone from Jogashima (n = 73) of 2.2 ± 2.5 ng/g wet wt. and 5.8 ± 5.1 ng/g wet wt., respectively, were insignificantly and significantly higher than those from Tsushima (n = 87) of 0.4 ± 0.6 ng/g wet wt. and 0.5 ± 0.9 ng/g wet wt., respectively, (p > 0.05 for TBT; p < 0.001 for TPhT). Thus, endocrine disruption as well as contamination by organotins in the giant abalone from Jogashima is still persisting.  相似文献   

Volumetric mapping of tubeworm colonies in Kagoshima Bay through autonomous robotic surveys     

Toshihiro Maki  Ayaka KumeTamaki Ura 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(7):757-767

We developed and tested a comprehensive method for measuring the three-dimensional distribution of tubeworm colonies using an autonomous underwater vehicle (AUV). We derived volumetric measurements such as the volume, area, average height, and number of tubes for colonies of Lamellibrachia satsuma, the world's shallowest-dwelling vestimentiferan tubeworm discovered at a depth of 82 m, at the Haorimushi site in Kagoshima Bay, Japan, by processing geometric and visual data obtained through low-altitude surveys using the AUV Tri-Dog 1. According to the results, the tubeworm colonies cover an area of 151.9 m², accounting for 5.8% of the observed area (2600 m²). The total number of tubes was estimated to be 99,500. Morphological parameters such as area, volume, and average height were estimated for each colony. On the basis of average height, colonies could be clearly separated into two groups, short (0.1-0.3 m) and tall (0.6-0.7 m), independent of the area.  相似文献   

The Scutum ring ofHii regions     

Toshihiro Handa  Yoshiaki Sofue 《Astrophysics and Space Science》1986,119(1):127-130

A ring of compact radio continuum sources was found atl=24°.6b=0°.0, which we call the Scutum ring. Radio continuum,Hi line, and CO line observations are suggested that it is a star-forming region triggered by an expanding diffuseHii region.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.NRO, a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a cosmic radio observing facility open for outside users.  相似文献   

Compression of Na0.4Mg0.6Al1.6Si0.4O4 NAL and Ca-ferrite-type phases     

Saori Imada  Kei Hirose  Tetsuya Komabayashi  Toshihiro Suzuki  Yasuo Ohishi 《Physics and Chemistry of Minerals》2012,39(7):525-530

Compression behaviors of two Al-rich phases in the lower mantle, hexagonal new aluminum-rich (NAL) phase and its high-pressure polymorph Ca-ferrite-type (CF) phase, were examined for identical Na_0.4Mg_0.6Al_1.6Si_0.4O₄ (40?% NaAlSiO₄–60?% MgAl₂O₄) composition. The volumes of the NAL and CF phases were obtained at room temperature up to 31 and 134?GPa, respectively, by a combination of laser-annealed diamond-anvil cell techniques and synchrotron X-ray diffraction measurements. Fitting of the third-order Birch–Murnaghan equation of state to such pressure–volume data yields bulk modulus K ₀?=?199(6) GPa at 1?bar and its pressure derivative K ₀′?=?5.0(6) for the NAL phase and K ₀?=?169(5) GPa and K ₀′?=?6.3(3) for the CF phase. These results indicate that the bulk modulus increases from 397 to 407 GPa across the phase transition from the NAL to CF phase at 43 GPa, where the NAL phase completely transforms into the CF phase on Na_0.4Mg_0.6Al_1.6Si_0.4O₄. Density also increases by 2.1?% across the phase transition.  相似文献   

Modeling a spatiotemporal distribution of stranded people returning home on foot in the aftermath of a large-scale earthquake     

Toshihiro Osaragi 《Natural Hazards》2013,68(3):1385-1398

On the day of the Tohoku-Pacific Ocean Earthquake (2011), all rail services in the Tokyo Metropolitan area were paralyzed, amid substantial confusion. Consequently, over 3 million persons were unable to return home on that day. Some, unable to contact their families, felt uneasy and set out to return home on foot. Main roads were seriously congested with cars and people, and the use of emergency vehicles was also obstructed. In this paper, we construct several models that describe decision-making and behavior of individuals attempting to reach home on foot in the wake of a devastating earthquake. The proposed models are calibrated using data taken from questionnaire surveys and person-trip surveys, addressed to occupants of the Tokyo Metropolitan area. We attempt to simulate the movement of individuals having decided to return home on foot and demonstrate the spatiotemporal distribution of those who might be exposed to city fires on their way home in the context of such an event.  相似文献   

Shaking table tests of steel frame with superelastic Cu–Al–Mn SMA tension braces          下载免费PDF全文

Yoshikazu Araki  Kshitij C. Shrestha  Nao Maekawa  Yuji Koetaka  Toshihiro Omori  Ryosuke Kainuma 《地震工程与结构动力学》2016,45(2):297-314

Shaking table tests are performed on a one‐bay one‐story steel frame with superelastic Cu–Al–Mn shape memory alloy (SMA) tension braces. The frame is subjected to a series of scaled ground motions recorded during the 1995 Kobe earthquake, Japan. The test results demonstrate that the SMA braces are effective to prevent residual deformations and pinching. It is also shown that the time history responses observed from the shaking table tests agree well with the numerical predictions using a rate‐independent piecewise‐linear constitutive model calibrated to the quasi‐static component tests of the SMA braces. This suggests that the loading rate dependence of Cu–Al–Mn SMAs as well as the modeling error due to the piecewise linear approximation can be neglected in capturing the global response of the steel frame. Numerical simulations under a suite of near‐fault ground motion records are further performed using the calibrated analytical models to demonstrate the effectiveness of the SMA braces when the variability of near‐fault ground motions is taken into account. A stopper, or a deformation restraining device, is also proposed to prevent premature fracture of SMA bars in unexpectedly large ground motions while keeping the self‐centering capability in moderate to large ground motions. The effectiveness of the stopper is also demonstrated in the quasi‐static component and shaking table tests. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Simulating the diurnal cycle of rainfall in global climate models: resolution versus parameterization   总被引：1，自引：1，他引：0  

Paul A. Dirmeyer  Benjamin A. Cash  James L. Kinter III  Thomas Jung  Lawrence Marx  Masaki Satoh  Cristiana Stan  Hirofumi Tomita  Peter Towers  Nils Wedi  Deepthi Achuthavarier  Jennifer M. Adams  Eric L. Altshuler  Bohua Huang  Emilia K. Jin  Julia Manganello 《Climate Dynamics》2012,39(1-2):399-418

The effects of horizontal resolution and the treatment of convection on simulation of the diurnal cycle of precipitation during boreal summer are analyzed in several innovative weather and climate model integrations. The simulations include: season-long integrations of the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) with explicit clouds and convection; year-long integrations of the operational Integrated Forecast System (IFS) from the European Centre for Medium-range Weather Forecasts at three resolutions (125, 39 and 16 km); seasonal simulations of the same model at 10 km resolution; and seasonal simulations of the National Center for Atmospheric Research (NCAR) low-resolution climate model with and without an embedded two-dimensional cloud-resolving model in each grid box. NICAM with explicit convection simulates best the phase of the diurnal cycle, as well as many regional features such as rainfall triggered by advancing sea breezes or high topography. However, NICAM greatly overestimates mean rainfall and the magnitude of the diurnal cycle. Introduction of an embedded cloud model within the NCAR model significantly improves global statistics of the seasonal mean and diurnal cycle of rainfall, as well as many regional features. However, errors often remain larger than for the other higher-resolution models. Increasing resolution alone has little impact on the timing of daily rainfall in IFS with parameterized convection, yet the amplitude of the diurnal cycle does improve along with the representation of mean rainfall. Variations during the day in atmospheric prognostic fields appear quite similar among models, suggesting that the distinctive treatments of model physics account for the differences in representing the diurnal cycle of precipitation.  相似文献   

Structurally preserved Zamites bayeri Kvaček from the Coniacian Kashima Formation (Yezo Group) of Hokkaido,Japan     

Toshihiro Yamada 《Cretaceous Research》2009,30(5):1301-1306

A permineralized frond from the Coniacian Kashima Formation (Yezo Group) of Hokkaido, Japan, is identified as Zamites bayeri based on leaf shape, transverse orientation of stomata, papillate epidermal surface, and hollow subsurface bodies formed only on the abaxial epidermis. The specimen has an articulation at the base of the leaflet from which the leaflet was detached by means of an abscission zone. This finding suggests that Z. bayeri has compound leaves that are functionally equivalent to a twig bearing simple leaves. This functional conversion is often found in extant compound-leaved ferns or cycads growing in infertile conditions; thus Z. bayeri might have lived in a similar habitat. Leaflet articulation is also found in other Zamites species including the type species of the genus, whereas it is unknown in other bennettitalean foliar morphogenera. The rachis of the specimen has a columnar vascular bundle, which is common in bennettitalean foliage.  相似文献   

Lag between the optical and NIR variabilities of NGC 4151     

T. Minezaki  Y. Yoshii  Y. Kobayashi  K. Enya  M. Suganuma  H. Tomita  T. Aoki  B. A. Peterson 《Astronomische Nachrichten》2004,325(3):256-256

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Diurnal variability of thermospheric N and NO     

Toshihiro Ogawa  Yutaka Kondo 《Planetary and Space Science》1977,25(8):735-742

A model for diurnal variations of neutral and ionic nitrogen compounds in the thermosphere is reconstructed on the basis of a new photochemical aspect on N(²D), together with new observations of the NO density. The NO density so far measured must be reduced by a factor 2, due to a revision of the fluorescence coefficient for the NO γ-band airglow. Incorporating the quenching reaction of N(²D) with O in the model calculation results in a reduction of the NO density at heights as low as 100 km. These two effects are combined to lead to an evaluation that the N(²D) quantum yield for various possible reactions is as large as 0.9. A smaller rate coefficient for the quenching reaction than that measured in the laboratory, i.e. 1.0 × 10^?12cm³sec^?1 is favourable for the recent NO observation in the early morning, as well as the observed emission rates of the 5200 A airglow from N(²D) The present model predicts a significant day-to-night variation of N and NO densities at heights above 100 km. Below 100 km, the NO density is fairly stable because of its long chemical time constant. Since the rate coefficient for the conversion of N(⁴S) to NO is highly temperature dependent, the relative population of N(⁴S) and NO is very sensitive to the thermospheric temperature variation. Large variations of both N(⁴S) and NO densities due to the temperature change could occur especially at night. The model is in good agreement with the NO observations so far available in low and middle latitudes, as well as the N observation by the use of a rocket in the twilight.  相似文献