Effects of 17beta-estradiol on the reproduction of Java-medaka (Oryzias javanicus), a new test fish species     

Imai S  Koyama J  Fujii K 《Marine pollution bulletin》2005,51(8-12):708-714

17β-estradiol (E2) is a female hormone which is known to be one of the strongest estrogenic chemicals in the environment. The present study investigated the effects of E2 on the reproduction of the estuarine fish, Java-medaka (Oryzias javanicus). Starting from the embryonic stages, Java-medaka was exposed for 6 months to 9.5, 16, 68, 159 and 243 ng/l of E2. The fecundity of Java-medaka exposed to E2 levels >16 ng/l was significantly lower than that of the control. The appearance of secondary sexual characteristics seemed to be inhibited by exposure to 159 and 243 ng/l E2. Vitellogenin concentrations in the liver of male fish exposed to 68, 159 and 243 ng/l were significantly higher than that of the control. Thirty-three and sixty percent of male fishes exposed to 159 and 243 ng/l, respectively, had testis-ova. These results suggest that reproduction in the Java-medaka, especially the male fish, could be affected by exposure to E2 concentrations greater than 16 ng/l.  相似文献   

Photometric properties of the Arp 220 super star clusters     

Yasuhiro Shioya  Yoshiaki Taniguchi  Neil Trentham 《Monthly notices of the Royal Astronomical Society》2001,321(1):11-17

We investigate the photometric properties of six super stellar clusters (SSCs) seen in both the optical and near-infrared Hubble Space Telescope images of the local ultraluminous starburst galaxy Arp 220. Three of the SSCs are located in the central 0.5-kpc region. The remaining three are in the circumnuclear region between 0.5 and 2.5 kpc from the centre. Comparing the observed spectral energy distributions (SEDs) of the SSCs with the Starburst99 models of Leitherer et al., we confirm that all three nuclear SSCs are heavily obscured     Considering the results from this comparison in conjunction with measurements of the near-infrared CO absorption index and of millimetre CO linewidths and luminosities, we estimate the ages of the nuclear SSCs to be 10⁷–10⁸ yr. The bolometric luminosity of the three nuclear SSCs is at most one-fifth of the total bolometric luminosity of Arp 220. On the other hand, the circumnuclear SSCs have little internal extinction     These contribute negligibly to the total bolometric luminosity.  相似文献   

An on-line adaptation method in a neural network based controlsystem for AUVs     

Ishii  K. Fujii  T. Ura  T. 《Oceanic Engineering, IEEE Journal of》1995,20(3):221-228

A neural network based control system “Self-Organizing Neural-Net-Controller System: SONCS” has been developed as an adaptive control system for Autonomous Underwater Vehicles (AUVs). In this paper, an on-line adaptation method “Imaginary Training” is proposed to improve the time-consuming adaptation process of the original SONCS. The Imaginary Training can be realized by a parallel structure which enables the SONCS to adjust the controller network independently of actual operation of the controlled object. The SONCS is divided into two separate parts: the Real-World Part where the controlled object is operated according to the objective, and the Imaginary-World Part where the Imaginary Training is carried out. In order to adjust the controller network by the Imaginary Training, it is necessary to introduce a forward model network which can generate simulated state variables without involving actual data. A neural network “Identification Network” which has a specific structure to simulate the behavior of dynamical systems is proposed as the forward model network. The effectiveness of the Imaginary Training is demonstrated by applying to the heading keeping control of an AUV “Twin-Burger”. It is shown that the SONCS adjusts the controller network-through on-line processes in parallel with the actual operation  相似文献   

Continuous Measurements of Ground-Water Seepage Using an Automatic Seepage Meter   总被引：6，自引：1，他引：6  

Makoto Taniguchi  Yoshiaki Fukuo 《Ground water》1993,31(4):675-679

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Propagation of slip along frictional surfaces     

Yoshiaki Ida 《Pure and Applied Geophysics》1978,116(4-5):943-953

The propagation of slip along a pre-existing frictional plane is formulated for the faults containing interstitial fluid. When normal and shear stresses satisfy the effective frictional law, a frictional sliding occurs stably or unstably, depending on the inhomogeneities of the surface. For a slip to rapidly sweep the surface, the pore pressure of fluid must exceed the critical value that is related to the physical or geometrical irregularities of the surface. If this condition fails, stable sliding is expected, analogous to a seismic fault creep. This prediction makes the role of water in seismic faulting more clear.  相似文献   

Interionic repulsive force and compressibility of ions     

Yoshiaki Ida 《Physics of the Earth and Planetary Interiors》1976,13(2):97-104

The compressibility of an individual ion is examined, in comparison with a known set of data for the alkali halides. A simple extrapolation of ionic radius to high pressure is not acceptable, because the pressure derivative of ionic radius changes for different salts. According to the classical concept of an elastic ion, the repulsive potential energy between the ions i and j is specified by the nature of each ion as: as a function of the interionic distance r. In this expression, q_i and ρ_i are the ionic radius and ionic compressibility, respectively, in a suitably modified meaning. Such a form of the repulsive potential fits well to the data of lattice constants and bulk moduli. The parameters q_i and ρ_i are evaluated for alkali and halogen ions, and an anion turns out to be much more compressible than a cation. The present treatment may be usefully applied to the minerals in the Earth's mantle, which contain only a few major ions.  相似文献   

Late quaternary uplift in eastern Indonesia     

H.D. Tjia  Shoji Fujii  Kunihiko Kigoshi  Arata Sugimura 《Tectonophysics》1974,23(4):427-433

Radiocarbon dates of fifteen samples representing raised shorelines on various islands of the tectonically mobile region of eastern Indonesia suggest rates of tectonic uplift ranging up to 12.5 mm/year. Low rates of 0.35–1.2 mm/year are from Biak Island and are averages for the last 31,000–36,000 years. The low rates may be explained to indicate subsidence alternating with uplift, both of which occurring under influence of the large Irian fault zone that passes to the immediate south of the island. Very young elevated strandlines (250 years BP) indicate rates of uplift between 8 and 12.5 mm/year which seem to demonstrate the episodic character of vertical diastrophic movements. Intermediate rates of uplift are in the order of 5 mm/year and may represent averages for eastern Indonesia.  相似文献   

Damage to coastal villages due to the 1992 Flores Island earthquake tsunami     

Yoshinobu Tsuji  Hideo Matsutomi  Fumihiko Imamura  Minoru Takeo  Yoshiaki Kawata  Masafumi Matsuyama  Tomoyuki Takahashi  Sunarjo  Prih Harjadi 《Pure and Applied Geophysics》1995,144(3-4):481-524

A field survey of the 1992 Flores Island earthquake tsunami was conducted during December 29, 1992 to January 5, 1993 along the north coast of the eastern part of Flores Island. We visited over 40 villages, measured tsunami heights, and interviewed the inhabitants. It was clarified that the first wave attacked the coast within five minutes at most of the surveyed villages. The crust was uplifted west of the Cape of Batumanuk, and subsided east of it. In the residential area of Wuring, which is located on a sand spit with ground height of 2 meters, most wooden houses built on stilts collapsed and 87 people were killed even though the tsunami height reached only 3.2 meters. In the two villages on Babi Island, the tsunami swept away all wooden houses and killed 263 of 1,093 inhabitants. Tsunami height at Riang-Kroko village on the northeastern end of Flores Island reached 26.2 meters and 137 of the 406 inhabitants were killed by the tsumani. Evidence of landslides was detected at a few points on the coast of Hading Bay, and the huge tsunami was probably formed by earthquake-induced landslides. The relationship between tsunami height and mortality was checked for seven villages. The efficiencies of trees arranged in front of coastal villages, and coral reefs in dissipating the tsunami energy are discussed.  相似文献   

Internal structures and U–Pb ages of zircons from a tuff layer in the Meishucunian formation, Yunnan Province, South China     

Yusuke Sawaki  Manabu Nishizawa  Takeshi Suo  Tsuyoshi Komiya  Takafumi Hirata  Naoto Takahata  Yuji Sano  Jian Han  Yoshiaki Kon  Shigenori Maruyama 《Gondwana Research》2008,14(1-2):148

The Precambrian/Cambrian (PC/C) boundary is one of the most important intervals for the evolution of life, represented by prominent biological evolution from the first appearance of soft-bodied animals from the late Neoproterozoic to the sudden diversification of animals with mineralized skeletons in the Cambrian. In South China several areas contain many fossils and are well exposed, suitable for the investigation of PC/C boundary. However, geochronological relationships are still poorly known because of lack of combined detailed investigations of internal structures of zircons and in-situ U–Pb dating.We focus on the internal structure of zircons from a tuff layer within Bed 5 in the Meishucun section on which we undertook cathodoluminescence (CL) imaging and in-situ U–Pb dating with LA-ICP-MS and nano-SIMS. Over 600 zircons from the tuff layer were classified into three types based on their CL images: oscillatory rims, inherited cores and dull structures. U–Pb dating of the internal structure of the zircons by LA-ICP-MS clearly shows a distinct unimodal age population dependent on the structure: 531 ± 17 Ma for the oscillatory rims and 515 Ma for the dull structures. The clear oscillatory zonation, the prismatic morphology, and their occurrence indicate that the oscillatory rims were formed from felsic magmatism, and that the U–Pb nano-SIMS age of 536.5 ± 2.5 Ma records the depositional age of the tuff. Our results indicate that the PC/C boundary is situated below Bed 5, and therefore the bottom of Zone 1 (Marker A) is more appropriate for the PC/C boundary than is the top of Zone 1 (Marker B). The age of a positive anomaly (P2) in the early Cambrian is estimated to be ca. 536 Ma.  相似文献   

Interannual-decadal variability of wintertime mixed layer depths in the North Pacific detected by an ensemble of ocean syntheses     

Toyoda  Takahiro  Fujii  Yosuke  Kuragano  Tsurane  Kosugi  Naohiro  Sasano  Daisuke  Kamachi  Masafumi  Ishikawa  Yoichi  Masuda  Shuhei  Sato  Kanako  Awaji  Toshiyuki  Hernandez  Fabrice  Ferry  Nicolas  Guinehut  Stéphanie  Martin  Matthew  Andrew Peterson  K.  Good  Simon A.  Valdivieso  Maria  Haines  Keith  Storto  Andrea  Masina  Simona  Köhl  Armin  Yin  Yonghong  Shi  Li  Alves  Oscar  Smith  Gregory  Chang  You-Soon  Vernieres  Guillaume  Wang  Xiaochun  Forget  Gael  Heimbach  Patrick  Wang  Ou  Fukumori  Ichiro  Lee  Tong  Zuo  Hao  Balmaseda  Magdalena 《Climate Dynamics》2017,49(3):891-907

Climate Dynamics - The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an...  相似文献