Total arsenic (As) and its compounds were determined in liver, kidney, muscle, and stomach contents of green turtles (Chelonia mydas). Total As concentrations in the muscle were higher than those in the kidney and liver. Arsenobetaine (AB) was the predominant compound in all the three tissues and its levels were positively correlated with total As concentrations. This indicates that AB greatly contributes to As accumulation in green turtles. Higher concentrations of remaining As in the sample after extraction were detected in the liver, implying that lipid-soluble or protein bound As compounds accumulate in the liver of green turtles. Total As levels in tissues showed significant negative correlations with standard carapace length. The size-dependence of As accumulation in green turtles may be related to their feeding habit, shifting from carnivore to herbivore at different growth stages. Concentrations of AB and dimethylarsinic acid (DMA) were low in the stomach contents but high in the tissues, implying bioaccumulation of these arsenicals in green turtles. 相似文献
We studied the applicability of two types of existing three-dimensional (3-D) basin velocity structure models of the Osaka
basin, western Japan for long-period ground motion simulations. We synthesized long-period (3–20 s) ground motions in the
Osaka basin during a M6.5 earthquake that occurred near the hypothetical Tonankai earthquake source area, approximately 200 km
from Osaka. The simulations were performed using a 3-D finite-difference method with nonuniform staggered grids using the
two basin velocity structure models. To study the ground motion characteristics inside the basin, we evaluated the wave field
inside the basin using the transfer functions derived from the synthetics at the basin and a reference rock site outside the
basin. The synthetic waveforms at the basin site were obtained by a convolution of the calculated transfer function and the
observed waveform at the reference rock site.
First, we estimated the appropriate Q values for the sediment layers. Assuming that the Q value depends on the S wave velocity VS and period T, it was set to Q = (1/3VS)(T0/T) where VS is in m/s and the reference period T0 is 3.0 s. Second, we compared the synthetics and the observations using waveforms and pseudovelocity response spectra, together
with a comparison of the velocity structures of the two basin models. We also introduced a goodness-of-fit factor to the pseudovelocity
response spectra as an objective index. The synthetics of both the models reproduced the observations reasonably well at most
of the stations in the central part the basin. At some stations, however, especially where the bedrock depth varies sharply,
there were noticeable discrepancies in the simulation results of the models, and the synthetics did not accurately reproduce
the observation. Our results indicate that the superiority of one model over the other cannot be determined and that an improvement
in the basin velocity structure models based on simulation studies is required, especially along the basin edges. We also
conclude that our transfer function method can be used to examine the applicability of the basin velocity structure models
for long-period ground motion simulations. 相似文献
The first specimen of Aturoidea to be recorded in East Asia has been found in the Upper Cretaceous Sada limestone in Shimanto City, Kochi Prefecture, Japan. The specimen is one of the few representatives from the Upper Cretaceous, along with species known from Libya, Angola, and India. The specimen is very similar to A. mathewsonni from the Paleocene deposits in California. However, we describe the specimen as A. cf. mathewsonni, as it slightly differs from A. mathewsonni in the shape of the lateral lobe of the suture. The finding reveals that Aturoidea had already lived in waters around East Asia in the Late Cretaceous. 相似文献
Nineteen trace elements were determined in liver, muscle, kidney, gonads, and hair of 18 harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada. Concentrations of V, Mn, Fe, Cu, Mo, Ag, and Hg in the liver, Co, Cd, and Tl in the kidney, and Ba and Pb in the hair were significantly higher than those in other tissues. Significant positive correlations between Hg concentrations in the hair, and liver, kidney and testis imply usefulness of the hair sample for non-destructive monitoring of Hg in the harp seals. It is suggested that whereas Hg preferentially accumulates in the liver, the accumulation in other tissues is induced at higher hepatic Hg levels. In contrast, Se may not be accumulated in other tissues compared with the liver even at higher hepatic Hg levels because of the presence of excess Se for Hg detoxification in other tissues. 相似文献
We discuss dust formation in steady state dust driven winds around oxygen-rich AGB stars, including not only homogeneous Al2O3 and silicate grains but also heterogeneous grains consisting of an Al2O3 core and a silicate mantle. In the inner subsonic region, Al2O3 grains with radii of ∼ 0.15 μm condense first, then condensation of silicate on Al2O3 starts slightly inside the sonic point, which accelerates the gas flow into the supersonic region. Also small silicate grains,
whose radii are a few tens of ?ngstroms form beyond the sonic point. The carrier of 13 μm feature observed towards oxygen-rich
AGB stars is considered to be the core-mantle grains consisting of an α-Al2O3 core and a silicate mantle from the radiation transfer calculations based on the results of dust formation calculations.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs. 相似文献
An extended Vendian-Cambrian island-arc system similar to the Izu-Bonin-Mariana type is described in the Gorny Altai terrane at the margin of the Siberian continent.
Three different tectonic stages in the terrane are recognized. (1) A set of ensimatic active margins including subducted oceanic crust of the Paleo-Asian ocean, the Uimen-Lebed primitive island arc, oceanic islands and seamounts: the set of rocks is assumed to be formed in the Vendian. (2) A more evolved island arc comprising calc-alkaline volcanics and granites: a fore-arc trough in Middle-late Cambrian time was filled with disrupted products of pre-Middle Cambrian accretionary wedges and island arcs. (3) Collision of the more evolved island arc with the Siberian continent: folding, metamorphism and intrusion of granites occurred in late Cambrian-early Ordovician time.
In the late Paleozoic, the above-mentioned Caledonian accretion-collision structure of the Siberian continent was broken by large-scale strike-slip faults into several segments. This resulted in the formation of a typical mosaic-block structure. 相似文献