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961.
Potassium,calcium, and magnesium dynamics during litter decomposition in a cool temperate forest 总被引:3,自引:0,他引:3
The dynamics of K, Ca, and Mg were investigated during the decomposition of 14 litter types over a 3-year period on the upper and lower parts of a forest slope in a cool temperate forest in Japan. Potassium dynamics were divided into initial leaching phase and late phase. Initial K concentrations for the initial phase were correlated with the rate of decrease in K concentration during the initial phase. The late phase was characterized by seasonal fluctuations in concentration: K concentration increased from April to November and decreased during the winter period. The pattern of change in Ca concentration was divided into initial increase phase and late decrease phase in some litter types, or consisted of the late phase only in other litters. Calcium concentration of the initial litter was not predictable for the pattern of change in Ca concentration nor the rate of change in Ca concentration during the initial phase. Initial Ca concentration for the late phase was correlated with the rate of change in Ca concentration during the late phase. The pattern of change in Mg concentration was divided into initial leaching phase and late immobilization phase. Initial Mg concentration for the initial phase was correlated with the rate of change in Mg concentration during the initial phase. At the lower site, initial Mg concentration for the late phase was correlated with the rate of change in Mg concentration during the late phase, while such a relationship was not observed at the upper site. Concentrations of K, Ca, and Mg showed a convergent trend at the end of the study period. The final concentration differed between the upper and lower sites. 相似文献
962.
Soda K Cheng MC Yoshida H Endo M Lee SH Okamatsu M Sakoda Y Wang CH Kida H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(6):767-772
H5N2 viruses were isolated from cloacal swab samples of apparently healthy chickens in Taiwan in 2003 and 2008 during surveillance of avian influenza. Each of the viruses was eradicated by stamping out. The official diagnosis report indicated that the Intravenous Pathogenicity Indexes (IVPIs) of the isolates were 0.00 and 0.89, respectively, indicating that these were low pathogenic strains, although the hemagglutinin of the strain isolated in 2008 (Taiwan08) had multibasic amino acid residues at the cleavage site (PQRKKR/G). In the present study, these H5N2 viruses were assessed for their intravenous and intranasal pathogenicity for chickens. It was examined whether Taiwan08 acquires pathogenicity through consecutive passages in chickens. Intravenous pathogenicity of Taiwan08 depended upon the age of the chickens used for the IVPI test; all of the eight-week-old chickens intravenously inoculated with Taiwan08 showed clinical signs but survived for ten days post inoculation (IVPI=0.68), whereas all the six-week-old chickens died (IVPI=1.86). Taiwan08-P8, which were passaged in chickens for eight times, killed all the eight-week-old chickens (IVPI=2.36). The four-week-old chickens died after intranasal inoculation of Taiwan08-P8, indicating that Taiwan08 must have become highly pathogenic during circulation in chicken flocks. These results emphasize the importance of a stamping out policy for avian influenza even if the IVPI of the causal virus is low. 相似文献
963.
Weina Jiang Satoshi Tan Yusuke Hanaki Kazuhiro Irie Hajime Uchida Ryuichi Watanabe Toshiyuki Suzuki Bryan Sakamoto Michiya Kamio Hiroshi Nagai 《Marine drugs》2014,12(12):5788-5800
The toxin-producing cyanobacterium, Moorea producens, is a known causative organism of food poisoning and seaweed dermatitis (also known as “swimmer’s itch”). Two new toxic compounds were isolated and structurally elucidated from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies, as well as optical rotations and CD spectra indicated two new lyngbyatoxin derivatives, 2-oxo-3(R)-hydroxy-lyngbyatoxin A (1) and 2-oxo-3(R)-hydroxy-13-N-desmethyl-lyngbyatoxin A (2). The cytotoxicity and lethal activities of 1 and 2 were approximately 10- to 150-times less potent than lyngbyatoxin A. Additionally, the binding activities of 1 and 2 possessed 10,000-times lower affinity for the protein kinase Cδ (PKCδ)-C1B peptide when compared to lyngbyatoxin A. These findings suggest that these new lyngbyatoxin derivatives may mediate their acute toxicities through a non-PKC activation pathway. 相似文献
964.
Process water of a pulp mill with extended kraft cooking, two-stage oxygen delignification, and chlorine dioxide bleaching was examined from the aspect of a new standard for environmental water quality in Japan. According to the new standard, the concentration of dioxins – polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, coplanar polychlorinated biphenyls – in environmental water is restricted to less than 1pg TEQ/l. We clarified that the concentrations of the dioxins in sewers in the chlorine dioxide stage and the alkali stage were less than 1pg TEQ/l and that the 2,3,7,8-tetrachlorodibenzofuran concentrations were 0.5pg/l or less. In addition, a main source of 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins in the process water seemed to be an agrochemical in water supplied from a river. 相似文献
965.
Yoichi Miyake Shingo Kimura Tomohiko Kawamura Takashi Kitagawa Motoyuki Hara Hiroshi Hoshikawa 《Fisheries Science》2010,76(4):561-570
Most juveniles of Haliotis discus hannai have been found to be descendants of wild individuals, although most adults were artificially produced (released) individuals
as a result of restocking inside the refugium located near the head of Oshoro Bay, Hokkaido, Japan. To estimate the larval
supply from released and wild individuals into the refugium and to compare the suitability of locations as larval sources,
we simulated larval dispersal using a coupled hydrodynamic and particle-tracking model. The simulation results indicated that
more larvae may be supplied from the wild adults inside the bay to the refugium than from the released adults. These results
are consistent with the observed high abundance of wild juveniles in the refugium. Most larvae from the refugium were predicted
to disperse out of the bay. We found that larval retention in the bay was at least one order of magnitude higher than that
in the refugium. Thus, it may be more effective in terms of self-replenishment and reproduction if the refugium were to be
expanded to the bay scale. There were only minor differences among the compared sites at the head of the bay in terms of their
suitability as larval sources. Consequently, the establishment of new refugia in this area could be expected to provide an
effectiveness equal to that of the current refugium. 相似文献
966.
Suzuki YA Murata Y Inui H Sugiura M Nakano Y 《Journal of agricultural and food chemistry》2005,53(8):2941-2946
The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides. 相似文献
967.
Much evidence has indicated that the occurrence of montmorillonite and vermiculite containing Al-interlayers is very common in solis, particularly acid soils. Viewed in the light of soil clay minerology, it would be required to investigate the properties of their original minerals. For the latter purpose, the Al-interlayer has been removed prior to the Mg-glycerol,K-saturation and heating tests for identification of montmorillonite and vermiculite. Its removal has been accomplished in sevsral ways; KOH plus KCl (1), NH4F, KCl plus HCl (2), Na-citrate (3),400C de hydroxylation-NaOH (4) dissolution. Although these methods are effective for the removal of Al-interlayers, they seem drastically to affect the minerals or are time-consuming. Inthe course of the study of hydroxy-Al interlaid complexes of expanding 2:1 layer lattice clay minerals, the authors have noticed the difference between the (001) spacings of hydroxy-Al complexes of montmorillonite and vermiculite; the former exhibited the 20 A basal spacing at room temperature against the 14 A spacing of the latter. This difference might be useful for differentiating montnmorillonite-chlorite intergrades in soils. 相似文献
968.
969.
Aki Miyashima Tomonari Kotani Hirohito Tawa Hiroshi Fushimi 《Aquaculture Research》2012,43(5):679-687
This work aimed to evaluate the relationship between morphological development, oxygen consumption and reduced mortality in larval fish. We measured the resting metabolic rate (RM), specific metabolic rate (SMR) and the change in the total length during the larval stage of four fish species. Resting metabolism decreased from hatching to mouth opening, and then increased after mouth opening. The changes in the SMR were variable during the larval stage. After hatching, there was no increase in SMR in yolk‐sac larvae. However, SMR increased between mouth opening and the onset of notochord flexion and then decreased during notochord flexion before finally stabilizing. We observed two peaks in mortality during the larval period of all species: between mouth opening to the onset of notochord flexion and from the completion of notochord flexion to the juvenile stage based on the per cent mortality and the number of dead fish collected from the bottom of the rearing tank. Interestingly, the changes in SMR coincided with these periods of mortality. We hypothesize that larvae require more energy during these periods of larval development and are thus more susceptible to mortality when energy is insufficient. Thus, it is important to supply enough nutrition to larvae in during early development to prevent mass larval mortality. 相似文献
970.
Sato H Hirata N Koketsu K Okaya D Abe S Kobayashi R Matsubara M Iwasaki T Ito T Ikawa T Kawanaka T Kasahara K Harder S 《Science (New York, N.Y.)》2005,309(5733):462-464
Devastating earthquakes occur on a megathrust fault that underlies the Tokyo metropolitan region. We identify this fault with use of deep seismic reflection profiling to be the upper surface of the Philippine Sea plate. The depth to the top of this plate, 4 to 26 kilometers, is much shallower than previous estimates based on the distribution of seismicity. This shallower plate geometry changes the location of maximum finite slip of the 1923 Kanto earthquake and will affect estimations of strong ground motion for seismic hazards analysis within the Tokyo region. 相似文献