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71.
Gymnocanthus is the most widely distributed genus in the family Cottidae, with six species distributed in the high-latitude area of northern hemisphere. To clarify the phylogenetic relationships and to estimate the divergence times of species in the genus, 2,548 bp of the partial sequences of the 12–16S rRNA, cytochrome oxidase subunit I and cytochrome b gene were analyzed. Our results suggest the monophyletic genus, which arose in the Aleutian Archipelago, divided into a shallow-water group and a deep-water group 8.1 million years ago (Ma). G. tricuspis of the shallow-water group firstly migrated from the Pacific to the Arctic Ocean 5.0 Ma when the Bering Strait first opened. A second migration occurred in the late Pliocene to early Pleistocene after which G. pistilliger and G. intermedius diverged 3.9 Ma. Our findings are discussed within an evolutionary and zoogeographic context. 相似文献
72.
In the Japanese pygmy squid Idiosepius paradoxus, females often pick up the spermatangium using their mouth (buccal mass) after copulation. To examine whether the female I. paradoxus directly transfers sperm into the seminal receptacle via this picking behaviour, or removes the spermatangium, we conducted detailed observations of picking behaviour in both virgin and copulated females and compared the sperm storage conditions in the seminal receptacle between females with and without spermatangia picking after copulation in virgin females. In all observations, elongation of the buccal mass occurred within 5 min after copulation. However, sperm volume in the seminal receptacle was not related to spermatangia picking. Observations using slow-motion video revealed that females removed the spermatangia by blowing or eating after picking. These results suggest that picking behaviour is used for sperm removal but not for sperm transfer. Moreover, the frequency of buccal mass elongation was higher in copulated females than in virgin females, consistent with the sequential mate choice theory whereby virgin females secure sperm for fertilisation, while previously copulated females are more selective about their mate. Female I. paradoxus may choose its mate cryptically through postcopulatory picking behaviour. 相似文献
73.
Volatilization behavior of lead from molten slag under conditions simulating municipal solid waste melting 总被引:1,自引:0,他引:1
Hiroyuki Nakada Naoto Mihara Yuuki Kawaguchi Shohichi Osada Dalibor Kuchar Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2008,10(1):19-23
To reutilize molten slag derived from an ash melting process, the lead volatilization mechanism under reducing conditions
was investigated. Reducing conditions were established by introducing a CO-CO2-N2 gas mixture to the reactor or by adding graphite to the molten slag prior to the experiments. As samples, two types of simulated
molten slag composed of CaO-SiO2-Al2O3 mixed with PbO were used and the lead volatilization behavior was studied at 1773 K. It was found that the lead volatilization
rate increased on increasing the amount of reducing agent for both graphite and the CO-CO2 gas mixture. For the CO-CO2 reducing gas mixture, this increase was mainly attributed to PbO conversion to Pb. For the addition of graphite, the increase
in lead volatilization ratio was considered to partially result from PbO conversion to Pb and partially from a reaction of
graphite with SiO2 yielding volatile SiO. The volatile SiO gas was then emitted from the furnace, which brought about a reduction in the SiO2 content of the slag. As a result, the slag viscosity decreased, which led to an enhancement of the lead volatilization ratio. 相似文献
74.
Nguyen Cao Don Hiroyuki Araki Nguyen Thi Minh Hang Hiroyuki Yamanishi Kenichi Koga 《Environment, Development and Sustainability》2008,10(2):219-231
Groundwater is an important resource in the alluvial coastal lowland plains. In the Shiroishi lowland plain, southwestern
Kyushu Island of Japan, land subsidence due to groundwater development has long been recognized as an environmental issue.
Land subsidence can have several negative economic and social implications. In this study, an integrated numerical groundwater
and land subsidence model, which combines a three-dimensional numerical groundwater flow model and a one-dimensional soil
consolidation model, was used to simulate the dynamic groundwater flow and ground subsidence due to pumping. On the other
hand, a groundwater optimization model was also formulated to search for an optimal safe yield of groundwater pumping without
violating physical, environmental, social-economic constraints. The model results reveal that groundwater levels in the aquifers
greatly vary from season to season in response to varying climatic and pumping conditions. Consequently, land subsidence has
rapidly occurred throughout the area with the central prone in Shiroishi plain. The study also proposes a countermeasure against
subsiding process in the area by means of numerical models. The optimization model result suggests that pumping can be increased
in the northern part of the study area without leading to significant land subsidence. 相似文献
75.
Zacharia J. U. Malley Mohammed Taeb Tetsuo Matsumoto Hiroyuki Takeya 《国际发展与全球生态学杂志》2013,20(2):145-159
Natural resources are important assets for sustainability of rural livelihoods and economic development. The objectives of the study were to assess linkage of environmental change to emerging water scarcity, livelihoods insecurity and decline in wildlife biodiversity and hydropower generation in the Great Ruaha ecosystem, and to discuss policy lessons for sustainable development. Literature survey, participatory assessments, collection of records from stakeholders, participatory observations and a questionnaire survey were used. Participatory assessment found that increasing water scarcity is associated with degradation of land, vegetation cover and change in rainfall intensity and duration. Rainfall change is supported by 83% of respondents and rainfall trends analysis. About 42% of variation in cereal production is described by the rainfall amount variability. Analysis of trends for per capita cereals production from district records showed a significant (p < 0.05) decline over the years. Changes in water flows in the Great Ruaha River have been evident since 1993, and have affected wildlife diversity in the Ruaha National Park and power generation from the Kidatu hydroelectric plant downstream. Human livelihood activities, exclusiveness, weak coordination and collaboration between sectors and institutions in policy formulation and implementation have played a role. The pro-poor policy formulation through integrated planning, strong coordination and collaboration is recommended for sustainable development. 相似文献
76.
Degradation of microcystins using immobilized microorganism isolated in an eutrophic lake 总被引:4,自引:0,他引:4
The final purpose of our series of studies is to establish a biological removal method of cyanobacteria and their toxic products using immobilized microorganisms that can lyse cyanobacteria and decompose microcystins. To establish the biological removal method in non-point areas and water purification plants, as the first step, we explored bacteria active against the cyanobacterial hepatotoxin microcystin in the present study. Eleven active bacteria were isolated from samples taken from Lakes Tsukui and Sagami, Japan. Among 3 strains (B-9 to B-11) with degradative activity, strain B-9 exhibited the strongest activity. The 16S rDNA sequence of the strain B-9 showed the highest similarity to that of Sphingomonas sp. Y2 (AB084247, 99% similarity). Microcystins-RR and -LR were completely degraded by strain B-9 (SC16) within 1d, which led to an immobilized microorganism with a polyester resin. The degradation of microcystin-RR in a bioreactor using the immobilized strain B-9 was observed and microcystin-RR (> 90%) was completely degraded after 24 h. Microcystin-RR was added to the lake water at regular intervals and the degradation after 24 h was observed in the bioreactor over a 72-d period. An over 80% removal efficiency continued for 2 months, showing that the life of the immobilized B-9 in terms of activity was at least 2 months under the optimized conditions. From these results, this immobilized B-9 is feasible for the practical treatment of microcystins in non-point areas and water purification plants. 相似文献
77.
Seasonal variation in the atmospheric deposition of inorganic constituents and canopy interactions in a Japanese cedar forest 总被引:1,自引:0,他引:1
Sase H Takahashi A Sato M Kobayashi H Nakata M Totsuka T 《Environmental pollution (Barking, Essex : 1987)》2008,152(1):1-10
The seasonal changes in throughfall (TF) and stemflow (SF) chemistry and the canopy interactions of K+ and N compounds were studied in a Japanese cedar forest near the Sea of Japan. The fluxes of most ions, including non-sea-salt SO4(2-), from TF, SF, and rainfall showed distinct seasonal trends, increasing from autumn to winter, owing to the seasonal west wind, while the fluxes of NH4+ and K+ ions from TF+SF might have a large effect of canopy interactions. The contact angle (CA) of water droplets on leaves decreased with leaf aging, suggesting that surface wettability increases with leaf age. The K+ concentration in TF was negatively correlated with the CA of 1-year-old leaves, while the NH4+ concentration was positively correlated with the CA. The net fluxes of NH4+ and NO3(-) from TF were positively correlated with the CA. The increase in wettability may accelerate leaching of K+ or uptake of NH4+. 相似文献
78.
79.
Mifuyu Ogawa Yuichi Yamaura Shin Abe Daisuke Hoshino Kazuhiko Hoshizaki Shigeo Iida Toshio Katsuki Takashi Masaki Kaoru Niiyama Satoshi Saito Takeshi Sakai Hisashi Sugita Hiroyuki Tanouchi Tatsuya Amano Hisatomo Taki Kimiko Okabe 《Environmental monitoring and assessment》2011,177(1-4):85-94
An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential. 相似文献
80.
TiO2 powder-containing paper composites, called TiO2 paper, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 paper has a porous structure originating from the layered pulp fiber network, with TiO2 powders scattered on the fiber matrix. Under UV irradiation, the TiO2 paper decomposed gaseous acetaldehyde more effectively than powdery TiO2 and a pulp/TiO2 mixture not in paper form. Scanning electron microscopy and mercury intrusion analysis revealed that the TiO2 paper had characteristic unique voids ca. 10 μm in diameter, which might have contributed to the improved photocatalytic performance. TiO2 paper composites having different void structures were prepared by using beaten pulp fibers with different degrees of freeness and/or ceramic fibers. The photodecomposition efficiency was affected by the void structure of the photocatalyst paper, and the initial degradation rate of acetaldehyde increased with an increase in the total pore volume of TiO2 paper. The paper voids presumably provided suitable conditions for TiO2 catalysis, resulting in higher photocatalytic performance by TiO2 paper than by TiO2 powder and a pulp/TiO2 mixture not in paper form. 相似文献