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排序方式: 共有62条查询结果,搜索用时 703 毫秒
1.
Shigekazu Hirao Hiromi Yamazawa Jun Moriizumi 《Journal of environmental radioactivity》2010,101(11):974-984
When used with an atmospheric transport model, the 222Rn flux distribution estimated in our previous study using soil transport theory caused underestimation of atmospheric 222Rn concentrations as compared with measurements in East Asia. In this study, we applied a Bayesian synthesis inverse method to produce revised estimates of the annual 222Rn flux density in Asia by using atmospheric 222Rn concentrations measured at seven sites in East Asia. The Bayesian synthesis inverse method requires a prior estimate of the flux distribution and its uncertainties. The atmospheric transport model MM5/HIRAT and our previous estimate of the 222Rn flux distribution as the prior value were used to generate new flux estimates for the eastern half of the Eurasian continent dividing into 10 regions.The 222Rn flux densities estimated using the Bayesian inversion technique were generally higher than the prior flux densities. The area-weighted average 222Rn flux density for Asia was estimated to be 33.0 mBq m−2 s−1, which is substantially higher than the prior value (16.7 mBq m−2 s−1). The estimated 222Rn flux densities decrease with increasing latitude as follows: Southeast Asia (36.7 mBq m−2 s−1); East Asia (28.6 mBq m−2 s−1) including China, Korean Peninsula and Japan; and Siberia (14.1 mBq m−2 s−1). Increase of the newly estimated fluxes in Southeast Asia, China, Japan, and the southern part of Eastern Siberia from the prior ones contributed most significantly to improved agreement of the model-calculated concentrations with the atmospheric measurements. The sensitivity analysis of prior flux errors and effects of locally exhaled 222Rn showed that the estimated fluxes in Northern and Central China, Korea, Japan, and the southern part of Eastern Siberia were robust, but that in Central Asia had a large uncertainty. 相似文献
2.
When using stable enzyme genes from a thermophile to create a biosensor in Escherichia coli, it is vital that these genes be overexpressed in order to provide a sufficient supply of enzymes. In this study, overexpression of the NADH oxidase (Nox) gene from the thermophile Deinococcus geothermalis was successfully achieved with the aim of creating a stable biosensor active at room temperatures. To do so, modification of 10 nucleotides, GAAATTAACT, upstream of the start codon of the Nox gene was necessary. 相似文献
3.
When using stable enzyme genes from a thermophile to create a biosensor in Escherichia coli, it is vital that these genes be overexpressed in order to provide a sufficient supply of enzymes. In this study, overexpression of the NADH oxidase (Nox) gene from the thermophile Deinococcus geothermalis was successfully achieved with the aim of creating a stable biosensor active at room temperatures. To do so, modification of 10 nucleotides, GAAATTAACT, upstream of the start codon of the Nox gene was necessary. 相似文献
4.
Ha T.T. Dinh Hiromi Kambar Shuji Matsushit Yoshiteru Aoi Tomonori Kindaichi Noriatsu Ozaki Akiyoshi Ohashi 《环境科学学报(英文版)》2022,34(6):68-78
Methane is produced in a microbial electrosynthesis system (MES) without organic substrates. However, a relatively high applied voltage is required for the bioelectrical reactions. In this study, we demonstrated that electrotrophic methane production at the biocathode was achieved even at a very low voltage of 0.1 V in an MES, in which abiotic HS− oxidized to SO42− at the anodic carbon-cloth surface coated with platinum powder. In addition, microbial community analysis revealed the most probable pathway for methane production from electrons. First, electrotrophic H2 was produced by syntrophic bacteria, such as Syntrophorhabdus, Syntrophobacter, Syntrophus, Leptolinea, and Aminicenantales, with the direct acceptance of electrons at the biocathode. Subsequently, most of the produced H2 was converted to acetate by homoacetogens, such as Clostridium and Spirochaeta 2. In conclusion, the majority of the methane was indirectly produced by a large population of acetoclastic methanogens, namely Methanosaeta, via acetate. Further, hydrogenotrophic methanogens, including Methanobacterium and Methanolinea, produced methane via H2. 相似文献
5.
The actual standard in vitro fertilization (IVF) protocol recommends an overnight gamete co-incubation. All of the culture media used for human IVF are supplemented with serum or albumin. In the present study, we determined the concentrations of perfluorinated chemicals (PFCs) in IVF media (IVFM) and related samples by liquid chromatography with tandem mass spectrometry (LC/MS/MS). The results indicated that the concentrations of PFOS and PFOA in the protein source were higher than those in the IVFM samples. Compared with human plasma concentrations of PFCs, PFCs in all of the IVFM samples, such as PFBS, PFHxS and PFOA, were either not detected or present at only trace levels, even when protein source was added. LC/MS/MS could be used to determine PFCs in IVFM samples in future studies of the effects of PFC exposure on intrauterine insemination. 相似文献
6.
7.
I. Nishiumi Satoshi Yamagishi Hiromi Maekawa Chikashi Shimoda 《Behavioral ecology and sociobiology》1996,39(4):211-217
In many polygynous animals, parents invest more heavily in individual sons than in daughters. However, it is unclear if these
differences in investment are a consequence of sex differences in the demand of offspring related to sexual size dimorphism
or a consequence of parental manipulation. Here, we report on parental food delivery frequency in relation to brood size and
brood sex ratio in a wild population of polygynous great reed warblers Acrocephalus arundinaceus. We used the polymorphic microsatellite loci on the Z chromosome to sex chicks. We found that paternal feeding frequency
(times/h per nest) increased not with brood size, but with the proportion of males in the brood, although the demand per nest
was more closely related to brood size than to brood sex ratio. Additionally, the increase in rate of paternal feeding frequency
in relation to the brood sex ratio was much higher than the increase in rate of nestling food demands. Maternal feeding frequency
was independent of both brood size and brood sex ratio. These results strongly suggest that fathers preferentially invest
in their sons. We propose that parents can afford sex-biased parental care in animals in which food provisioning is enough
for all offspring to survive.
Received: 22 January 1996/Accepted after revision: 30 June 1996 相似文献
8.
Isoprene emission from tropical trees in Okinawa Island, Japan 总被引:1,自引:0,他引:1
Tambunan P Baba S Kuniyoshi A Iwasaki H Nakamura T Yamasaki H Oku H 《Chemosphere》2006,65(11):2138-2144
This study surveyed isoprene emission from 42 indigenous and exotic tropical trees in subtropic Okinawa, Japan. Of the 42 trees studied, 4 emitted isoprene at a rate in excess of 20 μg g−1 h−1, and 28 showed the rates of 1–10 μg g−1 h−1. The remainder emitted less than 1 μg g−1 h−1. The majority of trees in this study may therefore fall within the lower emitting species. However, species in Moraceae that is indigenous in Okinawa emitted isoprene at relatively higher rates with an average of 14.2 μg g−1 h−1. The highest emission rate of 107.1 μg g−1 h−1 for Ficus virgata yielded the area basis rate of 47.4 nmol m−2 s−1, which is almost equivalent to the rate of high emitting species. Furthermore, a linear relationship between light intensity and isoprene emission was noted with Ficus virgata up to 1700 μmol m−2 s−1. These findings may show the potential importance of subtropical areas as sources of isoprene to the atmosphere. 相似文献
9.
10.
A growing body of large-N cross-national studies has identified key predictors of environmental behavior. Adopting a social dilemma perspective, where individuals must choose collective over self-interest to act pro-environmentally, integrated national datasets for 30 countries are used to examine the effects of generalized trust, trust in government, leftism, and post-materialism on three types of environmental behavior (intended action, informal action, and formal action). At the individual level, all predictors but institutional trust have significant positive effects on each type of behavior. Institutional trust is associated with greater willingness to make economic sacrifice for the environment and with less frequent informal environmental behavior, but it is unrelated to formal behavior. However, at the country level, the effect of trust is limited to intended behavior and depends on the type of trust. Individuals in countries with higher generalized trust averages are less willing to sacrifice for the environment, and those in countries with higher averages of institutional trust are more willing to do so. 相似文献