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21.
Potential for microbially mediated redox transformations and mobilization of arsenic in uncontaminated soils 总被引:1,自引:0,他引:1
Shigeki Yamamura Mirai Watanabe Norio Yamamoto Kazunari Sei Michihiko Ike 《Chemosphere》2009,77(2):169-174
Surface soil samples, which had no significant As contamination, were examined for As(V) reduction, As(III) oxidation and As mobilization capability. All five soil samples tested exhibited microbial As(V)-reducing activities both in aerobic and anaerobic conditions. Under aerobic conditions when As(V) reduction had almost ceased, oxidation of As(III) to As(V) occurred, whereas only As(V) reduction was observed under anaerobic conditions. In cultures incubated with As(III), As(III) was oxidized by indigenous soil microbes only under aerobic conditions. These results indicate that microbial redox transformations of As are ubiquitous in the natural environment regardless of background As levels. Mobilization through microbially mediated As(V) and Fe(III) reduction occurred both in the presence and absence of oxygen. Significant variation in dissolved As occurred depending on the Fe contents of soils, and re-immobilization of As arose in the presence of oxygen, presumably as a consequence of dissolved As(III) and Fe(II) oxidation. There was no apparent correlation between dissolved Fe(II) and As, suggesting that reductive dissolution of Fe(III) minerals does not necessarily determine the extent of As release from soils. 相似文献
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23.
Designing new institutions for implementing integrated disaster risk management: key elements and future directions 总被引:2,自引:0,他引:2
The goal of integrated disaster risk management is to promote an overall improvement in the quality of safety and security in a region, city or community at disaster risk. This paper presents the case for a thorough overhaul of the institutional component of integrated disaster risk management. A review of disaster management institutions in the United States indicates significant weaknesses in their ability to contribute effectively to the implementation of integrated disaster risk management. Our analysis and findings identify eight key elements for the design of dynamic new disaster management institutions. Six specific approaches are suggested for incorporating the identified key elements in building new institutions that would have significant potential for enhancing the effective implementation of integrated disaster risk management. We have developed a possible blueprint for effective design and construction of efficient, sustainable and functional disaster management institutions. 相似文献
24.
Norio Tanaka Teruko Demise Mitsuhiro Ishii Yasumasa Shoji Masahiro Nakaoka 《Marine Biology》2011,158(4):871-882
Massive losses of eelgrass Zostera marina beds in Japan have occurred over the past 100 years. Toward their restoration, transplantation of eelgrass has been attempted
in some areas, including Tokyo Bay. This study examined population genetic structures and gene flow in eelgrass in Tokyo Bay
to establish guidelines for conducting restoration. Genotypes of a total of 360 individuals from 12 beds were determined using
five microsatellite markers. The eelgrass beds in inner bay had above-average genetic diversity. A neighbor-joining tree based
on F
ST values among beds revealed that a strong gene flow had occurred among six beds in the inner bay. Genetic assignment testing
of drifting shoots indicated that those with seeds migrate in both directions between the inner and outer bay. We suggested
that the restoration of eelgrass in the innermost part of Tokyo Bay, where natural habitats have been lost, should be conducted
using the inner bay beds. 相似文献
25.
Norio Miyamoto Tomoko Yamamoto Yoichi Yusa Yoshihiro Fujiwara 《Die Naturwissenschaften》2013,100(3):285-289
Bone-eating worms of the genus Osedax exclusively inhabit sunken vertebrate bones on the seafloor. The unique lifestyle and morphology of Osedax spp. have received much scientific attention, but the whole process of their development has not been observed. We herein report the postembryonic development and settlement of Osedax japonicus Fujikura et al. (Zool Sci 23:733–740, 2006). Fertilised eggs were spawned into the mucus of a female, and the larvae swam out from the mucus at the trochophore stage. Larvae survived for 10 days under laboratory conditions. The larvae settled on bones, elongated their bodies and crawled around on the bones. Then they secreted mucus to create a tube and the palps started to develop. The palps of O. japonicus arose from the prostomium, whereas the anterior appendages of other siboglinids arose from the peristomium. The recruitment of dwarf males was induced by rearing larvae with adult females. Females started to spawn eggs 6 weeks after settlement. 相似文献
26.
Dutch disease and policy adjustments to the oil boom: A comparative study of Indonesia and Mexico 总被引:1,自引:0,他引:1
Norio Usui 《Resources Policy》1997,23(4):151-162
Dutch disease and, more recently, resource curse thesis have been critical issues for development of resource abundant economies. This paper attempts a comparison between Indonesia and Mexico in their policy adjustments to the oil boom with special reference to the Dutch disease. There exists a striking contrast, especially in their fiscal, foreign borrowing, and exchange rate policies, and confirms the conventional understanding that a booming government should be conservative, as was the case in Indonesia, in its macroeconomic management to avoid the Dutch disease. Equally significant, investment use of oil revenues to strengthen the tradable sector is another factor responsible for Indonesian success. Mexico provides a clear-cut example of the resource curse thesis, but Indonesia is an exception. 相似文献
27.
Dr. Naomichi Matsumoto Nakamichi Saito Naoki Harada Kiyoji Tanaka Norio Niikawa 《黑龙江环境通报》1995,15(7):675-677
DNA-based prenatal carrier detection of group A xeroderma pigmentosum (XP-A) is reported. Chorionic villus sampling was done at the tenth gestational week in a pregnant woman whose first child suffers from XP-A. Genomic DNAs from the villi, proband, and parents were PCR (polymerase chain reaction)-amplified using three sets of primers, because the PCR and a subsequent enzyme digestion with HphI, AlwNI, or MseI may detect the three most frequent mutations of the XP-A complementing gene (XPAC) in Japanese XP-A patients. The results showed that the proband is a homozygote and that the parents and fetus are heterozygotes for a base substitution at the 3′ acceptor site of intron 3 of XPAC, indicating that the fetus is a healthy carrier of XP-A. This is the first case of prenatal carrier detection of the disorder. 相似文献
28.
Metabolites of methoxychlor such as 2-(p-hydroxyphenyl)-2-(p-methoxyphenyl)-1,1,1-trichloroethane (mono-OH-MXC) and 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane (bis-OH-MXC), have estrogenic activity. Mono-OH-MXC is a chiral compound in which the carbon atom bridging two benzene rings is the chiral centre. In previous studies the estrogenic activity of racemic mono-OH-MXC has been measured, and the activity of each enantiomer of this compound has not yet been elucidated. In this study, we evaluated the estrogen receptor-binding activity of each enantiomer of mono-OH-MXC to clarify the enantioselective recognition by the estrogen receptor. (S)-mono-OH-MXC showed 3-fold higher binding activity than that of the (R) enantiomer. The activity of bis-OH-MXC was only 1.7-fold higher than that of (S)-mono-OH-MXC. This result suggests that the one hydroxy group and the orientation of the CCl3 group of mono- and bis-OH-MXCs are important for the interaction with the estrogen receptor. The result also points out the estrogenic activity of methoxychlor after metabolic activation in vivo, which predominantly produces the (S)-mono-OH-MXC, may be higher than estimated from the in vitro activity of racemic mixtures. 相似文献
29.
Conditions under which plants help herbivores and benefit from predators through apparent competition 总被引:1,自引:0,他引:1
Yamamura N 《Ecology》2007,88(6):1593-1599
Leaf domatia are tiny structures in leaf vein axils that are typically inhabited by predatory and fungivorous mites. A recent article reported plant domatia specifically suited for herbivorous mites, which seems paradoxical, since the plant is thus supporting a natural enemy that can harm itself. The authors claimed that domatia are created to promote herbivorous mites as "fodder" for predatory mites that attack another herbivorous mite damaging the plant, and that the relationship among the plant, the fodder mite, and the predatory mite constitute a multiway mutualism because all three species benefit from the interaction. I formulate this system using two simple mathematical models of apparent competition, which differ in how domatia are modeled, and then assess when it is advantageous for the plant to create such space for a natural enemy. As a necessary condition for mutualism, the product of reproductive efficiency and nutritious value of the fodder prey should exceed that of the pest prey. This condition is also sufficient, if the direct costs for making the structure of domatia are negligible. If there are significant costs, however, the condition is broader for predators with lower reproductive efficiency and higher mortality, and for non-fodder prey with high consumption rate and low predation rate. I suggest that creating domatia is more effective when predators are less prolific and non-fodder prey are more severe as pests. Finally, I discuss how this mathematical model can apply to a wider range of tritrophic mutualistic relationships such as those among plants, aphids, and ants. 相似文献
30.
Tsukimori K Uchi H Mitoma C Yasukawa F Chiba T Todaka T Kajiwara J Yoshimura T Hirata T Fukushima K Wake N Furue M 《Environment international》2012,38(1):79-86