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排序方式: 共有128条查询结果,搜索用时 31 毫秒
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综合考虑地质学实践课的特点及野外地质实习基地应具备的功能,根据目前我校地质学野外实习基地的现状,提出了合理选择及建设地质学野外教学基地的几点思考.依照吉林大学地球科学院野外地质实习基地建设经验,制定了我校地质野外实习基地的建设原则和初步构想. 相似文献
94.
高校学生干部在党团组织、老师和广大同学中起着桥梁纽带与助手作用,他们所具备的意识和能力,直接关系到学校及各项学生活动的开展.本篇文章首先列举了学生干部应具备的六个基本意识和基本能力,进而结合实践经验从选拔、培训、实践、总结四个方面提出学生干部的培养途径和方法. 相似文献
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96.
Eisuke Ito Takaaki Sato Daisuke Sano Etsuko Utagawa Tsuyoshi Kato 《Food and environmental virology》2018,10(2):201-208
A new computational method for the detection of virus particles in transmission electron microscopy (TEM) images is presented. Our approach is to use a convolutional neural network that transforms a TEM image to a probabilistic map that indicates where virus particles exist in the image. Our proposed approach automatically and simultaneously learns both discriminative features and classifier for virus particle detection by machine learning, in contrast to existing methods that are based on handcrafted features that yield many false positives and require several postprocessing steps. The detection performance of the proposed method was assessed against a dataset of TEM images containing feline calicivirus particles and compared with several existing detection methods, and the state-of-the-art performance of the developed method for detecting virus was demonstrated. Since our method is based on supervised learning that requires both the input images and their corresponding annotations, it is basically used for detection of already-known viruses. However, the method is highly flexible, and the convolutional networks can adapt themselves to any virus particles by learning automatically from an annotated dataset. 相似文献
97.
Natsuko Ito Kondo Daisei Yamanaka Yuya Kanbe Yoko Kawate Kunitake Masahiro Yoneda Koji Tsuchida Koichi Goka 《Die Naturwissenschaften》2009,96(4):467-475
The European bumblebee, Bombus terrestris, is an invasive eusocial species whose distribution is expanding greatly beyond its native range because numerous colonies
are imported to or locally produced in non-native countries for pollination of agricultural crops. Closely related species
exist in Japan where the unrestricted import and use of B. terrestris has resulted in the establishment of wild colonies. Laboratory studies previously showed that B. terrestris and Japanese native species can copulate and produce fertilized eggs. Although these eggs do not hatch, the interspecific
mating can cause a serious reproductive disturbance to native bumblebees. In this study, we determined the frequencies of
interspecies mating between B. terrestris males and native bumblebee queens in the wild on the islands of Hokkaido and Honshu by analyzing the DNA sequences of spermatozoa
stored in spermathecae of native queens. We found that 20.2% of B. hypocrita hypocrita queens and 30.2% of B. hypocrita sapporoensis queens had spermatozoa of B. terrestris males in their spermathecae. Given that a Bombus queen generally mates only once in her life, such high frequencies of interspecific mating with B. terrestris pose serious threats to the populations of native bumblebees in Japan. 相似文献
98.
Yutaka Saito Anthony R. Chittenden Kotaro Mori Katsura Ito Atsushi Yamauchi 《Behavioral ecology and sociobiology》2008,63(1):33-42
The number of nests containing egg masses a female makes over her lifetime and the pattern of scattering nests vary among
species in a genus of nest-weaving spider mites (Stigmaeopsis). We hypothesized that the scattered nests of small nest builders have a previously overlooked indirect effect in that the
void nests created after predation take on a new role as hindering devices that effectively decrease predator searching efficiency.
First, we demonstrated that the experimental design used in this study is a good reflection of the nest distribution pattern
of Stigmaeopsis takahashii (an intermediate-sized nest builder) in the field. Using this species as a model, we tested how different nest-scattering
patterns affect the predator to examine how scattering may indirectly provide an anti-predation strategy by increasing a predators
searching time. Next, we observed how artificially arranged void nests disturb predatory behavior in both starved and fully
fed predator females and showed that void nests have a strong hindering effect on predators. Thus, we concluded that the nesting
behavior of this mite species not only has anti-predator effects but must also have a stabilizing effect on predator–prey
interaction systems at the population level. 相似文献
99.
Nobuhisa Watanabe Saburo Inoue Hisao Ito 《Journal of Material Cycles and Waste Management》2000,2(1):10-15
Antimony volatilization in municipal waste incineration was studied. Two municipal waste samples and antimony(III) oxide (Sb4O6) were heated to 500°C and 700°C in an air stream in a quartz furnace. The volatilization of Sb4O6 occurred more at 700°C that at 500°C. Conversely, antimony volatilization form municipal waste was stronger at 500°C than
at 700°C. This implies that antimony from municipal waste is volatilized as chloride instead of oxide. The chlorine sources
for antimony chlorination, a gas-phase reaction involving hydrochloric acid and a solid-phase reaction of inorganic chlorine,
e.g., CaCl2, were compared. Only the solid-phase reaction could offer enough active chlorine to induce chlorination of antimony oxide.
Received: July 2, 1998 / Accepted: January 28, 1999 相似文献
100.
The photocatalytic degradation of crotamiton in aqueous solution using TiO2 was investigated. To investigate the effect of initial pH, the photodegradation behaviors of three types of pharmaceuticals were compared (crotamiton, clofibric acid, sulfamethoxazole). The degradation rates of crotamiton in the pH range 3-9 were nearly equal, but those of clofibric acid and sulfamethoxazole were affected by pH. At pH > 6.5, TiO2 particles, clofibric acid and sulfamethoxazole had negative charge, therefore, the repulsive force between TiO2 particles and anionic pharmaceuticals occurred and a low reaction rate at high pH was observed. The effect of UV intensity and TiO2 concentration on photodegradation efficiency was also investigated. Linear and logarithmical relationships between UV intensity, TiO2 concentration and the reaction rate constant were confirmed. Furthermore, the structures of photodegradation intermediates formed concomitantly with the disappearance of crotamiton were estimated. Seven intermediates were characterized by LC/MS/MS analyses, and it was assumed that the photocatalytic degradation of crotamiton was initiated by the attack of electrophilic hydroxyl radicals on aromatic rings and alkyl chains. 相似文献