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1.
Managing a rare species can be improved with knowledge of its natural history. The sheepnose (Plethobasus cyphyus) is a freshwater mussel recently listed by the US as federally endangered. We used standard methods to study P. cyphyus brooding behaviour, host fishes in the laboratory and under natural conditions, and glochidial morphology. We monitored a population of P. cyphyus in the Chippewa River, WI during spring and summer 2007–2009 and 2011 and found brooding animals between mid-May and early August. Gravid individuals ranged between 5 and 27 yr (mean age ± 1 s.d. = 13 ± 4 yr). Plethobasus cyphyus brooded glochidia in outer gills, which varied in colour from red, orange, pink, cream, or white. We observed mature glochidia more commonly in individuals with cream or white gills and these glochidia were released in a clear, adhesive, mucus matrix. In laboratory trials we found several minnow and topminnow species (29 spp.) served as productive suitable native hosts. The mean number of juvenile mussels released per cyprinid per day was significantly higher for trials conducted at 22–25°C compared with those at 18–20°C, and 83% of trials conducted at 18–20°C using suitable host species produced no juveniles. Glochidia had a unique outline and shell morphometrics that distinguished P. cyphyus from seven other Chippewa River mussel species that produce similar sized glochidia. Using morphometrics we determined that mimic shiners (Notropis volucellus) were natural hosts for P. cyphyus, round pigtoe (Pleurobema sintoxia), and Wabash pigtoe (Fusconaia flava). Releasing mucus-bound glochidia has evolved in a variety of mussel species and may be more common than is currently realized. Our data show that P. cyphyus is a cyprinid host specialist, and propagation efforts for this species can be strengthened through improved access to mature glochidia by using females with cream-coloured gills and increased juvenile production through warmer fish holding temperatures.  相似文献   
2.
在移动计算环境中,断连后,移动客户机根据缓存的数据在本地执行事务,重新连接后,移动客户机中的事务作为暂态事务提交给固定主机重新执行.如果移动客户机与固定主机的读/写、写/写冲突机率很高,则暂态事务在固定主机上成功提交的概率就很低,大量的暂态事务就会夭折,这将浪费大量的服务器资源和通信资源,从而降低整个系统的性能.为了提高暂态事务重提交的成功概率,本文提出按概率提交暂态事务的方法.该方法在冲突频率非常高的场合,能够节省移动客户机的传送开销,减轻固定主机的负担,提高事务的吞吐量.  相似文献   
3.
Summary

The male and female reproductive systems, gut and Malpighian tubules, and ventral nerve cord are described and figured for Orsodacne cerasi L. and Syneta betulae F.; the first instar larva of O. lineola is described and figured, and compared with already described larvae of Syneta betulae and other Chrysomelidae. The adhesive setae of the adult tarsi are described for both species and for representatives of Aulacoscelinae, Megascelinae, Megalopodinae, Sagrinae, Eumolpinae, Hispinae and Camptosomata. The mouthparts of adult Orsodacne and Aulacoscelis are described and figured, with consideration of pollen-eating adaptations in the family. It is concluded that Orsodacne is an isolated and primitive type whose nearest existing relative may be Cucujopsis Crowson in Australia, while Syneta may be allied to both Eumolpinae and Galerucinae. A new key to subfamilies of chrysomelid larvae is provided, and a phyletic dendrogram of the family is figured and discussed.  相似文献   
4.
在移动计算环境中,断连后,移动客户机根据缓存的数据在本地执行事务,重新连接后,移动客户机中的事务作为暂态事务提交给固定主机重新执行.如果移动客户机与固定主机的读/写、写/写冲突机率很高,则暂态事务在固定主机上成功提交的概率就很低,大量的暂态事务就会夭折,这将浪费大量的服务器资源和通信资源,从而降低整个系统的性能.为了提高暂态事务重提交的成功概率,本文提出按概率提交暂态事务的方法.该方法在冲突频率非常高的场合,能够节省移动客户机的传送开销,减轻固定主机的负担,提高事务的吞吐量。  相似文献   
5.
《Journal of Natural History》2012,46(21-22):1369-1385
ABSTRACT

Two new pill millipede species, namely Hyleoglomeris hoanglien sp. nov. and H. fanxipan sp. nov., are described from high elevations (approximately 2,800–2,900 m) of the Hoang Lien National Park, northern Vietnam. A new species, H. hoanglien sp. nov. is clearly distinguished by the telopods being short, stout and incrassate, femora strongly condensed, tibia without modifications, syncoxital lobe bifid trapeziform, and syncoxital horns with an apical seta and a spine. Hyleoglomeris fanxipan sp. nov., is diagnosed by the telopods being long and robust, tibia without modifications, syncoxital lobe roundly trapeziform, and syncoxital horns truncated at tip. COI-based DNA barcodes of the two species are also provided for the first time in the genus Hyleoglomeris. The K2P genetic distance between the two new species is 0.148. In addition, an identification key to the Vietnamese Hyleoglomeris species is also provided.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:6DEFED42-0D65-4F50-9D24-A0923B9D1709  相似文献   
6.
7.
用最大QoS共享路径算法改进MRSVP协议   总被引:2,自引:0,他引:2  
在分析MRSVP(Resource Resercation Protocol with Mobile Hosts)协议的基础上,针对MRSVP协议在处理单播流时的缺陷,提出了最大QoS(Quaity of Service)共享路径的概念,给出了计算最大QoS共享路径的算法并对MRSVP协议进行了改进.分析结果表明,改进后的MRSVP协议相对改进前,在网络重载情况下,缩短了重新进行资源预留的路径,从而提高了资源预留成功率,增加了移动主机在子网间切换的成功率,缩短了移动主机切换的时间.  相似文献   
8.
通过仲裁者连接网络的关键部分和非关键部分,提出主机隐藏技术,并结合如何防止被动探听、主动探索及随意攻击等三种攻击者获取信息方式来解决拒绝服务的问题.  相似文献   
9.
Three new tenuipalpid species are described and illustrated from Hungary: Cenopalpus cumanicus sp. nov., Cenopalpus adventicius sp. nov. and Tenuipalpus budensis sp. nov. (Acari: Tenuipalpidae). The authors give an account of one new record of Cenopalpus spinosus (Donnadieu, 1875) found on woody host plants, a species that has not previously been recorded in the Hungarian fauna. Additional species encountered during these surveys are: Brevipalpus lewisi (McGregor, 1949), Cenopalpus pulcher (Canestrini and Fanzago, 1876), Pentamerismus oregonensis McGregor, 1949, and Pentamerismus taxi (Haller, 1877).  相似文献   
10.
《Journal of Natural History》2012,46(7):1105-1126
The mangroves of the Andaman and Nicobar Islands were extensively surveyed for their insect herbivore—natural enemy complex. A total of 197 species of herbivores, 43 species of hymenopterous parasitoids and 36 species of predators were found in the mangals of these islands. This forms the most extensive listing of herbivorous insects definitely associated with mangroves in the Indian region. In addition to some species that are probably mangrove specialists we have found some serious pests of crop plants which utilise various species of mangroves as alternative host plants. We also present consolidated lists of the insect phytophages so far recorded from the mangals of the Andaman and Nicobar Islands and mainland India.  相似文献   
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