在节点部署稀疏、环境恶劣和网络不连通等情况下,WSNs(Wireless Sensor Networks)易出现网络孤岛、能量空洞、节能与恶劣环境网络节点部署等问题。针对这些问题,首先结合拓扑控制算法,对基于静态、动态小世界WSNs拓扑控制研究现状分别...在节点部署稀疏、环境恶劣和网络不连通等情况下,WSNs(Wireless Sensor Networks)易出现网络孤岛、能量空洞、节能与恶劣环境网络节点部署等问题。针对这些问题,首先结合拓扑控制算法,对基于静态、动态小世界WSNs拓扑控制研究现状分别进行阐述,并在此基础上着重论述了基于动态小世界WSNs拓扑控制——Data MULEs(Data Mobile Ubiquitous LAN Extensions)的拓扑模型构造、最优轨迹、数据转发流程三个研究方向的算法设计与研究现状,基于此,最后指明了未来应开展的研究工作。展开更多
The scalar of Japanese yew （Taxus cuspidata） population and the relationship between individual distribution and site factors were analyzed according to investigating data in 74 sample belts with a total sampled are...The scalar of Japanese yew （Taxus cuspidata） population and the relationship between individual distribution and site factors were analyzed according to investigating data in 74 sample belts with a total sampled area of 436.872 hm2 in Muling Nature Reserve. The result showed that the distribution rules of Japanese yew population were correlated to elevation, slope position, slope aspect and slope gradient. The optimal distribution range in elevation for the natural Japanese yew population is at the attitudes of 700-800 m. The amounts of Japanese yew individuals on shady slope were more than those on sunny slope. On top slope and mid-slope, the individual amounts of Japanese yew are more than those on toe slope. Most of Japanese yew individuals occurred on slope gradient of less than 15. The scalar of the population was decreased with the slope gradient increasing.展开更多
转座子是一类可以在基因组中不同遗传位点间移动的DNA序列,在其转移过程中有时会伴随自身拷贝数的增加。作为基因组的重要组成部分,转座子可以通过多种方式影响宿主基因及基因组的结构与功能,进而在宿主的演化过程中扮演重要角色。目前...转座子是一类可以在基因组中不同遗传位点间移动的DNA序列,在其转移过程中有时会伴随自身拷贝数的增加。作为基因组的重要组成部分,转座子可以通过多种方式影响宿主基因及基因组的结构与功能,进而在宿主的演化过程中扮演重要角色。目前依据转座过程中间体类型的不同可以将其分为I类转座子和II类转座子。Mutator超家族转座子是20世纪70年代在玉米(Zea may L.)中发现的一类特殊的转座子,其属于II类转座子,广泛存在于真核生物基因组中,包含遗传特征明晰可分的众多转座子家族。此外,该超家族转座子转座频率高,倾向于插入基因富含区及低拷贝序列区,可快速产生大量新的突变体,目前已被广泛应用于正向及反向遗传学研究。本文结合近年来相关研究结果,围绕Mutator超家族转座子的分类组成、结构特征、转座机制、插入偏好、靶位点重复序列以及玉米自主性MULEs元件展开综述,并对转座子研究面临的问题及未来研究方向进行了探讨,旨在与研究领域内的同行探讨相关研究的可能突破点、未来发展方向及可能产生的重大影响。展开更多
[Objective] To explore artificial insemination technique for production of mule ducks. [Method] Female Cherry Valley ducks were artificially inseminated with semen collected from male Muscovy ducks by massage method a...[Objective] To explore artificial insemination technique for production of mule ducks. [Method] Female Cherry Valley ducks were artificially inseminated with semen collected from male Muscovy ducks by massage method and vagina-insemination method to investigate the effects of insemination dose, insemination interval, insemination time and diluents on fertilization rate. [ Result ] The average fertilization rate was only 39.58%, when the female Cherry Valley ducks naturally mated with the male Muscovy ducks. However, it was increased to 74.79% by artificial insemination. The fertilization rate was 75.24% after semen was diluted by PBS buffer, while it was 75.16% after semen was diluted by Lake＇s buffer; however, there was not significant difference between the fertilization rate of the diluted semen and that of fresh semen （74.10%）. After semen was respectively diluted by PBS buffer and Lake＇s buffer and then stored at 5 ℃ for 24 h, the fertilization rate was low, respectively 23.76% and 34133%. [ Conclusion] Artificial insemination technology can reduce insemination dose and increase fertilization rate in production of mule ducks.展开更多
The flexibility offered by an Enterprise Service Bus (ESB) in enabling various applications to exchange data makes it a very important middleware layer that is responsible for transporting data in a Service-Oriented A...The flexibility offered by an Enterprise Service Bus (ESB) in enabling various applications to exchange data makes it a very important middleware layer that is responsible for transporting data in a Service-Oriented Architecture (SOA). The popularity of the ESB has given rise to a number of commercial off the shelf (COTS) products as well as open source ESBs. In this study, we evaluated three open source ESBs and compared them both qualitatively and quantitatively. The empirical results were statistically tested to determine the statistical significance of the results.展开更多
We inventoried plant regeneration and soil compaction along mule trails to evaluate damage to forest stands and regeneration follow- ing mule hauling before and after operations in Kheyrud Forest in the Hyrcanian Fore...We inventoried plant regeneration and soil compaction along mule trails to evaluate damage to forest stands and regeneration follow- ing mule hauling before and after operations in Kheyrud Forest in the Hyrcanian Forest in northern Iran. About 22% of regenerating plants on mule trails were damaged following mule logging, and damage to trees was observed. In harvested units after timber extraction, 4.3% of the total area （12 ha） was covered with mule trails. Mule passes and slope gradi- ent, and twofold interactions between mule passes x slope gradient had no significant effect on soil bulk density （p 〈 0,05）. Mule iogging had a statistically significant effect on soil bulk density along the mule trails before and after mule passes. Soil bulk density increased Significantly as mule passes increased in number. The degree and level of compaction did not differ with trail slope. With respect to damage to residual stands and seedlings, soil compaction and disturbance to soil, traditional mule log- ging is the preferred skidding method in the steep terrain conditions in the Hyrcanian Forest in northern Iran.展开更多
文摘在节点部署稀疏、环境恶劣和网络不连通等情况下,WSNs(Wireless Sensor Networks)易出现网络孤岛、能量空洞、节能与恶劣环境网络节点部署等问题。针对这些问题,首先结合拓扑控制算法,对基于静态、动态小世界WSNs拓扑控制研究现状分别进行阐述,并在此基础上着重论述了基于动态小世界WSNs拓扑控制——Data MULEs(Data Mobile Ubiquitous LAN Extensions)的拓扑模型构造、最优轨迹、数据转发流程三个研究方向的算法设计与研究现状,基于此,最后指明了未来应开展的研究工作。
基金This work was supported by Northeast Forestry University fund Program from Science and Technology Department of Heilongjiang Province (LC05C14)
文摘The scalar of Japanese yew （Taxus cuspidata） population and the relationship between individual distribution and site factors were analyzed according to investigating data in 74 sample belts with a total sampled area of 436.872 hm2 in Muling Nature Reserve. The result showed that the distribution rules of Japanese yew population were correlated to elevation, slope position, slope aspect and slope gradient. The optimal distribution range in elevation for the natural Japanese yew population is at the attitudes of 700-800 m. The amounts of Japanese yew individuals on shady slope were more than those on sunny slope. On top slope and mid-slope, the individual amounts of Japanese yew are more than those on toe slope. Most of Japanese yew individuals occurred on slope gradient of less than 15. The scalar of the population was decreased with the slope gradient increasing.
文摘转座子是一类可以在基因组中不同遗传位点间移动的DNA序列,在其转移过程中有时会伴随自身拷贝数的增加。作为基因组的重要组成部分,转座子可以通过多种方式影响宿主基因及基因组的结构与功能,进而在宿主的演化过程中扮演重要角色。目前依据转座过程中间体类型的不同可以将其分为I类转座子和II类转座子。Mutator超家族转座子是20世纪70年代在玉米(Zea may L.)中发现的一类特殊的转座子,其属于II类转座子,广泛存在于真核生物基因组中,包含遗传特征明晰可分的众多转座子家族。此外,该超家族转座子转座频率高,倾向于插入基因富含区及低拷贝序列区,可快速产生大量新的突变体,目前已被广泛应用于正向及反向遗传学研究。本文结合近年来相关研究结果,围绕Mutator超家族转座子的分类组成、结构特征、转座机制、插入偏好、靶位点重复序列以及玉米自主性MULEs元件展开综述,并对转座子研究面临的问题及未来研究方向进行了探讨,旨在与研究领域内的同行探讨相关研究的可能突破点、未来发展方向及可能产生的重大影响。
文摘[Objective] To explore artificial insemination technique for production of mule ducks. [Method] Female Cherry Valley ducks were artificially inseminated with semen collected from male Muscovy ducks by massage method and vagina-insemination method to investigate the effects of insemination dose, insemination interval, insemination time and diluents on fertilization rate. [ Result ] The average fertilization rate was only 39.58%, when the female Cherry Valley ducks naturally mated with the male Muscovy ducks. However, it was increased to 74.79% by artificial insemination. The fertilization rate was 75.24% after semen was diluted by PBS buffer, while it was 75.16% after semen was diluted by Lake＇s buffer; however, there was not significant difference between the fertilization rate of the diluted semen and that of fresh semen （74.10%）. After semen was respectively diluted by PBS buffer and Lake＇s buffer and then stored at 5 ℃ for 24 h, the fertilization rate was low, respectively 23.76% and 34133%. [ Conclusion] Artificial insemination technology can reduce insemination dose and increase fertilization rate in production of mule ducks.
文摘The flexibility offered by an Enterprise Service Bus (ESB) in enabling various applications to exchange data makes it a very important middleware layer that is responsible for transporting data in a Service-Oriented Architecture (SOA). The popularity of the ESB has given rise to a number of commercial off the shelf (COTS) products as well as open source ESBs. In this study, we evaluated three open source ESBs and compared them both qualitatively and quantitatively. The empirical results were statistically tested to determine the statistical significance of the results.
文摘We inventoried plant regeneration and soil compaction along mule trails to evaluate damage to forest stands and regeneration follow- ing mule hauling before and after operations in Kheyrud Forest in the Hyrcanian Forest in northern Iran. About 22% of regenerating plants on mule trails were damaged following mule logging, and damage to trees was observed. In harvested units after timber extraction, 4.3% of the total area （12 ha） was covered with mule trails. Mule passes and slope gradi- ent, and twofold interactions between mule passes x slope gradient had no significant effect on soil bulk density （p 〈 0,05）. Mule iogging had a statistically significant effect on soil bulk density along the mule trails before and after mule passes. Soil bulk density increased Significantly as mule passes increased in number. The degree and level of compaction did not differ with trail slope. With respect to damage to residual stands and seedlings, soil compaction and disturbance to soil, traditional mule log- ging is the preferred skidding method in the steep terrain conditions in the Hyrcanian Forest in northern Iran.
