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Permanence and Global Stability for Two-Species Cooperative System with Time Delays in Two-Patch Environment

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生物数学学报 1997年第2期12卷 104-110页

作者： Zhang Jingru(Department of Mathematics,Xinjiang University,Urumchi 830046) 新疆大学数学系新疆乌鲁木齐 830046

A two-species nonautonomous delayed system is considered,which models two-population dispersal between two patches of a heterogeneous environment. It is shown that the systerm is permanent under some appropriate condi... 详细信息

关键词： Time delay dispersal permanence global asymptotic stability

A Selection Algorithm of Service Providers for Optimized Data Placement in Multi-Cloud Storage Environment

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国际计算机前沿大会会议论文集 2015年第1期 25-27页

作者： Wenbin Yao Liang Lu Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia Beijing University of Posts and TelecommunicationsBeijingChina

The benefits of cloud storage come along with challenges and open issues about availability of services, vendor lock-in and data security, etc. One solution to mitigate the problems is the multi-cloud storage, where the selection of service providers is a key point. In this paper, an algorithm that can select optimal provider subset for data placement among a set of providers in multicloud storage architecture based on IDA is proposed, designed to achieve good tradeoff among storage cost, algorithm cost, vendor lock-in, transmission performance and data availability. Experiments demonstrate that it is efficient and accurate to find optimal solutions in reasonable amount of time, using parameters taken from real cloud providers.

关键词： cloud storage multi-cloud service provider selection data placement information dispersal algorithm

CLAY MINERALS IN THE CHINA SEA AND ADJACENT SEAS

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Science China Chemistry 1989年第9期32卷 1144-1152页

作者：何良彪 Institute of Oceanography State Oceanic Administration. Qingdao

The clay minerals in the surface sediments from 354 stations have been analyzed qualita-tively and semiquantitatively. The obtained data are dealt mathematically. According to thecalculated results, the distribution laws and the trends of content changes of clay mineralsare discussed. The studied area is divided into four main provinces of sediments with differ-ent sources. Finally the author approached the laws of the migration and dispersal of thefine-grained matter carried into the seas by the Huanghe River, the Changjiang River, theZhujiang River and the Philippine Archipelagoes, and set up the transport model of the fine-grained matter in the China Sea and adjacent seas.

关键词： the China Sea clay minerals trend surface provenauce model of migration and dispersal

Subcanopy genetics —The relationship between canopy tree size and genetic variation of the savanna species Pollichia campestrisAiton (Illecebraceae)

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Open Journal of Ecology 2014年第2期4卷 60-65页

作者： Josef Simmel Peter Poschlod Christoph Reisch Institute of Botany University of Regensburg Regensburg Germany

In savanna vegetation, trees and their canopies provide an important, but scattered habitat. Seeds of plants growing under these nurse trees often are dispersed by animals, especially birds. In the present study, we investigated the influence of tree size and frugivore dispersal on the genetic variation of the subcanopy species Pollichia campestris, using amplified fragment length polymorphisms (AFLP). Considering the individuals under each nurse tree as subpopulations, we found the genetic variation within subpopulations to be positively correlated with the size of the respective canopy tree. Genetic variation was very low among, but high within subpopulations (ΦPT = 0.026, P = 0.18). We conclude that the low genetic variation among subpopulations is due to effective and directed dispersal (dispersal from one canopy to another) by legitimate and frugivorous dispersal agents.

关键词： Acacia AFLP Directed dispersal Frugivore Kalahari Nurse Tree

Germination,Vigor of Seeds and Emergence of Fabaceae Seedling in Bovine Faeces

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American Journal of Plant Sciences 2014年第14期5卷 2170-2177页

作者： Renata Vianna Lima Henrique Duarte Vieira Francielle de Souza Guimaraes Nardele Moreno Rohem Jr. Tatiana Oliveira da Silva Alberto Magno Fernandes Cynthia Pires Guimaraes Amanda Justino Acha Bruno Borges Deminicis Department of Fitotecnia State University of North Fluminense Darcy Ribeiro(UENF)Campos dos GoytacazesRio de JaneiroBrazil Department of Zootecnia State University of North Fluminense Darcy Ribeiro(UENF)Campos dos GoytacazesRio de JaneiroBrazil

This study was conducted to evaluate the physiological quality of forage seeds after passage through the gastrointestinal tract of cattle, as well as the emergence of seedlings derived from these seeds. Three Fabaceae species were used: tropical kudzu, leucaena and calopo. One hundred grams of seeds of each species were offered, separately, to five bovines. After the start of the dispersion, the faeces of the animals were collected every 6 hours, in a total of 72 hours, being taken to the greenhouse immediately after each collection. The study evaluated the total number of seedlings in the stool, the lengths of roots and aerial parts, as well as the natural and dry seedling weight thirty days after the disposal of the faeces in the greenhouse. The experimental design consisted of randomized blocks, with twelve treatments (sampling periods) and five replications (cattle). The best performance for the total number of seedlings in the faeces of cattle was observed in the kudzu species. The length of the root, length of the aerial part and dry matter seedling weight was observed in the leucaena species, followed by kudzu. The calopo showed low results for all variables due to the high degradation of the seeds.

关键词： Pueraria phaseoloides Leucaena leucocephala Calopogonium mucunoides dispersal Physiological Quality

Chemical Analysis on Mongolia’s Natural Bitumen

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Advances in Chemical Engineering and Science 2014年第2期4卷 184-188页

作者： Erdenetsogt Bat-Erdene Batdelger Byambagar Erdenee Enkhtsetseg Budeebazar Avid Institute of Chemistry and Chemical Technology Mongolian Academy of Science Ulaanbaatar Mongolia School of Material Science of the Mongolian University of Science and Technology Ulaanbaatar Mongolia

To extract pure bitumen, the bitumen from Bayan-Erkhet, Zuunbayan and Ukhaa was prepared into small particles of 0.2 - 0.5 cm and then it was infused with chloroform in the Soxhlet apparatus [1] [2]. The physical-mechanical properties were identified after the solvent was extracted from the chloroform infused bitumen through the vacuum evaporation method. The characteristics of the debris without bitumen or the remains after the infusion were examined in details. The hydrocarbon content of the bitumen was identified with the device: Agilent 7890-5975c Gas chromatography mass spectrometer.

关键词： Hydrocarbon dispersal Tar Asphalt Oil

Potential Inbreeding in a Small Population of a Mass Flowering Species, Xanthorrhoea johnsonii(Xanthorrhoeaceae): Is Your Mother My Father?

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American Journal of Plant Sciences 2012年第3期3卷 303-312页

作者： Rachel King Jacinta M. Zalucki Department of Mathematics and Computing Faculty of Sciences University of Southern Queensland Toowoomba Australia School of Environment Griffith University Nathan Australia

Xanthorrhoea johnsonii is a long lived slow growing perennial understorey species, that produces a large quantity of passively dispersed seed every 3 - 5 years. Reproductive maturity is not reached until 20 - 30 years of age. The temporal asynchrony of the flowering event in this population was analogous to geographic isolation through fragmentation. A small population of plants flowering in isolation provided the opportunity to examine outcrossing rates, genetic diversity and the paternity of progeny at a small spatial scale (0.2 ha). The geographic location and physical characteristics of the adult plants were recorded, and both adults and their seed were sampled for genetic analysis. Four microsatellite loci were screened for genetic diversity and spatial structure analysis. A population outcrossing rate was estimated, as well as the number of paternal parents required to resolve the progeny multilocus genotypes. High genetic diversity was found in both adults and progeny with an estimated 97% outcrossing rate. All maternal lines required several paternal contributors, with no evidence of dominant paternal genotypes. Pollen transfer occurred between both geographically close and distant plants.

关键词： Xanthorrhoeaceae Inbreeding Mass Flowering Microsatellite Paternity Outcrossing Pollen dispersal Genetic Structure Isolated Population Xanthorrhoea johnsonii

Understanding the Mechanism of Gamete Release in Sargassum vulgareC. Agardh

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American Journal of Plant Sciences 2012年第9期3卷 1266-1271页

作者： Inderdeep Kaur Reeta Kumari Environmental Biology Laboratory Department of Botany University of Delhi Delhi India SGTB Khalsa College Department of Botany University of Delhi Delhi India

Sargassum vulgare C. Agardh shows androgynous receptacles, each bearing on an average 12 unisexual conceptacles which open outside by ostiole, and wherein gametangia (antheridia or oogonia) lie interspersed with paraphyses. Since out-put of eggs is extremely low, 4 - 6 per female conceptacle, Sargassum sp. ensures its survival under all eco-physiological conditions. The released oogonium is “wrapped” in sulphated polysaccharide-rich wall layer known to provide protection against desiccation. Oogonia after being “extruded” out of ostiole, are “incubated” on receptacle, where they grow into eggs that are easily contacted by spermatozoids. Gamete release is synchronous and almost simultaneous ensuring high rates of fertilization. The release occurs on days falling near a full moon or new moon, during low tides when conceptacles lie exposed. Gamete release occurs first from upper conceptacles, which “house” mature gametangia while lower ones are still developing. This results in gamete release over an extended period of time. The zygote dispersal and propagule recruitment also show adaptations selectively advantageous for the alga.

关键词： Gamete Release Mesochiton Stalk Oogonium Incubation Propagule dispersal Sargassum vulgare