关键词： 计算机视觉   八元树   旋转  

摘要： 在计算机视觉中,八元树是三维物体表示的一种重要形式,本文利用线性八元树结构,提出一种通过平移处理代替旋转的方法,有效地解决了运动物体八元树表示中复杂的旋转问题。首先建立高层节点旋转后的标准八元树,低层的标准八元树可由高层标准八元树直接推出,然后将同层各节点的旋转变为该层标准八元树的平移。这种方法处理速度高,节省了存贮空间.

摘要： Although there has been much recent interest in ant-plant mutualisms, few data are available on the effects of foraging ants on herbivore numbers and levels of herbivory on plants that do not offer specific inducements to attract ant visitation. In forestry plantations and tropical crops, ants have erratic but sometimes dramatic effects on the numbers of insect herbivores but, in more natural habitats, their effects on levels of herbivory appear to be largely unknown. In Australia, where ants and Eucalyptus woodlands are ubiquitous and abundant and where considerable debate has occurred regarding levels of herbivory in Eucalyptus forests, very little work has been done to examine the effects of ants on densities of insect herbivores on eucalypts. In this study, ants were experimentally excluded from mature and immature foliage of saplings of the mallee Eucalyptus incrassata in South Australia, and herbivore numbers and levels of leaf herbivory were assessed during the next 6 months. No significant differences in herbivory were found between ant-access and ant-exclusion treatments. In spring and early summer, ants were found in associations with aggregations of eurymelid bugs on young foliage, and the effects of ants on bug densities were experimentally investigated. Bug densities decreased rapidly in ant-exclusion treatments compared with ant-access controls. Ants also quickly removed seeds of E. incrassata from experimental caches. The potential of ants to limit the numbers of insect herbivores on eucalypts seems limited given their tendency to form mutualistic associations with sap-feeding Homopterans and because of a lack of other herbivores that are particularly vulnerable to ant predation.

关键词： 树Qu   实验动物   体温   昼夜节律  

摘要： 对树鼩、大鼠、小鼠、豚鼠、家兔及家鸽体温的昼夜变动节律进行了比较观察树鼩、大鼠、小鼠、家鸽体温昼夜变动幅度较大。昼夜节律明显;豚鼠、家兔体温昼夜变动幅度较小.树鼩、家鸽的体温昼夜节律呈现昼行动物的相位特征,前者的峰、谷值分别位于19:00和5:00,后者的峰,谷值分别倍于15:00和5:00.大鼠体温的昼夜节律呈现典型的夜行性特征,其峰、谷值分别位于0:00和10:00.同为夜行动物的小鼠的体温昼夜节律、相位与大鼠不同。谷值位于8:00—0:00,其余时间几乎稳定于相同水平.豚鼠、家兔体温昼夜节律表现昼行性特点.

摘要： A community of small rodents was studied in thicket-clump and grassland savanna of Lengwe National Park, Malawi, from September 1984 to June 1985. Nine species were recorded on a 1.1 ha grid and five assessment lines, using a capture-mark-release technique. The three commonest species (and their percentage proportions) were Mastomys natalensis (47%), Acomys spinosissimus (24%) and Saccostomus campestris (11%). Population numbers on the grid fluctuated from 1-30 individuals/ha, and the numbers on the assessment lines fluctuated from 4-57 individuals. There were two peaks of population numbers during the year: the first was in the early wet season (when individuals emigrated from dry season refugia and there was limited reproduction) and the second was in the mid dry season (when young born at the end of the wet season entered the trappable population). The population was comprised mainly of subadults in the late dry season, adults and some young in the wet season, and young and subadults in the early and mid dry seasons. Population survival rates were low with only 30-50% of individuals surviving to the following month. The magnitude of population fluctuations are related to the strong seasonality of climate, flooding and grass characteristics;in this respect, the community of small mammals in Lengwe National Park shows similarities to those of the Kafue Valley in Zambia and the Chobe Valley in Botswana.

关键词： FIRE   OAK SAVANNA   TREE BARK   ARTHROPOD FAUNA   NORTH-AMERICA  

摘要： The arthropod communities living on the bark of the oak species Quercus macrocarpa and Q. ellipsoidalis were investigated in a North American oak savanna. Differences were found in the community structure of the arthropods living on the bark of these two tree species, although they have the same fissured bark type. In the North American oak savanna ecosystem the most important disturbance factor is fire, which maintains species richness. Highest numbers of species and specimens were found at moderately disturbed sites. Three main ecological groups of arthropods living on the bark of trees can be distinguished in relation to the degree of disturbance: (1) Inhabitants of bark of trees restricted to undisturbed sites: they do not occur in fire-disturbed areas;(2) Inhabitants of bark of trees adapted to a moderate degree of disturbance: many species occur in high numbers only in moderately disturbed areas;and (3) Specialist inhabitants of bark of trees in heavily disturbed areas. The number of specimens of these species increases per trunk with the frequency of disturbance.

关键词： 树鼩   实验动物   灵长   结构形态   进化程度  

摘要： 一种被国际公认的高级实验动物树鼩,在我校动物实验中心饲育成功,并用于中德合作课题研究。树鼩(Twpaia belangeris,Tree shrew)国际通称为村仙(Twpaia Glis)。

关键词： 乙型肝炎病毒   乙肝疫苗   树鼩  

摘要： 接种乙肝疫苗的10只树鼩,9只血清出现抗-HBs。注射含HBV的人血清后,其中只有1只血清出现短暂的HBsAg,保护率为88.88％;其血清抗-HBc始终阴性。未接种乙肝疫苗的10只对照树鼩注射HBV人血清后,5只血清HBsAg阳性;8只抗-HBc阳性。接种疫苗组HBV感染率显著低于对照组(p<0.01)。实验前所有树鼩血清HBsAg、抗-HBs及抗-HBc均阴性。实验结果表明:1)乙肝疫苗能阻断树鼩感染HBV,进一步确证树鼩能感染HBV,是用于研究HBV的有用的动物模型;2)树鼩可能代替黑猩猩进行乙肝疫苗安全性和免疫保护效果鉴定之用。

关键词： 麻风杆菌   树Qu   动物模型  

摘要： 树鼩(Tupaia Belangeri)是云南的一种野生动物,属哺乳动物,体温近于人类者(38℃左右)。寿命5～10年。因而我们选择此动物进行麻风杆菌动物模型的实验。从1983年开始,在5年中,进行多种方式和多次的重复足垫的接种,证实麻风杆菌已能在此动物中生长繁殖,其细菌量可达2.7×10~9,多于小白鼠足垫中者。足垫的组织病理变化也符合麻风的表现。所以我们认为根据以上实验结果,证实树鼩是麻风杆菌又一个新的模型。

关键词： Seasonal population abundance   Soil surface-inhabiting arthropods   Abiotic environmental variables   Tropical semi-arid savanna  

摘要： Seasonality of relative population abundance in different groups of soil-surface arthropods was investigated monthly by pit-fall traps during a 2-year period in the grassland and tree-planted areas of a tropical semi-arid savanna at Warangal (south India). Densities of most groups were lowest during summer and highest during the rainy season. They were less abundant during winter. Arthropods were recorded in higher numbers in tree-planted compared to grassland areas. Certain arthropods that were found only during part of the year were recorded for a longer period in tree-planted area. Formicidae Monomorium indicum Forel, Crematogaster sp. and Pachycondyla? tesserinoda (Emery), and Coleoptera, Pachycera sp. reached maximum densities in the rainy season and minimum numbers during winter and summer in the grassland area. However, these species had lower densities during the rainy season and reached maximum densities during winter and summer in the tree-planted area. The seasonal abundance of arthropods showed significant linear correlations with different abiotic environmental variables such as rainfall, soil moisture, organic matter, soil and air temperatures, soil pH, relative humidity at the soil surface, and potassium and phosporus of surface soil. Soil moisture and rainfall were generally the strongest correlates with densities, particularly in the grassland area.