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1.
讨论了非连通图C12(r1,0,r2,0,…,r6,0)∪Fk,4的优美性,证明了a,k,ri(i=1,2,…,6),为任意自然数,且当r5=r6=0, k=3,r6=a,r5≥2-a,k=4;r6≥4,k=5时,非连通图C12(r1,0,r2,0,…,r6,0)∪Fk,4是交错图。其中C12(r1,0,r2,0,…,r6,0)∪Fk,4表示圈C12的(r1,0,r2,0,…,r6,0)-冠,把顺序有一个公共点的k个C4的连通并图记作Fk,4。  相似文献   

2.
讨论了非连通图C4m-1∪C12m-8 ∪G的优美性,证明了当m为任意正整数,G是特征为k且缺k+6m-3标号值的交错图(6m-3≤k+6m-3≤| E(G)|)时,非连通图C4m-1∪ C12m-8∪G存在缺标号值k+1的优美标号,其中,G是具有m个顶点的圈.  相似文献   

3.
讨论了非连通图C4m-1∪C12m-8∪G的优美性,证明了当m为任意正整数,G是特征为k且缺标号值k+6m-4的交错图(6m-4≤k+6m-4≤|E(G)|)时,非连通图C4m-1∪C12m-8∪G存在缺标号值k+16m-9的优美标号,其中,Cm是具有m个顶点的圈.  相似文献   

4.
研究非连通图3C8m∪C8m-1∪G的优美性.证明如下结论:对任意正整数m,若图G是特征为k且缺标号值k+24m-2的交错图,则非连通图3C8m∪C8m-1∪G存在缺标号值k+1的优美标号.  相似文献   

5.
讨论非连通图C8(r1,0,r2,0,…,0)∪G的优美性,证明当r1,r2为任意自然数、G是特征为k且缺k+3标号值的交错图(3≤k+3|E(G)|)时,非连通图C8(r1,0,r2,0,…,0)∪G存在缺标号值k+1的特征为k+5的交错标号,其中C8是具有8个顶点的圈,C8(r1,0,r2,0,…,0)是圈C8的(r1,0,r2,0,…,0)-冠.  相似文献   

6.
讨论了非连通图C11(r1,0,r2,0,r3,0,…,0)∪G的优美性,给出了非连通图C11(r1,0,r2,0,r3,0,…,0)∪G是优美图的一个充分条件.  相似文献   

7.
讨论非连通图(P1∨Pm)∪C4n∪P2的优美性.证明如下结论:设m、n为任意正整数,当m≥2,1≤n≤2m-2时,非连通图(P1∨Pm)∪C4n∪P2是优美图,其中Pn是n个顶点的路,G1∨G2是图G1与G2的联图,C4n是4n个顶点的圈.  相似文献   

8.
讨论了非连通图C_(12)(r_1,0,r_2,0,r_3,0,…,0)∪G的优美性,给出了非连通图C_(12)(r_1,0,r_2,0,r_3,0,…,0)∪G是优美图的一个充分条件。  相似文献   

9.
讨论了非连通图C16(r1,0,r2,0,…,r8,0)∪Fk,4的优美性,证明了a,k,ri(i=1,2,…,8)为任意自然数,且当r6=r7=r8=0,k=4;r7+r8=2,k=5;r8=a,r7≥4-a,k=6;r8≥6,k=7时,非连通图C16(r1,0,r2,0,…,r8,0)∪Fk,4是交错图。  相似文献   

10.
非连通图C4m∪G 的优美标号   总被引:1,自引:0,他引:1  
讨论了非连通图C4 m∪G的优美性,给出了非连通图C4 m∪G是优美图的4个充分条件:当图G是缺标号值k+3 m且特征为k的交错图时,非连通图C4 m∪G存在着缺标号值k+1的优美标号;当图G是缺标号值k+m+1且特征为k的交错图时,非连通图C4 m∪G存在特征为2 m+k+1缺标号值k+1的交错标号;当图G是缺标号值k+2 m且特征为k的交错图时,非连通图C4 m∪G存在缺标号值k+3 m的优美标号;当图G是缺标号值k+2 m+1且特征为k的交错图时,非连通图C4 m∪G存在缺标号值k+m的优美标号。  相似文献   

11.
本文讨论了任意形状蛇形图的消圈数,给出每节都是4-圈情形的蛇形图别名函数C(H),并证明每节为4-圈的蛇形图的消圈数等于它的别名函数的势.另外,在保持消圈数不变的情况下,通过简单的收缩、剖分运算把求解任意情形的蛇形图的消圈数问题归为求解每节都是4-圈特殊情形下的蛇形图消圈数问题.  相似文献   

12.
为初步了解上海市场蛇寄生虫的感染情况,剖检了来自上海市场罚没的2种19条蛇,其中赤链蛇(Dinodon rufozonatum)9条、大王蛇(Elaphe carinata)10条,分别取血液涂片,依序检查体表、皮下、肌肉、心脏、肺脏、肝脏、胃、肠道等组织器官,收集检获的寄生虫,显微镜初步观察.结果显示:在19条蛇均未检出外体寄生虫、吸虫和棘头虫,在皮下和体内检出线虫和绦虫,在血液中检出肝簇虫(Hepatozoon),蛇的寄生虫感染率为100%.线虫、绦虫、肝簇虫在赤链蛇的检出率分别为77.88%、100%、0,在大王蛇的检出率全部为100%.从19条蛇共检获线虫192条、绦虫(裂头蚴)1236条,其中69.79%的线虫和86.55%的绦虫来自大王蛇.按检出的脏器统计,93.20%的绦虫来自皮下与肌肉,65.63%的线虫来自胃.调查结果表明,上海市场两种蛇的寄生虫感染率高、感染强度大,其中检出的裂头蚴为人畜共患寄生虫,吃蛇皮与蛇肉、吞蛇胆存在感染寄生虫的极大风险.因此,保护蛇类等野生动物,也是保护人类自身.  相似文献   

13.
利用对称动态轮廓模型自动检测图像最优镶嵌线   总被引:6,自引:0,他引:6  
提出利用对称动态轮廓模型方法自动检测多景影像的最优镶嵌线。该方法将影像间色彩相似性和纹理相似性、公式化为动态轮廓线的能量函数。利用这种方法能够自动找到一条影像表面色调和纹理差异更小的镶嵌线,在轮廓线的选取和迭代过程中,结合了影像亮度和纹理差异的信息,检测出的镶嵌线优于仅用影像的梯度信息检测出的镶嵌线。研究以两景相邻影像自动寻找镶嵌线为例进行了实验,取得了良好的效果。  相似文献   

14.
测定六种分布于浙江的游蛇属蛇类的体长和尾长,检测尾长的两性异形和种间差异.六种游蛇属蛇的两性个体尾长均与体长呈显著的正相关,六种游蛇属蛇间体长差异显著.协方差分析显示渔游蛇、草游蛇、虎斑游蛇的雄性的尾长显著大于雌性,水赤链游蛇、锈链游蛇、乌游蛇的尾长无显著的两性差异.种间相对尾长的差异显著.  相似文献   

15.
了解贵州省野生青蛙和蛇类自然感染曼氏裂头蚴的情况。方法:从我省贵阳、安顺、惠水、织金及水城5个地区捕捉野生青蛙和蛇,进行解剖检查和镜下鉴定曼氏裂头蚴,并对数据进行分析。结果:贵州省野生青蛙裂头蚴的自然感染率为18.04%(882/4 888),感染强度为1~41条;野生蛇类的自然感染率为24.04%(25/104),感染强度为1~212条,其中,以乌梢蛇和王锦蛇的感染率较高。结论:蛙、蛇体内裂头蚴感染率高,与我省裂头蚴病不断发生密切相关。因此,加强健康教育,改变不良的生活方式和饮食习俗,保护野生蛙和蛇对预防裂头蚴病是十分重要的。  相似文献   

16.
Apesteguía S  Zaher H 《Nature》2006,440(7087):1037-1040
It has commonly been thought that snakes underwent progressive loss of their limbs by gradual diminution of their use. However, recent developmental and palaeontological discoveries suggest a more complex scenario of limb reduction, still poorly documented in the fossil record. Here we report a fossil snake with a sacrum supporting a pelvic girdle and robust, functional legs outside the ribcage. The new fossil, from the Upper Cretaceous period of Patagonia, fills an important gap in the evolutionary progression towards limblessness because other known fossil snakes with developed hindlimbs, the marine Haasiophis, Pachyrhachis and Eupodophis, lack a sacral region. Phylogenetic analysis shows that the new fossil is the most primitive (basal) snake known and that all other limbed fossil snakes are closer to the more advanced macrostomatan snakes, a group including boas, pythons and colubroids. The new fossil retains several features associated with a subterranean or surface dwelling life that are also present in primitive extant snake lineages, supporting the hypothesis of a terrestrial rather than marine origin of snakes.  相似文献   

17.
甘肃蛇类研究   总被引:2,自引:0,他引:2  
作者通过调查及文献整理,甘肃省蛇类有38种与亚种,隶21属4科,对其组成,区系作了分析,资源作了评价。  相似文献   

18.
Many advanced snakes use fangs-specialized teeth associated with a venom gland-to introduce venom into prey or attacker. Various front- and rear-fanged groups are recognized, according to whether their fangs are positioned anterior (for example cobras and vipers) or posterior (for example grass snakes) in the upper jaw. A fundamental controversy in snake evolution is whether or not front and rear fangs share the same evolutionary and developmental origin. Resolving this controversy could identify a major evolutionary transition underlying the massive radiation of advanced snakes, and the associated developmental events. Here we examine this issue by visualizing the tooth-forming epithelium in the upper jaw of 96 snake embryos, covering eight species. We use the sonic hedgehog gene as a marker, and three-dimensionally reconstruct the development in 41 of the embryos. We show that front fangs develop from the posterior end of the upper jaw, and are strikingly similar in morphogenesis to rear fangs. This is consistent with their being homologous. In front-fanged snakes, the anterior part of the upper jaw lacks sonic hedgehog expression, and ontogenetic allometry displaces the fang from its posterior developmental origin to its adult front position-consistent with an ancestral posterior position of the front fang. In rear-fanged snakes, the fangs develop from an independent posterior dental lamina and retain their posterior position. In light of our findings, we put forward a new model for the evolution of snake fangs: a posterior subregion of the tooth-forming epithelium became developmentally uncoupled from the remaining dentition, which allowed the posterior teeth to evolve independently and in close association with the venom gland, becoming highly modified in different lineages. This developmental event could have facilitated the massive radiation of advanced snakes in the Cenozoic era, resulting in the spectacular diversity of snakes seen today.  相似文献   

19.
20.
李勇军 《科技信息》2010,(17):J0368-J0368,J0082
蛇的全身都是宝,利用价值极高,武夷山是蛇的王国,蛇类产品的开发利用走在全国的前列。要保护好蛇类,才能可持续利用。  相似文献   

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