We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS seq...We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS sequences showed slight nucleotide divergences between Enteromorpha linza and Enteromorpha prolifera.In contrast,multiple highly variable regions were found in the ITS region of Enteromorpha flexuosa.In general,there were more variable sites in the NTS region than in the ITS region in the three species.The variations in 5S rDNA NTS sequences indicated that the molecular diversity of Enteromorpha from the coast of Yantai is very high.However,a phylogenetic tree constructed using 5S rDNA NTS sequence data indicated that genetic differences were not directly related to geographical distribution.展开更多
Let {Tn } be a renewal process in R＋ representing the successive arrival times of some natural events. We studied this process by using a record process approach under the assumption that the interarrival times T,, =...Let {Tn } be a renewal process in R＋ representing the successive arrival times of some natural events. We studied this process by using a record process approach under the assumption that the interarrival times T,, = Tn, - Ta-1, n = 1, 2...are exponentially i.i.d （independent and identically distributed）. The goal is to test that the first observed events are sporadic events. For testing the hypothesis ＂sporadic＂ we used the non-parametric test based on the probability distribution of the statistic of the number of records N, among{Xx }k-1= where Xk = （ΔTk）-1. We showed that it is independent of the cumulative distribution of the observations and that it is exactly calculated for each n. We illustrated this statistic on a simulated trajectory and we compared it with descriptive smoothing methods. We studied an application to a data set as storms in France and US.展开更多
基金Supported by the National Key Technology Research and Development Program(No.2008BA49B01)the Key Innovation Program of Chinese Academy of Sciences(No.KZCX2-YW-209)
文摘We collected nine Enteromorpha specimens from the coast of Yantai and evaluated their diversity based on analyses of their ITS(internal transcribed spacer) and 5S rDNA NTS(non-transcribed spacer) sequences.The ITS sequences showed slight nucleotide divergences between Enteromorpha linza and Enteromorpha prolifera.In contrast,multiple highly variable regions were found in the ITS region of Enteromorpha flexuosa.In general,there were more variable sites in the NTS region than in the ITS region in the three species.The variations in 5S rDNA NTS sequences indicated that the molecular diversity of Enteromorpha from the coast of Yantai is very high.However,a phylogenetic tree constructed using 5S rDNA NTS sequence data indicated that genetic differences were not directly related to geographical distribution.
文摘Let {Tn } be a renewal process in R＋ representing the successive arrival times of some natural events. We studied this process by using a record process approach under the assumption that the interarrival times T,, = Tn, - Ta-1, n = 1, 2...are exponentially i.i.d （independent and identically distributed）. The goal is to test that the first observed events are sporadic events. For testing the hypothesis ＂sporadic＂ we used the non-parametric test based on the probability distribution of the statistic of the number of records N, among{Xx }k-1= where Xk = （ΔTk）-1. We showed that it is independent of the cumulative distribution of the observations and that it is exactly calculated for each n. We illustrated this statistic on a simulated trajectory and we compared it with descriptive smoothing methods. We studied an application to a data set as storms in France and US.
