Complex atrial tachycardia with alternating cycle length:What is the mechanism?

Background Atrial tachycardia(AT)with cycle length(CL)alternans is uncommon and conventional mapping of this AT remains challenging. We used an ultrahigh density mapping system to rapidly map complicated circuits with sufficient spatial resolution and electrogram quality to elucidate the precise mechanism of this special ATs. Methods Of 210 consecutive patients with clinical ATs who underwent catheter ablation with the ultrahigh density mapping system,4 patients(1.9%)with CL alternans were identified. The AT alternating cycles mapped by the Rhythmia mapping system for long CL were 317±51(range 245-355)ms and for short CL were 282±51(range 235-333)ms. Both long and short cycles followed in 1∶1 sequence in all 4 patients(longshort-long-short). Results By comparing the separate maps with long and short CL,we classified ATs with CL alternans into 2 types. In type 1,CL alternans resulted from an intermittent 2∶1 conduction block through the slow conduction channel in the small circuit. In type 2,CL alternans caused by the alternated conduction velocity passing through the conduction gap were manifested. Ablation at the fractionated potentials contributes to the termination of AT in 3 of the 4 patients. Conclusions Ultrahigh density mapping system can accurately identify the mechanism of complex ATs with alternating CL. The CL alternans may be related to the intermittent conduction block within the channel of the small circuitor different conduction velocity through the identical channel. Fractionated electrogram recorded in the common isthmus or some"conduction gaps"may be a reasonable approach to terminate these ATs.

A Relationship between Solar Activity and Frequency of Natural Disasters in China

The relationship between the length of the solar cycle, a good indicator of long-term change in solar activity, and natural disasters (drought, flood, and strong earthquakes) in China during the last 108 yearsis analyzed. The results suggest that the length of solar cycle may be a useful indicator for drought/flood and strong earthquakes. When the solar activity strengthens, we see the length of the solar cycle shorten and more floods occur in South China and frequent strong earthquakes happen in the Tibetan Plateau, but the droughts in East China as well as the strong earthquakes in Taiwan and at the western boundary of China are very few. The opposite frequencies occur when the solar activity weakens. The current study indicates that the solar activity may play an important role in the climate extremes and behavior in the lithosphere.

Accelerated recruitment of copepod Calanus hyperboreus in pelagic slope waters of the western Arctic Ocean

Shelf-basin advection is essential to subsistence of the Arctic copepod Calanus hyperboreus population in high basin area. Its abundance, population structure and body size in pelagic layer were investigated with samples collected over a large range in the western Arctic Ocean during summer 2003, to evaluate the geographical variation in recruitment pattern. Calanus hyperboreus was absent from the shallow areas of the Chukchi Sea and most abundant in the slope area between the Chukchi Sea and Chukchi Abyssal Plain（CS-slope）. Total abundance varied between 1 110.0 and 5 815.0 ind./m^2 in the CS-slope area and ranged from 40.0 to 950.0 ind./m^2 in the other areas. Early stages（CI–IV） dominated in the CS-slope area, whereas CV and adult females were frequently recorded only in deep basin areas. Geographical difference of prosome length was most evident in CIII,with average ranging from 2.48 to 2.61 mm at the CS-slope stations and 2.16–2.37 mm at the others. Abundance of early developmental stages（CI–CIV） correlated positively with Chl a concentration, but negative correlation was observed in late stages（CV–adult）. Our results indicated that C. hyperboreus can benefit from primary production increase through accelerated development in the first growth season and the productive CS-slope area is a potential source for slope-basin replenishment.

A Superior Sales Mode for a Two-Echelon Supply Chain of Perishable Products

This paper considers sales mode selection issues for a two-echelon supply chain of perishable products involving a supplier and a retailer.Consumers’purchase desire is assumed to be positive correlation with the freshness of the product.First,the traditional sales mode is examined,in which the supplier and the retailer play a Stackelberg game.We propose a three-layer decision model for this situation,and obtain dynamic pricing strategies and selling cycle length.It is shown that the retailer has little motivation to order many perishable products so as to avoid a long selling cycle length.Second,the commission-charge mode is analyzed,in which the retailer declares its decision first.In this mode,we demonstrate that the perishable product will be on sale during the whole shelf life under a certain condition.The correlation between the sales price of each stage and the remaining shelf-life length is analyzed.Third,the superiority analysis for the two sales modes is conducted.We show the relation between the selling cycle lengths of the two modes.By our analysis,it is shown that both the supplier and the retailer gain more profits when the commission-charge mode is adopted and the commission rate locates in a certain open interval.Finally,a numerical illustration is presented to visualize the discussed models,and some supplements are made for the acquired conclusions by the illustration.

偶图K_(n,n+7)-A(|A|≤3)的圈长分布唯一性(英文)

The cycle length distribution of a graph of order n is denoted by (c1,c2,...,cn), where ci is the number of cycles of length i. In this paper, we obtain that a graph G is uniquely determined by its cycle distribution if: (1) G = Kn,n+7 (n ≥ 10); or (2) G = Kn,n+7 - A (|A| = 1,n ≥ 12); or (3) G = Kn,n+7 - A (|A| = 2,n ≥ 14); or (4) G = Kn,n+7 - (|A| = 3,n ≥ 16), where A - E(Kn,n+7).

On behavior of two-dimensional cellular automata with an exceptional rule under periodic boundary condition

This article deals with the behavior of two-dimensional （2-D） cellular automata （CA） with a special rule under periodic boundary condition by using matrix algebra. The important characteristics of CA have been studied, such as Garden of Eden （GOE）, maximal transient length, maximal cycle length and so forth. Several necessary and sufficient conditions are provided, which guarantee a given configuration of being a GOE in different cases. Besides, algorithms are proposed to obtain the number of GOEs, the maximal transient length, and the maximal cycle length in such a CA with the rule mentioned above under periodic condition.

Vertex-Distinguishing E-Total Coloring of the Graphs mC_3 and mC_4

Let G be a simple graph. A total coloring f of G is called E-total-coloring if no two adjacent vertices of G receive the same color and no edge of G receives the same color as one of its endpoints. For E-total-coloring f of a graph G and any vertex u of G, let Cf （u） or C（u） denote the set of colors of vertex u and the edges incident to u. We call C（u） the color set of u. If C（u） ≠ C（v） for any two different vertices u and v of V（G）, then we say that f is a vertex-distinguishing E-total-coloring of G, or a VDET coloring of G for short. The minimum number of colors required for a VDET colorings of G is denoted by X^evt（G）, and it is called the VDET chromatic number of G. In this article, we will discuss vertex-distinguishing E-total colorings of the graphs mC3 and mC4.

Efficient Parallel Algorithms for Some Graph Theory Problems

In this paper,a sequential algorithm computing the all vertex pair distance matrix D and the path matrix Pis given.On a PRAM EREW model with p,1≤p≤n^2,processors,a parallel version of the sequential algorithm is shown.This method can also be used to get a parallel algorithm to compute transitive closure arrayof an undirected graph.The time complexify of the parallel algorithm is O(n^3/p).If D,P andare known,it is shown that the problems to find all connected components, to compute the diameter of an undirected graph,to determine the center of a directed graph and to search for a directed cycle with the minimum(maximum)length in a directed graph can all be solved in O(n^2/p^+ logp)time.