Evolution of the Internet AS-level topology:From nodes and edges to components

Studying the topology of infrastructure communication networks(e.g., the Internet) has become a means to understand and develop complex systems. Therefore, investigating the evolution of Internet network topology might elucidate disciplines governing the dynamic process of complex systems. It may also contribute to a more intelligent communication network framework based on its autonomous behavior. In this paper, the Internet Autonomous Systems(ASes) topology from 1998 to 2013 was studied by deconstructing and analysing topological entities on three different scales(i.e., nodes,edges and 3 network components: single-edge component M1, binary component M2 and triangle component M3). The results indicate that: a) 95% of the Internet edges are internal edges(as opposed to external and boundary edges); b) the Internet network consists mainly of internal components, particularly M2 internal components; c) in most cases, a node initially connects with multiple nodes to form an M2 component to take part in the network; d) the Internet network evolves to lower entropy. Furthermore, we find that, as a complex system, the evolution of the Internet exhibits a behavioral series,which is similar to the biological phenomena concerned with the study on metabolism and replication. To the best of our knowledge, this is the first study of the evolution of the Internet network through analysis of dynamic features of its nodes,edges and components, and therefore our study represents an innovative approach to the subject.

BIK1 cooperates with BAK1 to regulate constitutive immunity and cell death in Arabidopsiss

Summary In Arabidopsis, both the membrane-anchored receptor-like kinase （RLK） BAK1 and the receptor-like cytoplasmic kinase （RLCK） BIK1 are important mediators of transmembrane signal transduction that regulate plant development and immunity. However, little attention has been paid to their genetic association. This study found the bak1 bik1 double mutant of Arabidopsis displayed a severe dwarfism phenotype due to constitutive immunity and cell death in developing plants. These data suggest that BIK1 cooperates with BAK1 to regulate constitutive immunity and cell death.

The juxtamembrane domains of Arabidopsis CERK1,BAK1,and FLS2 play a conserved role in chitin-induced signaling

Arabidopsis thallana CERK1 is an essential receptor-like kinase in the chitin signal transduction pathway. The juxtamembrane (JM) domain of CERK1 regulates the kinase activity of this receptor. Here we demonstrate that the JM domains of LysM RLKs, CERK1,and OsCERK1 play a functionally conserved role in the activation of chitin signaling in Arabidopsis. The Ctrmini of the JM domains of both CERK1 and OsCERK1 are indispensable for their function. Moreover, after replacing the JM domain of CERK1 with that of the non-homologous RLK, BAK1 (CJBa) or FL52 (CJFI), the chimeric CERK1 receptors maintained their ability to ac.tivate chitin signaling in Arabidopsis. Interestingly, theheterologous expression of CJBa and CJFI did not induce cell death in Nicotiand benthamiand leaves. These results suggest that the JM domains of CERK1, BAK1, and FLS2 play a conserved role in chitin signaling via a mechanism not related to sequence homology.

Scheduling algorithms for time-constrained big-le transfers in the Internet of Vehicles

In order to transfer large les and provide high-quality services in the IoV(Internet of Vehicles),intelligent routing and scheduling are indispensable for fast transfers and effcient network utilization,particularly when multi-path routing is allowed in the wired-transfer.Thus,a network administrator must select a set of feasible paths over which the transfer can be conducted.We consider a TBTS(Time-constrained Big-le Transfer Scheduling)problem in this paper.We prove that TBTS problem is NP-hard and that the TBTS problem can be solved by addressing a corresponding maximum ow over time problem with multi-path routing technique.We then propose both a heuristic algorithm(TBTS-H)and an exact algorithm(TBTS-A)to solve the TBTS problem.Although both of the proposed approaches can solve the TBTS problem,the heuristic runs more effciently by trading accuracy for delay,while the exact algorithm can achieve high accuracy for delay,at the cost of increased running-time.The corresponding simulation results illustrate this trade-o.Additionally,we conduct some comparisons between our proposed approaches and a traditional single-path routing scheme.

Ferredoxin：Thioredoxin Reductase Is Required for Proper Chloroplast Development and Is Involved in the Regulation of Plastid Gene Expression in Arabidopsis thaliana

Dear Editor, In oxygenic photosynthetic organisms, carbon metabolism is regulated in a light-dependent manner by a distinctive ferredoxin/thioredoxin （Fd/TRX） redox sys- tem, in which Fd：TRX reductase （FTR） acts as the central redox transmitter to catalyze the reduction of TRX, with photosynthetic electrons coming from Fd （Schurmann and Buchanan, 2008; Dietz and Pfannschmidt, 2011）. Recently, there is increasing evidence to suggest the diverse functions of TRX in chloroplast development, which requires light- induced transcription and translation of nuclear and plas- tid genes, biosynthesis of lipids and pigments, assembly of photosynthetic pigment-protein complexes, etc.