A sheep pangenome reveals the spectrum of structural variations and their effects on tail phenotypes

Structural variations (SVs) are a major contributor to genetic diversity and phenotypic variations, but their prevalence and functions in domestic animals are largely unexplored. Here we generated high-quality genome assemblies for 15 individuals from genetically diverse sheep breeds using Pacific Biosciences (PacBio) high-fidelity sequencing, discovering 130.3 Mb nonreference sequences, from which 588 genes were annotated. A total of 149,158 biallelic insertions/deletions, 6531 divergent alleles, and 14,707 multiallelic variations with precise breakpoints were discovered. The SV spectrum is characterized by an excess of derived insertions compared to deletions (94,422 vs. 33,571), suggesting recent active LINE expansions in sheep. Nearly half of the SVs display low to moderate linkage disequilibrium with surrounding single-nucleotide polymorphisms (SNPs) and most SVs cannot be tagged by SNP probes from the widely used ovine 50K SNP chip. We identified 865 population-stratified SVs including 122 SVs possibly derived in the domestication process among 690 individuals from sheep breeds worldwide. A novel 168-bp insertion in the 5' untranslated region (5' UTR) of HOXB13 is found at high frequency in long-tailed sheep. Further genome-wide association study and gene expression analyses suggest that this mutation is causative for the long-tail trait. In summary, we have developed a panel of high-quality de novo assemblies and present a catalog of structural variations in sheep. Our data capture abundant candidate functional variations that were previously unexplored and provide a fundamental resource for understanding trait biology in sheep

A Fast and Robust Content-based Publish/Subscribe Architecture

We present cluster-based publish/subscribe, a novel architecture that is not only resilient to event broker failures but also provides load balancing and fast event dissemination service. Our proposed approach achieves fault tolerance by organizing event brokers in clusters. Multiple intercluster links provide continuous availability of dissemination service in presence of broker failure without requiring subscription retransmission or reconstruction of broker overlay. Furthermore, the proposed architecture provides a fast event dissemination infrastructure that significantly reduces subscription and publication dissemination traffic and load on event brokers. Our experimental results show that even in the presence of 10 % failure rate in broker network, event dissemination is not interrupted and dissemination speed and load are not affected significantly.

Sama: A Scalable Group Communication Mechanism for Mobile Agents

Abstract. Provision of fast and scalable group communication for mobile agents can considerably improve their efficiency. Unfortunately, most of the existing approaches do not scale well when the number of agents grows. In this paper, we propose Sama, a new group communication mechanism, to speed up message delivery to a group of mobile agents. The main contribution of Sama is distribution and parallelization of message propagation in an efficient way to achieve scalability and speed up message delivery to the group members. Sama uses Message Dispatcher Objects (MDOs), which are stationary agents on each host, to propagate messages in a parallel manner. The proposed mechanism is independent of agent locations and transparently delivers messages to the group using a constant number of remote messages. Experimental results show that message delivery time is significantly reduced in Sama compared to the previously proposed methods

Subscription Subsumption Evaluation for Content-Based Publish/Subscribe Systems

Abstract. In this paper we address the problem of subsumption checking for subscriptions in pub/sub systems. We develop a novel approach based on negative space representation for subsumption checking and provide efficient algorithms for subscription forwarding in a dynamic pub/ sub environment. We then provide heuristics for approximate subsumption checking that greatly enhance the performance without compromising the correct execution of the system and only adding incremental cost in terms of extra computation in brokers. We illustrate the advantages of this novel approach by carrying out extensive experimentation. Keywords: Publish/Subscribe, Subscription Subsumption, Messageoriented middleware.

CloudDB: One Size Fits All Revived

We are witnessing the emergence of Cloud Computing as a promising step in the evolution of information technology to address the challenges many organizations are facing in today’s fast paced and fiercely competitive economic environment [1]. I