Consistency in Regularizations of the Gauged NJL Model at One Loop Level

In this work we revisit questions recently raised in the literature associated to relevant but divergent amplitudes in the gauged NJL model. The questions raised involve ambiguities and symmetry violations which concern the model's predictive power at one loop level. Our study shows by means of an alternative prescription to handle divergent amplitudes, that it is possible to obtain unambiguous and symmetry preserving amplitudes. The procedure adopted makes use solely of {\it general} properties of an eventual regulator, thus avoiding an explicit form. We find, after a thorough analysis of the problem that there are well established conditions to be fulfiled by any consistent regularization prescription in order to avoid the problems of concern at one loop level.Comment: 22 pages, no figures, LaTeX, to appear in Phys.Rev.

Distributed database management systems : Architectural design choices for the cloud

Cloud computing has changed the way we used to exploit software and systems. The two decades’ practice of architecting solutions and services over the Internet has just revolved within the past few years. End users are now relying more on paying for what they use instead of purchasing a full-phase license. System owners are also in rapid hunt for business profits by deploying their services in the Cloud and thus maximising global outreach and minimising overall management costs. However, deploying and scaling Cloud applications regionally and globally are highly challenging. In this context, distributed data management systems in the Cloud promise rapid elasticity and horizontal scalability so that Cloud applications can sustain enormous growth in data volume, velocity, and value. Besides, distributed data replication and rapid partitioning are the two fundamental hammers to nail down these challenges. While replication ensures database read scalability and georeachability, data partitioning favours database write scalability and system-level load balance. System architects and administrators often face difficulties in managing a multi-tenant distributed database system in Cloud scale as the underlying workload characteristics change frequently. In this chapter, the inherent challenges of such phenomena are discussed in detail alongside their historical backgrounds. Finally, potential way outs to overcome such architectural barriers are presented under the light of recent research and development in this area

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution.

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists