On Valuation Rings as Homomorphic Images of Valuation Domains.

A number of years ago, I. Kaplansky raised informally the question of whether every valuation ring could be expressed as a homomorphic image of a valuation domain. By a valuation ring, we mean a commutative ring with identity whose ideals are linearly ordered by inclusion. The classical notion of a valuation ring included the assumption that the ring is a domain. For two cases an affirmative answer to Kaplansky\u27s question is known: for 0-dimensional valuation rings; and, for valuation rings which are monoid rings. In the early 40\u27s, Kaplansky obtained structure theorems for a large class of (maximally complete) valuation domains. We approached his question with the idea of attempting to generalize his techniques in order to obtain anologous structure theorems for valuation rings. The hope was that, as a by-product, these theorems would yield the required valuation domain and homomorphism. In this paper are the results and questions which were discovered in the search for these structure theorems. In Chapter 1, several definitions (e.g., immediate extension, maximal completion, pseudo-convergent sequence) and results are extended from valuation domains to valuation rings and, when appropriate, more generally to quasi-local rings. In particular, it is shown that a valuation ring which is maximal is also maximally complete. In Chapter 2, after generalizing the concept of value group to that of value monoid, we define a long power series ring for such a monoid, with coefficients in a field, and prove such a ring is a homomorphic image of a valuation domain. In Chapter 3, we obtain a bound on the cardinality of a valuation ring which depends only on the cardinalities of the residue field and value monoid, then show every valuation ring has a maximal completion. Kaplansky\u27s work on maximally complete valuation domains (valued fields) is outlined in Chapter 4. A discussion of what had been hoped for and remarks on several unanswered questions, along with miscellaneous results, conclude Chapter 4

An introduction to Graph Data Management

A graph database is a database where the data structures for the schema and/or instances are modeled as a (labeled)(directed) graph or generalizations of it, and where querying is expressed by graph-oriented operations and type constructors. In this article we present the basic notions of graph databases, give an historical overview of its main development, and study the main current systems that implement them

Streptococcus iniae M-Like Protein Contributes to Virulence in Fish and Is a Target for Live Attenuated Vaccine Development

Streptococcus iniae is a significant pathogen in finfish aquaculture, though knowledge of virulence determinants is lacking. Through pyrosequencing of the S. iniae genome we have identified two gene homologues to classical surface-anchored streptococcal virulence factors: M-like protein (simA) and C5a peptidase (scpI).S. iniae possesses a Mga-like locus containing simA and a divergently transcribed putative mga-like regulatory gene, mgx. In contrast to the Mga locus of group A Streptococcus (GAS, S. pyogenes), scpI is located distally in the chromosome. Comparative sequence analysis of the Mgx locus revealed only one significant variant, a strain with an insertion frameshift mutation in simA and a deletion mutation in a region downstream of mgx, generating an ORF which may encode a second putative mga-like gene, mgx2. Allelic exchange mutagenesis of simA and scpI was employed to investigate the potential role of these genes in S. iniae virulence. Our hybrid striped bass (HSB) and zebrafish models of infection revealed that M-like protein contributes significantly to S. iniae pathogenesis whereas C5a peptidase-like protein does not. Further, in vitro cell-based analyses indicate that SiMA, like other M family proteins, contributes to cellular adherence and invasion and provides resistance to phagocytic killing. Attenuation in our virulence models was also observed in the S. iniae isolate possessing a natural simA mutation. Vaccination of HSB with the Delta simA mutant provided 100% protection against subsequent challenge with a lethal dose of wild-type (WT) S. iniae after 1,400 degree days, and shows promise as a target for live attenuated vaccine development.Analysis of M-like protein and C5a peptidase through allelic replacement revealed that M-like protein plays a significant role in S. iniae virulence, and the Mga-like locus, which may regulate expression of this gene, has an unusual arrangement. The M-like protein mutant created in this research holds promise as live-attenuated vaccine

Employee Reviews on Company Independent Sites and its Impact on Organizational Attractiveness: Role of Information Realism, Person – Environment Fit and Source Credibility Framework

Extant literature on recruitment has focused on the traditional sources of recruitment like company brochures, career fairs, and impact of such sources on intent to join the organization, productivity and turnover intention. The influence of recruitment related information on pre hire outcomes is still scarce and inconclusive. With the advent of technology and access to Internet, company websites have become an important source of recruitment. Apart from company websites, job seekers are now using company independent websites, forums or online communities to gather a more truthful picture and information about the job and organizational attributes. Social media too has become increasingly important medium where the current employees’ share how it is to work with the organization However research on web based recruitment is limited to company websites. Despite the widespread growth and practical use of these new and innovative media very little is known about how these independent sites influence recruitment pre hire outcomes. In this direction the proposed study presents a conceptual framework about how job seekers perceive company independent websites as a tool for providing recruitment communication and their impact on organizational attractiveness using Information Realism, Person-Environment fit framework, Source Credibility framework

Board monitoring and earnings management: do outside directors influence abnormal accruals?

This paper examines whether the incidence of earnings management by UK firms depends on board monitoring. We focus on two aspects of board monitoring: the role of outside board members and the audit committee. Results indicate that the likelihood of managers making income-increasing abnormal accruals to avoid reporting losses and earnings reductions is negatively related to the proportion of outsiders on the board. We also find that the chance of abnormal accruals being large enough to turn a loss into a profit or to ensure that profit does not decline is significantly lower for firms with a high proportion of outside board members. In contrast, we find little evidence that outside directors influence income-decreasing abnormal accruals when pre-managed earnings are high. We find no evidence that the presence of an audit committee directly affects the extent of income-increasing manipulations to meet or exceed these thresholds. Neither do audit committees appear to have a direct effect on the degree of downward manipulation, when pre-managed earnings exceed thresholds by a large margin. Our findings suggest that boards contribute towards the integrity of financial statements, as predicted by agency theory