Learn More
Recently we described the isolation of spontaneous bacteriophage K139-resistant Vibrio cholerae O1 El Tor mutants. In this study, we identified phage-resistant isolates with intact O antigen but altered core oligosaccharide which were also affected in galactose catabolism; this strains have mutations in the galU gene. We inactivated another gal gene, galE,(More)
Since mobile commerce (m-commerce) started to be intensively discussed in the press, financial service companies are said to be the winners of m-commerce. But looking at existing m-commerce applications, you will find <i>really</i> interesting information only on few sites. In addition, there are many of these applications, which are just in a prototype(More)
Multimedia applications demand specific support from database management systems due to the characteristics of multimedia data and their interactive usage. This includes integrated support for high–volume and time–dependent (continuous) data types like audio and video. One critical issue is to provide handling of continuous data streams including buffer(More)
Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the(More)
Exogenous NAD utilization or pyridine nucleotide cycle metabolism is used by many bacteria to maintain NAD turnover and to limit energy-dependent de novo NAD synthesis. The genus Haemophilus includes several important pathogenic bacterial species that require NAD as an essential growth factor. The molecular mechanisms of NAD uptake and processing are(More)
Large multimedia document archives may hold a major fraction of their data in tertiary storage libraries for cost reasons. This paper develops an integrated approach to the vertical data migration between the tertiary, secondary, and primary storage in that it reconciles speculative prefetching, to mask the high latency of the tertiary storage, with the(More)
Large multimedia document archives hold most of their data in near-line tertiary storage libraries for cost reasons. This paper develops an integrated approach to the vertical data migration between the tertiary and secondary storage in that it reconciles speculative preloading, to mask the high latency of the tertiary storage, with the replacement policy(More)
Although today's computers provide huge amounts of main memory, the ever-increasing load of large data servers, imposed by resource-intensive decision-support queries and accesses to multimedia and other complex data, often leads to memory contention and may result in severe performance degradation. Therefore, careful tuning of memory mangement is crucial(More)
Workflow management systems (WFMSs) that are geared for the orchestration of enterprise-wide or even " virtual-enterprise "-style business processes across multiple organizations are complex distributed systems. They consist of multiple workflow engines, application servers, and ORB-style communication servers. Thus, deriving a suitable configuration of an(More)
Multimedia applications require continuous delivery of time-dependent data. In best-effort systems where no resource reservation is possible, adaptation strategies are necessary in case of high system load. We propose an adaptation framework for a client-pull architecture where continuous data are requested and buffered by the presenting client. The current(More)