In this paper we describe a Sequential Importance Sampling (SIS) procedure for counting the number of vertex covers in general graphs. The optimal SIS proposal distribution is the uniform over a suitably restricted set, but is not implementable. We will consider two proposal distributions as approximations to the optimal. Both proposals are based on randomization techniques. The first randomiza...

Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces (S.) and in particular, the most highly represented species was ...

Streptomyces sp. H-KF8 is an actinobacterial strain isolated from marine sediments of a Chilean Patagonian fjord. Morphological characterization together with antibacterial activity was assessed in various culture media, revealing a carbon-source dependent activity mainly against Gram-positive bacteria (S. aureus and L. monocytogenes). Genome mining of this antibacterial-producing bacterium rev...

Streptomycetes differ from other prokaryotic organisms in their mycelial life cycle and in possessing a large, linear, GC-rich chromosome. To deduce structural features of the Streptomyces origin of chromosomal replication, the oriC sequences of three Streptomyces species (S. antibioticus, S. chrysomallus and S. lividans) were compared. In Streptomyces, the oriC region contains 19 DnaA boxes wh...

Streptomycetes group was studied in twenty-three soil samples of western region. The highest density of this group was found in 3 soil samples collected from AI-Madinah Al-Munawwarah. Six Streptomyces series were observed. Gray series represented the most dominant isolates. The highest antimicrobial activity was recorded in the case of gray and red series. Streptomyces MR13 (red series) had a b...

Although recent molecular techniques have greatly expanded our knowledge of microbial biogeography, the functional biogeography of soil microorganisms remains poorly understood. In this work, we explore geographic variation in Streptomyces phenotypes that are critical to species interactions. Specifically, we characterize Streptomyces from different locations from multiple continents for antibi...

For most Global Positioning System (GPS) standard positioning service (SPS) users, real-time satellite orbits and clocks are derived from predicted ephemeris and clock parameters in broadcast navigation messages. Broadcast ephemeris and clock errors, the differences between the broadcast orbits/clocks and the truth, account for a dominant portion of signal-in-space (SIS) errors. Traditionally, ...