15,311 research outputs found

    Isolation of a Novel Phage OTooleKemple52

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    A bacteriophage is a virus capable of infecting bacteria like ubiquitous soil-dwelling genus Bacillus. Within the Bacillus genus, there is the “ACT family” made up of B. thuringiensis, B. cereus, and B. anthracis, which are highly related but with different pathogenic characteristics. Because of this, phages isolated using a species in this group may have a broad host range encompassing several species from Bacillus. Since B. cereus and B. anthracis can result in fatal to mild sickness in humans, the non-pahtogenic B. thuringiensis kurstaki was used to discover and characterize novel phages. The phage OTooleKemple52 was isolated from a soil sample collected from Chesapeake, VA using “soil enrichment” to increase phage concentration and thus make detection more likely. A phage plaque was observed from this enrichment infection upon plating. The phage population was then purified until the morphology of the phage plaques was consistent (3 mm diameter with pinpoint clear centers). A large volume of phage stock (high titer lysate, HTL) was collected and was then used to obtain purified DNA for gel electrophoresis and genome sequencing. Additionally, an HTL sample was stained with 1% uranyl acetate and imaged using transmission electron microscopy to determine a myoviridae morphology with a head diameter of 80 nm and a tail length of 200 nm. The phage has a broad host range and was able to able to form plaques on 6 out of 8 Bacillus strains tested. The genome of the phage will be annotated and compared to other phage genomes. Through studying phages we can work to better understand both phage diversity and the interrelatedness of the Bacillus genus. The benefits of studying bacteriophages have reaches from environmental to medical significance because of the ubiquitous and pathogenic characteristics of the host bacteria.https://scholarscompass.vcu.edu/uresposters/1241/thumbnail.jp

    Hydrodynamics of Monolayer Domains at the Air-Water Interface

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    Molecules at the air-water interface often form inhomogeneous layers in which domains of different densities are separated by sharp interfaces. Complex interfacial pattern formation may occur through the competition of short- and long-range forces acting within the monolayer. The overdamped hydrodynamics of such interfacial motion is treated here in a general manner that accounts for dissipation both within the monolayer and in the subfluid. Previous results on the linear stability of interfaces are recovered and extended, and a formulation applicable to the nonlinear regime is developed. A simplified dynamical law valid when dissipation in the monolayer itself is negligible is also proposed. Throughout the analysis, special attention is paid to the dependence of the dynamical behavior on a characteristic length scale set by the ratio of the viscosities in the monolayer and in the subphase.Comment: 12 pages, RevTeX, 4 ps figures, accepted in Physics of Fluids

    Composite CDMA - A statistical mechanics analysis

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    Code Division Multiple Access (CDMA) in which the spreading code assignment to users contains a random element has recently become a cornerstone of CDMA research. The random element in the construction is particular attractive as it provides robustness and flexibility in utilising multi-access channels, whilst not making significant sacrifices in terms of transmission power. Random codes are generated from some ensemble, here we consider the possibility of combining two standard paradigms, sparsely and densely spread codes, in a single composite code ensemble. The composite code analysis includes a replica symmetric calculation of performance in the large system limit, and investigation of finite systems through a composite belief propagation algorithm. A variety of codes are examined with a focus on the high multi-access interference regime. In both the large size limit and finite systems we demonstrate scenarios in which the composite code has typical performance exceeding sparse and dense codes at equivalent signal to noise ratio.Comment: 23 pages, 11 figures, Sigma Phi 2008 conference submission - submitted to J.Stat.Mec

    Waiting For The Moon And You

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    https://digitalcommons.library.umaine.edu/mmb-vp/5059/thumbnail.jp

    Black Stem Rust and the Common Barberry in South Dakota

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    Stem rust is one of the most dreaded as well as the most destructive diseases of the small-grain crop of South Dakota and the entire spring-wheat area. This rust attacks wheat, oats, barley, rye and about 6 0 cultivated and wild grasses. (See more in Text)

    Studies on the Epidemiology of Stem Rust in South Dakota

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    The economic importance and general distribution of stem rust (Puccinia graminis) has warranted unlimited study and discussion of this plant disease among scientific and practical grain growers. Most of the study has been on the life cycle of stem rust in order to suggest control measures. Some workers express considerable importance on the heterocism of the fungus, thus favoring the elimination of the alternate hosts, which are universally adopted as species of the Berberis and related genera. Others recognize the importance of the alternate hosts, but do not believe in their indispensability. Since the campaign for the eradication of rust-susceptible species of Berberis was started in the thirteen north-central, wheat-growing states, this phase of the problem has received considerable attention among scientific workers. The importance of stem rust in South Dakota is well known. IN certain years ravaging epidemics have taken a toll of small-grain groups estimated at over $65,000,000. Practically every year, local or regional epidemics occur which cause some damage. With these facts in mind, a study of the epidemiology of stem rust in this State was undertaken with special reference to: (1) the overwintering of urediniospores, (2) the importance of in-blown spores, and (3) the incubation period of urediniospores. [Introduction -- Page 4
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