3,899 research outputs found

    Genome Assembly Improvement and Mapping Convergently Evolved Skeletal Traits in Sticklebacks with Genotyping-by-Sequencing.

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    Marine populations of the threespine stickleback (Gasterosteus aculeatus) have repeatedly colonized and rapidly adapted to freshwater habitats, providing a powerful system to map the genetic architecture of evolved traits. Here, we developed and applied a binned genotyping-by-sequencing (GBS) method to build dense genome-wide linkage maps of sticklebacks using two large marine by freshwater F2 crosses of more than 350 fish each. The resulting linkage maps significantly improve the genome assembly by anchoring 78 new scaffolds to chromosomes, reorienting 40 scaffolds, and rearranging scaffolds in 4 locations. In the revised genome assembly, 94.6% of the assembly was anchored to a chromosome. To assess linkage map quality, we mapped quantitative trait loci (QTL) controlling lateral plate number, which mapped as expected to a 200-kb genomic region containing Ectodysplasin, as well as a chromosome 7 QTL overlapping a previously identified modifier QTL. Finally, we mapped eight QTL controlling convergently evolved reductions in gill raker length in the two crosses, which revealed that this classic adaptive trait has a surprisingly modular and nonparallel genetic basis

    Quantum wires from coupled InAs/GaAs strained quantum dots

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    The electronic structure of an infinite 1D array of vertically coupled InAs/GaAs strained quantum dots is calculated using an eight-band strain-dependent k-dot-p Hamiltonian. The coupled dots form a unique quantum wire structure in which the miniband widths and effective masses are controlled by the distance between the islands, d. The miniband structure is calculated as a function of d, and it is shown that for d>4 nm the miniband is narrower than the optical phonon energy, while the gap between the first and second minibands is greater than the optical phonon energy. This leads to decreased optical phonon scattering, providing improved quantum wire behavior at high temperatures. These miniband properties are also ideal for Bloch oscillation.Comment: 5 pages revtex, epsf, 8 postscript figure

    Neuronal Cell Model and Methods of Use Thereof

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    We previously described a novel in vitro model of a non-productive herpes simplex virus type 1 (HSV-1) infection in neurally-differentiated (ND)-PC12 cells that allows for inducible virus replication upon forskolin and heat stress (HS) treatment. In this research, we further characterized the model with respect to HSV-2 strain 333. We found that: (i) ND-PC12 cells are non-permissive to HSV-2 replication; (ii) HSV-2 can establish a quiescent infection, like HSV-1, in ND-PC12 cells with the transient use of acycloguanosine (ACV); however unlike HSV-1, anti-viral conditions are not obligatory to establish and maintain a quiescent state; (iii) the quiescent state is maintained in the presence of Vero cell cocultivation indicating that such cultures are free of infectious virus; and (iv) a high percentage of quiescently infected (QIF)-PC 12 cell cultures (80-100%) produce HSV-2 in response to forskolin and HS (43° C., 3 h) treatment for as long as 4 weeks post infection. These findings indicate that ND-PC12 cells can harbor HSV-2 in a cryptic and non-productive state that is reversible. This model has appealing features for studying gene expression during the establishment, maintenance and reactivation phases of the HSV-2 quiescent state in cell culture. Journal of Neuro Virology (2000) 6, 296-302

    Neuronal Cell Model and Methods of Use Therefor

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    The present invention provides, inter alia, a PC12 cell quiescently infected with a neurotropic virus. Preferred quiescently-infected neural cells are those wherein the neurotropic virus is a neurotropic herpes virus. Methods related to these and other materials are also provided

    The Iowa Crop Management Database: An Agronomic and Economic Information Recording Tool

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    The Iowa Crop Management Database (CMD) is designed to record field-by-field agronomic and economic information for crop production in Iowa. Iowa State University Extension is promoting use of such comprehensive records by producers and crop consultants to improve management decisions and farm profitability. Extension staff can use this information and summaries of these records in educational programs, and to document pollution prevention through refined crop management practices. The CMD program is a relational database designed on a model first developed by Pennsylvania State University. The Iowa version was expanded and developed to include a wider range of information resources needed by Iowa producers as a result of a cooperative effort between Extension, state agencies, and agribusiness organizations. The program can meet record-keeping needs for field-by-field agronomic planning, economic analysis, and regulatory documentation. The CMD program is being widely advertised in Iowa by newsletters, direct mailing, brochures displayed at ISU Extension offices, over the World Wide Web and on local radio stations. ISU Extension field specialists with responsibilities for crop production and farm management have been trained in the use of the program. ISU Extension Agribusiness Education is offering a one day short course to train CMD program users. The course will be held on December 10, 1997, January 14 & 21, 1998 and February 11, 1998

    The Lantern Vol. 33, No. 2, May 1967

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    • The Plea • Arrival • Nouvelle • Poem on Theme by Leroi Jones • Night Thoughts • Finals • Caught in the Act • Tomorrow • The Rail • The Price • Lost • It\u27s a Svaden Spring • No Thanks to City Hall • Grinding Them to Dust • Four • Five • Nine • Ten • Twelve • Thirty-Six • Psyched Up and Out • Gutted Gloryhttps://digitalcommons.ursinus.edu/lantern/1091/thumbnail.jp

    Grist: Grid-based Data Mining for Astronomy

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    The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a work ow system, compliant with standards emerging from the grid computing, web services, and virtual observatory communities. This new technology is being used to find high redshift quasars, study peculiar variable objects, search for transients in real time, and fit SDSS QSO spectra to measure black hole masses. Grist services are also a component of the "hyperatlas" project to serve high-resolution multi-wavelength imagery over the Internet. In support of these science and outreach objectives, the Grist framework will provide the enabling fabric to tie together distributed grid services in the areas of data access, federation, mining, subsetting, source extraction, image mosaicking, statistics, and visualization

    Resource Accessibility, Wealth Neutrality, and Tax Yield in Montana

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    Until litigation reaches the point where both sides are willing to listen to data, so much so that states actively monitor themselves and that plaintiffs concede when sophisticated data deny genuine differences, plaintiffs and states and children will suffer equally in lengthy and expensive litigation

    Biofilm and Cell Adhesion Strength on Dental Implant Surfaces via the Laser Spallation Technique

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    OBJECTIVE: The aims of this study are to quantify the adhesion strength differential between an oral bacterial biofilm and an osteoblast-like cell monolayer to a dental implant-simulant surface and develop a metric that quantifies the biocompatible effect of implant surfaces on bacterial and cell adhesion. METHODS: High-amplitude short-duration stress waves generated by laser pulse absorption are used to spall bacteria and cells from titanium substrates. By carefully controlling laser fluence and calibration of laser fluence with applied stress, the adhesion difference between Streptococcus mutans biofilms and MG 63 osteoblast-like cell monolayers on smooth and rough titanium substrates is obtained. The ratio of cell adhesion strength to biofilm adhesion strength (i.e., Adhesion Index) is determined as a nondimensionalized parameter for biocompatibility assessment. RESULTS: Adhesion strength of 143 MPa, with a 95% C.I. (114, 176), is measured for MG 63 cells on smooth titanium and 292 MPa, with a 95% C.I. (267, 306), on roughened titanium. Adhesion strength for S. mutans on smooth titanium is 320 MPa, with a 95% C.I. (304, 333), and remained relatively constant at 332 MPa, with a 95% C.I. (324, 343), on roughened titanium. The calculated Adhesion Index for smooth titanium is 0.451, with a 95% C.I. (0.267, 0.622), which increased to 0.876, with a 95% C.I. (0.780, 0.932), on roughened titanium. SIGNIFICANCE: The laser spallation technique provides a platform to examine the tradeoffs of adhesion modulators on both biofilm and cell adhesion. This tradeoff is characterized by the Adhesion Index, which is proposed to aid biocompatibility screening and could help improve implantation outcomes. The Adhesion Index is implemented to determine surface factors that promote favorable adhesion of cells greater than biofilms. Here, an Adhesion Index ≫ 1 suggests favorable biocompatibility

    The Exceptionally Luminous Type Ia Supernova 2007If

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    SN 2007if was the third over-luminous Type Ia supernova (SN Ia) detected after 2003fg and 2006gz. We present the photometric and spectroscopic observations of the SN and its host by ROTSE-III, HET, and Keck. From the H a line identified in the host spectra, we determine a redshift of 0.0736. At this distance, the SN reached an absolute magnitude of -20.4, brighter than any other SNe Ia ever observed. If the source of luminosity is radioactive decay, a large amount of radioactive nickel (similar to 1.5 M(circle dot)) is required to power the peak luminosity, more than can be produced realistically in a Chandrasekhar mass progenitor. Low expansion velocity, similar to that of 2003fg, is also measured around the maximum light. The observations may suggest that SN 2007if was from a massive white dwarf progenitor, plausibly exploding with mass well beyond 1.4 M(circle dot). Alternatively, we investigate circumstellar interaction that may contribute to the excess luminosity.NASA NNX-08AN25G, NNX-08AV63GNSF AST-0707769, PHY-0801007Australian Research CouncilUniversity of New South WalesUniversity of TexasUniversity of MichiganAstronom
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