7,360 research outputs found

    TeV gamma rays and cosmic rays from the nucleus of M87, a mis-aligned BL Lac object

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    The unresolved nuclear region of M87 emits strong non-thermal emission from radio to X-rays. Assuming this emission to originate in the pc scale jet aligned at Ξ∌30∘\theta \sim 30^\circ to the line of sight, we interpret this emission in the context of the Synchrotron Proton Blazar (SPB) model. We find the observed nuclear jet emission to be consistent with M87 being a mis-aligned BL Lac Object and predict gamma-ray emission extending up to at least 100 GeV at a level easily detectable by GLAST and MAGIC, and possibly by VERITAS depending on whether it is high-frequency or low-frequency peaked. Predicted neutrino emission is below the sensitivity of existing and planned neutrino telescopes. Ultra-high energy neutrons produced in pion photoproduction interactions decay into protons after escaping from the host galaxy. Because energetic protons are deflected by the intergalactic magnetic field, the protons from the decay of neutrons emitted in all directions, including along the jet axis where the Doppler factor and hence emitted neutron energies are higher, can contribute to the observed ultra-high energy cosmic rays. We consider the propagation of these cosmic ray protons to Earth and conclude that M87 could account for the observed flux if the extragalactic magnetic field topology were favourable.Comment: 17 pages, 6 figures. 3 additional references plus minor changes, acctepted for publication in Astroparticle Physic

    Identification of zeta-carotene desaturase genes from durum wheat

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    Non-Peer ReviewedYellow pigment is an important quality trait in durum wheat (Triticum turgidum L. var durum). Few genes within the pathway responsible for carotenoid biosynthesis have yet to been identified in durum wheat. Zeta-carotene desaturase (ZDS) is an enzyme involved in carotenoid biosynthesis, and variation in the gene(s) coding for ZDS may partially explain the variation observed in endosperm color among durum wheat cultivars. For this study, a PCR strategy was used to clone and sequence greater than 1200 bp of the Zds genes from durum cultivars Kofa (high pigment) and W9262-D063 (medium pigment). Comparison of partial nucleotide sequences indicated the presence of four Zds genes which we temporarily designated as tdZds1, tdZds2, tdZds3, and tdZds4. Since durum wheat is a tetraploid, the presence of four genes suggests that the Zds gene may in fact be duplicated in the durum wheat genome, with two sets of homeologous genes. However, we have only obtained single clones of Zds2 and Zds4 from each of the two parents, and these results will need to be confirmed. However, we are currently in the process of mapping Zds1 and Zds3 to determine their role in the expression of yellow pigment concentration in durum wheat

    Race Cartels: How Constructor Collaboration Is Curbing Innovation in Formula 1

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    Formula 1 is in the midst of a copycat scandal: technology has made it possible for teams to reverse engineer clones of competitors’ race cars. This is a less than ideal state of affairs for the championship series, which prides itself on being the pinnacle of motorsport and automotive innovation, thanks in large part to the cars’ rapid rate of technological advancement. In order to address this problem, the FĂ©dĂ©ration Internationale de l’Automobile (FIA), Formula 1’s governing body, must increase independent innovation efforts by amending the technical regulations to restrict the extent of presently allowed inter-team collaboration. Worried that the sport was becoming a “copying championship,” the FIA adopted new measures that ban extreme reverse engineering methods. Because these new FIA regulations do not limit the degree of coordinated conduct between teams, this approach will likely fail to remedy the sport’s copying problem because team plagiarism is an anticompetitive side effect of this collusive behavior. The FIA addresses the copying problem as one of trade secret misappropriation. By contrast, this Note approaches the issue as one of unregulated anticompetitive conduct. Analyzing the technical partnerships in Formula 1 under antitrust law elucidates their harmful effects on the racing series. This Note urges the FIA to adopt measures that limit Formula 1 teams’ ability to collaborate, before the “A-B team” phenomenon further diminishes the sport’s innovation efforts

    Notes on the Diatom Cylindrotheca gracilis (Breh. ex Kutz) Grun: Its Ecology and Distribution

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    The diatom Cylindrotheca gracilis (Breb. ex Kutz) Grun., considered by some as a Brackish water species, was found as a massive growth in isolated pools along Dugout Creek, Dickinson County, Iowa. Chemical analyses show the water to be high in S04, Mg., Ca., and low in Cl ions. Comparative data from other waters in the United States containing this species shows similar pattern of high conductivity suggesting that factors other than chlorides might be more critical for growth. United States distribution for this diatom includes: Maryland (brackish water), Ohio (fresh water) and Iowa (fresh water)

    An explicit numerical model to simulate upwelling events

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    A three-dimensional numerical model for upwelling has been developed and tested under various boundary conditions. Gridsize and bottom topography are variable; the driving force is windstress. A version o f the model was applied to data from the “ Upwelling 75” experim ent. Certain wind-induced events observed in the data are reproduced reasonably well, although wind input is done by m eans of linear approx­ imation. Typical upwelling conditions can be achieved and the influence of bottom topography can be shown

    The Hamburg ocean carbon cycle circulation model

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    AVIRIS ground data-processing system

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    The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been under development at JPL for the past four years. During this time, a dedicated ground data-processing system has been designed and implemented to store and process the large amounts of data expected. This paper reviews the objectives of this ground data-processing system and describes the hardware. An outline of the data flow through the system is given, and the software and incorporated algorithms developed specifically for the systematic processing of AVIRIS data are described
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