2,322 research outputs found

    Crustal structure beneath the Trondelag Platform and adjacent areas of the Mid-Norwegian margin, as derived from wide-angle seismic and potential field data

    Get PDF
    The outer mid-Norwegian margin is characterized by strong breakup magmatism and has been extensively surveyed. The crustal structure of the inner continental shelf, however, is less studied, and its relation to the onshore geology, Caledonian structuring, and breakup magmatism remains unclear. Two Ocean Bottom Seismometer profiles were acquired across the Trøndelag Platform in 2003, as part of the Euromargins program. Additional-land stations recorded the marine shots. The P-wave data were modeled by ray-tracing, supported by gravity modeling. Older multi-channel seismic data allowed for interpretation of stratigraphy down to the top of the Triassic. Crystalline basement velocity is ~6 km s-1 onshore. Top basement is difficult to identify offshore, as velocities (5.3-5.7 km s-1) intermediate between typical crystalline crust and Mesozoic sedimentary strata appear 50-80 km from the coast. This layer thickens towards the Klakk-Ytreholmen Fault Complex and predates Permian and later structur-ing. The velocities indicate sedimentary rocks, most likely Devonian. Onshore late- to post-Caledonian detachments have been proposed to extend offshore, based on the magnetic anomaly pattern. We do not find the expected correlation between upper basement velocity structure and detachments. However, there is a distinct, dome-shaped lower-crustal body with a velocity of 6.6-7.0 km s-1. This is thickest under the Froan Basin, and the broad magnetic anomaly used to delineate the detachments correlates with this. The proposed offshore continuation of the detachments thus appears- unreliable. While we find indications of high density and velocity (~7.2 km s-1) lower crust under the Rås Basin, similar to the proposed igneous underplating of the outer margin, this is poorly constrained near the end of our profiles. The gravity field indicates that this body may be continuous from the pre-breakup basement structures of the Utgard High to the Frøya High, suggesting that it could be an island arc or oceanic terrane-accreted during the Caledonian orogeny. Thus, we find no clear evidence of early Cenozoic igneous underplating of the inner part of the shelf

    The water stability of shrimp diets with various polysaccharides as a binding agent

    Get PDF
    The water stability of shrimp (Penaeus monodon) diets with various polysaccharides as binding agents were tested without steaming. The diet with alginate showed the best water stability and did not completely disintegrate in 24 hours. However, the use of alginate is dependent on cost and availability, so alternate choices may be a combination of sago palm starch and wheat flour or glutinous rice flour

    Improvement of diet attractability for Penaeus monodon by supplementing various attractants

    Get PDF
    An experiment was undertaken to test the effect of supplemental krill meal, earthworm meal, glycine, sucrose or mussel water on diet attractibility of Penaeus monodon. Only glycine or mussel water significantly improved diet attractibility

    Topology of Neutral Hydrogen Within the Small Magellanic Cloud

    Full text link
    In this paper, genus statistics have been applied to an HI column density map of the Small Magellanic Cloud in order to study its topology. To learn how topology changes with the scale of the system, we provide the study of topology for column density maps at varying resolution. To evaluate the statistical error of the genus we randomly reassign the phases of the Fourier modes while keeping the amplitudes. We find, that at the smallest scales studied (40pc≤λ≤80pc40 {pc}\leq\lambda\leq 80 {pc}) the genus shift is in all regions negative, implying a clump topology. At the larger scales (110pc≤λ≤250pc110 {pc}\leq\lambda\leq 250 {pc}) the topology shift is detected to be negative in 4 cases and positive (``swiss cheese'' topology) in 2 cases. In 4 regions there is no statistically significant topology shift at large scales

    Using GEANT to Model Calrimeter Response for Electromagnetic Cascades from Nucleus-Nucleus Interactions in a Cosmic Ray Detector

    Get PDF
    Ascintillating optical fiber calorimeter (SOFCAL) is being developed by NASA/Marshall Space Flight Center for use in balloon-borne experiments to study the spectrum of high-energy cosmic rays and gamma rays. SOFCAL will not saturate for long exposures and the calorimeter willbe useful in emulsion chambers to study primary cosmic-ray nuclei with energies from 100 GeV to 1,000 TeV. The event generator FRITIOF was used to model the collision of a cosmic-ray projectile with a target nucleus inan emulsion chamber. The measurements of charged particles from the interaction in the emulsions are related to the energy of the primary cosmic ray nucleus-nucleus interaction, computer simulations of electromagnetic cascades allow computation of the energy ££y deposited indifferent regions of the calorimeter. The Monte Carlo program GEANT was used to model SOFCAL response to incident gamma rays and to compute the measure of energy deposition X£y in different layers ofthe calorimeter within the emulsion chamber. The partial coefficient o finelasticity kr defined by 1JE Y = kY E0 ,was computed for different energies Eo of primary cosmic rays. The were computed and compared with existing calorimeter data. Funding was provided by the NASA/University Joint Venture (JOVE) Program
    • …
    corecore