7,064 research outputs found

    IUE ultraviolet observations of W UM a Stars

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    International Ultraviolet Explorer observations of four W UMa eclipsing binary systems (44 Boo, VW Cep, W UMa, and epsilon) are discussed. The stars generally show large surface fluxes of high temperature lines (C II, C IV, N V, Si IV) which may result from the high rotational velocities forced by synchronous rotation. High dispersion spectra of the 44 Boo system in the Mg II line enable the individual stellar components to be identified. The line widths and phase variations are consistent with the optically determined spectroscopic orbit. Circumstellar absorption of Mg II may be presented at selected phases

    Pork For Victory

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    Now that our nation has allied itself with other peace-loving countries to completely subdue those nations who have by reason of aggression set out to destroy us, we are realizing the paramount importance of producing more food. With the exception of dairy products, there is probably no single food item which is so vastly important in our war effort as pork. Pork not only offers our fighting forces a meat product highly nutritious and rich in vitamins, but by-products from pork are playing a big role in the manufacture of glycerin, fats, soaps, and ammunition. It would be difficult to estimate the true value of our swine industry as it is related to our war effort

    Study of a soft lander/support module for Mars missions. Volume 3 - Appendixes Final summary report

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    Soft lander support module for Mars missions - lunar module radar evaluation and vernier phase simulatio

    Feshbach Resonances and Limiting Thermodynamics of Strongly Correlated Nucleons

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    A finite temperature model of strongly correlated nucleons with underlying isospin symmetries is developed. The model can be used to study the role of bound states and Feshbach resonances on the thermal properties of a spin 1/2, isospin 1/2 system of protons and neutrons by varying the proton fraction. An analysis of features associated with a universal thermodynamic limit or unitary limit is given. In the limit of very large scattering length, the effective range to quantum thermal wavelength appears as a limiting scale in an interaction energy and equation of state.Comment: 8 pages, 4 figure

    A supersymmetric model of gamma ray bursts

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    We propose a model for gamma ray bursts in which a star subject to a high level of fermion degeneracy undergoes a phase transition to a supersymmetric state. The burst is initiated by the transition of fermion pairs to sfermion pairs which, uninhibited by the Pauli exclusion principle, can drop to the ground state of minimum momentum through photon emission. The jet structure is attributed to the Bose statistics of sfermions whereby subsequent sfermion pairs are preferentially emitted into the same state (sfermion amplification by stimulated emission). Bremsstrahlung gamma rays tend to preserve the directional information of the sfermion momenta and are themselves enhanced by stimulated emission.Comment: published versio

    Eperythrozoonosis in 4-week-old Pigs

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    Eperythrozoon suis is considered to be the major cause of icteroanemia in swine. Knowledge concerning the mode of transmission of eperythrozoonosis is incomplete. Because most cases of eperythrozoonosis occur during the warm months of the year, it has been assumed that dissemination of the blood parasite could be most easily accomplished by bloodsucking arthropod vectors

    Solution of the Bohr hamiltonian for soft triaxial nuclei

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    The Bohr-Mottelson model is solved for a generic soft triaxial nucleus, separating the Bohr hamiltonian exactly and using a number of different model-potentials: a displaced harmonic oscillator in γ\gamma, which is solved with an approximated algebraic technique, and Coulomb/Kratzer, harmonic/Davidson and infinite square well potentials in β\beta, which are solved exactly. In each case we derive analytic expressions for the eigenenergies which are then used to calculate energy spectra. Here we study the chain of osmium isotopes and we compare our results with experimental information and previous calculations.Comment: 13 pages, 9 figure

    Local Projections of Low-Momentum Potentials

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    Nuclear interactions evolved via renormalization group methods to lower resolution become increasingly non-local (off-diagonal in coordinate space) as they are softened. This inhibits both the development of intuition about the interactions and their use with some methods for solving the quantum many-body problem. By applying "local projections", a softened interaction can be reduced to a local effective interaction plus a non-local residual interaction. At the two-body level, a local projection after similarity renormalization group (SRG) evolution manifests the elimination of short-range repulsive cores and the flow toward universal low-momentum interactions. The SRG residual interaction is found to be relatively weak at low energy, which motivates a perturbative treatment

    Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N-nitrosation

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    <b>Background</b>: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. <b>Aims</b>: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. <b>Methods</b>: The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary amines under conditions simulating the proximal stomach. The N-nitrosamines formed were measured by gas chromatography–ion-trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured amperometrically. <b>Results</b>: In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating species to nitric oxide. Addition of ascorbic acid reduced the amount of N-nitrosodimethylamine formed by fivefold, N-nitrosomorpholine by .1000-fold, and totally prevented the formation of N-nitrosodiethylamine and N-nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of Nnitrosodimethylamine, N-nitrosodiethylamine and N-nitrosopiperidine formed by approximately 8-, 60- and 140-fold, respectively, compared with absence of ascorbic acid. <b>Conclusion</b>: The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate nitrosating species by reacting with oxygen in the lipid phase
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