585 research outputs found

    Influence of soil moisture, nitrogen fertilization, and temperature on quality and amino acid composition of Thatcher wheat, The

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    Includes bibliographical references (pages 227-228).The protein content of Thatcher wheat grown in the growth chamber was increased by reduced water supply, nitrogen fertilization, and higher air temperatures. Soil moisture conditions had a greater influence on protein content at higher temperatures, while the largest responses to nitrogen fertilization were obtained at the medium moisture level. Changes in sedimentation value and mixing time were associated with protein content except for plants grown at 62°F. Apparently the low temperature had an adverse effect on gluten quality. The relative distribution of 9 amino acids was significantly correlated with changes in grain protein content. Only 6 amino acids gave similar high correlations with flour protein content and sedimentation value. These differences are explained on the basis of changes in the morphology of the wheat grain and the proportion of flour proteins

    Guidelines, guidelines and more guidelines: And we still do not know how to follow-up patients with breast cancer

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    BACKGROUND: A major challenge facing us is the provision of health care and appropriate allocation of available resources for the treatment of patients with breast cancer. This is of particular concern in the provision of follow-up care. With the increasing incidence of breast cancer and the improvements in survival which have resulted in up to 75% of patients surviving for more than five years, an increasing resource is required. However, there is controversy as to the most appropriate schedule for follow-up of these patients. This brief review has focused on the evidence-base and guidelines that currently exist in the United Kingdom for the follow-up of patients who have been treated for breast cancer. METHODS: A review of the current guidelines published in the United Kingdom for the follow-up of patients with breast cancer (National Institute for Clinical Excellence, Scottish Intercollegiate Guidelines Network, British Association of Surgical Oncology) and the randomised controlled trials evaluating the follow-up of patients with breast cancer was undertaken. RESULTS: The results have demonstrated the different follow-up protocols currently indicated in these guidelines within the same country. Furthermore, the lack of well designed, randomised controlled trials on which to base a follow-up protocol for patients with breast cancer is apparent. CONCLUSION: The evidence-base on which these guidelines have been developed is lacking. It is apparent that well designed randomised controlled trials are needed urgently if we are to understand the most appropriate and effective ways of following up patients with breast cancer

    Relevance of pseudospin symmetry in proton-nucleus scattering

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    The manifestation of pseudospin-symmetry in proton-nucleus scattering is discussed. Constraints on the pseudospin-symmetry violating scattering amplitude are given which require as input cross section and polarization data, but no measurements of the spin rotation function. Application of these constraints to p-58Ni and p-208Pb scattering data in the laboratory energy range of 200 MeV to 800 MeV, reveals a significant violation of the symmetry at lower energies and a weak one at higher energies. Using a schematic model within the Dirac phenomenology, the role of the Coulomb potential in proton-nucleus scattering with regard to pseudospin symmetry is studied. Our results indicate that the existence of pseudospin-symmetry in proton-nucleus scattering is questionable in the whole energy region considered and that the violation of this symmetry stems from the long range nature of the Coulomb interaction.Comment: 22 pages including 9 figures, correction of 1 reference, revision of abstract and major modification of chapter 4, Fig. 6, and Fig. 7; addition of Fig. 8 and Fig.

    Absolute Determination of the 22Na(p,g) Reaction Rate in Novae

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    Gamma-ray telescopes in orbit around the Earth are searching for evidence of the elusive radionuclide 22Na produced in novae. Previously published uncertainties in the dominant destructive reaction, 22Na(p,g)23Mg, indicated new measurements in the proton energy range of 150 to 300 keV were needed to constrain predictions. We have measured the resonance strengths, energies, and branches directly and absolutely by using protons from the University of Washington accelerator with a specially designed beamline, which included beam rastering and cold vacuum protection of the 22Na implanted targets. The targets, fabricated at TRIUMF-ISAC, displayed minimal degradation over a ~ 20 C bombardment as a result of protective layers. We avoided the need to know the stopping power, and hence the target composition, by extracting resonance strengths from excitation functions integrated over proton energy. Our measurements revealed that resonance strengths for E_p = 213, 288, 454, and 610 keV are stronger by factors of 2.4 to 3.2 than previously reported. Upper limits have been placed on proposed resonances at 198-, 209-, and 232-keV. We have re-evaluated the 22Na(p,g) reaction rate, and our measurements indicate the resonance at 213 keV makes the most significant contribution to 22Na destruction in novae. Hydrodynamic simulations including our rate indicate that the expected abundance of 22Na ejecta from a classical nova is reduced by factors between 1.5 and 2, depending on the mass of the white-dwarf star hosting the nova explosion.Comment: 20 pages, 18 figures; shortened paper, accepted in Phys. Rev.

    Probing Correlated Ground States with Microscopic Optical Model for Nucleon Scattering off Doubly-Closed-Shell Nuclei

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    The RPA long range correlations are known to play a significant role in understanding the depletion of single particle-hole states observed in (e, e') and (e, e'p) measurements. Here the Random Phase Approximation (RPA) theory, implemented using the D1S force is considered for the specific purpose of building correlated ground states and related one-body density matrix elements. These may be implemented and tested in a fully microscopic optical model for NA scattering off doubly-closed-shell nuclei. A method is presented to correct for the correlations overcounting inherent to the RPA formalism. One-body density matrix elements in the uncorrelated (i.e. Hartree-Fock) and correlated (i.e. RPA) ground states are then challenged in proton scattering studies based on the Melbourne microscopic optical model to highlight the role played by the RPA correlations. Effects of such correlations which deplete the nuclear matter at small radial distance (r << 2 fm) and enhance its surface region, are getting more and more sizeable as the incident energy increases. Illustrations are given for proton scattering observables measured up to 201 MeV for the 16^{16}O, 40^{40}Ca, 48^{48}Ca and 208^{208}Pb target nuclei. Handling the RPA correlations systematically improves the agreement between scattering predictions and data for energies higher than 150 MeV.Comment: 20 pages, 7 figure

    Cross section and analyzing power of pol{p}p -> pn pi+ near threshold

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    The cross section and analyzing power of the pol{p}p -> pn pi+ reaction near threshold are estimated in terms of data obtained from the pol{p}p -> d pi+ and pp -> pp pi0 reactions. A simple final state interaction theory is developed which depends weakly upon the form of the pion-production operator and includes some Coulomb corrections. Within the uncertainties of the model and the input data, the approach reproduces well the measured energy dependence of the total cross section and the proton analyzing power at a fixed pion c.m. angle of 90deg, from threshold to T_p = 330 MeV. The variation of the differential cross section with pion angle is also very encouraging.Comment: 20 pages, Latex including 4 eps figure

    On the close to threshold meson production in neutron-neutron collisions

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    A method of measuring the close to threshold meson production in neutron-neutron collisions is described where the momenta of the colliding neutrons can be determined with the accuracy obtainable for the proton-proton reaction. The technique is based on the double quasi-free nn --> nn X^0 reaction, where deuterons are used as a source of neutronsComment: 6 pages, 2 figures, to be published in Phys. Lett.

    A Zero-Gravity Instrument to Study Low Velocity Collisions of Fragile Particles at Low Temperatures

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    We discuss the design, operation, and performance of a vacuum setup constructed for use in zero (or reduced) gravity conditions to initiate collisions of fragile millimeter-sized particles at low velocity and temperature. Such particles are typically found in many astronomical settings and in regions of planet formation. The instrument has participated in four parabolic flight campaigns to date, operating for a total of 2.4 hours in reduced gravity conditions and successfully recording over 300 separate collisions of loosely packed dust aggregates and ice samples. The imparted particle velocities achieved range from 0.03-0.28 m s^-1 and a high-speed, high-resolution camera captures the events at 107 frames per second from two viewing angles separated by either 48.8 or 60.0 degrees. The particles can be stored inside the experiment vacuum chamber at temperatures of 80-300 K for several uninterrupted hours using a built-in thermal accumulation system. The copper structure allows cooling down to cryogenic temperatures before commencement of the experiments. Throughout the parabolic flight campaigns, add-ons and modifications have been made, illustrating the instrument flexibility in the study of small particle collisions.Comment: D. M. Salter, D. Hei{\ss}elmann, G. Chaparro, G. van der Wolk, P. Rei{\ss}aus, A. G. Borst, R. W. Dawson, E. de Kuyper, G. Drinkwater, K. Gebauer, M. Hutcheon, H. Linnartz, F. J. Molster, B. Stoll, P. C. van der Tuijn, H. J. Fraser, and J. Blu
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