316 research outputs found

    Stream fishes and desirable fish stocks

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    Spherical Hartree-Fock calculations with linear momentum projection before the variation.Part II: Spectral functions and spectroscopic factors

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    The hole--spectral functions and from these the spectroscopic factors have been calculated in an Galilei--invariant way for the ground state wave functions resulting from spherical Hartree--Fock calculations with projection onto zero total linear momentum before the variation for the nuclei 4He, 12C, 16O, 28Si, 32S and 40Ca. The results are compared to those of the conventional approach which uses the ground states resulting from usual spherical Hartree--Fock calculations subtracting the kinetic energy of the center of mass motion before the variation and to the results obtained analytically with oscillator occupations.Comment: 16 pages, 22 postscript figure

    Nuclear symmetry energy effects on neutron stars properties

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    We construct a class of nuclear equations of state based on a schematic potential model, that originates from the work of Prakash et. al. \cite{Prakash-88}, which reproduce the results of most microscopic calculations. The equations of state are used as input for solving the Tolman-Oppenheimer-Volkov equations for corresponding neutron stars. The potential part contribution of the symmetry energy to the total energy is parameterized in a generalized form both for low and high values of the baryon density. Special attention is devoted to the construction of the symmetry energy in order to reproduce the results of most microscopic calculations of dense nuclear matter. The obtained nuclear equations of state are applied for the systematic study of the global properties of a neutron star (masses, radii and composition). The calculated masses and radii of the neutron stars are plotted as a function of the potential part parameters of the symmetry energy. A linear relation between these parameters, the radius and the maximum mass of the neutron star is obtained. In addition, a linear relation between the radius and the derivative of the symmetry energy near the saturation density is found. We also address on the problem of the existence of correlation between the pressure near the saturation density and the radius.Comment: 17 pages, 25 figure

    Синтез и антиинфекционное протективное действие β-циклогексилметил- и β-2-циклогексилэтилгликозидов мурамоилдипептида

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    Осуществлен синтез β-циклогексилметил- и β-2-циклогексилэтилгликозидов мурамоилдипептида. Исходные перацетилированные β-циклогексилалкилглюкозаминиды были получены оксазолиновым методом. Установлено, что β-циклогексилметил- и β-(2-циклогексилэтил)-МДП обладают высоким антиинфекционным протективным эффектом при поражении мышей летальной дозой Staphylococcus aureus.Здійснено синтез β-циклогексилметил- і β-2-циклогексилетил глікозиді в мурамоїлдипептиду. Вихідні перацетильовані (β-циклогексилалкілглюкозамініди були отримані за оксазоліновим методом. Встановлено, що β-циклогексилметил- і β-(2-циклогексилетил)-МДП володіють високим антиінфекційним протективним ефектом при поразці мишей летальною дозою Staphylococcus aureus.The synthesis of β-cyclohexylmethyl- and β-2-cyclohexylethylglycosides of muramyldipeptide has been carried out. The starting peracetates of β-cyclohexylalkylglucosaminides have been obtained by the oxazoline method. It been found that β-cyclohexylmethyl- and β-(2-cyclohexylethyl)-MDP have a high anti-infection protective effect against the lethal dose of Staphylococcus aureus in mice

    The effects of multidisciplinary rehabilitation: RePCa-a randomised study among primary prostate cancer patients

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    BACKGROUND: The objective of this study is the effectiveness of multidisciplinary rehabilitation on treatment-related adverse effects after completed radiotherapy in patients with prostate cancer (PCa). METHODS: In a single-centre oncology unit in Odense, Denmark, 161 PCa patients treated with radiotherapy and androgen deprivation therapy were randomly assigned to either a programme of two nursing counselling sessions and two instructive sessions with a physical therapist (n=79) or to usual care (n=82). Primary outcome was Expanded Prostate Cancer Index Composite (EPIC-26) urinary irritative sum-score. Before radiotherapy, pre-intervention 4 weeks after radiotherapy, and after a 20-week intervention, measurements included self-reported disease-specific quality of life (QoL; EPIC-26, including urinary, bowel, sexual, and hormonal symptoms), general QoL (Short-form-12, SF-12), pelvic floor muscle strength (Modified Oxford Scale), and pelvic floor electromyography. Intension-to-treat analyses were made with adjusted linear regression. RESULTS: The intervention improved, as compared with controls, urinary irritative sum-score 5.8 point (Cohen's d=0.40; P=0.011), urinary sum-score (d=0.34; P=0.023), hormonal sum-score (d=0.19; P=0.018), and the SF-12 Physical Component Summary, d=0.35; P=0.002. Patients with more severe impairment gained most. Pelvic floor muscle strength measured by electromyography declined in both groups, P=0.0001. CONCLUSION: Multidisciplinary rehabilitation in irradiated PCa patients improved urinary and hormonal symptoms, and SF-12 physical QoL

    Threshold Effects in Multi-channel Coupling and Spectroscopic Factors in Exotic Nuclei

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    In the threshold region, the cross section and the associated overlap integral obey the Wigner threshold law that results in the Wigner-cusp phenomenon. Due to flux conservation, a cusp anomaly in one channel manifests itself in other open channels, even if their respective thresholds appear at a different energy. The shape of a threshold cusp depends on the orbital angular momentum of a scattered particle; hence, studies of Wigner anomalies in weakly bound nuclei with several low-lying thresholds can provide valuable spectroscopic information. In this work, we investigate the threshold behavior of spectroscopic factors in neutron-rich drip-line nuclei using the Gamow Shell Model, which takes into account many-body correlations and the continuum effects. The presence of threshold anomalies is demonstrated and the implications for spectroscopic factors are discussed.Comment: Accepted in Physical Review C Figure correcte

    Two-neutron separation energies, binding energies and phase transitions in the interacting boson model

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    In the framework of the interacting boson model the three transitional regions (rotational-vibrational, rotational-γ\gamma-unstable and, vibrational-γ\gamma-unstable transitions) are reanalyzed. A new kind of plot is presented for studying phase transitions in finite systems such as atomic nuclei. The importance of analyzing binding energies and not only energy spectra and electromagnetic transitions, describing transitional regions is emphasized. We finally discuss a number of realistic examples.Comment: 34 pages, TeX (ReVTeX). 12 ps figures. 3 tables. Submitted to Nucl. Phys.

    Hyperon-nucleon scattering and hyperon masses in the nuclear medium

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    We analyze low-energy hyperon-nucleon scattering using an effective field theory in next-to-leading order. By fitting experimental cross sections for laboratory hyperon momenta below 200 MeV/c and using information from the hypertriton we determine twelve contact-interaction coefficients. Based on these we discuss the low-density expansion of hyperon mass shifts in the nuclear medium.Comment: 10 pages, 2 figure

    SU(3) realization of the rigid asymmetric rotor within the IBM

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    It is shown that the spectrum of the asymmetric rotor can be realized quantum mechanically in terms of a system of interacting bosons. This is achieved in the SU(3) limit of the interacting boson model by considering higher-order interactions between the bosons. The spectrum corresponds to that of a rigid asymmetric rotor in the limit of infinite boson number.Comment: 9 pages, 2 figures, LaTeX, epsfi

    Relativistic Contributions to Deuteron Photodisintegration in the Bethe-Salpeter Formalism

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    In plane wave one-body approximation the reaction of deuteron photodisintegration is considered in the framework of the Bethe-Salpeter formalism for two-nucleon system. Results are obtained for deuteron vertex function, which is the solution of the homogeneous Bethe-Salpeter equation with a multi-rank separable interaction kernel, with a given analytical form. A comparison is presented with predictions of non-relativistic, quasipotential approaches and the equal time approximation. It is shown that important contributions come from the boost in the arguments of the initial state vertex function and the boost on the relative energy in the one-particle propagator due to recoil.Comment: 29 pages, 6 figure
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