2,030 research outputs found

    Bosonic molecules in rotating traps

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    We present a variational many-body wave function for repelling bosons in rotating traps, focusing on rotational frequencies that do not lead to restriction to the lowest Landau level. This wave function incorporates correlations beyond the Gross-Pitaevskii (GP) mean field approximation, and it describes rotating boson molecules (RBMs) made of localized bosons that form polygonal-ring-like crystalline patterns in their intrinsic frame of reference. The RBMs exhibit characteristic periodic dependencies of the ground-state angular momenta on the number of bosons in the polygonal rings. For small numbers of neutral bosons, the RBM ground-state energies are found to be always lower than those of the corresponding GP solutions, in particular in the regime of GP vortex formation.Comment: To appear in Phys. Rev. Lett. LATEX, 5 pages with 5 figures. For related papers, see http://www.prism.gatech.edu/~ph274cy

    Medical card of a pulmonary tuberculosis in-patient

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    ИСТОРИЯ БОЛЕЗНИОБСЛЕДОВАНИЕ БОЛЬНОГОТУБЕРКУЛЕЗ ЛЕГКИХУЧЕБНО-МЕТОДИЧЕСКИЕ ПОСОБИЯФТИЗИОПУЛЬМОНОЛОГИЯУчебно-методическое пособие предназначено для самостоятельной подготовки к курации больных в клинике и написанию учебной истории болезни

    Crystalline boson phases in harmonic traps: Beyond the Gross-Pitaevskii mean field

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    Strongly repelling bosons in two-dimensional harmonic traps are described through breaking of rotational symmetry at the Hartree-Fock level and subsequent symmetry restoration via projection techniques, thus incorporating correlations beyond the Gross-Pitaevskii (GP) solution. The bosons localize and form polygonal-ring-like crystalline patterns, both for a repulsive contact potential and a Coulomb interaction, as revealed via conditional-probability-distribution analysis. For neutral bosons, the total energy of the crystalline phase saturates in contrast to the GP solution, and its spatial extent becomes smaller than that of the GP condensate. For charged bosons, the total energy and dimensions approach the values of classical point-like charges in their equilibrium configuration.Comment: Published version. Typos corrected. REVTEX4; 5 pages with 3 PS figures. For related papers, see http://www.prism.gatech.edu/~ph274c

    The KπK\pi form factors from Analyticity and Unitarity

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    Analyticity and unitarity techniques are employed to obtain bounds on the shape parameters of the scalar and vector form factors of semileptonic Kl3K_{l3} decays. For this purpose we use vector and scalar correlators evaluated in pQCD, a low energy theorem for scalar form factor, lattice results for the ratio of kaon and pion decay constants, chiral perturbation theory calculations for the scalar form factor at the Callan-Treiman point and experimental information on the phase and modulus of KπK\pi form factors up to an energy \tin=1 {\rm GeV}^2. We further derive regions on the real axis and in the complex-energy plane where the form factors cannot have zeros.Comment: 6 pages, 5 figures; Seminar given at DAE-BRNS Workshop on Hadron Physics Bhabha Atomic Research Centre, Mumbai, India October 31-November 4, 2011, submitted to Proceeding

    Seasonal abundance of small cladocerans in Lake Mangakaware, Waikato, New Zealand

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    The seasonal changes in the dynamics and life histories of the Cladocera in Lake Mangakaware, North Island, New Zealand, were studied over 19 months by sampling at weekly or 2-weekly intervals. Lake Mangakaware is a 13.3 ha polymictic lake with high nutrient status, low Secchi disc transparencies, and an unstable thermal regime. The four planktonic cladoceran species (Bosmina longirostris, B. meridionalis, Ceriodaphnia pulchella, and C. dubia) exhibited disjunct population maxima. Only B. longirostris was perennially present. All species exhibited low fecundities and low lipid content, indicating that food resources were limited and that competitive interactions and resistance to starvation were probably important in determining species success. Increases in body size in cooler seasons were unrelated to clutch size, giving further support for the view that available food was limited. These results are consistent with previous experimental findings that subtle differences in life history can determine seasonal success and the outcome of competition between similar species

    Study of 6^{6}He+12^{12}C Elastic Scattering Using a Microscopic Optical Potential

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    The 6^6He+12^{12}C elastic scattering data at beam energies of 3, 38.3 and 41.6 MeV/nucleon are studied utilizing the microscopic optical potentials obtained by a double-folding procedure and also by using those inherent in the high-energy approximation. The calculated optical potentials are based on the neutron and proton density distributions of colliding nuclei established in an appropriate model for 6^6He and obtained from the electron scattering form factors for 12^{12}C. The depths of the real and imaginary parts of the microscopic optical potentials are considered as fitting parameters. At low energy the volume optical potentials reproduce sufficiently well the experimental data. At higher energies, generally, additional surface terms having form of a derivative of the imaginary part of the microscopic optical potential are needed. The problem of ambiguity of adjusted optical potentials is resolved requiring the respective volume integrals to obey the determined dependence on the collision energy. Estimations of the Pauli blocking effects on the optical potentials and cross sections are also given and discussed. Conclusions on the role of the aforesaid effects and on the mechanism of the considered processes are made.Comment: 12 pages, 9 figures, accepted for publication in Physical Review

    Calculations of 8^{8}He+p Elastic Cross Sections Using Microscopic Optical Potential

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    An approach to calculate microscopic optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the 8^8He+p elastic scattering data at energies of tens of MeV/nucleon (MeV/N). The neutron and proton density distributions obtained in different models for 8^{8}He are utilized in the calculations of the differential cross sections. The role of the spin-orbit potential is studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies of 15.7, 26.25, 32, 66 and 73 MeV/N is performed. The problem of the ambiguities of the depths of each component of the optical potential is considered by means of the imposed physical criterion related to the known behavior of the volume integrals as functions of the incident energy. It is shown also that the role of the surface absorption is rather important, in particular for the lowest incident energies (e.g., 15.7 and 26.25 MeV/nucleon).Comment: 11 pages, 7 figures, accepted for publication in Physical Review

    Permafrost degradation risk zone assessment using simulation models

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    In this proof-of-concept study we focus on linking large scale climate and permafrost simulations to small scale engineering projects by bridging the gap between climate and permafrost sciences on the one hand and on the other technical recommendation for adaptation of planned infrastructures to climate change in a region generally underlain by permafrost. We present the current and future state of permafrost in Greenland as modelled numerically with the GIPL model driven by HIRHAM climate projections up to 2080. We develop a concept called Permafrost Thaw Potential (PTP), defined as the potential active layer increase due to climate warming and surface alterations. PTP is then used in a simple risk assessment procedure useful for engineering applications. The modelling shows that climate warming will result in continuing wide-spread permafrost warming and degradation in Greenland, in agreement with present observations. We provide examples of application of the risk zone assessment approach for the two towns of Sisimiut and Ilulissat, both classified with high PTP
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