1,982 research outputs found

    Experimental Studies of the NaCs 53Π0 and a3Σ+ States

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    We report high resolution measurements of 372 NaCs 53Π0(v, J) ro-vibrational level energies in the range 0 ≤ v ≤ 22. The data have been used to construct NaCs 53Π0 potential energy curves using the Rydberg–Klein-Rees and inverted perturbation approximation methods. Bound-free 53Π0(v, J) → 1(a)3Σ+ emission has also been measured, and is used to determine the repulsive wall of the 1(a)3Σ+ state and the 53Π0 → 1(a)3Σ+ relative transition dipole moment function. Hyperfine structure in the 53Π0 state has not been observed in this experiment. This null result is explained using a simple vector coupling model

    Production of J/ψJ/\psi-pairs at HERA-N\vec{{\rm N}}

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    The production of J/ψJ/\psi-pairs as a possible measure of the polarized gluon distribution ΔG(x)\Delta G(x) is studied for proton--nucleon collisions at \sqrt{s} =40\;\mbox{GeV}^2 (HERA-N\vec{{\rm N}}). Possibilities of reconstructing the helicity state of at least one of the J/ψJ/\psi's are critically reviewed. The observation of production asymmetries in the single polarized mode of HERA-N\vec{{\rm N}} is found to be not feasible.Comment: 8 pages, LATeX, 3 figures availabe as .uu-fil

    Collisional Transfer of Population and Orientation in NaK

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    We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser- induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A1Σ +(v 0=16, J 0 ) ← X1Σ +(v 00=0, J 0 ± 1) transition, creating an orientation (non-uniform MJ0 level distribution) in both levels. The linearly polarized probe laser is scanned over various 31Π(v, J 0±1) ← A1Σ +(v 0=16, J 0 ) transitions. The probe laser passes through a crossed linear polarizer before detection, and signal is recorded if the probe laser polarization has been modified by the vapor (which occurs when it comes into resonance with an oriented level). Using both spectroscopic methods, analysis of weak collisional satellite lines adjacent to these directly populated lines, as a function of argon buffer gas pressure and cell temperature, allows us to discern separately the effects collisions with argon atoms and potassium atoms have on the population and orientation of the molecule. In addition, code has been written which provides a theoretical analysis of the process, through a solution of the density matrix equations of motion for the system

    Polarization Spectroscopy and Collisions in NaK

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    We report current work to study transfer of population and orientation in collisions of NaK molecules with argon and potassium atoms using polarization labeling (PL) and laser-induced fluorescence (LIF) spectroscopy. In the PL experiment, a circularly polarized pump laser excites a specific NaK A1Σ +(v=16, J) ← X1Σ +(v=0, J ± 1) transition, creating an orientation (non-uniform MJ level distribution) in both levels. The linear polarized probe laser is scanned over various 3 1Π(v=8, J 0 ± 1) ← A1Σ +(v=16, J 0 ) transitions. The probe laser passes through a crossed linear polarizer before detection, and signal is recorded if the probe laser polarization has been modified by the vapor (which occurs when it comes into resonance with an oriented level). In addition to strong direct transitions (J 0 = J), we also observe weak collisional satellite lines (J 0 = J ±n with n = 1, 2, 3, ...) indicating that orientation is transferred to adjacent rotational levels during a collision. An LIF experiment (with linear polarized pump and probe beams) gives information on the collisional transfer of population. From these data, cross sections for both processes can be determined. We experimentally distinguish collisions of NaK with argon atoms from collisions with alkali atoms

    Results on the nucleon spin structure

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    SMC performed an investigation of the spin structure of the nucleon by measuring deep inelastic scattering of polarised muons off polarised protons and deuterons. A summary of the results for spin structure functions and sum rules is given.Comment: 8 pages, LaTeX, Talk given at the Workshop on "Symmetry and Spin - PRAHA98", Prag, September 1998. Proceedings to be published by Czech. Journ. Phy

    Bone Marrow Colony-Formation In Vitro After Infection of Genetically Defined Inbred Mice with Candida Albicans

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    The effect of C. albicans infection on the production of haematopoietic precursor cells in the bone marrow of CBA/CaH and BALB/c mice was evaluated by assay of colony formation in vitro. In immunocompetent mice, neither systemic nor oral infection induced significant alterations in colony formation by bone marrow from the two mouse strains, and Candida infection did not alter the proportion of morphological cell types in the colonies. However, the number of neutrophil-like was relatively greater in colonies derived from acutely infected CBA/CaH nude mice than in those from BALB/c nude mice, whereas small mononuclear cells were present in higher proportions in the latter strain. In both strains of nude mice, there was an increase in colony formation at 6 days after oral infection, but at 8 weeks, when the infection had become chronic, the production of bone marrow cells by CBA/CaH nude mice was significantly less than that by BALB/c nude mice. Reconstitution of nude mice with syngeneic lymphocytes enhanced the production of bone marrow precursor cells by BALB/c, but not by CBA/CaH mice, suggesting that T cells can enhance host resistance by promoting the colony-forming response of the bone marrow in BALB/c mice that are genetically resistant to tissue damage, but not in CBA/CaH that are prone to severe lesions. Finally, culture with Candida antigen in vitro decreased the number of colony-forming cells in cultures from CBA/CaH, but not from BALB/c mice

    The Origin of Primordial Dwarf Stars and Baryonic Dark Matter

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    I present a scenario for the production of low mass, degenerate dwarfs of mass >0.1M>0.1 M_{\odot} via the mechanism of Lenzuni, Chernoff & Salpeter (1992). Such objects meet the mass limit requirements for halo dark matter from microlensing surveys while circumventing the chemical evolution constraints on normal white dwarf stars. I describe methods to observationally constrain this scenario and suggest that such objects may originate in small clusters formed from the thermal instability of shocked, heated gas in dark matter haloes, such as suggested by Fall & Rees (1985) for globular clusters.Comment: TeX, 4 pages plus 2 postscript figures. To appear in Astrophysical Journal Letter

    The connection between single transverse spin asymmetries and the second moment of g2g_2

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    We point out that the size of the photon single spin asymmetry in high--energy proton proton collisions with one transversely polarized proton can be related to d(2)d^{(2)}, the twist three contribution to the second moment of g2g_2. Both quantities should be measured in the near future. The first was analysed by Qiu and Sterman, the second was estimated by Balitsky, Braun, and Kolesnichenko. Both experiments measure effectively the strength of the collective gluon field in the nucleon oriented relative to the nucleon spin. The sum rule results suggest that the single spin asymmetry is rather small for the proton, but could be substantial for the neutron.Comment: 6 pages, UFTP preprint 348/199

    Gluon Fusion: A Probe of Higgs Sector CP Violation

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    We demonstrate that CP violation in the Higgs sector, \eg\ of a multi-doublet model, can be directly probed using gluon-gluon collisions at the SSC. % requires phyzzx.tex macro packageComment: UCD-93-

    Lean towards learning: connecting Lean Thinking and human resource management in UK higher education

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    From its origins in the automotive industry, Lean Thinking is increasingly being seen as a solution to problems of efficiency and quality in other industries and sectors. In recent years attempts have been made to transfer Lean principles and practice to the higher education sector with indications of mixed consequences and debate over its suitability. This paper contributes to the debate by drawing evidence from thirty-four interviews conducted across two UK universities that have implemented Lean in some of their activities and we pay particular attention to the role of the HR function in facilitating its introduction. The findings suggest there are problems in understanding, communicating and transferring Lean Thinking in the higher education context; that, despite HR systems being vital facets of Lean, HR professionals are excluded from participation; and that as a consequence the depth and breadth of Lean application in the two institutions is very limited
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