828 research outputs found

    Mapping Mutual Fund Investor Characteristics and Modeling Switching Behavior

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    Securing a mutual fund that meets investment goals is an important reason why some investors exclusively stay with a particular mutual fund and others switch funds within their fund family. This paper empirically investigates investor attitudes toward mutual funds. Our model, based on investor responses, develops an investor\u27s risk profile variable. Results indicate that regardless of whether the investors invest in nonemployer plans or in both employer and nonemployer plans, they consider their investment risk, fund performance, investment mix, and the capital base of the fund before switching funds. The model developed in this study can also assist in predicting investors\u27 switching behavior

    On the coupling of massless particles to scalar fields

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    It is investigated if massless particles can couple to scalar fields in a special relativistic theory with classical particles. The only possible obvious theory which is invariant under Lorentz transformations and reparametrization of the affine parameter leads to trivial trajectories (straight lines) for the massless case, and also the investigation of the massless limit of the massive theory shows that there is no influence of the scalar field on the limiting trajectories. On the other hand, in contrast to this result, it is shown that massive particles are influenced by the scalar field in this theory even in the ultra-relativistic limit.Comment: 9 pages, no figures, uses titlepage.sty, LaTeX 2.09 file, submitted to International Journal of Theoretical Physic

    A Random Point Field related to Bose-Einstein Condensation

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    The random point field which describes the position distribution of the system of ideal boson gas in a state of Bose-Einstein condensation is obtained through the thermodynamic limit. The resulting point field is given by convolution of two independent point fields: the so called boson process whose generating functional is represented by inverse of the Fredholm determinant for an operator related to the heat operator and the point field whose generating functional is represented by a resolvent of the operator. The construction of the latter point field in an abstract formulation is also given.Comment: 21 page

    Spherical codes, maximal local packing density, and the golden ratio

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    The densest local packing (DLP) problem in d-dimensional Euclidean space Rd involves the placement of N nonoverlapping spheres of unit diameter near an additional fixed unit-diameter sphere such that the greatest distance from the center of the fixed sphere to the centers of any of the N surrounding spheres is minimized. Solutions to the DLP problem are relevant to the realizability of pair correlation functions for packings of nonoverlapping spheres and might prove useful in improving upon the best known upper bounds on the maximum packing fraction of sphere packings in dimensions greater than three. The optimal spherical code problem in Rd involves the placement of the centers of N nonoverlapping spheres of unit diameter onto the surface of a sphere of radius R such that R is minimized. It is proved that in any dimension, all solutions between unity and the golden ratio to the optimal spherical code problem for N spheres are also solutions to the corresponding DLP problem. It follows that for any packing of nonoverlapping spheres of unit diameter, a spherical region of radius less than or equal to the golden ratio centered on an arbitrary sphere center cannot enclose a number of sphere centers greater than one more than the number that can be placed on the region's surface.Comment: 12 pages, 1 figure. Accepted for publication in the Journal of Mathematical Physic

    Building a super-resolution fluorescence cryomicroscope

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    Correlated super-resolution fluorescence microscopy and cryo-electron microscopy enables imaging with both high labeling specificity and high resolution. Naturally, combining two sophisticated imaging techniques within one workflow also introduces new requirements on hardware, such as the need for a super-resolution fluorescence capable microscope that can be used to image cryogenic samples. In this chapter, we describe the design and use of the “cryoscope”; a microscope designed for single-molecule localization microscopy (SMLM) of cryoEM samples that fits right into established cryoEM workflows. We demonstrate the results that can be achieved with our microscope by imaging fluorescently labeled vimentin, an intermediate filament, within U2OS cells grown on EM grids, and we provide detailed 3d models that encompass the entire design of the microscope

    Technology and Aging: An Emerging Research and Development Sector in Maine

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    The authors discuss the importance of research for developing products and services that cater to the needs of a rapidly growing aging population and provide examples of projects underway at the University of Maine. Products designed to improve and protect older adult health and well-being represent a significant opportunity for economic growth in Maine

    Universal correlations of trapped one-dimensional impenetrable bosons

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    We calculate the asymptotic behaviour of the one body density matrix of one-dimensional impenetrable bosons in finite size geometries. Our approach is based on a modification of the Replica Method from the theory of disordered systems. We obtain explicit expressions for oscillating terms, similar to fermionic Friedel oscillations. These terms are universal and originate from the strong short-range correlations between bosons in one dimension.Comment: 18 pages, 3 figures. Published versio

    Vlasov scaling for stochastic dynamics of continuous systems

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    We describe a general scheme of derivation of the Vlasov-type equations for Markov evolutions of particle systems in continuum. This scheme is based on a proper scaling of corresponding Markov generators and has an algorithmic realization in terms of related hierarchical chains of correlation functions equations. Several examples of the realization of the proposed approach in particular models are presented.Comment: 23 page

    Finite one dimensional impenetrable Bose systems: Occupation numbers

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    Bosons in the form of ultra cold alkali atoms can be confined to a one dimensional (1d) domain by the use of harmonic traps. This motivates the study of the ground state occupations λi\lambda_i of effective single particle states ϕi\phi_i, in the theoretical 1d impenetrable Bose gas. Both the system on a circle and the harmonically trapped system are considered. The λi\lambda_i and ϕi\phi_i are the eigenvalues and eigenfunctions respectively of the one body density matrix. We present a detailed numerical and analytic study of this problem. Our main results are the explicit scaled forms of the density matrices, from which it is deduced that for fixed ii the occupations λi\lambda_i are asymptotically proportional to N\sqrt{N} in both the circular and harmonically trapped cases.Comment: 22 pages, 8 figures (.eps), uses REVTeX

    Absence of Edge Localized Moments in the Doped Spin-Peierls System CuGe1x_{1-x}Six_{x}O3_3

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    We report the observation of nuclear quadrupole resonance (NQR) of Cu from the sites near the doping center in the spin-Peierls system CuGe1x_{1-x}Six_{x}O3_3. The signal appears as the satellites in the Cu NQR spectrum, and has a suppressed nuclear spin-lattice relaxation rate indicative of a singlet correlation rather than an enhanced magnetic correlation near the doping center. Signal loss of Cu nuclei with no neighboring Si is also observed. We conclude from these observations that the doping-induced moments are not in the vicinity of the doping center but rather away from it.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let
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