3,451 research outputs found

    The University of Alaska Anchorage experience

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    In the fall 2005, when two faculty librarians at the University of Alaska Anchorage’s (UAA) Consortium Library realized that three people on the library staff were enrolled in library school, they saw the perfect opportunity to start a discussion group that would benefit both currently employed librarians and students entering the information field. The original three students were enrolled in the MLIS distance program at the University of Washington, working in the Consortium Library, and taking classes part-time. The two faculty librarians had been out of library school for more than ten years by then, so the intent was to organize a forum with an informal, relaxed atmosphere that would be an engaging way to keep up with current curricula, to learn about class projects the students were working on, and to hear about their experiences. While the librarians learned from the students, the students could, in turn, share their new expertise with the library faculty. That was the beginning of what came to be known as FLIP: Future Library and Information Science People.1 Now, nearly seven years later, FLIP is still going strong. What the name stands for has changed slightly—to Future Librarians and Information Professionals—and the membership has expanded to include anyone considering a career as a librarian or enrolling in an MLS or MLIS program. Characterizing FLIP as a “mentoring” program misses the mark, since so much more than just mentoring is happening. Because the benefits go both ways, we prefer the term “un-mentoring” to describe FLIP. Regardless of its definition or description, however, the original purpose remains the same: to provide an informal discussion forum that enriches library school studies with librarian expertise, advice, and insight

    Measuring time preferences

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    We review research that measures time preferences—i.e., preferences over intertemporal tradeoffs. We distinguish between studies using financial flows, which we call “money earlier or later” (MEL) decisions and studies that use time-dated consumption/effort. Under different structural models, we show how to translate what MEL experiments directly measure (required rates of return for financial flows) into a discount function over utils. We summarize empirical regularities found in MEL studies and the predictive power of those studies. We explain why MEL choices are driven in part by some factors that are distinct from underlying time preferences.National Institutes of Health (NIA R01AG021650 and P01AG005842) and the Pershing Square Fund for Research in the Foundations of Human Behavior

    Pion Scalar Density and Chiral Symmetry Restoration at Finite Temperature and Density

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    This paper is devoted to the evaluation of the pionic scalar density at finite temperature and baryonic density. We express the latter effect in terms of the nuclear response evaluated in the random phase approxima- tion. We discuss the density and temperature evolution of the pionic density which governs the quark condensate evolution. Numerical evalua- tions are performed.Comment: 13 pages, Latex File, 10 eps Figure

    Chiral Dynamics of Deeply Bound Pionic Atoms

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    We present and discuss a systematic calculation, based on two-loop chiral perturbation theory, of the pion-nuclear s-wave optical potential. A proper treatment of the explicit energy dependence of the off-shell pion self-energy together with (electromagnetic) gauge invariance of the Klein-Gordon equation turns out to be crucial. Accurate data for the binding energies and widths of the 1s and 2p levels in pionic ^{205}Pb and ^{207}Pb are well reproduced, and the notorious "missing repulsion" in the pion-nuclear s-wave optical potential is accounted for. The connection with the in-medium change of the pion decay constant is clarified.Comment: preprint ECT*-02-16, 4 pages, 3 figure

    Evaluation of the ππ\pi\pi scattering amplitude in the σ\sigma-channel at finite density

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    The ππ\pi\pi scattering amplitude in the σ\sigma-channel is studied at finite baryonic density in the framework of a chiral unitary approach which successfully reproduces the meson meson phase shifts and generates the f0f_0 and σ\sigma resonances in vacuum. We address here a new variety of mechanisms recently suggested to modify the ππ\pi\pi interaction in the medium, as well as the role of the ss-wave selfenergy, in addition to the pp-wave, in the dressing of the pion propagators.Comment: 26 pages, 17 figure

    Gas Content, Size, Temperature and Velocity Effects on Cavitation Inception Internal Report No. 31

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    Gas content, size temperature, and velocity effects on Venturi cavity inceptio

    Quantum Mechanics of Extended Objects

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    We propose a quantum mechanics of extended objects that accounts for the finite extent of a particle defined via its Compton wavelength. The Hilbert space representation theory of such a quantum mechanics is presented and this representation is used to demonstrate the quantization of spacetime. The quantum mechanics of extended objects is then applied to two paradigm examples, namely, the fuzzy (extended object) harmonic oscillator and the Yukawa potential. In the second example, we theoretically predict the phenomenological coupling constant of the ω\omega meson, which mediates the short range and repulsive nucleon force, as well as the repulsive core radius.Comment: RevTex, 24 pages, 1 eps and 5 ps figures, format change

    Unusual statistics of interference effects in neutron scattering from compound nuclei

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    We consider interference effects between p-wave resonance scattering amplitude and background s-wave amplitude in low-energy neutron scattering from a heavy nucleus which goes through the compound nucleus stage. The first effect is in the difference between the forward and backward scattering cross sections. Because of the chaotic nature of the compound states, this effect is a random variable with zero mean. However, a statistical consideration shows that the probability distribution of this effect does not obey the standard central limit theorem. That is, the probability density for the effect averaged over n resonances does not become a Gaussian distribution with the variance decreasing as 1/sqrt(n) (``violation'' of the theorem!). We derive the probability distribution of the effect and the limit distribution of the average. It is found that the width of this distribution does not decrease with the increase of n, i.e., fluctuations are not suppressed by averaging. Furthermore, we consider the correlation between the neutron spin and the scattering plane and find that this effect, although much smaller, shows fluctuations which actually increase upon averaging over many measurements. Limits of the effects due to finite resonance widths are also considered. In the appendix we present a simple derivation of the limit theorem for the average of random variables with infinite variances.Comment: 15 pages, RevTeX, submitted to Phys. Rev.
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