992 resultados para Internal states
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We study a confined mixture of bosons and fermions in the quantal degeneracy regime with attractive boson-fermion interaction. We discuss the effect that the presence of vortical states and the displacement of the trapping potentials may have on mixtures near collapse, and investigate the phase stability diagram of the K-Rb mixture in the mean-field approximation supposing in one case that the trapping potentials felt by bosons and fermions are shifted from each other, as it happens in the presence of a gravitational sag, and in another case, assuming that the Bose condensate sustains a vortex state. In both cases, we have obtained an analytical expression for the fermion effective potential when the Bose condensate is in the Thomas-Fermi regime, that can be used to determine the maxima of the Fermionic density. We have numerically checked that the values one obtains for the location of these maxima using the analytical formulas remain valid up to the critical boson and fermion numbers, above which the mixture collapses.
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We study strongly correlated ground and excited states of rotating quasi-2D Fermi gases constituted of a small number of dipole-dipole interacting particles with dipole moments polarized perpendicular to the plane of motion. As the number of atoms grows, the system enters an intermediate regime, where ground states are subject to a competition between distinct bulk-edge configurations. This effect obscures their description in terms of composite fermions and leads to the appearance of novel quasihole ground states. In the presence of dipolar interactions, the principal Laughlin state at filling upsilon=1/3 exhibits a substantial energy gap for neutral (total angular momentum conserving) excitations and is well-described as an incompressible Fermi liquid. Instead, at lower fillings, the ground state structure favors crystalline order.
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The monopole (L=0) and quadrupole (L=2) strength distributions in normal 3He clusters are calculated within the random-phase approximation. We use a phenomenological, zero-range 3-3He interaction to generate the Hartree-Fock single-particle spectrum and the residual particle-hole interaction. The evolution of the collective modes with the number of atoms in the cluster is discussed.
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We illustrate how to apply modern effective field-theory techniques and dimensional regularization to factorize the various scales, which appear in QED bound states at finite temperature. We focus here on the muonic hydrogen atom. Vacuum polarization effects make the physics of this atom at finite temperature very close to that of heavy quarkonium states. We comment on the implications of our results for these states in the quark gluon plasma. In particular, we estimate the effects of a finite-charm quark mass in the dissociation temperature of bottomonium.
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We present the relationship between nonlinear-relaxation-time (NLRT) and quasideterministic approaches to characterize the decay of an unstable state. The universal character of the NLRT is established. The theoretical results are applied to study the dynamical relaxation of the Landau model in one and n variables and also a laser model.
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Audit report on Internal Control over Financial Reporting of the State University of Iowa as of and for the year ended June 30, 2011
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Independent auditor’s report of the State of Iowa on internal control over financial reporting and on compliance and other matters based on an audit of financial statements performed in accordance with government auditing standards for the year ended June 30, 2011
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Starting from a recent model of the η′N interaction, we evaluate the η ′-nucleus optical potential, including the contribution of lowest order in density, tρ/2mη′, together with the second-order terms accounting for η′ absorption by two nucleons. We also calculate the formation cross section of the η′bound states from (π, p) reactions on nuclei. The η′-nucleus potential suffers from uncertainties tied to the poorly known η′N interaction, which can be partially constrained by the experimental modulus of the η′N scattering length and/or the recently measured transparency ratios in η′nuclear photoproduction. Assuming an attractive interaction and taking the claimed experimental value |aη′N|= 0.1 fm, we obtain an η′optical potential in nuclear matter at saturation density of Vη′=−(8.7 + 1.8i) MeV, not attractive enough to produce η′bound states in light nuclei. Larger values of the scattering length give rise to deeper optical potentials, with moderate enough imaginary parts. For a value |aη′N|= 0.3 fm, which can still be considered to lie within the uncertainties of the experimental constraints, the spectra of light and medium nuclei show clear structures associated to η′-nuclear bound states and to threshold enhancements in the unbound region.
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The fou8 loss of function allele of adenosine bisphosphate phosphatase FIERY1 results in numerous phenotypes including the increased enzymatic oxygenation of fatty acids and increased jasmonate synthesis. Here we show that the mutation causes also profound alterations of sulfur metabolism. The fou8 mutants possess lower levels of sulfated secondary compounds, glucosinolates, and accumulate the desulfo-precursors similar to previously described mutants in adenosine 5'phosphosulfate kinase. Transcript levels of genes involved in sulfate assimilation differ in fou8 compared to wild type Col-0 plants and are similar to plants subjected to sulfate deficiency. Indeed, independent microarray analyses of various alleles of mutants in FIERY1 showed similar patterns of gene expression as in sulfate deficient plants. This was not caused by alterations in signalling, as the fou8 mutants contained significantly lower levels of sulfate and glutathione and, consequently, of total elemental sulfur. Analysis of mutants with altered levels of sulfate and glutathione confirmed the correlation of sulfate deficiency-like gene expression pattern with low internal sulfate but not low glutathione. The changes in sulfur metabolism in fou8 correlated with massive increases in 3'-phosphoadenosine 5'-phosphate levels. The analysis of fou8 thus revealed that sulfate starvation response is triggered by a decrease in internal sulfate as opposed to external sulfate availability and that the presence of desulfo-glucosinolates does not induce the glucosinolate synthesis network. However, as well as resolving these important questions on the regulation of sulfate assimilation in plants, fou8 has also opened an array of new questions on the links between jasmonate synthesis and sulfur metabolism.
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BACKGROUND: Influenza vaccination remains below the federally targeted levels outlined in Healthy People 2020. Compared to non-Hispanic whites, racial and ethnic minorities are less likely to be vaccinated for influenza, despite being at increased risk for influenza-related complications and death. Also, vaccinated minorities are more likely to receive influenza vaccinations in office-based settings and less likely to use non-medical vaccination locations compared to non-Hispanic white vaccine users. OBJECTIVE: To assess the number of "missed opportunities" for influenza vaccination in office-based settings by race and ethnicity and the magnitude of potential vaccine uptake and reductions in racial and ethnic disparities in influenza vaccination if these "missed opportunities" were eliminated. DESIGN: National cross-sectional Internet survey administered between March 4 and March 14, 2010 in the United States. PARTICIPANTS: Non-Hispanic black, Hispanic and non-Hispanic white adults living in the United States (N = 3,418). MAIN MEASURES: We collected data on influenza vaccination, frequency and timing of healthcare visits, and self-reported compliance with a potential provider recommendation for vaccination during the 2009-2010 influenza season. "Missed opportunities" for seasonal influenza vaccination in office-based settings were defined as the number of unvaccinated respondents who reported at least one healthcare visit in the Fall and Winter of 2009-2010 and indicated their willingness to get vaccinated if a healthcare provider strongly recommended it. "Potential vaccine uptake" was defined as the sum of actual vaccine uptake and "missed opportunities." KEY RESULTS: The frequency of "missed opportunities" for influenza vaccination in office-based settings was significantly higher among racial and ethnic minorities than non-Hispanic whites. Eliminating these "missed opportunities" could have cut racial and ethnic disparities in influenza vaccination by roughly one half. CONCLUSIONS: Improved office-based practices regarding influenza vaccination could significantly impact Healthy People 2020 goals by increasing influenza vaccine uptake and reducing corresponding racial and ethnic disparities.
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This paper deals with the determination of the interface density of states in amorphous silicon-based multilayers. Photothermal deflection spectroscopy is used to characterize two series of aSi:H/aSi1-xCx:H multilayers, and a new approach in the treatment of experimental dada is used in order to obtain accurate results. From this approach, an upper limit of 10^10 cm-2 is determined for the interface density of states.
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The issue of de Sitter invariance for a massless minimally coupled scalar field is examined. Formally, it is possible to construct a de Sitterinvariant state for this case provided that the zero mode of the field is quantized properly. Here we take the point of view that this state is physically acceptable, in the sense that physical observables can be computed and have a reasonable interpretation. In particular, we use this vacuum to derive a new result: that the squared difference between the field at two points along a geodesic observers spacetime path grows linearly with the observers proper time for a quantum state that does not break de Sitter invariance. Also, we use the Hadamard formalism to compute the renormalized expectation value of the energy-momentum tensor, both in the O(4)-invariant states introduced by Allen and Follaci, and in the de Sitterinvariant vacuum. We find that the vacuum energy density in the O(4)-invariant case is larger than in the de Sitterinvariant case.
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region to the other. We also present a C-type solution that describes neutral bubbles in uniform acceleration, and we use it to construct an instanton that mediates the breaking of a cosmic string by forming bubbles at its ends. The rate for this process is also calculated. Finally, we argue that a similar solution can be constructed for magnetic bubbles, and that it can be used to describe a semiclassical instability of the two-timing vacuum against production of massless monopole pairs.
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The evaluation’s overarching question was “Did the activities undertaken through the state’s LSTA plan achieve results related to priorities identified in the Act?” The evaluation was conducted and is organized according to the six LSTA priorities. The research design employed two major methodologies: 1. Data sources from Iowa Library Services / State Library of Iowa2 as well as U.S and state sources were indentified for quantitative analysis. These sources, which primarily reflect outputs for various projects, included: Statistics from the Public Library Annual Survey Statistics collected internally by Iowa Library Services such as number of libraries subscribing to sponsored databases, number of database searches, attendance at continuing education events, number of interlibrary loan transactions Evaluation surveys from library training sessions, professional development workshops and other programs supported by LSTA funds Internal databases maintained by Iowa Library Services Impact results from post training evaluations conducted by Iowa Library Services 2010 Iowa census data from the U.S. Census Bureau LSTA State Program Reports for the grant period 2. Following the quantitative analysis, the evaluator gathered qualitative data through interviews with key employees, a telephone focus group with district library consultants and two surveys: LSTA Evaluation Survey (Public Libraries) and LSTA Evaluation Survey (Academic Libraries). Both surveys provided sound samples with 43 representatives of Iowa’s 77 academic libraries and 371 representatives of Iowa’s 544 public libraries participating. Respondents represented libraries of all sizes and geographical areas. Both surveys included multiple choice and rating scale items as well as open-ended questions from which results were coded to identify trends, issues and recommendations.