19,189 research outputs found

    Q^2 Evolution of the Neutron Spin Structure Moments using a ^3He Target

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    We have measured the spin structure functions g_1 and g_2 of ^3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized ^3He target at a 15.5° scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q^2 evolution of Γ_1(Q^2)=∫_0^1g_1(x,Q^2)dx, Γ_2(Q^2)=∫_0^1g_2(x,Q^2)dx, and d_2(Q^2)=∫_0^1x^2[2g_1(x,Q^2)+3g_2(x,Q^2)]dx for the neutron in the range 0.1 ≤ Q^2 ≤0.9  GeV^2 with good precision. Γ_1(Q^2) displays a smooth variation from high to low Q^2. The Burkhardt-Cottingham sum rule holds within uncertainties and d_2 is nonzero over the measured range

    Restructuring databases for knowledge discovery by consolidation and link formation

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    Databases often inaccurately identify entities of interest. Two operations, consolidation and link formation, which complement the usual machine learning techniques that use similarity-based clustering to discover classifications, are proposed as essential components of KDD systems for certain applications. Consolidation relates identifiers present in a database to a set of real world entities (RWE’s) which are not uniquely identified in the database. Consolidation may also be viewed as a transformation of representation from the identifiers present in the original database to the RWE’s. Link formation constructs structured relationships between consolidated RWE’s through identifiers and events explicitly represented in the database. Consolidation and link formation are easily implemented as index creation in relational database management systems. An operational knowledge discovery system identifies potential money laundering in a database of large cash transactions using consolidation and link formation

    Playware Explorations in Robot Art

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    Nuclear structure beyond the neutron drip line: the lowest energy states in 9^9He via their T=5/2 isobaric analogs in 9^9Li

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    The level structure of the very neutron rich and unbound 9^9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9^9He states exist with spins Jπ=1/2+J^\pi=1/2^+ and Jπ=1/2J^\pi=1/2^- and widths on the order of hundreds of keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8^8He+n+n system, performed via a search for the T=5/2 isobaric analog states in 9^9Li populated through 8^8He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad Jπ=1/2+J^{\pi}=1/2^+ state in 9^9He located approximately 3 MeV above the neutron decay threshold

    Effects of seawater and deionized water at 0 to 80 deg C on the flexural properties of a glass/epoxy composite

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    The effect on the flexural properties of a glass/epoxy composite of immersion in deionized water or seawater at 0, 25, and 80 C for 451 hr was examined. The percent weight gain at 0 and 25 C was low (0.06 to 0.17 percent) and there was no significant change in the flexural properties for these environmental conditions. At 80 C there was a decrease in the flexural strength of 17 and 20 percent in seawater and deionized water, respectively. This is a comparison to control samples exposed to 80 C heat alone. These decreases were found to be nearly reversible once the samples were dried. Optical microscopy did not reveal cracking of the matrix. The flexural modulus was essentially unaffected by exposure to deionized water and seawater at 80 C

    “Am I Telling the Story Right?” Poetry, Community, and Trauma

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    The Hill District of Pittsburgh, Pennsylvania (USA) is a once vibrant community that experienced socioeconomic decline through urban renewal polices and related factors. This article presents poems constructed from interviews with women who considered the Hill District to be their home. Interviews were completed as part of an undergraduate-level community-engaged learning course in collaboration with a local agency. One component of the course was a public reading, during which the poems were shared with members of the community and the University. The poems were created through use of the Listening Guide, a feminist relational method. These emotionally resonant poems, known as I poems, attend to the subjective experience of each participant by focusing on her use of “I” throughout the interview transcripts. While individual in nature, these poems are inseparable from the historical trauma the Hill District has experienced. Seen through the lens of root shock, interpersonal and intergenerational traumas are also the trauma of the Hill District. Poetic inquiry provides an avenue for connecting individual experience with the larger community story

    Shortest Path Computation with No Information Leakage

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    Shortest path computation is one of the most common queries in location-based services (LBSs). Although particularly useful, such queries raise serious privacy concerns. Exposing to a (potentially untrusted) LBS the client's position and her destination may reveal personal information, such as social habits, health condition, shopping preferences, lifestyle choices, etc. The only existing method for privacy-preserving shortest path computation follows the obfuscation paradigm; it prevents the LBS from inferring the source and destination of the query with a probability higher than a threshold. This implies, however, that the LBS still deduces some information (albeit not exact) about the client's location and her destination. In this paper we aim at strong privacy, where the adversary learns nothing about the shortest path query. We achieve this via established private information retrieval techniques, which we treat as black-box building blocks. Experiments on real, large-scale road networks assess the practicality of our schemes.Comment: VLDB201

    Statistics of Oscillator Strengths in Chaotic Systems

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    The statistical description of oscillator strengths for systems like hydrogen in a magnetic field is developed by using the supermatrix nonlinear σ\sigma-model. The correlator of oscillator strengths is found to have a universal parametric and frequency dependence, and its analytical expression is given. This universal expression applies to quantum chaotic systems with the same generality as Wigner-Dyson statistics.Comment: 11 pages, REVTeX3+epsf, two EPS figures. Replaced by the published version. Minor changes

    Structure of 10N in 9C+p resonance scattering

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    The structure of exotic nucleus 10N was studied using 9C+p resonance scattering. Two L=0 resonances were found to be the lowest states in 10N. The ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2) MeV depending on the 2- or 1- spin-parity assignment, and the first excited state is unbound by 2.8(2) MeV.Comment: 6 pages, 4 figures, 1 table, submitted to Phys. Lett.
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