14,469 research outputs found

    The role of the N(2080)N^*(2080) resonance in the γpK+Λ(1520)\vec{\gamma} p \to K^+ \Lambda(1520) reaction

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    We investigate the Λ(1520)\Lambda(1520) photo-production in the γpK+Λ(1520)\vec{\gamma} p \to K^+ \Lambda(1520) reaction within the effective Lagrangian method near threshold. In addition to the "background" contributions from the contact, tt-channel KK exchange, and ss-channel nucleon pole terms, which were already considered in previous works, the contribution from the nucleon resonance N(2080)N^*(2080) (spin-parity JP=3/2J^P = 3/2^-) is also considered. We show that the inclusion of the nucleon resonance N(2080)N^*(2080) leads to a fairly good description of the new LEPS differential cross section data, and that these measurements can be used to determine some of the properties of this latter resonance. However, serious discrepancies appear when the predictions of the model are compared to the photon-beam asymmetry also measured by the LEPS Collaboration.Comment: 9 pages,6 figures, 1 tabl

    Subcentimeter depth resolution using a single-photon counting time-of-flight laser ranging system at 1550 nm wavelength

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    We demonstrate subcentimeter depth profiling at a stand off distance of 330m using a time-of-flight approach based on time-correlated single-photon counting. For the first time to our knowledge, the photon-counting time-of-flight technique was demonstrated at a wavelength of 1550nm using a superconducting nanowire single-photon detector. The performance achieved suggests that a system using superconducting detectors has the potential for low-light-level and eye-safe operation. The system’s instrumental response was 70ps full width at half-maximum, which meant that 1cm surface-to-surface resolution could be achieved by locating the centroids of each return signal. A depth resolution of 4mm was achieved by employing an optimized signal-processing algorithm based on a reversible jump Markov chain Monte Carlo method

    Getting Jobs, Keeping Jobs, and Earning a Living Wage: Can Welfare Reform Work?

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    Most discussions of welfare and work have focused on how demographic characteristics, schooling, training, and work experience limit welfare mothers’ employment and wages, but they have largely ignored factors such as inappropriate workplace behaviors, expectations of discrimination and harassment, depression, alcoholism, and domestic violence, all of which may affect welfare mothers and make employment difficult. In this paper we review the prevalence of these individual-level barriers and argue that they, in combination with an economy which does not pay low-skill workers well, are likely to impede employment and self-sufficiency for a large proportion of welfare mothers. At the end of the review, we summarize the current state of knowledge about barriers to the employment of welfare recipients and suggest several ways in which welfare-to-work programs might address these barriers.
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