10,229 research outputs found

    Fast beam stacking using RF barriers

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    Two barrier RF systems were fabricated, tested and installed in the Fermilab Main Injector. Each can provide 8 kV rectangular pulses (the RF barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector, which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology.Comment: 2007 Particle Accelerator Conference (PAC07

    Dollarizing The Cash Conversion Cycle

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    For most companies to be financially successful, it is critically important that operating cash flows be effectively managed. The Cash Conversion Cycle (CCC) is a traditional tool that companies use to measure the average time required for operating cash flows to cycle from cash out for the payment of payables and back to cash flow in from the collection of receivables. Knowledge that the rate their operating cash flow is speeding up or slowing down, as indicated by a decreasing or increasing CCC, while useful information, is of limited value to the company. The CCC indicates nothing about the absolute dollar amount of the cash flow. This paper illustrates a method by which the current year actual CCC and the next year target CCC, along with a few other items of data, can be used to forecast the dollar amount of the next year’s operating cash flows. The extension of the CCC to enable it to help forecast the dollar amount of operating cash flows makes the CCC more useful to companies attempting to effectively manage operating cash flows

    Deviations from ozone photostationary state during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign: Use of measurements and photochemical modeling to assess potential causes

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    Nitric oxide (NO) and nitrogen dioxide (NO2) were monitored at the University of New Hampshire Atmospheric Observing Station at Thompson Farm (TF) during the ICARTT campaign of summer 2004. Simultaneous measurement of ozone (O3), temperature, and the photolysis rate of NO2 (jNO2) allow for assessment of the O3 photostationary state (Leighton ratio, Φ). Leighton ratios that are significantly greater than unity indicate that peroxy radicals (PO2), halogen monoxides, nitrate radicals, or some unidentified species convert NO to NO2 in excess of the reaction between NO and O3. Deviations from photostationary state occurred regularly at TF (1.0 ≤ Φ ≤ 5.9), particularly during times of low NOx (NOx = NO + NO2). Such deviations were not controlled by dynamics, as indicated by regressions between Φ and several meteorological parameters. Correlation with jNO2 was moderate, indicating that sunlight probably controls nonlinear processes that affect Φ values. Formation of PO2 likely is dominated by oxidation of biogenic hydrocarbons, particularly isoprene, the emission of which is driven by photosynthetically active radiation. Halogen atoms are believed to form via photolysis of halogenated methane compounds. Nitrate radicals are believed to be insignificant. Higher Φ values are associated with lower mixing ratios of isoprene and chloroiodomethane and lower ratios of NOx to total active nitrogen, indicating that photochemical aging may very well lead to increased Φ values. PO2 levels calculated using a zero‐dimensional model constrained by measurements from TF can account for 71% of the observed deviations on average. The remainder is assumed to be associated with halogen atoms, most likely iodine, with necessary mixing ratios up to 0.6 or 1.2 pptv, for chlorine and iodine, respectively

    Systematic review of the current status of cadaveric simulation for surgical training

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    Background: There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training. Methods: A PRISMA‐compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool. Results: A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7). Conclusion: There is an abundance of relatively low‐quality evidence showing that cadaveric simulation induces short‐term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre

    U.S. Marine Corps Equipment Readiness Information Tool: usage and decision-support for performance based logistics

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    MBA Professional ReportThe Marine Corps is transforming its automated logistics programs to meet the increasingly complex operational requirements of the 21st Century. One program that is part of this transformation is the Marine Corps Equipment Readiness Information Tool (MERIT). Our research analyzed: how can MERIT be used as a decision support tool for performance based logistics (PBL) and what areas of MERIT are recommended for improvement. Included in the analysis is a description of current readiness procedures used in the Marine Corps, providing a point of comparison for how well MERIT enables the logistics transformation. The basis of our analysis was user perceptions, assessed by a user survey and focus groups. The conclusions of our analysis determined: MERIT has not received official Marine Corps endorsement for its continued use; MERIT is a valuable material readiness information tool used by the Marine Corps; there is a general lack of understanding by users regarding MERIT's logical architecture and operation; and there is a lack of training on MERIT throughout the Marine Corps.http://archive.org/details/usmarinecorpsequ109459891Major, United States Marine CorpsCaptain, United States Marine CorpsApproved for public release; distribution is unlimited

    Surface Contribution to Raman Scattering from Layered Superconductors

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    Generalizing recent work, the Raman scattering intensity from a semi-infinite superconducting superlattice is calculated taking into account the surface contribution to the density response functions. Our work makes use of the formalism of Jain and Allen developed for normal superlattices. The surface contributions are shown to strongly modify the bulk contribution to the Raman-spectrum line shape below 2Δ2\Delta, and also may give rise to additional surface plasmon modes above 2Δ2\Delta. The interplay between the bulk and surface contribution is strongly dependent on the momentum transfer qq_\parallel parallel to layers. However, we argue that the scattering cross-section for the out-of-phase phase modes (which arise from interlayer Cooper pair tunneling) will not be affected and thus should be the only structure exhibited in the Raman spectrum below 2Δ2\Delta for relatively large q0.1Δ/vFq_\parallel\sim 0.1\Delta/v_F. The intensity is small but perhaps observable.Comment: 14 pages, RevTex, 6 figure

    Two-fluid dynamics for a Bose-Einstein condensate out of local equilibrium with the non-condensate

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    We extend our recent work on the two-fluid hydrodynamics of a Bose-condensed gas by including collisions involving both condensate and non-condensate atoms. These collisions are essential for establishing a state of local thermodynamic equilibrium between the condensate and non-condensate. Our theory is more general than the usual Landau two-fluid theory, to which it reduces in the appropriate limit, in that it allows one to describe situations in which a state of complete local equilibrium between the two components has not been reached. The exchange of atoms between the condensate and non-condensate is associated with a new relaxational mode of the gas.Comment: 4 pages, revtex, 1 postscript figure, Fig.1 has been correcte

    Anisotropy in the Cosmic Microwave Background at Degree Angular Scales: Python V Results

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    Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m off-axis telescope instrumented with a HEMT amplifier-based radiometer having continuum sensitivity from 37-45 GHz in two frequency bands. With a 0.91 deg x 1.02 deg beam the instrument fully sampled 598 deg^2 of sky, including fields measured during the previous four seasons of Python observations. Interpreting the observed fluctuations as anisotropy in the cosmic microwave background, we place constraints on the angular power spectrum of fluctuations in eight multipole bands up to l ~ 260. The observed spectrum is consistent with both the COBE experiment and previous Python results. There is no significant contamination from known foregrounds. The results show a discernible rise in the angular power spectrum from large (l ~ 40) to small (l ~ 200) angular scales. The shape of the observed power spectrum is not a simple linear rise but has a sharply increasing slope starting at l ~ 150.Comment: 5 page
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