5,386 research outputs found

    Observation of blue-shifted ultralong-range Cs2_{2} Rydberg molecules

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    We observe ultralong-range blue-shifted Cs2_{2} molecular states near ns1/2ns_{1/2} Rydberg states in an optical dipole trap, where 31≤n≤3431\leq n\leq34. The accidental near degeneracy of (n−4)l(n-4)l and nsns Rydberg states for l>2l>2 in Cs, due to the small fractional nsns quantum defect, leads to non-adiabatic coupling among these states, producing potential wells above the nsns thresholds. Two important consequences of admixing high angular momentum states with nsns states are the formation of large permanent dipole moments, ∼15−100 \sim 15-100\,Debye, and accessibility of these states via two-photon association. The observed states are in excellent agreement with theory. Both projections of the total angular momentum on the internuclear axis are visible in the experiment

    Photoionization Rates of Cs Rydberg Atoms in a 1064 nm Far Off-Resonance Trap

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    Experimental measurements of photoionization rates of nD5/2nD_{5/2} Rydberg states of Cs (50≤n≤7550 \leq n \leq 75) in a 1064 nm far off-resonance dipole trap are presented. The photoionization rates are obtained by measuring the lifetimes of Rydberg atoms produced inside of a 1064 nm far off-resonance trap and comparing the lifetimes to corresponding control experiments in a magneto-optical trap. Experimental results for the control experiments agree with recent theoretical predictions for Rydberg state lifetimes and measured photoionization rates are in agreement with transition rates calculated from a model potential.Comment: 12 pages, 4 figure

    Three Proposals for Rewarding Novel Health Technologies Benefiting People Living in Poverty. A Comparative Analysis of Prize Funds, Health Impact Funds and a Cost-Effectiveness/Competitive Tender Treaty

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    This paper sets out to analyse three different academic proposals for addressing the needs of the poor in relation to new, rather than ‘essential’ medicines. It focuses particularly on (1) research and development (R&D) prize funds, (2) a health impact fund (HIF) system and (3) a multilateral treaty on health technology cost-effectiveness evaluation and competitive tender. It compares the extent to which each responds to the ‘market fundamentalist’ philosophy (that we maintain forms a loose theoretical background for the patent-driven approach to pharmaceutical R&D) and begins to analyse their respective strengths and weaknesses

    Unilateral and Exclusionary/Strategic Effects of Common Agency: Price Impacts in a Repeated Common Value English Auction

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    The business justification for multiple principals to hire a common agent is efficiency. Our empirical study demonstrates that the creation of the common agent unilaterally depresses winning bids. Additionally, the common agent was not only observed to be the dominant bidder but also paid significantly lower prices than fringe competitors (price/quantity differential). The observed price/quantity differential is consistent with the almost common value English auction theory developed by Rose and Kagel (2008) in which a cost advantaged bidder is able to reduce competition by credibly raising the costs of disadvantaged rivals associated with the winner’s curse.Common Value Auctions, Common Agency, Antitrust, Industrial Organization, D44, K21, K23,

    Lung Rest During Extracorporeal Membrane Oxygenation for Neonatal Respiratory Failure-Practice Variations and Outcomes.

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    OBJECTIVE: Describe practice variations in ventilator strategies used for lung rest during extracorporeal membrane oxygenation for respiratory failure in neonates, and assess the potential impact of various lung rest strategies on the duration of extracorporeal membrane oxygenation and the duration of mechanical ventilation after decannulation. DATA SOURCES: Retrospective cohort analysis from the Extracorporeal Life Support Organization registry database during the years 2008-2013. STUDY SELECTION: All extracorporeal membrane oxygenation runs for infants less than or equal to 30 days of life for pulmonary reasons were included. DATA EXTRACTION: Ventilator type and ventilator settings used for lung rest at 24 hours after extracorporeal membrane oxygenation initiation were obtained. DATA SYNTHESIS: A total of 3,040 cases met inclusion criteria. Conventional mechanical ventilation was used for lung rest in 88% of cases and high frequency ventilation was used in 12%. In the conventional mechanical ventilation group, 32% used positive end-expiratory pressure strategy of 4-6 cm H2O (low), 22% used 7-9 cm H2O (mid), and 43% used 10-12 cm H2O (high). High frequency ventilation was associated with an increased mean (SEM) hours of extracorporeal membrane oxygenation (150.2 [0.05] vs 125 [0.02]; p \u3c 0.001) and an increased mean (SEM) hours of mechanical ventilation after decannulation (135 [0.09] vs 100.2 [0.03]; p = 0.002), compared with conventional mechanical ventilation among survivors. Within the conventional mechanical ventilation group, use of higher positive end-expiratory pressure was associated with a decreased mean (SEM) hours of extracorporeal membrane oxygenation (high vs low: 136 [1.06] vs 156 [1.06], p = 0.001; mid vs low: 141 [1.06] vs 156 [1.06]; p = 0.04) but increased duration of mechanical ventilation after decannulation in the high positive end-expiratory pressure group compared with low positive end-expiratory pressure (p = 0.04) among survivors. CONCLUSIONS: Wide practice variation exists with regard to ventilator settings used for lung rest during neonatal respiratory extracorporeal membrane oxygenation. Use of high frequency ventilation when compared with conventional mechanical ventilation and use of low positive end-expiratory pressure strategy when compared with mid positive end-expiratory pressure and high positive end-expiratory pressure strategy is associated with longer duration of extracorporeal membrane oxygenation. Further research to provide evidence to drive optimization of pulmonary management during neonatal respiratory extracorporeal membrane oxygenation is warranted

    Safety, the Preface Paradox and Possible Worlds Semantics

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    This paper contains an argument to the effect that possible worlds semantics renders semantic knowledge impossible, no matter what ontological interpretation is given to possible worlds. The essential contention made is that possible worlds semantic knowledge is unsafe and this is shown by a parallel with the preface paradox
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