1,315 research outputs found

    Joe Orton: A High Comedy of Bad Manners

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    Uncertainty, Risk and Investment Decisions

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    Many government-sponsored applied research, development, demonstration and incentive programs are specifically undertaken to develop technology or create an environment that will lead to commercial ventures which will be in the public interest. The current Administration\u27s emphasis on commercialization has brought to the forefront joint endeavor or government/industry cooperative agreements and proposals for divesting operational capabilities to the private sector. The common thread between all these activities is the need for government agencies to plan and evaluate the private sector business ventures that may result. In the case of the joint endeavor agreements and divestiture situations, the evaluation of private sector business ventures is necessary to establish government negotiating positions. This paper briefly summarizes private sector financial performance measures and shows how government actions can affect private sector investment decisions through a reduction in perceived risk and shifting the burden of funding from the private sector to the public sector. Data is presented that illustrates the functional relationship betwen likelihood of investment and expected return on investment, risk, payback period and exposure. Finally, the required public sector financial analysis in support of joint endeavor agreements and divestiture situations is examined. Many questions and issues are raised with general procedures developed to answer a number of these

    Transient dynamics and momentum redistribution in cold atoms via recoil-induced resonances

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    We use an optically dense, anisotropic magneto-optical trap to study recoil-induced resonances (RIRs) in the transient, high-gain regime. We find that two distinct mechanisms govern the atomic dynamics: the finite, frequency-dependent atomic response time, and momentum-space population redistribution. At low input probe intensities, the residual Doppler width of the atoms, combined with the finite atomic response time, result in a linear, transient hysteretic effect that modifies the locations, widths, and magnitudes of the resulting gain spectra depending on the sign of the scan chirp. When larger intensities (\textit{i.e.}, greater than a few μ\muW/cm2^2) are incident on the atomic sample for several μ\mus, hole-burning in the atomic sample's momentum distribution leads to a coherent population redistribution that persists for approximately 100 μ\mus. We propose using RIRs to engineer the atomic momentum distribution to enhance the nonlinear atom-photon coupling. We present a numerical model, and compare the calculated and experimental results to verify our interpretation.Comment: 7 pages, 6 figure

    Can Power from Space Compete?

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    Satellite solar power (SSP) has been suggested as an alternative to terrestrial energy resources for electricity generation. In this study, we consider the market for electricity from the present to 2020, roughly the year when many experts expect SSP to be technically achievable. We identify several key challenges for SSP in competing with conventional electricity generation in developed and developing countries, discuss the role of market and economic analysis as technical development of SSP continues during the coming years, and suggest future research directions to improve understanding of the potential economic viability of SSP.

    Paper Session II-B - The Selection of a Launch Vehicle

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    The selection of a launch vehicle should not depend on any single vehicle attribute (i.e., price, reliability, availability, insurance rate, final payload placement accuracy, etc.), but rather on the effect of the interaction of multiple vehicle attributes in combination with payload configuration and sparing/maintenance strategy. For commercial organizations, selection decisions should be based on performance measures such as ROI and risk. For government operations, selections should be based on measures such as present value of life cycle cost in combination with availability constraints. Methods for analyzing launch vehicle and related choices are described together with parametric results illustrating important tradeoffs

    Euclidean Traveling Salesman Heuristics

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    High-order optical nonlinearity at low light levels

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    We observe a nonlinear optical process in a gas of cold atoms that simultaneously displays the largest reported fifth-order nonlinear susceptibility \chi^(5) = 1.9x10^{-12} (m/V)^4 and high transparency. The nonlinearity results from the simultaneous cooling and crystallization of the gas, and gives rise to efficient Bragg scattering in the form of six-wave-mixing at low-light-levels. For large atom-photon coupling strengths, the back-action of the scattered fields influences the light-matter dynamics. This system may have important applications in many-body physics, quantum information processing, and multidimensional soliton formation.Comment: 5 pages, 3 figure

    Regional differences in the coupling between resting cerebral blood flow and metabolism may indicate action preparedness as a default state.

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    Although most functional neuroimaging studies examine task effects, interest intensifies in the "default" resting brain. Resting conditions show consistent regional activity, yet oxygen extraction fraction constancy across regions. We compared resting cerebral metabolic rates of glucose (CMRgl) measured with 18F-labeled 2-fluoro-2-deoxy-D-glucose to cerebral blood flow (CBF) 15O-H2O measures, using the same positron emission tomography scanner in 2 samples (n = 60 and 30) of healthy right-handed adults. Region to whole-brain ratios were calculated for 35 standard regions of interest, and compared between CBF and CMRgl to determine perfusion relative to metabolism. Primary visual and auditory areas showed coupling between CBF and CMRgl, limbic and subcortical regions--basal ganglia, thalamus and posterior fossa structures--were hyperperfused, whereas association cortices were hypoperfused. Hyperperfusion was higher in left than right hemisphere for most cortical and subcallosal limbic regions, but symmetric in cingulate, basal ganglia and somatomotor regions. Hyperperfused regions are perhaps those where activation is anticipated at short notice, whereas downstream cortical modulatory regions have longer "lead times" for deployment. The novel observation of systematic uncoupling of CBF and CMRgl may help elucidate the potential biological significance of the "default" resting state. Whether greater left hemispheric hyperperfusion reflects lateral dominance needs further examination
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