37,934 research outputs found

    Raman spectroscopy with ultrashort coherent excitation. Narrowing of spectral lines beyond the dephasing linewidth

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    Spectroscopists are constantly faced with the task of improved spectral resolution. Two points are of major interest: (i) The precise frequency of the quantized transition and (ii) the detection of new neighboring transitions. Besides experimental factors the ultimate spectral resolution is determined by the inherent linewidth of the transition. Optical spectroscopists have to deal with different line-broadening processes; for instance with the Doppler effect or with collision broadening in gases, with dephasing processes in condensed systems and with the population relaxation which results in the natural linewidth. In recent years, different novel techniques have been devised which provide spectral resolution beyond the transition linewidth. For instance, Doppler broadening can be eliminated by saturation spectroscopy or by two counter-propagating beams for two-photon transitions/I/. Even measurements beyond the natural linewidth have been performed taking biased signals from the fluorescent decay /2-5/. Techniques have been proposed where the difference between the decay rates of the two states rather than their sum determines the linewidth /6,7/, and narrowing of the natural linewidth by decaying-pulse excitation has been discussed /8/. Very recently, we have demonstrated substantial line narrowing of Raman type transitions in condensed phases /9-11/. The lines were broadened by vibrational dephasing. New information was obtained in congestedspectral regions

    How Do Predatory Lending Laws Influence Mortgage Lending in Urban Areas? A Tale of Two Cities

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    This paper examines the effects of predatory lending laws in the cities of Chicago and Philadelphia. The level of mortgage activity in each of the cities is compared during the pre- and post-legislative periods relative to other parts of the state to assess the impact of localized legislation. In Chicago, where the predatory lending law focused on banks, a subprime origination in the city was found to be more likely to be made by a nonbank after the passage of the law. In Philadelphia, however, where the predatory legislation was aimed at all financial service providers, a decline was observed in the likelihood of a subprime loan being originated in the city during the post-legislation period, with the minority and low-income market segments experiencing the largest reduction.

    Experimental Potentials for the XΣ+2 and AΠ2 States of NaHe

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    Experimental potentials for the XΣ+2 and AΠ2 states of the NaHe molecule are presented. The potentials are generated from the temperature dependence of the red wing of the Na resonance line perturbed by He. For the AΠ2 state an unexpectedly large value is obtained for De=480(50) cm−1at Re=4.4(2)a0. The physical basis for this result, which indicates an important role for the internal structure of the rare gas in determining the repulsive part of the alkali-rare-gas interaction, is discussed

    Introduction to the themed issue - Corporate power : agency, communication, influence and social policy

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    This paper introduces this themed issue of Critical Social Policy on the question of corporate power. Corporate power is recognized as an important agent in social policy making and delivery. However, to date there has been comparatively little attention to the crucial role that lobbying and corporate 'spin' play in helping to shape policy making contexts. This special issue of Critical Social Policy is concerned to bring such issues to the mainstream of social policy analysis. It is argued here that the rise of spin and public relations is a key feature of neoliberalism in the past two decades. These have worked to reshape policy making, resulting in pronounced changes in the content and process of policy making and it is argued that these have tended to marginalize or undermine democratic processes
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