36,993 research outputs found

    Phase Coherence in Multiple Pulse Optical Spectroscopy

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    In this paper we describe a new technique for the generation of multiple pulse phase coherent sequences in optical spectroscopy. The technique is an extension of the acousto-optic modulation and fluorescence detection methods developed for optical transitions by Zewail and Orlowski (Zewail et al., Chem. Phys. Lett. 48, 256 (1977); Orlowski et al., Chem. Phys. Lett. 54, 197 (1978)). Application of these multiple pulse trains (of different phases) to optical transitions of two-level and multilevel systems is demonstrated experimentally. It is shown that they can be used to (i) suppress spontaneous emission background, (ii) enhance coherent transients such as photon echoes, (iii) measure additional relaxation parameters in systems with complex rotational-vibrational levels, and (iv) enhance the effective laser bandwidths through composite pulse trains, as demonstrated on I2 gas. Finally, the potential of this development is extended to the possibility of observing selective multiquantum excitation in molecules

    Studies of Impaired People in Paddock Wood

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    This volume contains three reports based on a community survey of impaired persons living in and around Paddock Wood, Kent and who were registered with a general medical practice of three partners working with nurses, health visitors and ancillary workers from a purpose-built health centre. The opportunity of working with a primary medical care team enabled a number of different questions to be examined, and because some of these form discrete areas of interest the results are presented in the following three papers:- Identifying Handicapped People in a General Practice Population. Interview Surveys of Handicapped People. The Accuracy of Statements about the Underlying Medical Conditions Handicapped People in Paddock Woo

    The Frontiers of Peer-to-Peer Lending: Thinking About a New Regulatory Approach

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    The growth of online alternative lending presents several advantages for both those seeking credit and those with excess capital to lend. Over the past decade, several different models of peer-to-peer lending have emerged in the US and U.K. Each of these models has developed in response to the different regulatory system it faces, which has led to the models’ different risk and reward profiles. However, the current regulatory framework for regulating peer-to-peer lending, especially in the U.S., leaves much to be desired. The inadequate regulatory regime not only hampers the potential for growth and further innovation in the industry, but also creates risks for consumers, lenders, and, as the sector grows, entire markets. There is no clear or easy answer as to the optimal regulatory regime, but regulators should at least consider the basic functions of peer-to-peer lending and how to address risks with a more comprehensive and sensible model for regulation

    1-Click Energy: Managing Corporate Demand for Clean Power

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    Globally, more private businesses, especially Fortune 100 companies are generating their own electricity, investing in renewable energy facilities, and voluntarily purchasing renewable energy credits to cover their carbon footprints. This shift could have a significant impact on the existing energy delivery system. On the one hand, this shift shows positive momentum toward the incorporation of clean energy into a fossil fuel dominated grid. As the negative impacts of climate change accelerate around the globe, decreasing reliance on fossil fuels is certainly an important goal. On the other hand, corporate disruption of what has historically been a highly regulated public service industry could result in a slippery slope of market power and loosened consumer protections, lost profits and stranded costs for utilities, and increased utility bills for the remaining customers. This Article recommends changes to the current regulatory scheme that would (1) go further to protect customers from multinational corporate wholesale sellers of electricity and (2) allow utilities to plan and collaborate earlier with large corporate customers to meet their clean energy demands

    2HOT: An Improved Parallel Hashed Oct-Tree N-Body Algorithm for Cosmological Simulation

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    We report on improvements made over the past two decades to our adaptive treecode N-body method (HOT). A mathematical and computational approach to the cosmological N-body problem is described, with performance and scalability measured up to 256k (2182^{18}) processors. We present error analysis and scientific application results from a series of more than ten 69 billion (409634096^3) particle cosmological simulations, accounting for 4×10204 \times 10^{20} floating point operations. These results include the first simulations using the new constraints on the standard model of cosmology from the Planck satellite. Our simulations set a new standard for accuracy and scientific throughput, while meeting or exceeding the computational efficiency of the latest generation of hybrid TreePM N-body methods.Comment: 12 pages, 8 figures, 77 references; To appear in Proceedings of SC '1

    Interning Ground Terms in XSB

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    This paper presents an implementation of interning of ground terms in the XSB Tabled Prolog system. This is related to the idea of hash-consing. I describe the concept of interning atoms and discuss the issues around interning ground structured terms, motivating why tabling Prolog systems may change the cost-benefit tradeoffs from those of traditional Prolog systems. I describe the details of the implementation of interning ground terms in the XSB Tabled Prolog System and show some of its performance properties. This implementation achieves the effects of that of Zhou and Have but is tuned for XSB's representations and is arguably simpler.Comment: Proceedings of the 13th International Colloquium on Implementation of Constraint LOgic Programming Systems (CICLOPS 2013), Istanbul, Turkey, August 25, 201