1,044 research outputs found

    Comment: Citation Statistics

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    We discuss the paper "Citation Statistics" by the Joint Committee on Quantitative Assessment of Research [arXiv:0910.3529]. In particular, we focus on a necessary feature of "good" measures for ranking scientific authors: that good measures must able to accurately distinguish between authors.Comment: Published in at http://dx.doi.org/10.1214/09-STS285B the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    PHYTOSANITARY REGULATION AND AGRICULTURAL FLOWS: TOBACCO INPUTS AND CIGARETTES OUTPUTS

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    This paper examines the effects of the use of increasingly-popular phytosanitary regulations on production costs, and output and factor trade flows. The case addressed is that of the European regulation of maximum chemical residues in cigarettes manufactured with tobacco containing maleic hydrazide. The paper presents simulations of the effects of tightening the input/output market linkages and on the substitution away from the residue-contaminated U.S. input to residue-free non-U.S. inputs. This induced substitution results in higher costs, lower quantity supplied of the final product, and higher prices for U.S. cigarettes in Europe. Cross-price effects lead to higher quantities of EU cigarettes sold and a corresponding increase in the use of all inputs, including U.S. tobacco. When the U.S. tobacco price is allowed to fall, direct price effects stimulate the EU derived demand for U.S. tobacco. Although the regulation is protectionist in the output market, it leads to increased EU imports of the residue-contaminated input. When the price of U.S. tobacco adjusts, the regulation is actually antiprotective for EU growers. The regulation also indirectly influences production practices of U.S. tobacco growers and leads to lower levels of MH residues on U.S. leaf.Agricultural and Food Policy,

    Two-photon- photoluminescence excitation spectroscopy of single quantum-dots

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    We present experimental and theoretical study of single semiconductor quantum dots excited by two non-degenerate, resonantly tuned variably polarized lasers. The first laser is tuned to excitonic resonances. Depending on its polarization it photogenerates a coherent single exciton state. The second laser is tuned to biexciton resonances. By scanning the energy of the second laser for various polarizations of the two lasers, while monitoring the emission from the biexciton and exciton spectral lines, we map the biexciton photoluminescence excitation spectra. The resonances rich spectra of the second photon absorption are analyzed and fully understood in terms of a many carrier theoretical model which takes into account the direct and exchange Coulomb interactions between the quantum confined carriers.Comment: Accepted for publication in PR

    Polarization memory in single Quantum Dots

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    We measured the polarization memory of excitonic and biexcitonic optical transitions from single quantum dots at either positive, negative or neutral charge states. Positive, negative and no circular or linear polarization memory was observed for various spectral lines, under the same quasi-resonant excitation below the wetting layer band-gap. We developed a model which explains both qualitatively and quantitatively the experimentally measured polarization spectrum for all these optical transitions. We consider quite generally the loss of spin orientation of the photogenerated electron-hole pair during their relaxation towards the many-carrier ground states. Our analysis unambiguously demonstrates that while electrons maintain their initial spin polarization to a large degree, holes completely dephase.Comment: 6 pages, 4 figure

    The Medical Waste Management in Health Centers as the City of Pekanbaru

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    The amount of medical waste comes from health facilities are expected more increasing. Based on Indonesia Health Profile 2008, amount of health centers reached 8,548 units. Management of medical waste from hospitals, health centers, clinics and medical laboratories in Indonesia is still under professional standards. In Pekanbaru city does not have accurate data on medical waste management in health centers, and therefore it necessary related research to see the extent of medical waste management health centers. This study aims to determine the medical waste management in health centers as the city of Pekanbaru. Type of research is descriptive qualitative, study was conducted in 20 health centers in Pekanbaru. The number of informants in this study were 21 people consisting of 20 holders of environmental health programs each health center and 1 holder of the environmental sanitation program at the City Health Office. Instrument research using in-depth interviews and observation sheets. Results reveal that a health center of Pekanbaru city has done a medical waste management ranging from segregation, collection, storage, transportation, yet at the stage of annihilation still less than the maximum. Constraints faced was funding the operation and maintenance personnel as well as there is no incinerator machine is not functioning properl

    Hjernen i computeren: Computeren i hjernen

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    Updated version of final design and of the architecture of SEAMLESS-IF

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    Agricultural and Food Policy, Environmental Economics and Policy, Farm Management, Land Economics/Use, Livestock Production/Industries,
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