10,006 research outputs found

    Economic structure, development policy and environmental quality : an empirical analysis of environmental Kuznets curves with Chinese municipal data

    Get PDF
    In many cases, the relationship between environmental pollution and economic development can be generally depicted by an inverted U-shaped curve, or an environmental Kuznets curve, where pollution increases with income at the beginning and decreases after a certain level of income. However, what determine the shape of an enviornmental Kuznets curve, such as the height and the turning point of the curve, have not been thoroughly studied. A good understanding of the determinants is vitally important to the development community, especially for the developing world, where income growth is a high priority and yet environmental pollution also needs to be carefully controlled. This study analyzes the impacts of economic structure, development strategy and environmental regulation on the shape of the environmental Kuznets curve with a city-level panel dataset obtained from China. The results show that economic structure, development strategy and environmental regulation can all have important implications on the relationship between environmental environmental quality and economic development but the impacts can be different at different development stages.Environmental Economics&Policies,Economic Theory&Research,Emerging Markets,Population Policies,Green Issues

    Complete Study of Hadroproduction of a Υ\Upsilon Meson Associated with a Prompt J/ψJ/\psi

    Full text link
    We present the first complete study of Υ\Upsilon and prompt J/ψJ/\psi production from single-parton scattering, including the complete O(αS6)\mathcal{O}(\alpha_S^6) color-singlet contribution, the O(αS2α2)\mathcal{O}(\alpha_S^2\alpha^2) electroweak contribution, the complete nonrelativistic S-wave and P-wave color-octet contribution as well as the feeddown contribution. Our study was motivated by the recent evidence reported by D0 Collaboration of prompt J/ψJ/\psi and Υ\Upsilon simultaneous production at the Tevatron. With our complete evaluation, we are able to refine the determination of the double parton scattering contribution made by D0 Collaboration. We find that the effective cross section characterizing the importance of double-parton scatterings is σeff8.2\sigma_{\rm eff}\le 8.2 mb at 68%68\% confidence level from the D0 measurement.Comment: 11 pages, 4 figures, 4 tables; v2: journal version, update the references and fix a few typo

    Segmentation of ultrasound images of thyroid nodule for assisting fine needle aspiration cytology

    Get PDF
    The incidence of thyroid nodule is very high and generally increases with the age. Thyroid nodule may presage the emergence of thyroid cancer. The thyroid nodule can be completely cured if detected early. Fine needle aspiration cytology is a recognized early diagnosis method of thyroid nodule. There are still some limitations in the fine needle aspiration cytology, and the ultrasound diagnosis of thyroid nodule has become the first choice for auxiliary examination of thyroid nodular disease. If we could combine medical imaging technology and fine needle aspiration cytology, the diagnostic rate of thyroid nodule would be improved significantly. The properties of ultrasound will degrade the image quality, which makes it difficult to recognize the edges for physicians. Image segmentation technique based on graph theory has become a research hotspot at present. Normalized cut (Ncut) is a representative one, which is suitable for segmentation of feature parts of medical image. However, how to solve the normalized cut has become a problem, which needs large memory capacity and heavy calculation of weight matrix. It always generates over segmentation or less segmentation which leads to inaccurate in the segmentation. The speckle noise in B ultrasound image of thyroid tumor makes the quality of the image deteriorate. In the light of this characteristic, we combine the anisotropic diffusion model with the normalized cut in this paper. After the enhancement of anisotropic diffusion model, it removes the noise in the B ultrasound image while preserves the important edges and local details. This reduces the amount of computation in constructing the weight matrix of the improved normalized cut and improves the accuracy of the final segmentation results. The feasibility of the method is proved by the experimental results.Comment: 15pages,13figure