Examination and Interpretation of the Quantitative Validity in China’s Corporate-based Urban Network Analysis

As a matter of expediency, most existing corporate-based urban networks can only be quantitatively measured by either counting the number of linkages or calculating the product of estimated service values. However, the impreciseness arising due to the limits of quantitative analysis may prove fatal to studies about non-market economies like China. Employing the capital investment dataset as an example, we build a capital-weighted intervention network as well as an unweighted control network to carry out an examination of the quantitative validity in China’s corporate-based urban network analysis. Both the overall spatial pattern and top city-dyads within the capital-weighted network witness Beijing, as the most dominant city, overshadow the performance of the others, and the unweighted network shows multilateral interactions between China’s top cities including Beijing, Shanghai, Shenzhen, and Guangzhou. To further interpret the noticeable differences, we divide the overall network into two subnetworks, inferred by focusing on state-owned enterprises(SOEs) and private enterprises. The results show that the public and private sectors have separately created vastly different subnetworks in China and that SOEs play a much more significant role in terms of capital. Besides fresh insights into China’s urban network, this study provides a cautionary tale reminding researchers of the essentiality and complexity when making a quantitative distinction between different linkages.

A new method for validation of quantitative measurement by intravascular ultrasound in vivo

Studies in vitro show that intravascular ultrasound (IVUS) underestimates vessel and lumen dimensions. In order to validate IVUS measurement in vivo, we conducted a comparative study during catheterization in fifty patients. The patients underwent IVUS examinations for the purpose of diagnosis or treatment of coronary artery disease. The IVUS system was a 3.5 F, 20 MHz IVUS catheter (Sonicath catheter of Boston Scientific Co.) and a Hewlett Packard console. After examination of the coronary artery, the IVUS probe was withdrawn back into the guiding catheter to measure the average lumen diameter of the guiding catheter (8 F, Cordis). This measurement in vivo (VI) was compared with the true lumen diameter provided by the manufac Department of Cardiology, University of Essen, Essen, Germany (Liu FQ, Ge JB, Baumgart D, Haude M, Caspari G, Grge G, Eick B and Erbel R) turer (MA) and determined by on line quantitative angiography (HICOR, Siemens) (HI). In addition, the IVUS measurement in vitro (VT) was also taken with the same guiding catheter in waterbath at 37℃. The results showed that IVUS underestimated the true lumen diameter by 2.2%±2.6% in vivo, by 3.1%±1.8% in vitro, while HICOR owerestimated the true lumen diameter by 23.0%±6.8%. There was no difference between the IVUS measurements in vivo and in vitro. In summary, IVUS was very accurate for the measurement of a 8 F guiding catheter in vivo with only a minor underestimation, and IVUS measurement was far more reliable than the on line quantitative angiography.