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To examine the stability of prototypes of the kilogram after cleaning, surface analysis techniques, including X-ray photoelectron spectroscopy (XPS), were applied to specimens cut from prototype material of Pt-10 % Ir alloy. Traditional steam-jet cleaning (SJC) was compared with ultrasonic cleaning with solvents (UCS) in terms of cleaning effects and the progress of contamination. The results show that mass changes due to metallic factors such as oxidation, reduction and dissolution were negligibly small. In terms of carbon decrease and adsorption of water, UCS was superior to SJC. From analyses of peak area ratio by XPS, it was shown that the cleaner the surfaces, the higher the rate of contamination. But the contamination levels converged to a common value after a six-month exposure to air, irrespective of the cleaning method used. This finding is of great importance for the preservation of prototypes. The contaminating substances were found to be hydrocarbons from the ambient air. The mass gain for the surfaces of a prototype due to hydrocarbons after a six-month exposure to ambient air is estimated to be 4,3 pg for SJC and 16 pg for UCS.

This paper examines whether localized clusters of similar industries produce agglomeration economies in the formal and informal sectors. We develop a Bayesian method to estimate a spatial autoregressive model with an endogenous independent variable. We use establishment-level census data that cover both formal registered and informal unregistered establishments in Cambodia. We find that the density of local employment has a significantly positive effect on productivity in the informal sector, but little effect in the formal sector. For manufacturing, a doubling of employment density increases productivity in the informal sector by 9% through local linkages and by 17% through spatial multiplier linkages, leading to a 26% increase in total. A spatial network magnifies the local impact of agglomeration economies in the informal sector. The Institute of Developing Economies (IDE) is a semigovernmental, nonpartisan, nonprofit research institute, founded in 1958. The Institute merged with the Japan External Trade Organization (JETRO) on July 1, 1998. The Institute conducts basic and comprehensive studies on economic and related affairs in all developing countries and regions, including Asia, the

This paper estimates the impact of industrial agglomeration on firm-level productivity in Chinese manufacturing sectors. To account for spatial autocorrelation across regions, we formulate a hierarchical spatial model and use a Bayesian instrumental-variable approach. We find that agglomeration of the same industry (i.e., localization) has a productivity-boosting effect, but agglomeration of urban population (i.e., urbanization) has no such effect. In addition, the localization effect increases with the educational levels of employees and the share of intermediate inputs in gross output. These results may suggest that agglomeration externalities occur through knowledge spillovers and input sharing among firms producing similar manufactures.JEL classification: C21, C51, R10, R15 is a seminal work to present the general form of the hierarchical Bayesian regression. As for the details of the standard hierarchical Bayesian method, refer to Koop (2003), Gelman et al. (2004) and Lancaster (2004.3 While Smith and LeSage (2004) introduce a spatially dependent fixed effect into a Bayesian probit model, we employ a linear regression model with an endogenous regressor. As for the details of the Bayesian model with fixed (or individual) effects, refer to