How vertically specialized is Chinese trade?

Two recent phenomena have transformed the nature of world trade: the explosive growth of Chinese trade, and the growth of vertically specialized trade due to international production fragmentation. While vertical specialization may explain much of the growth and unique features of Chinese trade, few papers have quantitatively assessed these two phenomena together. In part, this is because it is difficult to measure just how vertically specialized Chinese trade is. The unique features of China's extensive processing trade cause both the identification of imported intermediate goods, and their allocation across sectors, to depend upon the Chinese trade regime. In this paper, we estimate the vertical specialization of Chinese exports, addressing these two challenges. Using two Chinese benchmark input-output tables, and a detailed Chinese trade dataset which distinguishes processing trade from other forms of trade, we develop a new method of identifying intermediate goods imported into China. Vertical specialization is then estimated using two methods. The first method uses the Hummels, Ishii and Yi (2001) measure, the official benchmark IO tables, and incorporates our identification correction. The second method follows the first, but also incorporates the Koopman, Wang and Wei (2008) method of splitting the benchmark IO tables into separate tables for processing and normal exports, in order to address the allocation problem. Results show strong evidence of an Asian network of intermediate suppliers to China, and the two methods provide a range of estimates for the foreign content of Chinese exports. In 2002 aggregate exports ranges between 25% and 46%, with some individual sectors are as high as 52%-95%. Across destinations, under both methods, the vertical specialization of Chinese exports declines with the level of development of the trading partner.China; fragmentation; vertical specialization; trade growth

Co-ordinating retinal histogenesis: early cell cycle exit enhances early cell fate determination in the Xenopus retina

The laminar arrays of distinct cell types in the vertebrate retina are built by a histogenic process in which cell fate is correlated with birth order. To explore this co-ordination mechanistically, we altered the relative timing of cell cycle exit in the developing Xenopus retina and asked whether this affected the activity of neural determinants. We found that Xath5, a bHLH proneural gene that promotes retinal ganglion cell (RGC) fate, ( Kanekar, S., Perron, M., Dorsky, R., Harris, W. A., Jan, L. Y., Jan, Y. N. and Vetter, M. L. (1997) Neuron 19, 981-994), does not cause these cells to be born prematurely. To drive cells out of the cell cycle early, therefore, we misexpressed the cyclin kinase inhibitor, p27Xic1. We found that early cell cycle exit potentiates the ability of Xath5 to promote RGC fate. Conversely, the cell cycle activator, cyclin E1, which inhibits cell cycle exit, biases Xath5-expressing cells toward later neuronal fates. We found that Notch activation in this system caused cells to exit the cell cycle prematuely, and when it is misexpressed with Xath5, it also potentiates the induction of RGCs. The potentiation is counteracted by co-expression of cyclin E1. These results suggest a model of histogenesis in which the activity of factors that promote early cell cycle exit enhances the activity of factors that promote early cellular fates

Monopole Percolation and The Universality Class of the Chiral Transition in Four Flavor Noncompact Lattice QED

We simulate four flavor noncompact lattice QED using the Hybrid Monte Carlo algorithm on $10^4$ and $16^4$ lattices. Measurements of the monopole susceptibility and the percolation order parameter indicate a transition at $\beta = {1/e^2} = .205(5)$ with critical behavior in the universality class of four dimensional percolation. We present accurate chiral condensate measurements and monitor finite size effects carefully. The chiral condensate data supports the existence of a power-law transition at $\beta = .205$ in the same universality class as the chiral transition in the two flavor model. The resulting equation of state predicts the mass ratio $m_\pi^2/m_\sigma^2$ in good agreement with spectrum calculations while the hypothesis of a logarithmically improved mean field theory fails qualitatively.Comment: 17 pages, 10 figure

A Three-Dimensional Position Architecture Using Digital TDE Receiver and Cylindrical Array Antenna

AbstractThe robust three-dimensional position architecture is proposed in the paper, where the hybrid time difference of arrival (TDOA) and direction of arrival (DOA) position system was designed to backup the four-station TDOA position system. The digital time delay estimation (TDE) receiver is used for TDOA measurement and the cylindrical array antenna is used for DOA measurement. The general formula of linear phase compensation for cylindrical array antenna in horizontal plane is derived. The detection probability of the TDE receiver and the circular error probability (CEP) of the position systems over Rayleigh fading channel were numerically computed in three-dimensional space. Simulations indicate that the position accuracy of the four-station TDOA position system is degraded but the location function can be retained by the hybrid TDOA and DOA position system when any one of four-stations is out of work

Probabilistic Latent Semantic Analyses (PLSA) in Bibliometric Analysis for Technology Forecasting

Due to the availability of internet-based abstract services and patent databases, bibliometric analysis has become one of key technology forecasting approaches. Recently, latent semantic analysis (LSA) has been applied to improve the accuracy in document clustering. In this paper, a new LSA method, probabilistic latent semantic analysis (PLSA) which uses probabilistic methods and algebra to search latent space in the corpus is further applied in document clustering. The results show that PLSA is more accurate than LSA and the improved iteration method proposed by authors can simplify the computing process and improve the computing efficiencyDebido a la disponibilidad de servicios abstractos de internet y bases de datos de patentes, un análisis bibliométrico se ha transformado en una aproximación clave de sondeo de tecnologías. Recientemente, el Análisis Semántico Latente (LSA) ha sido aplicado para mejorar la precisión en el clustering de documentos. En el siguiente trabajo se muestra, un nuevo método LSA, el Análisis Semántico Probabilística Latente (PLSA), que utiliza métodos probabilísticas y álgebra para buscar espacio latente en el cuerpo generado por el clustering de documentos. Los resultados demuestran que PLSA es más preciso que LSA y mejora el método de iteración propuesto por autores que simplifican los procesos de computación y mejoran la eficiencia de cómputo.Due to the availability of internet-based abstract services and patent databases, bibliometric analysis has become one of key technology forecasting approaches. Recently, latent semantic analysis (LSA) has been applied to improve the accuracy in document clustering. In this paper, a new LSA method, probabilistic latent semantic analysis (PLSA) which uses probabilistic methods and algebra to search latent space in the corpus is further applied in document clustering. The results show that PLSA is more accurate than LSA and the improved iteration method proposed by authors can simplify the computing process and improve the computing efficienc

Oxide formation at the surface of late 4d transition metals: Insights from first-principles atomistic thermodynamics

Using density-functional theory we assess the stability of bulk and surface oxides of the late 4d transition metals in a ``constrained equilibrium'' with a gas phase formed of O2 and CO. While the stability range of the most stable bulk oxide extends for ruthenium well into gas phase conditions representative of technological CO oxidation catalysis, this is progressively less so for the 4d metals to its right in the periodic system. Surface oxides could nevertheless still be stable under such conditions. These thermodynamic considerations are discussed in the light of recent experiments, emphasizing the role of (surface) oxides as the active phase of model catalysts formed from these metals.Comment: 7 pages including 3 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Real time statistical field theory

We have written a {\it Mathematica} program that calculates the integrand corresponding to any amplitude in the closed-time-path formulation of real time statistical field theory. The program is designed so that it can be used by someone with no previous experience with {\it Mathematica}. It performs the contractions over the tensor indices that appear in real time statistical field theory and gives the result in the 1-2, Keldysh or RA basis. We have used the program to calculate the ward identity for the QED 3-point function, the QED 4-point function for two photons and two fermions, and the QED 5-point function for three photons and two fermions. In real time statistical field theory, there are seven 3-point functions, 15 4-point functions and 31 5-point functions. We produce a table that gives the results for all of these functions. In addition, we give a simple general expression for the KMS conditions between $n$-point green functions and vertex functions, in both the Keldysh and RA basesComment: 25 pages, 12 figure

Mixing and oscillations of neutral particles in Quantum Field Theory

We study the mixing of neutral particles in Quantum Field Theory: neutral boson field and Majorana field are treated in the case of mixing among two generations. We derive the orthogonality of flavor and mass representations and show how to consistently calculate oscillation formulas, which agree with previous results for charged fields and exhibit corrections with respect to the usual quantum mechanical expressions.Comment: 8 pages, revised versio

Prognostic significance of nm23-H1 expression in oral squamous cell carcinoma

Recent studies indicated nm23-H1 played a role in cancer progression. Therefore, we investigated clinical significance of nm23-H1 expression in oral squamous cell carcinoma (OSCC). In total, 86 OSCC specimens were immunohistochemically stained with nm23-H1-specific monoclonal antibodies. Immunohistochemical staining of nm23-H1 was confirmed by immunoblotting. The relations between nm23-H1 expression and clinicopathologic variables were evaluated by chi(2) analysis. As increased size of primary tumour could escalate metastatic potential and the data of patients at the late T stage might confound statistical analyses, we thus paid special attention to 54 patients at the early T stage of OSCC. Statistical difference of survival was compared by a log-rank test. Immunohistochemically, nm23-H1 expression was detected in 48.8% (42 out of 86) of tumorous specimens. It positively correlated with larger primary tumour size (P = 0.03) and inversely with cigarette-smoking habit (P = 0.042). In patients at the early T stage, decreased nm23 expression was associated with increased incidence of lymph node metastasis (P = 0.004) and indicated poor survival (P = 0.014). Tumour nm23-H1 expression is a prognostic factor for predicting better survival in OSCC patients at the early T stage, which may reflect antimetastatic potential of nm23. Therefore, modulation of nm23-H1 expression in cancer cells can provide a novel possibility of improving therapeutic strategy at this stage. In addition, our results further indicated cigarette smoking could aggravate the extent of nm23-H1 expression and possibly disease progression of OSCC patients. (C) 2004 Cancer Research UK