Economic outcomes of international public relations: A time-series analysis at the country level

This study examines the causal relationship between international public relations expenditure and its economic returns at the country level. In order to overcome the limitations of previous studies that have attempted to quantify the outcomes of public relations efforts and investments using correlations, this study conducted a more rigorous causality test by measuring the relationship between data series using time-series analysis. International public relations expenditure data were collected from the semi-annual reports of the Foreign Agency Registration Act (FARA), from 1996 to 2009. The economic outcomes analyzed include US imports from the client countries and US foreign direct investment toward the client countries. Four countries (Japan, Colombia, Belgium, and the Philippines) were selected to constitute the sample. Based on the results of the unit-root test and the co-integration test, the relationship was analyzed using three models of the Granger causality test: (1) the simple Autoregressive Distributed Lag Model, (2) the Vector Error Correction Model, and (3) the Toda and Yamamoto version of the Granger non-causality test. The results show that past public relations expenditure holds power in forecasting the economic outcomes for Japan, Belgium, and the Philippines. This was not the case, however, for Colombia, whose historically strong economic and cultural ties with the US may have shifted the direction of causation from economic outcome to PR expenditure

A carbon nanotubes-silicon nanoparticles network for high performance lithium rechargeable battery anodes

As an effort to address the chronic capacity fading of Si anodes and thus achieve their robust cycling performance, herein, we develop a unique electrode in which silicon nanoparticles are embedded in the carbon nanotubes network. Utilizing robust contacts between silicon nanoparticles and carbon nanotubes, the composite electrodes exhibit excellent electrochemical performance : 95.5% capacity retention after 140 cycles as well as rate capability such that at the C-rate increase from 0.1C to 1C to 10C, the specific capacities of 850, 698, and 312 mAh/g are obtained, respectively. The present investigation suggests a useful design principle for silicon as well as other high capacity alloying electrodes that undergo large volume expansions during battery operations.

Temperature dependence of Mott transition in VO_2 and programmable critical temperature sensor

The temperature dependence of the Mott metal-insulator transition (MIT) is studied with a VO_2-based two-terminal device. When a constant voltage is applied to the device, an abrupt current jump is observed with temperature. With increasing applied voltages, the transition temperature of the MIT current jump decreases. We find a monoclinic and electronically correlated metal (MCM) phase between the abrupt current jump and the structural phase transition (SPT). After the transition from insulator to metal, a linear increase in current (or conductivity) is shown with temperature until the current becomes a constant maximum value above T_{SPT}=68^oC. The SPT is confirmed by micro-Raman spectroscopy measurements. Optical microscopy analysis reveals the absence of the local current path in micro scale in the VO_2 device. The current uniformly flows throughout the surface of the VO_2 film when the MIT occurs. This device can be used as a programmable critical temperature sensor.Comment: 4 pages, 3 figure