A wideband trapezoidal dielectric resonator antenna with circular polarization

A new design of a circularly-polarized (CP) trapezoidal dielectric resonator antenna (DRA) for wideband wireless application is presented. A single-layered feed is used to excite the trapezoidal shaped dielectric resonator to increase resonant frequency and axial ratio. Besides its structure simplicity, ease of fabrication and low-cost, the proposed antenna features good measured impedance bandwidth, 87.3% at 4.21 GHz to 10.72 GHz frequency bands. Moreover, the antenna also produces 3-dB axial ratio bandwidth of about 710 MHz from 5.17 GHz to 5.88 GHz. The overall size of DRA is 21 mm × 35 mm, which is suitable for mobile devices. Parametric study and measurement results are presented and discussed. Very good agreement is demonstrated between simulated and measured results

A Comprehensive Study of the Radiative Decays of J/ψJ/\psi and ψ(2S)\psi(2S) to Pseudoscalar Meson Pairs, and Search for Glueballs

Using 53 pb$^{-1}$ of $e^+e^-$ annihilation data taken at $\sqrt{s}=3.686$ GeV, a comprehensive study has been made of the radiative decays of samples of 5.1 million $J/\psi$ and 24.5 million $\psi(2S)$ into pairs of pseudoscalar mesons, $\pi^+\pi^-$, $\pi^0\pi^0$, $K^+K^-$, $K_S^0K_S^0$, and $\eta\eta$. Product branching fractions for the radiative decays of $J/\psi$ and $\psi(2S)$ to scalar resonances $f_0(1370,1500,1710,2100, \text{and} 2200)$, and tensor resonances $f_2(1270,1525, \text{and} 2230)$ have been determined, and are discussed in relation to predicted glueballs. For $\psi(2S)$ radiative decays the search for glueballs has been extended to masses between 2.5 GeV and 3.3 GeV.Comment: 21 pages, 14 figures, published in PR

Does it matter where you come from? vertical spillovers from foreign direct investment and the nationality of investors

The authors use a firm-level panel data set from Romania to examine whether the nationality of foreign investors affects the degree of vertical spillovers from foreign direct investment. Investors'country of origin may matter for spillovers to domestic producers in upstream sectors (supplying intermediate inputs) in two ways. First, the share of intermediate inputs sourced by multinationals from a host country is likely to increase with the distance between the host and the source economy. Second, the sourcing pattern is likely to be affected by preferential trade agreements that cover some but not other source economies. In this case, the Association Agreement signed between Romania and the European Union (EU) implies that inputs sourced from the EU are subject to a lower tariff than inputs sourced from America or Asia. Moreover, while for European investors intermediate inputs sourced from home country suppliers comply with the rules of origin and thus can be exported to the EU on preferential terms, this would not be the case for home country suppliers of American or Asian multinationals. Therefore, one would expect that American and Asian investors source more from Romania than EU investors and thus present greater potential for vertical spillovers. The empirical analysis produces evidence in support of the authors'hypothesis. They find a positive association between the presence of American and Asian companies in downstream sectors and the productivity of Romanian firms in the supplying industries. Further, the productivity of Romanian firms in the supplying sectors is negatively correlated with operations of European investors in downstream sectors. The differences between the effects associated with investors of different origin are statistically significant.Economic Theory&Research,Environmental Economics&Policies,International Terrorism&Counterterrorism,Labor Policies,Small and Medium Size Enterprises,Environmental Economics&Policies,International Terrorism&Counterterrorism,Economic Theory&Research,Microfinance,Private Participation in Infrastructure