The indirect hemagglutination test for onchocerciasis performed with blood collected on filter paper

In Guatemala, an indirect hemagglutination (IHA) test for onchocerciasis, performed with a crude saline extract of Onchocerca volvulus and blood samples taken on filter paper, showed a high level of sensitivity and specificity. IHA titers of blood samples from the ear lobe taken on filter paper and of sera obtained by venipuncture showed a high correlation.     

Optimal discrete-time control system with cost for observation

The problem of how to select the total number and the spacings of the observations optimally when a constant cost is incurred for each observation taken is discussed. Approximate expressions for the criterion function with a fixed number of observations are obtained and are used to determine the optimal total number of observations. For a class of multidimensional systems with a dominant eigenvalue, the problem is shown to reduce to that for scalar systems. Detailed discussion is then carded out for scalar systems including some sensitivity study.     

Characterization of polymer-adhesive interfaces on a nanometre scale by elemental mapping and image EELS using EFTEM

Energy-filtering transmission electron microscopy (EFTEM) was applied for investigating interfaces between a polymer and an adhesive. The sample employed in this work is polybutylene terephtharate (PBT) sheets laminated with an epoxy adhesive. It was found that heat aging of the PBT at 180 degrees C in air for > 9 h prior to adhesion decreases the adhesion strength drastically. To investigate this unfavourable aging effect on the adhesion strength, we performed elemental mapping and image EELS using EFTEM. A weak boundary layer with a thickness of < 50 nm was visualized at the PBT-adhesive interface by elemental mapping in the sample subjected to the heat aging and image EELS revealed the origin of this layer. Thus, we clearly correlated the nanoscale interfacial structure with the adhesion strength by EFTEM.     

Microassembly of semiconductor three-dimensional photonic crystals

Electronic devices and their highly integrated components formed from semiconductor crystals contain complex three-dimensional (3D) arrangements of elements and wiring. Photonic crystals, being analogous to semiconductor crystals, are expected to require a 3D structure to form successful optoelectronic devices. Here, we report a novel fabrication technology for a semiconductor 3D photonic crystal by uniting integrated circuit processing technology with micromanipulation. Four- to twenty-layered (five periods) crystals, including one with a controlled defect, for infrared wavelengths of 3-4.5 microm, were integrated at predetermined positions on a chip (structural error <50 nm). Numerical calculations revealed that a transmission peak observed at the upper frequency edge of the bandgap originated from the excitation of a resonant guided mode in the defective layers. Despite their importance, detailed discussions on the defective modes of 3D photonic crystals for such short wavelengths have not been reported before. This technology offers great potential for the production of optical wavelength photonic crystal devices.     

Optical Burst Switching Router With 40-,10-Gb/s Bit-Rate Transparent Contention Resolution

We report a bit-rate transparent optical burst switching (OBS) router prototype using a fast 5 times 5 PLZT [(Pb,La)(Zr,Ti)O₃ ] optical matrix switch. Dynamic switching in a two-wavelength, 2 times 2 OBS switch is demonstrated. Contention resolution using a tunable Mach-Zehnder interferometer wavelength converter for both 40- and 10-Gb/s bursts is demonstrated for the first time. Error-free operation was achieved for both bit rates under the same settings, as required in autonomous networks     

Analysis and Design of a Dynamic Predistorter for WCDMA Handset Power Amplifiers

This paper presents a dynamic predistorter (PD), which linearizes the dynamic AM-AM and AM-PM of a wideband code division multiple access handset power amplifier (PA). The dynamic PD allows an adjacent channel leakage power ratio (ACPR) improvement of 15.7 dB, which is superior to conventional PDs that linearize static AM-AM and AM-PM. The dynamic PD was designed using an HBT generating nonlinearity, a short circuit at the baseband (les4 MHz), and a load circuit for the HBT at the RF fundamental band (ap1.95 GHz). Volterra-series analysis was performed to understand the mechanism of the dynamic PD. The analysis revealed that the short circuit at the baseband enabled the dynamic PD generating third-order intermodulation distortion (IMD3) with opposite phase to the fundamental tone (i.e., antiphase IMD3). The antiphase IMD3 allows dynamic gain compression, which linearizes the dynamic gain expansion of a PA with low quiescent current. The analysis also revealed that the IMD3 amplitude of the dynamic PD can be adjusted by load impedance at the RF fundamental band, which enables the gradient of dynamic AM-AM and AM-PM to be optimized to linearize the PA. The fabricated two-stage InGaP/GaAs HBT PA module with the dynamic PD exhibited an ACPR of -40 dBc and a power-added efficiency of 50% at an average output power of 26.8 dBm with a quiescent current of 20 mA     

High-Speed X-Cut Thin-Sheet LiNbO3 Optical Modulator With Folded Structure

We propose a small-footprint X-cut thin-sheet lithium niobate optical modulator with high-speed and low-driving-voltage characteristics. Since an optical waveguide is folded by a mirror placed at one edge of the modulation chip, the chip can be shortened by about half. In addition, a wide modulation bandwidth can be achieved, because the path-length difference between the optical waveguide and the coplanar-waveguide (CPW) electrode is decreased to as short as possible by placing the CPW electrode as far as possible along the optical waveguide in the folded portion, and the microwave effective index is set to realize effective velocity matching between the lightwave and the microwave. A small footprint of 1.78 times 29 mm, a low half-wave voltage of 2.0 V at dc, and a 3-dBe modulation bandwidth of 20 GHz were obtained.     

Microfabrication of DC microarcjets with UV lasers

Microfabrication of a microarcjet with Fifth-harmonic generation Nd:YAG pulses (wavelength 213 nm) and its plasma acceleration characteristics was investigated. The microarcjet with a rectangular exit of 0.44 mm in height was machined in a 1.2 mm thick quartz plate. For electrodes, Au films of 100 nm in thickness were coated on a divergent part of the nozzle for anode and an inner wall surface for cathode. In operational tests, a stable discharge was observed for mass flow of 1.0 mg/s, discharge current of 6 mA, discharge voltage of 600 V, or 3.6 W input power. With the 3.6 W input power, plasma speed of 1441 m/s and an energy efficiency of 7% were obtained.     

A Test Statistic in Canonical Correlation Analysis for Categorical Variables

In canonical correlation analysis (CCA), it is important to estimate the number of nonzero canonical correlations in the population. One way to estimate the number is to consider the dimensionality testing problem. In CCA for continuous variables, some test statistics for the problem have been derived under the normality assumption. However, there are only a few papers on test statistics in CCA for categorical variables.

In this article, a test statistic in CCA for categorical variables is suggested. The test statistic is derived from the rational used for continuous variables. Some properties of the test statistic are examined through mathematical investigations and numerical simulations.