Loss characteristics of high-/spl epsiv//sub r/ microstrip lines fabricated by an etchable thick-film on ceramic MCM technology

Etchable thick-film multi-chip-module (MCM) technology has led to the possibility of fabricating microwave integrated circuits (MICs) with performance similar to MICs produced using more expensive conventional thin-film MCM-D techniques. However, little data is available on the loss characteristics of the technology at microwave frequencies. This paper describes an experimental investigation into the loss properties of high-definition etchable thick-film MCM microstrip lines formed on a variety of high dielectric constant (high-/spl epsiv//sub r/) ceramic substrates. Substrates investigated comprise 96% alumina (/spl epsiv//sub r/=9.5), (Zr,Sn)TiO/sub 4/(/spl epsiv//sub r/=36.6) and BaO-PbO-Nd/sub 2/O/sub 3/-TiO/sub 2/ (/spl epsiv//sub r/=90.9). Microstrip loss properties are determined by fabricating a series of loosely coupled half-wave resonators on each substrate, with a range of characteristic impedance values. Measurements to 6 GHz are compared to those for similar lines fabricated using conventional thin-film MCM-D technology. The results demonstrate that etchable thick-film MCM technology provides many of the advantages of thin-film MCM-D technology, such as low-loss and high-definition conductors, and is suitable for the cost-effective fabrication of miniaturised high-performance microstrip MICs in high volume.     

The economics of energy efficiency for the poor—a South African case study

South Africa’s Reconstruction and Development Programme set ambitious goals for providing basic services to all, including housing and electrification. More efficient use of energy has the potential to socially and politically support these goals, particularly when it is targeted at low-income communities lacking adequate energy services. This paper examines the economics of energy efficiency for the urban poor from the perspective of society, utilities and poor consumers, using five example programmes. While the five energy efficiency programmes generally have significant economic and environmental benefits from a social perspective, they may not be as attractive to utilities and consumers. Also examined are the policy options for overcoming the significant barriers to energy efficiency, and ways government can bridge the gap between what is good for society and what is good for the electricity industry.     

Individual differences in extended practice functions and solution strategies for basic addition facts.

Practice on addition basic facts and changes in solution strategies were examined in 3rd- and 4th-grade students, practicing over 3 months. Response latencies decreased, indicating positive practice effects. Each of 3 student groups demonstrated different solution–strategy mixtures. Different mixtures led to different practice effects, indexed by shifts to more efficient counting strategies and more direct retrieval. Expectations about effects of practice and instructional strategies for optimizing practice must be sensitive to a child's actual strategy pattern. Most students had decreasing latency practice functions. However, quantitative functions fit to the practice session data indicated a high proportion of cases where the latency pattern over sessions was nonmonotonic. Trends over a small number of practice sessions may be inadequate for decisions about the utility of further practice, because such data may poorly represent long-term, cumulative effects on modifying strategy usage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-power etched-facet lasers

We demonstrate, for the first time, laser diodes with anetched facet fabricated by chemically assisted ion beametching, producing 1?7 W pulsed and 470mW CW output power from one facet. The devices were coated and bonded junction-side-up and tested at room temperature. The single 40 ?m stripe, 300 ?m-long devices exhibit 94 mA threshold current and differential quantum efficiencies of 80% pulsed (78% CW).     

Expression, exon-intron organization, and chromosome mapping of the human sodium iodide symporter

The active iodide uptake of the thyroid gland in humans is mediated by the human sodium iodide symporter (hNIS). In this report, we show that hNIS expression was detected primarily in thyroid tissue, but also in breast, colon, and ovary tissues. Expression of hNIS is greatly reduced in thyroid tumors compared to normal thyroid tissue. Among tumor tissues, hNIS expression appears to be variable, consistent with the variable response to radioiodide treatment observed for thyroid carcinomas. The coding region of hNIS is interrupted by 14 introns, and the nucleotide sequence of each exon-intron junction is reported. Using this information, an alternatively spliced form of hNIS was identified. Finally, the chromosome location of the hNIS gene was mapped to chromosome 19p.     

Sensitization of the startle reflex by footshock: Blockade by lesions of the central nucleus of the amygdala or its efferent pathway to the brainstem.

Bilateral electrolytic lesions of the central, but not the lateral, nucleus of the amgydala blocked shock sensitization of startle (the increase in startle produced by presentation of ten 0.6-mA footshocks in rapid succession). Lesions of the central nucleus also decreased reactivity to shock (jumping and flinching) during shock presentation. However, this decrease in reactivity cannot account for the blockade of shock sensitization, because when a higher shock intensity (1.0 mA) was used, producing equivalent reactivity to that of controls at 0.6 mA, central nucleus lesions still blocked shock sensitization. Moreover, lesions of the caudal part of the ventral amygdalofugal pathway, which carries central nucleus efferents to the startle reflex pathway, also blocked shock sensitization. It is hypothesized that shock activates the central nucleus of the amygdala, which increases startle through modulation of the startle pathway. Activation of the amygdala by shock may be the unconditioned response relevant for fear conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of serum levels of exogenously administered FSH and LH during ovulation induction therapy

The available surgical and non-surgical therapy options for treatment of gallstone disease are presented. Conventional cholecystectomy is regarded as standard therapy of symptomatic cholecystolithiasis. Other modes of therapy may be indicated under certain circumstances, depending on the results of imaging procedures. In this context conventional X-ray examination, oral and intravenous cholecystography, sonography, computed tomography, endoscopic retrograde cholangiography/cholecystography, and magnetic resonance imaging are discussed and their influence on therapeutic decisions is explained.