Numerical study of the spectral 3-D green's function singularities for piezoelectric SAW components

This article deals with the numerical study of the singularities appearing in the spectral 3-D Green's function associated with the piezoelectric surface acoustic wave components (so-called SAW components). These electrical units are currently used today in several devices produced by the telecommunications industry (radio, TV, radar, and digital telecommunication systems). The need to improve their performance has motivated engineers and researchers to use mathematical modeling intensively, in particular the integral equations technique here used, which requires the computing of the associated Green's function and the study of its properties.     

Spanish Scientific Productivity and Equipment in Magnetic Resonance from a Regional and European Perspective

The aim of this work was to provide a rational frame for the design of scientific policies in MR infrastructure implementation. To this end, we have investigated the relationships between MR instruments, their scientific productivity or medical performance and several socio-economic, R&D or health care indicators in a Spanish and European context. The distribution of MR spectroscopy instruments among Spanish Autonomous Communities suggests that the allocation policy resulted from a compromise between the pull of demand based on regional strength in R&D activities and the push of convergence criteria to bring underdeveloped regions up to a national standard. On the whole, the average value for Spanish MR spectroscopy equipment (1.6 units per TRDP) was within the average value of 1.7 found in 6 European countries. The scientific productivity of these spectrometres in Spain (10.3 publications per unit), compares with the ratio (12.4) found in the United Kingdom and was above the six countries' average (8.3). Larger differences in productivity were observed between Spanish Autonomous Communities, suggesting the existence of important laguna in the distributive side of the allocation policy. Consistent with its socio-sanitary importance, the regional distribution of MR imaging equipment in Spain correlated with the number of sanitary personnel and regional population or wealth. The average number of installed units per million inhabitants in Spain (3.3) is very close to the average found in five European countries and the diagnostic procedures per installed units are close to the 5 countries' average values of 3400/year. However, the scientific productivity of MR imaging equipment in Spain (1.6 publications per installed unit in the five year period) was very low as compared with other European countries (3.7 on average). Higher diagnostic demand or lower publication pressures could explain these differences equally well. Our results suggest that increases in scientific productivity and medical performance of MR instrumentation in Spanish Autonomous Communities may not necessarily involve a net increase in the number of MR instruments but rather, improvements in the global socio-economic throughputs derived from the organisation of R&D and medical service policies.     

Knowledge Discovery with Genetic Programming for Providing Feedback to Courseware Authors

We introduce a methodology to improve Adaptive Systems for Web-Based Education. This methodology uses evolutionary algorithms as a data mining method for discovering interesting relationships in students usage data. Such knowledge may be very useful for teachers and course authors to select the most appropriate modifications to improve the effectiveness of the course. We use Grammar-Based Genetic Programming (GBGP) with multi-objective optimization techniques to discover prediction rules. We present a specific data mining tool that can help non-experts in data mining carry out the complete rule discovery process, and demonstrate its utility by applying it to an adaptive Linux course that we developed.     

Light emission diode water thermometer: a low-cost and noninvasive strategy for monitoring temperature in aqueous solutions

A spectroscopic device for monitoring the temperature of aqueous solutions is presented. It uses a 950 nm light emission diode as light source and two photodiodes as detectors. Temperature is monitored following the thermally induced absorbance changes of the water-OH second overtone (approximately 960 nm). A linear response between the light absorbed by an aqueous solution and its temperature is found in the range from 15 to 95 degrees C. A prediction error of 0.1 degrees C and a precision of 0.07 degrees C in temperature measurement can be achieved. Up to 0.1 M of electrolyte concentration can be present in the solution without significantly affecting the temperature measurement. Different strategies, such as remote (noninvasive) or in situ (using a fiber-optic probe) temperature measurement, are shown, and their relative advantages are discussed.     

Effect of Magnesia Blending on the Magnetic Properties of Grain Oriented Silicon Steel

Decarburized samples of grain oriented silicon steel were coated with alone and blended magnesias and submitted to the high temperature annealing. The magnesias and their blendings were characterized using granulometry measurements, ignition loss and reactivity tests. After high temperature annealing, forsterite film morphology, magnetic properties and Goss deviation were also analyzed. Better magnetic properties and sharper Goss orientation were found in samples which had used blended magnesias. These results are explained by the magnesias particle size distributions, forsterite film formation and rate of inhibitors release.     

Tissue alterations in the Guinea pig lateral prostate following antiandrogen flutamide therapy.

The flutamide antiandrogenic effects on the Guinea pig male prostate morphology in puberal, post-puberal and adult ages were evaluated in the present study. Daily-treated group animals received flutamide subcutaneous injection at a dose of 10 mg/Kg body weight for 10 days. The control group animals received a pharmacological vehicle under the same conditions. The lateral prostate was removed, fixed and processed for light and transmission electron microscopy. The results revealed an increase of the acinus diameter in the treated puberal animals and straitness in the stromal compartment around the acini. The epithelial cells exhibited cubic phenotype. In the post-puberal and adult animals, a decrease of the acinus diameter was observed, as well as an increase of the smooth muscle layer and presence of the folds at epithelium. The ultrastructural evaluation of the secretory cells in the treated group demonstrated endomembrane enlargement, mainly in the rough endoplasmic reticulum and Golgi apparatus. In addition, a decrease of the microvilli and alterations in the distribution patterns and density of the stromal fibrillar components were observed. In conclusion, the flutamide treatment exerts tissue effects on the lateral prostate, promoting stroma/epithelium alterations.     

A Module for BiST of CMOS RF Receivers

A module to perform a built-in self-test in CMOS RF receivers is presented. The module is associated with a test strategy consisting of measuring the main performance parameters of the single building blocks individually. Circuitry overhead, however, is kept low by using some blocks as part of the test set-up and reusing them. The test overhead has also been reduced by replacing direct determination of performance parameters with their estimation. The test methodology has been applied to a mixer in the first down conversion stage of a GSM receiver, estimating its conversion gain, 1dB compression and third-order interception points. Using the output of the IF amplifier as the only testing point, the rms errors in the estimation of the above mentioned parameters are 1.5, 3.0 and 2.7%, respectively.

The Social Media Basis of Youth Protest Behavior: The Case of Chile

Protest activity has become a central means for political change in Chile. We examine the association between social media use and youth protest, as well as mediating and moderating mechanisms of this relationship, using survey data collected in Chile in 2010. We found that Facebook use was associated significantly with protest activity, even after taking into account political grievances, material and psychological resources, values, and news media use. The link between overall Facebook use and protest activity was explained by using the social network for news and socializing rather than when it was used for self‐expression. Postmaterialist values and political ideologies were not found to moderate the association between Facebook use and protest.     

Pyrometer model based on sensor physical structure and thermal operation

This paper proposes a new simplified thermal model for pyrometers, which takes into account both their internal and external physical structure and operation. The model is experimentally tested on the REMS GTS, an instrument for measuring ground temperature, which is part of the payload of the NASA MSL mission to Mars. The proposed model is based on an energy balance equation that represents the heat fluxes exchanged between sensor elements through radiation, conduction and convection. Despite being mathematically more complex than the more commonly used model, the proposed model makes it possible to design a methodology to compensate the effects of sensor spatial thermal gradients. The paper includes a practical methodology for identifying model constants, which is part of the GTS instrument calibration plan and uses a differential approach to avoid setup errors. Experimental results of the model identification methodology and a target temperature measurement performance after identification has been made are reported. Results demonstrate the good behaviour of the model, with errors below 0.15 °C in target temperature estimates.