Nanocomposite epoxy coatings containing rare earth ion-doped LaF3 nanoparticles: Film preparation and characterization

New epoxy-based nanostructured materials containing lanthanide ions doped LaF₃ nanoparticles were obtained by cationic UV-induced ring-opening polymerization.The lanthanide Er³⁺ and Yb³⁺ ions were added as dopant to LaF₃ nanoparticles. The synthesized NPs were solubilized into cyclohexene oxide and afterwards dispersed, in the range between 3 and 20 wt.%, into CE as dicycloaliphatic epoxy resin. The cured films were completely transparent and TEM analysis showed the absence of macroscopic agglomeration. The fast UV curing process was shown to be efficient on “freezing” the good nanometric dispersion achieved in the liquid formulations. These new materials could find suitable applications in optical communication and in LASER waveguide direct writing.     

Habituation and sensitization of aggression in bullfrogs (Rana catesbeiana): Testing the dual-process theory of habituation.

The aggressive response of male bullfrogs (Rana catesbeiana) habituates with repeated broadcasts of acoustic stimuli simulating a new territorial neighbor. The effects of stimulus repetition rate and stimulus intensity on bullfrog aggressive responses were tested in a field experiment designed to test the assumptions of a dual-process theory of habituation. Synthetic advertisement calls were broadcast at 2 repetition rates and 2 intensities in a factorial design. Bullfrogs were more aggressive at the higher stimulus intensity at both repetition rates. Aggressive responses habituated more slowly at the higher stimulus intensity and slower repetition rate compared with other treatments. Several biotic and abiotic factors had small or negligible effects on aggressive responses. Although consistent with the operation of 2 opposing processes, habituation and sensitization, the data provide only partial support for the assumptions of dual-process theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When choice is demotivating: Can one desire too much of a good thing?

Current psychological theory and research affirm the positive affective and motivational consequences of having personal choice. These findings have led to the popular notion that the more choice, the better—that the human ability to manage, and the human desire for, choice is unlimited. Findings from 3 experimental studies starkly challenge this implicit assumption that having more choices is necessarily more intrinsically motivating than having fewer. These experiments, which were conducted in both field and laboratory settings, show that people are more likely to purchase gourmet jams or chocolates or to undertake optional class essay assignments when offered a limited array of 6 choices rather than a more extensive array of 24 or 30 choices. Moreover, participants actually reported greater subsequent satisfaction with their selections and wrote better essays when their original set of options had been limited. Implications for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parametric statistics and levels of measurement: Factorial designs and multiple regression.

Let Y be a continuous, ordinal measure of a latent variable Θ. In general, for factorial designs, an analysis of variance of the observed variable Y cannot be used to draw inferences about main effects and interactions on the latent variable Θ even when the standard normality and equality of variance assumptions hold. If Y is a continuous, ordinal measure of a latent variable Θ; X?,…, Xn are continuous, ordinal measures of latent variables Φ?,…, Φn; and the observed measures have a multivariate normal distribution, then a multiple regression analysis of the observed criterion measure Y and predictors X?,…, Xn can be used to test hypotheses about multivariate associations among the latent variables. Furthermore, the predicted values Y′ are unbiased estimates of quantities that are monotonically related to predicted values on the latent criterion variable Θ. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Current wrought magnesium alloys: Strengths and weaknesses

The opportunities for extruded and sheet magnesium products in the automotive industry, in particular, are increasing as the quest for lightweighting gains momentum. However, the current alloys all have limitations and these are accentuated when higher productivity targets are also imposed. This article attempts to summarize the strengths and weaknesses of the current wrought alloys, with particular emphasis on the extrusion process, and also considers alternative processing routes which may be useful in overcoming some of these shortcomings. For more information, contact Colleen Bettles, CMIT Private Bag 33, Clayton South MDC, Clayton Victoria 3169, Australia; +61-3-95452936; fax +61-3-95441128; e-mail Colleen.Bettles@csiro.au.     

Hippocampal lesions and associated learning in the pigeon.

The performance of pigeons with hippocampal lesions was compared with that of unoperated and neostriatal-lesioned control Ss in 3 experiments. In Experiment 1, hippocampal-lesioned birds were retarded in the acquisition and the maintenance levels of autoshaped responding. However, the deficit was attenuated following the addition of a response contingency to the autoshaping schedule. In Experiment 2, the hippocampal-lesioned birds showed impaired performance on a differential reinforcement of low rates of responding schedule. From the high levels of responding in Experiment 2, underresponding was observed in hippocampal-lesioned birds relative to control Ss on return to the autoshaping schedule in Experiment 3. Results are interpreted in terms of impaired classical conditioning in hippocampal-lesioned birds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Turing's Test and the ideology of artificial intelligence

A close examination is offered of the Turing Test, whose lasting influence is ascribed to its power as a myth which is expressive of the ideology that underlies strong AI claims. Arguments are advanced to show that the Test is not a bonafide thought-experiment, nor an acceptable substitute for the question, Can a Machine Think? AI work is held to be highly valuable, but by reason of its achievement of thought-like results through the power of algorithms, not through its supposed emulation of thought. Finally, evidence is offered for thinking that the issue at hand is not only a practical, but an urgent one.     

The relationship between HMW glutenin subunit composition and the bread-making quality of British-grown wheat varieties

Based on previous work, which related individual HMW glutenin subunits to bread-making quality by genetical analysis, quality scores were assigned to each of the commonly occurring subunits. The grain proteins of 84 home-grown wheat varieties were fractionated by SDS—PAGE to determine their HMW glutenin subunit composition. The quality scores of each of the subunits were summed to create a Glu-1 quality score for each variety. The results indicated that 47-60% of the variation in the independently established bread-making qualities of this set of varieties could be accounted for by variation in HMW subunits of glutenin. The presence or absence in the varieties of a translocated chromosome, which consisted of the long arm of 1B and the short arm of 1R from rye, was also established because of its known association with poor bread-making quality. A correction factor was applied to the Glu-1 quality score of those varieties that contained the 1 BLURS chromosome. The variations in the rye-adjusted Glu-1 quality scores were compared with those of the bread-making qualities of the varieties, and the proportion of variation in quality accounted for was raised to 55-67%. The Glu-1 quality score and the biscuit-making qualities of the same set of varieties were negatively related. The results are discussed in relation to future strategies recommended to wheat breeders for developing new varieties with improved bread-making quality.