Increased liking for a solution is not necessary for the attenuation of neophobia in rats.

Recent evidence suggests that liking and wanting of food rewards can be experimentally dissociated (e.g., Berridge, 1996); this dissociation extends to attenuated neophobia in the present study. Rats tend to eat less of a novel food than a familiar food, a phenomenon called neophobia. The present experiments evaluated whether attenuation of neophobia by prior exposure reflects enhanced liking of the flavor using the Taste Reactivity (TR) test. In Experiment 1, rats given five 10-s TR trials with water or various concentrations of saccharin solution (0.1%, 0.2%, 0.5%) did not show a change in the number of hedonic reactions displayed across trials. However, in a subsequent consumption test from a bottle containing 0.25% saccharin solution, rats with no prior saccharin exposure (group water) consumed less than rats with prior saccharin exposure; that is they displayed neophobia. In Experiment 2, whether rats received five 10-s TR trials with water or 0.5% saccharin solution, they did not display a difference in hedonic reactions to 0.25% saccharin solution in two 5-min TR test trials. These results suggest that the attenuation of neophobia is evidenced as an increase in the tendency to approach a bottle containing the flavored solution (wanting), but not as an enhanced liking of that solution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accumulation of gas‐phase methamphetamine on clothing,toy fabrics,and skin oil

To better understand methamphetamine exposure and risk for occupants of former residential clandestine methamphetamine laboratories, we measured the dynamic accumulation of methamphetamine in skin oil, cotton and polyester (PE) clothing, upholstery, and toy fabric (substrates) exposed to 15–30 ppb (91–183 μg/m³) neutral methamphetamine in air for up to 60 days. The average equilibrium partition coefficients at 30% RH, in units of μg of methamphetamine per gram of substrate per ppb, are 3.0 ± 0.2 for a PE baby blanket, 5.6 ± 3.5 for a PE fabric toy, 3.7 ± 0.2 for a PE shirt, 18.3 ± 8.0 for a PE/cotton upholstery fabric, and 1200 ± 570 in skin oil. The partition coefficients at 60% RH are 4.5 ± 0.4, 5.2 ± 2.1, 4.5 ± 0.6, 36.1 ± 3.6, and 1600 ± 1100 μg/(g ppb), respectively. There was no difference in the partition coefficient for a clean and skin‐oil‐soiled cotton shirt [15.3 ± 2.1 μg/(g ppb) @ 42 days]. Partition coefficients for skin oil may be sensitive to composition. ‘Mouthing’ of cloth is predicted to be the dominant exposure pathway [60 μg/(kg body weight*ppb)] for a toddler in former meth lab, and indoor air concentrations would have to be very low (0.001 ppb) to meet the recommended reference dose for children.     

Characterization of Morphological Changes in Agglomerates Subject to Condensation and Evaporation Using Multiple Fractal Dimensions

Multiple fractal dimensions are used to characterize morphological changes that occur when an aerosol composed of irregularly shaped agglomerates is subject to condensation followed by evaporation. The agglomerates change from a branched, chainlike structure to a more regular, near-spherical or clumplike structure reflected in a decrease in the structural fractal dimension. The textural fractal dimension remains constant because the primary particles, of which the agglomerates are composed, do not change in shape. The degree of supersaturation and the number of condensation-evaporation cycles that the aerosol undergoes are major factors that influence morphological change. Even at low supersaturations, increasing the number of condensation-evaporation cycles makes the agglomerates more regular and thus decreases the structural fractal dimension. The transition point in the Richardson plot is a good indicator of the size of the primary particles in the agglomerate.     

A new undergraduate computer arithmetic software laboratory

An undergraduate computer engineering laboratory that supports a one-quarter computer arithmetic course is described. This course is required for the computer engineering degree and is taken as a technical option by many students in electrical engineering and computer science. The features of this state-of-the-art laboratory include a local area network of computers, remote access via the campus network, electronic mail, online documentation, and automatic program submittal, grading, and plagiarism detection     

Deconvolution estimation of nerve conduction velocity distribution

A conduction velocity distribution (CVD) estimator that incorporates volume conductor modeling of the nerve-evoked response is introduced in this paper. The CVD estimates are obtained from two compound nerve action potentials (CNAP) recorded at the skin surface. A third channel is introduced in order to assess the estimator performance in the experimental case. The relevance of using an accurate signal model is shown by comparing the performance of the proposed estimator with a previous approach based on a different CNAP model. The performance of the proposed estimator is evaluated for simulated and experimental data. The study assesses signal-to-noise ratio immunity and sensitivity to errors in the model parameters.     

Least-mean-squares algorithm to determine submicrometer particle diameter,volume fraction,and size distribution width by elastic light scattering

A computationally fast method to determine values and their uncertainty for particulate system volume median diameter, volume fraction, and size distribution width is presented. These properties cannot be obtained for submicrometer particulate by diffraction-based methods. The technique relies on a least-mean-squares method applied over a prespecified size range and distribution width. Prespecifying the range significantly reduces the number of calculations required to determine the particulate parameters from experimental data, allowing the practical evaluation of large data sets. The solution method that was developed has significant advantages over ratio-style calculations that are more commonly performed, the primary of which is a simple method to determine errors in the measurement parameters. We evaluated the predicted performance for a specific experimental system for various levels of noise, with monodisperse and log-normal distributions, by analyzing synthetic data with the algorithm. Results were a quantitative statement of system accuracy. In addition, synthetic log-normal data evaluated with monodisperse models revealed significant and systematic errors in the predicted volume median diameter. These errors indicate that, in general, systems with a significant size distribution width must be analyzed with a model that includes this size distribution. Finally, calibrated polystyrene spheres were measured with an experimental system that used four simultaneous scattering measurements, and all diameters were within the reported uncertainty.