Two hemispheres—two networks: a computational model explaining hemispheric asymmetries while reading ambiguous words

A computational model for reading that takes into account the different processing abilities of the two cerebral hemispheres is presented. This dual hemispheric reading model closely follows the original computational lines due to Kowamoto (J Mem Lang 32:474–516, 1993) but postulates a difference in architecture between the right and left hemispheres. Specifically it is assumed that orthographic, phonological and semantic units are completely connected in the left hemisphere, while there are no direct connections between phonological and orthographic units in the right hemisphere. It is claimed that this architectural difference results in hemisphere asymmetries in resolving lexical ambiguity and more broadly in the processing of written words. Simulation results bear this out. First, we show that the two networks successfully simulate the time course of lexical selection in the two cerebral hemispheres. Further, we were able to see a computational advantage of two separate networks, when information is transferred from the right hemisphere network to the left hemisphere network. Finally, beyond reproducing known empirical data, this dual hemispheric reading model makes novel and surprising predictions that were found to be consistent with new human data.     

Numerical Study of Particle Motion in Jet Milling

Jet mills are common devices used in industry for fine milling of dry particulate materials. The size reduction is caused by repeated events of impacts between particles. Although many parameters affect the performance of a jet mill, only a few of them were investigated. Particles' motions in a jet mill have great influence on the comminution process and energy consumption. Therefore, as a first step for a full simulation of the jet-mill process, it was decided to investigate the particle motion inside the jet mill by neglecting particle-particle interaction and particle breakage. In this way, the numerical simulations provide a better understanding of the classification process. In the present study, three-dimensional numerical simulations of particle motion in an industrial full-scale jet mill were conducted. The predictions of the numerical simulations were compared with experimental data and used to analyze the flow field characteristics.     

Improving the relaxivity by dimerizing Gd-AAZTA: Insights for enhancing the sensitivity of MRI contrast agents

The synthesis of a dimeric derivative of Gd-AAZTA is reported. It retains the basic properties of the parent complex (q = 2, high stability) and displays a relaxivity of 14.0 mM^?1 s^?1 at 20 MHz and 298 K. The outstanding relaxivity is the result of the increased molecular reorientational time and of the contribution arising from 4 to 5 water molecules in the second coordination sphere of the Gd(III) ions.     

International society of sports nutrition position stand: caffeine and performance

Background

We compared Glycine Propionyl-L-Carnitine (GlycoCarn^®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO₂), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men.

Methods

Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn^®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO₂ was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set.

Results

A condition effect was noted for StO₂ at the start of exercise (p = 0.02), with GlycoCarn^® higher than SUPP2. A condition effect was also noted for StO₂ at the end of exercise (p = 0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05); however, MDA decreased 13.7% with GlycoCarn^® and increased in all other conditions. Only a time effect was noted for HLa (p < 0.0001), with values increasing from pre- to post-exercise. No effects were noted for HR, RPE, or for any exercise performance variables (p > 0.05); however, GlycoCarn^® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%).

Conclusion

None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn^® in terms of higher StO₂ at the start of exercise. GlycoCarn^® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn^®) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.     

Scintillation index for two Gaussian laser beams with different wavelengths in weak atmospheric turbulence

We study the propagation of the two lowest-order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation and assuming a slow detector, we calculate the longitudinal and radial components of the scintillation index for a typical free-space laser communication setup. We find the optimal configuration of the two laser beams with respect to the longitudinal scintillation index. We show that the value of the longitudinal scintillation for the optimal two-beam configuration is smaller by more than 50% compared with the value for a single lowest-order Gaussian beam with the same total power. Furthermore, the radial scintillation for the optimal two-beam system is smaller by 35%-40% compared with the radial scintillation in the single-beam case. Further insight into the reduction of intensity fluctuations is gained by analyzing the self- and cross-intensity contributions to the scintillation index.     

Evaluation of urinary methoxyphenols as biomarkers of woodsmoke exposure

Urinary methoxyphenols have been proposed as biomarkers for woodsmoke exposure, but the relationship between exposure and urinary methoxyphenol concentrations has not been characterized. We collected personal particulate matter2.5 and urine samples from 9 adults experimentally exposed to smoke from an open wood fire to characterize this relationship. Personal exposures (PM2.5 mean 1500 microg/ m3) varied 3.5-fold. Twenty-two methoxyphenols, levoglucosan, and 17 polynuclear hydrocarbons were quantified by gas chromatography/mass spectrometry assays for personal filter samples and urine samples. Most methoxyphenols had measurable preexposure levels. Propylguaiacol, syringol, methylsyringol, ethylsyringol, and propylsyringol had peak urinary concentrations after the woodsmoke exposure. Eight subjects had peak urinary elimination of methoxyphenols within 6 h (t1/2 3-5 h), whereas one had delayed elimination. Several metrics for urinary excretion were evaluated. Analyte concentration was greatly affected by diuresis. Excretion rate and analyte concentrations normalized by creatinine gave a clearer signal and were equivalent in predictive ability. Twelve-hour average creatinine-normalized concentrations of each of the 5 methoxyphenols gave a Pearson correlation > or = 0.8 with their particle-phase concentration. The sum of urinary concentrations for the 5 methoxyphenols versus levoglucosan on personal filters gave a regression coefficient of 0.75. This sum versus PM2.5 gave a regression coefficient of 0.79. The intercept of this regression suggests that the threshold for detection of an acute exposure event would be approximately 760 microg/m3 particulate matter from woodsmoke. The signal-to-noise (12-h postexposure average/preexposure average) ranged from 1.1 to 8 for the 5 methoxyphenols. Analysis of multiple compounds provided assurance that elevations were not artifactual due to food or other products.     

Fluorescence based measurement of temperature profiles during polymer processing

We describe a novel noninvasive method to measure temperature profiles during processing. A key feature is the use of a temperature-sensitive fluorescent dye that is incorporated into the polymer resin at dopant levels. By monitoring spectral features of this dye, we can effectively measure its temperature. A focusing technique that we call “confocal fluorescent optics” then allows us to measure the temperature as a function of position into the resin. We present results of critical tests of the device. Namely we test the spatial resolution and its ability to measure a linear temperature profile in a quiescent polymer. Finally, we present the first on-line temperature profile measurements, carried out in a circular die at the exit of a twin screw extruder. Temperature gradients on the order of 5°C/mm in a polyethylene resin are observed between the outer wall and the center of the die.