The effect of task complexity on the human learning function

This experimental study analysed the effects of the complexity (entropy) of a repetitive tusk on the human looming function for the task. The results from 20 subjects revealed that the task entropy had a significant influence on the relationship between the performance (cycle time) and practice (the number of repetitions or cycle number). The model parameters for this relationship were found to be significantly and linearly related to the task entropy, the nominal rate of which varied within the maximum range of 0·9·to 6.1 bits/s     

Velocity fluctuation reduction in vector Doppler ultrasound using a hybrid single/dual-beam algorithm

In order to reduce the fluctuations in the velocity magnitude estimate, we propose a modification to the standard algorithm for reconstructing the (two component) vector velocity from the measured Doppler shifts in two directions. This uses the standard dual-beam algorithm, combined with temporal smoothing, to find only the velocity angle, then uses the single-beam algorithm to estimate the velocity magnitude. We present initial data showing the significant reduction in velocity estimate fluctuation that this hybrid method achieves compared to the standard algorithm.     

Characterization of dihydrofolate reductase genes from trimethoprim-susceptible and trimethoprim-resistant strains of Enterococcus faecalis

PURPOSE: To understand the molecular mechanisms involved in protein-methylidene malonate 2.1.2 polymer interactions. METHODS: To assess the importance of electrostatic forces in polymer-protein interactions use was made of HSA and its derivatives, which were anionized by succinylation and aconitylation. Surface plasmon resonance measurements, using the three HSA molecules as immobilized ligands and polymer nanoparticles as analytes in the liquid phase, allowed the determination of initial kinetic constants and affinity constants at equilibrium at two different temperatures. RESULTS: Saturation of binding for the three proteins occurred at approximately 900 protein molecules/nanoparticle. The apparent affinity decreased with increasing electronegativity of the proteins. Surface plasmon resonance measurement of proteins, covalently linked to the chip matrix, showed a high affinity for the nanoparticles (K(A) approximately 10(10) M(-1) and confirmed the moderate decrease of affinity with increasing electronegativity of the modified albumins. Measurements at 25 and 37 degrees C showed no significant increase in the albumin-nanoparticle interactions. Dissociation of the proteins from the nanoparticles could only be realized with chaotropic salt solutions. CONCLUSIONS: These results suggest the molecular forces initiating the protein-nanoparticle interactions are mainly of electrostatic nature followed by stabilization by hydrophobic forces. The high affinity confirms the nanoparticles as excellent carriers for protein delivery.     

Variations of glucose, fructose, sorbite and electrolyte concentration following intravenous or intraperitoneal administration of sorbite-electrolyte solution to cattle and sheep

Different quantities of sorbite-electrolyte solution were intravenously administered to eight heads of cattle and four heads of sheep (application values being 50 g sorbite, 0.3049 g MgCl2-6H2O, 0.3728 g KCl, 0.5477 g CaCl2-6H2O, 5.265 g NaCl, 6.804 g sodium acetate-3H2O with 1,000 ml distilled water). Different rises of sorbite, fructose, and glucose were recorded from the blood plasma. Certain manifestations of incompatibility and intolerance phenomena were observed, among them increase of cardiorespiratory activity and muscular tremor. Those findings were obtained primarily from animals which exhibited also strong rise in glucose concentration. One of the sheep died. Larger quantities of solution (2,000 ml or 4,000 ml) were intraperitoneally applied to ten heads of cattle and tolerated by them with no reaction. Sorbite in blood plasma usually reached its maximum two or three hours from application, however, without any rise of fructose or glucose. Slow drip infusion or intraperitoneal infusion are the techniques recommended for application of the above sorbite-electrolyte solution to ruminants.