Cognitive stimulation and problem presentation in idea-generating groups.

One technique that may facilitate group brainstorming is decomposition of the task so that categories of the problem are considered one at a time rather than simultaneously (A. R. Dennis, J. S. Valacich, T. Connolly, & B. E. Wynne, 1996). Two studies examined this possibility for both solitary and interactive brainstorming in which major categories of a brainstorming problem were presented simultaneously or sequentially. In the 1st study, participants in the sequential presentation condition generated more ideas than did those in the simultaneous condition in both the individual and the group conditions. In the 2nd study, individuals exposed to either a high number or low number of idea categories demonstrated enhanced performance. Simulations of the data demonstrated that the results were consistent with an associative memory model of the idea generation process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auxiliary equations for the determination of specific exergy revenues

Thermoeconomics allows the specific costs (the costs per unit exergy) associated with exergy streams to be determined within, and at the boundaries of, energy systems. These costs are determined through the simultaneous solution of monetary balances and auxiliary equations, with the values of the primary fuel and capital costs known. The methodology for determining the auxiliary equations, when product costs are to be calculated from known fuel and capital costs, has been formulated by Lazzaretto and Tsatsaronis. These costs and other thermoeconomic variables have been shown to have utility in the optimization of energy systems. In most applications, this has been applied to systems with a specified output and variable fuel input. The goal in the optimization of these systems is to minimize product costs; for a given output with given product price(s), this is equivalent to maximizing profit. However, some practical systems, such as a combined-cycle power plant, have an essentially fixed fuel input. In these cases, capital cost is traded against power output, and profit is maximized by taking the difference of the products times their prices and the capital costs. With a known price of the product, a value fundamentally different than a specific cost is calculated. In this paper, these values are called “specific revenues”. Owing to their difference in nature from specific costs, specific revenues require different auxiliary equations. Here, the differences between revenues and costs are explained, principles are given for writing the proper governing equations and both revenues and costs are given for a simple example system. Additionally, some suggestions as to how these specific revenues may aid in system optimization are given.     

Formation of thiazolines within the peptide chain during heating of proteins

  L-2-Methyl-4-carboxy-thiazoline was isolated by ion-exchange chromatography and RP-HPLC from heated solutions of N-acetyl-L-cysteine. The structure was established by NMR-spectroscopy. The formation of thiazolines during the heating of cysteine-containing peptides (glycyl-glycyl-cysteine, glycyl-cysteinyl-glycine, glutathione) was observed by UV and NMR-spectroscopy and measured by cation-exchange chromatography. The rate of formation was dependent on the pH, the water activity and the temperature. In comparison with untreated samples, a characteristic increase of absorption at 260 nm in heated proteins (β-lactoglobulin, ovalbumin) was noticed. Using NMR-spectroscopy [two-dimensional: hetero nuclear multiple quantum coherence (HMQC) and total correlated spectroscopy (TOCSY)] the formation of thiazolines within heated proteins (β-lactoglobulin, egg white albumin and bovine serum albumin) could be demonstrated unequivocally. The signals of the methine-proton of thiazolines as well as the coupling constants of the thiazoline protons are very characteristic and not overlaid by signals of protein-bound amino acids. Received: 26 April 1996 / Revised version: 30 July 1996     

Impact behaviour of PELE projectiles perforating thin target plates

The first experiments with a penetrator with enhanced lateral efficiency (PELE) were carried out in 1996. The unusual behaviour of the penetrator as it perforates a target can generally be described in three main stages. In the first stage the different kinetic energies of the jacket and the filling lead to the enclosure of the filling material. This induces a pressure rise in the filling, which dilates the surrounding jacket in the second stage. During the last stage the high-density jacket breaks into pieces. When a thin target, as in our case, is perforated, a fourth stage must be added to the other three. This new stage describes the interaction between the filling and the plug, which is produced during the impact. For the lateral efficiency of the PELE, the second stage is the important one. The behaviour in this stage (pressure build-up and radial expansion of the jacket) is dominated by only a few physical parameters. For weak shock waves, these parameters are determined by theoretical consideration. A number of experiments were carried out in the velocity range between 900 and 3000 m/s in order to obtain an experimental database. In the last section a comparison between the physical model and experimental data gives a short outline of the complex impact behaviour of the PELE projectile. The physical model and the experimental data are in good agreement for impact velocities under 1400 m/s. For higher velocities causing stronger shock waves, the theory has to be modified; but the set of physical parameters influencing the terminal ballistic behaviour of PELE remains valid.     

User involvement and user satisfaction with information-seeking activity

This paper presents the result of an empirical study that investigates user involvement and user satisfaction in the context of information-seeking activity. This study adopts the definition of user involvement as the psychological state of the importance and personal relevance that users attach to a given system. Following Celsi and Olson, intrinsic and situational motivators were considered as two antecedents of user involvement. These two types of motivator were treated as formative exogenous variables, while user involvement and user satisfaction were treated as reflective mediating endogenous variable and final endogenous variable, respectively. Five hypotheses were proposed, and all were supported by the data from a laboratory experiment. This paper also reports two other interesting findings. First, intrinsic motivators have a stronger positive effect on user involvement than situational motivators have. Second, situational motivators have a stronger positive effect on user satisfaction than intrinsic motivators have. The discussion part explains these interesting findings.     

Enterolithiasis, refractory anemia, and strictures of Crohn''s disease

It has been recently shown that NGF is not only involved in the survival and development of sympathetic and neural crest-derived sensory neurons, but also in some mechanisms of the immune system. For this reason, we studied the content of NGF in CSF samples from patients with diseases in which neuroimmunological mechanisms seem to be involved (multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer disease, chronic relapsing polyradiculoneuritis, Guillain-Barré syndrome, and tumors of the nervous system), as well as from a number of normal control subjects. We setup an ELISA aimed at the beta subunit of NGF, obtaining good validation tests and a detection limit of 28 pg beta NGF per ml. None of the samples was found to contain detectable levels of NGF and, when a concentration method for sample enrichment was used, only one patient was NGF-positive. This suggests that NGF is probably not involved in the neuroimmunological mechanisms underlying some inflammatory and degenerative diseases of the nervous system.     

Dispersion control in a 100-kHz-repetition-rate 35-fs Ti:sapphire regenerative amplifier system

Presents a 100-kHz femtosecond amplifier system delivering pulses with a duration of 35 fs and an energy of 7 /spl mu/J. The system does not include a stretcher, since the large amount of dispersion accumulated during the amplification process is sufficient to prevent self-focusing. Compensation in approximately all orders is achieved through a combination of a prism compressor, chirped mirrors, and a liquid-crystal modulator, allowing the amplified pulses to be shortened to nearly the bandwidth limit.     

Acquired colour deficiency in patients with Parkinson's disease

The blue cone pathway is reported to be affected early in Parkinson's disease (PD) and acquired type three (tritan) defects may occur. Sixty-one patients attending a treatment and rehabilitation centre for PD were examined with clinical colour vision tests. Seven of 13 patients, for whom the diagnosis of PD was equivocal or who had other medical conditions, were identified as having tritan colour deficiency. Results for the remaining 44 PD patients were compared with 40 age matched controls. Ten PD patients (22.7%) had tritan defects. Tritan defects were not found in the control group but performance on some tests was age related. We conclude that clinical tests for tritan colour deficiency are unlikely to be helpful in identifying PD.     

Characterization and functional analysis of the cis-autoproteolysis active center of glycosylasparaginase

Glycosylasparaginase is an N-terminal nucleophile hydrolase and is activated by intramolecular autoproteolytic processing. This cis-autoproteolysis possesses unique kinetics characterized by a reversible N-O acyl rearrangement step in the processing. Arg-180 and Asp-183, involved in binding of the substrate in the mature enzyme, are also involved in binding of free amino acids in the partially formed substrate pocket on certain mutant precursors. This binding site is sequestered in the wild-type precursor. Binding of free amino acids on mutant precursors can either inhibit or accelerate their processing, depending on the individual mutants and amino acids. The polypeptide sequence at the processing site, which is highly conserved, adopts a special conformation. Asp-151 is essential for maintaining this conformation, possibly by anchoring its side chain into the partially formed substrate pocket through interaction with Arg-180. The reactive nucleophile Thr-152 is activated not only by deprotonation by His-150 but also by interaction with Thr-170, suggesting a His-Thr-Thr active triad for the autoproteolysis.     

Some observations of entropy extrema in fluid flow

This paper makes observations regarding the extremization of entropy’s production, and therefore available energy’s destruction, in processes. The “case studies” given here were performed to gain insight, with a long-term goal of discovering a general extremization principle in thermodynamics (for example, a variational principle similar to Hamilton’s principle, representing “the” equation of motion). The majority of these “case studies” are processes for which there are well known mathematical models. In several of them, entropy extremization has been recognized before.