Description: This article discusses the discourse variations between usability tests and usability reports. Abstract: While usability evaluation and usability testing has become an important tool in artifact assessment, little is known about what happens to usability data as it moves from usability session to usability report. In this ethnographic case study, the author investigates the variations in the language used by usability participants in user-based usability testing sessions as compared to the language used by novice usability testers in their oral reports of that usability testing session. In these comparative discourse analyses, the author assesses the consistency and continuity of the usability testing data within the purview of the individual testers conducting "do-it-yourself" usability testing. This case study of a limited population suggests that findings in oral usability reports may or may not be substantiated in the evaluations themselves, that explicit or latent biases may affect the presentation of the findings in the report, and that broader investigations, both in terms of populations and methodologies, are warranted.

Description: This article discusses the selectivity and mechanism of hydrogen atom transfer by an isolable imidoiron (III) complex. In the literature, iron-oxo complexes have been isolated and their hydrogen atom transfer (HAT) reactions have been studied in detail. Iron-imido complexes have been isolated more recently, and the community needs experimental evaluations of the mechanism of HAT from late-metal imido species. The authors report a mechanistic study of HAT by an isolable iron (III) imido complex, LᴹᵉFeNAd (Lᴹᵉ = bulky β-diketiminate ligand, 2,4-bis(2,6-diisopropylphenylimido)pentyl; Ad = 1-adamantyl). HAT is preceded by binding of tert-butylpyridine (ᵗBupy) to form a reactive four-coordinate intermediate LᴹᵉFe(NAd)(ᵗBupy), as shown by equilibrium and kinetic studies. In the HAT step, very large substrate H/D kinetic isotope effects around 100 are consistent with C-H bond cleavage. The elementary HAT rate constant is increased by electron-donating groups on the pyridine additive, and by a more polar medium. When combined with the faster rate of HAT from indene versus cyclohexadiene, this trend is consistent with H⁺ transfer character in the HAT transition state. The increase in HAT rate in the presence of ᵗBupy may be explained by a combination of electronic (weaker Fe=N π-bonding) and thermodynamic (more exothermic HAT) effects. Most importantly, HAT ...

Description: This article discusses the enthalpy of solvation correlations for organic solutes and gases dissolved in 1-propanol and tetrahydrofuran. Abstract: Data have been assembled from the published literature on the enthalpies of solvation for 103 organic vapors and gaseous solutes in 1-propanol and for 86 gaseous compounds in tetrahydrofuran. It is shown that an Abraham solvation equation with five descriptors can be used to correlate the experimental solvation enthalpies to within standard deviations of 2.35 kJ/mole and 2.10 kJ/mole for 1-propanol and tetrahydrofuran, respectively. The derived correlations provide very accurate mathematical descriptions of the measured enthalpy of solvation data at 298 K, which in the case of 1-propanol span a range of 119 kJ/mole. Division of the experimental values into a training set and a test set shows that there is no bias in predictions, and that the predictive capability of the correlations is better than 3.5 kJ/mole.

Description: In this paper, the authors explore the task of automatic text processing applied to collections of historical newspapers, with the aim of assisting historical research. In particular, in this first stage of the project, the authors experiment with the use of topical models as a means to identify potential issues of interest for historians.

Description: In this article, the authors study a decision making model in a condition where it is equivalent to the two-dimensional Ising model, and the authors show that at the onset of phase transition it generates temporal complexity, namely, nonstationary and nonergodic fluctuations. The authors argue that this is a general property of criticality, thereby opening the door to the application of the recently discovered phenomenon of complexity matching: For an efficient transfer of information to occur, a perturbing complex network must share the same temporal complexity as the perturbed complex network.