On the acquisition of mnemonic skill: Application of skilled memory theory.

Skilled memory theory (W. G. Chase & K. A. Ericsson, 1981, 1982) can provide a useful theoretical framework for describing the details of performance during the acquisition of mnemonic skill, one that can point to the critical conditions necessary for the successful acquisition of mnemonic skills (in particular) and cognitive skills (in general). To provide support for this suggestion, the authors describe the results of an extended investigation of the uninstructed development of mnemonic skill in a group of normal adults. This study demonstrated that high levels of serial recall performance can be reliably developed in a group of individuals in a relatively short period of time (1 semester). In addition, the process of acquisition and the critical conditions for optimal training outcomes can be well described by the principles of skilled memory theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The de Haas-van Alphen effect and the Fermi surface of the intermetallic compound AuPb2

The de Haas-van Alphen effect has been measured in the intermetallic compound AuPb₂ (body-centered tetragonal structure) by the modulation method in fields up to 100 kG. Thirty-two frequency branches have been observed in the (100), (110), and (001) planes, and several cyclotron effective masses have been determined. The nearly-free-electron model has been used to construct a Fermi surface, which explains the large frequency branches and is compatible with the high-field magnetoresistance results of Bass, Edwards, and Schroeder. It has been possible to determine the shape of some sheets by inversion of the de Haas-van Alphen data. The lattice parameters have been determined at room temperature and at liquid helium temperature.Canada Council Fellow.     

Initial recall, reminiscence, and hypermnesia: Comment on Madigan and O'Hara (1992).

S. Madigan and R. O'Hara (see record 1992-18645-001) analyzed data from repeated free-recall experiments and concluded that the rate of item recovery across tests was related to the level of recall performance on an initial free-recall test. The authors report a reanalysis of these data along with Monte Carlo simulations that indicate the measures used by Madigan and O'Hara may have inflated the magnitude of the relation between initial recall and item recovery. The results are discussed in terms of their implications for future research investigating reminiscence and hypermnesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children and adults use lexical principles to learn new nouns.

In 2 experiments, adults and children were tested in an object-selection task that examined whether Ss would (1) map a novel word onto a previously unnamed object and (2) extend the newly learned word to another exemplar. Exp 3 was a control study. Ss overwhelmingly selected the novel object as the referent for the novel term, even though the new label was never explicitly linked to the novel object. Ss also extended the new term and allowed it to preempt yet another novel label from applying to the just-named object. The existence of several lexical principles and the power of indirect word learning is supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in phenomenological experience: States of consciousness as a function of absorption.

In Exp I, 179 female and 70 male undergraduates were used to assess the relation betwen absorption and the dimensions of consciousness monitored during the stimulus conditions of sitting quietly with eyes open, reading erotica, and relaxation-meditation. Ss were administered the Absorption and Introversion–Extraversion subscales of the Differential Personality Questionnaire. Results show almost no sex differences for the various dimensions of consciousness. Significant correlations were found between absorption and awareness and state of awareness, altered experience and meaning, perception, time sense, and body image. In Exp II, 217 female and 87 male undergraduates were used to compare differences in phenomenological state across low-, medium-, and high-absorption Ss. Results show that absorption correlated with increased and more vivid imagery, inward and absorbed attention, positive affect, decreased self-awareness, and increased alterations in state of consciousness and various aspects of subjective experience. Ss with high-absorption ability experienced a different state of consciousness during ordinary, waking consciousness that became an altered state with eye closure and a hypnoticlike induction. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of valence states of copper in copper-phosphate glasses

Phosphate glasses containing CuO with composition, [(CuO) _x (P₂O₅)_1–x ], x=0.10, 0.20, 0.25, 0.30, 0.40 and 0.50, were studied by magnetization, X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS). It was observed that compositional changes take place in going from batch to glass and these changes are more pronounced for low copper concentration. The ratio [Cu²⁺/Cu_total] as a function of x was determined from XPS and magnetization combined with RBS. The magnetization measurements suggest that more than 90% of the copper ions exist in the Cu²⁺ state in the glasses, while the XPS data show that less than 50% of the copper ions may be in the Cu²⁺ state. The low Cu²⁺ states detected by XPS may have resulted form reduction of copper ions upon exposure of the samples to X-ray radiation during measurement.Author to whom all correspondence should be addressed.     

The relevance of reliability and validity to usability testing

The authors argue that while usability testers have drawn on demonstrated practices from a variety of the social and clinical sciences in developing their methods, they have not concerned themselves with the reliability and validity of the data produced. The authors suggest that the concepts of reliability and validity are relevant to usability testing and that a concern for reliability and validity will enhance the credibility and effectiveness of usability testers     

Versatile online-offline engine for automated acquisition of high-resolution tandem mass spectra

For automated production of tandem mass spectrometric data for proteins and peptides >3 kDa at >50 000 resolution, a dual online-offline approach is presented here that improves upon standard liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategies. An integrated hardware and software infrastructure analyzes online LC-MS data and intelligently determines which targets to interrogate offline using a posteriori knowledge such as prior observation, identification, and degree of characterization. This platform represents a way to implement accurate mass inclusion and exclusion lists in the context of a proteome project, automating collection of high-resolution MS/MS data that cannot currently be acquired on a chromatographic time scale at equivalent spectral quality. For intact proteins from an acid extract of human nuclei fractionated by reversed-phase liquid chromatography (RPLC), the automated offline system generated 57 successful identifications of protein forms arising from 30 distinct genes, a substantial improvement over online LC-MS/MS using the same 12 T LTQ FT Ultra instrument. Analysis of human nuclei subjected to a shotgun Lys-C digest using the same RPLC/automated offline sampling identified 147 unique peptides containing 29 co- and post-translational modifications. Expectation values ranged from 10 (-5) to 10 (-99), allowing routine multiplexed identifications.     

Global amine and acid functional group modification of proteins

A sequential reaction methodology is employed for the complete derivatization of protein thiols, amines, and acids in high purity under denaturing conditions. Following standard thiol alkylation, protein amines are modified via reductive methylation with formaldehyde and pyridine-borane. Protein acids are subsequently amidated under buffered conditions in DMSO using the coupling reagent (7-azabenzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate. The generality of the approach is demonstrated with four proteins and with several amines yielding near-quantitative transformations as characterized by high-resolution Fourier transform mass spectrometry. The developed approach has numerous implications for protein characterization and general protein chemistry. Applications in mass spectrometry (MS) based proteomics of intact proteins (top-down MS) are explored, including the addition of stable isotopes for relative quantitation and protein identification through functional group counting. The methodology can be used for altering the physical and chemical properties of proteins, as demonstrated with amidation to modify protein isoelectric point and through derivatization with quaternary amines. Additionally, the chemistry has applications in the semisynthesis of monodisperse polymers based on protein scaffolds. We prepare proteins modified with azides and alkynes to enable further functionalization via copper(I)-catalyzed 1,3-dipolar Huisgen cycloaddition ("click") chemistry.     

Overcoming Zinc Oxide Interface Instability with a Methylammonium‐Free Perovskite for High‐Performance Solar Cells

Perovskite solar cells have achieved the highest power conversion efficiencies on metal oxide n‐type layers, including SnO₂ and TiO₂. Despite ZnO having superior optoelectronic properties to these metal oxides, such as improved transmittance, higher conductivity, and closer conduction band alignment to methylammonium (MA)PbI₃, ZnO is largely overlooked due to a chemical instability when in contact with metal halide perovskites, which leads to rapid decomposition of the perovskite. While surface passivation techniques have somewhat mitigated this instability, investigations as to whether all metal halide perovskites exhibit this instability with ZnO are yet to be undertaken. Experimental methods to elucidate the degradation mechanisms at ZnO–MAPbI₃ interfaces are developed. By substituting MA with formamidinium (FA) and cesium (Cs), the stability of the perovskite–ZnO interface is greatly enhanced and it is found that stability compares favorably with SnO₂‐based devices after high‐intensity UV irradiation and 85 °C thermal stressing. For devices comprising FA‐ and Cs‐based metal halide perovskite absorber layers on ZnO, a 21.1% scanned power conversion efficiency and 18% steady‐state power output are achieved. This work demonstrates that ZnO appears to be as feasible an n‐type charge extraction layer as SnO₂, with many foreseeable advantages, provided that MA cations are avoided.