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To assess allocation of attention by music teachers with different levels of experience and expertise, we recruited five participant flautists: an artist teacher, two graduate students, and two undergraduates, all of whom observed nine brief video recordings of flute, clarinet, and saxophone players; a juggler; a baseball batter; and a ballerina. We tracked participants’ gaze using wearable eye-tracking hardware and software, and we analyzed the targets and durations of over 1,300 visual fixations and the paths of participants’ eye movements while observing the videos. The gaze behavior of the artist teacher and one of the graduate students, when they observed flute playing, was much like that of the experts in other domains of human experience. These two participants’ fixations were longer than those of the other three participants, and the sequence of fixation targets reflected a hierarchical prioritization of the fundamentals of flute playing. These same features were not apparent when these same two participants observed the other videos, and they were not observed in the gaze behavior of the other three participants in any of the videos observed. The results of this study demonstrate that allocation of attention, as indicated by gaze behavior, is reflective of expertise in music teaching as it is in other domains.

We asked school- and college-aged instrumentalists ( N = 32) to imagine an ideal performance of a brief passage of music, record a performance of the passage, and describe discrepancies they noticed between their imagined and actual performances. The more experienced participants took at least as much time to imagine their idealized performances as it took to perform them; less experienced participants took less time to imagine what they were about to play. There were no differences among experience levels in the numbers or types of discrepancies identified. The differences between more and less experienced participants were also evident in a subsequent practice period. More experienced musicians’ practice included more frequent moments of pause, whereas school-aged participants seldom paused and tended to address performance issues other than those identified in their commentaries.

In two experiments we examined the extent to which musicians identify discrepancies between their intentions and their playing during individual practice. In the first experiment, 60 musicians representing four levels of skill development practiced a familiar piece from their own repertoire for 5 min while being audio recorded. They then listened to their recorded practice and pressed a computer key to mark moments of discrepancy between what they had intended while practicing and what they heard on the recordings. The mean rates of key presses did not differ among the four participant groups, although there were large within-group variances. In the second experiment, 13 high school and 11 expert participants from Experiment 1 returned 2 years later and listened to their original recordings, this time marking moments of discrepancy between what would be their current intentions and what they heard on their 2-year-old recordings. High school participants marked significantly more discrepancies after 2 years than they had in Experiment 1, but the mean rate of key presses among experts did not increase between Experiment 1 and Experiment 2. These results support the notion that the precision of performance goals and the acuity of perceptual discrimination are central features of musical expertise.

We measured the extent to which motor skill performance is advantaged by break intervals that include varied types of cognitive activity interposed early in a training session, directly comparing the performances of musicians and nonmusicians. Participants ( N = 118; 59 music majors, 59 nonmusicians) learned a 5-element keypress sequence on a digital piano during 12 min training sessions. Participants in three conditions took a 5 min break after 3 min of practice, and either practiced a new 5-element sequence (Break-motor), memorized word pairs (Break-word pair), or conversed with the proctor (Break-talk). Those in the fourth condition took no break (No-break). Participants were tested 12 hr later, following a night of sleep. Participants made significant performance gains across training and test, but musicians significantly outperformed nonmusicians at all timepoints. Nonmusicians made greater percentage gains than did musicians over the 5 min break interval and overnight, and participants in the Break-motor condition made significantly smaller gains over the 5 min break interval than did participants in the Break-talk and Break-word pair conditions. These results demonstrate that tasks involving declarative memories do not diminish performance enhancements that accrue during breaks early in motor skill practice, but these enhancements can be inhibited by engaging in competing motor tasks.

The development of accurate potentials for computational simulations has been an active area of research. Our group has been involved in the development of the Gaussian electrostatic model (GEM), a force field based on molecular densities. The philosophy of GEM is based on the pioneering work of N. Gresh and co-workers of the reproduction of individual inter-molecular interaction components obtained from quantum mechanical (QM) energy decomposition analysis (EDA). The molecular densities used in GEM are represented by fitting accurate QM molecular densities using auxiliary basis sets (comprised of Hermite Gaussians). The use of these molecular densities results in the need to evaluate a large number of Gaussian integrals. We have previously shown that the particle-mesh Ewald (PME), and fast Fourier Poisson (FFP) methods can be used for efficiently evaluating these types of integrals. Here, we present the latest parameterization of GEM* and its application for an extensive study of PME and FFP for molecular dynamics (MD) simulations using a hybrid version of our potential, GEM*. The temperature dependence of various bulk properties is presented and discussed, as well as the effect of various parameters affecting the performance/accuracy of both methods.

Our manuscript describes the implementation and performance of Ewald-based approaches for the calculation of Gaussian integrals in the pmemd.gem code as released in the AMBER18 suite, as well as a new parametrization of our density-based Gaussian Electrostatic Model* (GEM*) force field using CCSD(T)/CBS//SAPT2+3/aug-cc-pVTZ data for the fit.

Taking long-range electrostatic effects into account in classical and hybrid quantum mechanics–molecular mechanics (QM/MM) simulations is necessary for an accurate description of the system under study. We have recently developed a method, termed long-range electrostatic corrections (LREC), for monopolar QM/MM calculations. Here, we present an extension of LREC for multipolar/polarizable QM/MM simulations within the LICHEM software package. Reaction barriers and QM–MM interaction energies converge with a LREC cutoff between 20 and 25 A, in agreement with our previous results. Additionally, the LREC approach for the QM–MM interactions can be smoothly combined with standard shifting or Ewald summation methods in the MM calculations. We recommend the use of QM(LREC)/MM(PME), where the QM region is treated with LREC and the MM region is treated with particle mesh Ewald (PME) summation. This combination is an excellent compromise between simplicity, speed, and accuracy for large QM/MM simulations.

This study was designed to investigate the extent to which the presentation of an auditory model prior to learning a novel melody affects performance during active practice and the overnight consolidation of procedural memory. During evening training sessions, 32 nonpianist musicians practiced a 13-note keyboard melody with their left (nondominant) hand in twelve 30-s practice intervals separated by 30-s rest intervals. Participants were instructed to play the sequence “as quickly, accurately, and evenly as possible.” Approximately half the participants, prior to the first practice interval, listened to 10 repetitions of the target melody played at 552 tones per minute (half note = 138). All participants were tested on the target melody the following morning, approximately 12 hr after training, in three 30-s blocks separated by 30-s rest intervals. Performance was measured in terms of the mean number of correct key presses per 30-s block (CKP/B). Consistent with previous research, participants made considerable improvements in CKP/B during the evening training sessions and between the end of training and the morning test sessions. Learners who listened to the model made significantly larger gains in performance during training and between the end of training and test than did those who did not hear the model.

During evening practice sessions, 32 nonpianist musicians learned a short melody on piano, and then either learned a second short piano melody, learned a difficult unfamiliar piece on their principal instruments, practiced familiar material on their principal instruments, or engaged in no other music-related motor behavior prior to sleep; practice on the target melody was limited in terms of time and number of repetitions. All participants returned the next morning and were tested on their performance of the target piano melody. Previous research has revealed overnight enhancement of skills as a result of sleep. In the current study, however, our participants showed significant decrements in performance between evening training and morning test, though the extent of the decrements varied. We speculate that the lack of overnight improvements may have resulted from our regulating participants’ practice of the target melody during the training sessions and that strict, limited practice protocols may interfere with consolidation-based memory enhancement.

Skillful teachers have developed the ability to take learners from the first conception of a goal to its accomplishment in shorter and shorter periods of time, with fewer and fewer errors on the le...

To test the extent to which learners performing a simple keyboard passage would be affected by directing their focus of attention to different aspects of their movements, 16 music majors performed a brief keyboard passage under each of four focus conditions arranged in a counterbalanced design—a total of 64 experimental sessions. As they performed the test passage, participants were directed to focus their attention on either their fingers, the piano keys, the piano hammers, or the sound produced. Complete MIDI data for all responses were digitally recorded by software written specifically for this experiment. Consistent with findings obtained in tests of other physical skills, the results show that performance was most accurate and generalizable when participants focused on the effects their movements produced rather than on the movements themselves, and that the more distal the focus of attention, the more accurate the motor control.

The putative structure of the Tissue Factor/Factor VIIa/Factor Xa (TF/FVIIa/FXa) ternary complex is reconsidered. Two independently derived docking models proposed in 2003 (one for our laboratory: CHeA and one from the Scripps laboratory: Ss) are dynamically equilibrated for over 10 ns in an electrically neutral solution using all-atom molecular dynamics. Although the dynamical models (CHeB and Se) differ in atomic detail, there are similarities in that TF is found to interact with the gamma-carboxyglutamic acid (Gla) and Epidermal Growth Factor-like 1 (EGF-1) domains of FXa, and FVIIa is found to interact with the Gla, EGF-2 and serine protease (SP) domains of FXa in both models. FVIIa does not interact with the FXa EGF-1 domain in Se and the EGF domains of FVIIa do not interact with FXa in the CHeB. Both models are consistent with experimentally suggested contacts between the SP domain of FVIIa with the EGF-2 and SP domains of FXa.

In two experiments, we tested the extent to which overnight procedural memory consolidation is affected by extended rest breaks during training. In the first experiment, nonmusicians practiced a 5-element keypress sequence with their nondominant hand in 12 30-s practice intervals separated by 30-s pauses. In the second experiment, nonpianist musicians practiced a 13-note keyboard melody using the same procedures. In both experiments, approximately one-third of the subjects took a 5-min break after the first three blocks of practice; another third took a break after nine blocks of practice; the remaining participants did not take an extended break. All were trained in the evening and were retested the following morning. Participants in both experiments made dramatic improvements over the course of the training and retest sessions, and participants who took an extended rest break early in practice made the largest gains in performance between the end of training and the beginning of retest.

Protein Z-dependent protease inhibitor (ZPI) and antithrombin III (AT3) are members of the serpin superfamily of protease inhibitors that inhibit factor Xa (FXa) and other proteases in the coagulation pathway. While experimental structural information is available for the interaction of AT3 with FXa, at present there is no structural data regarding the interaction of ZPI with FXa, and the precise role of this interaction in the blood coagulation pathway is poorly understood. In an effort to gain a structural understanding of this system, we have built a solvent equilibrated three-dimensional structural model of the Michaelis complex of human ZPI/FXa using homology modeling, protein–protein docking and molecular dynamics simulation methods. Preliminary analysis of interactions at the complex interface from our simulations suggests that the interactions of the reactive center loop (RCL) and the exosite surface of ZPI with FXa are similar to those observed from X-ray crystal structure-based simulations of AT3/FXa. However, detailed comparison of our modeled structure of ZPI/FXa with that of AT3/FXa points to differences in interaction specificity at the reactive center and in the stability of the inhibitory complex, due to the presence of a tyrosine residue at the P1 position in ZPI, instead of the P1 arginine residue in AT3. The modeled structure also shows specific structural differences between AT3 and ZPI in the heparin-binding and flexible N-terminal tail regions. Our structural model of ZPI/FXa is also compatible with available experimental information regarding the importance for the inhibitory action of certain basic residues in FXa.

We report a serious problem associated with a number of current implementations of Andersen and Langevin dynamics algorithms. When long simulations are run in many segments, it is sometimes possible to have a repeating sequence of pseudorandom numbers enter the calcuation. We show that, if the sequence repeats rapidly, the resulting artifacts can quickly denature biomolecules and are then easily detectable. However, if the sequence repeats less frequently, the artifacts become subtle and easily overlooked. We derive a formula for the underlying cause of artifacts in the case of the Langevin thermostat, and find it vanishes slowly as the inverse square root of the number of time steps per simulation segment. Numerous examples of simulation artifacts are presented, including dissociation of a tetrameric protein after 110 ns of dynamics, reductions in atomic fluctuations for a small protein in implicit solvent, altered thermodynamic properties of a box of water molecules, and changes in the transition free energies between dihedral angle conformations. Finally, in the case of strong thermocoupling, we link the observed artifacts to previous work in nonlinear dynamics and show that it is possible to drive a 20-residue, implicitly solvated protein into periodic trajectories if the thermostat is not used properly. Our findings should help other investigators re-evaluate simulations that may have been corrupted and obtain more accurate results.

Although protein Z (PZ) has a domain arrangement similar to the essential coagulation proteins FVII, FIX, FX, and protein C, its serine protease (SP)-like domain is incomplete and does not exhibit proteolytic activity. We have generated a trial sequence of putative activated protein Z (PZa) by identifying amino acid mutations in the SP-like domain that might reasonably resurrect the serine protease catalytic activity of PZ. The structure of the activated form was then modeled based on the proposed sequence using homology modeling and solvent-equilibrated molecular dynamics simulations. In silico docking of inhibitors of FVIIa and FXa to the putative active site of equilibrated PZa, along with structural comparison with its homologous proteins, suggest that the designed PZa can possibly act as a serine protease.

Summary. Background: The prothrombinase complex consists of factor Xa, FVa, calcium ions, and phospholipid membrane. The prothrombinase complex plays a key role in the blood coagulation process. Objective: To derive solvent-equilibrated models of human FVa and the prothrombinase complex. Methods: Several modeling techniques have been employed, including homology modeling, protein–protein docking, and molecular dynamics simulation methods, to build the structural models. Results and conclusions: We found, upon simulation, a possibly significant shift towards planarity of the five FVa domains. To estimate a prothrombinase structure, we docked an FXa model to the equilibrated FVa model using experimental data as docking filters. We found that simulation of the docked complex led to some changes in the protein–protein contacts, but not buried surface area, as compared to the initial docking model. Possible locations of prothrombin binding to prothrombinase are indicated.

GEM*, a force field that combines Coulomb and Exchange terms calculated with Hermite Gaussians with the polarization, bonded, and modified van der Waals terms from AMOEBA is presented. GEM* is tested on an initial water model fitted at the same level as AMOEBA. The integrals required for the evaluation of the intermolecular Coulomb interactions are efficiently evaluated by means of reciprocal space methods. The GEM* water model is tested by comparing energies and forces for a series of water oligomers and MD simulations. Timings for GEM* compared to AMOEBA are presented and discussed.

A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 A cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

Using two sequential key press sequences, we tested the extent to which subjects' performance on a digital piano keyboard changed between the end of training and retest on subsequent days. We found consistent, significant improvements attributable to sleep-based consolidation effects, indicating that learning continued after the cessation of practice during both the first and second nights of sleep following training. When subjects briefly recalled a learned sequence 1 day after training and then immediately learned a second, similar sequence, there were no observable improvements in subjects' performance of the first sequence after the second night of sleep. We discuss our results in relation to similar findings in neuroscience and cognition.

The X-ray crystal structure of γ-carboxyglutamic acid (Gla) domains is well-established. These domains are stable to long all-atom simulations in explicit solvent. Here we extend a prior simulation on the Gla domain of factor VIIa, an essential vitamin K-dependent protein involved in the initiation of blood coagulation, to ∼20 ns in order to establish a reference point. We also subject this domain to a set of rational environmental changes using molecular dynamics techniques that accommodate long-range electrostatics accurately: (a) we move the seven bound calcium ions to >17.5 A from any Gla residue and then simulate for 25 ns, and (b) in a separate calculation, we change all of the calcium ions to sodium ions and simulate for 20 ns. For both perturbed systems, the N-terminus chelation complex is initially greatly weakened, leading to increased motion of the ω loop (residues 1-11). In technique a, most calcium ions return to the preperturbation coordinating units within the time scale of the simulation. We track and display the sequence of calcium ion rebinding. The response of this complex, nonstandard system to the perturbations as estimated by accurate all-atom dynamics gives new details on the degree of sampling in early refolding events.

We tested whether observers' perceptions of private lessons are affected by the type of verbalizations used by teachers to make corrections in student performance. We compared verbal corrections that were expressed as directive statements (i.e., specific directions to change some aspect of performance in a subsequent trial) and verbal corrections expressed as negative feedback statements (i.e., negative evaluations of student performance in a preceding performance trial). Participants viewed two videotaped private lessons. In one lesson, all corrections of student performance errors were expressed as directions to change some aspect of performance in the subsequent trial. In the other lesson, all corrections were expressed as negative feedback statements followed by a direction to play again. Subjects responded using a paper-and-pencil questionnaire with 10 statements about the teacher and student in each lesson. There were no meaningful differences in subjects' responses between the two lessons, both of which were rated highly positively. Asked to cite differences observed between the two lessons, few subjects identified any aspect of the teacher's feedback.

To compare two common measures of overall effect in music, we assessed listeners' perceptions of musical intensity in nine excerpts of orchestral music using two assessment procedures: (1) recording subjects' moment-to-moment responses as they listened to each excerpt and then averaging each subjects ratings to obtain a measure of overall intensity, and (2) recording subjects' post hoc ratings of intensity at the conclusion of each excerpt. The results illustrate the nonequivalence of these two measures of overall effect. Internal consistency was high for both measures, but the post hoc ratings were generally higher than mean ratings in both between- and within-subject comparisons. The magnitude of the differences between the two measures varied depending upon the nature of the changes in each stimulus. The results obtained in this investigation are nearly identical to those obtained by Brittin and Duke (1997a, 1997b) and suggest that it is inadvisable to interpret arithmetic means of momentary responses as indicators of subjects' perceptions of overall effect.

The investigation described in this report documents the types of behavior that take place in the studios of nationally and/or regionally acclaimed string teachers whose instruction is based on the principles of Shinichi Suzuki. The specific focus of the investigation was the time allocated to different aspects of teacher, student, and parent behavior as teachers and students worked to improve students' playing of repertoire in the context of individual lessons. The study also examined the relationships among various student characteristics and the lesson behavior observed. Each of 29 string teachers was observed teaching two or three different students across three consecutive lessons—a total of 246 lessons. A unique aspect of the investigation was the enlistment of 13 expert string pedagogues who were trained to evaluate videotaped instruction using systematic observation procedures designed specifically for this project. The observation procedures were designed to address specific research questions that had been identified at the International Suzuki Institute Research Symposium (Aber, 1990).

The present study was designed to compare the effects of negative feedback statements and specific directives in music performance instruction. Twenty-five college undergraduates and 25 fifth- and sixth-grade students were taught by rote to play on soprano recorder an accompaniment part to the theme to Sesame Street. All subjects were taught in individual lessons by the same teacher. In approximately half the lessons at each age level, the teacher communicated corrective information through negative feedback statements. In the remaining lessons, the teacher communicated corrective information through specific directives. Results indicate that subjects' attitudes and performance achievement were unaffected by the experimental conditions. All subjects expressed positive attitudes about the experience, and the time required to reach the final performance goal and the quality of student performance were not different between the group receiving negative feedback and the group receiving directives.

The present study was designed to assess novice teachers* perceptions of timing in music instruction and to identify the aspects of timing that are associated with positive perceptions of instructional pacing. We selected eight 1-3-minute excerpts from teaching-practicum videotapes of four novice teachers teaching in a choral rehearsal, a band rehearsal, and two elementary music classrooms. Each teacher appeared in two excerpts that differed with regard to the pace of instruction depicted in each. Novice teachers (N = 44) viewed the videotaped excerpts and evaluated the pace of instruction along six semantic differential scales: fast—slow; appropriate—inappropriate; tense—relaxed; smooth-uneven; too fast-too slow; good-bad. Subjects discriminated among the faster and slower examples on five of the six evaluation dimensions, and among teachers on all six dimensions. Subjects rated the pace of instruction more positively when the rates of student performance episodes and teacher activity episodes were higher rather than lower, and when the mean durations of teacher and student activity were shorter rather than longer. These variables may function as operational measures of the pace of instruction in music performance.