Male Peer Modeling in the Kindergarten Music Classroom

The purpose of this action research study was to design, implement, and refine an approach to using male peer modeling in Kindergarten general music. Research questions investigated the male kindergarten students’ and peer models’ descriptions of the interactions, my perceptions of the effects of the peer-modeling process on both groups of students, the students’ parents’ perceptions of the effects of the process, and whether male peer modeling affected both the older and younger boys’ perceptions of singing. Two sixth grade peer models interacted with and taught songs to kindergarten students in two different classes throughout two action research cycles, switching between the two cycles. Data was collected through observation and interview. I transcribed parents’ emails and my teacher-researcher journal. I analyzed my teacher-researcher journal, video footage, and interviews for themes. I transcribed and coded the interviews between the sixth grade boys and myself and between the sixth grade boys and the Kindergarten students. The three most interesting themes which emerged included the peer models’ relationships with the Kindergarten students, the peer models’ vocal quality, and the anomaly of a male elementary school music teacher.Master of ArtsMusic EducationUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/134323/1/Warzecha-Male_Peer_Modeling_in_the_Kindergarten_Music_Classroom.pd

Noise in neurons is message-dependent

Neuronal responses are conspicuously variable. We focus on one particular aspect of that variability: the precision of action potential timing. We show that for common models of noisy spike generation, elementary considerations imply that such variability is a function of the input, and can be made arbitrarily large or small by a suitable choice of inputs. Our considerations are expected to extend to virtually any mechanism of spike generation, and we illustrate them with data from the visual pathway. Thus, a simplification usually made in the application of information theory to neural processing is violated: noise {\sl is not independent of the message}. However, we also show the existence of {\sl error-correcting} topologies, which can achieve better timing reliability than their components.Comment: 6 pages,6 figures. Proceedings of the National Academy of Sciences (in press

Effects of a bath composition on aluminium loss during Ti-Al alloy smelting in a vacuum induction furnace

In the paper, results of a kinetic analysis of aluminium evaporation from binary Ti-Al alloys during their smelting in a vacuum induction furnace are presented

Cathodoluminescence studies of chevron features in semi-polar (1122) InGaN/GaN multiple quantum well structures

Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural, and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well structure, and an amber-emitting light-emitting diode. Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the quantum wells (QWs) in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current. Overall, these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices

Oxcarbazepine form III : observation of twisted habit in crystals of an elusive pharmaceutical polymorph

Crystals exhibiting twisted habit have been observed at the nanoscale, mesoscale, and macroscale and pose challenges with respect to structural characterisation because of their lack of long-range translational symmetry [1]. Crystal structure prediction (CSP) investigations of an active pharmaceutical ingredient’s lattice energy landscape are a potent tool for assisting experimentalists in identifying and characterising novel polymorphic forms that are thermodynamically feasible, including ones that crystallise with twisted morphologies [2-4]. Oxcarbazepine (OXCBZ) is a pharmaceutical used for the treatment of epileptic seizures and three polymorphic forms have been reported, two of which (form I and form II) crystallise in the monoclinic space groups P21/c and P21 respectively [5]. OXCBZ form III was originally prepared by slow evaporation from methanol solutions containing polymer additives but structure determination was not possible because of the small size and poor quality of the crystals produced. Herein, we present robust protocols for the crystallisation of OXCBZ III from both solution and the vapour phase. Our efforts combined CSP studies of OXCBZ with physical vapour deposition and solution-based polymorph screening experiments. Needle-like and fibre-like crystals of form III exhibiting variable twisted habit were serendipitously obtained through vapour deposition of OXCBZ onto metallic substrates. By performing scanning electron and atomic force microscopy investigations we have managed to gain insight into the mechanism of formation and growth of the twisted OXCBZ III crystals over the course of the deposition process

Polymorph screening studies of oxcarbazepine : twisted habit in crystals of the elusive form III

Crystal structures exhibiting twisted morphology have been observed at the nanoscale, mesoscale, and macroscale and are challenging to characterise structurally because of their lack of long-range translational symmetry [1]. Crystal structure prediction (CSP) studies of an active pharmaceutical ingredient’s lattice energy landscape are often utilised for assisting experimentalists in identifying and characterising novel polymorphic forms that are thermodynamically feasible, including ones that crystallise with twisted morphologies [2-4]. Oxcarbazepine (OXCBZ) is a commercially available pharmaceutical used for the treatment of epilepsy and three polymorphic forms have been reported, two of which (form I and form II) are known to crystallise in the monoclinic space groups P21/c and P21 respectively [5]. Form III of OXCBZ was originally prepared by slow evaporation from methanol solutions that contained polymer additives but structure solution was not possible because of the small size and poor quality of the crystals. Herein, we present experimental protocols for the crystallization of OXCBZ III from both solution and the vapour phase. In our work, we combined CSP studies of OXCBZ with physical vapour deposition studies and solution-based polymorph screening experiments. Needle-like and fibre-like crystals of OXCBZ III exhibiting variable twisted habit emerged from vapour deposition of OXCBZ onto metallic substrates. Scanning electron and atomic force microscopy studies have been carried out to obtain an insight into the mechanism of formation and growth of the twisted OXCBZ III crystals over the course of the deposition process

Prediction of mefenamic acid crystal shape by random forest classification

Purpose: This study describes the development and application of machine-learning models to the prediction of the crystal shape of mefenamic acid recrystallized from organic solvents. Method: Mefenamic acid crystals were grown in 30 different solvents and categorized according to crystal shape as either polyhedral or needle. A total of 87 random forest classification models were trained on this data. Initially, 3 models were built to assess the efficacy of this method. These models were trained on datasets containing Molecular Operating Environment (MOE) descriptors for the solvents and crystal shapes labels obtained by visual inspection of microscope images. The subsequent 84 models tested prediction accuracy for individual solvents that were sequentially excluded from the model training sets. In total, three different sets of MOE descriptors (one set that contained all available 2D descriptors, a second set that focused on molecular structure and a third set that focused on physical properties) were investigated to determine which of these three sets of descriptors resulted in the highest overall prediction accuracy across the different solvents. Results: For the initial three models, the highest prediction accuracy of crystal shape observed was 93.5% as assessed by 4-fold cross-validation. When solvents were sequentially excluded from training data, 32 out of 84 models predicted the shape of mefenamic acid crystals for the excluded solvent with 100% accuracy and a further 21 models had prediction accuracies from 50-100%. Reducing the feature set to only solvent physical property descriptors and supersaturations resulted in higher overall prediction accuracies than the models using atom count, bond count, and pharmacophore descriptors and the models using all solvent molecular descriptors. For the 8 solvents on which the models performed poorly (<50% accuracy), further characterisation of crystals grown in these solvents resulted in the discovery of a new mefenamic acid solvate. However, all other crystals were the previously known form I. Conclusion: Random forest classification models using solvent physical property descriptors can reliably predict crystal morphologies for mefenamic acid crystals grown in 20 out of the 28 solvents included in this work. Poor prediction accuracies for the remaining 7 solvents may be an indication that the factors not adequately covered by the training data result in these solvents being outliers

Crystal Structure and Twisted Aggregates of Oxcarbazepine Form III

Polymorphism and crystal habit play vital roles in dictating the properties of crystalline materials. Here, the structure and properties of oxcarbazepine (OXCBZ) form III are reported along with the occurrence of twisted crystalline aggregates of this metastable polymorph. OXCBZ III can be produced by crystallization from the vapor phase and by recrystallization from solution. The crystallization process used to obtain OXCBZ III is found to affect the pitch, with the most prominent effect observed from the sublimation-grown OXCBZ III material where the pitch increases as the length of aggregates increases. Sublimation-grown OXCBZ III follows an unconventional mechanism of formation with condensed droplet formation and coalescence preceding nucleation and growth of aggregates. A crystal structure determination of OXCBZ III from powder X-ray diffraction methods, assisted by crystal structure prediction (CSP), reveals that OXCBZ III, similar to carbamazepine form II, contains void channels in its structure with the channels, aligned along the c crystallographic axis, oriented parallel to the twist axis of the aggregates. The likely role of structural misalignment at the lattice or nanoscale is explored by considering the role of molecular and closely related structural impurities informed by crystal structure prediction

Relating Neuronal to Behavioral Performance: Variability of Optomotor Responses in the Blowfly

Behavioral responses of an animal vary even when they are elicited by the same stimulus. This variability is due to stochastic processes within the nervous system and to the changing internal states of the animal. To what extent does the variability of neuronal responses account for the overall variability at the behavioral level? To address this question we evaluate the neuronal variability at the output stage of the blowfly's (Calliphora vicina) visual system by recording from motion-sensitive interneurons mediating head optomotor responses. By means of a simple modelling approach representing the sensory-motor transformation, we predict head movements on the basis of the recorded responses of motion-sensitive neurons and compare the variability of the predicted head movements with that of the observed ones. Large gain changes of optomotor head movements have previously been shown to go along with changes in the animals' activity state. Our modelling approach substantiates that these gain changes are imposed downstream of the motion-sensitive neurons of the visual system. Moreover, since predicted head movements are clearly more reliable than those actually observed, we conclude that substantial variability is introduced downstream of the visual system