Expressive re-performance

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 167-171).Many music enthusiasts abandon music studies because they are frustrated by the amount of time and effort it takes to learn to play interesting songs. There are two major components to performance: the technical requirement of correctly playing the notes, and the emotional content conveyed through expressivity. While technical details like pitch and note order are largely set, expression, which is accomplished through timing, dynamics, vibrato, and timbre, is more personal. This thesis develops expressive re-performance, which entails the simplification of technical requirements of music-making to allow a user to experience music beyond his technical level, with particular focus on expression. Expressive re-performance aims to capture the fantasy and sound of a favorite recording by using audio extraction to split the original target solo and giving expressive control over that solo to a user. The re-performance experience starts with an electronic mimic of a traditional instrument with which the user steps-through a recording. Data generated from the users actions is parsed to determine note changes and expressive intent. Pitch is innate to the recording, allowing the user to concentrate on expressive gesture. Two pre-processing systems, analysis to discover note starts and extraction, are necessary. Extraction of the solo is done through user provided mimicry of the target combined with Probabalistic Latent Component Analysis with Dirichlet Hyperparameters. Audio elongation to match the users performance is performed using time-stretch. Instrument interfaces used were Akais Electronic Wind Controller (EWI), Fender's Squier Stratocaster Guitar and Controller, and a Wii-mote. Tests of the system and concept were performed using the EWI and Wii-mote for re-performance of two songs. User response indicated that while the interaction was fun, it did not succeed at enabling significant expression. Users expressed difficulty learning to use the EWI during the short test window and had insufficient interest in the offered songs. Both problems should be possible to overcome with further test time and system development. Users expressed interest in the concept of a real instrument mimic and found the audio extractions to be sufficient. Follow-on work to address issues discovered during the testing phase is needed to further validate the concept and explore means of developing expressive re-performance as a learning tool.by Laurel S. Pardue.S.M

Violin Augmentation Techniques for Learning Assistance

PhDLearning violin is a challenging task requiring execution of pitch tasks with the left hand using a strong aural feedback loop for correctly adjusting pitch, concurrent with the right hand moving a bow precisely with correct pressure across strings. Real-time technological assistance can help a student gain feedback and understanding helpful for learning and maintaining motivation. This thesis presents real-time low-cost low-latency violin augmentations that can be used to assist learning the violin along with other real-time performance tasks. To capture bow performance, we demonstrate a new means of bow tracking by measuring bow hair de ection from the bow hair being pressed against the string. Using near- eld optical sensors placed along the bow we are able to estimate bow position and pressure through linear regression from training samples. For left hand pitch tracking, we introduce low cost means for tracking nger position and illustrate the combination of sensed results with audio processing to achieve high accuracy low-latency pitch tracking. We subsequently verify our new tracking methods' e ectiveness and usefulness demonstrating low-latency note onset detection and control of real-time performance visuals. To help tackle the challenge of intonation, we used our pitch estimation to develop low latency pitch correction. Using expert performers, we veri ed that fully correcting pitch is not only disconcerting but breaks a violinist's learned pitch feedback loop resulting in worse asplayed performance. However, partial pitch correction, though also linked to worse as-played performance, did not lead to a signi cantly negative experience con rming its potential for use to temporarily reduce barriers to success. Subsequently, in a study with beginners, we veri ed that when the pitch feedback loop is underdeveloped, automatic pitch correction did not signi cantly hinder performance, but o ered an enjoyable low-pitch error experience and that providing an automatic target guide pitch was helpful in correcting performed pitch error

College Attainment, Income Inequality, and Economic Security: A Simulation Exercise

We conduct an empirical simulation exercise that gauges the plausible impact of increased rates of college attainment on a variety of measures of income inequality and economic insecurity. Using two different methodological approaches—a distributional approach and a causal parameter approach—we find that increased rates of bachelor’s and associate degree attainment would meaningfully increase economic security for lower-income individuals, reduce poverty and near-poverty, and shrink gaps between the 90th and lower percentiles of the earnings distribution. However, increases in college attainment would not significantly reduce inequality at the very top of the distribution

Three flavors of extremal Betti tables

We discuss extremal Betti tables of resolutions in three different contexts. We begin over the graded polynomial ring, where extremal Betti tables correspond to pure resolutions. We then contrast this behavior with that of extremal Betti tables over regular local rings and over a bigraded ring.Comment: 20 page

Multiple inducers of the Drosophila heat shock locus 93D (hsr omega): inducer-specific patterns of the three transcripts

The Drosophila hsr omega locus produces one of the largest and most active heat shock puffs, yet it does not encode a heat shock protein. Instead, this locus produces a distinctive set of three transcripts, all from the same start site. The largest transcript, omega 1, is limited to the nucleus and appears to have a role there. A second nuclear transcript, omega 2, is produced by alternative termination and contains the sequence found in the 5' 20-25% of omega 1 (depending on the Drosophila species). The cytoplasmic transcript, omega 3, is produced by removal of a 700-bp intron from omega 2. All three hsr omega RNAs are produced constitutively and production is enhanced by heat shock. In addition to being a member of the set of heat shock puffs, the hsr omega puff is induced by agents that do not affect other heat shock loci, suggesting that hsr omega is more sensitive to environmental changes than other loci. We report here that agents that induce puffing of hsr omega loci in polytene nuclei also lead to an increase in hsr omega transcripts in diploid cells. We also show that the relative levels of omega 1 and omega 3 can be modulated independently by several agents. All drugs that inhibit translation, either initiation or elongation, stabilize the omega 3 transcript, which normally turns over within minutes in control cells. Drugs (such as benzamide and colchicine) that induce puffing of hsr omega, but not other heat shock loci, lead to large increases in omega 1. Although the constitutive level of omega 1 is relatively stable, the drug-induced excess is lost rapidly when the drug is withdrawn. The relative levels of hsr omega transcripts may reflect different states in cellular metabolism

HDAC Regulates Transcription at the Outset of Axolotl Tail Regeneration

Tissue regeneration is associated with complex changes in gene expression and post-translational modifications of proteins, including transcription factors and histones that comprise chromatin. We tested 172 compounds designed to target epigenetic mechanisms in an axolotl (Ambystoma mexicanum) embryo tail regeneration assay. A relatively large number of compounds (N = 55) inhibited tail regeneration, including 18 histone deacetylase inhibitors (HDACi). In particular, romidepsin, an FDA-approved anticancer drug, potently inhibited tail regeneration when embryos were treated continuously for 7 days. Additional experiments revealed that romidepsin acted within a very narrow, post-injury window. Romidepsin treatment for only 1-minute post amputation inhibited regeneration through the first 7 days, however after this time, regeneration commenced with variable outgrowth of tailfin tissue and abnormal patterning. Microarray analysis showed that romidepsin altered early, transcriptional responses at 3 and 6-hour post-amputation, especially targeting genes that are implicated in tumor cell death, as well as genes that function in the regulation of transcription, cell differentiation, cell proliferation, pattern specification, and tissue morphogenesis. Our results show that HDAC activity is required at the time of tail amputation to regulate the initial transcriptional response to injury and regeneration

A ‘higher order' of telomere regulation: telomere heterochromatin and telomeric RNAs

Protection of chromosome ends from DNA repair and degradation activities is mediated by specialized protein complexes bound to telomere repeats. Recently, it has become apparent that epigenetic regulation of the telomric chromatin template critically impacts on telomere function and telomere-length homeostasis from yeast to man. Across all species, telomeric repeats as well as the adjacent subtelomeric regions carry features of repressive chromatin. Disruption of this silent chromatin environment results in loss of telomere-length control and increased telomere recombination. In turn, progressive telomere loss reduces chromatin compaction at telomeric and subtelomeric domains. The recent discoveries of telomere chromatin regulation during early mammalian development, as well as during nuclear reprogramming, further highlights a central role of telomere chromatin changes in ontogenesis. In addition, telomeres were recently shown to generate long, non-coding RNAs that remain associated to telomeric chromatin and will provide new insights into the regulation of telomere length and telomere chromatin. In this review, we will discuss the epigenetic regulation of telomeres across species, with special emphasis on mammalian telomeres. We will also discuss the links between epigenetic alterations at mammalian telomeres and telomere-associated diseases

Comparison of dot chromosome sequences from D. melanogaster and D. virilis reveals an enrichment of DNA transposon sequences in heterochromatic domains

BACKGROUND: Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago. RESULTS: Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %). CONCLUSION: Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging

Distinct Differences in Chromatin Structure at Subtelomeric X and Y' Elements in Budding Yeast

In Saccharomyces cerevisiae, all ends of telomeric DNA contain telomeric repeats of (TG1–3), but the number and position of subtelomeric X and Y' repeat elements vary. Using chromatin immunoprecipitation and genome-wide analyses, we here demonstrate that the subtelomeric X and Y' elements have distinct structural and functional properties. Y' elements are transcriptionally active and highly enriched in nucleosomes, whereas X elements are repressed and devoid of nucleosomes. In contrast to X elements, the Y' elements also lack the classical hallmarks of heterochromatin, such as high Sir3 and Rap1 occupancy as well as low levels of histone H4 lysine 16 acetylation. Our analyses suggest that the presence of X and Y' elements govern chromatin structure and transcription activity at individual chromosome ends