A dense disk of dust around the born-again Sakurai's object

In 1996, Sakurai's object (V4334 Sgr) suddenly brightened in the centre of a faint Planetary Nebula (PN). This very rare event was interpreted as the reignition of a hot white dwarf that caused a rapid evolution back to the cool giant phase. From 1998 on, a copious amount of dust has formed continuously, screening out the star which has remained embedded in this expanding high optical depth envelope. The new observations, reported here, are used to study the morphology of the circumstellar dust in order to investigate the hypothesis that Sakurai's Object is surrounded by a thick spherical envelope of dust. We have obtained unprecedented, high-angular resolution spectro-interferometric observations, taken with the mid-IR interferometer MIDI/VLTI, which resolve the dust envelope of Sakurai's object. We report the discovery of a unexpectedly compact (30 x 40 milliarcsec, 105 x 140 AU assuming a distance of 3.5 kpc), highly inclined, dust disk. We used Monte Carlo radiative-transfer simulations of a stratified disk to constrain its geometric and physical parameters, although such a model is only a rough approximation of the rapidly evolving dust structure. Even though the fits are not fully satisfactory, some useful and robust constraints can be inferred. The disk inclination is estimated to be 75+/-3 degree with a large scale height of 47+/-7 AU. The dust mass of the disk is estimated to be 6 10^{-5} solar mass. The major axis of the disk (132+/-3 degree) is aligned with an asymmetry seen in the old PN that was re-investigated as part of this study. This implies that the mechanism responsible for shaping the dust envelope surrounding Sakurai's object was already at work when the old PN formed.Comment: A&A Letter, accepte

Boston University Symphony Orchestra, Thursday, March 1, 2001

This is the concert program of the Boston University Symphony Orchestra performance on Thursday, March 1, 2001 at 8:00 p.m., at the Tsai Performance Center, 685 Commonwealth Avenue, Boston, Massachusetts. Works performed were A Night on Bald Mountain by Modest Mussorgsky, Oration by Frank Bridge, and La Mer by Claude Debussy. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

The sound motion controller: a distributed system for interactive music performance

We developed an interactive system for music performance, able to control sound parameters in a responsive way with respect to the user’s movements. This system is conceived as a mobile application, provided with beat tracking and an expressive parameter modulation, interacting with motion sensors and effector units, which are connected to a music output, such as synthesizers or sound effects. We describe the various types of usage of our system and our achievements, aimed to increase the expression of music performance and provide an aid to music interaction. The results obtained outline a first level of integration and foresee future cognitive and technological research related to it

Categorized bibliography for a conceptual model of salt marsh management on Merritt Island, Florida

Enclosed is a bibliography of 556 published articles, technical reports, theses, dissertations, and books that form the basis for a conceptual model of salt marsh management on Merritt Island, Florida (Section 1). A copy of each item is available on file at the Florida Cooperative Fish and Wildlife Research Unit, Gainesville. Some relevant proprietary items and unpublished drafts have not been included pending permission of the authors. We will continue to add pertinent references to our bibliography and files. Currently, some topics are represented by very few items. As our synthesis develops, we will be able to indicate a subset of papers most pertinent to an understanding of the ecology and management of Merritt Island salt marshes. (98 page document

A Vision-based Real-time Conductor Gesture Tracking System

[[abstract]]In recent years, interaction between humans and computers is becoming more important. “Virtual Orchestra” is an Human Computer Interface (HCI) software which attempts to authentically reproduce a live orchestra using synthesized and sampled instruments sounds. Compared with the traditional HCIs, using vision-based gesture can provide a touch-free interface which is less bounding than mechanical instruments. In this research, we design a vision-based system that can track the hand motions of a conductor from webcam and extract musical beats from motions. The algorithm used is based on a robust nonparametric technique for climbing density gradients to find the mode of probability distributions. For each frame, the mean shift algorithm converges to the mode of the distribution. Then, the CAMSHIFT algorithm is used to track the moving objects in a video scene. After acquiring the target center point continuously, we can form the trajectory of moving target (such as baton, conductor’s hand…etc). By computing an approximation of k-curvature for the trajectory, and the angle between these two motion vectors, we can compute the point of the change of direction. In this thesis, a system was developed for interpreting a conductor’s gestures and translating theses gestures into musical beats that can be explained as the major part of the music. This system does not require the use of active sensing, special baton, or other constraints on the physical motion of the conductor.

Designing and Composing for Interdependent Collaborative Performance with Physics-Based Virtual Instruments

Interdependent collaboration is a system of live musical performance in which performers can directly manipulate each other’s musical outcomes. While most collaborative musical systems implement electronic communication channels between players that allow for parameter mappings, remote transmissions of actions and intentions, or exchanges of musical fragments, they interrupt the energy continuum between gesture and sound, breaking our cognitive representation of gesture to sound dynamics. Physics-based virtual instruments allow for acoustically and physically plausible behaviors that are related to (and can be extended beyond) our experience of the physical world. They inherently maintain and respect a representation of the gesture to sound energy continuum. This research explores the design and implementation of custom physics-based virtual instruments for realtime interdependent collaborative performance. It leverages the inherently physically plausible behaviors of physics-based models to create dynamic, nuanced, and expressive interconnections between performers. Design considerations, criteria, and frameworks are distilled from the literature in order to develop three new physics-based virtual instruments and associated compositions intended for dissemination and live performance by the electronic music and instrumental music communities. Conceptual, technical, and artistic details and challenges are described, and reflections and evaluations by the composer-designer and performers are documented

Musical Haptic Wearables for Synchronisation of Visually-impaired Performers: a Co-design Approach

The emergence of new technologies is providing opportunities to develop novel solutions that facilitate the integration of visually-impaired people in different activities of our daily life, including collective music making. This paper presents a study conducted with visually-impaired music performers, which involved a participatory approach to the design of accessible technologies for musical communication in group playing. We report on three workshops that were conducted together with members of an established ensemble of solely visually-impaired musicians. The first workshop focused on the identification of the participants’ needs during the activity of playing in groups and how technology could satisfy such needs. The second and third workshops investigated, respectively, the activities of choir singing and instrument playing in ensemble, focusing on the key issue of synchronisation that was identified in the first workshop. The workshops involved prototypes of musical haptic wearables, which were co-designed and evaluated by the participants. Overall, results indicate that wireless tactile communication represents a promising avenue to cater effectively to the needs of visually-impaired performers

Diffeomorphism invariance in spherically symmetric loop quantum gravity

We study the issue of the recovery of diffeomorphism invariance in the recently introduced loop quantum gravity treatment of the exterior Schwarzschild space-time. Although the loop quantization agrees with the quantization in terms of metric variables in identifying the physical Hilbert space, we show that diffeomorphism invariance in space-time is recovered with certain limitations due to the use of holonomic variables in the loop treatment of the model. This resembles behaviors that are expected in the full theory.Comment: 5 pages, no figures, invited paper for a special issue of Advanced Science Letter

Fishes of the Mountain Province Section of the Ouachita River

A survey of the fishes of the mountain province section of the Ouachita River from the headwaters to Remmel Dam using field collections, literature records, and museum collections showed the ichthyofauna to be made up of 80 species representing 16 families. Fourteen species not previously reported from the mountain province section of the river were collected in this survey. These species include Ichthyomyzon gagei, Nocomis asper, Notropis ortenburgeri, N. rubellus, Pimephales promelas, Moxostoma carinatum, Noturus taylori, Fundulus notatus, Lepomis humilis, Etheostoma histrio, E. proeliare, Percina maculata, P. nasuta, and P. uranidea. The Nocomis specimens were the first collected from the Ouachita River system and the discovery of Noturus taylori represents a major range extension