A Bayesian coincidence test for noise rejection in a gravitational-wave burst search

In searches for gravitational-wave bursts, a standard technique used to reject noise is to discard burst event candidates that are not seen in coincidence in multiple detectors. A coincidence test in which Bayesian inference is used to measure how noise-like a tuple of events appears is presented here. This technique is shown to yield higher detection efficiencies for a given false alarm rate than do techniques based on per-parameter thresholds when applied to a toy model covering a broad class of event candidate populations. Also presented is the real-world example of a use of the technique for noise rejection in a time–frequency burst search conducted on simulated gravitational-wave detector data. Besides achieving a higher detection efficiency, the technique is significantly less challenging to implement well than is a per-parameter threshold method

Prediction of Acoustical Response of Three-dimensional Cavities Using an Indirect Boundary Element Method

A technique which characterizes the acoustics of generalized cavities with the minimum model possible is developed. All boundary element methods have two advantages over finite element methods: (1) the models are smaller; and (2) the assumed variable behavior, inherent in the method to allow discretization, is harmonic rather than polynomial. Further, IBEM often requires one rather than two numerical boundary integrals as required by DBEM. Thus, a quadratic, isoparametric IBEM program was developed. The source distribution in this solution is continuous and quadratically variable rather than continuous and constant. The program was also formulated to include the additional capability of interior point sources and impedance boundary conditions. To test the quadratic, isoparametric IBEM program, several simple cavity enclosure problems where studied. Results are shown

Kipp C. Brewer, Trumpet

Intrada / Otto Ketting; Recit et Choral / Georges Delerue; Trumpet Concerto in E-flat / Vincenzo Bellini; Concerto for Two Trumpets in C major, RV 537 / Antonio Vivaldi; Trumpet Concerto / Robert Planel; Napoli: Canzone Napolitana con Variazoni / Herman Bellsted

Dancing with dirt and wires; reconciling the embodied and the digital in site responsive collaborative practice

Acknowledging the practitioner-researcher model and collaboration inherent to twenty-first-century contemporary performance practices, this co- authored chapter is offered as an extension of an ongoing collaboration between two dance artists and a photographer working in outdoor performance under the project enter & inhabit. The writing process and resulting chapter moves between a reflection on process, a document of practice and a theorisation around live and digital composition, thus inviting a reconsideration of the relationship between the real and the virtual

Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures

Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean - presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure. Parameters for our model are constrained by observations of modern Earth and reconstructions of biomass burial and oxidative weathering in deep time. A 1-D climate model was used to model potential effects on atmospheric climate. In a second set of tests, we perturbed our box model to investigate which parameters have the greatest impact on the evolution of atmospheric pN2 and consider possible implications for nitrogen cycling on other planets. Our results suggest that (a) a high rate of biomass burial would have been needed in the Archean to draw down atmospheric pN2 to less than half modern levels, (b) the resulting effect on temperature could probably have been compensated by increasing solar luminosity and a mild increase in pCO2, and (c) atmospheric oxygenation could have initiated a stepwise pN2 rebound through oxidative weathering. In general, life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets. Our results further support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere.Comment: 33 pages, 11 figures, 2 tables (includes appendix), published in Astrobiolog

everything is at once: Reflections on embodied photography and collaborative process

In discussion with his co-collaborators, dance artists Natalie Garrett Brown and Amy Voris, this interview explores the photographic process of Christian Kipp, landscape and dance photographer, as he reflects on his experience of working on the Enter & Inhabit project. The questions asked by Garrett Brown and Voris were generated through movement and reflective writing in response to the photographic collection exhibited as part of the 2011 Dance and Somatic Practices Conference, Coventry, UK. In particular, the article explores the interrelationship between the somatic-informed movement practices and performance score creation of Garrett Brown and Voris and the sensorial play of Kipp’s photography. Co-authored by Garrett Brown, Kipp and Voris, this collection of questions and responses seeks to continue rather than merely document the Enter & Inhabit collaborative process

Time-Resolved Studies of a Rolled-Up Semiconductor Microtube Laser

We report on lasing in rolled-up microtube resonators. Time-resolved studies on these semiconductor lasers containing GaAs quantum wells as optical gain material reveal particularly fast turn-on-times and short pulse emissions above the threshold. We observe a strong red-shift of the laser mode during the pulse emission which is compared to the time evolution of the charge-carrier density calculated by rate equations

KINEMATIC AND KINETIC PATTERNS IN OLYMPIC WEIGHTLIFTING

The purpose of this study was to identify lower extremity kinematic and kinetic patterns during weightlifting movements and to compare them across different external loads. Subjects completed multiple sets of the clean exercise at various percentage loads. Principal component analysis (PCA) was used to extract kinematic and kinetics patterns of the hip, knee, and ankle joint across the loads. These patterns were then compared across joint and percentage load. Results indicate that lower extremity kinematics and kinetics can be characterized through combinations of PCA-derived patterns. Patterns differed predominantly between joints, but not across percentage loads. The results point to joint-specific lower extremity function during Olympic weightlifting and quantified important technical aspects

A study of leeside flow field heat transfer on Shuttle Orbiter configuration

A coupled inviscid and viscous theoretical solution of the flow about the entire configuration is the desirable and comprehensive approach to defining thermal environments about the space shuttle orbiter. Simplified methods for predicting entry heating on leeside surfaces of the orbiter are considered. Wind tunnel heat transfer and oil flow data at Mach 6 and 10 and Reynolds numbers ranging from 500,000 to 73 million were used to develop correlations for the wing upper surface and the top surface of the fuselage. These correlations were extrapolated to flight Reynolds number and compared with heating data obtained during the shuttle STS-2 reentry. Efforts directed toward the wing leeside surface resulted in an approach which generally agreed with the flight data. Heating predictions for the upper fuselage were less successful due to the extreme complexity of local flow interactions and the associated heating environment