Receiver-Based Auralization of Broadband Aircraft Flyover Noise Using the NASA Auralization Framework

The NASA Auralization Framework (NAF) consists of a set of dynamic link libraries (DLLs) to facilitate auralization of aircraft noise. Advanced capabilities for synthesis, propagation, and external interfaces are provided by the NAF Advanced Plugin Libraries (APL); a separate set of DLLs that are made accessible through the NAFs plugin architecture. In the typical time domain use case, the sound is first synthesized at the source location based on a source noise definition, and is then propagated in the time domain to a receiver on or near the ground. Alternatively, it may be desirable to synthesize the sound at the receiver, after it has been propagated in the frequency domain, e.g., when the source definition is inaccessible or when alternative propagation methods are needed. Receiver-based auralization requires three new developments in the NAF APL: a component plugin to interpolate the propagated noise spectra as a function of time for input to sound synthesis, and a path finder and path traversal plugin to calculate the effects of the differential propagation path length between the direct and ground reflected rays. This paper describes those developments and demonstrates their use in the auralization of broadband flyover noise

On The Determination of Shadow Boundaries and Relevant Eigenrays For Sound Propagation In Stratified Moving Media

The eiconal and ray equations for a stratified moving medium are analyzed to determine which rays connect a source located at an altitude z = z(sub s) to an observer on the ground plane. The characteristics of all available rays are ascertained. Further, the rays which determine the shadow boundary are found. Thus, the shadow boundary may be easily calculated and any observers for which an eigenray does not exist eliminated from further consideration. Therefore, the analysis may be applied to save computer time in two ways. First, rays that do not reach the ground may be eliminated before they are traced, and observers for which no eigenray exists may be eliminated from consideration

Propagation Effects of Wind and Temperature on Acoustic Ground Contour Levels

Propagation characteristics for varying wind and temperature atmospheric conditions are identified using physically-limiting propagation angles to define shadow boundary regions. These angles are graphically illustrated for various wind and temperature cases using a newly developed ray-tracing propagation code

Validation of Ray Tracing Code Refraction Effects

NASA's current predictive capabilities using the ray tracing program (RTP) are validated using helicopter noise data taken at Eglin Air Force Base in 2007. By including refractive propagation effects due to wind and temperature, the ray tracing code is able to explain large variations in the data observed during the flight test

Identification and Phenotypic Characterization of Hsp90 Phosphorylation Sites That Modulate Virulence Traits in the Major Human Fungal Pathogen Candida albicans

The highly conserved, ubiquitous molecular chaperone Hsp90 is a key regulator of cellular proteostasis and environmental stress responses. In human pathogenic fungi, which kill more than 1.6 million patients each year worldwide, Hsp90 governs cellular morphogenesis, drug resistance, and virulence. Yet, our understanding of the regulatory mechanisms governing fungal Hsp90 function remains sparse. Post-translational modifications are powerful components of nature’s toolbox to regulate protein abundance and function. Phosphorylation in particular is critical in many cellular signaling pathways and errant phosphorylation can have dire consequences for the cell. In the case of Hsp90, phosphorylation affects its stability and governs its interactions with co-chaperones and clients. Thereby modulating the cell’s ability to cope with environmental stress. Candida albicans, one of the leading human fungal pathogens, causes ~750,000 life-threatening invasive infections world-wide with unacceptably high mortality rates. Yet, it remains unknown if and how Hsp90 phosphorylation affects C. albicans virulence traits. Here, we show that phosphorylation of Hsp90 is critical for expression of virulence traits. We combined proteomics, molecular evolution analyses and structural modelling with molecular biology to characterize the role of Hsp90 phosphorylation in this non-model pathogen. We demonstrated that phosphorylation negatively affects key virulence traits, such as the thermal stress response, morphogenesis, and drug susceptibility. Our results provide the first record of a specific Hsp90 phosphorylation site acting as modulator of fungal virulence. Post-translational modifications of Hsp90 could prove valuable in future exploitations as antifungal drug targets

Extracellular dsRNA induces a type I interferon response mediated via class A scavenger receptors in a novel Chinook salmon derived spleen cell line

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.dci.2018.08.010 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/Despite increased global interest in Chinook salmon aquaculture, little is known of their viral immune defenses. This study describes the establishment and characterization of a continuous cell line derived from Chinook salmon spleen, CHSS, and its use in innate immune studies. Optimal growth was seen at 14–18 °C when grown in Leibovitz's L-15 media with 20% fetal bovine serum. DNA analyses confirmed that CHSS was Chinook salmon and genetically different from the only other available Chinook salmon cell line, CHSE-214. Unlike CHSE-214, CHSS could bind extracellular dsRNA, resulting in the rapid and robust expression of antiviral genes. Receptor/ligand blocking assays confirmed that class A scavenger receptors (SR-A) facilitated dsRNA binding and subsequent gene expression. Although both cell lines expressed three SR-A genes: SCARA3, SCARA4, and SCARA5, only CHSS appeared to have functional cell-surface SR-As for dsRNA. Collectively, CHSS is an excellent cell model to study dsRNA-mediated innate immunity in Chinook salmon.Natural Sciences and Engineering Research Council of CanadaCanada Research Counci

NASA Hybrid Wing Aircraft Aeroacoustic Test Documentation Report

This report summarizes results of the Hybrid Wing Body (HWB) N2A-EXTE model aeroacoustic test. The N2A-EXTE model was tested in the NASA Langley 14- by 22-Foot Subsonic Tunnel (14x22 Tunnel) from September 12, 2012 until January 28, 2013 and was designated as test T598. This document contains the following main sections: Section 1 - Introduction, Section 2 - Main Personnel, Section 3 - Test Equipment, Section 4 - Data Acquisition Systems, Section 5 - Instrumentation and Calibration, Section 6 - Test Matrix, Section 7 - Data Processing, and Section 8 - Summary. Due to the amount of material to be documented, this HWB test documentation report does not cover analysis of acquired data, which is to be presented separately by the principal investigators. Also, no attempt was made to include preliminary risk reduction tests (such as Broadband Engine Noise Simulator and Compact Jet Engine Simulator characterization tests, shielding measurement technique studies, and speaker calibration method studies), which were performed in support of this HWB test. Separate reports containing these preliminary tests are referenced where applicable

Hybrid Wing Body Aircraft Acoustic Test Preparations and Facility Upgrades

NASA is investigating the potential of acoustic shielding as a means to reduce the noise footprint at airport communities. A subsonic transport aircraft and Langley's 14- by 22-foot Subsonic Wind Tunnel were chosen to test the proposed "low noise" technology. The present experiment studies the basic components of propulsion-airframe shielding in a representative flow regime. To this end, a 5.8-percent scale hybrid wing body model was built with dual state-of-the-art engine noise simulators. The results will provide benchmark shielding data and key hybrid wing body aircraft noise data. The test matrix for the experiment contains both aerodynamic and acoustic test configurations, broadband turbomachinery and hot jet engine noise simulators, and various airframe configurations which include landing gear, cruise and drooped wing leading edges, trailing edge elevons and vertical tail options. To aid in this study, two major facility upgrades have occurred. First, a propane delivery system has been installed to provide the acoustic characteristics with realistic temperature conditions for a hot gas engine; and second, a traversing microphone array and side towers have been added to gain full spectral and directivity noise characteristics

Beyond handover: supporting awareness for continuous coverage

Abstract Hospitals are required to operate as a continuous system because patient care cannot be temporarily suspended and handover is seen as a key method for enabling this. This paper reports a study of handover in a medical admissions unit. We draw on the notion of awareness as conceptualised within the Computer Supported Cooperative Work literature to explore the role played by a variety of cognitive artifacts in supporting continuous coverage. While such awareness is typically characterised as being ‘effortless’, our study reveals that maintaining awareness in a context such as the medical admissions unit is effortful due to invisible work. We suggest that the notion of awareness is beneficial for exploring the practices of continuous coverage because it moves attention away from the moment of handover, instead encouraging consideration of the variety of practices through which clinicians display their work to, and monitor the work of, colleagues on different shifts. We argue that efforts to support continuous coverage should focus on improving awareness by increasing the visibility of information

Mutualism and Adaptive Divergence: Co-Invasion of a Heterogeneous Grassland by an Exotic Legume-Rhizobium Symbiosis

Species interactions play a critical role in biological invasions. For example, exotic plant and microbe mutualists can facilitate each other's spread as they co-invade novel ranges. Environmental context may influence the effect of mutualisms on invasions in heterogeneous environments, however these effects are poorly understood. We examined the mutualism between the legume, Medicago polymorpha, and the rhizobium, Ensifer medicae, which have both invaded California grasslands. Many of these invaded grasslands are composed of a patchwork of harsh serpentine and relatively benign non-serpentine soils. We grew legume genotypes collected from serpentine or non-serpentine soil in both types of soil in combination with rhizobium genotypes from serpentine or non-serpentine soils and in the absence of rhizobia. Legumes invested more strongly in the mutualism in the home soil type and trends in fitness suggested that this ecotypic divergence was adaptive. Serpentine legumes had greater allocation to symbiotic root nodules in serpentine soil than did non-serpentine legumes and non-serpentine legumes had greater allocation to nodules in non-serpentine soil than did serpentine legumes. Therefore, this invasive legume has undergone the rapid evolution of divergence for soil-specific investment in the mutualism. Contrary to theoretical expectations, the mutualism was less beneficial for legumes grown on the stressful serpentine soil than on the non-serpentine soil, possibly due to the inhibitory effects of serpentine on the benefits derived from the interaction. The soil-specific ability to allocate to a robust microbial mutualism may be a critical, and previously overlooked, adaptation for plants adapting to heterogeneous environments during invasion