Space Transportation System solid rocket booster thrust vector control system

The Solid Rocket Booster, Thrust Vector Control (TVC) system was designed in accordance with the following requirements: self-contained power supply, failsafe operation, 20 flight uses after exposure to seawater landings, optimized cost, and component interchangeability. Trade studies were performed which led to the selection of a recirculating hydraulic system powered by Auxiliary Power Units (APU) which drive the hydraulic actuators and gimbal the solid rocket motor nozzle. Other approaches for the system design were studied in arriving at the recirculating hydraulic system powered by an APU. These systems must withstand the imposed environment and be usable for a minimum of 20 Space Transportation System flights with a minimum of refurbishment. The TVC system completed the required qualification and verification tests and is certified for the intended application. Substantiation data include analytical and test data

Static Friction between Elastic Solids due to Random Asperities

Several workers have established that the Larkin domains for two three dimensional nonmetallic elastic solids in contact with each other at a disordered interface are enormously large. This implies that there should be negligible static friction per unit area in the macroscopic solid limit. The present work argues that the fluctuations in the heights of the random asperities at the interface that occur in the Greenwood-Williamson model can account for static friction.Comment: Contains some improvements in the treatment of the subjec

Extracardiac 18F-florbetapir imaging in patients with systemic amyloidosis: more than hearts and minds

PURPOSE: 18F-Florbetapir has been reported to show cardiac uptake in patients with systemic light-chain amyloidosis (AL). This study systematically assessed uptake of 18F-florbetapir in patients with proven systemic amyloidosis at sites outside the heart. METHODS: Seventeen patients with proven cardiac amyloidosis underwent 18F-florbetapir PET/CT imaging, 15 with AL and 2 with transthyretin amyloidosis (ATTR). Three patients had repeat scans. All patients had protocolized assessment at the UK National Amyloidosis Centre including imaging with 123I-serum amyloid P component (SAP). 18F-Florbetapir images were assessed for areas of increased tracer accumulation and time-uptake curves in terms of standardized uptake values (SUVmean) were produced. RESULTS: All 17 patients showed 18F-florbetapir uptake at one or more extracardiac sites. Uptake was seen in the spleen in 6 patients (35%; 6 of 9, 67%, with splenic involvement on 123I-SAP scintigraphy), in the fat in 11 (65%), in the tongue in 8 (47%), in the parotids in 8 (47%), in the masticatory muscles in 7 (41%), in the lungs in 3 (18%), and in the kidney in 2 (12%) on the late half-body images. The 18F-florbetapir spleen retention index (SRI) was calculated. SRI >0.045 had 100% sensitivity/sensitivity (in relation to 123I-SAP splenic uptake, the current standard) in detecting splenic amyloid on dynamic imaging and a sensitivity of 66.7% and a specificity of 100% on the late half-body images. Intense lung uptake was seen in three patients, one of whom had lung interstitial infiltration suggestive of amyloid deposition on previous high-resolution CT. Repeat imaging showed a stable appearance in all three patients suggesting no early impact of treatment response. CONCLUSION: 18F-Florbetapir PET/CT is a promising tool for the detection of extracardiac sites of amyloid deposition. The combination of uptake in the heart and uptake in the spleen on 18F-florbetapir PET/CT, a hallmark of AL, suggests that this tracer holds promise as a screening tool for AL

Comparative assessment of onabotulinumtoxinA and mirabegron for overactive bladder: an indirect treatment comparison

CONTEXT: OnabotulinumtoxinA and mirabegron have recently gained marketing authorisation to treat symptoms of overactive bladder (OAB). OBJECTIVE: To evaluate the relative efficacy of mirabegron and onabotulinumtoxinA in patients with idiopathic OAB. DESIGN: Network meta-analysis. DATA SOURCES: A search of 9 electronic databases, review documents, guidelines and websites. METHODS: Randomised trials comparing any licensed dose of onabotulinumtoxinA or mirabegron with each other, anticholinergic drugs or placebo were eligible (19 randomised trials were identified). 1 reviewer extracted data from the studies and a second reviewer checked the data. Candidate trials were assessed for similarity and networks were developed for each outcome. Bayesian network meta-analysis was conducted using both fixed-effects and random-effects models. When there were differences in mean baseline values between mirabegron and onabotulinumtoxinA trials they were adjusted for using network meta-regression (NMR). RESULTS: No studies directly comparing onabotulinumtoxinA to mirabegron were identified. A network was created for each of the 7 outcomes, with 3-9 studies included in each individual network. The trials included in the networks were broadly similar. Patients in the onabotulinumtoxinA trials had more urinary incontinence and urgency episodes at baseline than patients in the mirabegron trials and these differences were adjusted for using NMR. Both onabotulinumtoxinA and mirabegron were more efficacious than placebo at reducing the frequency of urinary incontinence, urgency, urination and nocturia. OnabotulinumtoxinA was more efficacious than mirabegron (50 and 25 mg) in completely resolving daily episodes of urinary incontinence and urgency and in reducing the frequency of urinary incontinence, urgency and urination. NMR supported the results of the network meta-analysis. CONCLUSIONS: In the absence of head-to-head trials comparing onabotulinumtoxinA to mirabegron, this indirect comparison indicates that onabotulinumtoxinA may be superior to mirabegron in improving symptoms of urinary incontinence, urgency and urinary frequency in patients with idiopathic OAB

A well-separated pairs decomposition algorithm for k-d trees implemented on multi-core architectures

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Variations of k-d trees represent a fundamental data structure used in Computational Geometry with numerous applications in science. For example particle track tting in the software of the LHC experiments, and in simulations of N-body systems in the study of dynamics of interacting galaxies, particle beam physics, and molecular dynamics in biochemistry. The many-body tree methods devised by Barnes and Hutt in the 1980s and the Fast Multipole Method introduced in 1987 by Greengard and Rokhlin use variants of k-d trees to reduce the computation time upper bounds to O(n log n) and even O(n) from O(n2). We present an algorithm that uses the principle of well-separated pairs decomposition to always produce compressed trees in O(n log n) work. We present and evaluate parallel implementations for the algorithm that can take advantage of multi-core architectures.The Science and Technology Facilities Council, UK

Politics Between and Within Us: Authenticity and Theatricality in Modern Political Thought

This dissertation details the ways in which two distinct models of politics — the politics of authenticity and the politics of theatricality — have influenced political rhetoric and activity in America and beyond. The focus on authenticity in politics goes back to the ancients, yet it has taken on greater political significance in the modern era. Morally-charged language of “telling the truth”, or “being oneself” in politics has meant that public judgment and analysis has increasingly focused on the interiority of the speaker: one’s intentions, feelings and consistency, rather than on the persuasive case one is attempting to communicate. In the extreme, this has led to some nefarious actions and political regimes in the modern world (e.g. the Terror of the French Revolution and twentieth century totalitarianism) as well as less severe but still troubling results (the lack of a dynamic public sphere in which our everyday political discourse takes place). To combat the theory that led to these developments, I offer an analysis of theatrical politics which sees politics as something existing “outside and between us” rather than “within us.” At the same time, I acknowledge the ways in which authenticity in politics has led to emancipatory movements of oppressed persons and groups (e.g. abolitionism and civil rights, especially in America). The main representative of authentic politics I employ in this dissertation is Jean-Jacques Rousseau, and for theatricality, I detail the arguments of Hannah Arendt. I argue that we can find a proper balance between the two models in the politics of Henry David Thoreau. Ultimately, I explain the potential for a politics in which the best elements of each model could be practiced

Decoupling algorithms from schedules for easy optimization of image processing pipelines

Using existing programming tools, writing high-performance image processing code requires sacrificing readability, portability, and modularity. We argue that this is a consequence of conflating what computations define the algorithm, with decisions about storage and the order of computation. We refer to these latter two concerns as the schedule, including choices of tiling, fusion, recomputation vs. storage, vectorization, and parallelism. We propose a representation for feed-forward imaging pipelines that separates the algorithm from its schedule, enabling high-performance without sacrificing code clarity. This decoupling simplifies the algorithm specification: images and intermediate buffers become functions over an infinite integer domain, with no explicit storage or boundary conditions. Imaging pipelines are compositions of functions. Programmers separately specify scheduling strategies for the various functions composing the algorithm, which allows them to efficiently explore different optimizations without changing the algorithmic code. We demonstrate the power of this representation by expressing a range of recent image processing applications in an embedded domain specific language called Halide, and compiling them for ARM, x86, and GPUs. Our compiler targets SIMD units, multiple cores, and complex memory hierarchies. We demonstrate that it can handle algorithms such as a camera raw pipeline, the bilateral grid, fast local Laplacian filtering, and image segmentation. The algorithms expressed in our language are both shorter and faster than state-of-the-art implementations.National Science Foundation (U.S.) (Grant 0964004)National Science Foundation (U.S.) (Grant 0964218)National Science Foundation (U.S.) (Grant 0832997)United States. Dept. of Energy (Award DE-SC0005288)Cognex CorporationAdobe System

Size and power properties of some tests in the Birnbaum-Saunders regression model

The Birnbaum-Saunders distribution has been used quite effectively to model times to failure for materials subject to fatigue and for modeling lifetime data. In this paper we obtain asymptotic expansions, up to order $n^{-1/2}$ and under a sequence of Pitman alternatives, for the nonnull distribution functions of the likelihood ratio, Wald, score and gradient test statistics in the Birnbaum-Saunders regression model. The asymptotic distributions of all four statistics are obtained for testing a subset of regression parameters and for testing the shape parameter. Monte Carlo simulation is presented in order to compare the finite-sample performance of these tests. We also present an empirical application.Comment: Paper submitted for publication, with 13 pages and 1 figur