Autonomous rendezvous targeting techniques for national launch system application

The rendezvous targeting techniques that can be utilized to achieve autonomous guidance for delivering a cargo to Space Station Freedom (SSF) using the National Launch System's (NLS) Heavy Lift Launch Vehicle (HLLV) and the on-orbit Cargo Transfer Vehicle (CTV) are described. This capability is made possible by advancements in autonomous navigation (Global Positioning System - GPS) on-board the CTV and SSF as well as the new generation flight computers. How the HLLV launch window can be decoupled from the CTV phasing window is described. The performance trades that have to be made to determine the length of the launch window and the phasing window between the CTV and SSF are identified and recommendations made that affect mission timelines

Enhancing Perception of Complex Sculptural Forms using Interactive Real-time Ray tracing

This paper looks at experiments into using real-time ray tracing to significantly enhance shape perception of complex three-dimensional digitally created structures. The author is a computational artist whose artistic practice explores the creation of intricate organic three-dimensional forms using simulation of morphogenesis. The generated forms are often extremely detailed, comprising tens of millions of cellular primitives. This often makes depth perception of the resulting structures difficult. His practice has explored various techniques to create presentable artefacts from the data, including high resolution prints, animated videos, stereoscopic installations, 3D printing and virtual reality. The author uses ray tracing techniques to turn the 3D data created from his morphogenetic simulations into visible artefacts. This is typically a time-consuming process, taking from seconds to minutes to create a single frame. The latest generation of graphics processing units offer dedicated hardware to accelerate ray tracing calculations. This potentially allows the generation of ray traced images, including self-shadowed complex structures and multiple levels of transparency, from new viewpoints at frame rates capable of real-time interaction. The author presents the results of his experiments using this technology with the aim of providing significantly enhanced perception of his generated three-dimensional structures by allowing user-initiated interaction to generate novel views, and utilizing depth cues such as stereopsis, depth from motion and defocus blurring. The intention is for these techniques to be usable to present new exhibitable works in a gallery context

A plan for spacecraft automated rendezvous

An automated rendezvous approach has been developed that utilizes advances in technology to reduce real-time/near real-time flight operations support personnel to an acceptable level that is near the minimum without jeopardizing the success of the mission. The on-board flight targeting uses a rule-based system to select the pursuit vehicle phasing orbits and uses precise navigation updates from the pursuit/target spacecraft made possible by the global positioning system receivers/processors on both spacecraft to adjust the phasing orbits and achieve rendezvous. The ascent-to-orbit targeting for the pursuit vehicle has been successfully decoupled from the on-orbit orbit transfer phasing targeting. Typical launch window data have been developed for the heavy lift launch vehicle and cargo transfer vehicle for a Space Station Freedom rendezvous mission

Developing ethical guidelines for positive psychology practice: An on-going, iterative, collaborative endeavour

As positive psychology has developed as a field, questions have arisen around how to ensure best practice, including with respect to ethics. This issue is particularly pertinent vis-à-vis its applied dimensions, such as positive psychology interventions by students and graduates of MAPP programmes. However, the field has hitherto lacked clear ethical guidelines to assist practitioners. Aiming to address this gap, the authors have devised a set of guidelines, in collaboration with key stakeholders across the positive psychology community, published in the International Journal of Wellbeing. The current article briefly summarises the importance, development, content, and future directions of these guidelines, thus providing a concise overview of this important project. It is hoped that this article, together with the guidelines themselves, will not only highlight the importance of ethical practice, but offer practical suggestions for guiding practitioners in the field

Why has it been so difficult to prove the efficacy of alpha-1-antitrypsin replacement therapy? Insights from the study of disease pathogenesis

Alpha-1-antitrypsin is the most abundant circulating protease inhibitor. It is mainly produced by the liver and secreted into the circulation where it acts to prevent excessive proteolytic damage in the lungs by the enzyme neutrophil elastase. The most common severe deficiency allele is the Z mutation, which causes the protein to self-associate into ordered polymers. These polymers accumulate within hepatocytes to cause liver damage. The resulting lack of circulating α1-antitrypsin predisposes the Z homozygote to proteolytic lung damage and emphysema. Other pathways may also contribute to the development of lung disease. In particular, polymers of Z α1-antitrypsin can form within the lung where they act as a pro-inflammatory stimulus that may exacerbate protease-mediated lung damage. Researchers recognized in the 1980s that plasma α1-antitrypsin levels could be restored by intravenous infusions of purified human protein. Alpha-1-antitrypsin replacement therapy was introduced in 1987 but subsequent clinical trials have produced conflicting results, and to date there remains no widely accepted clinical evidence of the efficacy of α1-antitrypsin replacement therapy. This review addresses our current understanding of disease pathogenesis in α1-antitrypsin deficiency and questions why this treatment in isolation may not be effective. In particular it discusses the possible role of α1-antitrypsin polymers in exacerbating intrapulmonary inflammation and attenuating the efficacy of α1-antitrypsin replacement therapy

Polymers and inflammation: disease mechanisms of the serpinopathies

Members of the serpin (serine proteinase inhibitor) superfamily play a central role in the control of inflammatory, coagulation, and fibrinolytic cascades. Point mutations that cause abnormal conformational transitions in these proteins can trigger disease. Recent work has defined three pathways by which these conformers cause tissue damage. Here, we describe how these three mechanisms can be integrated into a new model of the pathogenesis of emphysema caused by mutations in the serpin α1-antitrypsin

Genetic susceptibility.

Why only 20% of smokers develop clinically relevant chronic obstructive pulmonary disease (COPD) was a puzzle for many years. Now, epidemiologic studies point clearly toward a large heritable component. The combination of genome-wide association studies and candidate gene analysis is helping to identify those genetic variants responsible for an individual's susceptibility to developing COPD. In this review, the current data implicating specific loci and genes in the pathogenesis of COPD are examined