17 research outputs found
Complex Decision-Making Applications for the NASA Space Launch System
The Space Shuttle program is ending and elements of the Constellation Program are either being cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. Thus, multiple questions must be addressed: Which heavy lift vehicle will best allow the agency to achieve mission objectives in the most affordable and reliable manner? Which heavy lift vehicle will allow for a sufficiently flexible exploration campaign of the solar system? Which heavy lift vehicle configuration will allow for minimizing risk in design, test, build and operations? Which heavy lift vehicle configuration will be sustainable in changing political environments? Seeking to address these questions drove the development of an SLS decision-making framework. From Fall 2010 until Spring 2011, this framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper discusses the various methods of this process that allowed for competing concepts to be compared across a variety of launch vehicle metrics. The end result was the identification of SLS launch vehicle candidates that could successfully meet the threshold requirements in support of the SLS Mission Concept Review (MCR) milestone
Space Launch System Complex Decision-Making Process
The Space Shuttle program has ended and elements of the Constellation Program have either been cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. From Fall 2010 until Spring 2011, an SLS decision-making framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper focuses on the various steps and methods of this process (rather than specific data) that allowed for competing concepts to be compared across a variety of launch vehicle metrics in support of the successful completion of the SLS Mission Concept Review (MCR) milestone
Analysis of Shroud Options in Support of the Human Exploration of Mars
In support of the Mars Design Reference Architecture (DRA) 5.0, the NASA study team analyzed several shroud options for use on the Ares V launch vehicle.1,2 These shroud options included conventional "large encapsulation" shrouds with outer diameters ranging from 8.4 to 12.9 meters (m) and overall lengths of 22.0 to 54.3 meters, along with a "nosecone-only" shroud option used for Mars transfer vehicle component delivery. Also examined was a "multi-use" aerodynamic encapsulation shroud used for launch, Mars aerocapture, and entry, descent, and landing of the cargo and habitat landers. All conventional shroud options assessed for use on the Mars launch vehicles were the standard biconic design derived from the reference shroud utilized in the Constellation Program s lunar campaign. It is the purpose of this paper to discuss the technical details of each of these shroud options including material properties, structural mass, etc., while also discussing both the volume and mass of the various space transportation and surface system payload elements required to support a "minimum launch" Mars mission strategy, as well as the synergy, potential differences and upgrade paths that may be required between the Lunar and Mars mission shrouds
Robotic-assisted laparoscopic mesh sacrocolpopexy
The current ‘gold standard’ surgical repair for apical prolapse
is the abdominal mesh sacrocolpopexy. Use of a robotic-assisted laparoscopic
surgical approach has been demonstrated to be feasible as a minimally invasive
approach and is gaining popularity amongst pelvic floor reconstructive surgeons.
Although outcome data for robotic-assisted sacrocolpopexy (RASC) is only just
emerging, several small series have demonstrated anatomic and functional
outcomes, as well as complication rates, comparable to those reported for open
surgery. The primary advantages thus far for RASC over open surgery include
decreased blood loss and shorter hospital stay
Right ventricular morphology and systolic function in left ventricular noncompaction cardiomyopathy
The distinction between normal right ventricular (RV) trabeculations from abnormal has been difficult. We evaluated whether RV volume and function are related to left ventricular (LV) noncompaction (NC) cardiomyopathy and clinical events. Trabeculations or possible LVNC by cardiac magnetic resonance imaging was retrospectively observed among 105 consecutive cases. We measured LV end-systolic (ES) noncompacted-to-compacted ratio, RV ejection fraction (EF), RV apical trabecular thickness, and RV end-diastolic (ED) noncompacted-to-compacted ratio. A control group of 40 subjects was also reviewed to assess the exploratory measures
Comparative genomics reveals dynamic genome evolution in host specialist ectomycorrhizal fungi.
While there has been significant progress characterizing the 'symbiotic toolkit' of ectomycorrhizal (ECM) fungi, how host specificity may be encoded into ECM fungal genomes remains poorly understood. We conducted a comparative genomic analysis of ECM fungal host specialists and generalists, focusing on the specialist genus Suillus. Global analyses of genome dynamics across 46 species were assessed, along with targeted analyses of three classes of molecules previously identified as important determinants of host specificity: small secreted proteins (SSPs), secondary metabolites (SMs) and G-protein coupled receptors (GPCRs). Relative to other ECM fungi, including other host specialists, Suillus had highly dynamic genomes including numerous rapidly evolving gene families and many domain expansions and contractions. Targeted analyses supported a role for SMs but not SSPs or GPCRs in Suillus host specificity. Phylogenomic-based ancestral state reconstruction identified Larix as the ancestral host of Suillus, with multiple independent switches between white and red pine hosts. These results suggest that like other defining characteristics of the ECM lifestyle, host specificity is a dynamic process at the genome level. In the case of Suillus, both SMs and pathways involved in the deactivation of reactive oxygen species appear to be strongly associated with enhanced host specificity
Right Ventricular Morphology and Systolic Function in Left Ventricular Noncompaction Cardiomyopathy
Evolution of zygomycete secretomes and the origins of terrestrial fungal ecologies.
Fungi survive in diverse ecological niches by secreting proteins and other molecules into the environment to acquire food and interact with various biotic and abiotic stressors. Fungal secretome content is, therefore, believed to be tightly linked to fungal ecologies. We sampled 132 genomes from the early-diverging terrestrial fungal lineage zygomycetes (Mucoromycota and Zoopagomycota) and characterized their secretome composition. Our analyses revealed that phylogeny played an important role in shaping the secretome composition of zygomycete fungi with trophic mode contributing a smaller amount. Reconstruction of the evolution of secreted digestive enzymes revealed lineage-specific expansions, indicating that Mucoromycota and Zoopagomycota followed different trajectories early in their evolutionary history. We identified the presence of multiple pathogenicity-related proteins in the lineages known as saprotrophs, suggesting that either the ecologies of these fungi are incompletely known, and/or that these pathogenicity-related proteins have important functions associated with saprotrophic ecologies, both of which invite further investigation
The Relevance of Procedural Utility for Economics
This paper aims at showing the relevance of procedural utility for economics: people do not only care about outcomes, as usually assumed in economics, they also value the processes and conditions leading to outcomes. The psychological foundations of procedural utility are outlined and it is discussed how the concept differs from other related approaches in economics, like outcome utility, outcome fairness or intentions. Institutions at the level of society and fair procedures are shown to be sources of procedural utility, and novel empirical evidence on the role of procedural utility in important areas of the economy, polity and society is presented