Study of onboard expert systems to augment space shuttle and space station autonomy

The feasibility of onboard crew activity planning was examined. The use of expert systems technology to aid crewmembers in locating stowed equipment was also investigated. The crew activity planning problem, along with a summary of past and current research efforts, was discussed in detail. The requirements and specifications used to develop the crew activity planning system was also defined. The guidelines used to create, develop, and operate the MFIVE Crew Scheduler and Logistics Clerk were discussed. Also discussed is the mathematical algorithm, used by the MFIVE Scheduler, which was developed to aid in optimal crew activity planning

Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 1: Telepresence technology base development

The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program is presented, leading to an operational telepresence servicer

Space applications of Automation, Robotics And Machine Intelligence Systems (ARAMIS). Volume 3, phase 2: Executive summary

The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program leading to an operational telepresence servicer is presented

Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 2: Telepresence project applications

The field of telepresence is defined and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA' plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included

Development and Field Evaluation of an Aquifer Stratification Testing System

An aquifer stratification testing system was designed, constructed, and tested. The system was designed to characterize vertical profiles of both quantity and quality of water produced from actively pumping groundwater wells. During testing, all systems functioned properly and either met or exceeded anticipated performance requirements. The system was first tested in an irrigation well completed in the Edwards aquifer and owned by the Onion Creek Club located in Manchaca, Texas, just south of Austin. The purpose of the exercise was to assess test systems performance and to develop and refine testing procedures. Dye-tracer injection tests were performed at five depths from 325 to 405 ft, and a velocity/discharge profile was generated for that interval. The profile was consistent with the karst nature of the Edwards aquifer. Water sampling procedures were tested and evaluated, but no samples were analyzed. Further testing was performed in two public water supply wells completed in the Ogallala Formation of the High Plains aquifer and belonging to the City of Wolfforth, Texas, to investigate arsenic and fluoride concentration distributions, which both exceed maximum contaminant level (MCL) standards for arsenic (10 μg/L) and fluoride (4 mg/L) in produced water. The results indicated vertical trends in both arsenic and fluoride aquifer concentration profiles, although concentrations at all depths exceeded MCL standards for both arsenic and fluoride. Despite distinctly different water discharge profiles between wells, a consistent inverse depth relationship between arsenic and fluoride concentrations was identified in both wells. Aquifer arsenic concentrations generally decreased, and aquifer fluoride concentrations generally increased with increasing depth. Aquifer arsenic concentrations ranged from 11.4 to 14.1 μg/L in Well 8 and from 16.0 to 22.2 μg/L in Well 5. Aquifer fluoride concentrations ranged from 5.53 to 7.98 mg/L in Well 8 and from 4.28 to 5.87 mg/L in Well 5. Future system and procedural modifications should focus on improving and enhancing the flexibility and data acquisition capabilities of the system. Future field testing programs should be performed to develop a water quality stratification database to enhance general understanding of groundwater quality and flow processes and provide insight on potential contamination sources.Bureau of Economic Geolog

Guided genome halving: hardness, heuristics and the history of the Hemiascomycetes

Motivation: Some present day species have incurred a whole genome doubling event in their evolutionary history, and this is reflected today in patterns of duplicated segments scattered throughout their chromosomes. These duplications may be used as data to ‘halve’ the genome, i.e. to reconstruct the ancestral genome at the moment of doubling, but the solution is often highly nonunique. To resolve this problem, we take account of outgroups, external reference genomes, to guide and narrow down the search

Clinical and pathophysiologic spectrum of acquired distal renal tubular acidosis

Clinical and pathophysiologic spectrum of acquired distal renal tubular acidosis. Urinary acidification was studied in nine patients with hyper-chloremic metabolic acidosis. The aim of this study was to investigate the mechanism(s) of impaired distal acidification by the systematic administration of sodium sulfate and neutral phosphate. No impairment of proximal acidification was apparent because all patients had a fractional bicarbonate excretion below 5% at plasma bicarbonate concentrations above 22 mEq/liter. All patients except two were unable to lower urine pH below 5.5 despite systemic metabolic acidosis. The two patients who lowered urine pH normally were hyperkalemic and had selective aldosterone deficiency. Six patients failed to lower the urine pH below 5.5 with sodium sulfate (6.04 ± 0.16) and were unable to achieve a normal urine minus blood (U-B) Pco2 gradient with neutral phosphate (2.8 ± 3.5mm Hg). Control subjects, the two patients with selective aldosterone deficiency, and the remaining patient lowered the urine pH below 5.5 and increased the U-B Pco2 gradient above 25mm Hg in response to sodium sulfate and neutral phosphate infusion, respectively. The abnormal response to these agents exhibited by six patients strongly suggests that the mechanism of impaired distal acidification was that of secretory failure of the proton pump. The normal response of the remaining three patients indicates that the proton pump was able to secrete hydrogen ions normally under maximal stimulation. This pattern is totally predictable in patients with isolated selective aldosterone deficiency who are also capable of lowering the urine pH normally in the presence of systemic metabolic acidosis. The distinctive acidification pattern of the remaining patient who was also hyperkalemic can be explained on the basis of a voltage-dependent type of distal renal tubular acidosis. This type may be disclosed by the findings of impairment of both hydrogen ion and potassium secretion.Aspects clinique et physiopathologique de l'acidose tubulaire distale acquise. L'acidification urinaire a été étudiée chez neuf malades ayant une acidose métabolique hyperchlorémique. Le but de ce travail était d'étudier le mécanisme de l'altération de l'acidification distale par l'administration de sulfate de sodium et de phosphate neutre. Il n'est pas apparu d'altération de l'acidication proximale puisque tous les malades avaient une excrétion fractionnelle de bicarbonate inférieure à 5% à des concentrations de bicarbonate plasmatique supérieures à 22 mEq/litre. Tous les malades sauf deux étaient incapables d'abaisser leur pH urinaire au dessous de 5,5 malgré l'acidose métabolique. Les deux malades qui abaissaient le pH de l'urine à des valeurs normales étaient hyperkaliémiques et avaient un déficit sélectif d'aldostérone. Six malades n'ont pu abaisser leur pH urinaire en dessous de 5,5 avec le sulfate de sodium (6,04 ± 0,16) et ont été incapables de réaliser un gradient de Pco2 normal urine-sang sous phosphate neutre (2,8 ± 3,5mm Hg). Les sujets contrôles, les deux malades ayant un déficit d'aldostérone et le dernier malade ont abaissé le pH de l'urine au dessous de 5,5 et augmenté le gradient de Pco2 à plus de 25mm Hg en réponse aux administrations de sulfate de sodium et de phosphate neutre, respectivement. La résponse anormale des six malades suggère fortement que le mécanisme de l'altération de l'acidification distale est un défaut de fonctionnement de la pompe à protons. La réponse normale des trois derniers malades indique que la pompe était capable de sécréter des ions hydrogène dans des conditions de stimulation maximales. Cette modalité est prévisible chez les malades qui ont un déficit sélectif et isolé d'aldostérone et qui sont aussi capables d'abaisser le pH de leur urine en présence d'une acidose métabolique systémique. La modalité d'acidification particulière du dernier malade qui était en même temps hyperkaliémique peut être expliquée par un mécanisme dépendant de la différence de potentiel. Cette situation peut être reconnue par la constatation d'un désordre portant à la fois sur la sécrétion de ions hydrogène et celle de potassium

Transistors

Contains reports on eight research projects.Lincoln Laboratory under Contract AF19(122)-45

Why highly expressed proteins evolve slowly

Much recent work has explored molecular and population-genetic constraints on the rate of protein sequence evolution. The best predictor of evolutionary rate is expression level, for reasons which have remained unexplained. Here, we hypothesize that selection to reduce the burden of protein misfolding will favor protein sequences with increased robustness to translational missense errors. Pressure for translational robustness increases with expression level and constrains sequence evolution. Using several sequenced yeast genomes, global expression and protein abundance data, and sets of paralogs traceable to an ancient whole-genome duplication in yeast, we rule out several confounding effects and show that expression level explains roughly half the variation in Saccharomyces cerevisiae protein evolutionary rates. We examine causes for expression's dominant role and find that genome-wide tests favor the translational robustness explanation over existing hypotheses that invoke constraints on function or translational efficiency. Our results suggest that proteins evolve at rates largely unrelated to their functions, and can explain why highly expressed proteins evolve slowly across the tree of life.Comment: 40 pages, 3 figures, with supporting informatio