Real-time remote scientific model validation

This paper describes flight results from the use of a CLIPS-based validation facility to compare analyzed data from a space life sciences (SLS) experiment to an investigator's preflight model. The comparison, performed in real-time, either confirms or refutes the model and its predictions. This result then becomes the basis for continuing or modifying the investigator's experiment protocol. Typically, neither the astronaut crew in Spacelab nor the ground-based investigator team are able to react to their experiment data in real time. This facility, part of a larger science advisor system called Principal Investigator in a Box, was flown on the space shuttle in October, 1993. The software system aided the conduct of a human vestibular physiology experiment and was able to outperform humans in the tasks of data integrity assurance, data analysis, and scientific model validation. Of twelve preflight hypotheses associated with investigator's model, seven were confirmed and five were rejected or compromised

Model-based scientific discovery--a study in space bioengineering

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1992.Includes bibliographical references (leaves 130-138).by Nicolas Groleau.Ph.D

Space science experimentation automation and support

This paper outlines recent work done at the NASA Ames Artificial Intelligence Research Laboratory on automation and support of science experiments on the US Space Shuttle in low earth orbit. Three approaches to increasing the science return of these experiments using emerging automation technologies are described: remote control (telescience), science advisors for astronaut operators, and fully autonomous experiments. The capabilities and limitations of these approaches are reviewed

Principal investigator in a box: Version 1.2 documentation

Principal Investigator (PI) in a box is a computer system designed to help optimize the scientific results of experiments that are performed in space. The system will assist the astronaut experimenters in the collection and analysis of experimental data, recognition and pursuit of 'interesting' results, optimal use of the time allocated to the experiment, and troubleshooting of the experiment apparatus. This document discusses the problems that motivate development of 'PI-in-a-box', and presents a high- level system overview and a detailed description of each of the modules that comprise the current version of the system

PI in the sky: The astronaut science advisor on SLS-2

The Astronaut Science Advisor (ASA, also known as Principal-Investigator-in-a-Box) is an advanced engineering effort to apply expert systems technology to experiment monitoring and control. Its goal is to increase the scientific value of information returned from experiments on manned space missions. The first in-space test of the system will be in conjunction with Professor Larry Young's (MIT) vestibulo-ocular 'Rotating Dome' experiment on the Spacelab Life Sciences 2 mission (STS-58) in the Fall of 1993. In a cost-saving effort, off-the-shelf equipment was employed wherever possible. Several modifications were necessary in order to make the system flight-worthy. The software consists of three interlocking modules. A real-time data acquisition system digitizes and stores all experiment data and then characterizes the signals in symbolic form; a rule-based expert system uses the symbolic signal characteristics to make decisions concerning the experiment; and a highly graphic user interface requiring a minimum of user intervention presents information to the astronaut operator. Much has been learned about the design of software and user interfaces for interactive computing in space. In addition, we gained a great deal of knowledge about building relatively inexpensive hardware and software for use in space. New technologies are being assessed to make the system a much more powerful ally in future scientific research in space and on the ground

Etude prospective multicentrique française sur les positions en neurochirurgie de la fosse postérieure

Objectif : La position assise dans la neurochirurgie de la fosse postérieure est actuellement discutée : elle favorise les conditions opératoires mais expose au risque d'embolie gazeuse. Cette étude comparait l'incidence de l'embolie gazeuse et ses conséquences sur la morbi-mortalité dans la position assise versus les autres positions. Patients et méthodes : étude prospective multicentrique sur 1 an. 10 centres ont répondu favorablement et ont inclus 321 patients. Le critère principal était l'embolie gazeuse et ses conséquences sur la morbi-mortalité. Les critères secondaires étaient les durées opératoires, le saignement peropératoire, les complications péri et postopératoires, et les durées de réanimation, ventilation, hospitalisation. Résultats : 31 patients ont eu une embolie gazeuse, tous en position assise et sans augmentation de la morbi-mortalité. Les durées opératoires étaient significativement plus longues chez les patients en position assise, les pertes sanguines équivalentes aux patients en position dorsale, latérale et genu-pectorale, les complications péri et post-opératoires plus nombreuses et les durées de réanimation et d'hospitalisation étaient significativement plus longue. Le PAC était un facteur d'hémorragie accrue pour les patients en position assise. Conclusion : Dans cette étude, les embolies ne sont survenues que chez les patients en position assise mais n'ont pas eu de conséquences sur la morbi-mortalité. Toutefois, l'analyse des critères secondaires mettait en évidence une surmorbidité. Il semblerait donc que la position assise ne devrait être réservée qu'aux patients ne pouvant être opérés dans d'autres positions.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Hypertension artérielle induite par noradrénaline versus haut débit cardiaque induit par dobutamine dans la prise en charge de l'hémorragie méningée suite à une rupture anévrysmale

Le vasospasme est la complication la plus redoutée des hémorragies méningées. La triple-H thérapie représente la principale prévention ainsi que le principal traitement du vasospasme. La composante hypertensive nécessite souvent de la noradrénaline. Cet agent vasoconstricteur vient s ajouter à la décharge cathécolaminergique qui survient à la phase initiale de l hémorragie méningée, et est parfois accuser d être en partie responsable de la survenue du vasospasme. La dobutamine, par ses propriétés vasodilatatrices, est intéressante dans la prise en charge des hémorragies méningées en augmentant le débit cardiaque. Nous avons comparé l utilisation de la dobutamine à l utilisation de la noradrénaline dans la prise en charge en réanimation des hémorragies méningées. Notre étude démontrait que la dobutamine diminuait la durée de ventilation et de séjour en réanimation par rapport à l utilisation de la noradrénaline. Le recours à la noradrénaline était nécessaire dans le groupe dobutamine, avec, cependant, une durée d utilisation réduite. Nous avons discuté ces résultats en les comparant à ceux de la littérature.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Estimation of the water quality of a large urbanized river as defined by the European WFD: what is the optimal sampling frequency?

International audienceAssessment of the quality of freshwater bodies is essential to determine the impact of human activities on water resources. The water quality status is estimated by comparing indicators with standard thresholds. Indicators are usually statistical criteria that are calculated on discrete measurements of water quality variables. If the time step of the measured time series is not sufficient to fully capture the variable’s variability, the deduced indicator may not reflect the system’s functioning. The goal of the present work is to assess, through a hydro-biogeochemical modeling approach, the optimal sampling frequency for an accurate estimation of 6 water quality indicators defined by the European Water Framework Directive (WFD) in a large human-impacted river, which receives large urban effluents (the Seine River across the Paris urban area). The optimal frequency depends on the sampling location and on the monitored variable. For fast varying compounds that originate from urban effluents, such as PO3−4, NH+4 and NO−2, a sampling time step of one week or less is necessary. To be able to reflect the highly transient character of bloom events, chl a concentrations also require a short monitoring time step. On the contrary, for variables that exert high seasonal variability, as NO−3 and O 2, monthly sampling can be sufficient for an accurate estimation of WFD indicators in locations far enough from major effluents. Integrative water quality variables, such as O 2, can be highly sensitive to hydrological conditions. It would therefore be relevant to assess the quality of water bodies at a seasonal scale rather than at annual or pluri-annual scales. This study points out the possibility to develop smarter monitoring systems by coupling both time adaptative automated monitoring networks and modeling tools used as spatio-temporal interpolators

Modélisation du fonctionnement hydro-écologique de la Seine: Impact des vases sur la qualité de l'eau

International audienc

Quantifying phytoplankton communities using spectral fluorescence: the effects of species composition and physiological state

International audienceIn situ fluorometers are the optimal means of providing high-frequency estimates of phytoplankton communities. However, they may be subjected to measurement biases originating from variations in the physiological states of cells, the use of spectral fluorescence signatures (SFS) defined on the basis of inappropriate phytoplankton groups and the lack of linear independence between selected sets of SFS. We assessed correction procedures for measurement biases in mono and mixed cultures of five freshwater phytoplankton species. We investigated the impacts of total Chla levels, the lack of linear independence between SFS and varying physiological states on the accuracy of the Chla estimates that were provided by the FluoroProbe (bbe Moldaenke GmbH, Germany). The use of species-specific SFS allowed for the correction of quantification and classification biases. In some cases, the procedure led to a lack of linear independence between SFS, which significantly reduced estimation accuracies. A convenient method to evaluate linear independence between SFS is provided. Differences in the physiological states of phytoplankton cultures following light pre-acclimation and/or N-starvation appeared to be species specific. Light pre-acclimation led to an underestimation of biomass (up to -28.5%) through fluorescence quenching. The responses of the phytoplankton cultures to N-starvation varied depending on the species (from -40.3 to +336% biases in Chla quantification). Overall, the application of appropriate corrective measures increased data accuracy. However, optimal data reliability can only be achieved by estimating phytoplankton community composition and associated environmental conditions