Nasal Guide for the Stomach Tube.

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Onboard Atmospheric Modeling and Prediction for Autonomous Aerobraking Missions

Aerobraking has proven to be an effective means of increasing the science payload for planetary orbiting missions and/or for enabling the use of less expensive launch vehicles. Though aerobraking has numerous benefits, large operations cost have been required to maintain the aerobraking time line without violating aerodynamic heating or other constraints. Two operations functions have been performed on an orbit by orbit basis to estimate atmospheric properties relevant to aerobraking. The Navigation team typically solves for an atmospheric density scale factor using DSN tracking data and the atmospheric modeling team uses telemetric accelerometer data to recover atmospheric density profiles. After some effort, decisions are made about the need for orbit trim maneuvers to adjust periapsis altitude to stay within the aerobraking corridor. Autonomous aerobraking would reduce the need for many ground based tasks. To be successful, atmospheric modeling must be performed on the vehicle in near real time. This paper discusses the issues associated with estimating the planetary atmosphere onboard and evaluates a number of the options for Mars, Venus and Titan aerobraking missions

Stress et prévention de la récurrence de la maladie coronarienne

Les facteurs habituellement associés à l'augmentation du risque de maladie coronarienne (MC), tels le régime alimentaire, l'hyperlipidémie, la cigarette, l'inactivité physique et l'hérédité sont maitenant bien connus. Toutefois, Keys et al ainsi que d'autres auteurs ont montré que ces facteurs jouent un rôle dans seulement la moitié ou moins des cas de maladie coronarienne et qu'il y a assez d'exceptions pour indiquer la présence d'autres facteurs étiologiques. L'apparition de cette malade est aussi reliée à des caractéristiques psychologiques et sociales aussi bien qu'à des événements stressants de la vie. Enfin, d'autre études ont suggéré que les survivants d'épisodes coronariens ont une vie plus stressante, parfois aggravée par l'interaction d'autres facteurs intervenant avant, durant, et après l'infarctus ; par exemple, la durée de la maladie, la période de convalescence, l'attitude des amis, les conditions familiales et de travail. La nature de la réaction du patient et de sa famille au stress et aux conflits apparaît alors essentielle pour déterminer s'il y aura ou non rechute de la maladie ou nécessité d'une réhospitalisation. De plus, en s'appuyant sur les précédentes données, il devrait être possible de prédire, par la surveillance du niveau de stress, à quel moment une personne atteinte de cette maladie aura un nouvel épisode coronarien. Mieux encore, il devrait être possible d'aider les patients à résoudre les problèmes qui engendrent ce stress et dans certains cas, prévenir ainsi les rechutes.A good deal of recent research suggests that a period of mounting life stress is a precursor of many physical illnesses, including episodes of coronary heart disease (CHD). It should be possible then, by monitoring levels of stress to predict when a high risk individual is likely to suffer a further illness episode, and in some cases to prevent the episode by alleviating stress producing problems.Based on this concept, we have telephone-monitored (at monthly intervals) 37 CHD patients discharged from the coronary unit of the Montreal General Hospital. Stress was measured using a 20-item, self-report scale (Goldberg), and charted for each patient over a seven month period. When a patient's stress rose above a critical level he received a home visit by the project nurse, who investigated his problems and attempted to alleviate them. Interventions varied from simple reassurance to referral for psychiatric treatment or legal aid.Monitoring stress in this way revealed a picture remarkably like the theoretical model. None of the 15 consistently low-scoring patients required rehospitalization. Eleven patients had low scores at the time of discharge, but their scores rose above the critical level in subsequent months. Nine of them responded in a gratifying way- to the home visit and subsequent intervention by the nurse, and none required rehospitalization. The one patient of this type who did require hospitalization had not received a home visit because no nurse was available at the time. Four of the nine patients with consistently high scores required eight rehospitalization s for CHD episodes. These patients seemed to be chronically stressed, and often required continuous support from the nurse.Our study suggests that life stress may be more important than the traditional physical risk factors (obesity, smoking, hypertension, family history of CHD, lack of exercise) in the etiology of recurrent CHD when patients receive adequate medical care.Some of our findings suggest that the nurse's interventions do reduce rehospitalizations, but a large scale controlled study is called for.We conclude that this technique is worth further evaluation, both as a research method and as a practical device for the prevention of rehospitalization of CHD patients and of other types of episodic illnesses

A subjective refraction procedure for intellectually disadvantaged patients

A subjective refraction procedure for intellectually disadvantaged patients plus instructions to parent/teachers

Autonomous Aerobraking: A Design, Development, and Feasibility Study

Aerobraking has been used four times to decrease the apoapsis of a spacecraft in a captured orbit around a planetary body with a significant atmosphere utilizing atmospheric drag to decelerate the spacecraft. While aerobraking requires minimum fuel, the long time required for aerobraking requires both a large operations staff, and large Deep Space Network resources. A study to automate aerobraking has been sponsored by the NASA Engineering and Safety Center to determine initial feasibility of equipping a spacecraft with the onboard capability for autonomous aerobraking, thus saving millions of dollars incurred by a large aerobraking operations workforce and continuous DSN coverage. This paper describes the need for autonomous aerobraking, the development of the Autonomous Aerobraking Development Software that includes an ephemeris estimator, an atmospheric density estimator, and maneuver calculation, and the plan forward for continuation of this study

Autonomous Aerobraking Using Thermal Response Surface Analysis

Aerobraking is a proven method of significantly increasing the science payload that can be placed into low Mars orbits when compared to an all propulsive capture. However, the aerobraking phase is long and has mission cost and risk implications. The main cost benefit is that aerobraking permits the use of a smaller and cheaper launch vehicle, but additional operational costs are incurred during the long aerobraking phase. Risk is increased due to the repeated thermal loading of spacecraft components and the multiple attitude and propulsive maneuvers required for successful aerobraking. Both the cost and risk burdens can be significantly reduced by automating the aerobraking operations phase. All of the previous Mars orbiter missions that have utilized aerobraking have increasingly relied on onboard calculations during aerobraking. Even though the temperature of spacecraft components has been the limiting factor, operational methods have relied on using a surrogate variable for mission control. This paper describes several methods, based directly on spacecraft component maximum temperature, for autonomously predicting the subsequent aerobraking orbits and prescribing apoapsis propulsive maneuvers to maintain the spacecraft within specified temperature limits. Specifically, this paper describes the use of thermal response surface analysis in predicting the temperature of the spacecraft components and the corresponding uncertainty in this temperature prediction

An Atmospheric Variability Model for Venus Aerobraking Missions

Aerobraking has proven to be an enabling technology for planetary missions to Mars and has been proposed to enable low cost missions to Venus. Aerobraking saves a significant amount of propulsion fuel mass by exploiting atmospheric drag to reduce the eccentricity of the initial orbit. The solar arrays have been used as the primary drag surface and only minor modifications have been made in the vehicle design to accommodate the relatively modest aerothermal loads. However, if atmospheric density is highly variable from orbit to orbit, the mission must either accept higher aerothermal risk, a slower pace for aerobraking, or a tighter corridor likely with increased propulsive cost. Hence, knowledge of atmospheric variability is of great interest for the design of aerobraking missions. The first planetary aerobraking was at Venus during the Magellan mission. After the primary Magellan science mission was completed, aerobraking was used to provide a more circular orbit to enhance gravity field recovery. Magellan aerobraking took place between local solar times of 1100 and 1800 hrs, and it was found that the Venusian atmospheric density during the aerobraking phase had less than 10% 1 sigma orbit to orbit variability. On the other hand, at some latitudes and seasons, Martian variability can be as high as 40% 1 sigmaFrom both the MGN and PVO mission it was known that the atmosphere, above aerobraking altitudes, showed greater variability at night, but this variability was never quantified in a systematic manner. This paper proposes a model for atmospheric variability that can be used for aerobraking mission design until more complete data sets become available

Conditioning and Habituation of White-Tailed Deer to Two Common Deterrents

It was hypothesized white-tailed deer (Odocoileus virginianus) could be readily conditioned to 2 commonly used deterrents, Deer-Away® Big Game Repellent (BGR) and blood meal (BM). Plots were randomly assigned BGR, BM and control. Free-ranging deer were initially conditioned to forage for corn at each 49m 2 bare earth plots delivered at 0500 hr and 1600 hr by programmable siing-type feeders. Hoof prints were counted within a 3.7m 2 sample area of each plot to quantify activity. Following preconditioning, data were collected during 5, 5-day periods. Application of BGR and BM to their respective bare earth plots occurred during periods 2, 4 and 5. Initial exposure decreased the number of hoof-prints for BGR (P = 0.011) and BM (P = 0.033) compared to the control. Subsequent exposure to BGR during periods 4 and 5 did not differ from the control (P \u3e 0.227). Prints counted following exposure to BM were similar to the control in period 4 (P = 0.267), but lower (P = 0.045) in period 5. Within each treatment group , prints counted were lower during period 2 compared to periods 1, 3, 4 and 5 for both BGR (P =0.001) and BM (P = 0.018). No differences (P \u3e 0.05) were found among periods 1,3,4 and 5 within each treatment. Results support the hypothesis that white-tailed deer can readily be conditioned to these two commonly used deterrents

Autonomous three dimensional Newtonian systems which admit Lie and Noether point symmetries

We determine the autonomous three dimensional Newtonian systems which admit Lie point symmetries and the three dimensional autonomous Newtonian Hamiltonian systems, which admit Noether point symmetries. We apply the results in order to determine the two dimensional Hamiltonian dynamical systems which move in a space of constant non-vanishing curvature and are integrable via Noether point symmetries. The derivation of the results is geometric and can be extended naturally to higher dimensions.Comment: Accepted for publication in Journal of Physics A: Math. and Theor.,13 page