The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only ...three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have detected on opposite sides of the planet near 90 degrees E and 90 degrees W, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.
A comparison is presented of the 130-m images taken in the Venus thermosphere by the Pioneer Venus Orbiter Ultraviolet Spectrometer (PVOUVS) to predictions by a model which incorporates current ...understanding of the global structure of the thermosphere, the mechanisms which excite the 130-nm transition in O, and the radiative transport of the 130-nm triplet in the thermosphere. The features identified in the data/model comparison appear as a local time asymmetry in B(130) and O at altitudes poleward of 30 deg. Oxygen densities at the evening terminator are typically a factor of 2 higher than those at the morning terminator. This asymmetry in O has never before been observed or predicted in the global thermospheric models. (AIAA)
Mars Reconnaissance Orbiter (MRO) was launched 12 August 2005, achieved Mars Orbital Insertion (MOI) 10 March 2006, and successfully completed aerobraking 30 August 2006. This aerobraking allowed a ...savings of 400kg of fuel. On each of more than 400 orbits accelerometer measurements were obtained of vertical and spatial structure on inbound and outbound trajectories resulting in in situ measurements of density, scale height, temperature, and pressure of over 800 vertical structures above 100km. The location of MRO periapsis precessed from near the South Pole 6pm Local Solar Time (LST) to near the equator at 3am LST. Comparisons were made between the MRO accelerometer experiment measurements and similar accelerometer experiment measurements aboard Mars Global Surveyor (MGS) and Mars Odyssey (MO). The MRO results show large solar minimum to maximum changes and large solar distance effects (perihelion to aphelion). Winter polar warming discovered by the accelerometer measurements is much weaker near the South Winter Pole (aphelion) than near the North Winter Pole (perihelion), largely because of lower solar input. High amplitude (+/-20%) Kelvin waves were detected. Strong latitudinal and seasonal variations are detected. Day/night variations of a factor of 2 in density are observed at low latitudes. Excellent agreement in densities was discovered between MRO climatology (2006) and previous Mars Express (2004) climatology from SPICAM stellar occupations. A wealth of information up to an altitude of 200km has been established.
In a 14-month period mitral leaflet prolapse was diagnosed in 85 patients by echocardiography or cineangiography. Chest pain alone was the presenting complaint in 30 patients and linked with ...palpitation, dyspnoea, or syncope in 9. Eleven presented with major neurological disturbances (9 had transient ischaemic attacks), 10 with palpitation, 4 with undue and persistent fatigue, 2 with dyspnoea, and 2 with dizziness. Seventeen were referred not because of symptoms but because of clicks and murmurs. Overall, chest pain affected 61 patients and unless associated with coronary artery disease was not anginal. Palpitation was admitted by 42 patients; dizziness, lightheadedness, or paraesthesiae by 15, and syncope by 12. Systolic auscultatory abnormalities were noted in 69: 25 had single clicks, 3 had multiple clicks, 19 had both click(s) and murmur, and 22 had a murmur alone. Electrocardiography revealed ST segments flat for greater than 0-10 s in 21, prolonged QTc in 18, and T wave flattening or inversion in inferior limb and lateral chest leads in 14. The exercise stress test was abnormal in 13 of 27 patients. Mitral valve echograms showed definite mitral leaflet prolapse in 61, 'possible' prolapse in 14, and were normal in 8 patients with angiographic proof of mitral leaflet prolapse. Cardiac catheterization with left ventriculography showed prolapse of posterior mitral leaflet in 36, of both leaflets in 2, and left ventricular wall motion abnormalities in 16 cases. Selective coronary arteriography in 31 cases showed major vessel narrowing of larger than or equal to 80 per cent lumen diameter in 4, all with angina. This consecutive series indicates that the physical event of mitral leaflet prolapse is more common than hitherto appreciated, is priminently associated with non-anginal chest pain, palpitation, and neurological disturbances, and in 90 per cent of cases could be shown echocardiographically.
Neutral Atmospheres Mueller-Wodarg, I. C. F.; Strobel, D. F.; Moses, J. I. ...
Comparative Aeronomy
Book Chapter
This paper summarizes the understanding of aeronomy of neutral atmospheres in the solar system, discussing most planets as well as Saturn’s moon Titan and comets. The thermal structure and energy ...balance is compared, highlighting the principal reasons for discrepancies amongst the atmospheres, a combination of atmospheric composition, heliocentric distance and other external energy sources not common to all. The composition of atmospheres is discussed in terms of vertical structure, chemistry and evolution. The final section compares dynamics in the upper atmospheres of most planets and highlights the importance of vertical dynamical coupling as well as magnetospheric forcing in auroral regions, where present. It is shown that a first order understanding of neutral atmospheres has emerged over the past decades, thanks to the combined effects of spacecraft and Earth-based observations as well as advances in theoretical modeling capabilities. Key gaps in our understanding are highlighted which ultimately call for a more comprehensive programme of observation and laboratory measurements.
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