ABSTRACT
We report on artificial descending plasma layers created in the ionosphere F region by high-power high-frequency (HF) radio waves from High-frequency Active Auroral Research Program at frequencies f(0) near the fourth electron gyroharmonic 4f(ce). The data come from concurrent measurements of the secondary escaping radiation from the HF-pumped ionosphere, also known as stimulated electromagnetic emission, reflected probing signals at f(0), and plasma line radar echoes. The artificial layers appeared only for injections along the magnetic field and f(0)>4f(ce) at the nominal HF interaction altitude in the background ionosphere. Their average downward speed ~0.5 km/s holds until the terminal altitude where the local fourth gyroharmonic matches f(0). The total descent increases with the nominal offset f(0)-4f(ce).
ABSTRACT
Langmuir cavitons have been artificially produced in Earth's ionosphere, but evidence of naturally occurring cavitation has been elusive. By measuring and modeling the spectra of electrostatic plasma modes, we show that natural cavitating, or strong, Langmuir turbulence does occur in the ionosphere, via a process in which a beam of auroral electrons drives Langmuir waves, which in turn produce cascading Langmuir and ion-acoustic excitations and cavitating Langmuir turbulence. The data presented here are the first direct evidence of cavitating Langmuir turbulence occurring naturally in any space or astrophysical plasma.
ABSTRACT
We studied the orthopedic surgery service at our institution to determine whether the mere availability of autologous blood (AB) affected transfusion practice. As a group, patients who had AB available received an average of 1.11 fewer red cell units per hospitalization than did patients with only homologous blood (HB) available. At every transfusion episode, those patients having AB available received fewer red cell units than did patients without AB available. Predeposit of autologous red cells was effective in protecting 77.6% of patients from HB exposure. The availability of autologous red cells resulted in an overall more conservative approach to transfusion.
