T HIS paper presents a s tudy designed to measure accurately the changes tha t occur in formation and absorption of cerebrospinal fluid within cerebral ventricles during development hydrocephalus. The results these experiments are considered relation evaluation hydrocephalic patient. A infant on ventrieular drainage will produce several hundred cc. cerebrospina] per day, but rate growth rapidly progressing hydrocephalus is only order 10 15 co. small fraction amount being formed. Clearly,...

This is a new book by Dr. Davson and not just edition of his old book, Physiology Ocular Cerebrospinal Fluids . It includes consideration the extracellular fluid brain problem blood-brain barriers as well physiology cerebrospinal fluid. brings together much experimental work that has been done in last 15 years. He demonstrates both (CSF) are secretions sense they products metabolic effort. points out this conclusion means controlled production central nervous system contrasted to simple...

T HIS paper presents an experimental test of the assumption that force formation cerebrospinal fluid causes eerebrospinal to circulate and ventricles enlarge when its pathways are blocked. These experiments show this assmnption is wrong a new description circulation given. I t has always been assumed cerebral ventricular enlargement hydroeephalus was caused by back pressure blocked fluid, but never put test. The clinical facts leave no doubt if some escapes from internal hydrocephalus will...

The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) VX-200i device was used to characterize an axial potential profile within expanding magnetic nozzle region of laboratory based device. ion acceleration mechanism is identified as ambipolar electric field produced by electron pressure gradient, resulting a local speed Mach 4 downstream nozzle. A 20 eV argon kinetic energy measured source, which had peak strength 0.17 T. source operated with 25 mg s−1...

The relationship of increased cerebral venous pressure to ventricular enlargement and hydrocephalus has never been satisfactorily worked out. interdependence intracranial recognized both in clinical problems experimental studies, but the possibility as a primary cause remained controversial issue. Dandy 2 stated that occlusion vein Galen would hydrocephalus. Others have tried this other types occlusions, with varying results. Russell, 4 her monograph on hydrocephalus, reviewed much work,...

On a clear day, there is downward electric field of 100 to 300 volts/meter at Earth's surface, although this not noticeable in daily life. That is, one does encounter 1 kV potential difference when getting into car on an upper floor parking garage, and electrocution the major hazard associated with jumping out trees. The reason why we don't notice fair-weather that virtually everything good conductor compared air. Objects such as tree trunks our bodies are excellent ionic conductors short...

The temporal and spatial scales of the onset two types substorm events are investigated. These substorms were cases where expansion had precursor localized auroral activation without significant negative bay enhancement, that is, “pseudobreakup”. High‐resolution energetic particle magnetic field data at synchronous orbit used for analysis together with simultaneously taken from ground‐based instrumentation. structure following pseudobreakup significantly resembled major aurora, except in its...

Measurements of cerebrospinal fluid production: a review the limitations and advantages current methodologies,

The cerebral oxygen consumption of monkeys ( Macaca mulatta) has been measured with the animals' rectal temperatures varying from 19° to 37° C. animals were allowed remain at experimental temperature for 1 hour before studies done. Cerebral was calculated using Kety-Schmidt nitrous oxide technique measuring blood flow. A linear relationship found between logarithm and reciprocal absolute (°K) body. This held over entire range studied a standard deviation about equal that method consumption.

Observations have been made of electric field oscillations near the local ion gyro frequency and an intense beam plasma ions at edge auroral arc. The observations are in good agreement with heating as saturation mechanism for electrostatic cyclotron waves.

Understanding the physics involved in plasma detachment from magnetic nozzles is well theorized, but lacking large scale experimental support. We have undertaken an experiment using 150-m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> variable specific impulse magnetoplasma rocket test facility and VX-200 thruster seeking evidence that occurs understanding of physical processes involved. It was found jet this does indeed detach applied...

The cerebrospinal fluid production has been studied in the dog under conditions of maximum obtainable flow rates from cisterna magna. Under these had constant composition and was assumed to represent intact state. Cerebral blood cerebral oxygen consumption were measured by method Kety Schmidt. only significant correlations found with when CSF rate terms brain weight vascular resistance choroid plexus weight. A combined regression equation calculated which satisfactorily accounted for...

The VAriable Specific Impulse Magnetoplasma Rocket (VASIMR®) is a high power electric spacecraft propulsion system, capable of Isp/thrust modulation at constant [F. R. Chang Díaz et al., Proceedings the 39th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 8–11 Jan. 2001]. VASIMR® uses helicon discharge to generate plasma. This plasma energized by an rf booster stage that left hand polarized slow mode waves launched from field side ion cyclotron resonance. In experiments reported in...

H IGH-POWER electric propulsion thrusters can reduce propellant mass for heavy-payload orbit-raising missions and cargo to the moon near-Earth asteroids, they trip time of robotic piloted planetary [1–4]. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) VX-200 engine is an system capable processing power densities on order 6 MW=m with a high specific impulse (4000 6000 s) inherent capability vary thrust at constant power. potential long lifetime due primarily radial magnetic...

A mechanism for ambipolar ion acceleration in a magnetic nozzle is proposed. The plasma adiabatic (i.e., does not exchange energy with its surroundings) the diverging section of so any lost by electrons must be transferred to ions via electric field. Fluid theory indicates that change potential proportional average electron energy. These predictions were compared measurements VX-200 experiment which has conditions conducive acceleration. planar Langmuir probe was used measure potential,...

Abstract Atmospheric electric field measurements from the Concordia station on Antarctic Plateau are compared with those Vostok (560 km away) for period of overlap (2009–11) and to Carnegie (1915–29) extended (2006–11) measurements. The data sorted according several sets criteria rejecting local variability examine a summer-noon influence improve estimates global signal. contribution solar wind is evaluated removed Simultaneous yield days when covariability at exceeds 90%, as well intervals...

Emissions that appear to have been electrostatic ion cyclotron (EIC) waves observed at low altitude in the diffuse aurora by a sounding rocket payload. The was launched from Poker Flat, Alaska, ∼2030 MLT. flight successively traversed ∼70 km of aurora, dark region, and quiet 40 kR auroral arc. In peaks were power spectrum electric field frequencies near hydrogen oxygen frequencies. Doppler shift polarization analyses performed using EIC wave parameters derived linear theory. Both indicated...