545 research outputs found

    Calculations of heavy ion charge state distributions for nonequilibrium conditions

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    Numerical calculations of the charge state distributions of test ions in a hot plasma under nonequilibrium conditions are presented. The mean ionic charges of heavy ions for finite residence times in an instantaneously heated plasma and for a non-Maxwellian electron distribution function are derived. The results are compared with measurements of the charge states of solar energetic particles, and it is found that neither of the two simple cases considered can explain the observations

    Observed distribution functions of H, He, C, O, and Fe in corotating energetic particle streams: Implications for interplanetary acceleration and propagation

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    Distribution functions for H, He, C, O, and Fe derived from our IMP 8 measurements of approximately 0.15 to approximately 8 MeV/nucleon particles in three corotating streams observed near earth are shown to have a simple exponential dependence on the particle speed. The e-folding speed, v sub o, is typically 0.01c, is found to be the same for the distribution functions of all elements examined, and varies little from one corotating event to the next. The relative abundances of energetic particles in these events resemble most closely the solar coronal composition and, thus, presumably that of the solar wind. These results may imply that the acceleration of these particles, which occurs in corotating interaction regions at several AU from the sun, is by a statistical process

    The mean ionic charge of silicon in 3HE-rich solar flares

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    Mean ionic charge of iron in 3He-rich solar flares and the average mean charge of Silicon for 23 #He-rich periods during the time interval from September 1978 to October 1979 were determined. It is indicated that the value of the mean charge state of Silicon is higher than the normal flare average by approximately 3 units and in perticular it is higher then the value predicted by resonant heating models for 3He-rich solar flares

    The energy spectra of solar flare electrons

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    A survey of 50 electron energy spectra from .1 to 100 MeV originating from solar flares was made by the combination of data from two spectrometers onboard the International Sun Earth Explorer-3 spacecraft. The observed spectral shapes of flare events can be divided into two classes through the criteria of fit to an acceleration model. This standard two step acceleration model, which fits the spectral shape of the first class of flares, involves an impulsive step that accelerates particles up to 100 keV and a second step that further accelerates these particles up to 100 MeV by a single shock. This fit fails for the second class of flares that can be characterized as having excessively hard spectra above 1 MeV relative to the predictions of the model. Correlations with soft X-ray and meter radio observations imply that the acceleration of the high energy particles in the second class of flares is dominated by the impulsive phase of the flares

    Iron charge states observed in the solar wind

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    Solar wind measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. Solar wind Fe charge state measurements from three time periods of high speed solar wind occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow solar wind indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream

    Temporal variations of the anomalous oxygen component, 1977 - 1984

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    A survey is of the long term temporal variations of 6.6 to 12 MeV/nucleon anomalous oxygen at 1 AU covering the period 1977 to 1984. This time interval included the recent solar maximum, with the recovery at neutron monitor energies beginning in 1982. During this time interval, 6.6 to 12 MeV/nucleon 0 fluxes decreased by at least a factor of 50, and indeed remained below the instrumental detection threshold after 1979. By late 1984, neutron monitors had recovered to roughly 1979 levels from the 1982 solar maximum, and anomalous O still remained below the detection threshold

    Parkinson's disease: cognition, pulmonary function and muscle strength

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    Parkinson's disease is a slowly progressive disease: the cause is still unknown. The symptoms can range from tremor, rigidity, bradykinesia, postural instability and autonomic dysfunction to cognitive disturbances. The pathophysiological mechanism for most of these symptoms is the degeneration of the nigrostriatal tract, leading to a shortage of dopamine in the striatum. Levodopa given orally, can be an effective drug for most of these symptoms, but not all symptoms respond equally. In addition, the progression of the disease continues in spite of levodopa treatment. Longterm levodopa treatment can lead to considerable side-effects. In the early phases of the disease amantadine and anti-cholinergics are to be preferred above levodopa. However, anticholinergics do have a reputation of side-effects with regard to cognitive function, since acetylcholine is an important neurotransmitter for systems involved in memory functions

    ArchE : Entwicklung einer datenbankunterstützten Architektur-Entwurfsumgebung; ein Anforderungsbericht

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    Eine Datenbankunterstützung des integrierten architektonischen Entwurfes stellt mannigfaltige Anforderungen, die von heutigen Datenbanksystemen nicht erfüllt werden können. Dieser Bericht hat zum Ziel, den allgemeinen architektonischen Planungsprozeß und speziell eine neuartige Entwurfsmethodik, die auf einem mehrdimensionalen Entwurfsraum, dem sogenannten A4--Raum basiert, zu beschreiben und hieraus die Anforderungen an die Funktionalität und die grundlegenden Konzepte einer Datenbankunterstützung für den Gebäudeentwurfsbereich abzuleiten
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