23,161 research outputs found
Direct observations in the dusk hours of the characteristics of the storm-time ring current particles during the beginning of magnetic storms
The characteristic features of the initial enhancement of the storm-time ring current particles in the evening hours are consistent with flow patterns resulting from a combination of inward convection, gradient drift, and corotation which carries plasma sheet protons into low L-values near midnight and the higher energy proton component into the plasmasphere and through the evening hours. Data from four magnetic storms during the early life of Explorer 45, when the local time of apogee was in the afternoon and evening hours, show that protons with lower magnetic moments penetrate deeper into the magnetosphere until a low limit, determined by the corotation and gradient drift forces, is reached. Such particle motions produce the stable energy dependent inner boundary of the ring current protons inside the plasmapause in the dusk sector and also provide the mechanism for energy injection into the ring current region. From the analyses of the pitch angle distributions it is evident that charge exchange and wave particle interactions are not the dominant causes of this inner boundary
Ring current proton decay by charge exchange
Explorer 45 measurements during the recovery phase of a moderate magnetic storm have confirmed that the charge exchange decay mechanism can account for the decay of the storm-time proton ring current. Data from the moderate magnetic storm of 24 February 1972 was selected for study since a symmetrical ring current had developed and effects due to asymmetric ring current losses could be eliminated. It was found that after the initial rapid decay of the proton flux, the equatorially mirroring protons in the energy range 5 to 30 keV decayed throughout the L-value range of 3.5 to 5.0 at the charge exchange decay rate calculated by Liemohn. After several days of decay, the proton fluxes reached a lower limit where an apparent equilibrium was maintained, between weak particle source mechanisms and the loss mechanisms, until fresh protons were injected into the ring current region during substorms. While other proton loss mechanisms may also be operating, the results indicate that charge exchange can entirely account for the storm-time proton ring current decay, and that this mechanism must be considered in all studies involving the loss of proton ring current particles
Inference of the ring current ion composition by means of charge exchange decay
The analysis of the measured ion fluxes during the several day storm recovery period and the assumption that beside hydrogen other ions were present and that the decays were exponential in nature, it was possible to establish three separate lifetimes for the ions. These fitted decay lifetimes are in excellent agreement with the expected charge exchange decay lifetimes for H(+), O(+), and He(+) in the energy and L-value range of the data. This inference technique, thus, establishes the presence of measurable and appreciable quantities of oxygen and helium ions as well as protons in the storm-time ring current. Indications that He(+) may also be present under these same conditions were found
Motions of charged particles in the Magnetosphere under the influence of a time-varying large scale convection electric field
The motions of charged particles under the influence of the geomagnetic and electric fields were quite complex in the region of the inner magnetosphere. The Volland-Stern type large scale convection electric field was used successfully to predict both the plasmapause location and particle enhancements determined from Explorer 45 measurements. A time dependence in this electric field was introduced based on the variation in Kp for actual magnetic storm conditions. The particle trajectories were computed as they change in this time-varying electric field. Several storm fronts of particles of different magnetic moments were allowed to be injected into the inner magnetosphere from L = 10 in the equatorial plane. The motions of these fronts are presented in a movie format
Real-Time Operating System/360
RTOS has a cost savings advantage for real-time applications, such as those with random inputs requiring a flexible data routing facility, display systems simplified by a device independent interface language, and complex applications needing added storage protection and data queuing
Image-based Recommendations on Styles and Substitutes
Humans inevitably develop a sense of the relationships between objects, some
of which are based on their appearance. Some pairs of objects might be seen as
being alternatives to each other (such as two pairs of jeans), while others may
be seen as being complementary (such as a pair of jeans and a matching shirt).
This information guides many of the choices that people make, from buying
clothes to their interactions with each other. We seek here to model this human
sense of the relationships between objects based on their appearance. Our
approach is not based on fine-grained modeling of user annotations but rather
on capturing the largest dataset possible and developing a scalable method for
uncovering human notions of the visual relationships within. We cast this as a
network inference problem defined on graphs of related images, and provide a
large-scale dataset for the training and evaluation of the same. The system we
develop is capable of recommending which clothes and accessories will go well
together (and which will not), amongst a host of other applications.Comment: 11 pages, 10 figures, SIGIR 201
Meanders and the Temperley-Lieb algebra
The statistics of meanders is studied in connection with the Temperley-Lieb
algebra. Each (multi-component) meander corresponds to a pair of reduced
elements of the algebra. The assignment of a weight per connected component
of meander translates into a bilinear form on the algebra, with a Gram matrix
encoding the fine structure of meander numbers. Here, we calculate the
associated Gram determinant as a function of , and make use of the
orthogonalization process to derive alternative expressions for meander numbers
as sums over correlated random walks.Comment: 85p, uuencoded, uses harvmac (l mode) and epsf, 88 figure
Ring current particle distributions during the magnetic storms of 16-18 December 1971
In an effort to summarize the constrasting development of the stormtime ring currents during the December 16-18, 1971 magnetic storms, maps were drawn indicating the proton energy density spatial/temporal distributions. The maps contain distributions for the 5 to 138 keV protons for each of seven orbits. The first storm was not characteristic of a single substorm nor a fully developed magnetic storm, but it was comprised of a sudden commencement, a positive phase, and multiple substorms producing a small depression in the magnetic field. The second storm was classical in development with a short two hour growth phase. Energy density distribution constrasts for the two storms show the second storm displayed three dominant features over the first storm. They were: (1) the intensities were 2 1/2 times larger, (2) the depths of penetration were 1/2 to 1 Reynolds number lower, and (3) the distribution became symmetric
EXAMINATION OF GLUTEAL MUSCLE FIRING and KINETICS OF THE LOWER EXTREMITY DURING THE WINDMILL SOFTBALL PITCH
The purpose of this study was to examine the muscle activation and kinetic data of the lower extremity during the windmill softball pitch. Limited research has documented the lower extremity in the windmill softball pitch. Seven female post-pubescent softball players volunteered for the study. Pitchers were analyzed with surface electromyography and motion analysis software. There was no relationship observed between gluteal activation and ground reaction forces at SFP and maximum force. Only one investigation prior to this study reported ground reaction forces of windmill softball pitchers, however they did not examine the EMG activity
Long-term Variability of HCO Masers in Star-forming Regions
We present results of a multi-epoch monitoring program on variability of
6cm formaldehyde (HCO) masers in the massive star forming region
NGC7538IRS1 from 2008 to 2015 conducted with the GBT, WSRT, and
VLA. We found that the similar variability behaviors of the two formaldehyde
maser velocity components in NGC7538IRS1 (which was pointed out by
Araya and collaborators in 2007) have continued. The possibility that the
variability is caused by changes in the maser amplification path in regions
with similar morphology and kinematics is discussed. We also observed
12.2GHz methanol and 22.2GHz water masers toward
NGC7538IRS1. The brightest maser components of CHOH and HO
species show a decrease in flux density as a function of time. The brightest
HCO maser component also shows a decrease in flux density and has a similar
LSR velocity to the brightest HO and 12.2GHz CHOH masers. The line
parameters of radio recombination lines and the 20.17 and 20.97GHz CHOH
transitions in NGC7538IRS1 are also reported. In addition, we
observed five other 6cm formaldehyde maser regions. We found no evidence of
significant variability of the 6cm masers in these regions with respect to
previous observations, the only possible exception being the maser in
G29.960.02. All six sources were also observed in the HCO
isotopologue transition of the 6cm HCO line; HCO absorption
was detected in five of the sources. Estimated column density ratios
[HCO]/[HCO] are reported.Comment: 29 pages, 9 figure
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