1,813 research outputs found
Oxygen and hydrogen ion abundance in the near-Earth magnetosphere: Statistical results on the response to the geomagnetic and solar wind activity conditions
The composition of ions plays a crucial role for the fundamental plasma
properties in the terrestrial magnetosphere. We investigate the
oxygen-to-hydrogen ratio in the near-Earth magnetosphere from -10 RE<XGSE}< 10
RE. The results are based on seven years of ion flux measurements in the energy
range ~10 keV to ~955 keV from the RAPID and CIS instruments on board the
Cluster satellites. We find that (1) hydrogen ions at ~10 keV show only a
slight correlation with the geomagnetic conditions and interplanetary magnetic
field changes. They are best correlated with the solar wind dynamic pressure
and density, which is an expected effect of the magnetospheric compression; (2)
~10 keV O+ ion intensities are more strongly affected during disturbed phase of
a geomagnetic storm or substorm than >274 keV O+ ion intensities, relative to
the corresponding hydrogen intensities; (3) In contrast to ~10 keV ions, the
>274 keV O+ ions show the strongest acceleration during growth phase and not
during the expansion phase itself. This suggests a connection between the
energy input to the magnetosphere and the effective energization of energetic
ions during growth phase; (4) The ratio between quiet and disturbed times for
the intensities of ion ionospheric outflow is similar to those observed in the
near-Earth magnetosphere at >274 keV. Therefore, the increase of the energetic
ion intensity during disturbed time is more likely due to the intensification
than to the more effective acceleration of the ionospheric source. In
conclusion, the energization process in the near-Earth magnetosphere is mass
dependent and it is more effective for the heavier ions
Getting patients in the door: medical appointment reminder preferences
Between 23% and 34% of outpatient appointments are missed annually. Patients who frequently miss medical appointments have poorer health outcomes and are less likely to use preventive health care services. Missed appointments result in unnecessary costs and organizational inefficiencies. Appointment reminders may help reduce missed appointments; particular types may be more effective than other types. We used a survey with a discrete choice experiment (DCE) to learn why individuals miss appointments and to assess appointment reminder preferences
Evaluation of nonmetallic thermal protection materials for the manned space shuttle. Volume 1, task 1: Assessment of technical risks associated with utilization of nonmetallic thermal protection system
Technical problems of design and flight qualification of the proposed classes of surface insulation materials and leading edge materials were reviewed. A screening test plan, a preliminary design data test plan and a design data test plan were outlined. This program defined the apparent critical differences between the surface insulators and the leading edge materials, structuring specialized screening test plans for each of these two classes of materials. Unique testing techniques were shown to be important in evaluating the structural interaction aspects of the surface insulators and a separate task was defined to validate the test plan. In addition, a compilation was made of available information on proposed material (including metallic TPS), previous shuttle programs, pertinent test procedures, and other national programs of merit. This material was collected and summarized in an informally structured workbook
The Grizzly, March 22, 1985
WVOU to Broadcast to Wismer • U.C. Receives $32,000 in Grants • Letter: Thoughtless Student Hurts Feelings • New Faces, New Places • Woman\u27s Club Events • Independent Eye Stages Macbeth • Meistersingers to Present Spring Program • Stevenson Resigns as Golf Coachhttps://digitalcommons.ursinus.edu/grizzlynews/1136/thumbnail.jp
Methodology for designing accelerated aging tests for predicting life of photovoltaic arrays
A methodology for designing aging tests in which life prediction was paramount was developed. The methodology builds upon experience with regard to aging behavior in those material classes which are expected to be utilized as encapsulant elements, viz., glasses and polymers, and upon experience with the design of aging tests. The experiences were reviewed, and results are discussed in detail
An Unexpectedly Swift Rise in the Gamma-ray Burst Rate
The association of long gamma-ray bursts with supernovae naturally suggests
that the cosmic GRB rate should trace the star formation history. Finding
otherwise would provide important clues concerning these rare, curious
phenomena. Using a new estimate of Swift GRB energetics to construct a sample
of 36 luminous GRBs with redshifts in the range z=0-4, we find evidence of
enhanced evolution in the GRB rate, with ~4 times as many GRBs observed at z~4
than expected from star formation measurements. This direct and empirical
demonstration of needed additional evolution is a new result. It is consistent
with theoretical expectations from metallicity effects, but other causes remain
possible, and we consider them systematically.Comment: 4 pages, 4 figures; minor changes to agree with published versio
Astronomical Site Ranking Based on Tropospheric Wind Statistics
We present comprehensive and reliable statistics of high altitude wind speeds
and the tropospheric flows at the location of five important astronomical
observatories. Statistical analysis exclusively of high altitude winds point to
La Palma as the most suitable site for adaptive optics, with a mean value of
22.13 m/s at the 200 mbar pressure level. La Silla is at the bottom of the
ranking, with the largest average value 200 mbar wind speed(33.35 m/s). We have
found a clear annual periodicity of high altitude winds for the five sites in
study. We have also explored the connection of high to low altitude atmospheric
winds as a first approach of the linear relationship between the average
velocity of the turbulence and high altitude winds (Sarazin & Tokovinin 2001).
We may conclude that high and low altitude winds show good linear relationships
at the five selected sites. The highest correlation coefficients correspond to
Paranal and San Pedro Martir, while La Palma and La Silla show similar high to
low altitude wind connection. Mauna Kea shows the smallest degree of
correlation, which suggests a weaker linear relationship. Our results support
the idea of high altitude winds as a parameter for rank astronomical sites in
terms of their suitability for adaptive optics, although we have no evidence
for adopting the same linear coefficient at different sites. The final value of
this linear coefficient at a particular site could drastically change the
interpretation of high altitude wind speeds as a direct parameter for site
characterization.Comment: 18 pages, 5 figures. Accepted in MNRA
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