2,183 research outputs found
The swept angle retarding mass spectrometer: Initial results from the Michigan auroral probe sounding rocket
Data from a sounding rocket flight of the swept angle retarding ion mass spectrometer (SARIMS) are presented to demonstrate the capability of the instrument to make measurements of thermal ions which are differential in angle, energy, and mass. The SARIMS was flown on the Michigan auroral probe over regions characterized first by discrete auroral arcs and later by diffuse precipitation. The instrument measured the temperature, densities, and flow velocities of the ions NO(+) and O(+). Measured NO(+) densities ranged from 10 to the 5th power up to 3 x 10 to the 5th power ions/cu cm, while the measured O(+) densities were a factor of 5-10 less. Ion temperatures ranged from 0.15 up to 0.33 eV. Eastward ion flows approximately 0.5 km/sec were measured near the arcs, and the observed flow magnitude decreased markedly inside the arcs
Instrument manual for the retarding ion mass spectrometer on Dynamics Explorer-1
The retarding ion mass spectrometer (RIMS) for Dynamics Explorer-1 is an instrument designed to measure the details of the thermal plasma distribution. It combines the ion temperature determining capability of the retarding potential analyzer with the compositional capabilities of the mass spectrometer and adds multiple sensor heads to sample all directions relative to the spacecraft ram direction. This manual provides a functional description of the RIMS, the instrument calibration, and a description of the commands which can be stored in the instrument logic to control its operation
Report from magnetospheric science
By the early 1990s, magnetospheric physics will have progressed primarily through observations made from Explorer-class spacecraft, sounding rockets, ground based facilities, and shuttle based experiments. The global geospace science (GGS) element of the International Solar Terrestrial Physics program, when combined with contributions to the ESA Cluster mission and ground based and computer modeling programs, will form the basis for a major U.S. initiative in magnetospheric physics. The scientific objectives of the GGS program involve the study of energy transport throughout geospace. The Cluster mission will investigate turbulence and boundary phenomena in geospace, particularly at high latitudes on the dayside and in the region of the neutral sheet at geocentric distances of about 20 earth radii on the night side of the earth. The current state of knowledge is reviewed and the goals of these missions are briefly discussed
The retarding ion mass spectrometer on dynamics Explorer-A
An instrument designed to measure the details of the thermal plasma distribution combines the ion temperature-determining capability of the retarding potential analyzer with the compositional capabilities of the mass spectrometer and adds multiple sensor heads to sample all directions relative to the spacecraft ram directions. The retarding ion mass spectrometer, its operational modes and calibration are described as well as the data reduction plan, and the anticipated results
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Genetic expression of an amyloid peptide fragment and analysis of formylated products
The model amyloid peptide AAKLVFF was expressed as a His-tagged fusion protein with the immunoglobulin-binding domain B1 of streptococcal
protein G (GB1), a small (56 residues), stable, single-domain protein. It is shown that expression of this model amyloid peptide is possible and is
not hindered by aggregation. Formylation side reactions during the CNBr cleavage are investigated via synthesis of selectively formylated peptides
Interferometric Astrometry of Proxima Centauri and Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: Detection Limits for sub-Stellar Companions
We report on a sub-stellar companion search utilizing interferometric
fringe-tracking astrometry acquired with Fine Guidance Sensor 3 (FGS 3) on the
Hubble Space Telescope. Our targets were Proxima Centauri and Barnard's Star.
We obtain absolute parallax values for Proxima Cen pi_{abs} = 0.7687 arcsecond
and for Barnard's Star pi_{abs} = 0.5454 arcsecond.
Once low-amplitude instrumental systematic errors are identified and removed,
our companion detection sensitivity is less than or equal to one Jupiter mass
for periods longer than 60 days for Proxima Cen. Between the astrometry and the
radial velocity results we exclude all companions with M > 0.8M_{Jup} for the
range of periods 1 < P < 1000 days. For Barnard's Star our companion detection
sensitivity is less than or equal to one Jupiter mass for periods long er than
150 days. Our null results for Barnard's Star are consistent with those of
Gatewood (1995).Comment: 35 pages, 13 figures, to appear in August 1999 A
Petrology of the Early Cretaceous Sierra Nevada Batholith; the Stokes Mountain region, CA
Previous studies have shown that the early Cretaceous
batholith (130-110 Ma) contains the least chemically and
isotopically evolved lithologies of the composite Sierra
Nevada batholith.
Mapping at 1:24,000 of a 360 km^2 area
in the foothills ESE of Fresno (the Stokes Mountain region;
latitude 36°30') reveals a smoothly continuous range (SiO_2 = 44-78%) of calcic lithologies dominated by norites,
hornblende gabbros, quartz diorites, tonalites and
granodiorites
The influence of government ideology on monetary policy:New cross-country evidence based on dynamic heterogeneous panels
Using data of 23 OECD countries over the 1980–2005 period, we examine whether government ideology affects monetary policy, conditional on central bank independence. Unlike previous studies in this line of literature, we estimate central bank behavior using forward‐looking and real‐time data in Taylor rule models and use estimators that allow for heterogeneity across countries. Our models with heterogeneous slope coefficients for the full sample do not suggest partisan effects. We also do not find evidence that central bank behavior is conditioned by the interaction of the ideology of the incumbent government and the electoral calendar
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