22,792 research outputs found
A cometary ion mass spectrometer
The development of flight suitable analyzer units for that part of the GIOTTO Ion Mass Spectrometer (IMS) experiment designated the High Energy Range Spectrometer (HERS) is discussed. Topics covered include: design of the total ion-optical system for the HERS analyzer; the preparation of the design of analyzing magnet; the evaluation of microchannel plate detectors and associated two-dimensional anode arrays; and the fabrication and evaluation of two flight-suitable units of the complete ion-optical analyzer system including two-dimensional imaging detectors and associated image encoding electronics
The HI Chronicles of LITTLE THINGS BCDs: Evidence for External Perturbations in the Morphology and Kinematics of Haro 29 and Haro 36
We analyze high angular and velocity resolution HI-line data of two LITTLE
THINGS (1) blue compact dwarfs (BCDs): Haro 29 and Haro 36. Both of these BCDs
are disturbed morphologically and kinematically. Haro 29's HI data reveal a
kinematic major axis that is offset from the optical major axis, and a
disturbed outer HI component, indicating that Haro 29 may have had a past
interaction. Position-velocity diagrams of Haro 36 indicate that it has two
kinematically separate components at its center and a likely tidal tail in
front of the galaxy. We find that Haro 36 most likely had an interaction in the
past, is currently interacting with an unknown companion, or is a merger
remnant. (1) "Local Irregulars That Trace Luminosity Extremes The HI Nearby
Galaxy Survey" http://www2.lowell.edu/users/dah/littlethings/index.htmlComment: To be published in The Astronomical Journa
The role of Guanxi on Chinese leadership innovation:the pilot study on the electric motor sector
This research aims to examine the existence and nature of complex business-social relationships in the Chinese context (Guanxi) and evaluate how these relationships influence the behaviors of managers in State-owned Chinese engineering firms. Research on Guanxi is comprehensive though little work investigates internal influences and how internal relationships may mirror or replicate external Guanxi. This study uses a snowball sample of 66 senior managers across the key functional disciplines in typical large Chinese firms and explores how often strategic level problems in the firm are solved through relationships outside, inside or between the companies. Do Guanxi networks penetrate the organization itself and are there relationships that are unique to internal networks? The research finds that problem solving at strategic levels are often through internal and external networks, rather than internal management structures, but also that different problems complexities typically demonstrate unique problem-solving networks. The research identifies three different forms that these relationships take: Internal, inter-firm and hybrid relationship modes. Implications for this work suggest problem solving in Chinese firms is enhanced through cooperation and mutual respect, and likely to be inhibited by traditional Western approaches to management
Diffuse gamma radiation
An examination of the intensity, energy spectrum, and spatial distribution of the diffuse gamma-radiation observed by SAS-2 satellite away from the galactic plane in the energy range above 35 MeV has shown that it consists of two components. One component is generally correlated with galactic latitudes, the atomic hydrogen column density was deduced from 21 cm measurements, and the continuum radio emission, believed to be synchrotron emission. It has an energy spectrum similar to that in the plane and joins smoothly to the intense radiation from the plane. It is therefore presumed to be of galactic origin. The other component is apparently isotropic, at least on a coarse scale, and has a steep energy spectrum. No evidence is found for a cosmic ray halo surrounding the galaxy in the shape of a sphere or oblate spheroid with galactic dimensions. Constraints for a halo model with significantly larger dimensions are set on the basis of an upper limit to the gamma-ray anisotropy
Two quantum Simpson's paradoxes
The so-called Simpson's "paradox", or Yule-Simpson (YS) effect, occurs in
classical statistics when the correlations that are present among different
sets of samples are reversed if the sets are combined together, thus ignoring
one or more lurking variables. Here we illustrate the occurrence of two
analogue effects in quantum measurements. The first, which we term
quantum-classical YS effect, may occur with quantum limited measurements and
with lurking variables coming from the mixing of states, whereas the second,
here referred to as quantum-quantum YS effect, may take place when coherent
superpositions of quantum states are allowed. By analyzing quantum measurements
on low dimensional systems (qubits and qutrits), we show that the two effects
may occur independently, and that the quantum-quantum YS effect is more likely
to occur than the corresponding quantum-classical one. We also found that there
exist classes of superposition states for which the quantum-classical YS effect
cannot occur for any measurement and, at the same time, the quantum-quantum YS
effect takes place in a consistent fraction of the possible measurement
settings. The occurrence of the effect in the presence of partial coherence is
discussed as well as its possible implications for quantum hypothesis testing.Comment: published versio
Scattering properties of Venus' surface
Radar backscatter functions Sigma-(carat)(sub 0)(phi) for incidence angles between 0 less than or equal to phi less than or equal to 4-10 deg were derived from Magellan altimetry radar echoes. The procedure includes constrained solution of a system of simultaneous equations for which the echo-spectrum and echo time profile are inputs. A practical and workable set of constraints was applied; optimization and improved results are expected as the analysis matures. The scattering functions yield information on small-scale surface structures (tens of centimeters to tens of meters) but averaged over hundreds of sq km. RMS surface slopes derived from fits of analytic functions to the Sigma-(carat)(sub 0)(phi) results were converted to map form and show patterns similar to those reported using other techniques. While all three forms are found on Venus, fit residuals imply that an exponential scattering function matches data better than either the Hagfors or Gaussian form in most areas, although the Hagfors function may be a better descriptor at some sites. Limited study of image data indicates that average backscatter cross section, and possibly its slope, can be derived at oblique angles (17 deg less than or equal to phi less than or equal to 45 deg). Offsets of the echo peak in altimetry spectra are surprisingly common and are loosely correlated with Venus topography, but no cause for this phenomenon was identified
Considerations for the design of an onboard air traffic situation display
The basic concept of remoting information to the cockpit is used to design and develop a computerized airborne traffic situation display device that automatically selects and presents segments of a controller's scope to the aircraft pilot via a narrow band digital data link. These data are integrated with aircraft heading and navigation information to provide a display useful in congested air space. The display can include alphanumerical symbols, air route maps, and controller instructions
The HI Chronicles of LITTLE THINGS BCDs II: The Origin of IC 10's HI Structure
In this paper we analyze Very Large Array (VLA) telescope and Green Bank
Telescope (GBT) atomic hydrogen (HI) data for the LITTLE THINGS(1) blue compact
dwarf galaxy IC 10. The VLA data allow us to study the detailed HI kinematics
and morphology of IC 10 at high resolution while the GBT data allow us to
search the surrounding area at high sensitivity for tenuous HI. IC 10's HI
appears highly disturbed in both the VLA and GBT HI maps with a kinematically
distinct northern HI extension, a kinematically distinct southern plume, and
several spurs in the VLA data that do not follow the general kinematics of the
main disk. We discuss three possible origins of its HI structure and kinematics
in detail: a current interaction with a nearby companion, an advanced merger,
and accretion of intergalactic medium. We find that IC 10 is most likely an
advanced merger or a galaxy undergoing accretion.
1:Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy
Survey; https://science.nrao.edu/science/surveys/littlethingsComment: 36 pages, 17 figures, accepted for publication in The Astronomical
Journa
Constraints on radiative decay of the 17-keV neutrino from COBE Measurements
It is shown that, for a nontrivial radiative decay channel of the 17-keV
neutrino, the photons would distort the microwave background radiation through
ionization of the universe. The constraint on the branching ratio of such
decays from COBE measurements is found to be more stringent than that from
other considerations. The limit on the branching ratio in terms of the Compton
parameter is for an
universe.Comment: 7 pages. (figures will be sent on request) (To appear in Phys. Rev.
D.
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