66,681 research outputs found
Prototype Graphs for radiative Corrections to Polarized Chargino or Neutralino Production in Electron-Positron Annihilation
We present the contributions from all types of one-loop corrections to the
scattering amplitude for the pair production of polarized charginos or
neutralinos from polarized electron-positron annihilation. The contributions
are classified in terms of ``prototypes'' distinguished by the number of
particles inside the loops and their spins. The results are quoted in terms of
the Veltman-Passarino functions in terms of general couplings and internal
masses. The results can therefore be applied to any supersymmetric extension of
the Standard Model or indeed to any polarized fermion pair production process
in electron-positron annihilation.Comment: LATEX 38 pages, 26 figure
A hybrid layout algorithm for sub-quadratic multidimensional scaling
Many clustering and layout techniques have been used for structuring and visualising complex data. This paper is inspired by a number of such contemporary techniques and presents a novel hybrid approach based upon stochastic sampling, interpolation and spring models. We use Chalmers' 1996 O(N/sup 2/) spring model as a benchmark when evaluating our technique, comparing layout quality and run times using data sets of synthetic and real data. Our algorithm runs in O(N/spl radic/N) and executes significantly faster than Chalmers' 1996 algorithm, whilst producing superior layouts. In reducing complexity and run time, we allow the visualisation of data sets of previously infeasible size. Our results indicate that our method is a solid foundation for interactive and visual exploration of data
Coordinating views for data visualisation and algorithmic profiling
A number of researchers have designed visualisation systems that consist of multiple components, through which data and interaction commands flow. Such multistage (hybrid) models can be used to reduce algorithmic complexity, and to open up intermediate stages of algorithms for inspection and steering. In this paper, we present work on aiding the developer and the user of such algorithms through the application of interactive visualisation techniques. We present a set of tools designed to profile the performance of other visualisation components, and provide further functionality for the exploration of high dimensional data sets. Case studies are provided, illustrating the application of the profiling modules to a number of data sets. Through this work we are exploring ways in which techniques traditionally used to prepare for visualisation runs, and to retrospectively analyse them, can find new uses within the context of a multi-component visualisation system
Thirty lessons in outlining for fourth grade
Thesis (Ed.M.)--Boston Universit
Playful expressions of one-year-old chimpanzee infants in social and solitary play contexts
Knowledge of the context and development of playful expressions in chimpanzees is limited because research has tended to focus on social play, on older subjects, and on the communicative signaling function of expressions. Here we explore the rate of playful facial and body expressions in solitary and social play, changes from 12- to 15-months of age, and the extent to which social partners match expressions, which may illuminate a route through which context influences expression. Naturalistic observations of seven chimpanzee infants (Pan troglodytes) were conducted at Chester Zoo, UK (n = 4), and Primate Research Institute, Japan (n = 3), and at two ages, 12 months and 15 months. No group or age differences were found in the rate of infant playful expressions. However, modalities of playful expression varied with type of play: in social play, the rate of play faces was high, whereas in solitary play, the rate of body expressions was high. Among the most frequent types of play, mild contact social play had the highest rates of play faces and multi-modal expressions (often play faces with hitting). Social partners matched both infant play faces and infant body expressions, but play faces were matched at a significantly higher rate that increased with age. Matched expression rates were highest when playing with peers despite infant expressiveness being highest when playing with older chimpanzees. Given that playful expressions emerge early in life and continue to occur in solitary contexts through the second year of life, we suggest that the play face and certain body behaviors are emotional expressions of joy, and that such expressions develop additional social functions through interactions with peers and older social partners
Toward Simultaneous Velocity and Density Measurements Using FLEET and Laser Rayleigh Scattering
Femtosecond laser electronic excitation tagging (FLEET) velocimetry and laser Rayleigh scattering are conducted concurrently and are evaluated for their suitability to measure velocity and density simultaneously in NASA Langleys 0.3-m Transonic Cryogenic Tunnel. FLEET velocimetry measurements are shown to be accurate to within 1.5 percent of the measured velocity throughout the facility testing envelope and exhibit a zero-velocity precision of 0.4 m/s. Rayleigh scattering density measurements indicate a characteristically linear dependence on flow density while having an accuracy within 5.4 percent of the measured density and a precision less than or equal to 6 percent. The preliminary assessment indicates that the joint technique would be advantageous for deployment in high-pressure, cryogenic test facilities
Optimal payload rate limit algorithm for zero-G manipulators
An algorithm for continuously computing safe maximum relative velocities for two bodies joined by a manipulator is discussed. The maximum velocities are such that if the brakes are applied at that instant, the ensuing travel between the bodies will be less than or equal to a predetermined amount. An improvement in the way this limit is computed for space manipulators is shown. The new method is explained, test cases are posed, and the results of these tests are displayed and discussed
Borel singularities at small x
D.I.S. at small Bjorken is considered within the dipole cascade
formalism. The running coupling in impact parameter space is introduced in
order to parametrize effects that arise from emission of large size dipoles.
This results in a new evolution equation for the dipole cascade. Strong
coupling effects are analyzed after transforming the evolution equation in
Borel () space. The Borel singularities of the solution are discussed first
for the universal part of the dipole cascade and then for the specific process
of D.I.S. at small . In the latter case the leading infrared renormalon is
at indicating the presence of power corrections for the
small- structure functions.Comment: 5 pages, Latex (Talk presented at DIS'97, Chicago, IL
H{\alpha} Imaging of Nearby Seyfert Host Galaxies
We used narrowband interference filters with the CCD imaging camera on the
Nickel 1.0 meter telescope at Lick Observatory to observe 31 nearby (z < 0.03)
Seyfert galaxies in the 12 {\mu}m Active Galaxy Sample. We obtained pure
emission line images of each galaxy in order to separate H{\alpha} emission
from the nucleus from that of the host galaxy. The extended H{\alpha} emission
is expected to be powered by newly formed hot stars, and correlates well with
other indicators of current star formation in these galaxies: 7.7 {\mu}m PAH,
far-infrared, and radio luminosity. Relative to what would be expected from
recent star formation, there is a 0.8 dex excess of radio emission in our
Seyfert galaxies. The nuclear H{\alpha} luminosity is dominated by the AGN, and
is correlated with the hard X-ray luminosity. There is an upward offset of 1
dex in this correlation for the Seyfert 1s due to a strong contribution from
the Broad Line Region. We found a correlation between star formation rate and
AGN luminosity. In spite of selection effects, we concluded that the absence of
bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly
significant. We used our measured spatial distributions of H{\alpha} emission
to determine what these Seyfert galaxies would look like when observed through
fixed apertures at high redshifts. Although all would be detectable emission
line galaxies at any redshift, most would appear dominated by HII region
emission. Only the most luminous AGN would still be identified at z~0.3.Comment: 13 pages, 11 figures, accepted for publication in Ap
- …