2,390 research outputs found
Scale dependence of in N-flation
Adopting the horizon-crossing approximation, we derive the spectral index of
in general N-flation model. Axion N-flation model is taken as a
typical model for generating a large which characterizes the size of
local form bispectrum. We find that its tilt is negligibly small
when all inflatons have the same potential, but a negative detectable
can be achieved in the axion N-flation with different decay
constants for different inflatons. The measurement of can be used
to support or falsify the axion N-flation in the near future.Comment: 15 pages, 2 figures; a subsection with detectable scale dependence of
f_NL added; more discussions added and version accepted for publication in
JCA
Investigation of foamed metals for application on space capsules annual report, 29 jun. 1963 - 15 aug. 1964
Foamed metal development for space capsules - brazing, variable density beam, thermal testing, mechanical tests, and machinin
A comparison study of atmospheric radiometric calibration methods for aerial thermograms
A comparison study was conducted to evaluate limitations of several atmospheric calibration techniques, including: Angular, Profile, and spectrally corrected and uncorrected LOWTRAN. To accomplish this, a thermal mapper was flown over a shoreline where water surface temperatures were measured coincidentally by a ground crew. The thermogram derived observed radiances were corrected using each of the atmospheric calibration methods so that ground surface temperatures could be predicted. The R.M.S. errors of these ground temperature predictions indicated that all calibration techniques yielded similar results at 1000-foot altitude. The error remained constant for the Profile and LOWTRAN calibration techniques to 6000-foot altitude, but the Angular results singularly indicated a pronounced altitude dependence in ground temperature prediction errors to 6000-foot altitude
Teaching Minimum Based Competency Test Skills to Secondary-Aged Learning Disabled Students Through The Use of Precision Teaching
This project investigated whether a precision teaching method used with learning disabled high school students (grades 9-12) could give them the skills needed to pass a minimum based competency test in the area of local, state and national government. The specific objective of this project was to determine if the use of precision teaching enabled the students to retain the facts needed to pass a competency test required for graduation. A multiple-baseline design across behaviors was used to show the effect of precision teaching in mastering the needed facts. The data from each baseline improved and surpassed the set criteria when the intervention was introduced. The Cache School District requires mastery level test score of 70% or higher for each competency test. The pretest scores of the students in this study ranged from 40% to 58%. When all three interventions were completed, the students\u27 test scores ranged from 92% to 100%, thus meeting and surpassing the school district\u27s mastery level
A non-Gaussian landscape
Primordial perturbations with wavelengths greater than the observable universe shift the effective background fields in our observable patch from their global averages over the inflating space. This leads to a landscape picture where the properties of our observable patch depend on its location and may significantly differ from the expectation values predicted by the underlying fundamental inflationary model. We show that if multiple fields are present during inflation, this may happen even if our horizon exit would be preceded by only a few e-foldings of inflation. Non-Gaussian statistics are especially affected: for example models of local non-Gaussianity predicting |f_NL|>> 10 over the entire inflating volume can have a probability up to a few tens of percent to generate a non-detectable bispectrum in our observable patch |fNL^{obs.}|<10. In this work we establish systematic connections between the observable local properties of primordial perturbations and the global properties of the inflating space which reflect the underlying high energy physics. We study in detail the implications of both a detection and non-detection of primordial non-Gaussianity by Planck, and discover novel ways of characterising the naturalness of different observational configurations
Scale-dependence of Non-Gaussianity in the Curvaton Model
We investigate the scale-dependence of f_NL in the self-interacting curvaton
model. We show that the scale-dependence, encoded in the spectral index
n_{f_NL}, can be observable by future cosmic microwave background observations,
such as CMBpol, in a significant part of the parameter space of the model. We
point out that together with information about the trispectrum g_NL, the
self-interacting curvaton model parameters could be completely fixed by
observations. We also discuss the scale-dependence of g_NL and its implications
for the curvaton model, arguing that it could provide a complementary probe in
cases where the theoretical value of n_{f_NL} is below observational
sensitivity.Comment: 14 pages, 5 figures, Eq.(10) correcte
Scale-Dependent Non-Gaussianity as a Generalization of the Local Model
We generalize the local model of primordial non-Gaussianity by promoting the
parameter fNL to a general scale-dependent function fNL(k). We calculate the
resulting bispectrum and the effect on the bias of dark matter halos, and thus
the extent to which fNL(k) can be measured from the large-scale structure
observations. By calculating the principal components of fNL(k), we identify
scales where this form of non-Gaussianity is best constrained and estimate the
overlap with previously studied local and equilateral non-Gaussian models.Comment: Accepted to JCAP. 22 pages, 4 figure
Inhomogeneous non-Gaussianity
We propose a method to probe higher-order correlators of the primordial
density field through the inhomogeneity of local non-Gaussian parameters, such
as f_NL, measured within smaller patches of the sky. Correlators between
n-point functions measured in one patch of the sky and k-point functions
measured in another patch depend upon the (n+k)-point functions over the entire
sky. The inhomogeneity of non-Gaussian parameters may be a feasible way to
detect or constrain higher-order correlators in local models of
non-Gaussianity, as well as to distinguish between single and multiple-source
scenarios for generating the primordial density perturbation, and more
generally to probe the details of inflationary physics.Comment: 16 pages, 2 figures; v2: Minor changes and references added. Matches
the published versio
Space Trajectory Error Analysis Program (STEAP) for halo orbit missions. Volume 2: Programmer's manual
The six month effort was responsible for the development, test, conversion, and documentation of computer software for the mission analysis of missions to halo orbits about libration points in the earth-sun system. The software consisting of two programs called NOMNAL and ERRAN is part of the Space Trajectories Error Analysis Programs. The program NOMNAL targets a transfer trajectory from earth on a given launch date to a specified halo orbit on a required arrival date. Either impulsive or finite thrust insertion maneuvers into halo orbit are permitted by the program. The transfer trajectory is consistent with a realistic launch profile input by the user. The second program ERRAN conducts error analyses of the targeted transfer trajectory. Measurements including range, doppler, star-planet angles, and apparent planet diameter are processed in a Kalman-Schmidt filter to determine the trajectory knowledge uncertainty
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