4,546 research outputs found
Utilizing the Updated Gamma-Ray Bursts and Type Ia Supernovae to Constrain the Cardassian Expansion Model and Dark Energy
We update gamma-ray burst (GRB) luminosity relations among certain spectral
and light-curve features with 139 GRBs. The distance modulus of 82 GRBs at
can be calibrated with the sample at by using the cubic
spline interpolation method from the Union2.1 Type Ia supernovae (SNe Ia) set.
We investigate the joint constraints on the Cardassian expansion model and dark
energy with 580 Union2.1 SNe Ia sample () and 82 calibrated GRBs data
(). In CDM, we find that adding 82 high-\emph{z} GRBs to
580 SNe Ia significantly improves the constrain on
plane. In the Cardassian expansion model, the
best fit is and
, which is consistent with the CDM cosmology in the
confidence region. We also discuss two dark energy models in which
the equation of state is parametrized as and
, respectively. Based on our analysis, we see that our
Universe at higher redshift up to is consistent with the concordance
model within confidence level.Comment: 17 pages, 6 figures, 2 tables; accepted for publication in Advances
in Astronomy, special issue on Gamma-Ray Burst in Swift and Fermi Era. arXiv
admin note: text overlap with arXiv:0802.4262, arXiv:0706.0938 by other
author
Analysis of overburden layer thickness influence on dynamic response of concrete face rock-fill dam
In the past, when performing dynamic response analysis of dams on deep overburden, the dam body and the overburden have often been discussed separately. In this paper, the overburden and the dam body are considered as a whole, and the dynamic response analysis is carried out by using a completely nonlinear dynamic analysis method. From the acceleration of the earth’s surface, the displacement of the dam, and the stress distribution of the panel, the dynamic response of the structure is shown to increase first and then decrease with increasing cover thickness, and the overburden layer thickness corresponding to the extreme point is called the critical thickness. The results obtained in this study can provide a design basis for a face rock-fill dam built on a deep overburden layer
Improving Dual-Purpose Winter Wheat in the Southern Great Plains of the United States
This chapter covers the production and breeding status of winter wheat (Triticum aestivum L.) used for early-season animal grazing and late-season grain production in the Southern Great Plains of the United States. Besides, in the chapter, the current production status and needs, the drawbacks of current cultivars, breeding strategies of the crop, novel genomics tools, and sensor technologies that can be used to improve dual-purpose winter wheat cultivars were presented. We will focus on traits that are, in general, not required by cultivars used for grain-only production but are critical for cool-season forage production
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