4,829 research outputs found
Holographic field theory models of dark energy in interaction with dark matter
We discuss two lagrangian interacting dark energy models in the context of
the holographic principle. The potentials of the interacting fields are
constructed. The models are compared with CMB distance information, baryonic
acoustic oscilations, lookback time and the Constitution supernovae sample. For
both models the results are consistent with a non vanishing interaction between
dark sectors - with more than three standard deviations of confidence for one
of them. Moreover, in both cases, the sign of coupling is consistent with dark
energy decaying into dark matter, alleviating the coincidence problem.Comment: arXiv admin note: substantial text overlap with arXiv:0912.399
Realistic Estimates of the Uncertainties and the Reliability Indices for Shallow Foundation Design Considering Seismic Loading
Risk and Reliability in Geotechnical Engineerin
Fan Loops Observed by IRIS, EIS and AIA
A comprehensive study of the physical parameters of active region fan loops
is presented using the observations recorded with the Interface Region Imaging
Spectrometer (IRIS), the EUV Imaging Spectrometer (EIS) on-board Hinode and the
Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager
(HMI) on-board the Solar Dynamics Observatory (SDO). The fan loops emerging
from non-flaring AR~11899 (near the disk-center) on 19th November, 2013 are
clearly discernible in AIA 171~{\AA} images and those obtained in \ion{Fe}{8}
and \ion{Si}{7} images using EIS. Our measurements of electron densities reveal
that the footpoints of these loops are approximately at constant pressure with
electron densities of 10.1 cm at
(\ion{O}{4}), and 8.9 cm at
(\ion{Si}{10}). The electron temperature diagnosed across the fan loops by
means of EM-Loci suggest that at the footpoints, there are two temperature
components at and 5.95, which are picked-up by IRIS lines
and EIS lines respectively. At higher heights, the loops are nearly isothermal
at , that remained constant along the loop. The measurement
of Doppler shift using IRIS lines suggests that the plasma at the footpoints of
these loops is predominantly redshifted by 2-3~km~s in \ion{C}{2},
10-15~km~s in \ion{Si}{4} and 15{--}20~km~s in \ion{O}{4},
reflecting the increase in the speed of downflows with increasing temperature
from to 5.15. These observations can be explained by low
frequency nanoflares or impulsive heating, and provide further important
constraints on the modeling of the dynamics of fan loops.Comment: Accepted for publication in The Astrophysical Journal; 8 Figures, 11
page
Correspondence between Loop-inspired and Braneworld Cosmology
Braneworld scenarios are motivated by string/M-theory and can be
characterized by the way in which they modify the conventional Friedmann
equations of Einstein gravity. An alternative approach to quantum gravity,
however, is the loop quantum cosmology program. In the semi-classical limit,
the cosmic dynamics in this scenario can also be described by a set of modified
Friedmann equations. We demonstrate that a dynamical correspondence can be
established between these two paradigms at the level of the effective field
equations. This allows qualitatively similar features between the two
approaches to be compared and contrasted as well as providing a framework for
viewing braneworld scenarios in terms of constrained Hamiltonian systems. As
concrete examples of this correspondence, we illustrate the relationships
between different cosmological backgrounds representing scaling solutions
Collaboration Versus Cheating
We outline how we detected programming plagiarism in an introductory online
course for a master's of science in computer science program, how we achieved a
statistically significant reduction in programming plagiarism by combining a
clear explanation of university and class policy on academic honesty reinforced
with a short but formal assessment, and how we evaluated plagiarism rates
before SIGand after implementing our policy and assessment.Comment: 7 pages, 1 figure, 5 tables, SIGCSE 201
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Nanodielectics (A "Universal" Panacea for Solving All Electrical Insualation Problems?)
This text summarizes the keynote presentation that is based on the full-length paper of the same title. Dr. Fréchette's oral presentation should not be seen as a summary of the “Brainstorm paper” but a glance at some major accomplishments, hinrances and still remaining questions relative to nanodielectrics. Are nanodielectrics a “universal” panacea? The answer to that question is no - but they've got a lot of potential
Measuring Market Valuation of Amman Stock Exchange Industrial Sectors: Tobin’s Q Ratio as Investors’ Market Performance Indicator
This research investigation purported to present the market valuation of Amman Stock Exchange Industrial Sectors utilizing the Tobin’s Q ratio to serve as performance indicator among Jordanian industrial firms. The most specific research objectives addressed in this research work were to evaluate the Amman Stock Exchange Industry market performance, present the trend in Q ratio valuation during the study period, and to recommend some guiding principles to enrich investors in making the right investment decisions. The research paper is anchored on the concepts of Chung and Pruitt (1994) who have developed a simple approximation of Tobin’s q. For the methodology, the researchers made use of the 49 sample companies from all industrial public traded company sectors listed in the Amman Stock Exchange (ASE) clustered based on the Amman Stock Exchange classification as published in their publications inclusive of 2008-2015. The sectors included the Pharmaceutical & Medical Industries, Chemical Industries, Paper & Cartoon Industries, Food & Beverage, Tobacco & Cigarettes, Mining & Extraction Industries, Engineering & Construction, Electrical Industries, Textile, and Leather & Clothing......
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