1,066 research outputs found
The Department of Consumers
In 1872, Congress began protecting the American consumer by enacting legislation to prevent mail fraud. From this modest beginning, the consumer protection activities of the federal government have proliferated until today there are at least 33 government agencies engaged in 296 consumer protection activities. In 1961, the estimated annual expenditures by the federal government for direct consumer protection activities totaled 272 million dollars and the number of full-time federal employees engaged in such activities was almost 22,000. Expenditures for consumer advancement, a broader concept, were estimated at 681 million dollars in 1961 and the number of full time federal employees assigned to such work was nearly 43,000.
Current figures for such expenditures and employees would surely be substantially greater. This vast expenditure of money and time was not coordinated or administered by any single department or agency of the federal government. The activities were conducted independently except when independent federal agencies, in their own discretion, found it advisable to consult among themselves
Anisotropic k-essence cosmologies
We investigate a Bianchi type-I (BTI) cosmology with k essence and find the
set of models which dissipate the initial anisotropy. There are cosmological
models with extended tachyon fields and k essence having constant bariotropic
index. We obtain the conditions leading to a regular bounce of the average
geometry and the residual anisotropy on the bounce. For constant potential, we
develop purely kinetic k-essence models which are dust dominated in their early
stages, dissipate the initial anisotropy and end in a stable de Sitter
accelerated expansion scenario. We show that linear k field and polynomial
kinetic function models evolve asymptotically to Friedmann-Robertson-Walker
(FRW) cosmologies. The linear case is compatible with an asymptotic potential
interpolating between , in the shear dominated
regime, and at late time. In the polynomial case, the
general solution contains cosmological models with an oscillatory average
geometry. For linear k essence, we find the general solution in the BTI
cosmology when the k field is driven by an inverse square potential. This model
shares the same geometry than a quintessence field driven by an exponential
potential.Comment: 19 pages, REVTeX
Multi-frequency and multi-attribute GPR data fusion based on 2-D wavelet transform
High frequency GPR signals offer high resolution while low frequency GPR signals offer greater depth of penetration. Effective fusion of multiple frequencies can combine the advantages of both. In addition, GPR attribute analysis can improve subsurface imaging, but a single attribute can only partly highlight details of different physical and geometrical properties of subsurface potential targets. In order to overcome these challenges, we implement an advanced multi-frequency and multi-attribute GPR data fusion approach based on 2-D wavelet transform utilizing a dynamic fusion weight scheme derived from edge detection algorithm, which is tested on data from a small glacier in the north-eastern Alps by 250 & 500 MHz central frequency antennas. Besides, information entropy and spatial frequency are developed as quantitative evaluation parameters to analyze the fusion outcomes. The results demonstrate that the proposed approach can enhance the efficiency and scope of GPR data interpretation in an automatic and objective way
Anyons as quon particles
The momentum operator representation of nonrelativistic anyons is developed
in the Chern - Simons formulation of fractional statistics. The connection
between anyons and the q-deformed bosonic algebra is established.Comment: 10 pages,Late
The QCD/SM Working Group: Summary Report
This Report documents the results obtained by the Working Group on Quantum
ChromoDynamics and the Standard Model for the Workshop ``Physics at TeV
Colliders'', Les Houches, France, 21 May - 1 June 2001. The account of
uncertainties in Parton Distribution Functions is reviewed. Progresses in the
description of multiparton final states at Next-to-Leading Order and the
extension of calculations for precision QCD observables beyond this order are
summarized. Various issues concerning the relevance of resummation for
observables at TeV colliders is examined. Improvements to algorithms of jet
reconstruction are discussed and predictions for diphoton and photon pi-zero
production at the LHC are made for kinematic variables of interest regarding
searches for a Higgs boson decaying into two photons. Finally, several
improvements implemented in Monte-Carlo event generators are documented
An ATM/Chk2-mediated DNA damage responsive signaling pathway suppresses Epstein-Barr virus transformation of primary human B cells
SummaryEpstein-Barr virus (EBV), an oncogenic herpesvirus that causes human malignancies, infects and immortalizes primary human B cells in vitro into indefinitely proliferating lymphoblastoid cell lines, which represent a model for EBV-induced tumorigenesis. The immortalization efficiency is very low, suggesting that an innate tumor suppressor mechanism is operative. We identify the DNA damage response (DDR) as a major component of the underlying tumor suppressor mechanism. EBV-induced DDR activation was not due to lytic viral replication, nor did the DDR marks colocalize with latent episomes. Rather, a transient period of EBV-induced hyperproliferation correlated with DDR activation. Inhibition of the DDR kinases ATM and Chk2 markedly increased transformation efficiency of primary B cells. Further, the viral latent oncoprotein EBNA3C was required to attenuate the EBV-induced DDR. We propose that heightened oncogenic activity in early cell divisions activates a growth-suppressive DDR that is attenuated by viral latency products to induce cell immortalization
Two-Loop Quantum Corrections of Scalar QED with Non-Minimal Chern-Simons Coupling
We investigate two-loop quantum corrections to non-minimally coupled
Maxwell-Chern-Simons theory. The non-minimal gauge interaction represents the
magnetic moment interaction between the charged scalar and the electromagnetic
field. We show that the one-loop renormalizability of the theory found in
previous work does not survive to the two-loop level. However, with an
appropriate choice of the non-minimal coupling constant, it is possible to
renormalize the two-loop effective potential and hence render it potentially
useful for a detailed analysis of spontaneous symmetry breaking induced by
radiative corrections.Comment: 29 pages, including 21 figures. One author added, some formulae
corrected and references adde
Planar QED at finite temperature and density: Hall conductivity, Berry's phases and minimal conductivity of graphene
We study 1-loop effects for massless Dirac fields in two spatial dimensions,
coupled to homogeneous electromagnetic backgrounds, both at zero and at finite
temperature and density. In the case of a purely magnetic field, we analyze the
relationship between the invariance of the theory under large gauge
transformations, the appearance of Chern-Simons terms and of different Berry's
phases. In the case of a purely electric background field, we show that the
effective Lagrangian is independent of the chemical potential and of the
temperature. More interesting: we show that the minimal conductivity, as
predicted by the quantum field theory, is the right multiple of the
conductivity quantum and is, thus, consistent with the value measured for
graphene, with no extra factor of pi in the denominator.Comment: 27 pages, no figures. Minor misprints corrected. Final version, to
appear in J. Phys. A: Math. Ge
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