297 research outputs found
Minimal Models of CFT on Z_N-Surfaces
The conformal field theory on a Z_N-surface is studied by mapping it on the
branched sphere. Using a coulomb gas formalism we construct the minimal models
of the theory.Comment: 16 pages, latex, no figures; two important early references on the
coset construction have been included; to appear in Mod. Phys. Let
Heroism and Wellbeing in the 21st Century: Applied and Emerging Perspectives
Offering a holistic take on an emerging field, this edited collection examines how heroism manifests, is appropriated, and is constructed in a broad range of settings and from a variety of disciplines and perspectives. Psychologists, educators, lawyers, researchers and cultural analysts consider how heroism intersects with wellbeing, and how we still use—and even abuse—heroism as a vehicle to thrive and prosper in the everyday and in the face of the most unbearable situations. Highlighting some of the most pressing issues in today’s world—including genocide, racism, deceitful business practices, bystanderism, mental health, unethical governance and the global refugee crisis—this book applies a critical psychological perspective in synthesizing the social construction of heroism and wellbeing, contributing to the development of global wellbeing indicators and measures.https://scholarship.richmond.edu/bookshelf/1321/thumbnail.jp
Estimation of Timing Resolution for Very Fast Time-Of-Flight Detectors in Monte Carlo Simulations
In PET imaging the depth of absorption in the
crystal contributes to the detection time uncertainty, which
impacts the time resolution of the scatter. In addition, affects
the nature of the timing distribution. It was found that when
Photon Travel Spread (PTS) in the crystal is the only factor
affecting the timing uncertainty, in which case, a Laplace kernel
might describe the measured data, more accurately. It was shown
that for crystals as thin as 20 mm the RMSE of the Laplace was
smaller than that of a Normal. While when PTS is combined
with an addition coincidence detection resolution (CDR) then,
a Normal achieves better RMSE, but with dependency on the
crystal size. Results in terms of CRC, of a simulated NEMA
phantom, confirmed that reconstruction using a Laplace kernel
can model the data better for thicker crystals
Applications of Partial Supersymmetry
I examine quantum mechanical Hamiltonians with partial supersymmetry, and
explore two main applications. First, I analyze a theory with a logarithmic
spectrum, and show how to use partial supersymmetry to reveal the underlying
structure of this theory. This method reveals an intriguing equivalence between
two formulations of this theory, one of which is one-dimensional, and the other
of which is infinite-dimensional. Second, I demonstrate the use of partial
supersymmetry as a tool to obtain the asymptotic energy levels in
non-relativistic quantum mechanics in an exceptionally easy way. In the end, I
discuss possible extensions of this work, including the possible connections
between partial supersymmetry and renormalization group arguments.Comment: 11 pages, harvmac, no figures; typo corrected in identifying info on
title pag
Greybody factors in a rotating black-hole background-II : fermions and gauge bosons
We study the emission of fermion and gauge boson degrees of freedom on the
brane by a rotating higher-dimensional black hole. Using matching techniques,
for the near-horizon and far-field regime solutions, we solve analytically the
corresponding field equations of motion. From this, we derive analytical
results for the absorption probabilities and Hawking radiation emission rates,
in the low-energy and low-rotation case, for both species of fields. We produce
plots of these, comparing them to existing exact numerical results with very
good agreement. We also study the total absorption cross-section and
demonstrate that, as in the non-rotating case, it has a different behaviour for
fermions and gauge bosons in the low-energy limit, while it follows a universal
behaviour -- reaching a constant, spin-independent, asymptotic value -- in the
high-energy regime.Comment: 22 pages, 8 figures, added reference
A non-standard matter distribution in the RS1 model and the coupling constant of the radion
In the zero mode approximation we solve exactly the equations of motion for
linearized gravity in the Randall-Sundrum model with a non-standard
distribution of matter in the neighbourhood of the negative tension brane. It
is shown that the form of this distribution can strongly affect the coupling of
the radion to matter. We believe that such a situation can arise in models with
a realistic mechanisms of matter localization.Comment: 12 pages, LaTe
Greybody Factors for Brane Scalar Fields in a Rotating Black-Hole Background
We study the evaporation of (4+n)-dimensional rotating black holes into
scalar degrees of freedom on the brane. We calculate the corresponding
absorption probabilities and cross-sections obtaining analytic solutions in the
low-energy regime, and compare the derived analytic expressions to numerical
results, with very good agreement. We then consider the high-energy regime,
construct an analytic high-energy solution to the scalar-field equation by
employing a new method, and calculate the absorption probability and
cross-section for this energy regime, finding again a very good agreement with
the exact numerical results. We also determine the high-energy asymptotic value
of the total cross-section, and compare it to the analytic results derived from
the application of the geometrical optics limit.Comment: Latex file, 30 pages, 5 figures, typos corrected, version published
in Phys. Rev.
Identification of Ilarviruses in almond and cherry fruit trees using nested PCR assays
In this study nested PCR assays have been developed for the detection of Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV) and Apple mosaic virus (ApMV) modifying a previously reported assay for the generic detection of ilarviruses. In all cases one generic upstream primer was used along with a virus-specific downstream primer in respective nested PCR assays. The application of the same thermocycling profile allowed all amplifications to run in parallel. Ilarvirus isolates from different hosts were used for the evaluation of the detection range of the assays, which were afterwards applied for screening almond and cherry plant material. In almond trees the incidence of PNRSV and PDV was 41% and 21.5%, respectively. In cherry orchards the opposite was observed with PDV (56.6%) being the prevalent virus followed by PNRSV (19.4%). Mixed infections with both viruses were also encountered in approximately 10 and 17% of cherry and almond trees, respectively. ApMV was not detected in any of the samples tested. This is the first extensive survey conducted in Greece in order to monitor the distribution of these viruses using molecular assays. Keywords: Prune dwarf virus, Prunus necrotic ringspot virus, Apple mosaic virus, cherry, almond, nested PC
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