7,504 research outputs found
Chiral Sum Rules and Their Phenomenology
We present an analysis of four sum rules, each based on chiral symmetry and
containing the difference of isovector
vector and axialvector spectral functions. Experimental data from tau lepton
decay and electron-positron scattering identify the spectral functions over a
limited kinematic domain. We summarize the status of the existing database.
However, a successful determination of the sum rules requires additional
content, in the form of theoretical input. We show how chiral symmetry and the
operator product expansion can be used to constrain the spectral functions in
the low energy and the high energy limits and proceed to perform a
phenomenological test of the sum rules.Comment: Standard Latex file, 27 pgs (figures not included), UMHEP-38
K -> pi pi Phenomenology in the Presence of Electromagnetism
We describe the influence of electromagnetism on the phenomenology of K -> pi
pi decays. This is required because the present data were analyzed without
inclusion of electromagnetic radiative corrections, and hence contain several
ambiguities and uncertainties which we describe in detail. Our presentation
includes a full description of the infrared effects needed for a new
experimental analysis. It also describes the general treatment of final state
interaction phases, needed because Watson's theorem is no longer valid in the
presence of electromagnetism. The phase of the isospin-two amplitude A_2 may be
modified by 50% -> 100%. We provide a tentative analysis using present data in
order to illustrate the sensitivity to electromagnetic effects, and also
discuss how the standard treatment of epsilon'/epsilon is modified.Comment: 25 pages, 6 figure
The Locus Algorithm III: A Grid Computing system to generate catalogues of optimised pointings for Differential Photometry
This paper discusses the hardware and software components of the Grid
Computing system used to implement the Locus Algorithm to identify optimum
pointings for differential photometry of 61,662,376 stars and 23,799 quasars.
The scale of the data, together with initial operational assessments demanded a
High Performance Computing (HPC) system to complete the data analysis. Grid
computing was chosen as the HPC solution as the optimum choice available within
this project. The physical and logical structure of the National Grid computing
Infrastructure informed the approach that was taken. That approach was one of
layered separation of the different project components to enable maximum
flexibility and extensibility
The Locus Algorithm IV: Performance metrics of a grid computing system used to create catalogues of optimised pointings
This paper discusses the requirements for and performance metrics of the the
Grid Computing system used to implement the Locus Algorithm to identify optimum
pointings for differential photometry of 61,662,376 stars and 23,779 quasars.
Initial operational tests indicated a need for a software system to analyse the
data and a High Performance Computing system to run that software in a scalable
manner. Practical assessments of the performance of the software in a serial
computing environment were used to provide a benchmark against which the
performance metrics of the HPC solution could be compared, as well as to
indicate any bottlenecks in performance. These performance metrics indicated a
distinct split in the performance dictated more by differences in the input
data than by differences in the design of the systems used. This indicates a
need for experimental analysis of system performance, and suggests that
algorithmic complexity analyses may lead to incorrect or naive conclusions,
especially in systems with high data I/O overhead such as grid computing.
Further, it implies that systems which reduce or eliminate this bottleneck such
as in-memory processing could lead to a substantial increase in performance
Gravitational Wave Production At The End Of Inflation
We consider gravitational wave production due to parametric resonance at the
end of inflation, or ``preheating''. This leads to large inhomogeneities which
source a stochastic background of gravitational waves at scales inside the
comoving Hubble horizon at the end of inflation. We confirm that the present
amplitude of these gravitational waves need not depend on the inflationary
energy scale. We analyze an explicit model where the inflationary energy scale
is ~10^9 GeV, yielding a signal close to the sensitivity of Advanced LIGO and
BBO. This signal highlights the possibility of a new observational ``window''
into inflationary physics, and provides significant motivation for searches for
stochastic backgrounds of gravitational waves in the Hz to GHz range, with an
amplitude on the order of \Omega_{gw}(k)h^2 ~ 10^-11. Finally, the strategy
used in our numerical computations is applicable to the gravitational waves
generated by many inhomogeneous processes in the early universe.Comment: 4 pages, Revtex, 2 figures. v2 References added, discussion clarified
and improved. v3 further clarification, typo regarding source corrected.
Basic results unchange
A.B.A. Manual for Conplex Insurance Coverage Litigation: A Prescription for Insurance Nullification
Managing Prolonged Pain After Surgery: Examining the Role of Opioids.
A notable minority of patients experience persistent postsurgical pain and some of these patients consequently have prolonged exposure to opioids. Risk factors for prolonged opioid use after surgery include preoperative opioid use, anxiety, substance abuse, and alcohol abuse. The window to intervene and potentially prevent persistent opioid use after surgery is short and may best be accomplished by both surgeon and anesthesiologist working together. Anesthesiologists in particular are well positioned in the perioperative surgical home model to affect multiple aspects of the perioperative experience, including tailoring intraoperative medications and providing consultation for possible discharge analgesic regimens that can help minimize opioid use. Multimodal analgesia protocols reduce opioid consumption and thereby reduce exposure to opioids and theoretically the risk of persistent use. Regional anesthesia and analgesia techniques also reduce opioid consumption. Although many patients will recover without difficulty, the small minority who do not should receive customized care which may involve multiple office visits or consultation of a pain specialist. Enhanced recovery pathways are useful in optimizing outcomes after surgery
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