398 research outputs found
On the screening of static electromagnetic fields in hot QED plasmas
We study the screening of static magnetic and electric fields in massless
quantum electrodynamics (QED) and massless scalar electrodynamics (SQED) at
temperature . Various exact relations for the static polarisation tensor are
first reviewed and then verified perturbatively to fifth order (in the
coupling) in QED and fourth order in SQED, using different resummation
techniques. The magnetic and electric screening masses squared, as defined
through the pole of the static propagators, are also calculated to fifth order
in QED and fourth order in SQED, and their gauge-independence and
renormalisation-group invariance is checked. Finally, we provide arguments for
the vanishing of the magnetic mass to all orders in perturbation theory.Comment: 37 pages, 8 figure
Quarkonium Suppression
I discuss quarkonium suppression in equilibriated strongly interacting
matter. After a brief review of basic features of quarkonium production I
discuss the application of recent lattice data on the heavy quark potential to
the problem of quarkonium dissociation as well as the problem of direct lattice
determination of quarkonium properties in finite temperature lattice QCD.Comment: Invited plenary talk presented on 4th International Conference on
Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP-2001), November
26-30, 2001, Jaipur; 12 pp, LaTeX, uses pramana.st
Non-perturbative Debye mass in finite T QCD
Employing a non-perturbative gauge invariant definition of the Debye
screening mass m_D in the effective field theory approach to finite T QCD, we
use 3d lattice simulations to determine the leading O(g^2) and to estimate the
next-to-leading O(g^3) corrections to m_D in the high temperature region. The
O(g^2) correction is large and modifies qualitatively the standard
power-counting hierarchy picture of correlation lengths in high temperature
QCD.Comment: 4 pages, Late
Two flavor chiral phase transition from nonperturbative flow equations
We employ nonperturbative flow equations to compute the equation of state for
two flavor QCD within an effective quark meson model. This yields the
temperature and quark mass dependence of quantities like the chiral condensate
or the pion mass. A precision estimate of the universal critical equation of
state for the three-dimensional O(4) Heisenberg model is presented. We
explicitly connect the O(4) universal behavior near the critical temperature
and zero quark mass with the physics at zero temperature and a realistic pion
mass. For realistic quark masses the pion correlation length near T_c turns out
to be smaller than its zero temperature value.Comment: 49 pages including 15 figures, LaTeX, uses epsf.sty and rotate.st
ALFRED: an allele frequency resource for research and teaching
ALFRED (http://alfred.med.yale.edu) is a free, web accessible, curated compilation of allele frequency data on DNA sequence polymorphisms in anthropologically defined human populations. Currently, ALFRED has allele frequency tables on over 663â400 polymorphic sites; 170 of them have frequency tables for more than 100 different population samples. In ALFRED, a population may have multiple samples with each âsampleâ consisting of many individuals on which an allele frequency is based. There are 3566 population samples from 710 different populations with allele frequency tables on at least one polymorphism. Fifty of those population samples have allele frequency data for over 650â000 polymorphisms. Records also have active links to relevant resources (dbSNP, PharmGKB, OMIM, Ethnologue, etc.). The flexible search options and data display and download capabilities available through the web interface allow easy access to the large quantity of high-quality data in ALFRED
Heavy Quark Potentials in Quenched QCD at High Temperature
Heavy quark potentials are investigated at high temperatures. The temperature
range covered by the analysis extends from values just below the
deconfinement temperature up to about in the deconfined phase. We
simulated the pure gauge sector of QCD on lattices with temporal extents of 4,
6 and 8 with spatial volumes of . On the smallest lattice a tree level
improved action was employed while in the other two cases the standard Wilson
action was used. Below we find a temperature dependent logarithmic term
contributing to the confinement potential and observe a string tension which
decreases with rising temperature but retains a finite value at the
deconfinement transition. Above the potential is Debye-screened, however
simple perturbative predictions do not apply.Comment: 20 pages, 9 figure
Occupational therapy department's engagement in the organizational management of coronavirus disease-2019 pandemic in an acute care setup: Perspective from a clinical and administrative experience and a narrative review
Background: Coronavirus disease-2019 (COVID-19) pandemic came as a big challenge to the medical fraternity. The novelty of its manifestation
made it clear that occupational therapy (OT) professionals would require to adapt to the ever-changing scenario of the pandemic and engage in
newer roles to combat the pandemic. Objective: The objective of the study was to provide descriptive narration of the process of engagement
of the OT department in handling the COVID-19 pandemic at an acute care setup. Study Design: A perspective from a clinical experience
and a narrative review. Methods: Narrative account of the initiatives, challenges, preparations, and outcomes of the measures taken by the
King Edward VII Memorial Hospitalâs (KEMH) OT Departmentâs professionals as part of a multidisciplinary team member in combating
the COVID-19 pandemic is reported. The occupational therapist at KEMH used core OT principles and teachings in treatment sessions and
managerial functions to aid patients and the organization during the pandemic. Results: The measures taken by the OT department professionals
at KEMH helped facilitate the management of the COVID-19 pandemic at the hospital. Being well-versed with the organizationâs style of
functioning and philosophy enabled the OT department to work as part of a multidisciplinary team. The active participation of occupational
therapists underlined their role in acute respiratory conditions. It helped OT be a part of the critical management of COVID-19 patients admitted
in the hospital and at the Jumbo care centers developed by the hospital team of experts. Conclusion: The COVID-19 pandemic allowed OT
professionals to create new processes and enhance service delivery through innovative actions in an acute care setup
Lifetimes of quasiparticles and collective excitations in hot QED plasmas
The perturbative calculation of the lifetime of fermion excitations in a QED
plasma at high temperature is plagued with infrared divergences which are not
eliminated by the screening corrections. The physical processes responsible for
these divergences are the collisions involving the exchange of longwavelength,
quasistatic, magnetic photons, which are not screened by plasma effects. The
leading divergences can be resummed in a non-perturbative treatement based on a
generalization of the Bloch-Nordsieck model at finite temperature. The
resulting expression of the fermion propagator is free of infrared problems,
and exhibits a {\it non-exponential} damping at large times: , where is the plasma
frequency and .Comment: LaTex file, 57 pages, 11 eps figures include
The dilemma of arranged marriages in people with epilepsy. An expert group appraisal
INTRODUCTION: Matrimony remains a challenging psychosocial problem confronting people with epilepsy (PWE). People with epilepsy are less likely to marry; however, their marital prospects are most seriously compromised in arranged marriages.
AIMS: The aim of this study was to document marital prospects and outcomes in PWE going through arranged marriage and to propose optimal practices for counseling PWE contemplating arranged marriage.
METHODS: A MEDLINE search and literature review were conducted, followed by a cross-disciplinary meeting of experts to generate consensus.
RESULTS: People with epilepsy experience high levels of felt and enacted stigma in arranged marriages, but the repercussions are heavily biased against women. Hiding epilepsy is common during marital negotiations but may be associated with poor medication adherence, reduced physician visits, and poor marital outcome. Although divorce rates are generally insubstantial in PWE, divorce rates appear to be higher in PWE undergoing arranged marriages. In these marriages, hiding epilepsy during marital negotiations is a risk factor for divorce.
CONCLUSIONS: In communities in which arranged marriages are common, physicians caring for PWE are best-equipped to counsel them about their marital prospects. Marital plans and aspirations should be discussed with the family of the person with epilepsy in a timely and proactive manner. The benefits of disclosing epilepsy during marital negotiations should be underscored
The Quark Gluon Plasma: lattice computations put to experimental test
I describe how lattice computations are being used to extract experimentally
relevant features of the quark gluon plasma. I deal specifically with
relaxation times, photon emissivity, strangeness yields, event by event
fluctuations of conserved quantities and hydrodynamic flow. Finally I give
evidence that the plasma is liquid-like in some ways.Comment: Review talk at the QCD02 meeting, IIT Kanpur, Indi
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