1,957 research outputs found
Three-loop HTL gluon thermodynamics at intermediate coupling
We calculate the thermodynamic functions of pure-glue QCD to three-loop order
using the hard-thermal-loop perturbation theory (HTLpt) reorganization of
finite temperature quantum field theory. We show that at three-loop order
hard-thermal-loop perturbation theory is compatible with lattice results for
the pressure, energy density, and entropy down to temperatures .
Our results suggest that HTLpt provides a systematic framework that can used to
calculate static and dynamic quantities for temperatures relevant at LHC.Comment: 24 pages, 13 figs. 2nd version: improved discussion and fixing typos.
Published in JHE
Three-loop HTL QCD thermodynamics
The hard-thermal-loop perturbation theory (HTLpt) framework is used to
calculate the thermodynamic functions of a quark-gluon plasma to three-loop
order. This is the highest order accessible by finite temperature perturbation
theory applied to a non-Abelian gauge theory before the high-temperature
infrared catastrophe. All ultraviolet divergences are eliminated by
renormalization of the vacuum, the HTL mass parameters, and the strong coupling
constant. After choosing a prescription for the mass parameters, the three-loop
results for the pressure and trace anomaly are found to be in very good
agreement with recent lattice data down to , which are
temperatures accessible by current and forthcoming heavy-ion collision
experiments.Comment: 27 pages, 11 figures; corresponds with published version in JHE
Prevalence and anatomical location of muscle tenderness in adults with nonspecific neck/shoulder pain
<p>Abstract</p> <p>Background</p> <p>Many adults experience bothersome neck/shoulder pain. While research and treatment strategies often focus on the upper trapezius, other neck/shoulder muscles may be affected as well. The aim of the present study is to evaluate the prevalence and anatomical location of muscle tenderness in adults with nonspecific neck/shoulder pain.</p> <p>Methods</p> <p>Clinical neck/shoulder examination at two large office workplaces in Copenhagen, Denmark. 174 women and 24 men (aged 25-65 years) with nonspecific neck/shoulder pain for a duration of at least 30 days during the previous year and a pain intensity of at least 2 on a modified VAS-scale of 0-10 participated. Exclusion criteria were traumatic injuries or other serious chronic disease. Using a standardized finger pressure of 2 kg, palpable tenderness were performed of eight anatomical neck/shoulder locations in the left and right side on a scale of 'no tenderness', 'some tenderness' and 'severe tenderness'.</p> <p>Results</p> <p>In women, the levator scapulae, neck extensors and infraspinatus showed the highest prevalence of severe tenderness (18-30%). In comparison, the prevalence of severe tenderness in the upper trapezius, occipital border and supraspinatus was 13-19%. Severe tenderness of the medial deltoid was least prevalent (0-1%). In men, the prevalence of severe tenderness in the levator scapulae was 13-21%, and ranged between 0-8% in the remainder of the examined anatomical locations.</p> <p>Conclusions</p> <p>A high prevalence of tenderness exists in several anatomical locations of the neck/shoulder complex among adults with nonspecific neck/shoulder pain. Future research should focus on several neck/shoulder muscles, including the levator scapulae, neck extensors and infraspinatus, and not only the upper trapezius.</p> <p>Trial Registration</p> <p><a href="http://www.controlled-trials.com/ISRCTN60264809">ISRCTN60264809</a></p
Resummation scheme for 3d Yang-Mills and the two-loop magnetic mass for hot gauge theories
Perturbation theory for non-Abelian gauge theories at finite temperature is
plagued by infrared divergences caused by magnetic soft modes ,
which correspond to the fields of a 3d Yang-Mills theory. We revisit a gauge
invariant resummation scheme to solve this problem by self-consistent mass
generation using an auxiliary scalar field, improving over previous attempts in
two respects. First, we generalise earlier SU(2) treatments to SU(N). Second,
we obtain a gauge independent two-loop gap equation, correcting an error in the
literature. The resulting two-loop approximation to the magnetic mass
represents a correction to the leading one-loop value, indicating a
reasonable convergence of the resummation.Comment: 16 pages, 3 figure
Care, laboratory beagles and affective utopia
A caring approach to knowledge production has been portrayed as epistemologically radical, ethically vital and as fostering continuous responsibility between researchers and research-subjects. This article examines these arguments through focusing on the ambivalent role of care within the first large-scale experimental beagle colony, a self-professed ‘beagle utopia’ at the University of California, Davis, (1951-1986). We argue that care was at the core of the beagle colony; the lived environment was re-shaped in response to animals ‘speaking back’ to researchers, and ‘love’ and ‘kindness’ were important considerations during staff recruitment. Ultimately, however, we show that care-relations were used to manufacture compliancy, preventing the predetermined ends of the experiment from being troubled. Rather than suggesting Davis would have been less ethically troubling, or more epistemologically radical, with ‘better’ care, however, we suggest the case troubles existing care theory and argue that greater attention needs to be paid to histories, contexts, and exclusions
New absolute magnitude calibrations for detached binaries
Lutz-Kelker bias corrected absolute magnitude calibrations for the detached
binary systems with main-sequence components are presented. The absolute
magnitudes of the calibrator stars were derived at intrinsic colours of
Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As
for the calibrator stars, 44 detached binaries were selected from the Hipparcos
catalogue, which have relative observed parallax errors smaller than 15%
(). The calibration equations which provide the
corrected absolute magnitude for optical and near-infrared pass bands are valid
for wide ranges of colours and absolute magnitudes: ,
and , ,
, respectively. The distances computed using the luminosity-colours
(LCs) relation with optical (BV) and near-infrared () observations
were compared to the distances found from various other methods. The results
show that new absolute magnitude calibrations of this study can be used as a
convenient statistical tool to estimate the true distances of detached binaries
out of Hipparcos' distance limit.Comment: 10 pages, 4 figures and 5 tables, accepted for publication in
Astronomische Nachrichte
Does computer use pose a hazard for future long-term sickness absence?
The aim of the study was to investigate if weekly duration of computer use predicted sickness absence for more than two weeks at a later time
Population Selection and Sequencing of Caenorhabditis elegans Wild Isolates Identifies a Region on Chromosome III Affecting Starvation Resistance
To understand the genetic basis of complex traits, it is important to be able to efficiently
phenotype many genetically distinct individuals. In the nematode Caenorhabditis elegans, individuals have
been isolated from diverse populations around the globe and whole-genome sequenced. As a result,
hundreds of wild strains with known genome sequences can be used for genome-wide association studies
(GWAS). However, phenotypic analysis of these strains can be laborious, particularly for quantitative traits
requiring multiple measurements per strain. Starvation resistance is likely a fitness-proximal trait for nematodes, and it is related to metabolic disease risk in humans. However, natural variation in C. elegans
starvation resistance has not been systematically characterized, and precise measurement of the trait is
time-intensive. Here, we developed a population-selection-and-sequencing-based approach to phenotype
starvation resistance in a pool of 96 wild strains. We used restriction site-associated DNA sequencing
(RAD-seq) to infer the frequency of each strain among survivors in a mixed culture over time during
starvation. We used manual starvation survival assays to validate the trait data, confirming that strains that
increased in frequency over time are starvation-resistant relative to strains that decreased in frequency.
Further, we found that variation in starvation resistance is significantly associated with variation at a region
on chromosome III. Using a near-isogenic line (NIL), we showed the importance of this genomic interval for
starvation resistance. This study demonstrates the feasibility of using population selection and sequencing
in an animal model for phenotypic analysis of quantitative traits, documents natural variation of starvation
resistance in C. elegans, and identifies a genomic region that contributes to such variation
Experimental entanglement distillation of mesoscopic quantum states
The distribution of entangled states between distant parties in an optical
network is crucial for the successful implementation of various quantum
communication protocols such as quantum cryptography, teleportation and dense
coding [1-3]. However, owing to the unavoidable loss in any real optical
channel, the distribution of loss-intolerant entangled states is inevitably
inflicted by decoherence, which causes a degradation of the transmitted
entanglement. To combat the decoherence, entanglement distillation, which is
the process of extracting a small set of highly entangled states from a large
set of less entangled states, can be used [4-14]. Here we report on the
mesoscopic distillation of deterministically prepared entangled light pulses
that have undergone non-Gaussian noise. The entangled light pulses [15-17] are
sent through a lossy channel, where the transmission is varying in time
similarly to light propagation in the atmosphere. By employing linear optical
components and global classical communication, the entanglement is
probabilistically increased.Comment: 13 pages, 4 figures. It's the first submitted version to the Nature
Physics. The final version is already published on Nature Physics vol.4,
No.12, 919 - 923 (2008
Etiological Profile and Treatment Outcome of Epistaxis at a Tertiary Care Hospital in Northwestern Tanzania: A Prospective Review of 104 Cases.
Epistaxis is the commonest otolaryngological emergency affecting up to 60% of the population in their lifetime, with 6% requiring medical attention. There is paucity of published data regarding the management of epistaxis in Tanzania, especially the study area. This study was conducted to describe the etiological profile and treatment outcome of epistaxis at Bugando Medical Centre, a tertiary care hospital in Northwestern Tanzania. This was a prospective descriptive study of the cases of epistaxis managed at Bugando Medical Centre from January 2008 to December 2010. Data collected were analyzed using SPSS computer software version 15. A total of 104 patients with epistaxis were studied. Males were affected twice more than the females (2.7:1). Their mean age was 32.24 ± 12.54 years (range 4 to 82 years). The modal age group was 31-40 years. The commonest cause of epistaxis was trauma (30.8%) followed by idiopathic (26.9%) and hypertension (17.3%). Anterior nasal bleeding was noted in majority of the patients (88.7%). Non surgical measures such as observation alone (40.4%) and anterior nasal packing (38.5%) were the main intervention methods in 98.1% of cases. Surgical measures mainly intranasal tumor resection was carried out in 1.9% of cases. Arterial ligation and endovascular embolization were not performed. Complication rate was 3.8%. The overall mean of hospital stay was 7.2 ± 1.6 days (range 1 to 24 days). Five patients died giving a mortality rate of 4.8%. Trauma resulting from road traffic crush (RTC) remains the most common etiological factor for epistaxis in our setting. Most cases were successfully managed with conservative (non-surgical) treatment alone and surgical intervention with its potential complications may not be necessary in most cases and should be the last resort. Reducing the incidence of trauma from RTC will reduce the incidence of emergency epistaxis in our centre
- …