533 research outputs found
Comparison of Boltzmann Kinetics with Quantum Dynamics for a Chiral Yukawa Model Far From Equilibrium
Boltzmann equations are often used to describe the non-equilibrium
time-evolution of many-body systems in particle physics. Prominent examples are
the computation of the baryon asymmetry of the universe and the evolution of
the quark-gluon plasma after a relativistic heavy ion collision. However,
Boltzmann equations are only a classical approximation of the quantum
thermalization process, which is described by so-called Kadanoff-Baym
equations. This raises the question how reliable Boltzmann equations are as
approximations to the complete Kadanoff-Baym equations. Therefore, we present
in this article a detailed comparison of Boltzmann and Kadanoff-Baym equations
in the framework of a chirally invariant Yukawa-type quantum field theory
including fermions and scalars. The obtained numerical results reveal
significant differences between both types of equations. Apart from
quantitative differences, on a qualitative level the late-time universality
respected by Kadanoff-Baym equations is severely restricted in the case of
Boltzmann equations. Furthermore, Kadanoff-Baym equations strongly separate the
time scales between kinetic and chemical equilibration. In contrast to this
standard Boltzmann equations cannot describe the process of quantum-chemical
equilibration, and consequently also cannot feature the above separation of
time scales.Comment: 17 pages, 8 figures, REVTeX
Palmitoleic acid prevents palmitic acid-induced macrophage activation and consequent p38 MAPK-mediated-skeletal muscle insulin resistance
Obesity and saturated fatty acid (SFA) treatment are both associated with skeletal muscle insulin resistance (IR) and increased macrophage infiltration. However, the relative effects of SFA and unsaturated fatty acid (UFA)-activated macrophages on muscle are unknown. Here, macrophages were treated with palmitic acid, palmitoleic acid or both and the effects of the conditioned medium (CM) on C2C12 myotubes investigated. CM from palmitic acid-treated J774s (palm-mac-CM) impaired insulin signalling and insulin-stimulated glycogen synthesis, reduced Inhibitor κBα and increased phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase in myotubes. p38 MAPK inhibition or siRNA partially ameliorated these defects, as did addition of tumour necrosis factor-α blocking antibody to the CM. Macrophages incubated with both FAs generated CM that did not induce IR, while palmitoleic acid-mac-CM alone was insulin sensitising. Thus UFAs may improve muscle insulin sensitivity and counteract SFA-mediated IR through an effect on macrophage activation
Polly’s story : using structural narrative analysis to understand a trans migration journey
There is scant theoretical and empirical research on experiences of trans and its significance for social work practice. In this paper we premise that research on trans identity and practice needs to be located in particular temporal, cultural, spatial/geographical contexts and argue that a structural narrative analytical approach centring on plot, offers the opportunity to unravel the ‘how’ and ‘why’ stories are told. We posit that attending to narrative structure facilitates a deeper understanding of trans people’s situated, lived experiences than thematic narrative analysis alone, since people organise their narratives according to a culturally available repertoire including plots. The paper focuses on the life and narrative of Polly, a male-to-female trans woman, and her gender migration journey using the plot typology ‘the Quest’. We are cognisant of the limitations to structural narrative analysis and Western conventions of storytelling, and acknowledge that our approach is subjective; however, we argue that knowledge itself is contextual and perspective ridden, shaped by researchers and participants. Our position holds that narratives are not – and cannot – be separated from the context in which they are told, and importantly the resources used to tell them, and that analysing narrative structure can contextualise individual unique biographies and give voice to less heard communities
Quantum nonlocality and applications in quantum-information processing of hybrid entangled states
The hybrid entangled states generated, e.g., in a trapped-ion or atom-cavity
system, have exactly one ebit of entanglement, but are not maximally entangled.
We demonstrate this by showing that they violate, but in general do not
maximally violate, Bell's inequality due to Clauser, Horne, Shimony and Holt.
These states are interesting in that they exhibit the entanglement between two
distinct degrees of freedom (one is discrete and another is continuous). We
then demonstrate these entangled states as a valuable resource in quantum
information processing including quantum teleportation, entanglement swapping
and quantum computation with "parity qubits". Our work establishes an
interesting link between quantum information protocols of discrete and
continuous variables.Comment: 5 pages, no figur
Survival in Living Kidney Donors: An Australian and New Zealand Cohort Study Using Data Linkage
Background. Living kidney donors are a highly selected healthy population expected to have high survival postdonation, but mortality studies are limited. Our study aimed to compare mortality in living kidney donors with the general population in Australia and New Zealand, hypothesizing that donor survival would exceed average survival. Methods. All living kidney donors in Australia, 2004–2013, and New Zealand, 2004–2012, from the Australian and New Zealand Living Kidney Donor Registry were included. We ascertained primary cause of death from data linkage with national death registers. Standardized mortality ratios and relative survival were estimated, matching on age, sex, calendar year, and country. Results. Among 3253 living kidney donors, there were 32 deaths over 20331 person-years, with median follow-up 6.2 years [interquartile range: 3.9–8.4]. Only 25 donors had diabetes-fasting blood sugar level predonation, of which 3 had impaired glucose toler- ance. At discharge, the median creatinine was 108 μmol/L and estimated glomerular filtration rate was 58 mL/min/1.72 m2. Four deaths occurred in the first year: 2 from immediate complications of donation, and 2 from unrelated accidental causes. The leading cause of death was cancer (n = 16). The crude mortality rate was 157 (95% confidence interval [CI], 111- 222)/100000 person-y, and the standardized mortality ratio was 0.33 (95% CI, 0.24-0.47). The 5-year cumulative relative survival was 1.019 (95% CI, 1.014-1.021), confirming that the survival probability in living kidney donors was 2% higher rela- tive to the general population. Conclusions. As expected, mortality in living kidney donors was substantially lower than the general population and is reassuring for potential donor counseling. The Living Donor Registry only captured a third of the deaths, highlighting the benefit of data linkage to national death registries in the long-term follow-up of living kidney donors.This study received financial support from Kidney Health Australia (2015
Quantum Color Transparency and Nuclear Filtering
Color transparency is the proposal that under certain circumstances the
strong interactions can be reduced in magnitude. We give a comprehensive review
of the physics, which hinges on the interface of perturbative QCD with
non--perturbative strong interactions. Color transparency is complementary to
{\it nuclear filtering}, which is the conversion of quark wave functions in
hadrons to small transverse space dimensions by interaction with a nuclear
medium. We review current approaches, including pictures based on modeling the
time evolution of hadronic wave--packets as well as the use of light cone
matrix elements. Spin plays an intrinsic role in testing and understanding the
physics and is discussed at length. We emphasize the use of data analysis
procedures which have minimal model dependence. We also review existing
experimental data and the experimental program planned at various facilities.
The subject has strong scientific complementarity and potential to make
progress in exploring hadron physics at current and future facilities.Comment: 131 pages, review article in LaTeX to appear in Physics Reports, no
postscipt figures, approximately 30 figures available from Ralston on reques
Clinical disorders affecting mesopic vision
Vision in the mesopic range is affected by a number of inherited and acquired clinical disorders. We review these conditions and summarize the historical background, describing the clinical characteristics alongside the genetic basis and molecular biological mechanisms giving rise to rod and cone dysfunction relevant to twilight vision. The current diagnostic gold standards for each disease are discussed and curative and symptomatic treatment strategies are summarized
25-Hydroxyvitamin D levels and chronic kidney disease in the AusDiab (Australian Diabetes, Obesity and Lifestyle) study
<p>Abstract</p> <p>Background</p> <p>Low 25-hydroxy vitamin D (25(OH)D) levels have been associated with an increased risk of albuminuria, however an association with glomerular filtration rate (GFR) is not clear. We explored the relationship between 25(OH)D levels and prevalent chronic kidney disease (CKD), albuminuria and impaired GFR, in a national, population-based cohort of Australian adults (AusDiab Study).</p> <p>Methods</p> <p>10,732 adults ≥25 years of age participating in the baseline survey of the AusDiab study (1999–2000) were included. The GFR was estimated using an enzymatic creatinine assay and the CKD-EPI equation, with CKD defined as eGFR <60 ml/min/1.73 m<sup>2</sup>. Albuminuria was defined as a spot urine albumin to creatinine ratio (ACR) of ≥2.5 mg/mmol for men and ≥3.5 for women. Serum 25(OH)D levels of <50 nmol/L were considered vitamin D deficient. The associations between 25(OH)D level, albuminuria and impaired eGFR were estimated using multivariate regression models.</p> <p>Results</p> <p>30.7% of the study population had a 25(OH)D level <50 nmol/L (95% CI 25.6-35.8). 25(OH)D deficiency was significantly associated with an impaired eGFR in the univariate model (OR 1.52, 95% CI 1.07-2.17), but not in the multivariate model (OR 0.95, 95% CI 0.67-1.35). 25(OH)D deficiency was significantly associated with albuminuria in the univariate (OR 2.05, 95% CI 1.58-2.67) and multivariate models (OR 1.54, 95% CI 1.14-2.07).</p> <p>Conclusions</p> <p>Vitamin D deficiency is common in this population, and 25(OH)D levels of <50 nmol/L were independently associated with albuminuria, but not with impaired eGFR. These associations warrant further exploration in prospective and interventional studies.</p
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