2,199 research outputs found
Gauge Dressing of 2D Field Theories
By using the gauge Ward identities, we study correlation functions of gauged
WZNW models. We show that the gauge dressing of the correlation functions can
be taken into account as a solution of the Knizhnik-Zamolodchikov equation. Our
method is analogous to the analysis of the gravitational dressing of 2D field
theories.Comment: 13 pages, Late
A review of Emma Wilby’s The Visions of Isobel Gowdie: Magic, Witchcraft and Dark Shamanism in Seventeenth-Century Scotland (Sussex University Press, 2010)
<div>This is an annotated data management plan (DMP) template for an Engineering and Physical Sciences Research Council (EPSRC) data management plan.<br></div><div><br></div><div>This document (available in .pdf and .docx formats) was created using the <a href="https://dmponline.dcc.ac.uk/">DMPonline tool</a>, which provides templates for structuring major research funders' DMPs. The document includes the guidance text provided in the tool, produced by the <a href="http://www.dcc.ac.uk/sites/default/files/documents/publications/DMP-themes.pdf">Digital Curation Centre (DCC)</a>, the <a href="https://www.epsrc.ac.uk/about/standards/researchdata/expectations/">EPSRC</a> and the <a href="https://www.sheffield.ac.uk/library/rdm/dmp">University of Sheffield Library</a>. </div><div><br></div><div>Although the EPSRC does not require that a DMP is submitted as part of a grant application, it still expects one to be in place. A DMP describes how you will collect, organise, manage, store, secure, backup, preserve, and where applicable, share your data. The EPSRC DMP template is organised into seven sections and the resulting DMP is expected to be two or three of pages of A4 in length. </div><div><br></div><div>For further guidance see the <a href="https://www.epsrc.ac.uk/about/standards/researchdata/expectations/">EPSRC expectations concerning management of research data</a> and the DCC webpages on <a href="http://www.dcc.ac.uk/resources/data-management-plans">Data management Plans</a> and <a href="http://www.dcc.ac.uk/resources/how-guides/develop-data-plan">How to Develop a Data Management and Sharing Plan</a>. </div
Knizhnik-Zamolodchikov-type equations for gauged WZNW models
We study correlation functions of coset constructions by utilizing the method
of gauge dressing. As an example we apply this method to the minimal models and
to the Witten 2D black hole. We exhibit a striking similarity between the
latter and the gravitational dressing. In particular, we look for logarithmic
operators in the 2D black hole.Comment: 24 pages, latex, no figures. More discussion of logarithmic operators
was adde
Role of aminotransferases in glutamate metabolism of human erythrocytes
Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from α-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional 1H–13C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis
State-space models' dirty little secrets: even simple linear Gaussian models can have estimation problems
State-space models (SSMs) are increasingly used in ecology to model
time-series such as animal movement paths and population dynamics. This type of
hierarchical model is often structured to account for two levels of
variability: biological stochasticity and measurement error. SSMs are flexible.
They can model linear and nonlinear processes using a variety of statistical
distributions. Recent ecological SSMs are often complex, with a large number of
parameters to estimate. Through a simulation study, we show that even simple
linear Gaussian SSMs can suffer from parameter- and state-estimation problems.
We demonstrate that these problems occur primarily when measurement error is
larger than biological stochasticity, the condition that often drives
ecologists to use SSMs. Using an animal movement example, we show how these
estimation problems can affect ecological inference. Biased parameter estimates
of a SSM describing the movement of polar bears (\textit{Ursus maritimus})
result in overestimating their energy expenditure. We suggest potential
solutions, but show that it often remains difficult to estimate parameters.
While SSMs are powerful tools, they can give misleading results and we urge
ecologists to assess whether the parameters can be estimated accurately before
drawing ecological conclusions from their results
Cyanobacteria and microalgae in supporting human habitation on Mars
Establishing the first human presence on Mars will be the most technically challenging undertaking yet in the exploration beyond our planet. The remoteness of Mars from Earth, the inhospitable surface conditions including low atmospheric pressure and cold temperatures, and the need for basic resources including water, pose a formidable challenge to this endeavour. The intersection of multiple disciplines will be required to provide solutions for temporary and eventually permanent Martian habitation. This review considers the role cyanobacteria and eukaryotic microalgae (collectively referred to here as ‘microalgae’) may have in supporting missions to the red planet. The current research using these microorganisms in biological life support systems is discussed, with a systematic analysis of their usage in each system conducted. The potential of microalgae to provide astronauts with oxygen, food, bio-polymers and pharmaceuticals is considered. An overview of microalgal experiments in space missions across the last 60 years is presented, and the research exploring the technical challenges of cultivation on Mars is discussed. From these findings, an argument for culturing microalgae in subterranean bioreactors is proposed. Finally, future synthetic biology approaches for enhancing the cyanobacterial/microalgal role in supporting human deep-space exploration are presented. We show that microalgae hold significant promise for providing solutions to many problems faced by the first Martian settlers, however these can only be realised with significant infrastructure and a reliable power source
Constraints on the Atmospheric Circulation and Variability of the Eccentric Hot Jupiter XO-3b
We report secondary eclipse photometry of the hot Jupiter XO-3b in the
4.5~m band taken with the Infrared Array Camera (IRAC) on the Spitzer
Space Telescope. We measure individual eclipse depths and center of eclipse
times for a total of twelve secondary eclipses. We fit these data
simultaneously with two transits observed in the same band in order to obtain a
global best-fit secondary eclipse depth of and a center of
eclipse phase of . We assess the relative magnitude of
variations in the dayside brightness of the planet by measuring the size of the
residuals during ingress and egress from fitting the combined eclipse light
curve with a uniform disk model and place an upper limit of 0.05. The new
secondary eclipse observations extend the total baseline from one and a half
years to nearly three years, allowing us to place an upper limit on the
periastron precession rate of degrees/day the tightest
constraint to date on the periastron precession rate of a hot Jupiter. We use
the new transit observations to calculate improved estimates for the system
properties, including an updated orbital ephemeris. We also use the large
number of secondary eclipses to obtain the most stringent limits to date on the
orbit-to-orbit variability of an eccentric hot Jupiter and demonstrate the
consistency of multiple-epoch Spitzer observations.Comment: 14 pages, 11 figures, published by Ap
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