4,532 research outputs found
Magnetic expansion of Nekrasov theory: the SU(2) pure gauge theory
It is recently claimed by Nekrasov and Shatashvili that the
gauge theories in the background with
are related to the quantization of certain algebraic integrable systems. We
study the special case of SU(2) pure gauge theory, the corresponding integrable
model is the A Toda model, which reduces to the sine-Gordon quantum
mechanics problem. The quantum effects can be expressed as the WKB series
written analytically in terms of hypergeometric functions. We obtain the
magnetic and dyonic expansions of the Nekrasov theory by studying the property
of hypergeometric functions in the magnetic and dyonic regions on the moduli
space. We also discuss the relation between the electric-magnetic duality of
gauge theory and the action-action duality of the integrable system.Comment: 17 pages, submitted to PRD; v2, typos corrected, references added;
v3, published versio
KEMNAD: A Knowledge Engineering Methodology for Negotiating Agent Development
Automated negotiation is widely applied in various domains. However, the development of such systems is a complex knowledge and software engineering task. So, a methodology there will be helpful. Unfortunately, none of existing methodologies can offer sufficient, detailed support for such system development. To remove this limitation, this paper develops a new methodology made up of: (1) a generic framework (architectural pattern) for the main task, and (2) a library of modular and reusable design pattern (templates) of subtasks. Thus, it is much easier to build a negotiating agent by assembling these standardised components rather than reinventing the wheel each time. Moreover, since these patterns are identified from a wide variety of existing negotiating agents(especially high impact ones), they can also improve the quality of the final systems developed. In addition, our methodology reveals what types of domain knowledge need to be input into the negotiating agents. This in turn provides a basis for developing techniques to acquire the domain knowledge from human users. This is important because negotiation agents act faithfully on the behalf of their human users and thus the relevant domain knowledge must be acquired from the human users. Finally, our methodology is validated with one high impact system
Coherent X-ray Diffractive Imaging; applications and limitations
The inversion of a diffraction pattern offers aberration-free
diffraction-limited 3D images without the resolution and depth-of-field
limitations of lens-based tomographic systems, the only limitation being
radiation damage. We review our experimental results, discuss the fundamental
limits of this technique and future plans.Comment: 7 pages, 8 figure
X-ray image reconstruction from a diffraction pattern alone
A solution to the inversion problem of scattering would offer aberration-free
diffraction-limited 3D images without the resolution and depth-of-field
limitations of lens-based tomographic systems. Powerful algorithms are
increasingly being used to act as lenses to form such images. Current image
reconstruction methods, however, require the knowledge of the shape of the
object and the low spatial frequencies unavoidably lost in experiments.
Diffractive imaging has thus previously been used to increase the resolution of
images obtained by other means. We demonstrate experimentally here a new
inversion method, which reconstructs the image of the object without the need
for any such prior knowledge.Comment: 5 pages, 3 figures, improved figures and captions, changed titl
Microstructural Characterization of Graphite Spheroids in Ductile Iron
The present work brings new insights by transmission electron microscopy allowing disregarding or supporting some of the models proposed for spheroidal growth of graphite in cast irons. Nodules consist of sectors made of graphite plates elongated along a hai direction and stack on each other with their c axis aligned with the radial direction. These plates are the elementary units for spheroidal growth and a calculation supports the idea that new units continuously nucleate at the ledge between sectors
I=2 Pion scattering length with improved actions on anisotropic lattices
scattering length in the I=2 channel is calculated within quenched
approximation using improved gauge and improved Wilson fermion actions on
anisotropic lattices. The results are extrapolated towards the chiral, infinite
volume and continuum limit. This result improves our previous result on the
scattering length. In the chiral, infinite volume and continuum limit, we
obtain , which is consistent with the result from
Chiral Perturbation Theory, the experiment and results from other lattice
calculations.Comment: 7 pages, 2 figures, typeset wit elsart.cl
DNA cytosine hydroxymethylation levels are distinct among non-overlapping classes of peripheral blood leukocytes
AbstractBackgroundPeripheral blood leukocytes are the most commonly used surrogates to study epigenome-induced risk and epigenomic response to disease-related stress. We considered the hypothesis that the various classes of peripheral leukocytes differentially regulate the synthesis of 5-methylcytosine (5mCG) and its removal via Ten-Eleven Translocation (TET) dioxygenase catalyzed hydroxymethylation to 5-hydroxymethylcytosine (5hmCG), reflecting their responsiveness to environment. Although it is known that reductions in TET1 and/or TET2 activity lead to the over-proliferation of various leukocyte precursors in bone marrow and in development of chronic myelomonocytic leukemia and myeloproliferative neoplasms, the role of 5mCG hydroxymethylation in peripheral blood is less well studied.ResultsWe developed simplified protocols to rapidly and reiteratively isolate non-overlapping leukocyte populations from a single small sample of fresh or frozen whole blood. Among peripheral leukocyte types we found extreme variation in the levels of transcripts encoding proteins involved in cytosine methylation (DNMT1, 3A, 3B), the turnover of 5mC by demethylation (TET1, 2, 3), and DNA repair (GADD45A, B, G) and in the global and gene-region-specific levels of DNA 5hmCG (CD4+ T cellsâ«CD14+ monocytes>CD16+ neutrophils>CD19+ B cells>CD56+ NK cells>Siglec8+ eosinophils>CD8+ T cells).ConclusionsOur data taken together suggest a potential hierarchy of responsiveness among classes of leukocytes with CD4+, CD8+ T cells and CD14+ monocytes being the most distinctly poised for a rapid methylome response to physiological stress and disease
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