53 research outputs found
3D Gamma-ray and Neutron Mapping in Real-Time with the Localization and Mapping Platform from Unmanned Aerial Systems and Man-Portable Configurations
Nuclear Scene Data Fusion (SDF), implemented in the Localization and Mapping
Platform (LAMP) fuses three-dimensional (3D), real-time volumetric
reconstructions of radiation sources with contextual information (e.g. LIDAR,
camera, etc.) derived from the environment around the detector system. This
information, particularly when obtained in real time, may be transformative for
applications, including directed search for lost or stolen sources, consequence
management after the release of radioactive materials, or contamination
avoidance in security-related or emergency response scenarios. 3D
reconstructions enabled by SDF localize contamination or hotspots to specific
areas or objects, providing higher resolution over larger areas than
conventional 2D approaches, and enabling more efficient planning and response,
particularly in complex 3D environments.
In this work, we present the expansion of these gamma-ray mapping concepts to
neutron source localization. Here we integrate LAMP with a custom
(CLLBC) scintillator detector sensitive to both
gamma-rays and neutrons, which we dub Neutron Gamma LAMP (NG-LAMP). NG-LAMP
enables simultaneous neutron and gamma-ray mapping with high resolution
gamma-ray spectroscopy. We demonstrate the ability to detect and localize
surrogate Special Nuclear Materials (SNM) in real-time and in 3D based on
neutron signatures alone, which is critical for the detection of heavily
shielded SNM, when gamma-ray signatures are attenuated. In this work, we show
for the first time the ability to localize, in 3D and realtime, a neutron
source in the presence of a strong gamma-ray source, simultaneous and
spectroscopic localization of three gamma-ray sources and a neutron source, and
finally the localization of a surrogate SNM source based on neutron signatures
alone, where gamma-ray data are consistent with background
Affine sl(N) conformal blocks from N=2 SU(N) gauge theories
Recently Alday and Tachikawa proposed a relation between conformal blocks in
a two-dimensional theory with affine sl(2) symmetry and instanton partition
functions in four-dimensional conformal N=2 SU(2) quiver gauge theories in the
presence of a certain surface operator. In this paper we extend this proposal
to a relation between conformal blocks in theories with affine sl(N) symmetry
and instanton partition functions in conformal N=2 SU(N) quiver gauge theories
in the presence of a surface operator. We also discuss the extension to
non-conformal N=2 SU(N) theories.Comment: 40 pages. v2: minor changes and clarification
A quantum isomonodromy equation and its application to N=2 SU(N) gauge theories
We give an explicit differential equation which is expected to determine the
instanton partition function in the presence of the full surface operator in
N=2 SU(N) gauge theory. The differential equation arises as a quantization of a
certain Hamiltonian system of isomonodromy type discovered by Fuji, Suzuki and
Tsuda.Comment: 15 pages, v2: typos corrected and references added, v3: discussion,
appendix and references adde
Instanton partition functions in N=2 SU(N) gauge theories with a general surface operator, and their W-algebra duals
We write down an explicit conjecture for the instanton partition functions in
4d N=2 SU(N) gauge theories in the presence of a certain type of surface
operator. These surface operators are classified by partitions of N, and for
each partition there is an associated partition function. For the partition N=N
we recover the Nekrasov formalism, and when N=1+...+1 we reproduce the result
of Feigin et. al. For the case N=1+(N-1) our expression is consistent with an
alternative formulation in terms of a restricted SU(N)xSU(N) instanton
partition function. When N=1+...+1+2 the partition functions can also be
obtained perturbatively from certain W-algebras known as quasi-superconformal
algebras, in agreement with a recent general proposal.Comment: 20 page
Geometric Representation Theory and Gauge Theory
This book offers a review of the vibrant areas of geometric representation theory and gauge theory, which are characterized by a merging of traditional techniques in representation theory with the use of powerful tools from algebraic geometry, and with strong inputs from physics. The notes are based on lectures delivered at the CIME school "Geometric Representation Theory and Gauge Theory" held in Cetraro, Italy, in June 2018. They comprise three contributions, due to Alexander Braverman and Michael Finkelberg, Andrei Negut, and Alexei Oblomkov, respectively. Braverman and Finkelberg\u2019s notes review the mathematical theory of the Coulomb branch of 3D N=4 quantum gauge theories. The purpose of Negut\u2019s notes is to study moduli spaces of sheaves on a surface, as well as Hecke correspondences between them. Oblomkov's notes concern matrix factorizations and knot homology. This book will appeal to both mathematicians and theoretical physicists and will be a source of inspiration for PhD students and researchers
Detection of coronary artery disease in asymptomatic patients with type 2 diabetes mellitus
We sought to verify the effectiveness of current American Diabetes Association screening guidelines in identifying asymptomatic patients with coronary artery disease (CAD) in type 2 diabetes mellitus (DM2).
BACKGROUND In DM2 patients, CAD generally is detected in an advanced stage with an extensive atherosclerosis and poor outcome, whereas CAD in an asymptomatic stage is commonly
missed.
METHODS This study included 1,899 asymptomatic DM2 patients (age >60 years). Of these, 1,121 had >2 associated risk factors (RFs), group A, and the remaining 778 had >1 RF, group B, for
CAD. All patients underwent dipyridamole myocardial contrast echocardiography (MCE), and in those with myocardial perfusion defects, the anatomy of coronary vessels was analyzed
by selective coronary angiography.
RESULTS In the two study groups, the prevalence of abnormal MCE (59.4% vs. 60%, p < 0.96) and
of a significant CAD (64.6% vs. 65.5%, p <0.92) was similar, irrespective of RF profile. But coronary anatomy differed: group B had a lower prevalence of three-vessel disease (7.6% vs.
33.3%, p <0.001), of diffuse disease (18.0% vs. 54.9%, p 0.001), and of vessel occlusion (3.8% vs. 31.2%, p <0.001), whereas one-vessel disease was more frequent (70.6% vs. 46.3%, p < 0.001). Coronary anatomy did not allow any revascularization procedure in 45% of group A patients.
CONCLUSIONS An \u201caggressive\u201d diagnostic approach, requiring coronary angiography in asymptomatic DM2 patients with >1 associated RF for CAD and abnormal MCE, identified patients with a subclinical CAD characterized by a more favorable angiographic anatomy. The criterion of >2 RFs did not help to identify asymptomatic patients with a higher prevalence of CAD and is only related to a more severe CAD with unfavorable coronary anatomy
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