351 research outputs found
Differential calculus on the quantum Heisenberg group
The differential calculus on the quantum Heisenberg group is conlinebreak
structed. The duality between quantum Heisenberg group and algebra is proved.Comment: AMSTeX, Pages
Delivering Diagnostic Quality Video over Mobile Wireless Networks for Telemedicine
In real-time remote diagnosis of emergency medical events, mobility can be enabled by wireless video communications. However, clinical use of this potential advance will depend on definitive and compelling demonstrations of the reliability of diagnostic quality video. Because the medical domain has its own fidelity criteria, it is important to incorporate diagnostic video quality criteria into any video compression system design. To this end, we used flexible algorithms for region-of-interest (ROI) video compression and obtained feedback from medical experts to develop criteria for diagnostically lossless (DL) quality. The design of the system occurred in three steps-measurement of bit rate at which DL quality is achieved through evaluation of videos by medical experts, incorporation of that information into a flexible video encoder through the notion of encoder states, and an encoder state update option based on a built-in quality criterion. Medical experts then evaluated our system for the diagnostic quality of the video, allowing us to verify that it is possible to realize DL quality in the ROI at practical communication data transfer rates, enabling mobile medical assessment over bit-rate limited wireless channels. This work lays the scientific foundation for additional validation through prototyped technology, field testing, and clinical trials
Generalized Noiseless Quantum Codes utilizing Quantum Enveloping Algebras
A generalization of the results of Rasetti and Zanardi concerning avoiding
errors in quantum computers by using states preserved by evolution is
presented. The concept of dynamical symmetry is generalized from the level of
classical Lie algebras and groups to the level of dynamical symmetry based on
quantum Lie algebras and quantum groups (in the sense of Woronowicz). A natural
connection is proved between states preserved by representations of a quantum
group and states preserved by evolution with dynamical symmetry of the
appropriate universal enveloping algebra. Illustrative examples are discussed.Comment: 10 pages, LaTeX, 2 figures Postscrip
Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}
Isotope shifts in dielectronic recombination spectra were studied for Li-like
^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance
positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV
(stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j
transitions were deduced. An evaluation of these values within a full QED
treatment yields a change in the mean-square charge radius of ^{142,150}\delta
= -1.36(1)(3) fm^2. The approach is conceptually new and combines the
advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review
Letter
Geometrical (2+1)-gravity and the Chern-Simons formulation: Grafting, Dehn twists, Wilson loop observables and the cosmological constant
We relate the geometrical and the Chern-Simons description of
(2+1)-dimensional gravity for spacetimes of topology , where
is an oriented two-surface of genus , for Lorentzian signature and general
cosmological constant and the Euclidean case with negative cosmological
constant. We show how the variables parametrising the phase space in the
Chern-Simons formalism are obtained from the geometrical description and how
the geometrical construction of (2+1)-spacetimes via grafting along closed,
simple geodesics gives rise to transformations on the phase space. We
demonstrate that these transformations are generated via the Poisson bracket by
one of the two canonical Wilson loop observables associated to the geodesic,
while the other acts as the Hamiltonian for infinitesimal Dehn twists. For
spacetimes with Lorentzian signature, we discuss the role of the cosmological
constant as a deformation parameter in the geometrical and the Chern-Simons
formulation of the theory. In particular, we show that the Lie algebras of the
Chern-Simons gauge groups can be identified with the (2+1)-dimensional Lorentz
algebra over a commutative ring, characterised by a formal parameter
whose square is minus the cosmological constant. In this
framework, the Wilson loop observables that generate grafting and Dehn twists
are obtained as the real and the -component of a Wilson loop
observable with values in the ring, and the grafting transformations can be
viewed as infinitesimal Dehn twists with the parameter .Comment: 50 pages, 6 eps figure
Virtual reality-based parallel coordinates plots enhanced with explainable ai and data-science analytics for decision-making processes
We present a refinement of the Immersive Parallel Coordinates Plots (IPCP) system for Virtual Reality (VR). The evolved system provides data-science analytics built around a well-known method for visualization of multidimensional datasets in VR. The data-science analytics enhancements consist of importance analysis and a number of clustering algorithms including a novel SuMC (Subspace Memory Clustering) solution. These analytical methods were applied to both the main visualizations and supporting cross-dimensional scatter plots. They automate part of the analytical work that in the previous version of IPCP had to be done by an expert. We test the refined system with two sample datasets that represent the optimum solutions of two different multi-objective optimization studies in turbomachinery. The first one describes 54 data items with 29 dimensions (DS1), and the second 166 data items with 39 dimensions (DS2). We include the details of these methods as well as the reasoning behind selecting some methods over others.</jats:p
An advanced tool integrating failure and sensitivity analysis into novel modeling of the stormwater flood volume
An innovative tool for modeling the specific flood volume was
presented that can be applied to assess the need for stormwater network
modernization as well as for advanced flood risk assessment. Field
measurements for a catchment area in Kielce, Poland, were used to apply the
model and demonstrate its usefulness. This model extends the capability of
recently developed statistical and machine learning hydrodynamic models
developed from multiple runs of the US Environmental Protection Agency (EPA) Storm Water Management Model
(SWMM). The extensions enable the inclusion of (1)Â the characteristics of the
catchment and its stormwater network, calibrated model parameters
expressing catchment retention, and the capacity of the sewer system; (2)Â extended sensitivity analysis; and (3)Â risk analysis. Sensitivity
coefficients of calibrated model parameters include correction coefficients
for percentage area, flow path, depth of storage, and impervious area; Manning
roughness coefficients for impervious areas; and Manning roughness
coefficients for sewer channels. Sensitivity coefficients were determined
with respect to rainfall intensity and characteristics of the catchment and
stormwater network. Extended sensitivity analysis enabled an evaluation of
the variability in the specific flood volume and sensitivity coefficients
within a catchment, in order to identify the most vulnerable areas
threatened by flooding. Thus, the model can be used to identify areas
particularly susceptible to stormwater network failure and the sections of
the network where corrective action should be taken to reduce the
probability of system failure. The simulator developed to determine the
specific flood volume represents an alternative approach to the SWMM
that, unlike current approaches, can be calibrated with limited topological
data availability; therefore, the aforementioned simulator incurs a lower cost due to the lower number
and lower specificity of data required.</p
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T-Lymphoblastic Lymphoma Cells Express High Levels of BCL2, S1P1, and ICAM1, Leading to a Blockade of Tumor Cell Intravasation
The molecular events underlying the progression of T-lymphoblastic lymphoma (T-LBL) to acute T-lymphoblastic leukemia (T-ALL) remain elusive. In our zebrafish model, concomitant overexpression of bcl-2 with Myc accelerated T-LBL onset while inhibiting progression to T-ALL. The T-LBL cells failed to invade the vasculature and showed evidence of increased homotypic cell-cell adhesion and autophagy. Further analysis using clinical biopsy specimens revealed autophagy and increased levels of BCL2, S1P1, and ICAM1 in human T-LBL compared with T-ALL. Inhibition of S1P1 signaling in T-LBL cells led to decreased homotypic adhesion in vitro and increased tumor cell intravasation in vivo. Thus, blockade of intravasation and hematologic dissemination in T-LBL is due to elevated S1P1 signaling, increased expression of ICAM1, and augmented homotypic cell-cell adhesion.Stem Cell and Regenerative Biolog
Radiative recombination of bare Bi83+: Experiment versus theory
Electron-ion recombination of completely stripped Bi83+ was investigated at
the Experimental Storage Ring (ESR) of the GSI in Darmstadt. It was the first
experiment of this kind with a bare ion heavier than argon. Absolute
recombination rate coefficients have been measured for relative energies
between ions and electrons from 0 up to about 125 eV. In the energy range from
15 meV to 125 eV a very good agreement is found between the experimental result
and theory for radiative recombination (RR). However, below 15 meV the
experimental rate increasingly exceeds the RR calculation and at Erel = 0 eV it
is a factor of 5.2 above the expected value. For further investigation of this
enhancement phenomenon the electron density in the interaction region was set
to 1.6E6/cm3, 3.2E6/cm3 and 4.7E6/cm3. This variation had no significant
influence on the recombination rate. An additional variation of the magnetic
guiding field of the electrons from 70 mT to 150 mT in steps of 1 mT resulted
in periodic oscillations of the rate which are accompanied by considerable
changes of the transverse electron temperature.Comment: 12 pages, 14 figures, to be published in Phys. Rev. A, see also
http://www.gsi.de/ap/ and http://www.strz.uni-giessen.de/~k
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