415 research outputs found
Reconstruction of SU(5) Grand Unified Model In Noncommutative Geometry Approach
Based on the generalized gauge theory on , we
reconstructed the realistic SU(5) Grand Unified model by a suitable assignment
of fermion fields. The action of group elements on fermion fields is the
charge conjugation while the action of elements represent generation
translation. We find that to fit the spontaneous symmetry breaking and gauge
hierarchy of SU(5) model a linear term of curvature has to be introduced. A new
mass relation is obtained in our reconstructed model.Comment: 16 pages, Late
Lithotripter Shockwave-Induced Enhancement of Mouse Melanoma Lung Metastasis: Dependence on Cavitation Nucleation
Purpose: To confirm a previous report of metastasis enhancement by lithotripter shockwaves (LSW) and to test the hypothesis that this effect is attributable to cavitation. Materials and Methods: The metastatic B16-D5 melanoma cell line was implanted on the hind legs of female C57/b16 mice 12 days before tumor treatment. The tumors were treated with 500 LSW in a waterbath arrangement. The effect of augmented cavitation nucleation was tested by intratumor injection of air bubbles or ultrasound contrast agent gas bodies (UCAGB). The primary tumor was surgically removed on day 1 after treatment. The six groups of mice were sham, LSW, sham + air bubbles, LSW + air bubbles, sham + UCAGB, and LSW + UCAGB. Data were collected for the 113 mice that survived at least 25 days. Lung evaluations were performed blind after 2 weeks of bleaching in Fekete's solution. Results: The outcomes of the three sham groups were very similar and indicated that the simple injection of material into the tumor did not increase metastasis. In comparison with the pooled shams, both the LSW + air bubbles and LSW + UCAGB groups had statistically significant increases in metastasis counts. Only the LSW + UCAGB group had a significant increase in incidence of metastasis relative to the pooled shams. The LSW + UCAGB also had significantly reduced survival. Conclusion: Shockwaves can enhance metastasis from tumors, and this effect is attributable to cavitation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63207/1/end.2004.18.925.pd
Multi-frame image restoration method for novel rotating synthetic aperture imaging system
Abstract The novel rotating synthetic aperture (RSA) optical imaging system is an important development direction for future high-resolution optical remote sensing satellites in geostationary orbit. However, owing to the rotating rectangular pupil, the point spread function of the RSA system has an asymmetric spatial distribution, and the images obtained using the primary mirror from different rotation angles have nonuniform blur degradation. Moreover, platform vibration and pupil rotation have coupling effects on the RSA imaging, resulting in further radiometric and geometric quality degradation. To address these problems, the image degradation characteristics are first analyzed according to the imaging mechanism. Then, combined with the theory of mutual information, an image registration method is suggested by introducing the orientation gradient information. From this, a multi-frame image restoration model is proposed based on the directional gradient prior of the RSA system image. From the perspective of interpretation and application, when the aspect ratio is less than 3, the proposed inversion restoration method can achieve a satisfactory processing performance. This work can provide engineering application reference for the future space application of RSA imaging technology
Novel Schemes for Directly Measuring Entanglement of General States
An intrinsic relation between maximally entangled states and entanglement
measures is revealed, which plays a role in establishing connections for
different entanglement quantifiers. We exploit the basic idea and propose a
framework to construct schemes for directly measuring entanglement of general
states. In particular, we demonstrate that rank-1 local factorizable projective
measurements, which are achievable with only one copy of entangled state
involved at a time in a sequential way, are sufficient to directly determine
the concurrence of arbitrary two-qubit entangled state
Microwave photo-association of fine-structure-induced Rydberg macro-dimer molecules of cesium
Long-range Rydberg macro-dimers are observed in an
ultracold cesium Rydberg gas for . Strong dipolar "flip"
(,
) and
"cross" () couplings lead to bound, fine-structure-mixed
macro-dimers at energies between the fine-structure levels. The
macro-dimers are measured by microwave photo-association from optically
prepared Rydberg pair states. Calculated adiabatic potential
curves are used to elucidate the underlying physics and to model the
macro-dimer spectra, with good overall agreement. Microwave photo-association
allows Franck-Condon tuning, which we have studied by varying the detuning of a
Rydberg-atom excitation laser. Further, in Stark spectroscopy we have measured
molecular DC electric polarizabilities that are considerably larger than those
of the atomic states. The large molecular polarizabilities may be caused by
high- mixing. The observed linewidths of the Stark-shifted molecular
lines provide initial evidence for intra-molecular induced-dipole-dipole
interaction
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