83 research outputs found

    Solvable Discrete Quantum Mechanics: q-Orthogonal Polynomials with |q|=1 and Quantum Dilogarithm

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    Several kinds of q-orthogonal polynomials with |q|=1 are constructed as the main parts of the eigenfunctions of new solvable discrete quantum mechanical systems. Their orthogonality weight functions consist of quantum dilogarithm functions, which are a natural extension of the Euler gamma functions and the q-gamma functions (q-shifted factorials). The dimensions of the orthogonal spaces are finite. These q-orthogonal polynomials are expressed in terms of the Askey-Wilson polynomials and their certain limit forms.Comment: 37 pages. Comments and references added. To appear in J.Math.Phy

    Extensive genomic diversity and selective conservation of virulence determinants in enterohemorrhagic Escherichia coli strains of O157 and non O157 serotypes

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    Background: Enterohemorrhagic Escherichia coli (EHEC) O157 causes severe food-borne illness in humans. The chromosome of O157 consists of 4.1 Mb backbone sequences shared by benign E. coli K-12, and 1.4 Mb O157-specific sequences encoding many virulence determinants, such as Shiga toxin genes (stx genes) and the locus of enterocyte effacement (LEE). Non-O157 EHECs belonging to distinct clonal lineages from O157 also cause similar illness in humans. According to the "parallel" evolution model, they have independently acquired the major virulence determinants, the stx genes and LEE. However, the genomic differences between O157 and non-O157 EHECs have not yet been systematically analyzed. Results: Using microarray and whole genome PCR scanning analyses, we performed a whole genome comparison of 20 EHEC strains of O26, O111, and O103 serotypes with O157. In non-O157 EHEC strains, although genome sizes were similar with or rather larger than O157 and the backbone regions were well conserved, O157-specific regions were very poorly conserved. Around only 20% of the O157- specific genes were fully conserved in each non-O157 serotype. However, the non-O157 EHECs contained a significant number of virulence genes that are found on prophages and plasmids in O157, and also multiple prophages similar to, but significantly divergent from, those in O157. Conclusion: Although O157 and non-O157 EHECs have independently acquired a huge amount of serotype- or strain-specific genes by lateral gene transfer, they share an unexpectedly large number of virulence genes. Independent infections of similar but distinct bacteriophages carrying these virulence determinants are deeply involved in the evolution of O157 and non-O157 EHECs

    Analysis of Synthetic Cylindrical Array Beam-Forming in Presence of the Elements Position-Error for Semi-Anechoic Chamber Evaluation

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    Abstract-This paper describes the study of synthetic cylindrical array beam-forming for narrowband signals, under the influence of antenna elements position-error. The required side-lobe level and the physical dimensions of the array are presumed based on the requirements and limitations to evaluate a RF semi-anechoic chamber. Dolph-Chebyshev algorithm is used for beam-forming because of its optimal beam-width for a predefined uniform sidelobe level. Monte-Carlo simulations reveal the sensitivity of the beam-pattern side-lobe level to the elements position-error

    Cross sections for nuclide production in proton- and deuteron-induced reactions on 93

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    Isotopic production cross sections were measured for proton- and deuteron-induced reactions on 93Nb by means of the inverse kinematics method at RIKEN Radioactive Isotope Beam Factory. The measured production cross sections of residual nuclei in the reaction 93Nb + p at 113 MeV/u were compared with previous data measured by the conventional activation method in the proton energy range between 46 and 249 MeV. The present inverse kinematics data of four reaction products (90Mo, 90Nb, 88Y, and 86Y) were in good agreement with the data of activation measurement. Also, the model calculations with PHITS describing the intra-nuclear cascade and evaporation processes generally well reproduced the measured isotopic production cross sections

    Near-Field Antenna Measurements Using Photonic Sensor of Mach-Zehnder Interferometer

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    We have been developing a photonic sensor system to measure the electric near-field distribution at a distance shorter than one wavelength from the aperture of an antenna. The photonic sensor is a type of Mach-Zehnder interferometer and consists of an array antenna of 2.4 mm height and 2 mm width on a LiNbO3 substrate (0.5 mm thickness, 8 mm length, and 3 mm width) supported by a glass pipe. The photonic sensor can be considered to be a receiving infinitesimal dipole antenna that is a tiny metallic part printed on a small dielectric plate at microwave frequency. Those physical and electrical features make the photonic sensor attractive when used as a probe for near-field antenna measurements. We have demonstrated that the system can be applied to planar, spherical, and cylindrical near-field antenna measurements without any probe compensation approximately below 10 GHz. We show the theories and the measurements using the photonic sensor in the three near-field antenna measurement methods

    Usefulness of novel fusion imaging with zero TE sequence and contrast-enhanced T1WI for cavernous sinus dural arteriovenous fistula

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    Evaluation of access routes and shunting points plays a crucial role in the treatment of cavernous sinus dural arteriovenous fistulas (CS-dAVF). Generally, these evaluations are performed using three-dimensional rotation angiography. However, assessing access routes becomes challenging in cases lacking anterior or posterior drainage routes. Zero TE magnetic resonance imaging (MRI) is an innovative technique enabling the visualization of cortical bone. By merging fusion images of zero TE and contrast-enhanced T1 weighted imaging (CE-T1WI), enhanced arteries can be visualized, resembling cranial bone-like three-dimensional rotation angiography. To determine the usefulness of fusion images in evaluating access routes and shunting points for dural arteriovenous fistulas, a comparison was made between these fusion images and three-dimensional rotation angiography in the same case. This report describes the application of fusion images in evaluating access routes and shunting points
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