932 research outputs found

    Electroproduction of the d* dibaryon

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    The unpolarized cross section for the electroproduction of the isoscalar Jπ=3+J^\pi = 3^+ di-delta dibaryon dd^* is calculated for deuteron target using a simple picture of elastic electron-baryon scattering from the ΔΔ(7D1)\Delta \Delta (^7D_1) and the NN(3S1)NN (^3S_1) components of the deuteron. The calculated differential cross section at the electron lab energy of 1 GeV has the value of about 0.24 (0.05) nb/sr at the lab angle of 10^\circ (30^\circ) for the Bonn B potential when the dibaryon mass is taken to be 2.1 GeV. The cross section decreases rapidly with increasing dibaryon mass. A large calculated width of 40 MeV for d(ΔΔ7S3)d^*(\Delta\Delta ^7S_3) combined with a small experimental upper bound of 0.08 MeV for the dd^* decay width appears to have excluded any low-mass dd^* model containing a significant admixture of the ΔΔ(7S3)\Delta\Delta (^7S_3) configuration.Comment: 11 journal-style pages, 8 figure

    The Role of Finite Element Analysis in Studying Potential Failure of Mandibular Reconstruction Methods

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    Defects of the mandible occur after trauma or resection after infection or tumours. There have been many methods espoused, but many methods can fail especially if the biomechanics of the mandible is not considered fully. As the only moveable, load-bearing bone of the skull, the mandible is subject to loads and stresses unique to it due to its shape, location and function. This chapter reviews the basic knowledge of the mandible necessary to perform finite element analysis, the challenges and then reviews several studies that have been done. The authors’ personal research is detailed to illustrate how finite element analysis can be used to look at potential failure of a new method for mandibular reconstruction and implant evaluation

    Finite Density Algorithm in Lattice QCD -- a Canonical Ensemble Approach

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    I will review the finite density algorithm for lattice QCD based on finite chemical potential and summarize the associated difficulties. I will propose a canonical ensemble approach which projects out the finite baryon number sector from the fermion determinant. For this algorithm to work, it requires an efficient method for calculating the fermion determinant and a Monte Carlo algorithm which accommodates unbiased estimate of the probability. I shall report on the progress made along this direction with the Pad\'{e} - Z2_2 estimator of the determinant and its implementation in the newly developed Noisy Monte Carlo algorithm.Comment: Invited talk at Nankai Symposium on Mathematical Physics, Tianjin, Oct. 2001, 18 pages, 3 figures; expanded and references adde

    Review of the initial validation and characterization of a chicken 3K SNP array.

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    In 2004 the chicken genome sequence and more than 2.8 million single nucleotide polymorphisms (SNPs) were reported. This information greatly enhanced the ability of poultry scientists to understand chicken biology, especially with respect to identification of quantitative trait loci (QTL) and genes that control simple and complex traits. To validate and address the quality of the reported SNPs, assays for 3072 SNPS were developed and used to genotype 2576 DNAs isolated from commercial and experimental birds. Over 90% of the SNPs were valid based on the criterion used for segregating, and over 88% had a minor allele frequency of 2% or greater. As the East Lansing (EL) and Wageningen University (WAU) reference panels were genotyped, 1933 SNPs were added to the chicken genetic map, which was used in the second chicken genome sequence assembly. It was also discovered that linkage disequilibrium varied considerably between commercial layers and broilers; with the latter having haplotype blocks averaging 10 to 50 kb in size. Finally, it was estimated that commercial lines have lost 70% or more of their genetic diversity, with the majority of allele loss attributable to the limited number of chicken breeds used

    Observations of temporal group delays in slow-light multiple coupled photonic crystal cavities

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    We demonstrate temporal group delays in coherently-coupled high-Q multi-cavity photonic crystals, in an all-optical analogue to electromagnetically induced transparency. We report deterministic control of the group delay up to 4× the single cavity lifetime in our CMOS-fabricated room-temperature chip. Supported by three-dimensional numerical simulations and theoretical analyses, our multi-pump beam approach enables control of the multi-cavity resonances and inter-cavity phase, in both single and double transparency peaks. The standing-wave wavelength-scale photon localization allows direct scalability for chip-scale optical pulse trapping and coupled-cavity QED

    Elevated Perioperative Transaminase Level Predicts Intrahepatic Recurrence in Hepatitis B-related Hepatocellular Carcinoma After Curative Hepatectomy

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    OBJECTIVEWe aimed to evaluate the role of elevated perioperative alanine aminotransferase (ALT) as a surrogate marker of hepatitis activity in determining the risk of recurrence and survival in hepatitis B-related hepatocellular carcinoma (HCC) after curative hepatectomy.METHODSA retrospective review of the hepatectomy database was performed and 142 patients were found who had hepatitis B-related HCC from January 2001 to March 2006. Their ALT levels preoperatively and 1 month, 3 months, and 6 months postoperatively were recorded. The risk factors for recurrence and prognostic factors of survival were analysed.RESULTSAn elevated perioperative ALT level (p = 0.021), multiple tumour nodules in the resected specimen (p < 0.001), and a tumour size greater than 5 cm (p = 0.001) were significant independent risk factors for tumour recurrence. The latter two factors were also independent prognostic factors for overall survival and disease-free survival. An elevated ALT level was an independent prognostic factor for disease-free survival (p = 0.025).CONCLUSIONAn elevated perioperative ALT level, which reflects increased hepatitis activity, is an independent risk factor for intrahepatic recurrence of hepatitis B-related HCC. It is also associated with a poorer disease-free survival rate

    A Multiobjective Spatial-based Zone Design Model (MoSZoD)

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    This paper presents a multiobjective approach for a spatial-based zone design model to the division of a land surface into two or more pieces. The model employs multiobjective optimization technique and Geographic Information System (GIS) as its components. This paper defines the problem based on multiobjective because it considers relationship among objectives and it is much more realistic to solve a real-world spatial zoning problem. The multiobjective decision analysis has been used to approximate and handle the Pareto-optimal solution to get optimal solution set after this paper applies a heuristic method to generate nondominated alternatives. This paper also aggregates the decision-makers' preferences by allowing interactivity with decision-makers. The flow of the model and its implementation in the GIS environment is presented. The computation has resulted in improvements in spatial zoning

    Adiabatic elimination in quantum stochastic models

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    We consider a physical system with a coupling to bosonic reservoirs via a quantum stochastic differential equation. We study the limit of this model as the coupling strength tends to infinity. We show that in this limit the solution to the quantum stochastic differential equation converges strongly to the solution of a limit quantum stochastic differential equation. In the limiting dynamics the excited states are removed and the ground states couple directly to the reservoirs.Comment: 17 pages, no figures, corrected mistake
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