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[en] The ZEUS detector at the DESY e-p collider HERA has started collecting data. It contains a state-of-the-art fully compensating high resolution Uranium-scintillator calorimeter. The American part of the ZEUS collaboration was responsible for the construction of the 32 modules of the Barrel CALorimeter (BCAL) and the readout electronics for the complete calorimeter. A test beam experiment E790 was set up in a fixed-target beamline at Fermilab to test and calibrate the BCAL modules to 1%. The analysis of the test beam data with different incident beams at different energies showed a 1% tower-to-tower uniformity, studied the inter-module and inter-tower responses, and measured a hadron resolution of 35%/√E(E in GeV), an electromagnetic resolution of 19%/√E. It also demonstrated the equality of the electromagnetic and the hadronic responses and the linearity of the responses of the calorimeter and the readout electronics. The Mark III collaboration has measured the J/ψ leptonic branching fractions using the process ψ (3685) → π+π-J/ψ,J/ψ → l+l-. The results are: B(J/ψ → e+e-) = (5.92 ± 0.15 ± 0.20)% and B(J/ψ → μ+μ-) = (5.90 ± 0.15 ± 0.19)%, where the first error is statistical and the second is systematic. Assuming lepton universality, the leptonic branching fraction of the J/ψ is (5.91 ± 0.11 ± 0.20)%. This result is used to obtain the strong coupling constant αs and the QCD scale factor ΛMS
[en] SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source. One of the possibilities is a new PEP-X 4.5 GeV storage ring that would be housed in the 2.2 km PEP-II tunnel. The PEP-X is designed to produce photon beams having brightness near 1022 (ph/s/mm2/mrad2/0.1% BW) at 10 keV with 3.5 m undulator at beam current of 1.5 A. This report presents an overview of the PEP-X baseline lattice design and describes the lattice optimization procedures in order to maximize the beam dynamic aperture. The complete report of PEP-X baseline design is published in SLAC report.
[en] A lattice for the PEP-X ultimate storage ring light source, having 11 pm-rad natural emittance at a beam energy of 4.5 GeV at zero current, using 90 m of damping wiggler and fitting into the existing 2.2-km PEP-II tunnel, has been recently designed. Such a low emittance lattice requires very strong sextupoles for chromaticity correction, which in turn introduce strong non-linear field effects that limit the beam dynamic aperture. In order to maximize the dynamic aperture we choose the cell phases to cancel the third and fourth order geometric resonances in each 8-cell arc. Four families of chromatic sextupoles and six families of geometric (or harmonic) sextupoles are added to correct the chromatic and amplitude-dependent tunes. To find the best settings of the ten sextupole families, we use a Multi-Objective Genetic Optimizer employing elegant to optimize the beam lifetime and dynamic aperture simultaneously. Then we evaluate dynamic aperture reduction caused by magnetic field multipole errors, magnet fabrication errors and misalignments. A sufficient dynamic aperture is obtained for injection, as well as workable beam lifetime.
[en] SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source. Storage ring design is one of the possibilities that would be housed in the 2.2-km PEP-II tunnel. The design goal of PEPX storage ring is to approach an optimal light source design with horizontal emittance less than 100 pm and vertical emittance of 8 pm to reach the diffraction limit of 1-(angstrom) x-ray. The low emittance design requires a lattice with strong focusing leading to high natural chromaticity and therefore to strong sextupoles. The latter caused reduction of dynamic aperture. The dynamic aperture requirement for horizontal injection at injection point is about 10 mm. In order to achieve the desired dynamic aperture the transverse non-linearity of PEP-X is studied. The program LEGO is used to simulate the particle motion. The technique of frequency map is used to analyze the nonlinear behavior. The effect of the non-linearity is tried to minimize at the given constrains of limited space. The details and results of dynamic aperture optimization are discussed in this paper.
[en] Highlights: • Two loop analysis to deal with uncertainties in the structural integrity assessment of steam generator tubing. • The comparison between deterministic assessment and probabilistic assessment with varying confidence levels. • Two acceptance standards for the probabilistic structural integrity assessment. - Abstract: A probabilistic structural integrity assessment framework utilizing a two-loop Monte Carlo simulation process is proposed. The process and interpretation of the results are demonstrated using an example of Steam Generator (SG) tubing with fretting flaws. Acceptance standards established using a 95/90/90 criterion (which represents 95% probability at 90th percentile with 90% one-sided confidence) is proposed and compared with the generally accepted deterministic and traditional probabilistic acceptance standards
[en] Microarray data analyses were performed to search for metastasis-associated oncogenes in prostate cancer (PCa). RNF31 mRNA expressions in tumor tissues and benign prostate tissues were evaluated. The RNF31 protein expression levels were also analyzed by western blot and immunohistochemistry. Luciferase reporter assays were used to identify miRNAs that can regulate RNF31. The effect of RNF31 on PCa progression was studied in vitro and in vivo. We found that RNF31 was significantly increased in PCa and its expression level was highly correlated with seminal vesicle invasion, clinical stage, prostate specific antigen (PSA) level, Gleason score, and BCR. Silence of RNF31 suppressed PCa cell proliferation and metastasis in vitro and in vivo. miR-503 can directly regulate RNF31. Enforced expression of miR-503 inhibited the expression of RNF31 significantly and the restoration of RNF31 expression reversed the inhibitory effects of miR-503 on PCa cell proliferation and metastasis. These findings collectively indicated an oncogene role of RNF31 in PCa progression which can be regulated by miR-503, suggesting that RNF31 could serve as a potential prognostic biomarker and therapeutic target for PCa. - Highlights: • RNF31 is a potential metastasis associated gene and is associated with prostate cancer progression. • Silence of RNF31 inhibits PCa cell colony formation, migration and invasion. • RNF31 as a direct target of miR-503. • miR-503 can regulate cell proliferation, invasion and migration by targeting RNF31. • RNF31 plays an important role in PCa growth and metastasis in vivo
[en] Heat-treatment and machining are two key process when manufacturing pressurizer forging, which need to be performed heat-treatment many times to assure its mechanical strength because of being used as the pressure-resistant vessel. The mechanical property of forging must be satisfied the technology requirements after preliminary heat-treatment and property heat-treatment. Because the enclosure heat of Qinshan phase-II nuclear power project is a special big type spherical surface, it is very difficult to perform its mechanical machining. The author introduces a mechanical machining method to overcome the difficulty for hoisting and determining datum
[en] The virtual cathode oscillation in relativistic electron beams is studied by a 1-D electrostatic particle simulation code with finite-size-particle model. When injection current is less than the space charge limiting current, electron beam propagates stably and transsmits completely. When injection current exceeds the space charge limit, its propagation is unstable, a part of electrons reflect and the other electrons transsmit. The position and potential of the virtual cathode caused by space charge effects oscillate periodically. When the beam current increases, the virtual cathode position closer to the injection plane and its oscillating region gets narrower, the virtual cathode potential decreases and its amplitude increases, the oscillation frequency increases above the beam plasma frequency