460 research outputs found

    Giant palaeo-landslide dammed the Yangtze river

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    Field evidence is presented to demonstrate that a very large landslide blocked the Jinsha River (the main stem of the Yangtze) near the present day town of Qiaojia, Yunnan Province. The discovery is significant because no persistent river-blocking landslide has been reported so far downstream in a major catchment. At the location of the landslide dam the upstream catchment area is 445 × 103 km^2. Sediments deposited behind the dam indicate that the minimum crest height was approximately 200 m with a lake volume of 11.4 +/− 1.3 km^3. The landslide occurred on the western (Sichuan) side of the river and displaced an estimated volume of at least 3.75 km^3, with material riding up to 550 m above the river on the eastern (Yunnan) side of the valley. The location is at the intersection of the Xiaojiang and Zemuhe fault zones which form part of the eastern boundary fault of the Sichuan-Yunnan Fault Block, an area where many earthquakes exceeding magnitude 7.0 have been documented in the historical record

    Transiting Exoplanet Survey Satellite (TESS) Flight Dynamics Commissioning Results and Experiences

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    The Transiting Exoplanet Survey Satellite (TESS) will perform the first-ever spaceborne all-sky exoplanet transit survey and is the first primary-mission application of a lunar-resonant orbit. Launched on April 18, 2018, TESS completed a two-month commissioning phase consisting of three phasing loops followed by a lunar flyby and a final maneuver to achieve resonance. During the mission orbit, no further station-keeping maneuvers are planned or required. NASA Goddard Space Flight Center is performing flight dynamics operations for the mission. This paper covers the design, implementation, and results from TESS commissioning, including the projected performance of the final mission orbit

    t(5;9)(q32;p24) KANK1/PDGFRB

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    Review on t(5;9)(q32;p24) KANK1/PDGFRB, with data on clinics, and the genes involved

    Measurement of residual nucleus cross sections and recoil energies in p + Fe collisions at 300, 500, 750, 1000 and 1500 MeV

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    The production of residual nuclei in p + Fe collisions has been measured at GSI on the FRS facility by means of the reverse kinematic techniques at 300, 500, 750, 1000 and 1500 MeV/A. The cross-sections larger than 0.01 mb of all isotopes with Z larger than 8 have been obtained. Velocity distributions were also measured. Comparisons to models describing spallation reactions and some empirical formulae often used in astrophysics are presented. These data are directly used to calculate impurety production and DPAs in a thin window as foreseen in spallation sources or accelerator-driven systems

    Spallation Residues in the Reaction 56Fe + p at 0.3, 0.5, 0.75, 1.0 and 1.5 A GeV

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    The spallation residues produced in the bombardment of 56}Fe at 1.5, 1.0, 0.75, 0.5 and 0.3 A GeV on a liquid-hydrogen target have been measured using the reverse kinematics technique and the Fragment Separator at GSI (Darmstadt). This technique has permitted the full identification in charge and mass of all isotopes produced with cross-sections larger than 10^{-2} mb down to Z=8. Their individual production cross-sections and recoil velocities at the five energies are presented. Production cross-sections are compared to previously existing data and to empirical parametric formulas, often used in cosmic-ray astrophysics. The experimental data are also extensively compared to different combinations of intra-nuclear cascade and de-excitation models. It is shown that the yields of the lightest isotopes cannot be accounted for by standard evaporation models. The GEMINI model, which includes an asymmetric fission decay mode, gives an overall good agreement with the data. These experimental data can be directly used for the estimation of composition modifications and damages in materials containing iron in spallation sources. They are also useful for improving high precision cosmic-ray measurements.Comment: Submited to Phys. Rev. C (10/2006

    Effect of priming with granulocyte colony-stimulating factor on the outcome of chemotherapy for acute myeloid leukemia

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    BACKGROUND: Sensitization of leukemic cells with hematopoietic growth factors may enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML). METHODS: In a multicenter randomized trial, we assigned patients (age range, 18 to 60 years) with newly diagnosed AML to receive cytarabine plus idarubicin (cycle 1) and cytarabine plus amsacrin (cycle 2) with granulocyte colony-stimulating factor (G-CSF) (321 patients) or without G-CSF (319). G-CSF was given concurrently with chemotherapy only. Idarubicin and amsacrin were given at the end of a cycle to allow the cell-cycle-dependent cytotoxicity of cytarabine in the context of G-CSF to have a greater effect. The effect of G-CSF on disease-free survival was assessed in all patients and in cytogenetically distinct prognostic subgroups. RESULTS: After induction chemotherapy, the rates of response were not significantly different in the two groups. After a median follow-up of 55 months, patients in complete remission after induction chemotherapy plus G-CSF had a higher rate of disease-free survival than patients who did not receive G-CSF (42 percent vs. 33 percent at four years, P=0.02), owing to a reduced probability of relapse (relative risk, 0.77; 95 percent confidence interval, 0.61 to 0.99; P=0.04). G-CSF did not significantly improve overall survival (P=0.16). Although G-CSF did not improve the outcome in the subgroup with an unfavorable prognosis, the 72 percent of patients with standard-risk AML benefited from G-CSF therapy (overall survival at four years, 45 percent, as compared with 35 percent in the group that did not receive G-CSF [relative risk of death, 0.75; 95 percent confidence interval, 0.59 to 0.95; P=0.02]; disease-free survival, 45 percent vs. 33 percent [relative risk, 0.70]; 95 percent confidence interval, 0.55 to 0.90; P=0.006). CONCLUSIONS: Sensitization of leukemic cells with growth factors is a clinically applicable means of enhancing the efficacy of chemotherapy in patients with AML

    Transiting Exoplanet Survey Satellite (TESS) Flight Dynamics Commissioning Results and Experiences

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    The Transiting Exoplanet Survey Satellite (TESS) will perform the first-ever spaceborne all-sky exoplanet transit survey and is the first primary-mission application of a lunar-resonant orbit. Launched on April 18, 2018, TESS completed a two-month commissioning phase consisting of three phasing loops followed by a lunar flyby and a final maneuver to achieve resonance. During the mission orbit, no further station-keeping maneuvers are planned or required. NASA Goddard Space Flight Center is performing flight dynamics operations for the mission. This paper covers the design, implementation, and results from TESS commissioning, including the projected performance of the final mission orbit

    New measurement of neutron capture resonances of 209Bi

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    The neutron capture cross section of Bi209 has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of gamma-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. Gamma-ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because Bi209 is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha-decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At this low temperature an important part of the heavy Pb-Bi isotopes are supposed to be synthesized by the s-process in the He shells of low mass, thermally pulsing asymptotic giant branch stars. With the improved set of cross sections we obtain an s-process fraction of 19(3)% of the solar bismuth abundance, resulting in an r-process residual of 81(3)%. The present (n,gamma) cross-section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.Comment: 10 pages, 5figures, recently published in Phys. Rev.

    Measurement of the neutron capture cross section of the s-only isotope 204Pb from 1 eV to 440 keV

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    The neutron capture cross section of 204Pb has been measured at the CERN n_TOF installation with high resolution in the energy range from 1 eV to 440 keV. An R-matrix analysis of the resolved resonance region, between 1 eV and 100 keV, was carried out using the SAMMY code. In the interval between 100 keV and 440 keV we report the average capture cross section. The background in the entire neutron energy range could be reliably determined from the measurement of a 208Pb sample. Other systematic effects in this measurement could be investigated and precisely corrected by means of detailed Monte Carlo simulations. We obtain a Maxwellian average capture cross section for 204Pb at kT=30 keV of 79(3) mb, in agreement with previous experiments. However our cross section at kT=5 keV is about 35% larger than the values reported so far. The implications of the new cross section for the s-process abundance contributions in the Pb/Bi region are discussed.Comment: 8 pages, 3 figures, article submitted to Phys. Rev.
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