6 research outputs found
Improved numerical stability of stationary black hole evolution calculations
We experiment with modifications of the BSSN form of the Einstein field
equations (a reformulation of the ADM equations) and demonstrate how these
modifications affect the stability of numerical black hole evolution
calculations. We use excision to evolve both non-rotating and rotating
Kerr-Schild black holes in octant and equatorial symmetry, and without any
symmetry assumptions, and obtain accurate and stable simulations for specific
angular momenta J/M of up to about 0.9M.Comment: 13 pages, 11 figures, 1 typo in Eq. (20) correcte
Occurrence of Euchaeta paraconcinna Fleminger, 1957 (Crustacea, Copepoda, Calanoida) in a coastal area of Bahia State, northeastern Brazil
A comunidade microfitoplanctônica do Arquipélago de São Pedro e São Paulo (Atlântico Norte-Equatorial): variação diurna e espacial
Source profiling of arsenic and heavy metals in the Selangor River basin and their maternal and cord blood levels in Selangor State, Malaysia
Arsenic and 5 heavy metals (nickel, copper, zinc, cadmium and lead) were quantitated in surface water (n = 18) and soil/ore samples (n = 45) collected from 5 land uses (oil palm converted from forest, oil palm in peat swamp, bare land, quarry and forest) in the Selangor River basin by inductively coupled plasma mass spectrometry (ICP-MS). Geographic information system (GIS) was used as a spatial analytical tool to classify 4 land uses (forest, agriculture/peat, urban and bare land) from a satellite image taken by Landsat 8. Source profiling of the 6 elements was conducted to identify their occurrence, their distribution and the pollution source associated with the land use. The concentrations of arsenic, cadmium and lead were also analyzed in maternal blood (n = 99) and cord blood (n = 87) specimens from 136 pregnant women collected at the University of Malaya Medical Center for elucidating maternal exposure as well as maternal-to-fetal transfer. The source profiling identified that nickel and zinc were discharged from sewage and/or industrial effluents, and that lead was discharged from mining sites. Arsenic showed a site-specific pollution in tin-tungsten deposit areas, and the pollution source could be associated with arsenopyrite. The maternal blood levels of arsenic (0.82 ± 0.61 μg/dL), cadmium (0.15 ± 0.2 μg/dL) and lead (2.6 ± 2.1 μg/dL) were not significantly high compared to their acute toxicity levels, but could have attributable risks of chronic toxicity. Those in cord blood were significantly decreased in cadmium (0.06 ± 0.07 μg/dL) and lead (0.99 ± 1.2 μg/dL) but were equivalent in arsenic (0.82 ± 1.1 μg/dL) because of the different kinetics of maternal-to-fetal transfer
Onset of collectivity for argon isotopes close to <math><mrow><mi>N</mi><mo>=</mo><mn>32</mn></mrow></math>
International audienceThe shell closure at N=32 has been investigated by a first spectroscopy of the N=31 nucleus Ar49 at the Radioactive Isotope Beam Factory. Using the Ar50(p,pn) reaction channel in inverse kinematics, Ar50 projectiles at 217 MeV/nucleon impinged on a 150 mm long liquid hydrogen target, part of the MINOS device. Prompt deexcitation γ rays were measured with the NaI(Tl) array DALI2+. Reaction products were analyzed with the SAMURAI spectrometer, which allowed the measurement of the momentum distributions and angular momentum transfer. Data were compared to state-of-the-art theoretical predictions, including shell-model, energy-density functional, and ab initio calculations. An onset of collectivity is suggested besides the spherical configuration typical of a closed shell nucleus, such as for Ca52