Efficacy of the SU(3) scheme for ab initio large-scale calculations beyond the lightest nuclei

We report on the computational characteristics of ab initio nuclear structure calculations in a symmetry-adapted no-core shell model (SA-NCSM) framework. We examine the computational complexity of the current implementation of the SA-NCSM approach, dubbed LSU3shell, by analyzing ab initio results for 6Li and 12C in large harmonic oscillator model spaces and SU(3)-selected subspaces. We demonstrate LSU3shell's strong-scaling properties achieved with highly-parallel methods for computing the many-body matrix elements. Results compare favorably with complete model space calculations and significant memory savings are achieved in physically important applications. In particular, a well-chosen symmetry-adapted basis affords memory savings in calculations of states with a fixed total angular momentum in large model spaces while exactly preserving translational invariance.Comment: 11 pages, 8 figure

Collective Modes in Light Nuclei from First Principles

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.Comment: 5 pages 3 figures, accepted to Physical Review Letter

Morphological Changes in the Hepatic Tissue at the Impact of Industrial Copper-bearing Dust in the Experiment

BACKGROUND: It is known that an increased intake of copper (Cu) has an adverse effect, and above all leads to the defeat of parenchymal organs, including liver tissue. AIM: This study the morphological changes in the hepatic tissue at the impact of polymetallic Cu dust. METHODS: An experimental study was carried out on the outbred white male rats. Dust was injected once intratracheally at a dose of 50 mg. For dynamic observation, the animals were killed in 1, 3, and 6 months with the control group using instant decapitation. The Balkhash industrial polymetallic dust with a predominant Cu content (Cu-0.6%) was used for the study. Morphological changes were assessed using histological and morphometric methods. RESULTS: Morphometric examination of liver tissue at 30 days showed Vv necrosis increasing in 320 times in Group 2 (p < 0.001), Vv infiltrates – in 121 times (p < 0.001), Vv dystrophic altered hepatocytes – in 19.91 times (p < 0.001), Vv dual-core cells – in 23 times (p < 0.01), and Vv fibrosis – in 2.82 times (p < 0.001) in comparison with Group 1. Vv portal tracts are not reliably changed. In 90 days, there were also the following morphometric parameters increasing in comparison with the control group: Vv necrosis – in 522 times (p < 0.001), Vv infiltrates – in 395 times (p < 0.001), Vv dystrophic altered hepatocytes – in 26.7 times (p < 0.001), Vv dual-core cells – in 314 times (p < 0.01), and Vv fibrosis – in 13.27 times (p < 0.001). On the 180 day of the experiment, there was the increasing of Vv infiltrates in 421 times (p < 0.001), Vv dystrophic altered hepatocytes – in 34.09 times (p < 0.001), Vv dual-core cells – in 411 times (p < 0.001), and Vv fibrosis – in 54.09 times (p < 0.001) CONCLUSION: The impact of polymetallic dust with 0.6% Cu concentration at the early stages leads to the changes in the liver in the form of reactive hepatitis with the following transformation into portal-type hepatitis

Experimental investigation of tsunami waves generated by granular collapse into water

The generation of a tsunami wave by an aerial landslide is investigated through model laboratory experiments. We examine the collapse of an initially dry column of grains into a shallow water layer and the subsequent generation of waves. The experiments show that the collective entry of the granular material into water governs the wave generation process. We observe that the amplitude of the wave relative to the water height scales linearly with the Froude number based on the horizontal velocity of the moving granular front relative to the wave velocity. For all the different parameters considered here, the aspect ratio and the volume of the column, the diameter and density of the grains, and the height of the water, the granular collapse acts like a moving piston displacing the water. We also highlight that the density of the falling grains has a negligible influence on the wave amplitude, which suggests that the volume of grains entering the water is the relevant parameter in the wave generation.Comment: 23 pages, 16 figure

Ab Initio No Core Shell Model - Recent Results and Further Prospects

There has been significant recent progress in solving the long-standing problems of how nuclear shell structure and collective motion emerge from underlying microscopic inter-nucleon interactions. We review a selection of recent significant results within the ab initio No Core Shell Model (NCSM) closely tied to three major factors enabling this progress: (1) improved nuclear interactions that accurately describe the experimental two-nucleon and three-nucleon interaction data; (2) advances in algorithms to simulate the quantum many-body problem with strong interactions; and (3) continued rapid development of high-performance computers now capable of performing $20 \times 10^{15}$ floating point operations per second. We also comment on prospects for further developments.Comment: Invited paper presented at NTSE-2014 and published online in the proceedings (see footnote on p.1

Top soil physical and chemical properties in Kazakhstan across a north-south gradient

Kazakhstan’s soil properties have yet to be comprehensively characterized. We sampled 40 sites consisting of ten major soil types at spring (wet) and late-summer (dry) seasons. The sample locations range from semi-arid to arid with an annual mean air temperature from 1.2 to 10.7 °C and annual precipitation from less than 200 to around 400 mm. Overall topsoil total (STC), organic (SOC), and inorganic (SIC) carbon did not change significantly between spring and late summer. STC and SOC show a wave like pattern from north to south with two maxima in northern and southern Kazakhstan and one minimum in central Kazakhstan. With a few exceptions SIC content at northern sites is generally low, whereas at Lake Balkhash SIC can exceed 75% of STC. Independent of the seasons, SOC significantly differed among soil types. Total nitrogen content distribution among our sampling sites followed a similar pattern as SOC with significant differences between soil types occurring in northern, central and southern Kazakhstan

No Core CI calculations for light nuclei with chiral 2- and 3-body forces

The atomic nucleus is a self-bound system of strongly interacting nucleons. In No-Core Configuration Interaction calculations, the nuclear wavefunction is expanded in Slater determinants of single-nucleon wavefunctions (Configurations), and the many-body Schrödinger equation becomes a large sparse matrix problem. The challenge is to reach numerical convergence to within quantified numerical uncertainties for physical observables using finite truncations of the infinite-dimensional basis space. We discuss strategies for constructing and solving the resulting large sparse matrices for a set of low-lying eigenvalues and eigenvectors on current multicore computer architectures. Several of these strategies have been implemented in the code MFDn, a hybrid MPI/OpenMP Fortran code for ab initio nuclear structure calculations that scales well to over 200,000 cores. We discuss how the similarity renormalization group can be used to improve the numerical convergence. We present results for excitation energies and other selected observables for ⁸Be and ¹²C using realistic 2- and 3-body forces obtained from chiral perturbation theory. Finally, we demonstrate that collective phenomena such as rotational band structures can emerge from these microscopic calculations