659 research outputs found

    Bethe-Salpeter Equation Calculations of Core Excitation Spectra

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    We present a hybrid approach for GW/Bethe-Salpeter Equation (BSE) calculations of core excitation spectra, including x-ray absorption (XAS), electron energy loss spectra (EELS), and non-resonant inelastic x-ray scattering (NRIXS). The method is based on {\it ab initio} wavefunctions from the plane-wave pseudopotential code ABINIT; atomic core-level states and projector augmented wave (PAW) transition matrix elements; the NIST core-level BSE solver; and a many-pole GW self-energy model to account for final-state broadening and self-energy shifts. Multiplet effects are also accounted for. The approach is implemented using an interface dubbed OCEAN (Obtaining Core Excitations using ABINIT and NBSE). To demonstrate the utility of the code we present results for the K-edges in LiF as probed by XAS and NRIXS, the K-edges of KCl as probed by XAS, the Ti L_2,3-edge in SrTiO_3 as probed by XAS, and the Mg L_2,3-edge in MgO as probed by XAS. We compare the results to experiments and results obtained using other theoretical approaches

    Symmetry Breaking in Jetting

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    In the bubble-jet printing process, it has been observed that the drop that ultimately pinches off from the ink jet sometimes moves sideways rather than straight relative to the symmetry axis of the liquid jet. We examined various mechanisms that might lead to the deflection of the ink drop. In particular, we focused on whether the liquid filament that connects the lead drop to the nozzle is capable of supporting lateral waves which might propagate from the nozzle toward the lead drop and break the symmetry at pinch-off

    Fully-dynamic Approximation of Betweenness Centrality

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    Betweenness is a well-known centrality measure that ranks the nodes of a network according to their participation in shortest paths. Since an exact computation is prohibitive in large networks, several approximation algorithms have been proposed. Besides that, recent years have seen the publication of dynamic algorithms for efficient recomputation of betweenness in evolving networks. In previous work we proposed the first semi-dynamic algorithms that recompute an approximation of betweenness in connected graphs after batches of edge insertions. In this paper we propose the first fully-dynamic approximation algorithms (for weighted and unweighted undirected graphs that need not to be connected) with a provable guarantee on the maximum approximation error. The transfer to fully-dynamic and disconnected graphs implies additional algorithmic problems that could be of independent interest. In particular, we propose a new upper bound on the vertex diameter for weighted undirected graphs. For both weighted and unweighted graphs, we also propose the first fully-dynamic algorithms that keep track of such upper bound. In addition, we extend our former algorithm for semi-dynamic BFS to batches of both edge insertions and deletions. Using approximation, our algorithms are the first to make in-memory computation of betweenness in fully-dynamic networks with millions of edges feasible. Our experiments show that they can achieve substantial speedups compared to recomputation, up to several orders of magnitude

    Π”ΠΈΡ„Ρ„Π΅Ρ€Π΅Π½Ρ†ΠΈΠ°Π»ΡŒΠ½ΠΎβˆ’Π΄ΠΈΠ°Π³Π½ΠΎΡΡ‚ΠΈΡ‡Π΅ΡΠΊΠΈΠ΅ нСйрофизиологичСскиС коррСляты ΡΠΌΠΎΡ†ΠΈΠΎΠ½Π°Π»ΡŒΠ½ΠΎβˆ’Π»ΠΈΡ‡Π½ΠΎΡΡ‚Π½Ρ‹Ρ… ΠΈ повСдСнчСских расстройств Ρƒ подростков с ΠΌΠΎΠ·Π³ΠΎΠ²ΠΎΠΉ дисфункциСй

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    ΠŸΡ€Π΅Π΄ΡΡ‚Π°Π²Π»Π΅Π½Ρ‹ Ρ€Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ‹ исслСдования Ρ„ΡƒΠ½ΠΊΡ†ΠΈΠΎΠ½Π°Π»ΡŒΠ½ΠΎΠΉ активности Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π° Ρƒ подростков с ΠΌΠΎΠ·Π³ΠΎΠ²ΠΎΠΉ дисфункциСй ΠΈ ΡΠΌΠΎΡ†ΠΈΠΎΠ½Π°Π»ΡŒΠ½Ρ‹ΠΌΠΈ, личностными, повСдСнчСскими расстройствами. ВыявлСны нСйрофизиологичСскиС коррСляты ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ Ρ…Π°Ρ€Π°ΠΊΡ‚Π΅Ρ€Π° ΠΈ повСдСния Π±ΠΎΠ»ΡŒΠ½Ρ‹Ρ… подростков.The findings of brain functional activity investigation in teenagers with cerebral dysfunction as well as emotional, personality, behavioral disorders are reported. Neurophysiological correlates of the character and behavior changes in teenβˆ’agers were revealed

    Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa

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    Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. To date, only one genome-wide significant locus associated with AN has been identified. We performed an exome-chip based genome-wide association studies (GWAS) in 2158 cases from nine populations of European origin and 15 485 ancestrally matched controls. Unlike previous studies, this GWAS also probed association in low-frequency and rare variants. Sixteen independent variants were taken forward for in silico and de novo replication (11 common and 5 rare). No findings reached genome-wide significance. Two notable common variants were identified: rs10791286, an intronic variant in OPCML (P=9.89 Γ— 10βˆ’6), and rs7700147, an intergenic variant (P=2.93 Γ— 10βˆ’5). No low-frequency variant associations were identified at genome-wide significance, although the study was well-powered to detect low-frequency variants with large effect sizes, suggesting that there may be no AN loci in this genomic search space with large effect sizes
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