659 research outputs found
Bethe-Salpeter Equation Calculations of Core Excitation Spectra
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
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
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
ΠΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΠΎβΠ΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π½Π΅ΠΉΡΠΎΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΊΠΎΡΡΠ΅Π»ΡΡΡ ΡΠΌΠΎΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎβΠ»ΠΈΡΠ½ΠΎΡΡΠ½ΡΡ ΠΈ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΡΠ΅ΡΠΊΠΈΡ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ² Ρ ΠΏΠΎΠ΄ΡΠΎΡΡΠΊΠΎΠ² Ρ ΠΌΠΎΠ·Π³ΠΎΠ²ΠΎΠΉ Π΄ΠΈΡΡΡΠ½ΠΊΡΠΈΠ΅ΠΉ
ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠΉ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π° Ρ ΠΏΠΎΠ΄ΡΠΎΡΡΠΊΠΎΠ² Ρ ΠΌΠΎΠ·Π³ΠΎΠ²ΠΎΠΉ Π΄ΠΈΡΡΡΠ½ΠΊΡΠΈΠ΅ΠΉ ΠΈ ΡΠΌΠΎΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΠΌΠΈ, Π»ΠΈΡΠ½ΠΎΡΡΠ½ΡΠΌΠΈ, ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ²Π°ΠΌΠΈ. ΠΡΡΠ²Π»Π΅Π½Ρ Π½Π΅ΠΉΡΠΎΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΊΠΎΡΡΠ΅Π»ΡΡΡ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠ° ΠΈ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ Π±ΠΎΠ»ΡΠ½ΡΡ
ΠΏΠΎΠ΄ΡΠΎΡΡΠΊΠΎΠ².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 teenβagers were revealed
Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa
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 15β485 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 10β6), and rs7700147, an intergenic variant (P=2.93 Γ 10β5). 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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