Interatomic pairwise methods are currently among the most popular and accurate ways to include dispersion energy in density functional theory calculations. However, when applied to more than two atoms, these methods are still frequently perceived to be based on ad hoc assumptions, rather than a rigorous derivation from quantum mechanics. Starting from the adiabatic connection fluctuation-dissip...

Metacognitive awareness has been shown to be a critical skill for academic success. However, students often struggle to regulate this ability during learning tasks. The current study investigates how features designed to promote metacognitive awareness can be built into the game-based intelligent tutoring system (ITS) iSTART-2. College students (n=28) interacted with iSTART-2 for one hour, comp...

We explore the difficulties with a primordial origin of variations of D/H in quasar absorption systems. In particular we examine options such as a very large-scale inhomogeneity in the baryon content of the universe. We show that very large-scale (much larger than 1 Mpc) isocurvature perturbations are excluded by current cosmic microwave background observations. Smaller-scale ad hoc perturbatio...

Planetary nebulae (PNe) are very important kinematical tracers of the outer regions of early-type galaxies, where the integrated light techniques fail. Under ad hoc assumptions, they allow measurements of rotation velocity and velocity dispersion profile from descrete radial velocity fields. We present the results on the precision allowed by different set of radial velocity samples, discuss the...

We propose heading-aware methods of generating search result snippets of web pages. A heading is a brief description of the topic of its associated sentences. Some existing methods give priority to sentences containing many words that also appear in headings when selecting sentences to be included in snippets with limited length. However, according to our observation, words in heading are very ...

Phenomena in the performance behaviour of high-performance computing (HPC) applications can stem from the HPC system itself, from the application’s code, but also from the simulation domain. In order to analyse the latter phenomena, we propose a system that visualizes profile-based performance data in its spatial context, i.e., on the geometry, in the simulation domain. It thus helps HPC expert...

In this work, the role of degree acetalization polyvinylbutyral (PVB) on dynamic mechanical properties PVB nanocomposites was evaluated. Nanocomposites reinforced with carbon nanoparticles (pristine or oxidized multiwalled nanotubes, graphene oxide and nanoplatelets) were prepared by in situ addition during synthesis from polyvinyl alcohol. It found that presence nanoreinforcements considerably...

We have carried out a study of the velocity dispersion of the stars in the outskirts of the globular cluster ω Cen, finding that the velocity dispersion remains constant at large radii rather than decrease monotonically. The dispersion starts to be constant for an acceleration of gravity of a = 2.1 +0.5 −0.4 × 10 −8 cm s −2. A similar result is obtained reanalyzing existing data for the globula...

The structure and dynamics of enigmatic hexa(3,5-di-tert-butylphenyl)ethane was characterized via NMR spectroscopy for the first time. Our variable temperature NMR analysis demonstrates an enthalpy-entropy compensation that results in a vanishingly low dissociation energy (ΔG298d = -1.60(6) kcal mol-1). An in silico study of increasingly larger all-meta alkyl substituted hexaphenylethane deriva...

We perform differential expression analysis of high-throughput sequencing count data under a Bayesian nonparametric framework, removing sophisticated ad-hoc pre-processing steps commonly required in existing algorithms. We propose to use the gamma (beta) negative binomial process, which takes into account different sequencing depths using sample-specific negative binomial probability (dispersio...