Level frequency postulate and the dice analog.

A level frequency postulate is proposed in the context of the Onsager regression hypothesis, and is utilized to demonstrate Fourier fluctuation time between levels in an analog system composed of red and white dice. This dice system is shown to be analogous to an isolated composite system of particles through derivation of the level probability distribution. Level fluctuation time is developed as an algebraic expression involving average energy and a Gaussian parameter, with quasistatic evolution demonstrated as an integral over fluctuation time.

A Qualitative Interview Study of Distributed Tracing Visualisation: A Characterisation of Challenges and Opportunities.

Distributed tracing tools have emerged in recent years to enable operators of modern internet applications to troubleshoot cross-component problems in deployed applications. Due to the rich, detailed diagnostic data captured by distributed tracing tools, effectively presenting this data is important. However, use of visualisation to enable sensemaking of this complex data in distributed tracing tools has received relatively little attention. Consequently, operators struggle to make effective use of existing tools. In this paper we present the first characterisation of distributed tracing visualisation through a qualitative interview study with six practitioners from two large internet companies. Across two rounds of 1-on-1 interviews we use grounded theory coding to establish users, extract concrete use cases and identify shortcomings of existing distributed tracing tools. We derive guidelines for development of future distributed tracing tools and expose several open research problems that have wide reaching implications for visualisation research and other domains.

Biindanylidenes: role of central bond torsion in nonvertical triplet excitation transfer to the stilbenes.

The stilbenes were proposed to function as nonvertical triplet excitation (NVET) acceptors for energy-deficient donors because rotation about the central bond diminishes the energy gap between ground and triplet energy surfaces. Recently, the role of central bond torsion in facilitating NVET to cis-stilbene (c-St) was questioned because the behavior of 2,3-diphenylnorbornene as a triplet energy acceptor is similar to that of cis-stilbene. On the basis of the assumption that the rigidity of the norbornene skeleton precludes torsional displacement of the phenyl rings in the triplet state, an alternative mechanism was proposed involving phenyl-vinyl torsion as the key reaction coordinate for NVET to c-St. However, this proposal is inconsistent with theory, which predicts that the triplet state energy minimum corresponds to a geometry with significant displacement of the phenyl rings of 2,3-diphenylnorbornene from a common plane. We now provide experimental evidence demonstrating that central bond torsion is the key coordinate for NVET to stilbenes. Comparison of the activation parameters for the two rigid stilbene analogues, cis- and trans-1,1'-biindanylidene (c-Bi and t-Bi) to those for the stilbenes, shows that the excitation transfer processes remain nonvertical despite the strong structural inhibition of phenyl-vinyl torsion; the relatively small preexponential factors of the respective isomers are almost identical. Their magnitude is a measure of the attenuation introduced by Franck-Condon overlap factors which decrease as the torsional state quantum number corresponding to the transition state increases. These results and results from theoretical calculations are consistent with central bond torsion as the key reaction coordinate in NVET to the biindanylidenes and the stilbenes. The crystal structure of t-Bi shows it to be strictly planar, eliminating phenyl-vinyl torsion toward planarity as a crucial NVET reaction coordinate.