Lloyd C. Engelbrecht (born 1927) is Professor Emeritus of Art History at the University of Cincinnati. He is author of Moholy-Nagy: Mentor to Modernism (Cincinnati: Flying Trapeze Press, 2009). He will supply addenda and corrigenda for this book on a continuing basis.
The foreground Veil of material that lies in front of the Orion Nebula is the best studied sample of the interstellar medium because we know where it is located, how it is illuminated, and the balance of thermal and magnetic energy. In this work, we present high-resolution STIS observations toward the Trapezium, with the goal of better understanding the chemistry and geometry of the two primary Veil layers, along with ionized gas along the line of sight. The most complete characterization of the rotational/vibrational column densities of H2 in the almost purely atomic components of the Veil are presented, including updates to the Cloudy model for H2 formation on grain surfaces. The observed H2 is found to correlate almost exclusively with Component B. The observed H2, observations of CI, CI*, and CI**, and theoretical calculations using Cloudy allow us to place the tightest constraints yet on the distance, density, temperature, and other physical characteristics for each cloud component. We ﬁnd the H2 excitation spectrum observed in the Veil is incompatible with a recent study that argued that the Veil was quite close to the Trapezium. The nature of a layer of ionized gas lying between the Veil and the Trapezium is characterized through the emission and absorption lines it produces, which we ﬁnd to be the blueshifted component observed in S III and P III absorption. We deduce that, within the next 30–60 thousand years, the blueshifted ionized layer and Component B will merge, which will subsequently merge with Component A in the next one million years.
The purpose of this study was to define and examine the IASB’s
governance network. The IASB’s governance network was bound to include 14
organisational members and 407 individual actors. I used social network
methodology to examine the professional and geographic perspectives
represented as well as the extent to which the governance network was
structurally embedded. It was found that the network forms a definable
hierarchy that exhibits qualities of structural embeddedness. Banking interests
were more embedded within the governance network than any other
professional, academic, or social group. Also, a strong Western influence was
detected. The societal benefit of this effort was to engage society in general and
accounting researchers in particular in hopes of encouraging discourse about
regulatory processes with both macro and micro consequences.
Several constitutive theories have been proposed in the literature to model the viscoelastic response of soft tissue, including widely used rheological constitutive models. These models are characterized by certain parameters (“time constants”) that define the time scales over which the tissue relaxes. These parameters are primarily obtained from stress relaxation experiments using curve-fitting techniques. However, the question of how best to estimate these time constants remains open.
As a step towards answering this question, we develop an optimal experimental design approach based on ideas from information geometry, namely Fisher information and Kullback-Leibler divergence. Tissue is modeled as a standard linear solid and described using a one- or two-term Prony series. Treating the time constants as unknowns, we develop expressions for the Fisher information and Kullback-Leibler divergence that allow us to maximize information gain from experimental data. Based on the results of this study, we propose that the largest time constant estimated from a stress relaxation experiment for a linear viscoelastic material should be at most one-fifth of the total time of the experiment in order to maximize information gain.