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Apuleius' Metamorphoses (or The Golden Ass), a masterpiece of Latin literature from the second century AD, still captivates modern readers with its combination of asininity and mysticism. In the novel, a young man named Lucius tells how he accidentally turns into a donkey and then describes how he regains human form with the help of the Egyptian goddess Isis, into whose cult he is initiated. This book argues that invisibility is one of the central motifs in the Metamorphoses and, in the process, presents a new interpretation of Apuleius' novel as a visionary, esoteric text. It contributes both to the study of the subtle relationship between literature and Platonic philosophy and to the cultural history of invisibility in classical antiquity and beyond.
An array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.
The transition temperatures of solid-solid phase changes in selected polyalcohols, “plastic crystals,” can be adjusted by using interstitial and substitutional dopants. An investigation is under way of the structural changes in these during heating and cooling, and of the thermodynamic properties such as the transition, temperatures and enthalpy changes, as a function of the percent of dopant. The purpose of the investigation is to find and evaluate materials having potential value In thermal storage applications. Dopants for pentaerythritol discussed in this report are trimethylolpropane (TMP), ammonia, boron trifluoride, pentaglycerine (PG) and neopentylglycol (NPG).
The implementation of farm to school programs and the use of local foods in US school meals have increased dramatically since the 1990s. However, supply constraints are often cited by school districts as an impediment to purchasing local foods. In this paper, we estimate the responsiveness of local food sourcing by schools in response to changes in local agricultural production. We test several hypotheses by merging data from the nationally administered 2015 Farm to School Census, which solicits information about local food sourcing from school districts, with Census of Agriculture data and other socio-economic data. We test whether local agricultural conditions influence the probability that a school district sources local foods, as well as the level of such purchases among the subset of school districts that are buying locally. We examine two types of local food purchases: local fluid milk purchases, which is the predominate food product that is locally sourced by schools, and local non-milk food purchases. We test the extent to which local purchases are influenced by local dairy production in the former case and local direct-to-consumer (DTC) agricultural production in the latter case. We find that the dairy and DTC agricultural production had a positive, although modest, impact on local milk and local non-milk purchases, respectively.
We find that county-level average income and the percentage of residents in poverty, when statistically significant, had positive and negative, respectively, impacts on local sourcing. Interpreting the coefficients on some of our other control variables involves greater nuance. For instance, while the percentage of students eligible for free and reduced-price meals decreases the predicted probability of a school making local non-milk purchases, it has a positive impact on the level of expenditures. We also find that the number of students in a school district has a positive impact on local food expenditures. However, while county-level population has a positive impact on local food expenditures, it has a negative impact on the predicted probability that a school district sources local non-milk products.
Superluminal motions were first seen in 3C 120 between 1972.5 and 1974.4 (Seielstad et al. 1979 and references therein). Between 1975 and 1980, the source was monitored along with 3C 273 and 3C 345 by the Caltech group. One reasonably clear episode of expansion was seen in 1979 (Walker et al. 1982) but, for most of the time, the source evolution was so rapid that it was difficult to relate the structures seen at successive epochs.
We present VLBI and VLA maps of the superluminal radio source 3C 120 (z = 0.03). The 18 cm VLBI maps shown in Figures 1 and 2c were constructed from a 14 station VLBI observation on 10, 11 October 1982. The map in Figure 1 is at full spatial resolution. The Figure 2c map was made from a uv-tapered data set and shows the extended emission. The VLBI maps show a jet ~175 pc long with distinct knots and bends (H0 = 55 kms−1 Mpc−1). The 18 cm jet smoothly connects to the 6 cm superluminal jet (Figure 2d). The VLBI jet remains well collimated through several bends and only begins to spread out 100 pc beyond the core. At 175 pc from the core, the jet is wide and weak, and disappears into the under-sampled region of the uv-plane (< 2(10)6 λ's).
The jet in the superluminal source 3C 120 has been observed on all scales from under a parsec to about 100 kpc. The jet brightness decays rather smoothly with core distance, indicating that the basic characteristics of the jet are established on parsec or smaller scales and evolve simply with distance.