Theophilus' On Diverse Arts: The Persona of the Artist and the Production of Art in the Twelfth Century.

De diversis artibus (On Diverse Arts) is one of the rare tracts on art and art-making to survive from the Middle Ages. Written by a monk using the pseudonym Theophilus, dated to the early twelfth century, and localized to northern Germany, the treatise comprises three books of instructions on the arts of painting, glass, and metalwork, each introduced by a prologue. Eight nearly complete copies of the text survive, including two from the mid-twelfth century. Seventeen additional manuscripts preserve either incomplete copies or excerpts. Drawing on the evidence of all these manuscripts, the dissertation examines how the text may have been read and understood in its twelfth-century context and later, and what it might reveal about attitudes toward art-making. When prologues and instructions are studied together, On Diverse Arts emerges as an integrated, carefully structured text with a sophisticated agenda. Emphasizing material hierarchies and spiritual ascent, it effectively unifies the theory and practice of art. The first chapter of the dissertation introduces the manuscript copies of On Diverse Arts and follows the remarkable story of its reception over the centuries: manuscripts were avidly collected and read by artisans, humanists, and antiquarians, and their interests still affect our own. The second chapter draws evidence from one early manuscript to uncover the internal structure of the text and to set the stage for a discussion of the parallels between On Diverse Arts and contemporary pedagogical and exegetical literature. The third chapter reexamines the identification of Theophilus as the monastic artisan Roger of Helmarshausen in the oldest copy of the text. I propose that the memory of the artist gave specific meaning to style and ornament in a network of monasteries, and I thereby I redirect questions of identity to issues of memory. The fourth chapter starts with one manuscript’s marginal notations to demonstrate how Theophilus’ tract moralizes the labor of the artist, transforming art-making into the practice of virtue or vice. Finally, the fifth chapter draws upon a composite manuscript to shed light on the variable generic status of On Diverse Arts and the place of art-making within medieval schemes of knowledge.Ph.D.History of ArtUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75830/1/heididi_1.pd

HD 71636, A Newly Discovered Eclipsing Binary

Our differential BV photometric observations, acquired with an automated telescope at Fairborn Observatory, show that HD 71636 is an eclipsing binary. From follow-up red-wavelength spectroscopic observations we classify the primary and secondary as an F2 dwarf and an F5 dwarf, respectively. The system has a period of 5.01329 days and a circular orbit. We used the Wilson-Devinney program to simultaneously solve our BV light curves and radial velocities and determined a number of fundamental properties of the system. Comparison with evolutionary tracks indicates that both stars are well ensconced on the main sequence. The age of the system is about 1.2 billion years

Selective Vulnerability of the Cochlear Basal Turn to Acrylonitrile and Noise

Exposure to acrylonitrile, a high-production industrial chemical, can promote noise-induced hearing loss (NIHL) in the rat even though this agent does not itself produce permanent hearing loss. The mechanism by which acrylonitrile promotes NIHL includes oxidative stress as antioxidant drugs can partially protect the cochlea from acrylonitrile + noise. Acrylonitrile depletes glutathione levels while noise can increase the formation of reactive oxygen species. It was previously noted that the high-frequency or basal turn of the cochlea was particularly vulnerable to the combined effects of acrylonitrile and noise when the octave band noise (OBN) was centered at 8 kHz. Normally, such a noise would be expected to yield damage at a more apical region of the cochlea. The present study was designed to determine whether the basal cochlea is selectively sensitive to acrylonitrile or whether, by adjusting the frequency of the noise band, it would be possible to control the region of the auditory impairment. Rats were exposed to one of three different OBNs centered at different frequencies (4 kHz, 110 dB and 8 or 16 kHz at 97 dB) for 5 days, with and without administration of acrylonitrile (50 mg/kg/day). The noise was set to cause limited NIHL by itself. Auditory function was monitored by recording distortion products, by compound action potentials, and by performing cochlear histology. While the ACN-only and noise-only exposures induced no or little permanent auditory loss, the three exposures to acrylonitrile + noise produced similar auditory and cochlear impairments above 16 kHz, despite the fact that the noise exposures covered 2 octaves. These observations show that the basal cochlea is much more sensitive to acrylonitrile + noise than the apical partition. They provide an initial basis for distinguishing the pattern of cochlear injury that results from noise exposure from that which occurs due to the combined effects of noise and a chemical contaminant