Spectrum, Winter 1992

Spectrum was a newsletter for students, faculty, staff and alumni of the Henry M. Goldman School of Dental Medicine, published from 1983-1992

Tidal controls on the lithospheric thickness and topography of Io from magmatic segregation and volcanism modelling

Tidal heating is expected to impart significant, non-spherically-symmetric structure to Jupiter's volcanic moon Io. A signature of spatially variable tidal heating is generally sought in observations of surface heat fluxes or volcanic activity, an exploration complicated by the transient nature of volcanic events. The thickness of the lithosphere is expected to change over much longer timescales, and so may provide a robust link between surface observations and the tidal heating distribution. To predict long-wavelength lithospheric thickness variations, we couple three-dimensional tidal heating calculations to a suite of one-dimensional models of magmatic segregation and volcanic eruption. We find that the lithospheric thickness could either be correlated with the radially integrated heating rate, or weakly anti-correlated. Lithospheric thickness is correlated with radially integrated heating rate if magmatic intrusions form at a constant rate in the lithosphere, but is weakly anti-correlated if intrusions form at a rate proportional to the flux through volcanic conduits. Utilising a simple isostasy model we show how variations in lithospheric thickness can predict long-wavelength topography. The relationship between lithospheric thickness and topography depends on the difference in chemical density between the lithosphere and mantle. Assuming that this difference is small, we find that long-wavelength topography anti-correlates with lithospheric thickness. These results will allow future observations to critically evaluate models for Io's lithospheric structure, and enable their use in constraining the distribution of tidal heating.Comment: Published in Icaru

The Agency of the Translator: Khalil Baydas' Literary Translations.

This dissertation examines the translation practice of Khalil Baydas (1875-1949), Palestinian writer, translator, and journalist. Baydas translated dozens of novels and short stories from Russian into Arabic. Literary translation made up a large part of Arabic literature published during the nahḍah, the Arab literary renaissance of the 19th century. However, these translations are dismissed because they often drift far from their source texts. This practice, known as al-tarjamah bi-taṣarruf, acknowledges the alterations that the translator makes while translating. Using the translation theory of Lawrence Venuti, this dissertation works to read the space between the translation and the translated text in a new way. Rather than comparing the two texts to measure the fidelity of the translation, this dissertation focuses on the choices that Baydas makes as a translator. In each text considered, we see distinct patterns in the changes that Baydas makes to the source text. To contextualize these decisions, I pair each translation discussed with a selection of articles from Baydas’ journal al-nafa’is al-‘asriyyah that treat those topics that shape his decisions as a translator. I pair close readings of three of Baydas’ novel-length translations with selections from the nonfiction articles from his literary journal al-nafa’is al-‘aṣriyyah that contextualize the decisions that Baydas makes in each of his translations. I pair my reading of Baydas’ translation of Alexander Pushkin’s Captain’s Daughter with the articles he published on national identity, a complicated question for Arabs living in the Ottoman Empire. Next, I read the alterations that Baydas makes in Marie Corelli’s novel Temporal Power together with the articles he published on education in al-nafa’is. Finally, I discuss Baydas’ translation of Aleksei Tolstoy’s Prince Serebrianiy. Using Georg Lukacs’ theories of the relationship between historical fiction and national identity, I examine the ways in which Baydas manipulates history in his fiction and nonfiction. In each case, the connections between Baydas’ alterations to his source texts and the nonfiction articles that he publishes show how deliberate and disciplined his translation practice was, opening the door for a new consideration of the place of translation in the development of modern Arabic literature.PHDNear Eastern StudiesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/96110/1/spensco_1.pd

TreeBASIS Feature Descriptor and Its Hardware Implementation

This paper presents a novel feature descriptor called TreeBASIS that provides improvements in descriptor size, computation time, matching speed, and accuracy. This new descriptor uses a binary vocabulary tree that is computed using basis dictionary images and a test set of feature region images. To facilitate real-time implementation, a feature region image is binary quantized and the resulting quantized vector is passed into the BASIS vocabulary tree. A Hamming distance is then computed between the feature region image and the effectively descriptive basis dictionary image at a node to determine the branch taken and the path the feature region image takes is saved as a descriptor. The TreeBASIS feature descriptor is an excellent candidate for hardware implementation because of its reduced descriptor size and the fact that descriptors can be created and features matched without the use of floating point operations. The TreeBASIS descriptor is more computationally and space efficient than other descriptors such as BASIS, SIFT, and SURF. Moreover, it can be computed entirely in hardware without the support of a CPU for additional software-based computations. Experimental results and a hardware implementation show that the TreeBASIS descriptor compares well with other descriptors for frame-to-frame homography computation while requiring fewer hardware resources

Definite orthogonal modular forms:Computations, Excursions and Discoveries

We consider spaces of modular forms attached to definite orthogonal groups of low even rank and nontrivial level, equipped with Hecke operators defined by Kneser neighbours. After reviewing algorithms to compute with these spaces, we investigate endoscopy using theta series and a theorem of Rallis. Along the way, we exhibit many examples and pose several conjectures. As a first application, we express counts of Kneser neighbours in terms of coefficients of classical or Siegel modular forms, complementing work of Chenevier-Lannes. As a second application, we prove new instances of Eisenstein congruences of Ramanujan and Kurokawa-Mizumoto type

Photoswitchable Phase Separation and Oligonucleotide Trafficking in DNA Coacervate Microdroplets

International audienceCoacervate micro-droplets produced by liquid-liquid phase separation have been used as synthetic protocells that mimic the dynamical organization of membrane-free organelles in living systems. Achieving spatiotemporal control over droplet condensation and disassembly remains challenging. Herein, we describe the formation and photo-switchable behaviour of light-responsive coacervate droplets prepared from mixtures of double-stranded DNA and an azobenzene cation. The droplets disassemble and reassemble under UV and blue light, respectively, due to azobenzene trans/cis photo-isomerisation. Sequestration and release of captured oligonucleotides follows the dynamics of phase separation such that light-activated transfer, mixing, hybridization and trafficking of the oligonucleotides can be controlled in binary populations of the droplets. Our results open perspectives for the spatiotemporal control of DNA coacervates and provide a step towards the dynamic regulation of synthetic protocells

Nitrogen Release and Disease Suppressive Activity of Four Compost Amendments on Three Vegetable Farms

This is a compilation of 30 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included

Social Media & Teacher Professional Development

The idea of social media’s existing application and future potential for professional development drives a growing subset of academic research. As we encourage preservice and inservice teachers to engage in these platforms to hone or refine their classroom practice, a number of questions emerge: How do we assess participation in these spaces? What uses in particular should we recommend? Further, the very notion of conducting research in these spaces also poses interesting questions. From methodologies to frameworks, commonly accepted practices help shape the future of the field. Lastly, the issue of privacy and policy poses perhaps the most significant area for attention. The intent of this panel discussion is generate conversation on how future research and application on social media usage and research might evolve over time

Adiposity induces lethal cytokine storm after systemic administration of stimulatory immunotherapy regimens in aged mice.

Aging is a contributing factor in cancer occurrence. We recently demonstrated that systemic immunotherapy (IT) administration in aged, but not young, mice resulted in induction of rapid and lethal cytokine storm. We found that aging was accompanied by increases in visceral fat similar to that seen in young obese (ob/ob or diet-induced obese [DIO]) mice. Yet, the effects of aging and obesity on inflammatory responses to immunotherapeutics are not well defined. We determine the effects of adiposity on systemic IT tolerance in aged compared with young obese mice. Both young ob/ob- and DIO-generated proinflammatory cytokine levels and organ pathologies are comparable to those in aged ad libitum mice after IT, culminating in lethality. Young obese mice exhibited greater ratios of M1/M2 macrophages within the peritoneal and visceral adipose tissues and higher percentages of TNF(+) macrophages in response to αCD40/IL-2 as compared with young lean mice. Macrophage depletion or TNF blockade in conjunction with αCD40/IL-2 prevented cytokine storms in young obese mice and protected from lethality. Calorie-restricted aged mice contain less visceral fat and displayed reduced cytokine levels, protection from organ pathology, and protection from lethality upon αCD40/IL-2 administration. Our data demonstrate that adiposity is a critical factor in the age-associated pathological responses to systemic anti-cancer IT