Some geodesic problems in groups

We consider several algorithmic problems concerning geodesics in finitely generated groups. We show that the three geodesic problems considered by Miasnikov et al [arXiv:0807.1032] are polynomial-time reducible to each other. We study two new geodesic problems which arise in a previous paper of the authors and Fusy [arXiv:0902.0202] .Comment: 6 page

\u27Very Quiet Day, Vague Tension\u27: Digitizing and Sharing the Stories of School Desegregation and Busing in Boston

In the summer of 2015, University Archives & Special Collections at UMass Boston began to work with a number of area archival institutions to create “a digital library of material that can be widely disseminated for both curricular and scholarly use” related to the history of school desegregation and busing in Boston. Too often, the history of Boston school desegregation seems weighted down by some of the most visible characters involved – politicians, policy-makers, court officials – so we decided early on to focus largely on identifying materials that tell a more complex, personal history of school desegregation and busing in Boston. After reviewing the range of materials in our care and the myriad rights issues involved, we decided to focus on two collections: the records of Mosaic, a program out of South Boston High School from 1980 to 1989, and the chambers papers of Judge Arthur Garrity, the federal district court judge who oversaw the Boston Schools case

Random subgroups of Thompson's group FF

We consider random subgroups of Thompson's group $F$ with respect to two natural stratifications of the set of all $k$ generator subgroups. We find that the isomorphism classes of subgroups which occur with positive density are not the same for the two stratifications. We give the first known examples of {\em persistent} subgroups, whose isomorphism classes occur with positive density within the set of $k$-generator subgroups, for all sufficiently large $k$. Additionally, Thompson's group provides the first example of a group without a generic isomorphism class of subgroup. Elements of $F$ are represented uniquely by reduced pairs of finite rooted binary trees. We compute the asymptotic growth rate and a generating function for the number of reduced pairs of trees, which we show is D-finite and not algebraic. We then use the asymptotic growth to prove our density results.Comment: 37 pages, 11 figure

Optimization of Dissolved Air Flotation for Algal Harvesting at the Logan, Utah Wastewater Treatment Plant

This research evaluated dissolved air flotation (DAF) as a separation method for algae and phosphorus from municipal wastewater at the City of Logan, Utah Wastewater Reclamation Facility. DAF uses the supersaturation of air to raise suspended algae and other particles to the surface, where they can be easily removed. DAF, in conjunction with chemical coagulants and flocculants, can approach 95% algae and phosphorus removal. The algae removed using the DAF process will be used in the production of biofuels and bioplastics. A pilot DAF unit was used to determine the optimum alum dose for total phosphorus (TP) and algae removal. In addition, a bench-scale jar test unit was used to study the effects of various alum and polymer doses on removal efficiencies at different times of the day. An optimal alum dose was found to be 30 mg/L based on results from both the pilot and bench-scale units. No advantage to adding polymer was found. Algae removal efficiencies on the pilot DAF ranged from 68-70%, and the effluent algae concentration was reduced to 10 mg/L. Approximately 65% of the total phosphorus was removed, from 1.1 to 0.4 mg/L, which is low enough to meet regulations anticipated to be promulgated by the state of Utah. Using the assumption that the molar weight of algae is 3,550 g/mole, the molar ratio of Al/TSS was found to be 30.1 and the molar ratio of Al/TP was found to be 7.5. Extracellular polymeric substances (EPS) excreted by algal cells act as a natural flocculant and may allow for chemical usage to be minimized. Autoflocculation and bioflocculation, natural processes caused by EPS production and an increased pH level, were not observed to be a significant factor. The chemical dosing rates provide the City of Logan with basic operational parameters for a full-scale (15 million gallons per day) DAF plant, providing an effluent phosphorus level below 0.5 mg/L. The alum will cost $1,118 per day, with a daily electrical cost of approximately$149. This full-scale DAF plant would harvest 1,563 kg of algal biomass per day, with a cost per kilogram of algae at $0.81

Functionality of red blood cells after cryo-preservation.

One of the most common medical procedures performed in US hospitals is blood transfusions. Unfortunately, the red blood cells (RBCs) for transfusion have a limited shelf life after donation due to detrimental storage effects on morphological and biochemical properties. Inspired by nature, I am developing a biomimetics approach to preserve RBCs for long-term storage using compounds that occur in animals that have developed a natural propensity to survive in a frozen or desiccated state for decades. Trehalose was employed as a cryoprotective agent when added to the extracellular freezing solution. The highest percent of RBCs with intact membranes after freezing and thawing was obtained using a cryopreservation solution comprised of 250 million RBCs/mL, 300 mM trehalose, 100 mM NaCl, in 20 mM HEPES buffer, pH 7.1. Under these conditions RBCs with intact membranes were recovered at 86 ± 12%. I have demonstrated the effectiveness and feasibility of using trehalose as a cryoprotective agent, and morphological intact RBCs were recovered after freezing and thawing with low cellular loss

The Media Matrix of Early Jewish and Christian Literature

This study compares two seemingly dissimilar ancient texts, the Gospel of Mark and Joseph and Aseneth. The former is a product of the nascent Jesus movement and influenced by the Greco-Roman βίοι (“Lives”). It details the life, ministry, death, and resurrection of a wandering Galilean. The latter is a Hellenistic Jewish narrative influenced by Jewish novellas and Greek romances. It expands the laconic account of Joseph’s marriage to Aseneth in Genesis 41 into a full-blown love story that promotes the romantic, theological, and ethical incentives of spurning idols and converting to Judaism. Generically, theologically, and concerning content the two texts are quite different. Nonetheless, Mark and Joseph and Aseneth exhibit a number of remarkable affinities. As to language and style, both are paratactically structured and contain few long, complex periods. They are repetitive with respect to words, clauses, sentences, and pericopes. Each employs a similar proportion of active to passive voice verbs, as well as present and imperfect to aorist tenses. They are similar in length, and the direction of each narrative dramatically shifts at its midway point. Both are intertextually echoic, evoking Jewish Scriptures metonymically rather than by direct citation. And each has a multiform textual tradition that went unprotected from dramatic revisions by later authors and editors. I argue that Mark and Joseph and Aseneth are similar in these respects because of their medium and mode of composition. Each was composed via dictation. They are what I will call “textualized oral narratives.” As such they represent one instantiation of the complex relationship between orality and textuality in early Judaism and Christianity. This thesis is argued on the basis of modern sociolinguistic studies that compare oral and written narratives, considerations of ancient media culture, and the linguistic and metalinguistic characteristics of the texts themselves

Using the Internet for community analysis: county data sources for western states

November 2002

Economic profile of Kiowa County.

November 2002.Includes bibliographical references