Numerical methods and analysis for continuous data assimilation in fluid models

Modeling fluid flow arises in many applications of science and engineering, including the design of aircrafts, prediction of weather, and oceanography. It is vital that these models are both computationally efficient and accurate. In order to obtain good results from these models, one must have accurate and complete initial and boundary conditions. In many real-world applications, these conditions may be unknown, only partially known, or contain error. In order to overcome the issue of unknown or incomplete initial conditions, mathematicians and scientists have been studying different ways to incorporate data into fluid flow models to improve accuracy and/or speed up convergence to the true solution. In this thesis, we are studying one specific data assimilation technique to apply to finite element discretizations of fluid flow models, known as continuous data assimilation. Continuous data assimilation adds a penalty term to the differential equation to nudge coarse spatial scales of the algorithm solution to coarse spatial scales of the true solution (the data). We apply continuous data assimilation to different algorithms of fluid flow, and perform numerical analysis and tests of the algorithms

Survival of Fecal Coliforms and Fecal Streptococci in River Water

The pollution of our limited natural resources, including surface waters, is a growing problem. The deterioration of the lakes and rivers is that is occurring is caused, in part, by the addition of organic material. One source of this organic pollution is the waste products of man and domestic animals, primarily in the form of fecal material. To control fecal pollution it is necessary to detect it. To detect such pollution quantitative methods are necessary. Methods for the detection of bacterial indicators endogenous to fecal material were developed for this purpose. Therefore, the purpose of this investigation is to determine and compare the survival of selected strains of the fecal coliforms and fecal streptococci in river water. Laboratory studies were conducted under controlled conditions of temperature, aeration, nitrogen etc., to determine the factors of major influence on the survival of fecal coliforms and fecal streptococci in river water. River studies were conducted, using an environmental chamber, to determine and compare the survival of fecal coliforms and fecal streptococci under more natural conditions. Correlation of data from laboratory and field studies were also made. It is the hope that this investigation will better define the value of fecal coliforms and fecal streptococci as indicators of fecal pollution in surface water resources

Prevalence and Proportionality of English Language Learners in Minnesota Special Education

Disproportionality of services to some groups of students in special education is a national problem in the United States due to the risk that students are missed for important intervention services, or students are being pulled from the general education curriculum when they are not in need of extra services. This study consisted of a statistical analysis of the Minnesota Automated Recording Student System data set to determine the extent of disproportionality amongst English-, Spanish-, Hmong-, Somali-, and “Other”- speaking students in each of the 14 special education categorical labels over the academic years 2006-07, 2009-10, and 2012-13. Prevalence rates, percentage change, risk ratios, analysis of variance, and Tukey’s Honest Significant Difference Test were used to determine if differences existed between home language groups in each special education category. Results indicate that, overall, English Language Learning (ELL) students in Minnesota were at risk for underrepresentation compared to English Primary Language students in special education, although there were also instances of overrepresentation in some special education categories for some language groups. There were significant differences in enrollment in 9 of the 14 special education categories (Specific Learning Disability (SLD), Speech-Language Impairment (SLI), Emotional Behavioral Disorder, Other Health Impairment, Developmental Delay, Autism Spectrum Disorder (ASD), Developmental Cognitive Delay Mild, Deaf/Hard of Hearing (D/HH), and Deaf-Blind), with over- and underrepresentation related to interactions between language groups and special education categories. Because SLD, SLI, ASD, and D/HH are special education categories in which students are frequently served by speech-language pathologists (SLPs), these categories were further examined to determine which home language groups in particular were significantly different. The results of this research has implications for special education professionals, education policy makers, and SLPs when serving students from culturally and linguistically diverse backgrounds. More research is needed to determine why disproportionality exists between language groups, if special education enrollment is beneficial for ELL students, and to determine prevalence rates of language groups in other states and within Minnesota school districts

REGENERATIVE STORMWATER CONVEYANCE: TECHNIQUES TO WATERSHED STEWARDSHIP & TURNING STORMWATER LIABILITIES INTO AMENITIES

Regenerative Stormwater Conveyance (RSC) is a moderately new best management practice primarily implemented in the mid-Atlantic region. This thesis documents the proposed design of an RSC at Parkdale High School in the Washington D.C. metropolitan region. A degraded channel with incised banks between 9 to 12 feet in height was found on site. This stormwater channel runs for 160 feet and has a contributing catchment of 17.2 acres. The proposed RSC was designed to stabilize the channel banks, and create a stable channel profile. The runoff storage volume was calculated to be 4523.1 ft3 total which would treat a runoff volume of 0.24”. This equates to 32% TN, 37% TP and 40% TSS removal. The design provides a viewing area with a photo point and bank pin that would provide an opportunity for students and teachers to assist in visually documenting sediment deposition and geomorphological changes that may occur

Creating Novel Antimicrobial Peptides: From Gramicidin A to Screening a Cyclic Peptide Library

Thesis advisor: Jianmin GaoAs the threat of microbial resistance to antibiotics grows, we must turn in new directions to find new drugs effective against resistant infections. Antimicrobial peptides (AMPs) and host-defense peptides (HDPs) are a class of natural products that have been well-studied towards this goal, though very few have found success clinically. However, as there is much known about the behavior of these peptides, work has been done to manipulate their sequences and structures in the search for more drug-like properties. Additionally, novel sequences and structures mimicking those seen in nature have been discovered and characterized. Herein, we demonstrate our ability to finely tune the antimicrobial activity of various peptides, such that they can be provided with more clinically desirable characteristics. Our results show that gramicidin A (gA) can be made to be less toxic via incorporation of unnatural cationic amino acids. This is achieved by synthesizing lysine analogues with diverse hydrophobic groups alkylated to the side-chain amine. Through exploring different groups, we achieved peptide structures with improved selectivity for bacterial over mammalian membranes. Additionally, we were able to achieve novel broad-spectrum gram-negative activity for gA peptides. In efforts to combat bacterial resistance to cationic antimicrobial peptides (CAMPs), we have directed our reported amine-targeting iminoboronate chemistry towards neutralizing Lys-PG in bacterial membranes. Originally incorporating 2-APBA into gA, we found this to hinder the peptide’s activity. However, we were successful in increasing the potency of gA3R, a cationic mutant of gA, towards S. aureus by using a co-treatment of this peptide with a Lys-PG binding structure. Currently, we are exploring this strategy further. Finally, we describe our work towards establishing a novel cyclic peptide library incorporating a 2-APBA warhead for iminoboronate formation with a given target. In this, we have achieved intermolecular reduction of iminoboronates, strengthening the stringency of library screening. Although we were unsuccessful in finding a potent hit for binding of the lipid II stem peptide, screening against human transferrin yielded selective hits. Currently we are investigating these hits to understand their activity and therapeutic potential.Thesis (PhD) — Boston College, 2017.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Chemistry