A review of the research indicates that identifying self as a teacher can be a life-long, complex personal and social process. This researcher investigated 4 pre-collegiate students' construction of a teaching identity during their participation in an introduction to teaching course conducted in a rural high school located in a southeastern state. Two purposes framed this investigation, 1) to gain an in-depth understanding of the pre-collegiate students' past and present experiences related to teaching and the meanings the students make of these experiences, and 2) to examine these experiences as connected to construction of personal teaching identities. Using a life history methodology, data sources included 3 interviews, drawings of self as a teacher, journal writings, and personal experience writings. The findings are presented in 4 narratives one for each participant. Each narrative, represented by an exemplar quote, (i.e., Being There, Being a Kid, Right Heart, Being A Helper) illuminates the nature of the participants' teaching prototype, which emerged from past and present educational experiences. Results indicate that the participants possessed well-defined beliefs pertaining to caring teachers and to teaching as a profession, in addition, to commonly held cultural teaching beliefs. These beliefs guided their course experiences and self-assessment of a teaching identity. Although the identification to a teaching identity varied among the 4 participants, results indicate that 1 participant was actively constructing a storied teaching identity. A storied teaching identity involved a significant nuclear episode with a teacher that became the bound context for a teaching story. This type of high school level career studies course can assist in strengthening the recruitment pool of teacher education candidates and assist in testing a vocational teaching identity. Implications are offered for future research involving pre-collegiate students enrolled in an introduction to teaching course and investigation of storied teaching identities. / Ph. D.

In this work, we present different deep learning-based digital pre-distorters and compare them based on their performance towards improving the linearity of highly non-linear power amplifiers. The simulation results show that BiLSTM based DPDs work the best in terms of improving the linearity performance. We also compare two methodologies of direct learning and indirect learning to develop deep learning-based digital pre-distorters (DL-DPDs) models and evaluate their improvement on the linearity of Power Amplifiers (PA). We carry out a theoretical analysis on the differences between these training methodologies and verify their performance with simulation results on class-AB and class-F⁻¹ PAs. The simulation results show that both the learning methods lead to an improvement of more than 12 dB and 11dB in the linearity of class-AB and class-F⁻¹ PAs respectively, with indirect learning DL-DPD offering marginally better performance. Moreover, we compare the DL-DPD with memory polynomial models and show that using the former gives a significant improvement over the memory polynomials. Furthermore, we discuss the advantages of exploiting a BiLSTM based neural network architecture for designing direct/indirect DPDs. We demonstrate that BiLSTM DPD can be used to pre distort signals of any size without the drop in linearity. Moreover, based on the insights we develop a frequency domain loss using which further increased the linearity of the PA. / Master of Science / Wireless communication devices have fundamentally changed the way we interact with people. This increased the user's reliance on communication devices and significantly grew the need for higher data rates and faster internet speeds. But one major obstacle inside the transmitter chain (antenna) with increasing the data rates is the power amplifier, which distorts the signals at these higher powers. This distortion will reduce the efficiency and reliability of communication systems, greatly decreasing the quality of communication. So, we developed a high-performance DPD using deep learning to combat this issue. In this paper, we compare different deep learning-based DPDs and analyze which offers better performance. We also contrast two training methodologies to learn these DL-DPDs, theoretically and with simulation to arrive at which method offers better performing DPDs. We do these experiments on two different types of power amplifiers, and signals of any length. We design a new loss function, such that optimizing it leads to better DL-DPDs.

In fiber optic communication systems, the main linear phenomenon that causes optical pulse broadening is called dispersion, which limits the transmission data rate and distance. The principle nonlinear effect, called self-phase modulation, can also limit the system performance by causing spectral broadening. Hence, to achieve the optimal system performance, high data rate and low bandwidth occupancy, those effects must be overcome or compensated. In a nonlinear dispersive fiber, properties of a transmitting pulse: width, chirp, and spectra, are changed along the way and are complicated to predict. Although there is a well-known differential equation, called the Nonlinear Schrodinger Equation, which describes the complex envelope of the optical pulse subject to the nonlinear and dispersion effects, the equation cannot generally be solved in closed form. Although, the split-step Fourier method can be used to numerically determine pulse properties from this nonlinear equation, numerical results are time consuming to obtain and provide limited insight into functional relationships and how to design input pulses. One technique, called the Variational Method, is an approximate but accurate way to solve the nonlinear Schrodinger equation in closed form. This method is exploited throughout this thesis to study the pulse properties in a nonlinear dispersive fiber, and to explore ways to compensate dispersion for both single link and concatenated link systems. In a single link system, dispersion compensation can be achieved by appropriately pre-chirping the input pulse. In this thesis, the variational method is then used to calculate the optimal values of pre-chirping, in which: (i) the initial pulse and spectral width are restored at the output, (ii) output pulse width is minimized, (iii) the output pulse is transform limited, and (iv) the output time-bandwidth product is minimized. For a concatenated link system, the variational calculation is used to (i) show the symmetry of pulse width around the chirp-free point in the plot of pulse width versus distance, (ii) find the optimal dispersion constant of the dispersion compensation fiber in the nonlinear dispersive regime, and (iii) suggest the dispersion maps for two and four link systems in which initial conditions (or parameters) are restored at the output end. The accuracy of the variational approximation is confirmed by split-step Fourier simulation throughout this thesis. In addition, the comparisons show that the accuracy of the variational method improves as the nonlinear effects become small. / Master of Science

Thesis (M.S.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2999-01-01

Vascular endothelial growth factor A (VEGF) is a potent mediator of blood vessel formation throughout the body. Intraocular diseases characterized by inflammation, hypoxia or neoplasia induce new blood vessel formation within the eye. The end result of such blood vessel formation may be blinding sequellae such as glaucoma from outflow obstruction or hyphema from intraocular hemorrhage. Elevated VEGF concentrations in the aqueous humor and vitreous are documented in a number of human intraocular disease processes, including tumors, retinal detachment and uveitic glaucoma. Pharmacotherapy inhibiting VEGF expression demonstrates promise for control of some of these ophthalmic conditions. We quantified and compared VEGF concentrations in canine aqueous humor samples from 13 dogs with normal eyes and 226 eyes from 178 dogs with a variety of ophthalmic diseases by ELISA. Dogs with primary cataract, diabetic cataract, primary glaucoma, uveitic glaucoma, aphakic/pseudophakic glaucoma, retinal detachment, lens luxation and neoplasia were evaluated. Elevated VEGF concentrations were found in all disease conditions tested as compared to normal dogs excepting cataracts and diabetic cataracts. Elevated aqueous humor VEGF concentrations were found in dogs with pre-iridal fibrovascular membranes (PIFM) as compared to dogs without PIFM. These results are consistent with the hypothesis that VEGF has a role in the causation or progression of a variety of canine ocular disorders. / Master of Science

The southern pine beetle (SPB) poses a significant threat to pine forests of the southeastern US. Pre-commercial thinning (PCT) is a commonly used silvicultural practice to mitigate and prevent SPB spread in young southern pine stands. Typically, PCT represents an added management cost to landowners and thinned material is not utilized for forest products. Increased demand for woody biomass energy may provide landowners and harvesting contractors an opportunity to utilize PCT residues as a woody biomass energy feedstock, which may wholly or partially offset PCT costs. However, little information is available regarding harvestable biomass quantities in PCT stands and few studies have assessed harvesting productivity and costs in very young pine stands. To develop estimates of biomass abundance in PCT candidate stands, loblolly pine (Pinus taeda) stands aging 5 to 12-years old, and enrolled in the Virginia Department of Forestry Pine Bark Beetle Prevention Program (VDOF PBBPP), were inventoried across the Piedmont and Coastal Plain regions of Virginia. To attain productivity and cost estimates of utilizing small-diameter stems for woody biomass energy, a biomass harvesting case study was then conducted on a 15-year old loblolly pine stand. Results of the inventory and case study indicate that stands at the upper age limit for the PCT program may contain harvestable quantities of biomass (39.63 green tons/acre), although high harvesting costs ($23.46/green ton) relative to regional delivered biomass prices may limit the economic feasibility of utilizing PCT biomass for energy. / Master of Science

Abstract Gardner's ( I983) Theory of Multiple Intelligences supports developmentally appropriate practice (DAP) espoused by NAEYC for early chiJdhood classrooms. This research examines teachers' use of multiple intelligences-based (MI-based) strategies while teaching for mastery of the required Florida's Sunshine State Standards (SSS). Second grade teachers in a rural community in Central Florida were surveyed with follow-up interviews regarding their teaching practices and philosophies. Data collected show that teachers believe children can master SSS using MI-based strategies but report barriers of large class sizes. Teachers who received training on Ml reported greater success with MI strategies. Teachers reported more use of MI-based strategies for teaching than in their assessment practices. Discussion includes the impact of the state standardized assessments.

Family literacy encompasses the way family members use literacy at home and in their community. This study reports early literacy activities these families do that are connected to the activities they carry out in their every day events. Reading aloud, print awareness, and how reading environmental print relates to young children between the ages of birth to preschool are some of the activities discussed in this study. Other topics such as the time of day parents read to their children and what kind of educational toys or materials their children prefer to use in relation to literacy are also incorporated. A survey instrument was given to parents and is included in Appendix A. The findings reported include the percentages of factors the surveyed parents chose as important to them in regards to early literacy activities and future success in school. Promoting literacy activities at home and in the community is an important role for parents who have children in day care. The purpose of this study was to determine what parents with children in day care do with their preschool children to support literacy development. The research question was How do parents of preschool children attending day care promote literacy activities at home? Seventy-five families that have their children in four different day care centers, participated in this study. The survey instrument used in this study revealed which activities that support literacy are most important to parents that have their children in local day care centers. Of the seventy-five families surveyed, twenty nine families have children that attend day care centers run by the United Cerebral Palsy (UCP) organization. These child development centers serve all children, especially children that have a variety of disabilities. Another forty-six families have children that attend different day care centers in the Apopka area.

Animal behavior can be used to detect disease and well-being in dairy cattle. In this dissertation, we evaluated the accuracy of an accelerometer to measure step activity, lying time, and lying bouts in pre-weaned dairy calves. The output from the accelerometer was correlated with behavioral measurements taken from video footage. The accelerometer proved to be accurate in identifying step activity (r = 0.99), lying time (r = 0.99), and lying bouts (r = 0.99). The accelerometer was then used to detect behavioral changes occurring around respiratory disease events in pre-weaned calves. Activity declined 1 d prior to clinical disease onset, and this decline persisted for 3 d post-diagnosis. Furthermore, lying bouts declined beginning 2 d prior to diagnosis, and this effect persisted after diagnosis as well. However, aside from a slight reduction in milk intake, feeding behavior was not different between diseased and healthy calves. These data suggest that activity and lying behaviors may be a better measure than feeding behaviors for detection of respiratory disease in pre-weaned dairy calves. Dystocia has detrimental effects on both periparturient dairy cows and newborn calves. We administered a non-steroidal anti-inflammatory drug, meloxicam to periparturient dairy cattle. Treatments included administration prior to calving (MEL-PRE, n = 60), post-calving (MEL-POST, n = 69), or a negative control (CTL, n = 65). We measured the length of labor to determine which cows had easy or difficult calvings. Eutocic MEL-PRE animals produced 6.8 kg/d more milk than eutocic CTL. Regardless of calving difficulty, MEL-PRE animals produced more milk fat, protein, and lactose (kg/d) than the CTL. Additional research is needed to determine appropriate treatments for dystocic calvings. Calves born during the above trial were monitored to determine if meloxicam administration prior to calving impacted newborn calf health and behavior. Calves born difficultly displayed fewer lying bouts for the first few days after birth when compared to calves born easily. No effect of treatment or calving difficulty was noted on calf health. Additional research examining intervention strategies aimed at improving well-being of calves born difficultly is needed. / Ph. D. / Public interest in animal welfare continues to grow, making it increasingly important that the dairy industry evaluates management practices to further advance animal well-being. Animal behavior can be used to detect disease and well-being in dairy cattle. We monitored activity and lying behaviors around respiratory disease events in calves. This was done to determine which behaviors were altered by respiratory disease, and if these behaviors could be used to detect respiratory disease events earlier. Activity and lying behaviors were measured using an accelerometer that works similarly to a pedometer. We were able to identify that calves that would manifest with respiratory disease would display a decline in activity prior to clinical disease diagnosis. These data suggest that activity measures could be a promising indicator for respiratory disease detection in calves, and allow for earlier detection. Parturition, the act of a dairy cow giving birth, is a stressful, risky time period as disease incidences and death are high. Furthermore, an immense amount of inflammation occurs after calving due to parturition as well as metabolic stress associated with milk production. Therefore, in this study, we administered a non-steroidal anti-inflammatory drug (meloxicam) to alleviate inflammation. Treatments included administration prior to calving (MEL-PRE), post-calving (MEL-POST), or a negative control (CTL). We measured the length of labor to determine which cows had easy or difficult calving events. Animals that received meloxicam prior to calving and calved easily produced 6.8 kg/d more milk than CTL animals that calved easily. Additional research is needed to determine appropriate treatments for animals that calve difficultly. Calves born during the above trial were monitored to determine if meloxicam administration prior to calving impacted newborn calf health and behavior. No effect of treatment or calving difficulty was noted on calf health. Additional research examining intervention strategies aimed at improving well-being of calves born difficultly is needed.

No / Ab initio calculations, combined with experimental studies on the anaerobic hydrolysis of phosphaalkynes under thermal and photochemical conditions suggest a potential, exogenous source of reduced oxidation state phosphorus for the early Earth.