School of Graduate Studies and Research
http://hdl.handle.net/20.500.12090/274
Graduate Studies and Research offers a diverse array of 16 master’s and five doctoral degree programs across four academic colleges.2020-01-23T17:13:54ZMicroelectrode electrode array studies of spinal motor neurons
http://hdl.handle.net/20.500.12090/532
Microelectrode electrode array studies of spinal motor neurons
Tharaneetharan, Arumugarajah
Co-cultures are a traditional method for studying the cellular properties of cell to cell interactions among different cell types. How network properties in these multicellular synthetic systems vary from monocultures are of particular interest. Understanding the changes in the functional output of these in vitro spiking neural networks can provide new insights into in vivo systems and how to develop biological system models that better reflect physiological conditions - something of paramount importance to the progress of synthetic biology. Culture models of spinal motor neurons have been customarily studied as a monoculture, and the overwhelming consensus is that in culture they are different in nature from their in vivo counterparts. I studied the electrophysiological properties of spinal ventral horn networks cocultured with myocytes or astrocytes using a 64 channel microelectrode array system to record extracellular voltage measurements. When compared over a period of 40 days, significant differences were found between coculture types in metrics of spiking, bursting, and network bursting. Myocyte cocultures, when compared with simple ventral horn cultures, showed significant decreases in spikes, spike amplitudes, spike energy, number of units in network burst, and an increase in interspike interval. Astrocyte cocultures, when compared with simple ventral horn cultures showed decreases in sorted units, burst duration, mean interspike interval, and network burst duration but increases in spikes, energy of spikes, bursts, spikes per burst, network bursts, and number of units per network burst. This suggests that traditional culturing techniques involving a uniform cell type might not be the best way to functionally model in vivo neural networks. Concerning an in vitro model system for lower motor neurons, the most accurate model would most likely be a combination of spinal motor neurons cultured with myocytes as well as increased levels of astrocytes. A synthetic ecosystem of various cell types is beneficial to replicating cell behavior in vitro, thus is a necessary refinement to the commonly used technique of cell culture. With a more physiological model system, hypotheses about interacting systems can be better addressed and the outcomes will have greater relevancy.
Numerical determination of scattering and bound states via self-consistent field theory
http://hdl.handle.net/20.500.12090/531
Numerical determination of scattering and bound states via self-consistent field theory
Tyler, Micah Danielle
Interpretation of atomic spectra and the applications of atomic spectroscopy to current problems in astrophysics, laser physics, and thermonuclear plasma require a precise knowledge of atomic structure and dynamics. The collisional excitation and ionization of atomic targets by electron impact is distinct in that one or more electrons are in the continua, which makes the theory complicated and also drastically disturbs the system for probing and detection.
Analysis of interacting atomic systems is complex and many approximate methods have been developed in the past. The most prominent of these methods is the Hartree-Fock procedure and its relativistic and multiconfiguration extensions. This self-consistent-field (SCF) approach has been limited to treating only fully bound, negative energy states whose corresponding wave functions are square-integrable. Recently, the SCF extension to scattering in which continuum (positive-energy) states are involved, has been formulated. The non-integrability of the continuum functions can be overcome by an amputation procedure that retains all of the physical essentials of the scattering system. It is extended here to the electron-hydrogenic scattering system in the zero angular momentum coupling models. In this project, the focus is on devising a numerical algorithm for solving such systems of integro-differential equations stemming from the SCF theory. The method is compared with results obtained by several other approaches. It is shown that the newly devised numerical approach converges as the amputated continuum functions provide an effective projection of the scattering function.
An Evaluation of a Northern Bobwhite (Colinus virginianus) Parent-reared Release in South Carolina
http://hdl.handle.net/20.500.12090/530
An Evaluation of a Northern Bobwhite (Colinus virginianus) Parent-reared Release in South Carolina
Haley, Ryan
Northern bobwhites (Colinus virginianus) have experienced large, range-wide declines mainly attributed to the loss of early-successional habitat. Bobwhite population recovery is predicated on sound habitat management. Even when adequate habitat exists, low bobwhite densities and limited dispersal capabilities may limit population recovery. Restocking techniques, including release of pen-reared birds, wild bobwhite translocation, and the use of wild-strained, parent-reared captive-raised bobwhites have been explored as surrogates to natural recolonization. In this study, I evaluated survival and reproduction of parent-reared bobwhites, compared to resident bobwhites, on a private property in South Carolina from April 2009-April 2013. I used a sequential modeling approach to evaluate adult survival and nest survival using Program MARK. Bobwhite survival was best explained by temporal (annual and weekly) effects and group (parent-reared vs. resident) effects. Weekly bobwhite survival for both parent-reared and resident bobwhites was too low to produce a stable population. Parent-reared bobwhite survival was lower than resident bobwhites during the first 3 weeks post-release but similar during later weeks. Parent-reared bobwhites released in August had higher survival (S = 0.884, 95% CI = 0.862, 0.903) than birds released in early fall (S = 0.707, 95% CI = 0.621, 0.782). Nest survival and other reproductive parameters for parent-reared and resident bobwhite were similar. The viability of the parent-reared release system as a restocking technique is limited as currently constructed and future modification is needed if it is to produce a viable bobwhite population
A Study on the Numerical and Analytical Solutions of Complex-Variable Partial Differential Equations
http://hdl.handle.net/20.500.12090/529
A Study on the Numerical and Analytical Solutions of Complex-Variable Partial Differential Equations
Moore, Matthew Neil
In this work, we consider the analogue of a real-variable partial differential equation. In comparison to what has already been thoroughly investigated, recall the non-linear Schrodinger equation (NLSE). The NLSE, which is used in determining the wave equation for quantum particles, is a real-variable PDE with complex coefficients. Instead, we consider equations where both the function $\omega$ and its independent variable $z$ belong to the complex plane. We approach the complex problem by an intuitive approach of treating a one-complex variable differential equation as a two-real variable partial differential equation by analyzing the real and imaginary parts of both $\omega$ and $z$. We investigate thoroughly the first-order complex PDE case and prove the existence and uniqueness theorem for these types of equations. We also investigate the analytical solutions by considering the complex-variable Laplace transform, which can be thought of in parallel as a two-variable Laplace transform with in $\mathbb{R}^2$. Upon completion of the first-order case, we consider the higher order complex-variable PDE. We discuss both the direct way of solving higher-order equations via systems of real-variable PDE’s and also via first-order systems of complex-variable PDE’s, in which we implement the methods of the previous topics. As a direct consequence of the higher-order differential equation solution method, we also discuss an alternative method of evaluating complex contour integrals via a real-variable partial differential equation evaluation. To conclude, we consider the time-dependent complex variable PDE analogues of the advection and wave equations, we briefly discuss multi-complex variable PDE’s and methods that we plan to investigate in the near future.