Reproductive Effort and Lipid Dynamics of the Emerald Shiner (Notropis atherinoides) in the Upper Niagara River, New York

Life history theory predicts that reproductive characteristics of organisms will be shaped by biotic and abiotic factors to maximize their overall fitness. In this study, I investigated how growth, reproductive effort, and lipid dynamics vary ontogenetically and seasonally for emerald shiners (Notropis atherinoides) in the upper Niagara River. Growth rates were highest in age 2 shiners and lower in age 1 and age 3 individuals. Evidence of reproduction was found beginning at age 1, and reproductive investment as measured by ovarian lipid content was lowest in age 1 and age 2 individuals and greatest in age 3 fish. All age classes exhibited significant changes in somatic lipids across sampling seasons, with minima in spring and maxima in fall. Fulton’s condition factor K did not accurately represent variation in somatic lipid reserves that were found in this study, and therefore this index is not likely to be an accurate measure of overall health and robustness for this species. My findings suggest that emerald shiners exhibit a life history strategy where somatic growth is prioritized over reproduction until their third year of life when large investments into reproduction result in significantly reduced growth rates. Although prior studies have examined growth and reproductive traits of the emerald shiner, my study is the first to document significant changes in lipid dynamics across seasons and age groups in this native keystone species

An improved thin-film microelectrode array and signal conditioning board for measuring cardiac surface potentials.

The work outlined in this thesis expanded on previous work to improve a thin-film microfabricated electrode array intended for cardiac electrophysiology studies. A thin layer of silver was added in between titanium and platinum electrical trace layers to reduce electrode resistance. A 200 nm layer of silver decreased electrode resistance by an order of magnitude. In addition, a new high quality signal conditioning board was developed using precision operational amplifiers from Texas Instruments. Both new sensor and board design were verified together through in vivo studies using rabbit, goat, and dog hearts

Thyr: a volumetric ray-marching tool for simulating microwave emission

Gyrosynchrotron radiation is produced by solar flares, and can be used to infer properties of the accelerated electrons and magnetic field of the flaring region. This microwave emission is highly dependent on many local plasma parameters, and the viewing angle. To correctly interpret observations, detailed simulations of the emission are required. Additionally, gyrosynchrotron emission from the chromosphere has been largely ignored in modelling efforts, and recent studies have shown the importance of thermal emission at millimetric wavelengths. Thyr is a new tool for modelling microwave emission from three-dimensional flaring loops with spatially varying atmosphere and increased resolution in the lower corona and chromosphere. Thyr is modular and open-source, consisting of separate components to compute the thermal and non-thermal microwave emission coefficients and perform three-dimensional radiative transfer (in local thermodynamic equilibrium). The radiative transfer integral is computed by a novel ray-marching technique to efficiently compute the contribution of many volume elements. This technique can also be employed on a variety of astrophysics problems. Herein we present a review of the theory of gyrosynchrotron radiation, and two simulations of identical flare loops in low- and high resolution performed with Thyr, with a spectral imaging analysis of differing regions. The high-resolution simulation presents a spectral hardening at higher frequencies. This hardening originates around the top of the chromosphere due to the strong convergence of the magnetic field, and is not present in previous models due to insufficient resolution. This hardening could be observed with a coordinated flare observation from active radio observatories