Nitrogen (N) is one of the vital elements for potato production. As well as common synthetic fertilizers, turkey manure compost (TMC) is more commonly used as a source of N for potato production in Minnesota. The aim of this study was to compare traditional N sources and applications (urea broadcast, Environmentally Smart Nitrogen (ESN) broadcast, and ESN banded at hilling) to TMC broadcast prior to planting on yield and quality of Russet Burbank in Minnesota. The TMC treatment resulted in a similar marketable yield compared to the urea and ESN treatments. The TMC also increased the percentage of the >170 g tuber yield. French fry color quality was not affected by N treatment in either year. The TMC was a good nitrogen source that is readily available and provides a good sustainable option for potato production. Further work should examine what benefits conventional fertilizer can have when used with TMC.

The earth's gravity field G * at a point P in the region surrounding the earth's surface is defined as the force acting on a unit mass concentrated at P. This is a force resulting from two components: (1) G1 due to the gravitational attraction of the earth's mass, and (2) G2 due to the earth's rotation.

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I have developed a technique to solve for the khronon field in a space-time containing a slowly moving black hole in the khrono-metric regime of Hořava Gravity. To develop these solutions I first revisited the khronon field around static spherically symmetric black holes and perturbed them by a small velocity. The equations of motions of the perturbed field were identified along with the linearly dependent series expansions at the boundary points. Using the boundary conditions and equations of motion the khronon field was numerically solved throughout the space-time. These solutions were used to calculate a sensitivity parameter which defines how the black hole mass appears to be modified due to its velocity. It was found that the sensitivity parameters are highly suppressed and black holes should appear similar to their general relativity counterpart. / Thesis / Master of Science (MSc) / I have investigated slowly moving black holes in a theory of modified gravity. The goal was to see whether the theory breaks down in modelling these black holes and if not, is it possible to test the theory using these predictions. I ultimately found that this theory can model the slowly moving black holes and would appear almost indistinguishable from classically moving black holes. This means that slowly moving black holes on their own will not provide a sufficient test of the theory.

This paper empirically examines the effect of institutional quality on trade considering the gravity equation model. Taking data for 252 countries covering the period of 19 years from 1996 to 2014, the research has been done with two stage regression analysis. In the first stage, we estimate the effect of gravity factors that either benefit or hinder trade along with OECD membership and Linder’s effect by Poisson-Pseudo-Maximum-Likelihood (PPML) estimator with importer- time, and exporter- time fixed effects. Taking the estimated exporter- time fixed effects from the first stage, we regress it with institutional variables in the second stage by OLS method with country and time fixed effects. Results indicate that institutional quality has a significant and positive impact on bilateral export with mostly 1% and 5% significance level. Interestingly, our study also shows that Linder’s effect is negative only for trade among the OCED countries.

The work of this thesis is guided by the Analogue Gravity research programme, in which condensed matter systems are used as analogues of the physics of curved spacetimes to obtain new perspectives on open problems of gravitational physics. Here we use this idea to investigate the phenomenon of superradiance, most famously occurring in rotating black hole spacetimes, using as an analogue system atomic Bose-Einstein condensates (BECs). Superradiance is a radiation enhancement phenomenon in which waves of different kind are scattered with an increased amplitude by extracting energy from the object they are scattering on. In this thesis on the one hand we use the gravitational analogy to understand better superradiance starting from easier analogue setups, and on the other hand we use concepts coming from superradiance to learn something about the physics of BECs. We first present a (possibly realizable) toy model, built using the tools of synthetic gauge fields for neutral atoms, to provide a new and conceptually simple illustration of superradiant scattering. This toy model allows to disentangle the different elements at play and highlight the basic mechanisms of superradiance and has also the interesting feature of being exactly mappable to a scattering problem of a charged scalar field on an electrostatic potential. We also show how at the quantum level, superradiance implies the spontaneous emission of pairs of excitations. The low temperatures of atomic condensates can make these quantum features visible and we propose a way of detecting them via correlation measurements. Another realization of this toy model can also be built using periodic trapping potentials for the atoms. By changing the boundary conditions of the acoustic excitations of the condensate we show how superradiance can give rise to dynamical instabilities. Our toy model gives a simple illustration of superradiant instabilities occurring in rotating gravitational spacetimes, in particular ergoregion instabilities and black hole bombs. It also provides a realization of the analogous instabilities involving a charged scalar field, called the Schiff-Snyder-Weinberg effect. Our approach naturally shows how amplified scattering can also occur in the presence of dynamical instabilities, a point often object of confusion in the literature. Moreover, we add an acoustic horizon to our toy model and show that, differently from what happens in general relativity, horizons do not always prevent the presence of ergoregion instabilities. We then apply these concepts to the study of the stability of quantized vortices in two-dimensional BECs. With a careful account of boundary conditions, we show that the dynamical instability of multiply quantized vortices in trapped condensates persists in untrapped, spatially homogeneous geometries and has an ergoregion nature with some modification due to the peculiar dispersion of Bogoliubov sound. Our results open new perspectives to the physics of vortices in trapped condensates, where multiply quantized vortices can be stabilized by interference effects and singly charged vortices can become unstable in suitably designed trap potentials. We show how superradiant scattering can be observed also in the short-time dynamics of dynamically unstable systems, providing an alternative point of view on dynamical (in)stability phenomena in spatially finite systems. Finally we consider the equivalent of a shear layer between parallel flows in hydrodynamics, but in a BEC. In the present case the shear layer is constituted by and array of quantized vortices that are shown to develop an instability analogous to the Kelvin-Helmholtz instability. When the relative velocity between the two parallel flow is sufficiently large however, this instability is quenched and substituted by a slower instability that has the features of the superradiant instabilities we studied. Differently from superradiant instabilities, this one also remains with open boundary conditions on the two sides of the shear layer, and manifests itself as a continuous emission of phonons in both directions; we call this new regime radiative instability.

The human risk as a spatial component using Newton?s Gravity model is explored for the first time in this research along with fuels and road density variables to predict the fire occurrences for Southeast Mississippi fire district. The fire risk map indicated that fires occur in clusters and are dependent on fire size and distance from roads. The results proved that fire size increases as fire locations increase. Fire locations decrease significantly beyond 160 meters with increasing road distance. The Gravity model proved to be a better estimator of fire risk while a similar road density model proved to be better in very low and medium fire risk zones. Compared to road density, the gravity model significantly proved a better estimate of very low fire risk for all seasons and summer low fire risk. For all other fire risks, though, gravity model showed better results no significant differences were observed.

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