Exciton-magnon effects in the optical spectrum of MnF2

Exciton and magnon absorption, emission spectra, and fluorescence of antiferromagnetic manganese fluorid

Calcium-Rich Gap Transients: Tidal Detonations of White Dwarfs?

We hypothesize that at least some of the recently discovered class of calcium-rich gap transients are tidal detonation events of white dwarfs (WDs) by black holes (BHs) or possibly neutron stars. We show that the properties of the calcium-rich gap transients agree well with the predictions of the tidal detonation model. Under the predictions of this model, we use a follow-up X-ray observation of one of these transients, SN 2012hn, to place weak upper limits on the detonator mass of this system that include all intermediate-mass BHs (IMBHs). As these transients are preferentially in the stellar haloes of galaxies, we discuss the possibility that these transients are tidal detonations of WDs caused by random flyby encounters with IMBHs in dwarf galaxies or globular clusters. This possibility has been already suggested in the literature but without connection to the calcium-rich gap transients. In order for the random flyby cross-section to be high enough, these events would have to be occurring inside these dense stellar associations. However, there is a lack of evidence for IMBHs in these systems, and recent observations have ruled out all but the very faintest dwarf galaxies and globular clusters for a few of these transients. Another possibility is that these are tidal detonations caused by three-body interactions, where a WD is perturbed toward the detonator in isolated multiple star systems. We highlight a number of ways this could occur, even in lower-mass systems with stellar-mass BHs or neutron stars. Finally, we outline several new observational tests of this scenario, which are feasible with current instrumentation.Comment: 10 pages, 1 figure, accepted for publication in MNRA

Single-Calf Heifer System Profitability Compared to Other North Dakota Beef Production Systems

Production Economics, Productivity Analysis,

A Journey of Pregnancy Loss: From Positivism to Autoethnography

When a dissertation research project exploring the impact of mind - body practices on symptoms of depression and anxiety in pregnant women with a history of miscarriage failed to yield statistically significant results, I struggled with how to demonstrate that I had gleaned knowledge from this project of nearly 3 years. When a series of parallel pregnancy losses occurred in my own life, I realized that I am heavily situated within the context of my research and need to consider my data in a different sense; one that acknowledges my own self within this process while attempting to capture the lived experiences of others. The shift to autoethnography afforded me the opportunity to demonstrate that knowledge can be generated through multiple methodologies, with one approach not being privileged over another. As this dissertation moved from an empirical study to a qualitative, autoethnographic piece, I was able to identify themes surfacing from the literature, my own experiences and participation in a pregnancy loss support group. The themes discussed include: making meaning from the experience, granting personhood status and grieving and other emotional expression

Economics of Establishing a Beef Cattle Feedlot Using By-Products of Ethanol Production in North Dakota

Production Economics, Resource /Energy Economics and Policy, Agribusiness,

Ultrahigh Bandwidth Spin Noise Spectroscopy: Detection of Large g-Factor Fluctuations in Highly n-Doped GaAs

We advance all optical spin noise spectroscopy (SNS) in semiconductors to detection bandwidths of several hundred gigahertz by employing an ingenious scheme of pulse trains from ultrafast laser oscillators as an optical probe. The ultrafast SNS technique avoids the need for optical pumping and enables nearly perturbation free measurements of extremely short spin dephasing times. We employ the technique to highly n-doped bulk GaAs where magnetic field dependent measurements show unexpected large g-factor fluctuations. Calculations suggest that such large g-factor fluctuations do not necessarily result from extrinsic sample variations but are intrinsically present in every doped semiconductor due to the stochastic nature of the dopant distribution.Comment: 5 pages, 3 figure

Sustainable Agriculture and the Structure of North Dakota Agriculture

Environmental Economics and Policy, Industrial Organization, Production Economics,

Ion-lithium collision dynamics studied with an in-ring MOTReMi

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi', is a combination of a magneto-optical trap (MOT) and a Reaction Microscope (ReMi). Operated in an ion-storage ring, the new setup enables to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In first experiments on collisions with 1.5 MeV/amu O$^{8+}$-Li the pure ionization of the valence electron as well as ionization-excitation of the lithium target has been investigated