A new approach to barrier-top fission dynamics

We proposed a calculational framework for describing induced fission that avoids the Bohr-Wheeler assumption of well-defined fission channels. The building blocks of our approach are configurations that form a discrete, orthogonal basis and can be characterized by both energy and shape. The dynamics is to be determined by interaction matrix elements between the states rather than by a Hill-Wheeler construction of a collective coordinate. Within our approach, several simple limits can be seen: diffusion; quantized conductance; and ordinary decay through channels. The specific proposal for the discrete basis is to use the $K^\pi$ quantum numbers of the axially symmetric Hartree-Fock approximation to generate the configurations. Fission paths would be determined by hopping from configuration to configuration via the residual interaction. We show as an example the configurations needed to describe a fictitious fission decay $^{32}{\rm S} \rightarrow ^{16}{\rm O} + ^{16}{\rm O}$. We also examine the geometry of the path for fission of $^{236}$U, measuring distances by the number of jumps needed to go to a new $K^\pi$ partition.Comment: Write-up of a talk given at the Workshop "Compound-nuclear reactions 2015" Tokyo, Oct. 19-23, 2015; 11 pages and 11 figures. To be published in European Journal of Physics, Web of Conference

MEASURING POLITICAL POLARIZATION IN MASS PUBLICS: THE CLUSTER-POLARIZATION COEFFICIENT

Political polarization has become a key concern in many important topics within comparative politics, yet past research has reached little consensus as to its substantive causes and effects. Much of this disagreement, I argue, stems from the use of diverse measurement strategies that do not reliably capture the two key dynamics of polarization: distance and concentration. I use unsupervised machine learning methods to derive the cluster-polarization coefficient (CPC), a novel measurement strategy that scales to high-dimensional analysis and accepts a wide variety of data structures. I use Monte Carlo simulations to show that the CPC predicts polarization with substantially greater accuracy than current measures and I offer a substantive application by replicating and extending the well-known work of DiMaggio, Evans, and Bryson (1996) using data from the American National Election Studies.Master of Art

Multi-Task Learning Improves Performance In Deep Argument Mining Models

The successful analysis of argumentative techniques from user-generated text is central to many downstream tasks such as political and market analysis. Recent argument mining tools use state-of-the-art deep learning methods to extract and annotate argumentative techniques from various online text corpora, however each task is treated as separate and different bespoke models are fine-tuned for each dataset. We show that different argument mining tasks share common semantic and logical structure by implementing a multi-task approach to argument mining that achieves better performance than state-of-the-art methods for the same problems. Our model builds a shared representation of the input text that is common to all tasks and exploits similarities between tasks in order to further boost performance via parameter-sharing. Our results are important for argument mining as they show that different tasks share substantial similarities and suggest a holistic approach to the extraction of argumentative techniques from text

Magnetic Reconnection and The Extreme Plasmas of Blazar Jets

Magnetic reconnection is a plasma physical process in which a magnetic field is topologically rearranged, releasing free energy and imparting it to plasma matter. Though seemingly ubiquitous as a magnetic energy conversion channel in laboratory, space, and astrophysical settings, magnetic reconnection is by no means the same in these diverse environments. Astrophysical reconnection, in particular, is quite different from the type that occurs in the solar system. This difference stems from several unique and extreme properties of astrophysical plasmas. While plasmas on Earth and in nearby space are often non-relativistic, made of electrons and ions (e.g., protons), and non-radiative, astrophysical plasmas are quite frequently relativistic (in both the special and general senses), made of electron-positron pairs, and highly radiative &ndash; exhibiting non-trivial radiation-matter (e.g., QED) interactions. In this dissertation, I focus on radiative relativistic reconnection regimes that prominently feature many of the above extreme effects. Here, the initial magnetic energy per particle exceeds the electron rest mass, enabling reconnection to accelerate relativistic particles. These particles go on to suffer strong radiative losses, emitting photons that may later be absorbed inside the system to produce pairs. Feedback from both direct radiative cooling and pair production contributes to a rich collective interplay between reconnection and high-energy radiative physics. Throughout this work, I treat reconnection as an idealized physical process without explicit reference to many aspects of the global astrophysical environments where it unfolds. Instead, I obtain astrophysical relevance through the relativistic and radiative physics and through the parameter space that I explore. These mimic reconnection conditions in blazar jets &ndash; collimated relativistic outflows from active galactic nuclei traveling toward the observer. Adopting a simplified microphysical perspective enables me to model the plasma (including radiation) with high fidelity and from first principles, especially in the large portion of this work based on numerical simulations. In addition to revealing the nature and observable features of reconnection in blazar jets, the resulting insight sometimes actually constrains the global features of the jet itself, illustrating the utility of a bottom-up, physics-first approach.</p

Stanford Airport Beacon, Judith Basin County

Robert Peccia & Associates presented the Carroll College Engineering Design Class an opportunity to perform the engineering design for a replacement airport beacon for Judith Basin County Airport. The project is in Stanford, Montana. We have been asked to provide engineering for replacement of the current beacon, which is supported by a traditional lattice structure with a Tip-down style beacon. The current beacon has exceeded its design life and is no longer serviceable. Our current design calls for either removing the current beacon and placing the new one in the same location or finding a new location near the airport. Currently, the State Historical Preservation Office is evaluating the historical significance of the existing beacon and, therefore, removal of the current structure may not be possible. We are proceeding with our design with the assumption that SHPO will ultimately allow removal and replacement which will allow us to complete our design within the timeline of our senior design course. We selected a tip-down beacon for its lower cost, and lower maintenance difficulty due to the airport manager being a volunteer who lives locally. The smaller profile of the Tip-Down beacon discourages birds from landing and creating nests on the beacon, the reduced waste from birds will reduce maintenance as well. Other than birds there is not much else for environmental factors within this project. It will take only 1-2 weeks of construction for this process to be completed so that part will not take long. We will have the beacon sit on a 10 foot by 10 foot concrete slab on the edge of airport property. While using our cost estimation for the project, we will contact potential subcontractors that have done projects like this before, evaluating those who will do the job for the best price as well as their capability of providing a quality product

Insulin-Secreting Pancreatic (Islet Cell) Carcinoma in a Cat

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72904/1/j.1939-1676.1992.tb00336.x.pd