Life Sciences Commons^™

Modeling Post-Fire Successional Trajectories Under Climate Change In Interior Alaska Using Landis Ii, Shelby A. Weiss

Systems Science Friday Noon Seminar Series

Alaska boreal forest ecosystems are experiencing a greater frequency of wildfire relative to the region’s historic fire regime. These increases in fire frequency, as well as annual burned area, increase the probability of forests re-burning within shorter intervals than were experienced historically. Such changes to the fire regime have the potential to shift successional trajectories in this ecosystem. To better understand potential changes in vegetation composition following short-interval, repeat fires, we are using LANDIS-II, a forest landscape model, to simulate changes in forest composition in response to climate change and increasing fire frequency. This seminar will include a description of …

Statistical Analysis Of Social Network Change, Teresa D. Schmidt

Systems Science Friday Noon Seminar Series

We explore two statistical methods that infer social network structures and statistically test those structures for change over time: regression-based differential network analysis (R-DNA) and information theory-based differential network analysis (I-DNA). RDNA is adapted from bioinformatics and I-DNA employs reconstructability analysis. Both methods are used to analyze Medicaid claims data from one-year periods before and after the formation of the Health Share of Oregon Coordinated Care Organization (CCO). We hypothesized that Health Share’s CCO formation would be followed by several changes in the healthcare delivery network.

Application of R-DNA and I-DNA to claims data involves three steps: (a) the inference …

Interview With Ted Lorensen, Ted Lorensen, Lloyd Chapman, James B. Knight, Michael Rupp

People and the Land: An Oral History of Oregon’s Statewide Land Use Planning Program

Ted Lorensen was interviewed by Michael Rupp, Lloyd Chapman, and Jim Knight on October 20, 2017, in Portland, Oregon.

Neural Coding And Decoding, Alexander Dimitrov

Systems Science Friday Noon Seminar Series

Methods based on Rate Distortion theory have been successfully used to cluster stimuli and neural responses in order to study neural codes at a level of detail supported by the amount of available data. They approximate the joint stimulus-response distribution by quantizing paired stimulus-response observations into smaller reproductions of the stimulus and response spaces. An optimal quantization is found by maximizing an information-theoretic cost function subject to both equality and inequality constraints, in hundreds to thousands of dimensions. This analytical approach has several advantages over other current approaches:

• it yields the most informative approximation of the encoding scheme given the …

Efficient Encoding Of Vocalizations In The Auditory Midbrain, Lars Andreas Holmstrom

Systems Science Friday Noon Seminar Series

An important question in sensory neuroscience is what coding strategies and mechanisms are used by the brain to detect and discriminate among behaviorally relevant stimuli. To address the noisy response properties of individual neurons, sensory systems often utilize broadly tuned neurons with overlapping receptive fields at the system's periphery, resulting in homogeneous responses among neighboring populations of neurons. It has been hypothesized that progressive response heterogeneity in ascending sensory pathways is evidence of an efficient encoding strategy that minimizes the redundancy of the peripheral neural code and maximizes information throughput for higher level processing. This hypothesis has been partly supported …

The Complexity-Independence Of The Origin Of Life, Radu Popa

Systems Science Friday Noon Seminar Series

It is often stated that the macroevolution of life is driven toward increased Complexity, and indeed, biosystems situated at higher evolutionary level show higher levels of Complexity. Yet, evidence also shows that some dynamic systems evolve toward lower entropy states, and not by increasing Complexity, but by increasing Organization. Organization is a parameter with two almost orthogonal components: Order and Complexity. Hence, it is possible for a dynamic system to experience changes in Organization in ways that do not elicit changes in Complexity. Whether Order or Complexity controls changes in Organization is dictated by the capacity of a system to …