Fall 2015 Student Seminars

The WISeNet Student Seminars are held during the fall semester and presented by current WISeNet students.  These seminars provide students the opportunity to share their research or to discuss their experience at one of the WISeNet laboratory or field experiment sites with other WISeNet participants.

 

October 6, 2015 Daniel Pages
   
October 20, 2015

Christopher Krapu

   
November 3, 2015 John Mallard
 

 

November 17, 2015 John Gardner
   

Daniel Pages

Tuesday, October 6, 2015; 330 Gross Hall - noon to 1:00 p.m.

 Department: Psychology and Neuroscience

 IGERT WISeNet Trainee: 2014 - 2016

  "Effect of Inferior Colliculus Microstimulation on Frequency Perception in Nonhuman Primates"

Abstract: Understanding the relationship between auditory response properties of neurons and the contribution of their activity to perception is critical to the design of effective auditory brain prosthetics. These prosthetics seek to mimic natural activity patterns to achieve desired perceptual outcomes. The inferior colliculus (IC) has been proposed as a possible site for patients who cannot benefit from existing auditory prosthetics in the cochlea. In order to understand the perceptual outcome of IC stimulation, we trained monkeys to report their auditory perception in a frequency discrimination task in which the animal had to decide which of two sounds was higher in frequency. Microstimulation pulses at different sites in the IC were paired with one of the two sounds on 50% of trials in the frequency discrimination task. We found widespread perceptual effects of IC microstimulation that increased with increasing current (e.g. 54% of experiments showing systematic effects when tested at 80 µA). Furthermore, the perceptual shifts induced by microstimulation correlated significantly with the frequency tuning of the neurons at the electrode site, supporting the view that stimulation of the IC can provide predictable percepts via site of activation in the IC. 

 


Christopher Krapu

Tuesday, October 20, 2015; 330 Gross Hall - noon to 1:00 p.m.

 Department: Environmental Sciences & Policy

 IGERT WISeNet Trainee: 2014 - 2016

 Optimal Groundwater and Soil Moisture Sensor Placement for Estimation of Event Streamflow

Given that streamflow response at the watershed outlet is a function of soil moisture and groundwater dynamics within the watershed, it is reasonable to hypothesize that observations of groundwater and soil moisture can be used to estimate event streamflow. We investigate this hypothesis by using spatially-distributed groundwater and soil moisture time series generated by a physics-based hydrologic model, PIHM. In the absence of data from an intensely observed real watershed, the simulated time series are considered as a surrogate for observed data in this analyses. Next, we identify the optimal locations for groundwater and soil moisture observation for estimating the magnitude of quickflow events. Results indicate that even in a large watershed with heterogeneous land cover and soil properties, nearly 90% of the variance in event quickflow can be explained with measurements of antecedent and in-event soil conditions.  Close examination of the identified sites show that soil properties and topography of the modeled system allows for general, practical rules to enhance the accuracy of streamflow estimation via groundwater wells and soil moisture sensors. 


 

 

John Mallard

Tuesday, November 3, 2015; 330 Gross Hall - noon to 1:00 p.m.

 Department: NSOE - Earth & Ocean Sciences

 IGERT WISeNet Trainee: 2014 - 2016

The Evolving Understanding of Southern Piedmont Watershed Hydrology as Seen Through the Lens of the Calhoun Critical Zone Observatory: Hypotheses, Sensor Network, and Observations

The Calhoun Experimental Forest unit of the Sumter National Forest in upstate South Carolina represents regionally typical convergence of historic agricultural use and subsequent land abandonment with a location in rapidly growing region (the Southern Piedmont of the United States). With the recent creation of the Calhoun Critical Zone Observatory (CCZO) we are presented with a unique opportunity to understand the hydrology of this physically unique system (characterized by deep soil profiles, highly variable topography, and a significantly dissected drainage pattern) with an important historic legacy (massive sheet and gully erosion forced by intensive commodity agricultural). As one piece of this story we present initial hypotheses about the functional effects of the topographic and pedological structure of the CCZO as currently understood, the sensor network deployed to address these hypotheses, and some results from a growing set of field data streams collected at the CCZO.


John Gardner

Tuesday, November 17 2015; 330 Gross Hall - noon to 1:00 p.m.

 Department: Nicholas School of Environmental Science

 IGERT WISeNet Trainee: 2014 - 2016

 Optimal Groundwater and Soil Moisture Sensor Placement for estimation of Event Streamflow

Flowing waters are dynamic environments and how we sense them impacts our understanding of connecting pattern with process. This is particularly important when inferring ecosystem level processes from simple water quality measurements, for example estimating metabolism from dissolved oxygen. In order to better interpret process from pattern, multiple references frames of measurement can be deployed. The reference frames described here are stationary (Eulerian), passively moving (Lagrangian), and a spatial snap shot (synoptic) and they have been combined into a conceptual and methodological framework for sensing aquatic systems. However, the Lagrangian reference frame is rarely applied in inland waters and a field methodology is lacking; therefore, a sensing platform designed for rivers was developed. The Lagrangian sensing unit, known as the Hydrosphere (Planktos Instruments Inc.), along with data from all three reference frames will be presented to discuss the effect of water movement and heterogeneity within a river channel on ecosystem function using the example of aquatic ecosystem metabolism.