Prior work suggests that complementary white matter pathways within the hippocampus (HPC) differentially support the learning of specific versus general information. In particular, while the trisynaptic pathway (TSP) rapidly forms memories for specific experiences, the monosynaptic pathway (MSP) slowly learns generalities.However, despite the theorized significance of such circuitry, characterizing how information flows within the HPC to support learning in humans remains a challenge.We leveraged diffusion-weighted imaging as a proxy for individual differences in white matter structure linking key regions along with TSP (HPC subfields CA 3 and CA 1 ) and MSP (entorhinal cortex and CA 1 ) and related these differences in hippocampal structure to category learning ability. We hypothesized that learning to categorize the "exception" items that deviated from category rules would benefit from TSPsupported mnemonic specificity. Participant-level estimates of TSP-and MSP-related integrity were constructed from HPC subfield connectomes of white matter streamline density. Consistent with theories of TSP-supported learning mechanisms, we found a specific association between the integrity of CA 3 -CA 1 white matter connections and exception learning. These results highlight the significant role of HPC circuitry in complex human learning.

Prior work suggests that complementary white matter pathways within the hippocampus differentially support learning of specific versus general information. In particular, while the trisynaptic pathway (TSP) rapidly forms memories for specific experiences, the monosynaptic pathway (MSP) slowly learns generalities. However, despite the theorized significance of such circuitry, characterizing how information flows within hippocampus (HPC) to support learning in humans remains a challenge. We leveraged diffusion-weighted imaging as a proxy for individual differences in TSP and MSP white matter structure and related it to category learning ability. We hypothesized that learning to categorize the "exception" items that deviated from category rules would benefit from TSP-supported mnemonic specificity. Participant-level estimates of TSP and MSP integrity were constructed from HPC subfield connectomes of white matter streamline density. Consistent with theories of TSP-supported learning mechanisms, we found a specific association between TSP integrity and exception learning. These results highlight the significant role of HPC circuitry in complex human learning.

In the last decade, hydraulic fracturing has rapidly gained popularity worldwide, emerging as the leading method of natural gas extraction in the United States. However, the practice remains controversial due to its contribution to greenhouse gas emissions and the contamination of freshwater used in fracturing fluids. Although waterless fracturing fluids have been developed, including those using N2, CO2, oil, and alcohol, their application has been limited largely due to reduced fracturing power. Recent research has demonstrated that cryogenic nitrogen may prove a viable alternative, if this issue is properly addressed. Addition of durable, lightweight proppants is one way to increase fracturing power. This study aims to investigate the effect of proppant addition on the fracturing capabilities of cryogenic nitrogen. Three ultra-lightweight proppants will be combined with liquid nitrogen and fracturing power will be measured using triaxial stress tests. This novel approach has not yet been explored and will open more avenues of research into sustainable and efficient fracturing using  cryogenic nitrogen.

Introduction: Hydraulic fracturing has rapidly gained popularity in the last decade, emerging as the leading method of natural gas extraction in the United States. The practice remains controversial, however, due to the release of greenhouse gases from burning shale gas as well as the contamination of freshwater used in fracturing fluids. Although waterless fracturing fluids have been developed, including nitrogen, carbon dioxide, oil, and alcohol, their application has been limited due to either reduced fracturing power or safety, as well as environmental concerns. Recent research suggests that cryogenic liquid nitrogen may provide both a safe and environmentally-friendly alternative if a number of additional characteristics of its fracturing capabilities can be improved. Addition of ultra-lightweight proppants is a potential method of increasing the fracturing power of less viscous fluids. This research protocol aims to investigate the effect of ultra-lightweight proppant addition on the fracturing capabilities of liquid nitrogen. Methods: Three ultra-lightweight proppants will be combined at differing concentrations with liquid nitrogen and applied to samples of shale rock under triaxial stress. A control trial will also apply liquid nitrogen without the addition of any proppant. Fracturing power, measured on the basis of fracture length, will be assessed following each trial. Results:The results of these triaxial stress tests will provide measures of fracturing power for each proppant type and concentration combination. Discussion: Analysis of these results will reveal whether the addition of ultra-lightweight proppants increases the fracturing capabilities of liquid nitrogen as well as identify the proppant type and concentration combination that affords liquid nitrogen the greatest fracturing power. Conclusion: The effect of ultra-lightweight proppant addition on the fracturing capabilities of liquid nitrogen has yet to be explored. Implementation of this protocol will open more avenues of research into sustainable and efficient fracturing using liquid nitrogen. Note:The authors of this article were invited by the URNCST Journal to publish this conference proceeding as a result of presenting a winning abstract at the Scinapse 2017-2018 Undergraduate Science Case Competition. A complete collection of abstracts presented at this conference was published by the URNCST Journal in March 2018 and can be found here: https://doi.org/10.26685/urncst.47.