42 research outputs found

    Observations and modeling of a hydrothermal plume in Yellowstone Lake

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    Author Posting. © American Geophysical Union, 20XX. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(12), (2019): 6435-6442, doi:10.1029/2019GL082523.Acoustic Doppler current profiler and conductivity‐temperature‐depth data acquired in Yellowstone Lake reveal the presence of a buoyant plume above the “Deep Hole” hydrothermal system, located southeast of Stevenson Island. Distributed venting in the ~200 × 200‐m hydrothermal field creates a plume with vertical velocities of ~10 cm/s in the mid‐water column. Salinity profiles indicate that during the period of strong summer stratification the plume rises to a neutral buoyancy horizon at ~45‐m depth, corresponding to a ~70‐m rise height, where it generates an anomaly of ~5% (−0.0014 psu) relative to background lake water. We simulate the plume with a numerical model and find that a heat flux of 28 MW reproduces the salinity and vertical velocity observations, corresponding to a mass flux of 1.4 × 103 kg/s. When observational uncertainties are considered, the heat flux could range between 20 to 50 MW.The authors thank Yellowstone National Park Fisheries and Aquatic Sciences, The Global Foundation for Ocean Exploration, and Paul Fucile for logistical support. This research was supported by the National Science Foundation grants EAR‐1516361 to R. S., EAR‐1514865 to K. L., and EAR‐1515283 to R. H. and J. F. All work in Yellowstone National Park was completed under an authorized Yellowstone research permit (YELL‐2018‐SCI‐7018). CTD and ADCP profiles reported in this paper are available through the Marine Geoscience Data System (doi:10.1594/IEDA/324713 and doi:10.1594/IEDA/324712, accessed last on 17 April 2019, respectively).2019-11-0

    Autonomous Tennis Ball Collector

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    Practicing tennis often involves hitting many tennis balls from one side of the court to the other without an opponent to hit the balls back. In training sessions like these, the task of collecting the balls is laborious when performed manually. The objective of this project is to develop a robotic tennis ball collector that can automatically collect the balls from one side of the court so that the player can rest rather than collect the balls manually. This document outlines the process of designing such a robot. Included in this report is background research, prototype, and concept modeling, along with a finalized design, and a complete timeline of our process. We will also detail the manufacturing process and the design verification. In the conclusion we will provide you with recommendations for future projects. Throughout our research, we discovered many similar products, but none met all of the customer’s requirements, thus opening a window for our product. After copious design consideration, we selected the strongest idea that satisfied our customers’ needs and are moving forward with structural modeling and preliminary analysis on it. After the structural prototype revealed issues in the design we went back to work and finalized a design that we felt confident with and still satisfied all the requirements. As seen in this report the final design utilizes structural framing materials to build the robot and allows for ease of attachment for all the electrical components. The final step in the design process was to test the verification prototype to ensure that it met all our specifications. Unfortunately, our design did not pass as many of the tests as we would have liked, and this is detailed in that section. While at the conclusion of this project, we did not complete as much as we hoped, there is a good foundation in place for the project to continue as our sponsor so desires

    Receptor Heteromerization Expands the Repertoire of Cannabinoid Signaling in Rodent Neurons

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    A fundamental question in G protein coupled receptor biology is how a single ligand acting at a specific receptor is able to induce a range of signaling that results in a variety of physiological responses. We focused on Type 1 cannabinoid receptor (CB1R) as a model GPCR involved in a variety of processes spanning from analgesia and euphoria to neuronal development, survival and differentiation. We examined receptor dimerization as a possible mechanism underlying expanded signaling responses by a single ligand and focused on interactions between CB1R and delta opioid receptor (DOR). Using co-immunoprecipitation assays as well as analysis of changes in receptor subcellular localization upon co-expression, we show that CB1R and DOR form receptor heteromers. We find that heteromerization affects receptor signaling since the potency of the CB1R ligand to stimulate G-protein activity is increased in the absence of DOR, suggesting that the decrease in CB1R activity in the presence of DOR could, at least in part, be due to heteromerization. We also find that the decrease in activity is associated with enhanced PLC-dependent recruitment of arrestin3 to the CB1R-DOR complex, suggesting that interaction with DOR enhances arrestin-mediated CB1R desensitization. Additionally, presence of DOR facilitates signaling via a new CB1R-mediated anti-apoptotic pathway leading to enhanced neuronal survival. Taken together, these results support a role for CB1R-DOR heteromerization in diversification of endocannabinoid signaling and highlight the importance of heteromer-directed signal trafficking in enhancing the repertoire of GPCR signaling

    A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

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    dentification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 x 10(-8)) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.Peer reviewe

    Heat flux from a vapor-dominated hydrothermal field beneath Yellowstone Lake

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    Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(5),(2021): e2020JB021098, https://doi.org/10.1029/2020JB021098.We report results from 149 heat flux measurements made over an ∌2-year interval at sites in and around a vapor-dominated geothermal field located at water depths of ∌100–120 m in Yellowstone Lake, Wyoming. Measurements of both in situ temperature and thermal conductivity as a function of depth were made with a 1 m probe via a remotely operated vehicle, and are combined to compute the vertical conductive heat flux. Inside the ∌55.5 × 103 m2 bathymetric depression demarcating the vapor-dominated field, the median conductive flux is 13 W m−2, with a conductive output of 0.72 MW. Outside the thermal field, the median conductive flux is 3.5 W m−2. We observed 49 active vents inside the thermal field, with an estimated mass discharge rate of 56 kg s−1, a median exit-fluid temperature of 132°C, and a total heat output of 29 MW. We find evidence for relatively weak secondary convection with a total output of 0.09 MW in thermal area lake floor sediments. Our data indicate that vapor beneath the thermal field is trapped by a low-permeability cap at a temperature of ∌189°C and a depth of ∌15 m below the lake floor. The thermal output of the Deep Hole is among the highest of any vapor-dominated field in Yellowstone, due in part to the high boiling temperatures associated with the elevated lake floor pressures.This work was funded by U.S. National Science Foundation (NSF) grants EAR-1515283 to R. N. Harris and J. E. Favorito, EAR-1516361 to R. A. Sohn, and EAR-1514865 to K. M. Luttrell All work in Yellowstone National Park was completed under research permit (YELL-2018-SCI-7018) and the authors thank Annie Carlson from the Yellowstone Center for Resources for logistical help.2021-11-1
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