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- Description:
- : Forests play a major role in the global carbon cycle. Previous studies on the capacity of forests to sequester atmospheric CO2 have mostly focused on carbon uptake, but the roles of carbon turnover time and its spatiotemporal changes remain poorly understood. Here, we used long-term inventory data (1955-2018) from 695 mature forest plots to quantify temporal trends in living vegetation carbon turnover time across tropical, temperate, and cold climate zones, and compared plot data to eight Earth system models (ESMs). Long-term plots consistently showed decreases in living vegetation carbon turnover time, likely driven by increased tree mortality across all major climate zones. Changes in living vegetation carbon turnover time were negatively correlated with CO2 enrichment in both forest plot data and ESM simulations. However, plot-based correlations between living vegetation carbon turnover time and climate drivers such as precipitation and temperature diverged from those of ESM simulations. Our analyses suggest that forest carbon sinks are likely to be constrained by a decrease in living vegetation carbon turnover time, and accurate projections of forest carbon sink dynamics will require an improved representation of tree mortality processes and their sensitivity to climate in ESMs.
- Subject:
- Forestry
- Creator:
- Anderegg, William R.L., Schraub, Marcus, Yu, Kailiang, Gessler, Arthur, Penuelas, Josep, Cailleret, Maxine, Peng, Changhui, Condit, Richard, Ferretti, Marco, Hubbell, Stephen P., Smith, William K., Sardans, Jordi, Levanic, Tom, Zhu, Kai, and Trugman, Anna T.
- Owner:
- KAILIANG YU
- Language:
- English
- Date Uploaded:
- 10/24/2019
- Date Modified:
- 12/09/2021
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/doi:10.7278/S50D-D656-FSP2
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- Description:
- Background: The objective of this study was to evaluate the effect of utilising larger lens cubes on phacoemulsification efficiency and chatter using 3 tips of different sizes and 2 ultrasound (US) approaches. Methods: This was an in vitro laboratory study conducted at the John A. Moran Eye Center Laboratory, University of Utah, Salt Lake City, UT, USA. Porcine lens nuclei were formalin-soaked for 2 hours, then divided into either 2.0 mm or 3.0 mm cubes. 30 degree bent 19 G, 20 G, and 21 G tips were used with a continuous torsional US system; and straight 19 G, 20 G, and 21 G tips were used with a micropulse longitudinal US system. Efficiency and chatter were determined. Results: Mean phacoemulsification removal time was higher with the 3.0 mm lens cube for all US variations and tip sizes. There were statistically significant differences between the 19 G and 21 G tips with micropulse longitudinal US using the 2.0 mm lens cube and the 3.0 mm lens cube, as well as with continuous transversal US using the 2.0 mm lens cube and the 3.0 mm lens cube. There was no significant difference between 19 G and 20 G tips with either lens cube size in either US approach. However, using both US approaches, trends were identical for both lens cube sizes in which the 19 G tips performed better than the 20 G and 21 G tips. Conclusion: Regardless of lens size, the 19 G needle was the most efficient, with the fewest outliers and smallest standard deviations.
- Subject:
- ophthalmology
- Creator:
- Barlow, William R., Bernhisel, Ashlie A., Zaugg, Brian, Olson, Randall J., Ramshekar, Aniket, Heczko, Joshua B., and Pettey, Jeff H.
- Depositor:
- Susan Schulman
- Owner:
- Jeff Pettey
- Based Near Label Tesim:
- Salt Lake City, Utah, United States
- Language:
- English
- Date Uploaded:
- 11/26/2019
- Date Modified:
- 12/09/2021
- Date Created:
- 20180201 - 20180204
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/doi:10.7278/S50D-ZTWP-VF00
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- Description:
- This project was a NSF-funded collaborative research project entitled: Collaborative Research: Deciphering Eolian Paleoenvironmental and Hydrodynamic records: Lower Jurassic Navajo Sandstone, Colorado Plateau, USA This was a multifaceted interdisciplinary study of the Lower Jurassic Navajo Sandstone (Ss)--a unique and distinctive unit in all of geologic history. This unit represents the largest known ancient desert (erg), and is typically classified as a record of a hyperarid environment. Furthermore, the Navajo Ss was deposited at a time when mammals were undergoing their first major diversification, and dinosaurs began to dominate the landscape in number and diversity. Our goal was to examine sedimentary features of the erg margin that recorded the active paleohydrology of the desert regime, and examine abundant trace- and body-fossil material to more fully document the structure and evolution of the biota in a variably arid landscape through Navajo Ss deposition. Field studies involved sedimentology and paleoecology. Laboratory studies involved isotope geochemistry of carbonate deposits, as well as thin section petrography.
- Creator:
- Chan, Marjorie A.
- Owner:
- BRIAN MCBRIDE
- Based Near Label Tesim:
- Moab, Utah, United States
- Language:
- English
- Date Uploaded:
- 07/10/2019
- Date Modified:
- 12/09/2021
- Date Created:
- May 2015-May 2017
- Resource Type:
- Dataset
- Identifier:
- https://doi:10.7278/S50D-D7DX-GJG0
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- Description:
- The dynamic properties of freestanding rock landforms are a function of fundamental material and mechanical parameters, facilitating non-invasive vibration-based structural assessment. Characterization of resonant frequencies, mode shapes, and damping ratios, however, can be challenging at culturally-sensitive geologic features, such as rock arches, where physical access is limited. Using sparse ambient vibration measurements, we describe three resonant modes between 1 and 40 Hz for 17 natural arches in Utah spanning a range of lengths from 3 – 88 m. Modal polarization data are evaluated to combine field observations with 3-D numerical models. We find outcrop-scale elastic moduli vary from 0.8 to 8.0 GPa, correlated with diagenetic processes, and identify low damping at all sites. Dense-array cross-correlation results from an additional arch validate predictions of simple bending modes and fixed boundary conditions. Our results establish use of sparse ambient resonance measurements for structural assessment and monitoring of arches and similar freestanding geologic features.
- Subject:
- geological engineering
- Creator:
- Finnegan, Riley, Moore, Jeffrey R, and Geimer, Paul R
- Owner:
- Paul Geimer
- Based Near Label Tesim:
- Utah, Utah, United States
- Language:
- English
- Date Uploaded:
- 01/13/2020
- Date Modified:
- 12/09/2021
- Date Created:
- 2015-2019
- Resource Type:
- Dataset
-
- Description:
- The Andes Cordillera, which runs the length of South America and rises up to 5,000 m MSL within 200 km of the Pacific coast, dramatically influences the distribution of winter precipitation and snowpack over Chile and Argentina. The study of orographic precipitation processes, particularly along the western slopes of the Andes, is important to improve forecasts of severe flooding and snowpack in a region that depends on snowmelt for water resources. While orographic effects have been investigated on synoptic scales in the Andes, the lack of operational radar coverage and high-elevation, long-term precipitation records have, before the present study, precluded an in-depth investigation into the mesoscale and microphysical processes that affect the distribution of precipitation in the region. This dataset was collected during the Chilean Orographic and Mesoscale Precipitation Study (ChOMPS), which, from May-October 2016, investigated the evolution of precipitation amounts, dropsize distribution, and the vertical profile of radar echoes along an east-west transect that stretched from the Pacific coast to the windward slope of the Andes. The transect, at ~36°S, was made up of a coastal site upstream of the coastal mountain range (Concepción), a central valley site (Chillán), and a mountain site (Las Trancas). Instrumentation along the transect included three vertically pointing Micro-Rain-Radars, two Parsivel Disdrometers, and several meteorological stations. The dataset documents the evolution of Doppler velocity and reflectivity profiles with inland extent during early, middle, and late storm sectors. Additionally, the transect provides a season-long record of the inland evolution of melting layer height as well as the prevalence and structure of shallow non-brightband rain and the characteristics of its inland penetration to the central valley. This dataset, the first of its kind in the Chilean Andes, provides unique insight into mesoscale and orographic precipitation processes that also have applicability to the west coast of the United States and other mountainous regions.
- Subject:
- Meteorology
- Creator:
- Campbell, Leah S., Minder, Justin, and Garreaud, Rene
- Contributor:
- Steenburgh, Jim, Rojas, Yazmina, Viscarra, Also, Montecinos, Aldo, Veloso, Daniel Sebastian, and Salazar, Diego Rivera
- Owner:
- Leahs Campbell
- Based Near Label Tesim:
- Chile, , Chile
- Language:
- English
- Date Uploaded:
- 05/16/2020
- Date Modified:
- 12/09/2021
- Date Created:
- May 15 2016 - October 7 2016
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/doi:10.7278/S50DJXEW0JH3
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- Description:
- Objective: In 2018, the Network of the National Libraries of Medicine (NNLM) launched a national sponsorship program to support U.S. public library staff in completing the Medical Library Association’s (MLA) Consumer Health Information Specialization (CHIS). The primary objective of this research project was to determine if completion of the sponsored specialization was successful in improving public library staff ability to provide consumer health information and whether it resulted in new services, programming, or outreach activities at public libraries. Secondary objectives of this research were to determine motivation for and benefits of the specialization and to determine the impact on sponsorship on obtaining and continuing the specialization. Methods: To evaluate the sponsorship program, we developed and administered a 16-question online survey via REDCap in August 2019 to 224 public library staff that were sponsored during the first year of the program. We measured confidence and competence in providing consumer health information using questions aligned with the eight Core Competencies for Providing Consumer Health Information Services [1]. Additionally, the survey included questions about new consumer health information activities at public libraries, public library staff motivation to obtain the specialization, and whether it led to immediate career gains. To determine the overall value of the NNLM sponsorship, we measured whether funding made it more likely for participants to complete or continue the specialization. Results: Overall, 136 participants (61%) responded to the survey. Our findings indicated that the program was a success: over 80% of participants reported an increase in core consumer health competencies, with a statistically significant improvement in mean competency scores after completing the specialization. Ninety percent of participants have continued their engagement with NNLM, and over half offered new health information programs and services at their public library. All respondents indicated that completing the specialization met their expectations, but few reported immediate career gains. While over half of participants planned to renew the specialization or obtain the more advanced, Level II specialization, 72% indicated they would not continue without the NNLM sponsorship. Conclusion: Findings indicate that NNLM sponsorship of the CHIS specialization was successful in increasing the ability of public library staff to provide health information to their community. and This dataset represents the de-identified raw results of a 16-question, online survey (via REDCap) collected in August 2019 to 224 public library staff who were sponsored for a Consumer Health Information Specialization (CHIS). The purpose of the study was to determine whether the sponsorship program had an impact on public library staff to provide consumer health information.
- Subject:
- Interprofessional Relations, Information Services, Professional Competence, Librarians / education, Libraries, Libraries, Medical , Consumer Health Information, and Humans
- Creator:
- Lake, Erica, Wolfe, Susan M, Knapp, Molly , Spatz, Michele, and Kiscaden, Elizabeth
- Owner:
- Molly Knapp
- Based Near Label Tesim:
- United States, , United States
- Language:
- English
- Date Uploaded:
- 11/12/2020
- Date Modified:
- 02/05/2021
- Date Created:
- August 2019
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50D1DAY2QQQ
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- Description:
- Using a suite of numerical calculations, we consider the long-term evolution of circumbinary debris from the Pluto--Charon giant impact. Initially, these solids have large eccentricity and pericenters near Charon's orbit. On time scales of 100--1000 yr, dynamical interactions with Pluto and Charon lead to the ejection of most solids from the system. As the dynamics moves particles away from the barycenter, collisional damping reduces the orbital eccentricity of many particles. These solids populate a circumbinary disk in the Pluto-Charon orbital plane; a large fraction of this material lies within a `satellite zone' that encompasses the orbits of Styx, Nix, Kerberos, and Hydra. Compared to the narrow rings generated from the debris of a collision between a trans-Neptunian object (TNO) and Charon, disks produced after the giant impact are much more extended and may be a less promising option for producing small circumbinary satellites.
- Subject:
- Astronomy
- Creator:
- Bromley, Benjamin and Kenyon, Scott
- Owner:
- BENJAMIN BROMLEY
- Language:
- English
- Date Uploaded:
- 02/03/2021
- Date Modified:
- 12/09/2021
- Date Created:
- 20191115 to 20200220
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50DSSMBHHXN
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- Description:
- We analyzed 4,754 broadband seismic recordings of the SKS, SKKS, and SPdKS wavefield from 13 high quality events sampling the Samoa ultralow-velocity zone (ULVZ). We measured differential travel-times and amplitudes between the SKKS and SKS arrivals, which are highly sensitive to the emergence of the SPdKS seismic phase, which is in turn highly sensitive to lowermost mantle velocity perturbations such as generated by ULVZs. We modeled these data using a 2-D axi-symmetric waveform modeling approach and are able to explain these data with a single ULVZ. In order to predict both travel-time and amplitude perturbations we found that a large ULVZ length in the great circle arc direction on the order of 10° or larger is required. The large ULVZ length limits acceptable ULVZ elastic parameters. Here we find that δVS and δVP reductions from 20% to 22% and 15% to 17% respectively gives us the best fit, with a thickness of 26 km. Initial 3-D modeling efforts do not recover the extremes in the differential measurements, demonstrating that 3-D effects are important and must be considered in the future. However, the 3-D modeling is generally consistent with the velocity reductions recovered with the 2-D modeling. These velocity reductions are compatible with a compositional component to the ULVZ. Furthermore, geodynamic predictions for a compositional ULVZ that is moving predict a long linear shape similar to the shape of the Samoa ULVZ we confirm in this study. and This collection includes radial component displacement seismograms in the time window including the SKS, SKKS and SPdKS seismic arrivals. These data all interact with the Samoa ultra-low velocity zone at the core-mantle boundary. All data used in the study of Krier et al., 2021 (JGR) is included in this collection.
- Subject:
- Geology, seismology, and Geophysics
- Creator:
- Michael S. Thorne, Tarje Nissen-Meyer, Justin D. Krier, and Kuangdai Leng
- Owner:
- Michael Thorne
- Based Near Label Tesim:
- Tonga Trench, , Tonga
- Language:
- English
- Date Uploaded:
- 02/17/2021
- Date Modified:
- 12/09/2021
- Date Created:
- January 2019 to January 2020
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50DT3X22GGB
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- Description:
- Ground-based measurements of frozen precipitation are heavily influenced by interactions of surface winds with gauge-shield geometry. The Multi-Angle Snowflake Camera (MASC), which photographs hydrometeors in free-fall from three different angles while simultaneously measuring their fall speed, has been used in the field at multiple mid-latitude and polar locations both with and without wind shielding. Here we present an analysis of Arctic field observations — with and without a Belfort double Alter shield — and compare the results to computational fluid dynamics (CFD) simulations of the airflow and corresponding particle trajectories around the unshielded MASC. MASC-measured fall speeds compare well with Ka-band Atmospheric Radiation Measurement (ARM) Zenith Radar (KAZR) mean Doppler velocities only when winds are light (< 5 m/s) and the MASC is shielded. MASC-measured fall speeds that do not match KAZR measured velocities tend to fall below a threshold value that increases approximately linearly with wind speed but is generally < 0.5 m/s. For those events with wind speeds < 1.5 m/s, hydrometeors fall with an orientation angle mode of 12 degrees from the horizontal plane, and large, low-density aggregates are as much as five times more likely to be observed. Simulations in the absence of a wind shield show a separation of flow at the upstream side of the instrument, with an upward velocity component just above the aperture, which decreases the mean particle fall speed by 55% (74%) for a wind speed of 5 m/s (10 m/s). We conclude that accurate MASC observations of the microphysical, orientation, and fall speed characteristics of snow particles require shielding by a double wind fence and restriction of analysis to events where winds are light (< 5 m/s). Hydrometeors do not generally fall in still air, so adjustments to these properties' distributions within natural turbulence remain to be determined.
- Subject:
- Meteorology and Atmospheric Science
- Creator:
- Talaei, Ahmad, Hang, Chaoxun, Fitch, Kyle E., and Garrett, Timothy J.
- Owner:
- Language:
- English
- Date Uploaded:
- 07/20/2020
- Date Modified:
- 12/14/2020
- Date Created:
- 20120521 to 20200719
- Resource Type:
- Software or Program Code
- Identifier:
- https://doi.org/10.7278/S50DQTX9K7QY
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- Description:
- This study investigates impacts of altering subgrid-scale mixing in “convection-permitting” km-scale horizontal grid spacing (∆h) simulations by applying either constant or stochastic multiplicative factors to the horizontal mixing coefficients within the Weather Research and Forecasting model. In quasi-idealized 1-km ∆h simulations of two observationally based squall line cases, constant enhanced mixing produces larger updraft cores that are more dilute at upper levels, weakens the cold pool, rear inflow jet, and front-to-rear flow of the squall line, and degrades the model’s effective resolution. Reducing mixing by a constant multiplicative factor has the opposite effect on all metrics. Completely turning off parameterized horizontal mixing produces bulk updraft statistics and squall line mesoscale structure closest to a LES “benchmark” among all 1-km simulations, although the updraft cores are too undilute. The stochastic mixing scheme, which applies a multiplicative factor to the mixing coefficients that varies stochastically in time and space, is employed at 0.5-, 1-, and 2-km ∆h. It generally reduces mid-level vertical velocities and enhances upper-level vertical velocities compared to simulations using the standard mixing scheme, with more substantial impacts at 1-km and 2-km ∆h compared to 0.5-km. The stochastic scheme also increases updraft dilution to better agree with the LES for one case, but has less impact on the other case. Stochastic mixing acts to weaken the cold pool but without a significant impact on squall line propagation. It also does not affect the model’s overall effective resolution unlike applying constant multiplicative factors to the mixing coefficients.
- Subject:
- Atmospheric Sciences
- Creator:
- Stanford, McKenna, Morrison, Hugh, and Varble, Adam
- Owner:
- MCKENNA STANFORD
- Language:
- English
- Date Uploaded:
- 08/17/2020
- Date Modified:
- 10/27/2020
- Date Created:
- 20190301 - 20200430
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50DJNGQ6V67