Future projections suggest an increase in drought globally with climate change. Current vegetation models typically regulate the plant photosynthetic response to soil moisture stress through an empirical function, rather than a mechanistic response where plant water potentials respond to changes in soil water. This representation of soil moisture stress may introduce significant uncertainty into projections for the terrestrial carbon cycle. We examined the use of the soil moisture limitation function in historical and future emissions scenarios in nine Earth system models. We found that soil moisture-limited productivity across models represented a large and uncertain component of the simulated carbon cycle, comparable to 3-286% of current global productivity. Approximately 40-80% of the intermodel variability was due to the functional form of the limitation equation alone. Our results highlight the importance of implementing mechanistic water limitation schemes in models and illuminate several avenues for improving projections of the land carbon sink.
Micrometer-scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial alteration of oceanic basalt in a low temperature hydrothermal system. An integrative investigative approach uses synchrotron source X-ray microdiffraction (µXRD), microfluoresence (µXRF), micro-computed tomography (µCT), and scanning transmission electron microscopy (S/TEM) coupled with Raman spectroscopy to create finely resolved spatial frameworks that record a continuum of alteration in glass and olivine. Micro-analytical maps of vesicular and fractured lapilli in specimens from 157.1, 137.9, and 102.6 m depth, and borehole temperatures of 83, 93.9 and 141.3 °C measured in 1980, respectively, describe the production of nanocrystalline clay mineral, zeolites, and Al-tobermorite in diverse microenvironments. Irregular alteration fronts at 157.1 m depth resemble microchannels associated with biological activity in older basalts. By contrast, linear microstructures with little resemblance to previously described alteration features have nanocrystalline clay mineral (nontronite) and zeolite (amicite) texture. The crystallographic preferred orientation rotates around an axis parallel to the linear feature. Raman spectra indicating degraded and poorly-ordered carbonaceous matter of possible biological origin are associated with nanocrystalline clay mineral in a crystallographically-oriented linear microstructure in altered olivine at 102.6 m and with sub-circular nanoscale cavities in altered glass at 137.9 m depth. Although evidence for biotic processes is inconclusive, the integrated analyses describe the complex organization of previously unrecognized mineral texture in very young basalt. They provide a foundational mineralogical reference for longitudinal, time-lapse characterizations of palagonitized basalt in oceanic environments.
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1. Description of methods used for collection/generation of data: The data were generated by computer simulations using the C++ code "Orchestra", a proprietary hybrid code that follows the dynamical evolution of solids and gas orbiting a central object. Algorithms in the code are described in the following papers (author names abbreviated to B for Bromley, K for Kenyon, and L for Jane X Luu along with a year for publication date, AJ = Astronomical Journal, ApJ = Astrophysical Journal, S=Supplement): KL1998, AJ 115:2136; KL1999, AJ 118:1101; KB2001,AJ 121:538; KB2002,AJ 123:1757; KB2004, AJ 127:513; BK2006, AJ 131:2737; KB2006, AJ 131:1837; KB2008, ApJS 179:451; KB2010, ApJS 188:242; BK2011, ApJ 731:101; KB2012, AJ 143:63; KB2014, AJ 147:8. Initial conditions for these simulations described in the published paper.
2. Methods for processing the data: Various C and fortran programs are used to analyze the data for the calculations. Several C programs needed to extract information from the computer generated binary output files are included with the dataset. The C programs include basic summaries of the structure of the data files and the usage to extract data from each binary file.
3. Instrument- or software-specific information needed to interpret the data: Appropriate software is included in directory.
4. Standards and calibration information, if appropriate: none
5. Environmental/experimental conditions: all calculations were run on the NASA discover cluster
6. Describe any quality-assurance procedures performed on the data: Aside from tests summarized in the papers described in item 1, test calculations are summarized in the Appendix of each paper and compared to an appropriate benchmark.
7. People involved with sample collection, processing, analysis and/or submission: Scott Kenyon and Ben Bromley and --------------------- DATA & FILE OVERVIEW ---------------------
Files summarized in items 1-8 are binary output files from n-body simulations as described in Kenyon & Bromley, "A Pluto-Charon Sonata: Dynamical Limits on fate Masses of the Small Satellites" (2019, Astronomical Journal). Files described in item 9 are ascii txt. The C programs in items 10, 11, and 12 provide different ways to access the binary output. Each C program describes the architecture of the binary files.
1. pcs2-0mmm-nnn[a-z] files: heavy satellites, mmm = 100 x mass factor for all satellites, nnn = number of Symplectic steps per PC orbit, a-z = version
2. pcs2-1mmm-nnn[a-z] files: light satellites, mmm = 100 x mass factor for all satellites, nnn = number of Symplectic steps per PC orbit, a-z = version
3. pcs2-2mmm-nnn[a-z] files: light satellites with 2x nominal mass of Styx & Kerberos, mmm = 100 x mass factor for all satellites, nnn = number of Symplectic steps per PC orbit, a-z = version
4. pcs2-3mmm: heavy satellites, 40 Symplectic steps per PC orbit, mmm = 100 x mass factor for Nix only
5. pcs2-4mmm: heavy satellites, 40 Symplectic steps per PC orbit, mmm = 100 x mass factor for Kerberos only
6. pcs2-5mmm: heavy satellites, 40 Symplectic steps per PC orbit, mmm = 100 x mass factor for Hydra only
7. pcs2-6mmm light satellites, 40 Symplectic steps per PC orbit, mmm = 100 x mass factor for Nix only
8. pcs2-7mmm: light satellites, 40 Symplectic steps per PC orbit, mmm = 100 x mass factor for Hydra only
9. pcs2-n000.dat: summary of lifetimes for binary files in each archive 10. lifetime.c: summarizes lifetime and mass factor for binary file usage example: "lifetime pcs2-6110"
11. summary.c: generates basic summary of timesteps in a binary file usage example: "summary pcs1-0013d"
12. extrxyz.c: extracts (x,y,z) for N satellites and outputs (x,y,z) usage example: "extr6d pcs1-6110 6" will output (x,y,z) for SNKH 3. Additional related data collected that was not included in the current data package: There are other binary output files not included in this archive. 4. Are there multiple versions of the dataset? no
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.
The widely documented phenomenon of nighttime stomatal conductance (gsn) could lead to substantial water loss with no carbon gain, and thus it remains unclear whether nighttime stomatal conductance confers a functional advantage. Given that studies of gsn have focused on controlled environments or small numbers of species in natural environments, a broad phylogenetic and biogeographic context could provide insights into potential adaptive benefits of gsn. • We measured gsn on a diverse suite of species (n = 73) across various functional groups and climates-of-origin in a common garden to study the phylogenetic and biogeographic/climatic controls on gsn and further assessed the degree to which gsn co-varied with leaf functional traits and daytime gas exchange rates. • Closely related species were more similar in gsn than expected by chance. Herbaceous species had higher gsn than woody species. Species that typically grow in climates with lower mean annual precipitation – where the fitness cost of water loss should be the highest – generally had higher gsn. • Our results reveal the highest gsn rates in species from environments where neighboring plants compete most strongly for water, suggesting a possible role for the competitive advantage of gsn.
The mechanisms governing tree drought mortality and recovery remain a subject of inquiry and active debate given their role in the terrestrial carbon cycle and their concomitant impact on climate change. Counter-intuitively, many trees do not die during the drought itself. Indeed, observations globally have documented that trees often grow for several years after drought before mortality. A combination of meta-analysis and tree physiological models demonstrate that optimal carbon allocation after drought explains observed patterns of delayed tree mortality and provides a predictive recovery framework. Specifically, post-drought, trees attempt to repair water transport tissue and achieve positive carbon balance through regrowing drought-damaged xylem. Further, the number of years of xylem regrowth required to recover function increases with tree size, explaining why drought mortality increases with size. These results indicate that tree resilience to drought-kill may increase in the future, provided that CO2 fertilization facilitates more rapid xylem regrowth.
Background. Common cold viruses create significant health and financial burdens, and understanding key loci of transmission would help focus control strategies. This study (1) examines factors that influence when individuals transition from a negative to positive test (acquisition) or a positive to negative test (loss) of rhinovirus (HRV) and other respiratory tract viruses in 26 households followed weekly for one year, (2) investigates evidence for intrahousehold and interhousehold transmission and the characteristics of individuals implicated in transmission, and (3) builds data-based simulation models to identify factors that most strongly affect patterns of prevalence. Methods. We detected HRV, coronavirus, paramyxovirus, influenza and bocavirus with the FilmArray polymerase chain reaction (PCR) platform (BioFire Diagnostics, LLC). We used logistic regression to find covariates affecting acquisition or loss of HRV including demographic characteristics of individuals, their household, their current infection status, and prevalence within their household and across the population. We apply generalized linear mixed models to test robustness of results. Results. Acquisition of HRV was less probable in older individuals and those infected with a coronavirus, and higher with a higher proportion of other household members infected. Loss of HRV is reduced with a higher proportion of other household members infected. Within households, only children and symptomatic individuals show evidence for transmission, while between households only a higher number of infected older children (ages 5-19) increases the probability of acquisition. Coronaviruses, paramyxoviruses and bocavirus also show evidence of intrahousehold transmission. Simulations show that age-dependent susceptibility and transmission have the largest effects on mean HRV prevalence. Conclusions. Children are most likely to acquire and most likely to transmit HRV both within and between households, with infectiousness concentrated in symptomatic children. Simulations predict that the spread of HRV and other respiratory tract viruses can be reduced but not eliminated by practices within the home.
This SAS program can be used to calculate Grocery Purchase Quality Index-2016 (GPQI-2016) total and component scores from food purchase data (dollars and cents) that have been summarized into the 29 categories of the USDA Food Plans. The code can be adapted to calculate GPQI-2016 scores for data that use a smaller number of categories.