Soil respiration (Rs), the soil‐to‐atmosphere CO2 flux produced by microbes and plant roots, is a critical but uncertain component of the global carbon cycle. Our current understanding of the ...variability and dynamics is limited by the coarse spatial resolution of existing estimates. We predicted annual Rs and associated uncertainty across the world at 1‐km resolution using a quantile regression forest algorithm trained with observations from the global Soil Respiration Database spanning from 1961 to 2011. This model yielded a global annual Rs estimate of 87.9 Pg C/year with an associated global uncertainty of 18.6 (mean absolute error) and 40.4 (root mean square error) Pg C/year. The estimated annual heterotrophic respiration (Rh), derived from empirical relationships with Rs, was 49.7 Pg C/year over the same period. Predicted Rs rates and associated uncertainty varied widely across vegetation types, with the greatest predicted rates of Rs in evergreen broadleaf forests (accounting for 20.9% of global Rs). The greatest prediction uncertainties were in northern latitudes and arid to semiarid ecosystems, suggesting that these areas should be targeted in future measurement campaigns. This study provides predictions of Rs (and associated prediction uncertainty) at unprecedentedly high spatial resolution across the globe that could help constrain local‐to‐global process‐based models. Furthermore, it provides insights into the large variability of Rs and Rh across vegetation classes and identifies regions and vegetation types with poor model performance that should be prioritized for future data collection.
Plain Language Summary
Soils emit large amounts of carbon dioxide to the atmosphere every year via the process of soil respiration, which greatly exceeds emissions from human sources. However, rates of soil respiration are highly variable in space, which limits our ability to balance global carbon budgets and forecast climate change. We used a novel application of a machine learning approach to predict annual rates of soil respiration at high resolution (1 km) across the globe and examined spatial patterns of the associated uncertainty of these predictions. Predictions were made based on how observations of soil respiration were related to climate (annual temperature and annual and seasonal precipitation) and vegetation information. Predicted annual soil respiration and prediction uncertainty varied across ecosystem types and regions. Our predictions suggest that evergreen tropical forests dominate global annual soil respiration emissions. Dryland, wetland, and cold ecosystems had the highest associated prediction uncertainties, suggesting that future soil respiration measurements would be especially useful in these areas. The high spatial resolution of our predictions will help researchers studying the carbon cycle at local to global scales.
Key Points
A high spatial resolution machine learning approach was used for estimating soil respiration across the world
Predictions of soil respiration varied widely across ecosystem classes, and allowed for suitable estimates of heterotrophic respiration
Associated prediction uncertainty was highest in high latitudes and data scarce regions, which should be targets for future measurements
Genetic parameters were estimated for a range of meat quality traits recorded on Australian lamb meat. Data were collected from Merino and crossbred progeny of Merino, terminal and maternal meat ...breed sires of the Information Nucleus programme. Lambs born between 2007 and 2010 (n=8968) were slaughtered, these being the progeny of 372 sires and 5309 dams. Meat quality traits were found generally to be of moderate heritability (estimates between 0.15 and 0.30 for measures of meat tenderness, meat colour, polyunsaturated fat content, mineral content and muscle oxidative capacity), with notable exceptions of intramuscular fat (0.48), ultimate pH (0.08) and fresh meat colour a* (0.08) and b* (0.10) values. Genetic correlations between hot carcass weight and the meat quality traits were low. The genetic correlation between intramuscular fat and shear force was high (−0.62). Several measures of meat quality (fresh meat redness, retail meat redness, retail oxy/met value and iron content) appear to have potential for inclusion in meat sheep breeding objectives.
•Genetic parameters were estimated among a range of meat quality traits in lamb meat.•Moderate heritability of many traits showed that they can be altered via selection.•Selection to improve IMF or tenderness associated with reduced meat colour stability•Meat redness and iron content could possibly be included in sheep breeding programmes.
Background: Intravesical chemotherapy (i.e., placement of the drug directly in the bladder) with mitomycin C is beneficial for patients with superficial bladder cancer who are at high risk of ...recurrence, but standard therapy is empirically based and patient response rates have been variable, in part because of inadequate drug delivery. We carried out a prospective, two-arm, randomized, multi-institutional phase III trial to test whether enhancing the drug's concentration in urine would improve its efficacy. Methods: Patients with histologically proven transitional cell carcinoma and at high risk for recurrence were eligible for the trial. Patients in the optimized-treatment arm (n = 119) received a 40-mg dose of mitomycin C, pharmacokinetic manipulations to increase drug concentration by decreasing urine volume, and urine alkalinization to stabilize the drug. Patients in the standard-treatment arm (n = 111) received a 20-mg dose without pharmacokinetic manipulations or urine alkalinization. Both treatments were given weekly for 6 weeks. Primary endpoints were recurrence and time to recurrence. Treatment outcome was examined by use of Kaplan–Meier analysis with log-rank tests. Statistical tests were two-sided. Results: Patients in the two arms did not differ in demographics or history of intravesical therapy. Dysuria occurred more frequently in the optimized arm but did not lead to more frequent treatment termination. In an intent-to-treat analysis, patients in the optimized arm showed a longer median time to recurrence (29.1 months; 95% confidence interval CI = 14.0 to 44.2 months) and a greater recurrence-free fraction (41.0%; 95% CI = 30.9% to 51.1%) at 5 years than patients in the standard arm (11.8 months; 95% CI = 7.2 to 16.4 months) and 24.6% (95% CI = 14.9% to 34.3%) (P = .005, log-rank test for time to recurrence). Improvements were found in all risk groups defined by tumor stage, grade, focality, and recurrence. Conclusions: This study identified a pharmacologically optimized intravesical mitomycin C treatment with statistically significantly enhanced efficacy.
The longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, derived from various breed types, were used to investigate the effect of animal/muscle factors, packaging type ...over-wrap (OW) or high oxygen modified atmosphere packaging (MAPO2) and duration of display on redness of meat during simulated retail display. Using statistical models the time required (in days) for redness to reach a threshold value of 3.5 (below this is unacceptable) was predicted. High levels of iron in the SM, but not LL, reduced the time for redness to reach 3.5 by 2–2.6days in MAPO2 and 0.5–0.8days in OW. The greater the proportion of Merino breed type, the shorter was the time for redness to reach the value of 3.5, an effect consistent across muscles and packaging types. In summary, breed type, packaging format, muscle and muscle iron levels had a significant impact on colour stability of sheep meat in oxygen-available packaging systems.
•Sheep with higher proportion of Merino breed had lower colour stability.•Iron concentration was the most important covariate for colour stability.•High muscle iron concentration reduced retail shelf-life by ~2.3days in MAPO2 and by ~0.75days in over-wrap.•The effect of breed type was independent of packaging and iron concentration.
Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean ...change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing
and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.
Heteroatom doping into polyaromatic hydrocarbons (PAHs) is a powerful approach for modifying key physical properties, however, there are extremely few modular routes that enable facile formation of ...B-, B
- and B,N-(specifically not containing direct B-N bonds) doped PAHs despite the growing importance of these materials. Sequential, one pot borylative cyclisation/intramolecular electrophilic C-H borylation of naphthyl-alkynes provides a simple new route to access novel B-, B,N- and B
-doped (PAHs). The initial products, dihydronaphthalene/dihydroquinoline B-mesityl PAHs, were reacted with Ph
CBF
/pyridyl base to form the oxidised B-, and B,N-doped PAHs. However, for B-triisopropylphenyl (Trip) PAH congeners oxidation has to be performed prior to Trip installation due to preferential oxidation of an isopropylaryl moiety to the styrene. This alternative sequence enables access to Trip-B-PAHs and to structurally constrained B and B
-PAHs. Analysis of the solid state structures and optoelectronic properties of these PAHs confirm that frontier orbital energies, extended packing structures, Stokes shift and quantum yields all can be rationally modified using this methodology. The simplicity of this synthetic approach makes it a powerful tool for rapidly generating novel bench stable boron doped PAHs, which is important for facilitating further structure-property relationship studies and the wider utilisation of these materials in optoelectronic applications.
The rate at which dislocations nucleate from spherical voids subjected to shear loading is predicted from atomistic simulation. By employing the latest version of the finite temperature string ...method, a variational transition state theory approach can be utilized, enabling atomistic predictions at ordinary laboratory time scales, loads, and temperatures. The simulation results, in conjunction with a continuum model, show that the deformation and growth of voids in Al are not likely to occur via dislocation nucleation under typical loadings regardless of void size.
The insect juvenile hormone receptor is a basic helix-loop-helix (bHLH), Per-Arnt-Sim (PAS) domain protein, a novel type of hormone receptor. In higher flies like Drosophila, the ancestral receptor ...germ cell-expressed (gce) gene has duplicated to yield the paralog Methoprene-tolerant (Met). These paralogous receptors share redundant function during development but play unique roles in adults. Some aspects of JH function apparently require one receptor or the other. To provide a foundation for studying JH receptor function, we have recapitulated endogenous JH receptor expression with single cell resolution. Using Bacteria Artificial Chromosome (BAC) recombineering and a transgenic knock-in, we have generated a spatiotemporal expressional atlas of Met and gce throughout development. We demonstrate JH receptor expression in known JH target tissues, in which temporal expression corresponds with periods of hormone sensitivity. Larval expression largely supports the notion of functional redundancy. Furthermore, we provide the neuroanatomical distribution of JH receptors in both the larval and adult central nervous system, which will serve as a platform for future studies regarding JH action on insect behavior.
Predicting the rate at which dislocations overcome obstacles is key to understanding the microscopic features that govern the plastic flow of modern alloys. In this spirit, the current manuscript ...examines the rate at which an edge dislocation overcomes an obstacle in aluminum. Predictions were made using different popular variants of Harmonic Transition State Theory (HTST) and compared to those of direct Molecular Dynamics (MD) simulations. The HTST predictions were found to be grossly inaccurate due to the large entropy barrier associated with the dislocation–obstacle interaction. Considering the importance of finite temperature effects, the utility of the Finite Temperature String (FTS) method was then explored. While this approach was found capable of identifying a prominent reaction tube, it was not capable of computing the free energy profile along the tube. Lastly, the utility of the Transition Interface Sampling (TIS) approach was explored, which does not need a free energy profile and is known to be less reliant on the choice of reaction coordinate. The TIS approach was found capable of accurately predicting the rate, relative to direct MD simulations. This finding was utilized to examine the temperature and load dependence of the dislocation–obstacle interaction in a simple periodic cell configuration. An attractive rate prediction approach combining TST and simple continuum models is identified, and the strain rate sensitivity of individual dislocation obstacle interactions is predicted.
Data from samples of longissmus lumborum (LL) and semimembranosus (SM) muscles from 391 lamb carcasses, which had been packaged in overwrap (OW) or high oxygen modified atmosphere packaging (MAPO2) ...systems and then subjected to simulated retail display, were used to estimate genetic variation for colour stability traits of lamb meat as a step in identifying a trait for genetic evaluation. Traits included the ratio of the reflectance of light at wavelengths of 630 nm and 580 nm (oxy/met) measured at a single time point at the end of the display period (day 3 under OW; day 8 under MAPO2) and the predicted time for oxy/met to reach a benchmark value. Under OW and MAPO2, the measures of meat colour stability of the LL tended to be of moderate heritability (0.09–0.29), but for the SM were of low heritability (0–0.10). Improving retail colour stability of lamb loins through selection of genetically superior animals may be better based on measurement of oxy/met.
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