Soil thickness is a fundamental variable in many earth science disciplines due to its critical role in many hydrological and ecological processes, but it is difficult to predict. Here we show a ...strong linear relationship (r
= 0.87, RMSE = 0.19 m) between soil thickness and hillslope curvature across both convergent and divergent parts of the landscape at a field site in Idaho. We find similar linear relationships across diverse landscapes (n = 6) with the slopes of these relationships varying as a function of the standard deviation in catchment curvatures. This soil thickness-curvature approach is significantly more efficient and just as accurate as kriging-based methods, but requires only high-resolution elevation data and as few as one soil profile. Efficiently attained, spatially continuous soil thickness datasets enable improved models for soil carbon, hydrology, weathering, and landscape evolution.
The critical zone has been the subject of much discussion and debate as a term in the ecosystem, soil and earth system science communities, and there is a need to reconcile how this term is used ...within these disciplines. I suggest that much like watershed and soil ecosystems, the critical zone is an ecosystem and is defined by deeper spatial and temporal boundaries to study its structure and function. Critical zone science, however, expands the scope of ecosystem and soil science and more fully embraces the integration of earth sciences, ecology, and hydrology to understand key mechanisms driving critical zone functions in a place-based setting. This integration of multiple perspectives and expertise is imperative to make new discoveries at the interface of these disciplines. I offer solid examples highlighting how critical zone science as an integrative science contributes to ecosystem and soil sciences and exemplify this emerging field.
BACKGROUND AND PURPOSEThe Woven EndoBridge (WEB) device is an established technique for the treatment of intracranial aneurysms. Occasionally, persistent opacification inside the WEB lumen can be ...observed at follow-up (previously described as Bicêtre Occlusion Scale Score 1). We evaluated potential risk factors of this phenomenon, hypothesizing that initial deviation of the WEB device from the aneurysm axis, size of the aneurysmal neck surface, or inappropriate WEB sizing correlates with Bicêtre Occlusion Scale Score 1 findings. MATERIALS AND METHODSWe systematically reviewed all patients treated with the WEB device between February 2014 and December 2018 in our neurointerventional center. Patients with midterm follow-up DSA available were considered for aneurysm evaluation applying the Bicêtre Occlusion Scale Score. WEB angle deviation from the aneurysm axis, neck widths, and WEB sizes were collected. RESULTSWe included 65 patients with 67 intracranial aneurysms. Eleven of 67 (16.4%) intracranial aneurysms showed the Bicêtre Occlusion Scale Score 1 phenomenon at follow-up. Anterior-posterior projections of WEB axis deviation (angles measured in degrees) were significantly different between the Bicêtre Occlusion Scale Score 1 cohort (median ± interquartile range, 17 ± 17) and all other Bicêtre Occlusion Scale Scores (median ± interquartile range, 7 ± 11; P = .023), whereas in lateral projections, no significant difference was observed (median ± interquartile range, 10 ± 10 versus 8 ± 9; P = .169). Neck or aneurysm recurrence, but not the Bicêtre Occlusion Scale Score 1 phenomenon, occurred significantly more often in patients with inappropriate WEB sizing compared with appropriate WEB sizing (median ± interquartile range, 1 ± 1.3 versus 0 ± 0; P < .001/P = .664). CONCLUSIONSThe Bicêtre Occlusion Scale Score 1 phenomenon is associated with an initial deviation of the WEB device from the aneurysm axis but does not correlate with aneurysmal neck surface measurements or WEB sizing.
Urban watersheds are often sources of nitrogen (N) to downstream systems, contributing to poor water quality. However, it is unknown which components (e.g., land cover and stormwater infrastructure ...type) of urban watersheds contribute to N export and which may be sites of retention. In this study we investigated which watershed characteristics control N sourcing, biogeochemical processing of nitrate (NO3 –) during storms, and the amount of rainfall N that is retained within urban watersheds. We used triple isotopes of NO3 – (δ15N, δ18O, and Δ17O) to identify sources and transformations of NO3 – during storms from 10 nested arid urban watersheds that varied in stormwater infrastructure type and drainage area. Stormwater infrastructure and land coverretention basins, pipes, and grass coverdictated the sourcing of NO3 – in runoff. Urban watersheds were strong sinks or sources of N to stormwater depending on runoff, which in turn was inversely related to retention basin density and positively related to imperviousness and precipitation. Our results suggest that watershed characteristics control the sources and transport of inorganic N in urban stormwater but that retention of inorganic N at the time scale of individual runoff events is controlled by hydrologic, rather than biogeochemical, mechanisms.
Summary
Background
Acute‐on‐chronic liver failure (ACLF) is a severe complication of liver cirrhosis associated with excess short‐term mortality rates. Orthotopic liver transplantation (OLT) is a ...potentially life‐saving therapeutic modality for acute‐on‐chronic liver failure patients, but selection of transplant candidates with an acceptable post‐transplant outcome is difficult.
Aim
To assess the risk of liver transplantation in patients with ACLF, and to determine parameters that predict post‐transplant survival in this patient cohort.
Methods
We retrospectively analysed all 250 patients with cirrhosis who underwent their first liver transplantation between 2009 and 2014 at our institution, and assessed post‐transplant outcomes.
Results
Of 250 cirrhotic liver transplant recipients, 98 patients fulfilled the diagnostic criteria for acute‐on‐chronic liver failure in the 3‐month pre‐transplant period. Compared to non‐ACLF patients, ACLF was associated with significantly higher short‐term morbidity and mortality after liver transplantation (90‐day patient survival 96.1% non‐ACLF vs 72.4% ACLF patients, P < 0.0001). Clinical improvement in the pre‐transplant period, as defined by recovery of at least one previously failed organ system, was observed in 37 of 98 acute‐on‐chronic liver failure patients, mostly within several days after diagnosis. Most notably, clinical improvement prior to liver transplantation was associated with excellent post‐transplant survival rates that approximated non‐ACLF transplant recipients. Following the 90‐day post‐transplant period, patient survival and long‐term graft functions were comparable between ACLF and non‐ACLF liver transplant recipients for up to 5 years.
Conclusions
Acute‐on‐chronic liver failure predicts adverse outcome after orthotopic liver transplantation. Given the dismal prognosis without transplantation, however, our results indicate that ACLF patients can be transplanted with comparably good outcomes, in particular patients who improve under conservative therapeutic measures.
Linked ContentThis article is linked to Izzy and Watt, and Huebener et al papers. To view these articles visit https://doi.org/10.1111/apt.14679 and https://doi.org/10.1111/apt.14804.
Topography plays a critical role in controlling rates of nitrogen (N) transformation and loss to streams through its effects on reaction and transport, yet few studies have coupled measurements of ...soil N cycling within a catchment to hydrologic N losses and sources of those losses. We examined the processes controlling temporal patterns of stream N export using hydrometric methods and dual isotopes of nitrate (NO3−) in a small headwater catchment on the coast of Northern California. Soil nitrate pools accumulated in the hollow during the dry summer due to sustained rates of net nitrification and elevated soil moisture, and then contributed to the first flush of NO3− in macropore soil‐water and stream water in the winter. Macropore soil‐waters had higher concentrations of all forms of N than matrix soil‐waters, especially in the hollow. A plot of stream water δ15N versus δ18O values in NO3− indicated that NO3− was primarily derived from nitrification or microbial NO3−. Further analysis revealed a mixing of two microbial NO3− sources combined with seasonal progressive denitrification. Mass balance estimates suggested microbial NO3− was consumed by denitrification when conditions of high NO3−, dissolved organic matter, and soil‐water contents converged. Our study is the first to show a mixing of two sources of microbial NO3− and seasonal progressive denitrification using dual isotopes. Our observations suggest that the physical conditions in the convergent hollow are important constraints on stream N chemistry, and that shifts in runoff mechanisms and flow paths control the source and mixing of NO3− from various watershed sources.
Key Points
Our study shows mixing of two sources of nitrate and progressive denitrification
The physical conditions of the hollow constrain final stream N chemistry
Shifts in flow paths control sources and mixing of nitrate
To understand the hydrologic and biogeochemical controls on the age and recalcitrance of dissolved organic matter (DOM) found in stream waters, we combined hydrometric monitoring along a topographic ...gradient from ridge to channel with isotopic (13C and 14C) and spectroscopic (UV and 13C nuclear magnetic resonance) analyses of soil and stream water samples in a small coastal watershed in California. With increasing discharge, dissolved organic carbon concentrations increased from 2.2 to 10.9 mg C L-1, delta 14C values increased from -125 to +120 per thousand, delta 13C values decreased from -24 to -29 per thousand, C:N ratios increased from 6.5 to 15.4, and specific UV adsorption increased from 1.4 to 3.8 L mg C-1 m-1. These changes in DOM composition are consistent with a shift in source from old and recalcitrant soil organic matter (OM) sources found in deep soil horizons to young and relatively fresh OM sources found in the surface horizons. Results from this study suggest upland soils of the watershed become DOM production limited as indicated by a seasonal depletion and chemical shift in soil DOM, whereas highly productive soils in the hollow act as a near-infinite DOM source. Hydrologic connectivity of this DOM-rich riparian source region to the stream ultimately constrains DOM export, and the stream DOM composition reflects the combined influence of soil biogeochemical cycling of OM and hydrologic routing of water through the landscape.
Background Despite hospital staffs high vaccination priority due to recurrent patient contacts, COV1D-19 vaccination hesitancy in this group is alarming. In the general population, the previous ...uptake of influenza vaccination increases the likelihood of COVID-19 vaccination. The aim of the present study was, therefore, to investigate attitudes towards COVID-19 compared to influenza vaccination among hospital staff. Method Three samples were recruited from employees of the University Medical Center Hamburg-Eppendorf: an Influenza vaccination group (n = 167), a COVID-19 vaccination (n-671), and a COVID-19 refuser group (n = 54). All three samples answered numerical rating scales on the subjective risk of the respective infection to themselves and in general, the risk of vaccination and its perceived efficacy. COVID-19 vaccination refusers could also select the three most important reasons for refusal from a list and provide additional reasons via an open-ended item. Results COVID-19 vaccination refusers rated the risk of infection for themselves and in general as well as the efficacy of the vaccine lowest and the risk of the vaccine highest. Their most frequently provided reasons for refusal were possible side effects (67%), pregnancy (52%), and perceived pressure to vaccinate (46%). Conclusion Hospital staff who had been vaccinated against influenza or COVID-19 reported comparable risk-benefit assessments* although the latter is a comparatively new vaccine. Our results show a relatively high propensity to vaccinate against COVID-19 among hospital staff, with a simultaneous need to balance vaccine information, the need for vaccination, and voluntary uptake in future vaccination campaigns.
Abstract
From hillslope to small catchment scales (< 50 km
2
), soil carbon management and mitigation policies rely on estimates and projections of soil organic carbon (SOC) stocks. Here we apply a ...process-based modeling approach that parameterizes the MIcrobial-MIneral Carbon Stabilization (MIMICS) model with SOC measurements and remotely sensed environmental data from the Reynolds Creek Experimental Watershed in SW Idaho, USA. Calibrating model parameters reduced error between simulated and observed SOC stocks by 25%, relative to the initial parameter estimates and better captured local gradients in climate and productivity. The calibrated parameter ensemble was used to produce spatially continuous, high-resolution (10 m
2
) estimates of stocks and associated uncertainties of litter, microbial biomass, particulate, and protected SOC pools across the complex landscape. Subsequent projections of SOC response to idealized environmental disturbances illustrate the spatial complexity of potential SOC vulnerabilities across the watershed. Parametric uncertainty generated physicochemically protected soil C stocks that varied by a mean factor of 4.4 × across individual locations in the watershed and a − 14.9 to + 20.4% range in potential SOC stock response to idealized disturbances, illustrating the need for additional measurements of soil carbon fractions and their turnover time to improve confidence in the MIMICS simulations of SOC dynamics.
Numerous studies have examined bacterial communities in biological soil crusts (BSCs) associated with warm arid to semiarid ecosystems. Few, however, have examined bacterial communities in BSCs ...associated with cold steppe ecosystems, which often span a wide range of climate conditions and are sensitive to trends predicted by relevant climate models. Here, we utilized Illumina sequencing to examine BSC bacterial communities with respect to climatic gradients (elevation), land management practices (grazing vs. non-grazing), and shrub/intershrub patches in a cold sagebrush steppe ecosystem in southwestern Idaho, United States. Particular attention was paid to shifts in bacterial community structure and composition. BSC bacterial communities, including keystone N-fixing taxa, shifted dramatically with both elevation and shrub-canopy microclimates within elevational zones. BSC cover and BSC cyanobacteria abundance were much higher at lower elevation (warmer and drier) sites and in intershrub areas. Shrub-understory BSCs were significantly associated with several non-cyanobacteria diazotrophic genera, including
and
-
-
-
. High elevation (wetter and colder) sites had distinct, highly diverse, but low-cover BSC communities that were significantly indicated by non-cyanobacterial diazotrophic taxa including families in the order Rhizobiales and the family Frankiaceae. Abiotic soil characteristics, especially pH and ammonium, varied with both elevation and shrub/intershrub level, and were strongly associated with BSC community composition. Functional inference using the PICRUSt pipeline identified shifts in putative N-fixing taxa with respect to both the elevational gradient and the presence/absence of shrub canopy cover. These results add to current understanding of biocrust microbial ecology in cold steppe, serving as a baseline for future mechanistic research.
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