Distinct Contributions of Eroding and Depositional Profiles to Land-Atmosphere CO2 Exchange in Two Contrasting Forests

This work is licensed under a Creative Commons Attribution 4.0 International License.Lateral movements of soil organic C (SOC) influence Earth's C budgets by transporting organic C across landscapes and by modifying soil-profile fluxes of CO2. We extended a previously presented model (Soil Organic C Erosion Replacement and Oxidation, SOrCERO) and present SOrCERODe, a model with which we can project how erosion and subsequent deposition of eroded material can modify biosphere-atmosphere CO2 fluxes in watersheds. The model permits the user to quantify the degree to which eroding and depositional profiles experience a change in SOC oxidation and production as formerly deep horizons become increasingly shallow, and as depositional profiles are buried. To investigate the relative importance of erosion rate, evolving SOC depth distributions, and mineralization reactivity on modeled soil C fluxes, we examine two forests exhibiting distinct depth distributions of SOC content and reactivity, hydrologic regimes and land use. Model projections suggest that, at decadal to centennial timescales: (1) the quantity of SOC moving across a landscape depends on erosion rate and the degree to which SOC production and oxidation at the eroding profile are modified as deeper horizons become shallower, and determines the degree to which depositional profile SOC fluxes are modified; (2) erosional setting C sink strength increases with erosion rate, with some sink effects reaching more than 40% of original profile SOC content after 100 y of a relatively high erosion rate (i.e., 1 mm y−1); (3) even large amounts of deposited SOC may not promote a large depositional profile C sink even with large gains in autochthonous SOC post-deposition if oxidation of buried SOC is not limited; and (4) when modeled depositional settings receive a disproportionately large amount of SOC, simulations of strong C sink scenarios mimic observations of modest preservation of buried SOC and large SOC gains in surficial horizons, suggesting that C sink scenarios have merit in these forests. Our analyses illuminate the importance of cross-landscape linkages between upland and depositional environments for watershed-scale biosphere-atmosphere C fluxes, and emphasize the need for accurate representations and observations of time-varying depth distributions of SOC reactivity across evolving watersheds if we seek accurate projections of ecosystem C balances

Distinct Contributions of Eroding and Depositional Profiles to Land-Atmosphere CO2 Exchange in Two Contrasting Forests

Lateral movements of soil organic C (SOC) influence Earth's C budgets by transporting organic C across landscapes and by modifying soil-profile fluxes of CO2. We extended a previously presented model (Soil Organic C Erosion Replacement and Oxidation, SOrCERO) and present SOrCERODe, a model with which we can project how erosion and subsequent deposition of eroded material can modify biosphere-atmosphere CO2 fluxes in watersheds. The model permits the user to quantify the degree to which eroding and depositional profiles experience a change in SOC oxidation and production as formerly deep horizons become increasingly shallow, and as depositional profiles are buried. To investigate the relative importance of erosion rate, evolving SOC depth distributions, and mineralization reactivity on modeled soil C fluxes, we examine two forests exhibiting distinct depth distributions of SOC content and reactivity, hydrologic regimes and land use. Model projections suggest that, at decadal to centennial timescales: (1) the quantity of SOC moving across a landscape depends on erosion rate and the degree to which SOC production and oxidation at the eroding profile are modified as deeper horizons become shallower, and determines the degree to which depositional profile SOC fluxes are modified; (2) erosional setting C sink strength increases with erosion rate, with some sink effects reaching more than 40% of original profile SOC content after 100 y of a relatively high erosion rate (i.e., 1 mm y−1); (3) even large amounts of deposited SOC may not promote a large depositional profile C sink even with large gains in autochthonous SOC post-deposition if oxidation of buried SOC is not limited; and (4) when modeled depositional settings receive a disproportionately large amount of SOC, simulations of strong C sink scenarios mimic observations of modest preservation of buried SOC and large SOC gains in surficial horizons, suggesting that C sink scenarios have merit in these forests. Our analyses illuminate the importance of cross-landscape linkages between upland and depositional environments for watershed-scale biosphere-atmosphere C fluxes, and emphasize the need for accurate representations and observations of time-varying depth distributions of SOC reactivity across evolving watersheds if we seek accurate projections of ecosystem C balances

Global nitrogen budgets in cereals: A 50-year assessment for maize, rice, and wheat production systems

Industrially produced N-fertilizer is essential to the production of cereals that supports current and projected human populations. We constructed a top-down global N budget for maize, rice, and wheat for a 50-year period (1961 to 2010). Cereals harvested a total of 1551 Tg of N, of which 48% was supplied through fertilizer-N and 4% came from net soil depletion. An estimated 48% (737 Tg) of crop N, equal to 29, 38, and 25 kg ha−1 yr−1 for maize, rice, and wheat, respectively, is contributed by sources other than fertilizer- or soil-N. Non-symbiotic N2 fixation appears to be the major source of this N, which is 370 Tg or 24% of total N in the crop, corresponding to 13, 22, and 13 kg ha−1 yr−1 for maize, rice, and wheat, respectively. Manure (217 Tg or 14%) and atmospheric deposition (96 Tg or 6%) are the other sources of N. Crop residues and seed contribute marginally. Our scaling-down approach to estimate the contribution of non-symbiotic N2 fixation is robust because it focuses on global quantities of N in sources and sinks that are easier to estimate, in contrast to estimating N losses per se, because losses are highly soil-, climate-, and crop-specific

Budd-Chiari Syndrome: Long term success via hepatic decompression using transjugular intrahepatic porto-systemic shunt

<p>Abstract</p> <p>Background</p> <p>Budd-Chiari syndrome (BCS) generally implies thrombosis of the hepatic veins and/or the intrahepatic or suprahepatic inferior vena cava. Treatment depends on the underlying cause, the anatomic location, the extent of the thrombotic process and the functional capacity of the liver. It can be divided into medical treatment including anticoagulation and thrombolysis, radiological procedures such as angioplasty and transjugular intrahepatic porto-systemic shunt (TIPS) and surgical interventions including orthotopic liver transplantation (OLT). Controlled trials or reports on larger cohorts are limited due to rare disease frequency. The aim of this study was to report our single centre long term results of patients with BCS receiving one of three treatment options i.e. medication only, TIPS or OLT on an individually based decision of our local expert group.</p> <p>Methods</p> <p>20 patients with acute, subacute or chronic BCS were treated between 1988 and 2008. Clinical records were analysed with respect to underlying disease, therapeutic interventions, complications and overall outcome.</p> <p>Results</p> <p>16 women and 4 men with a mean age of 34 ± 12 years (range: 14-60 years) at time of diagnosis were included. Myeloproliferative disorders or a plasmatic coagulopathy were identified as underlying disease in 13 patients, in the other patients the cause of BCS remained unclear. 12 patients presented with an acute BCS, 8 with a subacute or chronic disease. 13 patients underwent TIPS, 4 patients OLT as initial therapy, 2 patients required only symptomatic therapy, and one patient died from liver failure before any specific treatment could be initiated. Eleven of 13 TIPS patients required 2.5 ± 2.4 revisions (range: 0-8). One patient died from his underlying hematologic disease. The residual 12 patients still have stable liver function not requiring OLT. All 4 patients who underwent OLT as initial treatment, required re-OLT due to thrombembolic complications of the graft. Survival in the TIPS group was 92.3% and in the OLT group 75% during a median follow-up of 4 and 11.5 years, respectively.</p> <p>Conclusion</p> <p>Our results confirm the role of TIPS in the management of patients with acute, subacute and chronic BCS. The limited number of patients with OLT does not allow to draw a meaningful conclusion. However, the underlying disease may generate major complications, a reason why OLT should be limited to patients who cannot be managed by TIPS.</p

International Pediatric ORL Group (IPOG) laryngomalacia consensus recommendations

Objective To provide recommendations for the comprehensive management of young infants who present with signs or symptoms concerning for laryngomalacia. Methods Expert opinion by the members of the International Pediatric Otolaryngology Group (IPOG). Results Consensus recommendations include initial care and triage recommendations for health care providers who commonly evaluate young infants with noisy breathing. The consensus statement also provides comprehensive care recommendations for otolaryngologists who manage young infants with laryngomalacia including: evaluation and treatment considerations for commonly debated issues in laryngomalacia, initial work-up of infants presenting with inspiratory stridor, treatment recommendations based on disease severity, management of the infant with feeding difficulties, post-surgical treatment management recommendations, and suggestions for acid suppression therapy. Conclusion Laryngomalacia care consensus recommendations are aimed at improving patient-centered care in infants with laryngomalacia

Outcome of COVID-19 in hospitalised immunocompromised patients:An analysis of the WHO ISARIC CCP-UK prospective cohort study

Background: Immunocompromised patients may be at higher risk of mortality if hospitalised with Coronavirus Disease 2019 (COVID-19) compared with immunocompetent patients. However, previous studies have been contradictory. We aimed to determine whether immunocompromised patients were at greater risk of in-hospital death and how this risk changed over the pandemic. Methods and findings: We included patients &gt; = 19 years with symptomatic community-acquired COVID-19 recruited to the ISARIC WHO Clinical Characterisation Protocol UK prospective cohort study. We defined immunocompromise as immunosuppressant medication preadmission, cancer treatment, organ transplant, HIV, or congenital immunodeficiency. We used logistic regression to compare the risk of death in both groups, adjusting for age, sex, deprivation, ethnicity, vaccination, and comorbidities. We used Bayesian logistic regression to explore mortality over time. Between 17 January 2020 and 28 February 2022, we recruited 156,552 eligible patients, of whom 21,954 (14%) were immunocompromised. Approximately 29% (n = 6,499) of immunocompromised and 21% (n = 28,608) of immunocompetent patients died in hospital. The odds of in-hospital mortality were elevated for immunocompromised patients (adjusted OR 1.44, 95% CI [1.39, 1.50], p &lt; 0.001). Not all immunocompromising conditions had the same risk, for example, patients on active cancer treatment were less likely to have their care escalated to intensive care (adjusted OR 0.77, 95% CI [0.7, 0.85], p &lt; 0.001) or ventilation (adjusted OR 0.65, 95% CI [0.56, 0.76], p &lt; 0.001). However, cancer patients were more likely to die (adjusted OR 2.0, 95% CI [1.87, 2.15], p &lt; 0.001). Analyses were adjusted for age, sex, socioeconomic deprivation, comorbidities, and vaccination status. As the pandemic progressed, in-hospital mortality reduced more slowly for immunocompromised patients than for immunocompetent patients. This was particularly evident with increasing age: the probability of the reduction in hospital mortality being less for immunocompromised patients aged 50 to 69 years was 88% for men and 83% for women, and for those &gt;80 years was 99% for men and 98% for women. The study is limited by a lack of detailed drug data prior to admission, including steroid doses, meaning that we may have incorrectly categorised some immunocompromised patients as immunocompetent. Conclusions: Immunocompromised patients remain at elevated risk of death from COVID-19. Targeted measures such as additional vaccine doses, monoclonal antibodies, and nonpharmaceutical preventive interventions should be continually encouraged for this patient group. Trial registration: ISRCTN 66726260

Towards Electrosynthesis in Shewanella: Energetics of Reversing the Mtr Pathway for Reductive Metabolism

Bioelectrochemical systems rely on microorganisms to link complex oxidation/reduction reactions to electrodes. For example, in Shewanella oneidensis strain MR-1, an electron transfer conduit consisting of cytochromes and structural proteins, known as the Mtr respiratory pathway, catalyzes electron flow from cytoplasmic oxidative reactions to electrodes. Reversing this electron flow to drive microbial reductive metabolism offers a possible route for electrosynthesis of high value fuels and chemicals. We examined electron flow from electrodes into Shewanella to determine the feasibility of this process, the molecular components of reductive electron flow, and what driving forces were required. Addition of fumarate to a film of S. oneidensis adhering to a graphite electrode poised at −0.36 V versus standard hydrogen electrode (SHE) immediately led to electron uptake, while a mutant lacking the periplasmic fumarate reductase FccA was unable to utilize electrodes for fumarate reduction. Deletion of the gene encoding the outer membrane cytochrome-anchoring protein MtrB eliminated 88% of fumarate reduction. A mutant lacking the periplasmic cytochrome MtrA demonstrated more severe defects. Surprisingly, disruption of menC, which prevents menaquinone biosynthesis, eliminated 85% of electron flux. Deletion of the gene encoding the quinone-linked cytochrome CymA had a similar negative effect, which showed that electrons primarily flowed from outer membrane cytochromes into the quinone pool, and back to periplasmic FccA. Soluble redox mediators only partially restored electron transfer in mutants, suggesting that soluble shuttles could not replace periplasmic protein-protein interactions. This work demonstrates that the Mtr pathway can power reductive reactions, shows this conduit is functionally reversible, and provides new evidence for distinct CymA:MtrA and CymA:FccA respiratory units

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Testing Biochemistry Revisited: How In Vivo Metabolism Can Be Understood from In Vitro Enzyme Kinetics

A decade ago, a team of biochemists including two of us, modeled yeast glycolysis and showed that one of the most studied biochemical pathways could not be quite understood in terms of the kinetic properties of the constituent enzymes as measured in cell extract. Moreover, when the same model was later applied to different experimental steady-state conditions, it often exhibited unrestrained metabolite accumulation