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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Braun, Judith, et al.
(författare)
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Full15N tracer accounting to revisit major assumptions of 15N isotope pool dilution approaches for gross nitrogen mineralization
- 2018
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717. ; 117, s. 16-26
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 The Authors The 15 N isotope pool dilution (IPD) technique is the only available method for measuring gross ammonium (NH 4 + ) production and consumption rates. Rapid consumption of the added 15 N-NH 4 + tracer is commonly observed, but the processes responsible for this consumption are not well understood. The primary objectives of this study were to determine the relative roles of biotic and abiotic processes in 15 N-NH 4 + consumption and to investigate the validity of one of the main assumptions of IPD experiments, i.e., that no reflux of the consumed 15 N tracer occurs during the course of the experiments. We added a 15 N-NH 4 + tracer to live and sterile (autoclaved) soil using mineral topsoil from a beech forest and a grassland in Austria that differed in NH 4 + concentrations and NH 4 + consumption kinetics. We quantified both biotic tracer consumption (i.e. changes in the concentrations and 15 N enrichments of NH 4 + , dissolved organic N (DON), NO 3 − and the microbial N pool) and abiotic tracer consumption (i.e., fixation by clay and/or humic substances). We achieved full recovery of the 15 N tracer in both soils over the course of the 48 h incubation. For the forest soil, we found no rapid consumption of the 15 N tracer, and the majority of tracer (78%) remained unconsumed at the end of the incubation period. In contrast, the grassland soil showed rapid 15 N-NH 4 + consumption immediately after tracer addition, which was largely due to both abiotic fixation (24%) and biotic processes, largely uptake by soil microbes (10%) and nitrification (13%). We found no evidence for reflux of 15 N-NH 4 + over the 48 h incubation period in either soil. Our study therefore shows that 15 N tracer reflux during IPD experiments is negligible for incubation times of up to 48 h, even when rapid NH 4 + consumption occurs. Such experiments are thus robust to the assumption that immobilized labeled N is not re–mobilized during the experimental period and does not impact calculations of gross N mineralization.
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| 3. |
- Abbasi, Rasha, et al.
(författare)
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IceCube search for neutrinos from GRB 221009A
- 2023
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Ingår i: Proceedings of 38th International Cosmic Ray Conference (ICRC 2023). - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- GRB 221009A is the brightest Gamma Ray Burst (GRB) ever observed. The observed extremelyhigh flux of high and very-high-energy photons provide a unique opportunity to probe the predictedneutrino counterpart to the electromagnetic emission. We have used a variety of methods to searchfor neutrinos in coincidence with the GRB over several time windows during the precursor, promptand afterglow phases of the GRB. MeV scale neutrinos are studied using photo-multiplier ratescalers which are normally used to search for galactic core-collapse supernovae neutrinos. GeVneutrinos are searched starting with DeepCore triggers. These events don’t have directionallocalization, but instead can indicate an excess in the rate of events. 10 GeV - 1 TeV and >TeVneutrinos are searched using traditional neutrino point source methods which take into accountthe direction and time of events with DeepCore and the entire IceCube detector respectively. The>TeV results include both a fast-response analysis conducted by IceCube in real-time with timewindows of T0 − 1 to T0 + 2 hours and T0 ± 1 day around the time of GRB 221009A, as well asan offline analysis with 3 new time windows up to a time window of T0 − 1 to T0 + 14 days, thelongest time period we consider. The combination of observations by IceCube covers 9 ordersof magnitude in neutrino energy, from MeV to PeV, placing upper limits across the range forpredicted neutrino emission.
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| 4. |
- Albert, Christian, et al.
(författare)
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Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy : A Systematic Review and Meta-analysis
- 2020
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Ingår i: American Journal of Kidney Diseases. - : Elsevier BV. - 0272-6386 .- 1523-6838. ; 76:6, s. 826-
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Forskningsöversikt (refereegranskat)abstract
- Rationale & Objective: The usefulness of measures of neutrophil gelatinase-associated lipocalin (NGAL) in urine or plasma obtained on clinical laboratory platforms for predicting acute kidney injury (AKI) and AKI requiring dialysis (AKI-D) has not been fully evaluated. We sought to quantitatively summarize published data to evaluate the value of urinary and plasma NGAL for kidney risk prediction.Study Design: Literature-based meta-analysis and individual-study-data meta-analysis of diagnostic studies following PRISMA-IPD guidelines.Setting & Study Populations: Studies of adults investigating AKI, severe AKI, and AKI-D in the setting of cardiac surgery, intensive care, or emergency department care using either urinary or plasma NGAL measured on clinical laboratory platforms.Selection Criteria for Studies: PubMed, Web of Science, Cochrane Library, Scopus, and congress abstracts ever published through February 2020 reporting diagnostic test studies of NGAL measured on clinical laboratory platforms to predict AKI.Data Extraction: Individual-study-data meta analysis was accomplished by giving authors data specifications tailored to their studies and requesting standardized patient-level data analysis.Analytical Approach: Individual-study-data meta analysis used a bivariate time-to-event model for interval-censored data from which discriminative ability (AUC) was characterized. NGAL cutoff concentrations at 95% sensitivity, 95% specificity, and optimal sensitivity and specificity were also estimated. Models incorporated as confounders the clinical setting and use versus nonuse of urine output as a criterion for AKI. A literature-based meta-analysis was also performed for all published studies including those for which the authors were unable to provide individual-study data analyses.Results: We included 52 observational studies involving 13,040 patients. We analyzed 30 data sets for the individual-study-data meta-analysis. For AKI, severe AKI, and AKI-D, numbers of events were 837, 304, and 103 for analyses of urinary NGAL, respectively; these values were 705, 271, and 178 for analyses of plasma NGAL. Discriminative performance was similar in both meta-analyses. Individual-study-data meta-analysis AUCs for urinary NGAL were 0.75 (95% CI, 0.73-0.76) and 0.80 (95% CI, 0.79-0.81) for severe AKI and AKI-D, respectively; for plasma NGAL, the corresponding AUCs were 0.80 (95% CI, 0.790.81) and 0.86 (95% CI, 0.84-0.8 6). Cutoff concentrations at 95% specificity for urinary NGAL were >580 ng/mL with 27% sensitivity for severe AKI and >589 ng/mL with 24% sensitivity for AKI-D. Corresponding cutoffs for plasma NGAL were >364 ng/mL with 44% sensitivity and >546 ng/mL with 26% sensitivity, respectively.Limitations: Practice variability in initiation of dialysis. Imperfect harmonization of data across studies. Conclusions: Urinary and plasma NGAL concentrations may identify patients at high risk for AKI in clinical research and practice. The cutoff concentrations reported in this study require prospective evaluation.
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| 5. |
- Collentine, Dennis, et al.
(författare)
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Consequences of future nutrient load scenarios on multiple benefits of agricultural production
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Nutrient load rates to the Baltic Sea need to be reduced. Agricultural land is regarded as the most significant contributor to the loads, and measures to reduce losses of nitrogen (N) and phosphorus (P) loads have been proposed, both for the near and far future. Agricultural production was to a large extent considered in these scenarios, whereas effects on other ecosystem services were not evaluated. The question to be answered by this report is whether the measures adopted to reduce N and P losses improve or impair multiple benefits of agriculture. The question is answered for a specific catchment (Svärtaån) located in Sweden, but the method is thoroughly described to provide a potential method to also evaluate other catchments. This work was performed as a part of the Baltic Compass project (2013). The answer to the main question of whether the measures adopted to reduce N and P losses from agricultural fields improved or impaired multiple benefits of agriculture, seems to be that they improved. Most of the BAP measures had a positive influence on most of the MB-categories, the clearest exception being liming in tile drains which only improved the cost effectiveness. Except for water protection, the biosecurity MB-category was positively influenced by the most measures (6 out of 9) and with soil quality the next highest (5 out of 9). It is less clear how the absolute values evaluated for the MB index, can be compared among MB-categories. Among the BAP-measures, structural liming was the most positive measure (summing up the indices of all MB-categories), followed by buffer-zones and spring cultivation the next, although the cost effectiveness of these latter measures was evaluated to decrease. In the “unavoidable” future (Future scenarios) GHG emissions strongly increased. The only measure that mitigated that effect was reduced N fertilisation, providing more arguments for applying reduced fertilisation than only to reduce leaching.
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| 7. |
- Massart, Annick, et al.
(författare)
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The DESCARTES-Nantes survey of kidney transplant recipients displaying clinical operational tolerance identifies 35 new tolerant patients and 34 almost tolerant patients
- 2016
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 31:6, s. 1002-1013
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Tidskriftsartikel (refereegranskat)abstract
- Background. Kidney recipients maintaining a prolonged allograft survival in the absence of immunosuppressive drugs and without evidence of rejection are supposed to be exceptional. The ERA-EDTA-DESCARTES working group together with Nantes University launched a European-wide survey to identify new patients, describe them and estimate their frequency for the first time. Methods. Seventeen coordinators distributed a questionnaire in 256 transplant centres and 28 countries in order to report as many 'operationally tolerant' patients (TOL; defined as having a serum creatinine <1.7 mg/dL and proteinuria <1 g/day or g/g creatinine despite at least 1 year without any immunosuppressive drug) and 'almost tolerant' patients (minimally immunosuppressed patients (MIS) receiving low-dose steroids) as possible. We reported their number and the total number of kidney transplants performed at each centre to calculate their frequency. Results. One hundred and forty-seven questionnaires were returned and we identified 66 TOL (61 with complete data) and 34 MIS patients. Of the 61 TOL patients, 26 were previously described by the Nantes group and 35 new patients are presented here. Most of them were noncompliant patients. At data collection, 31/35 patients were alive and 22/31 still operationally tolerant. For the remaining 9/31, 2 were restarted on immunosuppressive drugs and 7 had rising creatinine of whom 3 resumed dialysis. Considering all patients, 10-year death-censored graft survival post-immunosuppression weaning reached 85% in TOL patients and 100% in MIS patients. With 218 913 kidney recipients surveyed, cumulative incidences of operational tolerance and almost tolerance were estimated at 3 and 1.5 per 10 000 kidney recipients, respectively. Conclusions. In kidney transplantation, operational tolerance and almost tolerance are infrequent findings associated with excellent long-term death-censored graft survival.
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