New incision rates along the Colorado River system based on cosmogenic burial dating of terraces: Implications for regional controls on Quaternary incision

New cosmogenic burial and published dates of Colorado and Green river terraces are used to infer variable incision rates along the rivers in the past 10 Ma. A knickpoint at Lees Ferry separates the lower and upper Colorado River basins. We obtained an isochron cosmogenic burial date of 1.5 ± 0.13 Ma on a 190-m-high strath terrace near Bullfrog Basin, Utah (upstream of Lees Ferry). This age yields an average incision rate of 126+12/-10m/Ma above the knickpoint and is three times older than a cosmogenic surface age on the same terrace, suggesting that surface dates inferred by exposure dating may be minimum ages. Incision rates below Lees Ferry are faster, ~170m/Ma-230m/Ma, suggesting upstream knickpoint migration over the past several million years. A terrace at Hite (above Lees Ferry) yields an isochron burial age of 0.29 ± 0.17 Ma, and a rate of ~300-900m/Ma, corroborating incision acceleration in Glen Canyon. Within the upper basin, isochron cosmogenic burial dates of 1.48 ± 0.12 Ma on a 60 m terrace near the Green River in Desolation Canyon, Utah, and 1.2 ± 0.3 Ma on a 120 m terrace upstream of Flaming Gorge, Wyoming, give incision rates of 41± 3m/Ma and 100+33/-20m/Ma, respectively. In contrast, incision rates along the upper Colorado River are 150m/Ma over 0.64 and 10 Ma time frames. Higher incision rates, gradient, and discharge along the upper Colorado River relative to the Green River are consistent with differential rock uplift of the Colorado Rockies relative to the Colorado Plateau

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Modern and ancient amalgamated sandy meander‐belt deposits: recognition and controls on development

Amalgamated sandy meander belts and their deposits are common in modern continental and marine‐connected basins yet comprise a minor constituent of the reported fluvial rock record. This suggests that either amalgamated meander‐belts are uncommon in the rock record or that the recognition criteria are lacking to identify sandy meandering river deposits. To address this apparent discrepancy, the authors document the range and occurrence of amalgamated sandy meander belts (ASMB) from modern basins and the stratigraphic record. ASMB are widely distributed throughout both present and rock record sedimentary basins occurring in foreland, extensional, cratonic, strike‐slip and passive margin basins. They occur in all climatic settings ranging from tundra to hot deserts. Three specific occurrences of ASMB are recognised in modern basins: in the proximal to medial parts of distributive fluvial systems (DFS), as laterally‐confined belts that mainly form axial fluvial systems; and as valley‐confined meander belts that may infill bedrock, alluvial or coastal plain valleys. From the limited amount of rock record examples of ASMB that are available, it is clear that they occur in similar settings to those observed in modern basins, the recognition of which provides a framework for the further prediction and identification of ASMB in the rock record. The lack of recognition of ASMB in the rock record is considered to be due to an absence of characteristics that allow clear distinction between sandy meandering and braided fluvial deposits. Characteristics considered common to both include: multi‐storey, laterally extensive (sheet‐like) amalgamated channel belts, dominance of downstream accreting bedforms, no fining upwards grain‐size profile and little or no fine‐grained sediment and/or soil preservation. In contrast, features considered characteristic of meandering rivers such as inclined heterolithic stratification, high palaeocurrent dispersion, single storey channels and fining upwards grain‐size profiles are absent. The authors suggest that no single criterion can be used to definitively identify sandy meander belt deposits in the rock record and that a combination of systematic variations in accretion direction, palaeocurrent dispersal patterns and recognition of storey scale accretion surfaces is necessary to identify clearly this fluvial style. The common occurrence and distribution of sandy meander belts in modern sedimentary basins together with their limited recognition in the rock record suggests that their true stratigraphic distribution has yet to be determined. This has important implications for palaeogeographic reconstructions, understanding the impact of plant colonisation on fluvial planform style and predicting sandstone body dimensions and internal heterogeneity distribution within hydrocarbon reservoirs and aquifers

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI): Study protocol for a multicentre, observational trial

Introduction More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. Methods and analysis EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. Ethics and dissemination EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369.