Still Arctic? — The changing Barents Sea

The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and autumn. Observations over recent decades show that surface air and ocean temperatures have increased, sea-ice extent has decreased, ocean stratification has weakened, and water chemistry and ecosystem components have changed, the latter in a direction often described as “Atlantification” or “borealisation,” with a less “Arctic” appearance. Temporal and spatial changes in the Barents Sea have a wider relevance, both in the context of large-scale climatic (air, water mass and sea-ice) transport processes and in comparison to other Arctic regions. These observed changes also have socioeconomic consequences, including for fisheries and other human activities. While several of the ongoing changes are monitored and quantified, observation and knowledge gaps remain, especially for winter months when field observations and sample collections are still sparse. Knowledge of the interplay of physical and biogeochemical drivers and ecosystem responses, including complex feedback processes, needs further development.Still Arctic? — The changing Barents SeapublishedVersio

Performance of creatinine-based equations to estimate glomerular filtration rate in White and Black populations in Europe, Brazil and Africa.

peer reviewed("[en] BACKGROUND: A new Chronic Kidney Disease Epidemiology Collaboration equation without the race variable has been recently proposed (CKD-EPIAS). This equation has neither been validated outside USA nor compared with the new European Kidney Function Consortium (EKFC) and Lund-Malmö Revised (LMREV) equations, developed in European cohorts. METHODS: Standardized creatinine and measured glomerular filtration rate (GFR) from the European EKFC cohorts (n = 13 856 including 6031 individuals in the external validation cohort), from France (n = 4429, including 964 Black Europeans), from Brazil (n = 100) and from Africa (n = 508) were used to test the performances of the equations. A matched analysis between White Europeans and Black Africans or Black Europeans was performed. RESULTS: In White Europeans (n = 9496), both the EKFC and LMREV equations outperformed CKD-EPIAS (bias of -0.6 and -3.2, respectively versus 5.0 mL/min/1.73 m², and accuracy within 30% of 86.9 and 87.4, respectively, versus 80.9%). In Black Europeans and Black Africans, the best performance was observed with the EKFC equation using a specific Q-value (= concentration of serum creatinine in healthy males and females). These results were confirmed in matched analyses, which showed that serum creatinine concentrations were different in White Europeans, Black Europeans and Black Africans for the same measured GFR, age, sex and body mass index. Creatinine differences were more relevant in males. CONCLUSION: In a European and African cohort, the performances of CKD-EPIAS remain suboptimal. The EKFC equation, using usual or dedicated population-specific Q-values, presents the best performance in the whole age range in the European and African populations included in this study.","[en] ",""

Cystatin C–Based Equation to Estimate GFR without the Inclusion of Race and Sex

BACKGROUNDThe accuracy of estimation of kidney function with the use of routine metabolic tests, such as measurement of the serum creatinine level, has been controversial. The European Kidney Function Consortium (EKFC) developed a creatinine-based equation (EKFC eGFRcr) to estimate the glomerular filtration rate (GFR) with a rescaled serum creatinine level (i.e., the serum creatinine level is divided by the median serum creatinine level among healthy persons to control for variation related to differences in age, sex, or race). Whether a cystatin C–based EKFC equation would increase the accuracy of estimated GFR is unknown.METHODSWe used data from patients in Sweden to estimate the rescaling factor for the cystatin C level in adults. We then replaced rescaled serum creatinine in the EKFC eGFRcr equation with rescaled cystatin C, and we validated the resulting EKFC eGFRcys equation in cohorts of White patients and Black patients in Europe, the United States, and Africa, according to measured GFR, levels of serum creatinine and cystatin C, age, and sex.RESULTSOn the basis of data from 227,643 patients in Sweden, the rescaling factor for cystatin C was estimated at 0.83 for men and women younger than 50 years of age and 0.83+0.005×(age–50) for those 50 years of age or older. The EKFC eGFRcys equation was unbiased, had accuracy that was similar to that of the EKFC eGFRcr equation in both White patients and Black patients (11,231 patients from Europe, 1093 from the United States, and 508 from Africa), and was more accurate than the Chronic Kidney Disease Epidemiology Collaboration eGFRcys equation recommended by Kidney Disease: Improving Global Outcomes. The arithmetic mean of EKFC eGFRcr and EKFC eGFRcys further improved the accuracy of estimated GFR over estimates from either biomarker equation alone.CONCLUSIONSThe EKFC eGFRcys equation had the same mathematical form as the EKFC eGFRcr equation, but it had a scaling factor for cystatin C that did not differ according to race or sex. In cohorts from Europe, the United States, and Africa, this equation improved the accuracy of GFR assessment over that of commonly used equations

Performance of Creatinine-Based Equations to Estimate Glomerular Filtration Rate in White and Black Subjects From Europe, Brazil and Africa

Abstract BACKGROUND AND AIMS Current Glomerular filtration rate (GFR) estimating equations based on serum creatinine are facing increased criticism due to the inclusion of a race correction in black Americans with the CKD-EPI equation (CKD-EPIASR, A = Age, S = Sex, R = Race). A new equation without race (CKD-EPIAS) has been proposed. However, this equation was developed mainly from US cohorts. The performance of this new equation has been poorly compared with current European-developed creatinine-based equations, i.e. the Lund-Malmö Revised (LMR), and the new European Kidney Function Consortium (EKFC) METHOD Data from subjects over 18 years, representing 11 cohorts from Europe (previously described as the EKFC dataset, n = 13 856), and enhanced with data from Brazil (n = 100), France (n = 4429) and Africa [Democratic Republic of Congo (DRC) and Côte d'Ivoire, n = 508] were considered (n = 18 893 for the whole cohort). The EKFC cohort was considered as non-black population. All data from Africa derived from black individuals. From France, 964 subjects were self-reported as black (=Blacks from Paris). Measured GFR as a reference method and IDMS creatinine results were available. Median bias (eGFR—mGFR) with 95% confidence intervals (CI), imprecision (interquartile range: IQR), and P30 accuracy (percentage of eGFR-values within ± 30% of mGFR) with 95% CI were calculated. RESULTS Results are summarized in Table. CONCLUSION The new CKD-EPIAS has been launched in the USA for societal reasons and is now recommended by US guidelines. However, in Europe and Africa, its performance was suboptimal. The EKFC equation, using the usual Q values, or population-specific Q values (when available), displays the best performance over the whole age range for populations in Europe and Africa

Synergies en océanographie opérationnelle: le besoin intrinsèque et permanent d'observations océaniques

International audienceOperational oceanography can be described as the provision of routine oceanographic information needed for decision-making purposes. It is dependent upon sustained research and development through the end-to-end framework of an operational service, from observation collection to delivery mechanisms. The core components of operational oceanographic systems are a multi-platform observation network, a data management system, a data assimilative prediction system, and a dissemination/accessibility system. These are interdependent, necessitating communication and exchange between them, and together provide the mechanism through which a clear picture of ocean conditions, in the past, present, and future, can be seen. Ocean observations play a critical role in all aspects of operational oceanography, not only for assimilation but as part of the research cycle, an