Validation of bioelectrical impedance analysis for body composition assessment in children with obesity aged 8-14y

BACKGROUND & AIMS: The aim was to generate a predictive equation to assess body composition (BC) in children with obesity using bioimpedance (BIA), and avoid bias produced by different density levels of fat free mass (FFM) in this population. METHODS: This was a cross-sectional validation study using baseline data from a randomized intervention trial to treat childhood obesity. Participants were 8 to 14y (n = 315), underwent assessments on anthropometry and BC through Air Displacement Plethysmography (ADP), Dual X-Ray Absorptiometry and BIA. They were divided into a training (n = 249) and a testing subset (n = 66). In addition, the testing subset underwent a total body water assessment using deuterium dilution, and thus obtained results for the 4-compartment model (4C). A new equation to estimate FFM was created from the BIA outputs by comparison to a validated model of ADP adjusted by FFM density in the training subset. The equation was validated against 4C in the testing subset. As reference, the outputs from the BIA device were also compared to 4C. RESULTS: The predictive equation reduced the bias from the BIA outputs from 14.1% (95%CI: 12.7, 15.4) to 4.6% (95%CI: 3.8, 5.4) for FFM and from 18.4% (95%CI: 16.9, 19.9) to 6.4% (95% CI: 5.3, 7.4) for FM. Bland-Altman plots revealed that the new equation significantly improved the agreement with 4C; furthermore, the observed trend to increase the degree of bias with increasing FM and FFM also disappeared. CONCLUSION: The new predictive equation increases the precision of BC assessment using BIA in children with obesity

Predicting site index from climate and soil variables for cork oak (Quercus suber L.) stands in Portugal

Site productivity, assessed through site index, was modelled using partial least squares regression as a function of soil and climatic variables. Two alternative models were developed: a full model, considering all available explanatory variables, and a reduced model, considering only variables that can be obtained without digging a soil pit. The reduced model was used for mapping the site index distribution in Portugal, on the basis of existing digital cartography available for the whole country. The developed models indicate the importance of water availability and soil water holding capacity for site index value distribution. Site index was related to climate, namely evaporation and frost, and soil characteristics such as lithology, soil texture, soil depth, thickness of the A horizon and soil classification. The variability of the estimated values within the map (9.5–16.8 m with an average value of 13.4 m) reflects the impact of soil characteristics on the site productivity estimation. These variables should be taken into consideration during the establishment of new plantations of cork oak, and management of existing plantations. Results confirm the potential distribution of cork oak in coastal regions. They also suggest the existence of a considerable area, located both North and South of the Tagus river, where site indices values of medium (]13;15]) to high (]15;17]) productivity classes may be expected. The species is then expected to be able to have good productivity along the northern coastal areas of Portugal, where presently it is not a common species but where, according to historical records, it occurred until the middle of the sixteenth century. The present research focused on tree growth. Cork growth and cork quality distribution needs to be further researched through the establishment of long term experimental sites along the distribution area of cork oak, namely in the central and northern coastal areas of the countryinfo:eu-repo/semantics/publishedVersio

Eco-epidemiological analysis of rickettsial seropositivity in rural areas of Colombia: A multilevel approach

ABSTARCT: Rickettsiosis is a re-emergent infectious disease without epidemiological surveillance in Colombia. This disease is generally undiagnosed and several deadly outbreaks have been reported in the country in the last decade. The aim of this study is to analyze the eco-epidemiological aspects of rickettsial seropositivity in rural areas of Colombia where outbreaks of the disease were previously reported. A cross-sectional study, which included 597 people living in 246 households from nine hamlets in two municipalities of Colombia, was conducted from November 2015 to January 2016. The survey was conducted to collect sociodemographic and household characteristics (exposure) data. Blood samples were collected to determine the rickettsial seropositivity in humans, horses and dogs (IFA, cut-off = 1/128). In addition, infections by rickettsiae were detected in ticks from humans and animals by real-time PCR targeting gltA and ompA genes. Data was analyzed by weighted multilevel clog-log regression model using three levels (person, household and hamlets) and rickettsial seropositivity in humans was the main outcome. Overall prevalence of rickettsial seropositivity in humans was 25.62% (95%CI 22.11-29.12). Age in years (PR = 1.01 95%CI 1.01-1.02) and male sex (PR = 1.65 95%CI 1.43-1.90) were risk markers for rickettsial seropositivity. Working outdoors (PR = 1.20 95%CI 1.02-1.41), deforestation and forest fragmentation for agriculture use (PR = 1.75 95%CI 1.51-2.02), opossum in peridomiciliary area (PR = 1.56 95%CI 1.37-1.79) and a high proportion of seropositive domestic animals in the home (PR20-40% vs 40% vs <20% = 3.14 95%CI 2.43-4.04) were associated with rickettsial seropositivity in humans. This study showed the presence of Rickettsia antibodies in human populations and domestic animals. In addition, different species of rickettsiae were detected in ticks collected from humans and animals. Our results highlighted the role of domestic animals as sentinels of rickettsial infection to identify areas at risk of transmission, and the importance of preventive measures aimed at curtailing deforestation and the fragmentation of forests as a way of reducing the risk of transmission of emergent and re-emergent pathogens

Definition of a temporal distribution index for high temporal resolution precipitation data over Peninsular Spain and the Balearic Islands: the fractal dimension; and its synoptic implications

Precipitation on the Spanish mainland and in the Balearic archipelago exhibits a high degree of spatial and temporal variability, regardless of the temporal resolution of the data considered. The fractal dimension indicates the property of self-similarity, and in the case of this study, wherein it is applied to the temporal behaviour of rainfall at a fine (10-min) resolution from a total of 48 observatories, it provides insights into its more or less convective nature. The methodology of Jenkinson & Collison which automatically classifies synoptic situations at the surface, as well as an adaptation of this methodology at 500 hPa, was applied in order to gain insights into the synoptic implications of extreme values of the fractal dimension. The highest fractal dimension values in the study area were observed in places with precipitation that has a more random behaviour over time with generally high totals. Four different regions in which the atmospheric mechanisms giving rise to precipitation at the surface differ from the corresponding above-ground mechanisms have been identified in the study area based on the fractal dimension. In the north of the Iberian Peninsula, high fractal dimension values are linked to a lower frequency of anticyclonic situations, whereas the opposite occurs in the central region. In the Mediterranean, higher fractal dimension values are associated with a higher frequency of the anticyclonic type and a lower frequency of the advective type from the east. In the south, lower fractal dimension values indicate higher frequency with respect to the anticyclonic type from the east and lower frequency with respect to the cyclonic type

Recent developments in genetics and medically assisted reproduction : from research to clinical applications

Two leading European professional societies, the European Society of Human Genetics and the European Society for Human Reproduction and Embryology, have worked together since 2004 to evaluate the impact of fast research advances at the interface of assisted reproduction and genetics, including their application into clinical practice. In September 2016, the expert panel met for the third time. The topics discussed highlighted important issues covering the impacts of expanded carrier screening, direct-to-consumer genetic testing, voiding of the presumed anonymity of gamete donors by advanced genetic testing, advances in the research of genetic causes underlying male and female infertility, utilisation of massively parallel sequencing in preimplantation genetic testing and non-invasive prenatal screening, mitochondrial replacement in human oocytes, and additionally, issues related to cross-generational epigenetic inheritance following IVF and germline genome editing. The resulting paper represents a consensus of both professional societies involved.Peer reviewe

Free-Living Turtles Are a Reservoir for Salmonella but Not for Campylobacter

Different studies have reported the prevalence of Salmonella in turtles and its role in reptile-associated salmonellosis in humans, but there is a lack of scientific literature related with the epidemiology of Campylobacter in turtles. The aim of this study was to evaluate the prevalence of Campylobacter and Salmonella in free-living native (Emys orbicularis, n=83) and exotic (Trachemys scripta elegans, n=117) turtles from 11 natural ponds in Eastern Spain. In addition, different types of samples (cloacal swabs, intestinal content and water from Turtle containers) were compared. Regardless of the turtle species, natural ponds where individuals were captured and the type of sample taken, Campylobacter was not detected. Salmonella was isolated in similar proportions in native (8.0±3.1%) and exotic (15.0±3.3%) turtles (p=0.189). The prevalence of Salmonella positive turtles was associated with the natural ponds where animals were captured. Captured turtles from 8 of the 11 natural ponds were positive, ranged between 3.0±3.1% and 60.0±11.0%. Serotyping revealed 8 different serovars among four Salmonella enterica subspecies: S. enterica subsp. enterica (n = 21), S. enterica subsp. salamae (n = 2), S. enterica subsp. diarizonae (n = 3), and S. enterica subsp. houtenae (n = 1). Two serovars were predominant: S. Thompson (n=16) and S. typhimurium (n=3). In addition, there was an effect of sample type on Salmonella detection. The highest isolation of Salmonella was obtained from intestinal content samples (12.0±3.0%), while lower percentages were found for water from the containers and cloacal swabs (8.0±2.5% and 3.0±1.5%, respectively). Our results imply that free-living turtles are a risk factor for Salmonella transmission, but do not seem to be a reservoir for Campylobacter. We therefore rule out turtles as a risk factor for human campylobacteriosis. Nevertheless, further studies should be undertaken in other countries to confirm these results.This work was supported by the Conselleria de Infraestructura, Territorio y Medio Ambiente for their assistance and financial support (Life09-Trachemys, Resolution 28/02/12 CITMA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Marín, C.; Ingresa-Capaccioni, S.; González Bodí, S.; Marco Jiménez, F.; Vega Garcia, S. (2013). Free-Living Turtles Are a Reservoir for Salmonella but Not for Campylobacter. PLoS ONE. 8(8):1-6. https://doi.org/10.1371/journal.pone.0072350S1688(2012). The European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food‐borne Outbreaks in 2010. EFSA Journal, 10(3). doi:10.2903/j.efsa.2012.2597Kapperud, G. (2003). Factors Associated with Increased and Decreased Risk of Campylobacter Infection: A Prospective Case-Control Study in Norway. American Journal of Epidemiology, 158(3), 234-242. doi:10.1093/aje/kwg139Mermin, J., Hutwagner, L., Vugia, D., Shallow, S., Daily, P., … Bender, J. (2004). Reptiles, Amphibians, and HumanSalmonellaInfection: A Population‐Based, Case‐Control Study. Clinical Infectious Diseases, 38(s3), S253-S261. doi:10.1086/381594De Jong, B., Andersson, Y., & Ekdahl, K. (2005). Effect of Regulation and Education on Reptile-associated Salmonellosis. Emerging Infectious Diseases, 11(3), 398-403. doi:10.3201/eid1103.040694NAKADAI, A., KUROKI, T., KATO, Y., SUZUKI, R., YAMAI, S., YAGINUMA, C., … HAYASHIDANI, H. (2005). Prevalence of Salmonella spp. in Pet Reptiles in Japan. Journal of Veterinary Medical Science, 67(1), 97-101. doi:10.1292/jvms.67.97Lafuente, S., Bellido, J. B., Moraga, F. A., Herrera, S., Yagüe, A., Montalvo, T., … Caylà, J. A. (2013). Salmonella paratyphi B and Salmonella litchfield outbreaks associated with pet turtle exposure in Spain. Enfermedades Infecciosas y Microbiología Clínica, 31(1), 32-35. doi:10.1016/j.eimc.2012.05.013Van PELT, W., de WIT, M. A. S., WANNET, W. J. B., LIGTVOET, E. J. J., WIDDOWSON, M. A., & van DUYNHOVEN, Y. T. H. P. (2003). Laboratory surveillance of bacterial gastroenteric pathogens in The Netherlands, 1991–2001. Epidemiology and Infection, 130(3), 431-441. doi:10.1017/s0950268803008392Havelaar, A. H., Haagsma, J. A., Mangen, M.-J. J., Kemmeren, J. M., Verhoef, L. P. B., Vijgen, S. M. C., … van Pelt, W. (2012). Disease burden of foodborne pathogens in the Netherlands, 2009. International Journal of Food Microbiology, 156(3), 231-238. doi:10.1016/j.ijfoodmicro.2012.03.029DOORDUYN, Y., VAN PELT, W., SIEZEN, C. L. E., VAN DER HORST, F., VAN DUYNHOVEN, Y. T. H. P., HOEBEE, B., & JANSSEN, R. (2007). Novel insight in the association between salmonellosis or campylobacteriosis and chronic illness, and the role of host genetics in susceptibility to these diseases. Epidemiology and Infection, 136(9), 1225-1234. doi:10.1017/s095026880700996xHAAGSMA, J. A., SIERSEMA, P. D., DE WIT, N. J., & HAVELAAR, A. H. (2010). Disease burden of post-infectious irritable bowel syndrome in The Netherlands. Epidemiology and Infection, 138(11), 1650-1656. doi:10.1017/s0950268810000531Allos, B. M., & Blaser, M. J. (1995). Campylobacter jejuni and the Expanding Spectrum of Related Infections. Clinical Infectious Diseases, 20(5), 1092-1101. doi:10.1093/clinids/20.5.1092Friedman, C. R., Hoekstra, R. M., Samuel, M., Marcus, R., Bender, J., … Shiferaw, B. (2004). Risk Factors for SporadicCampylobacterInfection in the United States: A Case‐Control Study in FoodNet Sites. Clinical Infectious Diseases, 38(s3), S285-S296. doi:10.1086/381598STUDAHL, A., & ANDERSSON, Y. (2000). Risk factors for indigenous campylobacter infection: a Swedish case-control study. Epidemiology and Infection, 125(2), 269-275. doi:10.1017/s0950268899004562NEIMANN, J., ENGBERG, J., MØLBAK, K., & WEGENER, H. C. (2003). A case–control study of risk factors for sporadic campylobacter infections in Denmark. Epidemiology and Infection, 130(3), 353-366. doi:10.1017/s0950268803008355DOORDUYN, Y., VAN DEN BRANDHOF, W. E., VAN DUYNHOVEN, Y. T. H. P., BREUKINK, B. J., WAGENAAR, J. A., & VAN PELT, W. (2010). Risk factors for indigenous Campylobacter jejuni and Campylobacter coli infections in The Netherlands: a case-control study. Epidemiology and Infection, 138(10), 1391-1404. doi:10.1017/s095026881000052xSchroter, M., Roggentin, P., Hofmann, J., Speicher, A., Laufs, R., & Mack, D. (2004). Pet Snakes as a Reservoir for Salmonella enterica subsp. diarizonae (Serogroup IIIb): a Prospective Study. Applied and Environmental Microbiology, 70(1), 613-615. doi:10.1128/aem.70.1.613-615.2004Van Meervenne, E., Botteldoorn, N., Lokietek, S., Vatlet, M., Cupa, A., Naranjo, M., … Bertrand, S. (2009). Turtle-associated Salmonella septicaemia and meningitis in a 2-month-old baby. Journal of Medical Microbiology, 58(10), 1379-1381. doi:10.1099/jmm.0.012146-0Williams, L. P. (1965). Pet Turtles as a Cause of Human Salmonellosis. JAMA: The Journal of the American Medical Association, 192(5), 347. doi:10.1001/jama.1965.03080180005001Feeley, J. C., & Treger, M. D. (1969). Penetration of Turtle Eggs by Salmonella braenderup. Public Health Reports (1896-1970), 84(2), 156. doi:10.2307/4593527Mermin, J., Hoar, B., & Angulo, F. J. (1997). Iguanas and Salmonella Marina Infection in Children: A Reflection of the Increasing Incidence of Reptile-associated Salmonellosis in the United States. PEDIATRICS, 99(3), 399-402. doi:10.1542/peds.99.3.399Rodgers, G. L., Long, S. S., Smergel, E., & Dampier, C. (2002). Salmonella Infection Associated With a Pet Lizard in Siblings With Sickle Cell Anemia: An Avoidable Risk. Journal of Pediatric Hematology/Oncology, 24(1), 75-76. doi:10.1097/00043426-200201000-00020Tu, Z.-C., Zeitlin, G., Gagner, J.-P., Keo, T., Hanna, B. A., & Blaser, M. J. (2004). Campylobacter fetus of Reptile Origin as a Human Pathogen. Journal of Clinical Microbiology, 42(9), 4405-4407. doi:10.1128/jcm.42.9.4405-4407.2004Hidalgo-Vila, J., Díaz-Paniagua, C., Pérez-Santigosa, N., de Frutos-Escobar, C., & Herrero-Herrero, A. (2008). Salmonella in free-living exotic and native turtles and in pet exotic turtles from SW Spain. Research in Veterinary Science, 85(3), 449-452. doi:10.1016/j.rvsc.2008.01.011Harris, J. R., Neil, K. P., Behravesh, C. B., Sotir, M. J., & Angulo, F. J. (2010). Recent Multistate Outbreaks of HumanSalmonellaInfections Acquired from Turtles: A Continuing Public Health Challenge. Clinical Infectious Diseases, 50(4), 554-559. doi:10.1086/649932Geue, L., & Löschner, U. (2002). Salmonella enterica in reptiles of German and Austrian origin. Veterinary Microbiology, 84(1-2), 79-91. doi:10.1016/s0378-1135(01)00437-0Sánchez-Jiménez, M. M., Rincón-Ruiz, P. A., Duque, S., Giraldo, M. A., Ramírez-Monroy, D. M., Jaramillo, G., & Cardona-Castro, N. (2011). Salmonella enterica in semi-aquatic turtles in Colombia. The Journal of Infection in Developing Countries, 5(05), 361-364. doi:10.3855/jidc.1126HEALTH SURVEY OF WILD AND CAPTIVE BOG TURTLES (CLEMMYS MUHLENBERGII) IN NORTH CAROLINA AND VIRGINIA. (2002). Journal of Zoo and Wildlife Medicine, 33(4), 311-316. doi:10.1638/1042-7260(2002)033[0311:hsowac]2.0.co;2Richards, J. M., Brown, J. D., Kelly, T. R., Fountain, A. L., & Sleeman, J. M. (2004). ABSENCE OF DETECTABLE SALMONELLA CLOACAL SHEDDING IN FREE-LIVING REPTILES ON ADMISSION TO THE WILDLIFE CENTER OF VIRGINIA. Journal of Zoo and Wildlife Medicine, 35(4), 562-563. doi:10.1638/03-070Hidalgo-Vila, J., Díaz-Paniagua, C., de Frutos-Escobar, C., Jiménez-Martínez, C., & Pérez-Santigosa, N. (2007). Salmonella in free living terrestrial and aquatic turtles. Veterinary Microbiology, 119(2-4), 311-315. doi:10.1016/j.vetmic.2006.08.012Acheson, D., & Allos, B. M. (2001). Campylobacter jejuni Infections: Update on Emerging Issues and Trends. Clinical Infectious Diseases, 32(8), 1201-1206. doi:10.1086/319760Briones, V., Tellez, S., Goyache, J., Ballesteros, C., del Pilar Lanzarot, M., Dominguez, L., & Fernandez-Garayzabal, J. F. (2004). Salmonella diversity associated with wild reptiles and amphibians in Spain. Environmental Microbiology, 6(8), 868-871. doi:10.1111/j.1462-2920.2004.00631.xMan, S. M. (2011). The clinical importance of emerging Campylobacter species. Nature Reviews Gastroenterology & Hepatology, 8(12), 669-685. doi:10.1038/nrgastro.2011.191Ugarte-Ruiz, M., Gómez-Barrero, S., Porrero, M. C., Álvarez, J., García, M., Comerón, M. C., … Domínguez, L. (2012). Evaluation of four protocols for the detection and isolation of thermophilic Campylobacter from different matrices. Journal of Applied Microbiology, 113(1), 200-208. doi:10.1111/j.1365-2672.2012.05323.xJeffrey, J. S., Tonooka, K. H., & Lozanot, J. (2001). Prevalence of Campylobacter spp. from Skin, Crop, and Intestine of Commercial Broiler Chicken Carcasses at Processing. Poultry Science, 80(9), 1390-1392. doi:10.1093/ps/80.9.1390Perko-Mäkelä, P., Isohanni, P., Katzav, M., Lund, M., Hänninen, M.-L., & Lyhs, U. (2009). A longitudinal study of Campylobacter distribution in a turkey production chain. Acta Veterinaria Scandinavica, 51(1). doi:10.1186/1751-0147-51-18Saelinger, C. A., Lewbart, G. A., Christian, L. S., & Lemons, C. L. (2006). Prevalence ofSalmonellaspp in cloacal, fecal, and gastrointestinal mucosal samples from wild North American turtles. Journal of the American Veterinary Medical Association, 229(2), 266-268. doi:10.2460/javma.229.2.266Chambers, D. L., & Hulse, A. C. (2006). Salmonella Serovars in the Herpetofauna of Indiana County, Pennsylvania. Applied and Environmental Microbiology, 72(5), 3771-3773. doi:10.1128/aem.72.5.3771-3773.2006Gaertner, J. P., Hahn, D., Jackson, J., Forstner, M. R. J., & Rose, F. L. (2008). Detection of Salmonellae in Captive and Free-Ranging Turtles Using Enrichment Culture and Polymerase Chain Reaction. Journal of Herpetology, 42(2), 223-231. doi:10.1670/07-1731.1Magnino, S., Colin, P., Dei-Cas, E., Madsen, M., McLauchlin, J., Nöckler, K., … Van Peteghem, C. (2009). Biological risks associated with consumption of reptile products. International Journal of Food Microbiology, 134(3), 163-175. doi:10.1016/j.ijfoodmicro.2009.07.001XIA, X., ZHAO, S., SMITH, A., MCEVOY, J., MENG, J., & BHAGWAT, A. (2009). Characterization of Salmonella isolates from retail foods based on serotyping, pulse field gel electrophoresis, antibiotic resistance and other phenotypic properties. International Journal of Food Microbiology, 129(1), 93-98. doi:10.1016/j.ijfoodmicro.2008.11.007Franco, A., Hendriksen, R. S., Lorenzetti, S., Onorati, R., Gentile, G., Dell’Omo, G., … Battisti, A. (2011). Characterization of Salmonella Occurring at High Prevalence in a Population of the Land Iguana Conolophus subcristatus in Galápagos Islands, Ecuador. PLoS ONE, 6(8), e23147. doi:10.1371/journal.pone.0023147Scheelings, T. F., Lightfoot, D., & Holz, P. (2011). PREVALENCE OF SALMONELLA IN AUSTRALIAN REPTILES. Journal of Wildlife Diseases, 47(1), 1-11. doi:10.7589/0090-3558-47.1.1Pasmans, F., Blahak, S., Martel, A., & Pantchev, N. (2008). Introducing reptiles into a captive collection: The role of the veterinarian. The Veterinary Journal, 175(1), 53-68. doi:10.1016/j.tvjl.2006.12.009Strohl, P., Tilly, B., Fremy, S., Brisabois, A., & Guerin-Faublee, V. (2004). Prevalence of Salmonella shedding in faeces by captive chelonians. Veterinary Record, 154(2), 56-58. doi:10.1136/vr.154.2.5

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way

With the most recent Gaia data release the number of sources with complete 6D phase space information (position and velocity) has increased to well over 33 million stars, while stellar astrophysical parameters are provided for more than 470 million sources, in addition to the identification of over 11 million variable stars. Using the astrophysical parameters and variability classifications provided in Gaia DR3, we select various stellar populations to explore and identify non-axisymmetric features in the disc of the Milky Way in both configuration and velocity space. Using more about 580 thousand sources identified as hot OB stars, together with 988 known open clusters younger than 100 million years, we map the spiral structure associated with star formation 4-5 kpc from the Sun. We select over 2800 Classical Cepheids younger than 200 million years, which show spiral features extending as far as 10 kpc from the Sun in the outer disc. We also identify more than 8.7 million sources on the red giant branch (RGB), of which 5.7 million have line-of-sight velocities, allowing the velocity field of the Milky Way to be mapped as far as 8 kpc from the Sun, including the inner disc. The spiral structure revealed by the young populations is consistent with recent results using Gaia EDR3 astrometry and source lists based on near infrared photometry, showing the Local (Orion) arm to be at least 8 kpc long, and an outer arm consistent with what is seen in HI surveys, which seems to be a continuation of the Perseus arm into the third quadrant. Meanwhile, the subset of RGB stars with velocities clearly reveals the large scale kinematic signature of the bar in the inner disc, as well as evidence of streaming motions in the outer disc that might be associated with spiral arms or bar resonances. (abridged

Gaia Early Data Release 3: Summary of the contents and survey properties

ABSTRACT: Context. We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Aims. A summary of the contents of Gaia EDR3 is presented, accompanied by a discussion on the differences with respect to Gaia DR2 and an overview of the main limitations which are present in the survey. Recommendations are made on the responsible use of Gaia EDR3 results. Methods. The raw data collected with the Gaia instruments during the first 34 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium and turned into this early third data release, which represents a major advance with respect to Gaia DR2 in terms of astrometric and photometric precision, accuracy, and homogeneity. Results. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (GBP ? GRP) colour are also available. The passbands for G, GBP, and GRP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Conclusions. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 per cent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30-40% for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, GBP, and GRP is valid over the entire magnitude and colour range, with no systematics above the 1% levelThe Gaia mission and data processing have financially been supported by ; the Spanish Ministry of Economy (MINECO/FEDER, UE) through grants ESP2016-80079-C2-1-R, ESP2016-80079-C2-2-R, RTI2018-095076-B-C21, RTI2018-095076-B-C22, BES-2016-078499, and BES-2017-083126 and the Juan de la Cierva formación 2015 grant FJCI-2015-2671, the Spanish Ministry of Education, Culture, and Sports through grant FPU16/03827, the Spanish Ministry of Science and Innovation (MICINN) through grant AYA2017-89841P for project “Estudio de las propiedades de los fósiles estelares en el entorno del Grupo Local” and through grant TIN2015-65316-P for project “Computación de Altas Prestaciones VII