External validation of a prediction model for estimating fat mass in children and adolescents in 19 countries: individual participant data meta-analysis

Objective To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings. Design Individual participant data meta-analysis. Setting 19 countries. Participants 5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment). Main outcome measures The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R2, calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves. Results The model showed good predictive ability in non-UK populations of children and adolescents, providing R2 values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were <4 kg in 17 of the 19 settings. Pooled values (95% confidence intervals) of R2, calibration slope, and calibration-in-the-large were 88.7% (85.9% to 91.4%), 0.98 (0.97 to 1.00), and 0.01 (−0.02 to 0.04), respectively. Heterogeneity was evident in the R2 and calibration-in-the-large values across settings, but not in the calibration slope. Model performance did not vary markedly between boys and girls, age, ethnicity, and national income groups. To further improve the accuracy of the predictions, the model equation was recalibrated for the intercept in each setting so that country specific equations are available for future use. Conclusion The UK based prediction model, which is based on readily available measures, provides predictions of childhood fat-free mass, and hence fat mass, in a range of non-UK settings that explain a large proportion of the variability in observed fat-free mass, and exhibit good calibration performance, especially after recalibration of the intercept for each population. The model demonstrates good generalisability in both low-middle income and high income populations of healthy children and adolescents aged 4-15 years

Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota)

Compared to the higher fungi (Dikarya), taxonomic and evolutionary studies on the basal clades of fungi are fewer in number. Thus, the generic boundaries and higher ranks in the basal clades of fungi are poorly known. Recent DNA based taxonomic studies have provided reliable and accurate information. It is therefore necessary to compile all available information since basal clades genera lack updated checklists or outlines. Recently, Tedersoo et al. (MycoKeys 13:1--20, 2016) accepted Aphelidiomycota and Rozellomycota in Fungal clade. Thus, we regard both these phyla as members in Kingdom Fungi. We accept 16 phyla in basal clades viz. Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. Thus, 611 genera in 153 families, 43 orders and 18 classes are provided with details of classification, synonyms, life modes, distribution, recent literature and genomic data. Moreover, Catenariaceae Couch is proposed to be conserved, Cladochytriales Mozl.-Standr. is emended and the family Nephridiophagaceae is introduced

Over 10MHz Bandwidth Envelope-Tracking DC/DC Converter for Flexible High Power GaN Amplifiers

International audienceThis paper describes a fast envelope-tracking circuit capable of 10 MHz (up to 17.5 MHz) bandwidth based on RF GaN switching devices and 50 MHz switching frequency. The efficiency of the VHF converter is 84% to 90% which is comparable to a conventional DC/DC converter for spaceborne application. A demonstrator has been built and mated with a RF GaN HEMT output stage. The C/I measurement for 10-12W RF output power close to saturation show a linearity improvement by 5-8 dB and an efficiency improvement of up to 8 points when compared to the case of no tracking circuit

Fast switch mode power supply for DC power conversion

International audienc

Nutrition minérale et mycorhization contrôlée : compte rendu des travaux effectués en 1993

This document describes the 1993 programm about mediterranean forest seedling mineral nutrition and controlled mycorrhization. / Synthèse des travaux 1993 sur la nutrition minérale et la mycorhization contrôlée des plants forestiers méditerranéens

Nonlinear Electrothermal Modeling of packaged power GaN HEMT for the design of adaptive power amplifiers dedicated to reconfigurable telecom payloads

International audienceThe development of a new generation of transmitters at payload level operating with complex modulation scheme for telecom applications (i.e. multi-carrier operation) requires a high level of flexibility especially in terms of output power and efficiency of SSPA (Solid State Power Amplifier). This paper addresses the strategic emergent GaN power technology which is identified as the critical power technology for RF payload applications. Power flexibility is a critical identified need in transmitters at payload level since spacecrafts are built for a quite long period of 15 spaceflight years during which they are required to operate in non-constant traffic beams and variable coverage areas. This topic is extremely sensitive in power consumption of the global payload and researches focus on efficiency enhancement of SSPA assuming an output power dynamic range; as an example improving SSPA efficiency from 30 % to 35 % at constant output power would save DC power and decrease by 14 % the power consumption at payload level. The emergent GaN HEMTs (high electron mobility transistor) devices are promising for power amplification particularly at high frequency level, high output power which has been demonstrated by several papers 1, 2. This paper deals with the non linear modelling of commercialised GaN (Gallium Nitride) packaged transistor in L/S band which takes into account self-heating effects that appear mostly with high power GaN transistors, assuming that we do not have any information of the die size and package design

Analyse comparative des classes en commutation (F, F-1, E) pour l'amplification de puissance en technologie GaN

National audienceCette étude est effectuée en bande L à 1.5GHz (pour les applications spatiales) avec un modèle de transistor GaN 10W de la fonderie Eudyna. L'amplificateur optimisé en classe F présente un rendement en puissance ajoutée (PAE) de 72% associé à une puissance de 40.3dBm à 2dB de compression de gain. Pour celui optimisé en classe F-1, on obtient 74.5% de PAE et une puissance de 42.6dBm à 5dB de compression. Lors de l'analyse en classe E, on obtient 75% de PAE et une puissance de 41.1dBm à 3dB de compression de gain. La classe E apparaît alors comme la classe la mieux adaptée pour un compromis optimal en rendement et en puissance

Study and Design of High Efficiency Switch Mode GaN Power Amplifiers at L-band Frequency

International audienceActivities have been carried out to determine the best electrical operating conditions of GaN HEMT that enable maximum power added efficiency at L-Band for Switch Mode Power Amplifiers (class F, inverse class F and class E). Satellite Radio navigation applications (Galileo) are targeted. Maximization of power added efficiency is of prime importance to save DC power consumption, reduce self heating effects and improve reliability of power amplifiers. At 50V drain bias, a maximum power added efficiency (PAE) of 72% and 40.3 dBm output power (Pout) are obtained using class-F operating conditions at 2dB gain compression while a 75% PAE and 41.0 dBm Pout are obtained using class E at 3dB gain compression

Nutrition minerale et mycorhization controlee : compte rendu des travaux effectues en 1993

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : GR 1361 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc