Search of a gravitational wave background in timing residuals of PSR 1937 21: minimal model and upper limits on Omega_gr

International audienceAlthough many phenomena can account for pulsar timing residuals, previous upper limits on the amplitude Omega_gr of a gravitational wave background were all obtained with the same decomposition into a measurement noise with known variance and a gravitational noise parametrized by Omega_gr. The justification of this minimal model (MM) is its ability to provide, on average over an infinite set of measurements, the highest upper limits on Omega_gr compared with other models. Keeping with this model, and using free-access Arecibo data concerning PSR 1937 21, we derive a set of 157 estimators of Omega_gr and obtain the 95 per cent confidence upper limit of 1.7x10^-7 using a Bayesian method. We also show evidence of a third term in the residuals (97 per cent confidence), which questions the adequacy of the MM

Integrated-Transformer-Based Impedance Matching Method: Impedance Matching With Transformers

Impedance matching is a critical aspect of any RF or millimeter-wave (mm-wave) design. Although historically addressed with transmission lines or discrete elements, it can also be implemented with integrated transformers as their quality factors now reach decent values (approximately 10–20) at high frequencies (used at 77 GHz in this article) due to the thicker upper metal layers present in most integrated stacks

Baseband TIA Design Using Inversion Coefficient MOSFET Model in CMOS 28nm

This paper presents a design methodology to size a transimpedance amplifier for an automotive radar receiver. Based on the Enz-Krummenacher-Vittoz (EKV) MOSFET model, it presents the essential equations to develop a small-signal model featuring a limited number of parameters, which can be exploited to quickly explore the different design optimums of a circuit. Post-layout simulations are presented to validate the model and the methodology. The designed TIA presents a gain of 65 dBΩ, a bandwidth of 80 MHz, an input impedance of 74 Ω and input-referred noise of 50 yA2.Hz−1

"BioMolChem", une méthode pour évaluer l'etat des défenses de la vigne : du gène au champ

National audienceUne méthode d’évaluation de l’état des défenses de la vigne a été développée au niveau biologique (inhibition de croissance), moléculaire (expression de gènes impliqués dans les défenses) et biochimique (analyses qualitatives et quantitatives des polyphénols), nommée "BioMolChem". La méthode "BioMolChem" permet d’établir des corrélations préliminaires entre l’expression des gènes de défense et la présence de certains stilbènes connus ou inconnus avec le niveau de protection des feuilles ou des grappes, selon les composantes de l’interaction plante-pathogène (variabilité inter- et intra-spécifique des agents pathogènes, variabilité génétique de la vigne et utilisation de différents produits éliciteurs). Ainsi est-il possible de disposer de ces indicateurs de défenses pour évaluer l’état de défense de la plante