Robust ANMF test using Huber's M-estimator

International audienceIn many statistical signal processing applications, the quality of the estimation of parameters of interest plays an important role. We focus in this paper, on the estimation of the covariance matrix. In the classical Gaussian context, the Sample Covariance Matrix (SCM) is the most often used, since it is the Maximum Likelihood estimate. It is easy to manage and has a lot of well-known statistical properties. However it may exhibit poor performance in context of non-Gaussian signals, contaminated or missing data. In that case M-estimators provide a good alternative. In this paper, we extend to the complex data case, a theoretical result already proposed by Tyler in the real data case, deriving the asymptotical distribution of any homogeneous functional of degree 0 of the M-estimates. Then, applying this result to the Adaptive Normalized Matched Filter (ANMF), we obtain a robust ANMF and give the relationship between its Probability of False Alarm (Pfa) and the detection threshold

Kinetic heterogeneity of non insulin-dependent diabetic patients: stable isotope study

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Plasma albumin concentration is a main factor in the control of lipoprotein metabolism: a kinetic study of two cases of analbuminemia

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Kinetic study of apoB-100 metabolism in non-insulin-dependent diabetics

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LDL heterogeneity in non-insulin-dependent diabetes mellitus (NIDDM) subjects

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Disorder of apolipoprotein AI metabolism in non insulin-dependent diabetes mellitus: a kinetic study

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Disorder of apolipoprotein AI metabolism in non insulin-dependent diabetes mellitus: a kinetic study

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The use of in vitro methods for blackpoint control and resistance in durum wheat (T. <em>turgidum</em> L. var. <em>durum</em>)

International audience"Utilisation de méthodes in vitro pour le contrôle de la moucheture et la résistance chez le blé dur'! II a été possible de faire apparaître à volonté la moucheture du grain de blé dur grâce à la réalisation de conditions de brumisation au champ, Dans ces conditions, le niveau de polyphénols pariétaux du grain est modifié. De plus, en conditions abiotiques confinées in vitro, des symptômes proches de la moucheture peuvent se développer même sur des grains mûrs stérilisés à I'autoclave. L'intensité de la réponse apparaît liée à la sensibilité au champ des génotypes à la moucheture. Aucun phénomène d'hypersensibilité du blé dur n'a pu être mis en relation avec la moucheture

Secondary metabolite effects of different cocoa genotypes on feeding preference of the mirid Sahlbergella singularis Hagl

International audienceSahlbergella singularis is a major insect pest of cocoa in Cameroon. Conventional insecticides remain the most widely used option for mirid control, which unfortunately have adverse effects on the environment and human health. Improved methods of controlling this species, both environmentally friendly and inexpensive to farmers, are requirements. Varietal control based on the selection of resistant and/or tolerant genotypes can be an interesting approach. Nonetheless, the role of secondary metabolites (SMs) in cocoa defense against mirids is poorly documented; yet, these compounds are reported to be key elements in plant defense against herbivores. For this purpose, SMs of twelve cocoa genotypes were identified and quantified, as well as their impact on food preference by mirids. Food preference was assessed through microtests measuring cocoa attractiveness and antixenosis toward mirids. The results showed that cocoa genotypes were differently accepted as food by mirids, with a significant preference for hybrid IMC60 x SNK605 and a non-preference for T60/887. The ten other cocoa genotypes showed intermediate results. Five SMs classes: alkaloids, flavonoids, polyphenols, saponins, and tannins were identified. Their rates varied between cocoa genotypes: polyphenols > alkaloids > flavonoids > tannins, and saponins. Cocoa genotypes with high total phenolic contents were significantly preferred by S. singularis (r(alpha) = 0.86, R-2 = 74.0%, P < 0.001), while those with low saponins contents were lowly accepted (r(alpha) = - 0.83, R-2 = 68.9%, P < 0.015), independently of the levels of other SMs. Given SMs high potential to affect mirid feeding behavior, analyzing cocoa SMs composition may help in early selection of resistant cocoa varieties against S. singularis