Clorose férrica induzida pelo calcário

Iron chlorosis is one of the most common and difficult to control problems in crops grown on calcareous soils. In alkaline soils, which represent one third of the Earth surface, the bicarbonate ion prevails and is a major induction factor of iron chlorosis. As a result, alkalinity limits Fe bioavailability in the soil solution, Fe reduction and assimilation, as well as transport and uptake within the plant. Due to this nutritional imbalance, plants develop different response strategies which are not entirely successful on calcareous soils. In consequence, yield, fruit quality and harvesting season are negatively affected. Preventing and treating iron chlorosis is highly costly, but is inevitable, in order to ensure crop sustainability in regions where soil calcium carbonate and aridity are limiting factors. In this work, we present a short overview of Fe dynamics in calcareous soils and its influence on crop productivit

Prediction of wide-sense stationary quaternion random signals

An efficient widely linear prediction algorithm is introduced for the class of wide-sense stationary quaternion signals. Specifically, using second order statistics information in the quaternion domain, a multivariate Durbin-Levison-like algorithm is derived. The proposed solution can be applied under a very general formulation of the problem, allowing for the estimation of a function of the quaternion signal which is observed through a system with both additive/multiplicative noises. © 2013 Elsevier B.V. All rights reserved

Prediction of wide-sense stationary quaternion random signals

An efficient widely linear prediction algorithm is introduced for the class of wide-sense stationary quaternion signals. Specifically, using second order statistics information in the quaternion domain, a multivariate Durbin-Levison-like algorithm is derived. The proposed solution can be applied under a very general formulation of the problem, allowing for the estimation of a function of the quaternion signal which is observed through a system with both additive/multiplicative noises. © 2013 Elsevier B.V. All rights reserved