the significance of spatial heterogeneity in understanding ecological processes has been recognized long ago. one of the earliest expressions of this recognition is the habitat heterogeneity hypothesis that links spatial  heterogeneity to niche vegetation patterns formation and species coexistence. yet, an  important if not crucial  aspect of landscape heterogeneity has escaped deep considerati...

Hierarchical processing is key to understanding vision. The visual system consists of hierarchically organized distinct anatomical areas functionally specialized for processing different aspects of a visual object (Felleman and Van Essen, 1991). These visual areas are interconnected through ascending feedforward projections, descending feedback projections, and projections from neural structure...

Although the exact details are disputed, it is well established that propagating waves of increased intracellular free Ca2+ concentration arise from a positive feedback or autocatalytic mechanism whereby Ca2+ stimulates its own release. Most previous modeling of the propagation of Ca2+ waves has assumed that the sites of autocatalytic Ca2+ release, the activation sites, are homogeneously distri...

abstract the extent to which teachers’ written corrective feedback (wcf) is conducive to esl learners’ improvement has been discussed since truscott’s claim in 1996. the mentioned debate continues because there has been lots of contrastive research studies with different results. this paper presents the results of a 2-month study of the effectiveness of wcf to 65 low intermediate iranian learne...

in this paper, a new approach to modify cable tension measuring mechanism is described; furthermore, the constructed boards which amplify load cell output are introduced. this approach has some advantages including of providing feedback for motors, evaluating the robot’s ultimate load carrying capacity, improving the motor control system and estimating the vibrating deflections of the end effec...