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Zinc has been suggested to act as an intracellular signaling molecule due to its regulatory effects on numerous protein targets including enzymes, transcription factors, ion channels, neurotrophic factors, and postsynaptic scaffolding proteins. However, intracellular zinc concentration is tightly maintained at steady levels under natural physiological conditions. Dynamic changes in intracellular...
In this paper, we introduce a sparse direction-of-arrival (DOA) estimation algorithm for sensor arrays presenting multiple scales of spatial invariance. We exploit the Khatri-Rao structure of the over-complete steering vector dictionary, corresponding to this array geometry, in order to devise a computationally efficient sparse estimation approach. This approach is based on an iterative refinement...
Summary The relative importance of mechanisms explaining the invasiveness and dominance of alien plant species remains a subject of active debate. Diffuse knapweed has been identified as a strong competitor capable of using allelopathic chemicals to achieve dominance in plant communities that have not coevolved with this species. Positive feedbacks with soil biota may further enhance the competitive...
In recent radio-communication applications, receivers may be jammed by high power unwanted signals. In this case, the received signal can be considered as the sum of a strong unwanted signal and a very weak target signal. Even though the two signals don't overlap in the frequency domain, the processing of the weak signal becomes very hard as it can be vanished at the output of the Analog Digital Converter...
Diffuse knapweed (Centaurea diffusa) is a noxious non-native forb that is currently invading and dominating western North American grasslands. We established a series of fertilization, reverse fertilization, and removal experiments in grasslands east of the Colorado Front Range, USA, to examine the response of C. diffusa and the rest of the grassland community to changes in nutrient availability....
Changes in competitive interactions under conditions of enhanced resource availability could explain the invasion success of some problematic plant species. For one invader of North American grasslands, Centaurea diffusa (diffuse knapweed), we test three hypotheses: (1) under ambient (high resource) conditions, C. diffusa is better able to tolerate competition from the resident community (competitive...
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