A new method to reconstruct the instantaneous convection pattern in the Earth's polar ionosphere is suggested. Plasma convection in the polar cap ionosphere is described as a hydrodynamic incompressible ̄ow. This description is valid in the region where the electric currents are ®eld aligned (and hence, the Lorentz body force vanishes). The problem becomes two-dimensional, and may be described ...

The activity patterns of most terrestrial animals are regarded as being primarily influenced by light, although other factors, such as sexual cycle and climatic conditions, can modify the underlying patterns. However, most activity studies have been limited to a single study area, which in turn limit the variability of light conditions and other factors. Here we considered a range of variables ...

We compare the zonal flow pattern in subsurface layers of the Sun with the distribution of surface magnetic features like sunspots and polar faculae. We demonstrate that in the activity belt, the butterfly pattern of sunspots coincides with the fast stream of zonal flows, although part of the sunspot distribution does spill over to the slow stream. At high latitudes, the polar faculae and zonal...

We propose an effective adaptive null-forming scheme for two nearby microphones in endfire orientation that are used in digital hearing aids and in many other hearing devices. This adaptive null-forming scheme is mainly based on an adaptive combination of two fixed polar patterns that act to make the null of the combined polar pattern of the system output always be toward the direction of the n...

Root formation in plants involves the continuous interpretation of positional cues. Physiological studies have linked root formation to auxins. An auxin response element displays a maximum in the Arabidopsis root and we investigate its developmental significance. Auxin response mutants reduce the maximum or its perception, and interfere with distal root patterning. Polar auxin transport mutants...

pollen grains of five olive cultivars (olea europaea l .) were examined, using scanning electron microscopy (sem) for identification purposes. four measurments, polar axis (p), equatorial diameter (e), p/e ratio and exine patterns were made. forty pollen grains of each cultivar were viewed before finally selecting a representative pollen grain. polar diameter ranged between 22.76 μm for the...

In the literature, it is often assumed, for example with respect to Hydra, that several Turing systems coexist and it is also assumed that maintaining the polar profile, even when the system increases in size, is important for the polarity of the final phenotype. It is shown here that in reality there is only one Turing system, Child's system. To obtain a complete polar individual or organ, whe...