We present the results of a systematic, unbiased search for subpulse modulation of 187 pulsars performed with the Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands at an observing wavelength of 21 cm. Using new observations and archival WSRT data we have increased the list of pulsars that show the drifting subpulse phenomenon by 42, indicating that at least one in three pulsars exh...

A method for the analysis of nonstationary time series with multiple modes of behaviour is presented. In particular, it is not only possible to detect a switching of dynamics but also a less abrupt, time consuming drift from one mode to another. This is achieved by an unsu-pervised algorithm for segmenting the data according to the modes and a subsequent search through the space of possible dri...

As the Universe expands, redshift of distant sources changes with time. Here we discuss gravitational lensing phenomena that are consequence drift between lensed source, lens, and observer. When source is located very close to drifting caustics, a pair images could occur (or disappear) because cosmological expansion. Furthermore, systems act as signal converters drift. The angular position, mag...

Magnocellular (M-), but not parvocellular (P-), neurons of the macaque lateral geniculate nucleus (LGN) differ distinctively in their responses to counterphase-modulated and drifting gratings. Relative to stimulation with drifting gratings, counterphase modulation reduces the responses of M- cells in a band around 25 Hz, producing a "notch" in the temporal modulation transfer function (tMTF). T...

[1] We present experimental results on the snow drift in a turbulent boundary layer over a flat fresh snow-covered surface. Vertical profiles of mass flux and of the distribution of particle diameters were obtained by means of a pair of Snow Particle Counters parallel with measurements of the stream-wise velocity profile. The aim of the paper is to discuss current parameterizations of the verti...

The responses of lateral geniculate nucleus (LGN) cells in the common marmoset (Callithrix jacchus) to drifting luminance or cone isolating gratings of different spatial frequencies and contrasts were measured. The response noise, defined as the variability of the responses to single sweeps in the complex plane, was independent of stimulus contrast and spatial frequency but increased with incre...

Segregating a moving object from its visual context is particularly relevant for the control of smooth-pursuit eye movements. We examined the interaction between a moving object and a stationary or moving visual context to determine the role of the context motion signal in driving pursuit. Eye movements were recorded from human observers to a medium-contrast Gaussian dot that moved horizontally...

Repeated aircraft hazards in Alaska related to volcanic clouds have resulted in the use of a mobile C-band radar devoted to volcanic-cloud monitoring. The radar is located at Kenai, in range of several volcanoes in the Cook Inlet area. Three significant eruptions from the Crater Peak vent of Mount Spurr volcano (about 80 km from Kenai) in 1992 provided the first tests of the radar. The system c...