The kaleidoscopic structures in the electron micrographs above are the bundles of microtubules (axonemes) found in moth and fly sperm tail flagella, shown in cross-section. The axonemes above show the pattern typical of cilia and flagella in insects and other arthropods: nine doublet microtubules surround a central pair of singlet microtubules, and each doublet is associated with a singlet 'acc...

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T N-methyl-D-aspartate (NMDA)type glutamate receptor is one of three major classes of receptors for glutamate, the principle excitatory neurotransmitter in the central nervous system. It plays a key role in learning and in the formation of memories by acting as a ‘‘coincidence detector’’ that initiates changes in synaptic strength that lead to the formation of new neural networks (1). It is als...

Studies of spatial summation often use sinusoidal gratings with blurred edges. When the envelope is elongated (i) along the grating stripes and (ii) at right angles to the grating stripes, we refer to the stimuli as skunk-tails and tiger-tails respectively. Previous work [Polat & Tyler, 1999; Vision Research, 39, 887-895.] has found that sensitivity to skunk-tails is greater than for tiger-tail...

The diagnosis of curable, secondary causes of hypertension is a satisfying but challenging aspect, for both patient and doctor, of the clinical management of hypertension. They are probably under-recognized, and the enthusiasm to look for causes is blunted by low pickup rates in unselected patients. Young age encourages a search more because the alternative is many decades of drug treatment tha...