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We studied the organization of the somatosensory cortex in proficient Braille readers, recording somatosensory evoked potentials (SEPs) in 10 subjects and using transcranial magnetic stimulation (TMS) in five subjects, and compared the results with those of 15 control subjects. Somatosensory evoked potentials were elicited by a focal electrical stimulus to the tip of the index finger and recorded from a contralateral 4 x 4 grid of scalp electrodes centred around C3' and C4'. Transcranial magnetic stimulation, with an 8-shaped coil centred over the same scalp positions, was delivered simultaneously with, and at different intervals after, the finger stimulus. The results of the right index (reading) finger in Braille readers were compared with those of their left index (non-reading) finger and of the right and left index fingers of the control subjects. The scalp areas from which we recorded N20 and P22 components of the SEP with an amplitude of at least 70% of the maximal amplitude recorded in each trial were significantly larger in SEPs evoked from the reading fingers. Detection of the stimulus applied to the reading finger was blocked by TMS delivered over a larger contralateral scalp area and during a longer time window after the stimulus. These experiments suggest that reading Braille is associated with expansion of the sensorimotor cortical representation of the reading finger.

We present predictions for numerous statistics related to the presence of voids in the distribution of galaxies in a cold dark matter model of structure formation using a semi-analytic model of galaxy formation. Our study is able to probe galaxies with masses as low as 10 9 h −1 M corresponding to absolute magnitudes of M b J − 5 log h = −18.1 and M r − 5 log h = −18.7. We quantify the void and underdense probability functions, distributions of nearest-neighbour distances and void sizes and compute the density profiles of voids. These results are contrasted with the expectations for dark matter (and the difference examined in terms of the galaxy/dark matter biasing relation) and are compared with analytic predictions and observational data where available. The predicted void probability functions are consistent with those measured from the Centre for Astrophysics redshift surveys given the rather large uncertainties in this relatively small (for studies of voids) observational sample. The size of the observational sample is too small to probe the bias between galaxies and dark matter that we predict. We also examine the predicted properties of galaxies existing within voids and contrast these with the general galaxy population. Our predictions are aimed at forthcoming large galaxy redshift surveys that should for the first time provide statistically accurate measures of the void population.

We generalize results of Homma and Kim [J.

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For the Hermitian curve H dened over the nite eld F q 2 , we give a complete classication of Galois coverings of H of prime degree. The corresponding quotient curves turn out to be special cases of wider families of curves F q 2 -covered by H arising from subgroups of the special linear group SL (2; F q ) or from subgroups in the normaliser of the Singer group of the projective unitary group P G U (3; F q 2 ). Since curves F q 2 -covered by H are maximal over F q 2 , our results provide some classication and existence theorems for maximal curves having large genus, as well as several values for the spectrum of the genera of maximal curves. For every q 2 , both the upper limit and the second largest genus in the spectrum are known, but the determination of the third largest value is still in progress. A discussion on the \third largest genus problem" including some new results and a detailed account of current w ork is given. MIRAMARE { TRIESTE

Three 2,3,1',3'-tetraacyl- and two 2,3,3'-triacylsucroses, nicandroses A-E (1-5), were isolated from the fruits of Physalis nicandroides var. attenuata. The acyl groups in these new compounds were identified as decanoyl, isobutyryl, 2-methylbutanoyl, and acetyl. The structures of 1-5 were determined on the basis of NMR and MS analyses.