The environmental conditions which contributed to the formation of the notorious quaternary deposits of freshwater sponge spicules in karstic lentic environments in Brazil have been subject of some speculation. No investigation has yet been conducted to test whether these deposits currently originate in karstic lakes. To provide for such an investigation, Serra Negra Lake, which is formed on an...

Anterior arch of the atlas vertebra is known to exhibit various developmental anomalies. Bony outgrowths, osteophytes, clefts and aplasia of the anterior and posterior arches of the atlas have received special attention by research workers. To the best of our knowledge, not many osteological studies have defined the spicules on the anterior arch of the atlas. The present study describes an abno...

We compare simultaneous sequences of Hα and He ii 304Å images near the solar limb. We propose to distinguish polar surges and giant spicules (macrospicules), among the He ii structures observed beyond the solar limb. Polar surges have a complex structure when observed in Hα and an erup-tive nature, reminiscent of normal surges in small scale. Giant spicules are simple spikes, very narrow compar...

Three Ektaphelenchus species with unusual spicules are redescribed. Ektaphelenchus obtusus and E. riograndensis are redescribed from newly discovered material in the collection of the USDA Forest Service RMRS. Lectotype slides are designated for both species. Ektaphelenchus obtusus is characterized by a set-off head, lips of unequal size, double rows of oocytes and spermatocytes, and a hooked s...

In this paper, we propose a new method for automatic extraction of breast mass spicules in 2-D mammography. Spicules are abnormal curvilinear structures which characterize most of malignant breast masses. They are important features for discrimination between benign and malignant masses. In our method, the curvilinear structures are first approximated by line segments derived from localized Rad...

Native cowhage spicules, and heat-inactivated spicules containing histamine or capsaicin, evoke similar sensations of itch and nociceptive sensations in humans. In ongoing studies of the peripheral neural mechanisms of chemical itch and pain in the mouse, extracellular electrophysiological recordings were obtained, in vivo, from the cell bodies of mechanosensitive nociceptive neurons in respons...

During mating behavior the Caenorhabditis elegans male must regulate periodic and prolonged protractor muscle contractions to insert his copulatory spicules into his mate. The protractors undergo periodic contractions to allow the spicules to reattempt insertion if a previous thrust failed to breach the vulva. When the spicule tips penetrate the vulva, the protractors undergo prolonged contract...

Despite its inherent mechanical fragility, silica is widely used as a skeletal material in a great diversity of organisms ranging from diatoms and radiolaria to sponges and higher plants. In addition to their micro- and nanoscale structural regularity, many of these hard tissues form complex hierarchically ordered composites. One such example is found in the siliceous skeletal system of the Wes...