the aim of this investigation was to compare the level and the pattern of attention demands of a volleyball jumping serve using a probe reaction time (rt) technique. 14 junior elite volleyball players performed 60 jumping serves (js) with their preferred hand. jumping serve was performance as the primary task and verbal rt that was administered in four probe positions (pp) as secondary task. re...

The neuroectoderm arises during gastrulation as a population of undifferentiated proliferating neuroepithelial cells. As development continues, neuroepithelial cells leave the cell cycle and differentiate into neurons and glia of the functioning central nervous system. What processes establish the spatial distribution of proliferating neuroepithelial cells? To investigate this question, zic2a w...

During gastrulation, diffusible "organizer" signals, including members of the TGFbeta Nodal subfamily, pattern dorsal mesoderm and the embryonic axes. Simultaneously, negative regulators of these signals, including the Nodal inhibitor Lefty, an atypical TGFbeta factor, are induced by Nodal. This suggests that Lefty-dependent modulation of organizer signaling might regulate dorsal mesoderm patte...

Specialized groups of cells known as organizers govern the establishment of cell type diversity across cellular fields. Segmental patterning within the Drosophila embryonic epidermis is one paradigm for organizer function. Here cells differentiate into smooth cuticle or distinct denticle types. At parasegment boundaries, cells expressing Wingless confront cells co-expressing Engrailed and Hedge...

During gastrulation in Xenopus convergence and extension movements, mediated by mediolateral intercalations, are the driving force for early neural plate morphogenesis. Here we show that the winged helix transcriptional regulator, Xfd-12' is dynamically expressed in medial neural plate precursors that undergo convergence and extension movements. These medial neuraxial progenitors are specified ...

Recent revisions to the Xenopus fate map challenge the interpretation of previous maps and current models of amphibian axial patterning (Lane, M.C., Smith, W.C., 1999. The origins of primitive blood in Xenopus: implications for axial patterning. Development 126 (3), 423-434.; Lane, M.C., Sheets, M.D., 2000. Designation of the anterior/posterior axis in pregastrula Xenopus laevis. Dev. Biol. 225...

This study investigated if different response formats (test methods) measure reading comprehension of expository text differently. The study was conducted with 48 semester 6 TESL students at a university in Selangor, Malaysia. These students received an expository passage having descriptive rhetorical structure followed by three response formats, namely, incomplete outline, graphic organizer, a...