in order to study the stratigraphic of sedimentary deposits of the cenomanian in kopeh dagh, the taghiabad section was selected. in the eastern kopeh dagh, the upper part of aitamir formation has this time range characteristic. the upper part of this formation includes shale and glauconitic sandstones and contains variety of ammonite fauna. ten genera and species of ammonites are found inside t...

The Cathaysia Block is located in southeastern part of South China, which situates in the west Pacific subduction zone. It is thought to have undergone a compression-extension transition of the continental crust during Mesozoic-Cenozoic during the subduction of Pacific Plate beneath Eurasia-Pacific Plate, resulting in extensive magmatism, extensional basins and reactivation of fault systems. Al...

The nature of the surface of Venus is one of the keys to answering fundamental questions about the origin and evolution of the terrestrial planets and is of critical significance to comparative planetology. The last 25 years of solar system exploration have provided unprecedented views of the Earth, Moon, Mars, and Mercury. These views have shown that the smaller terrestrial planetary bodies (t...

Iceland is located where the asthenosperic flow under the the NE Atlantic plate boundary interacts and mixes with a deep-seated mantle plume. The buoyancy of the Iceland plume leads to dynamic uplift of the Iceland plateau, and high volcanic productivity over the plume produces a thick crust. (Fig.1). The Greenland-Færöy ridge represents the Icland plume track through the history of the NE Atla...

Ranidae is a large anuran group with a nearly cosmopolitan distribution. We investigated the phylogenetic relationships and early biogeographic history of ranid frogs, using 104 representatives of all subfamilies and families, sampled from throughout their distribution. Analyses of approximately 1570 bp of nuclear gene fragments (Rag-1, rhod, Tyr) and approximately 2100 bp of the mitochondrial ...

Patterns of neuronal differentiation and axon outgrowth were examined in regenerated neural tissue of the hindbrain of the chicken embryo. Specific regions of the hindbrain neural tube corresponding to identified rhombomeres were selectively removed unilaterally by microsurgery. Of the embryos that survived, about 35% exhibited regulative regeneration, wherein the missing hemi-rhombomere was re...