Search results for "organizing centre"
showing 3 items of 3 documents
Symmetry Breaking and Establishment of Dorsal/Ventral Polarity in the Early Sea Urchin Embryo
2015
The mechanisms imposing the Dorsal/Ventral (DV) polarity of the early sea urchin embryo consist of a combination of inherited maternal information and inductive interactions among blastomeres. Old and recent studies suggest that a key molecular landmark of DV polarization is the expression of nodal on the future ventral side, in apparent contrast with other metazoan embryos, where nodal is expressed dorsally. A subtle maternally-inherited redox anisotropy, plus some maternal factors such as SoxB1, Univin, and p38-MAPK have been identified as inputs driving the spatially asymmetric transcription of nodal. However, all the mentioned factors are broadly distributed in the embryo as early as no…
Interno, Esterno, Frontiera. Note sulla Topologia dei Domini Nozionali
2014
This article examines a fundamental metalinguistic construction of the theory of enunciative operations: the Notional Domain. In particular, we try to explain some particular topological concepts on which this construction is based and we try to show the key role they play in the description of some basic linguistic operations: "fragmentation" and "construction of existence"
From Topology to Quasi-Topology. The Complexity of the Notional Domain
2016
This article examines a fundamental metalinguistic construction of the theory of enunciative operations: the notional domain. In particular, we try to explain some elementary topological concepts on which this construction is based and we try to show the key role they play in the description of some basic linguistic operations.