Matthias Schäfer

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The floor plate is a signaling center in the ventral neural tube of vertebrates with important functions during neural patterning and axon guidance. It is composed of a centrally located medial floor plate (MFP) and a bilaterally positioned lateral floor plate (LFP). While the role of the MFP as source of signaling molecules like, e.g., Sonic Hedgehog (Shh)(More)
The ventral neural tube of vertebrates consists of distinct neural progenitor domains positioned along the dorsoventral (DV) axis that develop different types of moto- and interneurons. Several signalling molecules, most notably Sonic Hedgehog (Shh), retinoic acid (RA) and fibroblast growth factor (FGF) have been implicated in the generation of these(More)
The medial floor plate (MFP) organizes the specification of neurons and outgrowth of axons in the ventral spinal cord of vertebrates. We show that the growth factor Midkine-a, expressed in the paraxial mesoderm, is required for formation of the MFP in zebrafish. Our epistatic analyses demonstrate that development of MFP comprises two independent sequential(More)
In this paper, we investigate moment methods from a general point of view using an operator notation. This theoretical approach lets us explore the moment closure problem in more detail. This gives rise to a new idea, proposed in [14, 15], of how to improve the well-known PN approximations. We systematically develop a diffusive correction to the PN(More)
The steady-state simplified P N approximation to the radiative transport equation has been successfully applied to many problems involving radiation. Recently, time-dependent simplified P N equations have been derived by an asymptotic analysis similar to the asymptotic derivation of the steady-state SP N equations [7]. In this paper, we present(More)
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