Andreas Fischer

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An iterative framework for solving generalized equations with nonisolated solutions is presented. For generalized equations with the structure 0 ∈ F(z) + T (z), where T is a multifunction and F is singlevalued, the framework covers methods that, at each step, solve subproblems of the type 0 ∈ A(z, s)+ T (z). The multifunction A approximates F around s.(More)
The Delta-Notch signaling pathway plays a central role in the development of most vertebrate organs. The Hey family of bHLH transcription factors are direct targets of Notch signaling. Loss of Hey2 in the mouse leads to cardiac defects with high postnatal lethality. We have now generated a mouse Hey1 knockout that has no apparent phenotypic defect. The(More)
Hes and Hey genes are the mammalian counterparts of the Hairy and Enhancer-of-split type of genes in Drosophila and they represent the primary targets of the Delta-Notch signaling pathway. Hairy-related factors control multiple steps of embryonic development and misregulation is associated with various defects. Hes and Hey genes (also called Hesr, Chf, Hrt,(More)
We consider nonlinear programs with inequality constraints, and we focus on the problem of identifying those constraints which will be active at an isolated local solution. The correct identification of active constraints is important from both a theoretical and a practical point of view. Such an identification removes the combinatorial aspect of the(More)
Nitrogen uptake and metabolism are central for vegetative and reproductive plant growth. This is reflected by the fact that nitrogen can be remobilized and reused within a plant, and this process is crucial for yield in most annual crops. A population of 146 recombinant inbred barley lines (F(8) and F(9) plants, grown in 2000 and 2001), derived from a cross(More)
Adequate response to low oxygen levels (hypoxia) by hypoxia inducible factor (HIF) is essential for normal development and physiology, but this pathway may also contribute to pathological processes like tumor angiogenesis. Here we show that hypoxia is an inducer of Notch signaling. Hypoxic conditions lead to induction of the Notch ligand Dll4 and the Notch(More)
Plant cell vacuoles may have either storage or degradative functions. Vegetative storage proteins (VSPs) are synthesized in response to wounding and to developmental switches that affect carbon and nitrogen sinks. Here we show that VSPs are stored in a unique type of vacuole that is derived from degradative central vacuoles coincident with insertion of a(More)
Mutations in Notch2, Jagged1 or homologs of the Hairy-related transcriptional repressor Hey2 cause congenital malformations involving the non-chamber atrioventricular canal (AVC) and inner curvature (IC) regions of the heart, but the underlying mechanisms have not been investigated. By manipulating signaling directly within the developing chick heart, we(More)