The C. Elegans ROR receptor tyrosine kinase, CAM-1, non-autonomously inhibits the Wnt pathway

Inhibitors of Wnt signaling promote normal development and prevent cancer by restraining when and where the Wnt pathway is activated. ROR proteins, a class of Wnt-binding receptor tyrosine kinases, inhibit Wnt signaling by an unknown mechanism. To clarify how RORs inhibit the Wnt pathway, we examined the relationship between Wnts and the sole C. elegans ROR homolog, cam-1, during C. elegans vulval development, a Wnt-regulated process. We found that loss and overexpression of cam-1 causes reciprocal defects in Wnt-mediated cell-fate specification. Our molecular and genetic analyses revealed that the CAM-1 extracellular domain (ECD) is sufficient to non-autonomously antagonize multiple Wnts, suggesting that the CAM-1/ROR ECD sequesters Wnts. A sequestration model is supported by our findings that the CAM-1 ECD binds to several Wnts in vitro. These results demonstrate how ROR proteins help to refine the spatial pattern of Wnt activity in a complex multicellular environment

C. elegans BED domain transcription factor BED-3 controls lineage-specific cell proliferation during organogenesis

The control of cell division is critical to organogenesis, but how this control is achieved is not fully understood. We found that mutations in bed-3, encoding a BED Zn-finger domain transcription factor, confer a phenotype where a specific set of cell divisions during vulval organogenesis is lost. Unlike general cell cycle regulators in Caenorhabditis elegans, the function of bed-3 is restricted to specific lineages. Transcriptional reporters suggest that bed-3 is expressed in a limited number of cell types including vulval cells whose divisions are affected in bed-3 mutants. A bed-3 mutation also affects the expression pattern of the cdh-3 cadherin gene in the vulva. The phenotype of bed-3 mutants is similar to the phenotype caused by mutations in cog-1 (Nkx6), a component of a gene regulatory network controlling cell type specific gene expression in the vulval lineage. These results suggest that bed-3 is a key component linking the gene regulatory network controlling cell-type specification to control of cell division during vulval organogenesis

Transmitting data over a communications channel

Techniques for transmitting data over a communications channel are generally described. A value of a property of an inverse of a channel matrix corresponding to the communications channel may be calculated and compared to a threshold value. If the value of the property a first one of greater than or less than the threshold value, at least one transmit message may be altered using a vector perturbation technique to generate data symbols and the data symbols may be precoded using a channel inversion technique to generate precoded data symbols. If the value of the property is the other of greater than or less than the threshold value, the at least one transmit message may be precoded using a channel inversion technique to generate precoded data symbols.Board of Regents, University of Texas Syste

A Sound Interpretation of Leśniewski's Epsilon in Modal Logic KTB

In this paper, we shall show that the following translation $I^M$ from the propositional fragment $\bf L_1$ of Leśniewski's ontology to modal logic $\bf KTB$ is sound: for any formula $\phi$ and $\psi$ of $\bf L_1$, it is defined as(M1) $I^M(\phi \vee \psi) = I^M(\phi) \vee I^M(\psi)$,(M2) $I^M(\neg \phi) = \neg I^M(\phi)$,(M3) $I^M(\epsilon ab) = \Diamond p_a \supset p_a . \wedge . \Box p_a \supset \Box p_b .\wedge . \Diamond p_b \supset p_a$,where $p_a$ and $p_b$ are propositional variables corresponding to the name variables $a$ and $b$, respectively. In the last, we shall give some comments including some open problems and my conjectures