Construction by description in discourse representation

This paper uses classical logic for a simultaneous description of the syntax and semantics of a fragment of English and it is argued that such an approach to natural language allows procedural aspects of linguistic theory to get a purely declarative formulation. In particular, it will be shown how certain construction rules in Discourse Representation Theory, such as the rule that indefinites create new discourse referents and definites pick up an existing referent, can be formulated declaratively if logic is used as a metalanguage for English. In this case the declarative aspects of a rule are highlighted when we focus on the model theory of the description language while a procedural perspective is obtained when its proof theory is concentrated on. Themes of interest are Discourse Representation Theory, resolution of anaphora, resolution of presuppositions, and underspecification.

Construction by Description in DRT

In this paper we want to argue that important parts of the DRT [Kam81, KR93] construction algorithm can in fact be given a purely declarative, logical formulation. In particular, procedural rules such as “introduce a new discourse referent into the universe of the DRS, ” or the requirement that a discourse referent must be “old ” (i.e. accessible from the current position) have natural declarative formulations within the ‘Logical Description Grammars ’ of [Mus01], an approach that uses logic for simultaneous description of syntax and semantics. This contrasts with earlier purely logical approaches to discourse semantics. For example, in Dynamic Predicate Logic [GS91] and related formalisms (including [Mus96]) it is necessary to assume that syntactic input to the semantic component comes with an indexation representing anaphoric links occurring in that input. Constraints on anaphora resolution cannot easily be dealt with in such theories. A Logical Description Grammar (LDG) is a logical theory G, set up with the intention that whenever we have a sentence OT stating some simple observabl

Glutaminyl cyclase is an enzymatic modifier of the CD47- SIRPα axis and a target for cancer immunotherapy

Cancer cells can evade immune surveillance through the expression of inhibitory ligands that bind their cognate receptors on immune effector cells. Expression of programmed death ligand 1 in tumor microenvironments is a major immune checkpoint for tumor-specific T cell responses as it binds to programmed cell death protein-1 on activated and dysfunctional T cells 1 . The activity of myeloid cells such as macrophages and neutrophils is likewise regulated by a balance between stimulatory and inhibitory signals. In particular, cell surface expression of the CD47 protein creates a ‘don’t eat me’ signal on tumor cells by binding to SIRPα expressed on myeloid cells 2–5 . Using a haploid genetic screen, we here identify glutaminyl-peptide cyclotransferase-like protein (QPCTL) as a major component of the CD47-SIRPα checkpoint. Biochemical analysis demonstrates that QPCTL is critical for pyroglutamate formation on CD47 at the SIRPα binding site shortly after biosynthesis. Genetic and pharmacological interference with QPCTL activity enhances antibody-dependent cellular phagocytosis and cellular cytotoxicity of tumor cells. Furthermore, interference with QPCTL expression leads to a major increase in neutrophil-mediated killing of tumor cells in vivo. These data identify QPCTL as a novel target to interfere with the CD47 pathway and thereby augment antibody therapy of cancer