Debt Contracts with ex-ante and ex-post Asymmetric Information: An Example

We consider a simple model of lending and borrowing combining two informational problems: adverse selection and costly state verification. Our analysis highlights the interaction between these two informational problems. We notably show that the higher the monitoring cost, the less discriminating the optimal menu of contracts is.debt contracts, diversity of opinions, screening, costly monitoring, pooling

Existence and monotonicity of optimal debt contracts in costly state verification models

This note gives a simple proof of the existence and monotonicity of optimal debt contracts in simple models of borrowing and lending with ex-post asymmetric information, risk-averse agents and heterogeneous beliefs. Our argument is based on the concept of nondecreasing rearrangement and on a supermodular version of Hardy-Littlewood inequality.

Optimal debt contracts and diversity of opinions: an extreme case of bunching

This paper studies optimal menus of debt contracts such as secured debentures or bonds, in the presence of diversity of opinions between borrowers and lenders. We first characterize incentive compatible contracts, then prove the existence of optimal debt contracts. Finally, we are able to explicitly characterize such optimal menus within a specific case: we notably show that borrowers optimally offer at most two contracts, which is an extreme case of bunching.debt contracts, heterogeneity of beliefs, multidimensional screening, bunching

Debt contracts with ex-ante and ex-post asymmetric information: an example.

We consider a simple model of lending and borrowing combining two informational problems: adverse selection and costly state verification. Our analysis highlights the interaction between these two informational problems. We notably show that the higher the monitoring cost, the less discriminating the optimal menu of contracts is.Debt contracts; Diversity of opinions; Screening; Costly monitoring; Pooling;

NMR resonance assignments of NarE, a putative ADP-ribosylating toxin from Neisseria meningitidis

NarE is a 16 kDa protein identified from Neisseria meningitidis, one of the bacterial pathogens responsible for meningitis. NarE belongs to the ADP-ribosyltransferase family and catalyses the transfer of ADP-ribose moieties to arginine residues in target protein acceptors. Many pathogenic bacteria utilize ADP-ribosylating toxins to modify and alter essential functions of eukaryotic cells. NarE was proposed to bind iron through a Fe–S center which is supposed to be implied in catalysis. We have produced and purified uniformly labeled 15N- and 15N/13C-NarE and assigned backbone and side-chain resonances using multidimensional heteronuclear NMR spectroscopy. These assignments provide the starting point for the three-dimensional structure determination of NarE and the characterization of the role of the Fe–S center in the catalytic mechanism

Production de domaines recombinants PRODH en vue de l'analyse structurale & Caractérisation de la région 51-160 de la protéine KIN17 humaine par RMN et Modélisation Moléculaire

Maintenance of the genomic integrity is crucial for all living organisms. Since cells are continuously submitted to genotoxic stresses that induce DNA damages, they have evolved sophisticated mechanisms to detect, signal the presence of, and repair these lesions. Among sources of DNA damage, UV radiation alters DNA structure and can cause mutations and chromosomal translocations. In humans, Nucleotide Excision Repair (NER) is an efficient way to remove DNA lesions induced by UV or ionizing radiation. NER inactivation leads to cell death and increase the susceptibility to develop diseases such as cancer and hereditary disorders. Among numerous proteins involved in the NER pathway, XPA and XPC can trigger the expression of several secondary genes such as KIN17 which encodes a 45 kDa protein. In order to elucidate the biological function of KIN17, biochemical and structural studies of its domains were performed. This thesis work focus on the region 51-160 of the human protein. NMR and Molecular Modelling studies showed that this region adopts a winged helix fold mainly know for its ability to bind nucleic acids. However, structure-activity relationships revealed that the Winged Helix of human KIN17 is not able to bind DNA or RNA. On the other hand, this domain exhibits a highly conserved surface involved in intramolecular interactions with the N-terminal region of the protein.Le maintien de l'intégrité du patrimoine génétique est essentiel à la survie des organismes vivants. Face aux nombreuses sources de stress génotoxiques qui induisent des dommages de l'ADN, les cellules ont mis en place des mécanismes complexes capables de détecter et réparer ces lésions. Parmi ces sources, figurent les rayonnements ultraviolets (UV) contenus dans la lumière solaire, qui modifient la structure de l'ADN et peuvent conduire à l'introduction de mutations. Chez l'homme, la grande majorité des dommages de l'ADN produits par les rayonnements est éliminée par le système NER (Nucleotide Excision Repair), un système capable d'exciser les nucléotides lésés et de les remplacer. Une déficience de cette voie de réparation peut mener à l'apoptose (mort programmée des cellules), et augmente la susceptibilité de développer des maladies graves telles que le cancer. Le système NER met en œuvre de nombreuses protéines impliquées dans des mécanismes variés tels que la détection, la signalisation, ou la réparation de l'ADN. La protéine eucaryote KIN17, récemment découverte dans le noyau de la cellule humaine, semble appartenir à ce système de réparation. Cependant, son rôle précis dans la réponse aux dommages de l'ADN reste à ce jour inconnu. C'est pourquoi, nous avons entrepris une caractérisation structurale et fonctionnelle de la région 51-160 de la protéine KIN17 humaine (domaine K2) afin d'améliorer la connaissance de ses fonctions, de ses partenaires biologiques, et de ses modes de fonctionnement. La première partie de ce manuscrit est consacrée à la préparation de l'échantillon de protéine en vue d'une analyse structurale par Résonance Magnétique Nucléaire (RMN). Le travail a dans un premier temps consisté à choisir et optimiser le système d'expression de domaines structuraux d'une autre protéine : la proline déshydrogénase PRODH. Dans un second temps, la meilleure stratégie de préparation de l'échantillon a été appliquée à la protéine KIN17 pour produire, puis résoudre la structure tridimensionnelle du domaine K2 par RMN et Modélisation Moléculaire. Nous avons montré que la région 51-160 de la protéine KIN17 humaine adopte un repliement caractéristique de la famille structurale « Winged Helix » des protéines de liaison aux acides nucléiques. Cependant, l'analyse des détails structuraux du domaine K2, la comparaison avec des protéines de fonction connue de la même classe structurale, et des études électrophorétiques, révèlent l'incapacité de ce domaine à lier l'ADN et l'ARN de manière autonome. En revanche, nous avons mis en évidence, par une étude RMN complémentaire, l'existence d'une surface ultra conservée impliquée dans des interactions de type protéine-protéine intra-moléculaires entre le motif « Winged Helix » de la région 51-160 et la région N-terminale 1-50 de KIN17 humaine

A costly state verification model with diversity of opinions

In simple models of borrowing and lending with ex-post asymmetric information, Gale and Hellwig (1985) and Williamson (1986) have shown that optimal debt contracts are simple debt contracts where borrowers repay a fixed interest rate whenever possible and lenders seize all the profit when borrowers default. In this note, we depart from their works by assuming that borrowers and lenders have heterogeneous beliefs, and show that simple debt contracts do not necessarily survive as optimal contracts

Optimal debt contracts and diversity of opinions: an extreme case of bunching

This paper studies optimal menus of debt contracts such as secured debentures or bonds, in the presence of diversity of opinions between borrowers and lenders. We first characterize incentive compatible contracts, then prove the existence of optimal debt contracts. Finally, we are able to explicitly characterize such optimal menus within a specific case: we notably show that borrowers optimally offer at most two contracts, which is an extreme case of bunching

Existence and monotonicity of optimal debt contracts in costly state verification models

This note gives a simple proof of the existence and monotonicity of optimal debt contracts in simple models of borrowing and lending with ex-post asymmetric information, risk-averse agents and heterogeneous beliefs. Our argument is based on the concept of nondecreasing rearrangement and on a supermodular version of Hardy-Littlewood inequality

Preliminary comparative results between FES and FDG in ER plus metastatic breast cancer: a radiomic approach

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