Furlough and household financial distress during the COVID-19 pandemic

We study how being furloughed affects household financial distress during the COVID-19 pandemic in the United Kingdom. Furlough increases the probability of late housing and bill payments by 30% and 19%, respectively. At the aggregate level, furlough increases the incidence of financial distress by 3.38 percentage points. To offset furlough-induced income reductions, individuals significantly reduce consumption and spend savings. Relative to unemployment, the potential alternative in the absence of a furlough scheme, furlough reduces the incidence of financial distress by 95%. Estimates show an 80% government contribution to furloughed workers' wages minimizes the incidence of financial distress at the lowest cost to taxpayers

Mechanical Stability and Fibrinolytic Resistance of Clots Containing Fibrin, DNA, and Histones

Neutrophil extracellular traps are networks of DNA and associated proteins produced by nucleosome release from activated neutrophils in response to infection stimuli and have recently been identified as key mediators between innate immunity, inflammation, and hemostasis. The interaction of DNA and histones with a number of hemostatic factors has been shown to promote clotting and is associated with increased thrombosis, but little is known about the effects of DNA and histones on the regulation of fibrin stability and fibrinolysis. Here we demonstrate that the addition of histone-DNA complexes to fibrin results in thicker fibers (increase in median diameter from 84 to 123 nm according to scanning electron microscopy data) accompanied by improved stability and rigidity (the critical shear stress causing loss of fibrin viscosity increases from 150 to 376 Pa whereas the storage modulus of the gel increases from 62 to 82 pascals according to oscillation rheometric data). The effects of DNA and histones alone are subtle and suggest that histones affect clot structure whereas DNA changes the way clots are lysed. The combination of histones + DNA significantly prolongs clot lysis. Isothermal titration and confocal microscopy studies suggest that histones and DNA bind large fibrin degradation products with 191 and 136 nm dissociation constants, respectively, interactions that inhibit clot lysis. Heparin, which is known to interfere with the formation of neutrophil extracellular traps, appears to prolong lysis time at a concentration favoring ternary histone-DNA-heparin complex formation, and DNase effectively promotes clot lysis in combination with tissue plasminogen activator

Asymmetries in risk premia, macroeconomic uncertainty and business cycles

A large literature suggests that the expected equity risk premium is countercyclical. Using a variety of different measures for this risk premium, we document that it also exhibits growth asymmetry, i.e. the risk premium rises sharply in recessions and declines much more gradually during the following recoveries. We show that a model with recursive preferences, in which agents cannot perfectly observe the state of current productivity, can generate the observed asymmetry in the risk premium. Key for this result are endogenous fluctuations in uncertainty which induce procyclical variations in agent’s nowcast accuracy. In addition to matching moments of the risk premium, the model is also successful in generating the growth asymmetry in macroeconomic aggregates observed in the data, and in matching the cyclical relation between quantities and the risk premium

Nanostruture of fibrin fibers.

La formation d'un caillot de fibrine, processus clé de la coagulation sanguine, implique la polymérisation des monomères de fibrinogène en un réseau de fibres de fibrine. Bien que ce réseau contrôle l'ensemble des propriétés mécaniques du caillot et constitue le squelette sur lequel se base la reconstruction des tissus, sa structure aux échelles inférieures au micron est très mal caractérisée. Nous avons démontré que l'analyse du spectre de lumière visible transmis à travers un caillot permet de déterminer simultanément, quantitativement et en conditions quasi-physiologiques, plusieurs paramètres essentiels de cette nanostructure, à savoir le rayon et la concentration interne en protéines des fibres. Cette méthode de spectrophotométrie a montré le caractère extraordinairement poreux de ces fibres et comment l'environnement de la réaction (concentrations en fibrinogène, en thrombine, température, force ionique) influe sur leur dimension et leur porosité. Cette méthode a ensuite permis de caractériser les effets respectifs sur cette structure de différentes molécules anti-coagulantes, montrant l'action spécifique de l'enoxaparine par rapport aux héparines non-fractionnées et au pentasaccharide. Enfin, nous avons construit un prototype à vocation hospitalière (spectrophotomètre) afin d'étudier la cinétique de polymérisation de la fibrine, non seulement en système purifié en combinaison avec nos spectres de diffusion de rayons X, mais également sur des plasmas de patients présentant des troubles de l'hémostase. Des discussions sont en cours avec un laboratoire pharmaceutique afin d'intégrer cette méthode sur des appareils de diagnostic.The formation of a fibrin clot is one of the major processes leading to blood coagulation. It involves the polymerization of fibrinogen monomers into a network of fibrin fibers. This network controls the overall mechanical properties of the clot and serves as a scaffold to promote wound healing. However its structure at scales less than one micron is very poorly characterized. We demonstrated that an analysis of the visible light spectra transmitted through fibrin clots enables the simultaneous determination, in quantitative terms and in conditions near physiological, of several key parameters of this nanostructure, i.e. the radius and the protein content of the fibers. This spectrophotometry technique has shown the extraordinary porous nature of these fibers and how the reaction parameters (fibrinogen and thrombin concentrations, temperature, ionic strength) control their size and their porosity. This method was then used to characterize the respective effects on the structure of different anticoagulant molecules, showing the specific action of enoxaparin compared with unfractionated heparin and pentasaccharide. We built a prototype (spectrophotometer), used at hospital, to study the kinetics of fibrin polymerization, not only in purified system in combination with our X-ray spectra, but also in plasmas of patients with bleeding disorders. Discussions are underway with a pharmaceutical company to integrate this method on diagnostic equipment

Suivi spectroscopique d'un caillot sanguin

Z2008.0001 Projet de fin d'études troisième année. Février-Juin 200

Essays on macroeconomic dynamics: learning, uncertainty, and heterogeneity in credit crises

This thesis covers two research topics. Chapter 2 is an investigation into the properties of the equity risk premium and its relationships with uncertainty and macroeconomic fluctuations. A large literature suggests that the expected equity risk premium is countercyclical. Using a variety of different measures for this risk premium, we document that it also exhibits growth asymmetry, i.e. the risk premium rises sharply in recessions and declines much more gradually during the following recoveries. We show that a model with recursive preferences, in which agents cannot perfectly observe the state of current productivity, can generate the observed asymmetry in the risk premium. Key for this result are endogenous fluctuations in uncertainty which induce procyclical variations in agent's nowcast accuracy. In addition to matching moments of the risk premium, the model is also successful in generating the growth asymmetry in macroeconomic aggregates observed in the data, and in matching the cyclical relation between quantities and the risk premium. Chapters 3 and 4 are an investigation into the distribution and dynamics of household debt. We present new empirical facts on the distributional dynamics of household debt around the Great Recession in the US using survey data from the Panel Study of Income Dynamics. We document that it is the 60% of households toward the middle of the income distribution that are responsible for the aggregate reduction of debt from the onset of the financial crisis in 2007 until 2015, not the 40% in the tails of the distribution. We extend the current class of heterogeneous-household models by explicitly tracking the distributions of gross debt and gross savings separately during a simulated credit crunch - instead of calculating exclusively the net financial positions of households as in the standard framework. The model successfully replicates the relative importance of the different income groups in the aggregate reduction of household debt. The results are driven by endogenous heterogeneity in the intertemporal utility cost of debt. In addition, the models provides new insights into the effectiveness of monetary policy when households are highly indebted. We show that collateralised debt is a stronger channel than liquid savings for the transmission of monetary policy

Nanostructure des fibres de fibrine

The formation of a fibrin clot is one of the major processes leading to blood coagulation. It involves the polymerization of fibrinogen monomers into a network of fibrin fibers. This network controls the overall mechanical properties of the clot and serves as a scaffold to promote wound healing. However its structure at scales less than one micron is very poorly characterized. We demonstrated that an analysis of the visible light spectra transmitted through fibrin clots enables the simultaneous determination, in quantitative terms and in conditions near physiological, of several key parameters of this nanostructure, i.e. the radius and the protein content of the fibers. This spectrophotometry technique has shown the extraordinary porous nature of these fibers and how the reaction parameters (fibrinogen and thrombin concentrations, temperature, ionic strength) control their size and their porosity. This method was then used to characterize the respective effects on the structure of different anticoagulant molecules, showing the specific action of enoxaparin compared with unfractionated heparin and pentasaccharide. We built a prototype (spectrophotometer), used at hospital, to study the kinetics of fibrin polymerization, not only in purified system in combination with our X-ray spectra, but also in plasmas of patients with bleeding disorders. Discussions are underway with a pharmaceutical company to integrate this method on diagnostic equipment.La formation d'un caillot de fibrine, processus clé de la coagulation sanguine, implique la polymérisation des monomères de fibrinogène en un réseau de fibres de fibrine. Bien que ce réseau contrôle l'ensemble des propriétés mécaniques du caillot et constitue le squelette sur lequel se base la reconstruction des tissus, sa structure aux échelles inférieures au micron est très mal caractérisée. Nous avons démontré que l'analyse du spectre de lumière visible transmis à travers un caillot permet de déterminer simultanément, quantitativement et en conditions quasi-physiologiques, plusieurs paramètres essentiels de cette nanostructure, à savoir le rayon et la concentration interne en protéines des fibres. Cette méthode de spectrophotométrie a montré le caractère extraordinairement poreux de ces fibres et comment l'environnement de la réaction (concentrations en fibrinogène, en thrombine, température, force ionique) influe sur leur dimension et leur porosité. Cette méthode a ensuite permis de caractériser les effets respectifs sur cette structure de différentes molécules anti-coagulantes, montrant l'action spécifique de l'enoxaparine par rapport aux héparines non-fractionnées et au pentasaccharide. Enfin, nous avons construit un prototype à vocation hospitalière (spectrophotomètre) afin d'étudier la cinétique de polymérisation de la fibrine, non seulement en système purifié en combinaison avec nos spectres de diffusion de rayons X, mais également sur des plasmas de patients présentant des troubles de l'hémostase. Des discussions sont en cours avec un laboratoire pharmaceutique afin d'intégrer cette méthode sur des appareils de diagnostic

Asymmetries in risk premia, macroeconomic uncertainty and business cycles

A large literature suggests that the expected equity risk premium is countercyclical. Using a variety of different measures for this risk premium, we document that it also exhibits growth asymmetry, i.e. the risk premium rises sharply in recessions and declines much more gradually during the following recoveries. We show that a model with recursive preferences, in which agents cannot perfectly observe the state of current productivity, can generate the observed asymmetry in the risk premium. Key for this result are endogenous fluctuations in uncertainty which induce procyclical variations in agent’s nowcast accuracy. In addition to matching moments of the risk premium, the model is also successful in generating the growth asymmetry in macroeconomic aggregates observed in the data, and in matching the cyclical relation between quantities and the risk premium