Housing and the macroeconomy: the role of implicit guarantees for government-sponsored enterprises

This paper studies the macroeconomic effects of implicit government guarantees of the obligations of government-sponsored enterprises. We construct a model with competitive housing and mortgage markets in which the government provides banks with insurance against aggregate shocks to mortgage default risk. We use this model to evaluate aggregate and distributional impacts of this government subsidy of owner-occupied housing. Preliminary findings indicate that the subsidy leads to higher equilibrium housing investment, higher mortgage default rates, and lower welfare. The welfare effects of this policy vary substantially across members of the population with different economic characteristics.

Housing and the Macroeconomy: The Role of Bailout Guarantees for Government Sponsored Enterprises

This paper evaluates the macroeconomic and distributional effects of government bailout guarantees for Government Sponsored Enterprises (such as Fannie Mae and Freddy Mac) in the mortgage market. In order to do so we construct a model with heterogeneous, infinitely lived households and competitive housing and mortgage markets. Households have the option to default on their mortgages, with the consequence of having their homes foreclosed. We model the bailout guarantee as a government provided and tax-financed mortgage interest rate subsidy. We find that eliminating this subsidy leads to substantially lower equilibrium mortgage origination and increases aggregate welfare, but has little effect on foreclosure rates and housing investment. The interest rate subsidy is a regressive policy: eliminating it benefits low-income and low-asset households who did not own homes or had small mortgages, while lowering the welfare of high-income, high-asset households.

Housing and the Macroeconomy: The Role of Bailout Guarantees for Government Sponsored Enterprises

This paper evaluates the macroeconomic and distributional effects of government bailout guarantees for Government Sponsored Enterprises (such as Fannie Mae and Freddy Mac) in the mortgage market. In order to do so we construct a model with heterogeneous, infinitely lived households and competitive housing and mortgage markets. Households have the option to default on their mortgages, with the consequence of having their homes foreclosed. We model the bailout guarantee as a government provided and tax-financed mortgage interest rate subsidy. We find that eliminating this subsidy leads to substantially lower equilibrium mortgage origination and increases aggregate welfare, but has little effect on foreclosure rates and housing investment. The interest rate subsidy is a regressive policy: eliminating it benefits low-income and low-asset households who did not own homes or had small mortgages, while lowering the welfare of high-income, high-asset households.Housing, Mortgage Market, Default Risk, Government-Sponsored Enterprises

Peptide-equipped tobacco mosaic virus templates for selective and controllable biomineral deposition

The coating of regular-shaped, readily available nanorod biotemplates with inorganic compounds has attracted increasing interest during recent years. The goal is an effective, bioinspired fabrication of fiber-reinforced composites and robust, miniaturized technical devices. Major challenges in the synthesis of applicable mineralized nanorods lie in selectivity and adjustability of the inorganic material deposited on the biological, rod-shaped backbones, with respect to thickness and surface profile of the resulting coating, as well as the avoidance of aggregation into extended superstructures. Nanotubular tobacco mosaic virus (TMV) templates have proved particularly suitable towards this goal: Their multivalent protein coating can be modified by high-surface-density conjugation of peptides, inducing and governing silica deposition from precursor solutions in vitro. In this study, TMV has been equipped with mineralization-directing peptides designed to yield silica coatings in a reliable and predictable manner via precipitation from tetraethoxysilane (TEOS) precursors. Three peptide groups were compared regarding their influence on silica polymerization: (i) two peptide variants with alternating basic and acidic residues, i.e. lysine–aspartic acid (KD)$_{χ}$ motifs expected to act as charge-relay systems promoting TEOS hydrolysis and silica polymerization; (ii) a tetrahistidine-exposing polypeptide (CA$_{4}$H$_{4}$) known to induce silicification due to the positive charge of its clustered imidazole side chains; and (iii) two peptides with high ZnO binding affinity. Differential effects on the mineralization of the TMV surface were demonstrated, where a (KD)$_{χ}$ charge-relay peptide (designed in this study) led to the most reproducible and selective silica deposition. A homogenous coating of the biotemplate and tight control of shell thickness were achieved

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements