Payroll Taxes, Social Insurance and Business Cycles

Payroll taxes represent a major distortionary in uence of governments on labor markets. This paper examines the role of payroll taxation and the social safety net for cyclical uctuations in a nonmonetary economy with labor market frictions and unemployment insurance, when the latter is only imperfectly related to search effort. A balanced social insurance budget renders gross wages more rigid over the cycle and, as a result, strengthens the modelÂ’s endogenous propagation mechanism. For conventional calibrations, the model generates a negatively sloped Beveridge curve as well as substantial volatility and persistence of vacancies and unemployment.business cycles, labor markets, payroll taxes, unemployment, consumption-tightness puzzle

Payroll Taxes, Social Insurance and Business Cycles

Payroll taxes represent a major distortionary influence of governments on labor markets. This paper examines the role of payroll taxation and the social safety net for cyclical fluctuations in a nonmonetary economy with labor market frictions and unemployment insurance, when the latter is only imperfectly related to search effort. A balanced social insurance budget renders gross wages more rigid over the cycle and, as a result, strengthens the model’s endogenous propagation mechanism. For conventional calibrations, the model generates a negatively sloped Beveridge curve as well as substantial volatility and persistence of vacancies and unemployment. herunterladen.Business cycles, labor markets, payroll taxes, unemployment, consumptiontightness puzzle

Payroll Taxes, Social Insurance and Business Cycles

Payroll taxes represent a major distortionary influence of governments on labor markets. This paper examines the role of payroll taxation and the social safety net for cyclical fluctuations in a nonmonetary economy with labor market frictions and unemployment insurance, when the latter is only imperfectly related to search effort. A balanced social insurance budget renders gross wages more rigid over the cycle and, as a result, strengthens the model's endogenous propagation mechanism. For conventional calibrations, the model generates a negatively sloped Beveridge curve as well as substantial volatility and persistence of vacancies and unemployment.business cycles, labor markets, payroll taxes, unemployment, consumption-tightness puzzle

Revisiting Sovereign Bankruptcy

Sovereign debt crises occur regularly and often violently. Yet there is no legally and politically recognized procedure for restructuring the debt of bankrupt sovereigns. Procedures of this type have been periodically debated, but so far been rejected, for two main reasons. First, countries have been reluctant to give up power to supranational rules or institutions, and creditors and debtors have felt that there were sufficient instruments for addressing debt crises at hoc. Second, fears that making debt easier to restructure would raise the costs and reduce the amounts of sovereign borrowing in many countries. This was perceived to be against the interests of both the providers of both creditors and major borrowers. This report argues that both the nature and our understanding of sovereign debt problems have changed, over the course of the last decade, in a direction that creates a much stronger case for an orderly sovereign bankruptcy regime today than ten years ago. Pre-crisis policy mistakes are now recognized to be a much more severe problem for borrowing countries than the costs or limited availability of private financing. Recent court rulings – particularly a recent U.S. ruling that gives holdout creditors that decline a restructuring offer the right to interfere with payments to the creditors that accept such an offer. This will complicate efforts to resolve future debt crises on an ad hoc basis. Finally, sovereign debt crises are no longer just a problem in emerging markets, but a core concern in advanced countries as well – particularly in the Euro area. If the Euro is to survive, this will require both better ways to resolve debt crises and stronger, market-based incentives that prevent debt problems from occurring in the first place. To address these problems, policy proposals are presented at two levels: for the Euro area, and globally. A Euro area sovereign debt restructuring regime could be developed by amending the Treaty establishing the European Stability Mechanism (ESM). This would both restrict the scope for lending to highly indebted countries without also restructuring their debts, and protect Euro area members receiving ESM financial assistance from legal action by holdout creditors. At the global level, a number of proposals are discussed, ranging from a coordinated introduction of aggregate collective action clauses that would allow a supermajority of bondholders across all bonds to amend bond payment terms to an amendment of the IMF articles that would limit the legal remedies of holdouts when a debt restructuring proposal has been accepted both by a majority of creditors and endorsed by the IMF

A rigorous analysis of high order electromagnetic invisibility cloaks

There is currently a great deal of interest in the invisibility cloaks recently proposed by Pendry et al. that are based in the transformation approach. They obtained their results using first order transformations. In recent papers Hendi et al. and Cai et al. considered invisibility cloaks with high order transformations. In this paper we study high order electromagnetic invisibility cloaks in transformation media obtained by high order transformations from general anisotropic media. We consider the case where there is a finite number of spherical cloaks located in different points in space. We prove that for any incident plane wave, at any frequency, the scattered wave is identically zero. We also consider the scattering of finite energy wave packets. We prove that the scattering matrix is the identity, i.e., that for any incoming wave packet the outgoing wave packet is the same as the incoming one. This proves that the invisibility cloaks can not be detected in any scattering experiment with electromagnetic waves in high order transformation media, and in particular in the first order transformation media of Pendry et al. We also prove that the high order invisibility cloaks, as well as the first order ones, cloak passive and active devices. The cloaked objects completely decouple from the exterior. Actually, the cloaking outside is independent of what is inside the cloaked objects. The electromagnetic waves inside the cloaked objects can not leave the concealed regions and viceversa, the electromagnetic waves outside the cloaked objects can not go inside the concealed regions. As we prove our results for media that are obtained by transformation from general anisotropic materials, we prove that it is possible to cloak objects inside general crystals.Comment: The final version is now published in Journal of Physics A: Mathematical and Theoretical, vol 41 (2008) 065207 (21 pp). Included in IOP-Selec

A mechano- and thermoresponsive luminescent cyclophane

The first fluorescent cyclophane with mechano- and thermoresponsive solid-state fluorescence characteristics is reported. The new cyclophane comprises two 9,10-bis(phenylethynyl)anthracene moieties that are bridged by tetraethylene glycol spacers. The stimuli-responsiveness is based on molecular assembly changes

Mechanochemistry in polymers with supramolecular mechanophores

Mechanochemistry is a burgeoning field of materials science. Inspired by nature, many scientists have looked at different ways to introduce weak bonds into polymeric materials to impart them with function and in particular mechano-responsiveness. In the following sections, the incorporation of some of the weakest bonds, i.e. non- covalent bonds, into polymeric solids is being surveyed. This review covers sequentially π–π interactions, H-bonding and metal-ligand coordination bonds and tries to highlight some of the advantages and limitations of such systems, while providing some key perspective of what may come next in this tantalizing field