Planet formation from the ejecta of common envelopes

The close binary system NN Serpentis must have gone through a common envelope phase before the formation of its white dwarf. During this phase, a substantial amount of mass was lost from the envelope. The recently detected orbits of circumbinary planets are likely inconsistent with planet formation before the mass loss.We explore whether new planets may have formed from the ejecta of the common envelope and derive the expected planetary mass as a function of radius.We employed the Kashi & Soker model to estimate the amount of mass that is retained during the ejection event and inferred the properties of the resulting disk from the conservation of mass and angular momentum. The resulting planetary masses were estimated from models with and without radiative feedback. We show that the observed planetary masses can be reproduced for appropriate model parameters. Photoheating can stabilize the disks in the interior, potentially explaining the observed planetary orbits on scales of a few AU. We compare the expected mass scale of planets for 11 additional systems with observational results and find hints of two populations, one consistent with planet formation from the ejecta of common envelopes and the other a separate population that may have formed earlier. The formation of the observed planets from the ejecta of common envelopes seems feasible. The model proposed here can be tested through refined observations of additional post-common envelope systems. While it appears observationally challenging to distinguish between the accretion on pre-existing planets and their growth from new fragments, it may be possible to further constrain the properties of the protoplanetary disk through additional observations of current planetary candidates and post-common envelope binary systems.Comment: 12 pages, 8 figures, 3 tables. Accepted at A&

Forecast quality and simple instrument rules: a real-time data approach

We start from the assertion that a useful monetary policy design should be founded on more realistic assumptions about what policymakers can know at the time when policy decisions have to be made. Since the Taylor rule – if used as an operational device - implies a forward looking behaviour, we analyze the reliability of the input information. We investigate the forecasting performance of OECD projections for GDP growth rates and inflation. We diagnose a much better forecasting record for inflation rates compared to GDP growth rates, which for most countries are almost uninformative at the time a Taylor rule should sensibly be applied. Using this data set, we find significant differences between Taylor rules estimated over revised data compared to real-time data. There is evidence that monetary policy seems to react more actively in real time than rules estimated over revised data suggest. Given the evidence of systematic errors in OECD forecasts, in a next step we attempt to correct for these forecast biases and check to which extent this can lower the errors in interest rate policy setting. An ex-ante simulation for the years 1991 to 2001 supports the proposal that correcting for forecast errors and biases based on an error model can lower the resulting policy error in interest rate setting for most countries under consideration. In addition we investigate to what extent structural changes in the policy reaction behaviour can be handled with moving instead of expanding samples. Our results point out that the information set available needs a careful examination when applied to instrument rules like those of the Taylor type. Limited forecast quality and significant data revisions recommend a more sophisticated handling of the dated information, for which we present an operational procedure that has the potential of reducing the risk of severe policy errors. --Monetary policy rules,economic forecasting,OECD,real-time data

Siegel Disks and Periodic Rays of Entire Functions

Let f be an entire function whose set of singular values is bounded and suppose that f has a Siegel disk such that f restricts to a homeomorphism of the boundary. We show that the Siegel disk is bounded. Using a result of Herman, we deduce that if additionally the rotation number of the Siegel disk is Diophantine, then its boundary contains a critical point of f. Suppose furthermore that all singular values of f lie in the Julia set. We prove that, if f has a Siegel disk $U$ whose boundary contains no singular values, then the condition that f is a homeomorphism of the boundary of U is automatically satisfied. We also investigate landing properties of periodic dynamic rays by similar methods.Comment: 22 pages, 4 figures. A problem with the image quality of some of the figures was fixed. Some minor corrections were also made. Final versio

Stringency and Distribution in the EU Emissions Trading Scheme –The 2005 Evidence

With the release of the verified emissions for installations covered by the EU Emissions Trading Scheme for the first trading year 2005 we are able to compare actual emissions and allowances for each installation. Based on data available for 24 Member States as of January 2007, this paper uses a thorough data analysis for about 9,900 installations to investigate evidence on three issues: first, the stringency of the total allocation cap and allocation differences both among the Member States and a selection of emission intensive sectors; second, the distribution of the size of installations; and third, the spread of allocation discrepancies and possible allocation biases regarding the size of installations.Emission Trading, EU Emissions Trading Scheme, Climate Policy

Außenhandel und Umwelt: Was bringt Cancún?

Im Rahmen der Klimarahmenkonvention der UNO treffen die Vertragsstaaten zu ihren Verhandlungen (Conference of Parties, COP 16) von 29. November bis 10. Dezember 2010 in Cancun, Mexiko zusam-men. Die naturwissenschaftlichen Grundlagen für die Szenarien des Klimawandels haben sich über die letzten Jahre weiter erhärtet und weisen auf die Notwendigkeit einer umfassenden Reduktion der Treibhausgasemissionen hin – einer Reduktion um ein Vielfaches der im Kyoto-Vertrag vereinbarten Ziele und unter Einbeziehung von wesentlich mehr als der damaligen Vertragsstaaten. Die Vorgänger-Vertragsstaaten-Konferenz in Kopenhagen 2009 markierte eine fundamentale Änderung in der inter-nationalen Klimapolitik-Architektur, statt völkerrechtlich verbindlichen gemeinsamen Zielen dürfte es nun den einzelnen Staaten überlassen bleiben welche Handlungen sie setzen. Einzelstaatliche Klimapolitik läuft ohne gemeinsame Ziele aber Gefahr mit wesentlichen Wettbewerbseffekten im internatio-nalen Handel verbunden zu sein. Für einige Wirtschaftssektoren zeichnen sich technologische Quan-tensprünge für „Low Carbon“ Strukturen ab. Für andere Sektoren werden globale sektorale Treibhaus-gas-Abkommen diskutiert. Vorschläge liegen insbesondere aber auch für Border Tax Adjustments vor, um potenziell nachteiligen Wettbewerbseffekten vorzubeugen. Die Interessenlage der Verhandlungs-staaten ist dabei durchaus komplex.

Testing for the economic and environmental impacts of EU Emissions Trading System: A panel GMM approach

The COVID‑19 pandemic has had a great impact on the economies of the EU, also with regard to the future of EU climate policy. The plan to rebuild and support the EU economy seems to place less emphasis on environmental issues as the main focus has been shifted to a quick economic recovery. One of the issues discussed in this context is the continued operation of the EU ETS. From this perspective, empirical research devoted to a thorough analysis of the impact of the EU ETS is of particular importance. At the same time, the current economic literature lacks any econometric analyzes devoted to the issues in question that would use detailed and reliable databases on EU ETS like the one provided by the Wegener Center for Climate and Global Change. The aim of this paper is to make a preliminary assessment of the effectiveness of the EU ETS in terms of reducing the actual emissions while preserving the economic growth of EU member states. The extensive empirical analysis is focused on examining the issues in question for different phases of the EU ETS and various groups of EU economies that vary in terms of economic development and the overall air pollutant emission

The Demand for Health Insurance in a Poor Economy: Evidence from Burkina Faso

We investigate the properties of health insurance demand in Burkina Faso, where we offered poor households a voluntary health insurance product at half the usual price. The targeting procedure we implemented delivers a fuzzy regression discontinuity design, which identifies the price elasticity of demand for health insurance as well as associated selection effects. We find large price elasticities among urban households, whereas the demand of rural households is price-inelastic. There are important selection effects, with widowed male household heads being most price-sensitive. Correlating these heterogeneous effects with survey data on informal transfers and health expenditures, our results suggest that informal risk-sharing largely crowds out formal insurance and that a single insurance product may fail to align with poor households' small health budgets. We find no adverse selection into health insurance

The pseudokinase MLKL mediates programmed hepatocellular necrosis independently of RIPK3 during hepatitis

Although necrosis and necroinflammation are central features of many liver diseases, the role of programmed necrosis in the context of inflammation-dependent hepatocellular death remains to be fully determined. Here, we have demonstrated that the pseudokinase mixed lineage kinase domain-like protein (MLKL), which plays a key role in the execution of receptor interacting protein (RIP) lcinase-dependent necroptosis, is upregulated and activated in human autoimmune hepatitis and in a murine model of inflammation-dependent hepatitis. Using genetic and pharmacologic approaches, we determined that hepatocellular necrosis in experimental hepatitis is driven by an MLKL-dependent pathway that occurs independently of RIPK3. Moreover, we have provided evidence that the cytotoxic activity of the proinflammatory cytokine IFN-gamma in hepatic inflammation is strongly connected to induction of MLKL expression via activation of the transcription factor STAT1. In summary, our results reveal a pathway for MLKL-dependent programmed necrosis that is executed in the absence of RIPK3 and potentially drives the pathogenesis of severe liver diseases

Testing for economic and environmental impacts of EU Emissions Trading System: A panel GMM approach

The COVID 19 pandemic has had a great impact on the European Union economies in many aspects, also with regard to the discussion on the future of EU climate policy. The plan to rebuild and support the European Union's economy, which is currently under discussion at European governments summits, seems to place less emphasis on environmental issues as the main focus is being placed on a quick recovery of EU economy in the realms of global competition. One of the issues discussed in the EU's recovery plan following the COVID19 epidemic is the continued operation of the EU ETS. In this context, empirical research devoted to a thorough analysis of the impact of the EU emissions trading program is of particular importance. At the same time, current economic literature lacks any econometric analyzes devoted to the issues in question that would use detailed and reliable databases on EU ETS like the one provided by the Wegener Center for Climate and Global Change. The aim of this paper is to make a preliminary assessment of the effectiveness of the EU ETS in terms of reducing the actual emissions to the air while preserving economic growth of EU member states. The extensive empirical analysis is focused on examining the issues in question for different phases of the EU ETS and various groups of EU economies that vary in terms of economic development and the overall air pollutant emission