The unorthodox evolution of major merger remnants into star-forming spiral galaxies

Galaxy mergers are believed to play a key role in transforming star-forming disk galaxies into quenched ellipticals. Most of our theoretical knowledge about such morphological transformations does, however, rely on idealised simulations where processes such as cooling of hot halo gas into the disk and gas accretion in the post-merger phase are not treated in a self-consistent cosmological fashion. In this paper we study the morphological evolution of the stellar components of four major mergers occurring at z=0.5 in cosmological hydrodynamical zoom-simulations. In all simulations the merger reduces the disk mass-fraction, but all galaxies simulated at our highest resolution regrow a significant disk by z=0 (with a disk fraction larger than 24%). For runs with our default physics model, which includes galactic winds from star formation and black hole feedback, none of the merger remnants are quenched, but in a set of simulations with stronger black hole feedback we find that major mergers can indeed quench galaxies. We conclude that major merger remnants commonly evolve into star-forming disk galaxies, unless sufficiently strong AGN feedback assists in the quenching of the remnant.Comment: 15 pages, 9 figures, Accepted for publication in MNRA

Zooming in on major mergers: dense, starbursting gas in cosmological simulations

We introduce the `Illustris zoom simulation project', which allows the study of selected galaxies forming in the $\Lambda$CDM cosmology with a 40 times better mass resolution than in the parent large-scale hydrodynamical Illustris simulation. We here focus on the starburst properties of the gas in four cosmological simulations of major mergers. The galaxies in our high-resolution zoom runs exhibit a bursty mode of star formation with gas consumption timescales 10 times shorter than for the normal star formation mode. The strong bursts are only present in the simulations with the highest resolution, hinting that a too low resolution is the reason why the original Illustris simulation showed a dearth of starburst galaxies. Very pronounced bursts of star formation occur in two out of four major mergers we study. The high star formation rates, the short gas consumption timescales and the morphology of these systems strongly resemble observed nuclear starbursts. This is the first time that a sample of major mergers is studied through self-consistent cosmological hydrodynamical simulations instead of using isolated galaxy models setup on a collision course. We also study the orbits of the colliding galaxies and find that the starbursting gas preferentially appears in head-on mergers with very high collision velocities. Encounters with large impact parameters do typically not lead to the formation of starbursting gas.Comment: 13 pages, 7 figures, Accepted for publication in MNRA

Payout Policy and Owners? Interests: Evidence from German Savings Banks

The savings banks? decision to distribute profits among their public owners is strongly regulated by law in order to guarantee their adequate funding via retained profits. However, the legal scope is reluctantly exhausted. In this study we examine the determinants of the savings banks? payout decision in more detail. We find that besides internal determinants also external factors regarding the savings bank?s public owner have strong explanatory power. The better the financial situation of the public owner, the less likely is the savings bank to distribute profits and to increase payouts, respectively. --Savings Banks,Germany,Payout Policy

Monopoly Pricing under Demand Uncertainty: Final Sales versus Introductory ffers

We study rationing as a tool of the monopolist’s pricing strategy when demand is uncertain. Three pricing strategies are potentially optimal in our environment: uniform pricing, final sales, and introductory offers. The final sales strategy consists in charging a high price initially, but then lowering the price while committing to a total capacity. Consumers with high valuations to pay may decide to buy at the high price since the endogenous probability of rationing is higher at the lower price. The introductory offers strategy consists in selling a limited quantity at a low price initially, and then raising price. Those consumers with high valuations who were rationed initially at the lower price may find it optimal to buy the good at the higher price. We show that while the introductory offers strategy may dominate uniform pricing, it is never optimal if the monopolist can use the final sales strategy.rationing, priority pricing, sales, demand uncertainty, introductory offer, price dispersion

Ageing and the Welfare State: Securing Sustainability

Over the next four decades, increasing old-age dependency ratios exert an enormous upward pressure on welfare spending in most developed countries. As this is mainly due to existing unfunded public pension schemes, many countries have embarked on far-reaching reforms in this area, strengthening actuarial fairness, modifying indexation rules, adding elements of prefunding and, last but not least, attempting to extend the period of economic activity. Efforts to contain costs may also be relevant with regard to public expenditure on health and long-term care but, thus far, no country has started to really deal with these issues. Still, some countries have made substantial progress in securing the long-term sustainability of their welfare systems. What remains to be considered is re-constructing the system of intergenerational transactions as a potential way of removing disincentives to raise children and invest in their human capital in the long run.demographic ageing, welfare state, public expenditure, fiscal sustainability, policy reforms

Monopoly Pricing under Demand Uncertainty: Final Sales versus Introductory Offers

We study rationing as a tool of the monopolist’s selling policy when demand is uncertain. Three selling policies are potentially optimal in our environment: uniform pricing, final sales, and introductory offers. Final sales consist in charging a high price initially, but then lowering the price while committing to a total capacity. Consumers with a high valuation may decide to buy at the high price since the endogenous probability of rationing is higher at the lower price. Introductory offers consist in selling a limited quantity at a low price initially, and then raising price. Those consumers with high valuations who were rationed initially at the lower price may find it optimal to buy the good at the higher price. We show that the optimal selling policy involves either uniform pricing or final sales. Introductory offers may dominate uniform pricing, but can never be optimal if the monopolist can also use final sales.Rationing, priority pricing, sales, demand uncertainty, introductory offer, price dispersion, advance purchase discount

How Do Banks Determine Capital? Empirical Evidence for Germany

This paper examines how capital is determined by German banks. We analyse whether the determinants found in the previous empirical literature hold for the special German banking sector with its three characteristic banking groups of savings banks, cooperative banks and other banks. On the basis of a unique data set of nearly all German banks between 1992 and 2001 provided by the Deutsche Bundesbank, we apply the generalised method of moments (GMM) within a dynamic panel data framework. The results largely confirm the findings for other countries, but show considerable differences between the three German banking groups. --Bank capital,portfolio risk,banking regulation,panel data,GMM

Intra-Generational Externalities and Inter-Generational Transfers

In an environment with asymmetric information the implementation of a first-best efficient Clarke-Groves-Vickrey (D’Aspremont-Gérard-Varet) mechanism may not be feasible if it has to be self-financing. By using intergenerational transfers, the arising budget deficit can generally be covered in every generation if the growth rate of the economy is positive. This result yields an alternative explanation for the existence of pay-as-you-go financed transfer mechanisms.pay-as-you-go, externalities, mechanism design, adverse selection

Characterization of Translocation Contact Sites Involved in the Import of Mitochondrial Proteins

Import of proteins into the mitochondrial matrix requires translocation across two membranes. Translocational intermediates of mitochondrial proteins, which span the outer and inner membrane simultaneously and thus suggest that translocation occurs in one step, have recently been described (Schleyer, M., and W. Neupert, 1985, Cell, 43:339-350). In this study we present evidence that distinct membrane areas are involved in the translocation process. Mitochondria that had lost most of their outer membrane by digitonin treatment (mitoplasts) still had the ability to import proteins. Import depended on proteinaceous structures of the residual outer membrane and on a factor that is located between the outer and inner membranes and that could be extracted with detergent plus salt. Translocational intermediates, which had been preformed before fractionation, remained with the mitoplasts under conditions where most of the outer membrane was subsequently removed. Submitochondrial vesicles were isolated in which translocational intermediates were enriched. Immunocytochemical studies also suggested that the translocational intermediates are located in areas where outer and inner membranes are in close proximity. We conclude that the membrane-potential-dependent import of precursor proteins involves translocation contact sites where the two membranes are closely apposed and are linked in a stable manner