The Ricci flow on a cylinder

In this paper we study the Ricci flow on surfaces homeomorphic to a cylinder (that is, a product of the circle with a compact interval). We prove longtime existence results, results on the asymptotic behavior of the flow, and we report on an interesting phenomenon: convergence to constant curvature in the normalised flow,under certain assumptions on the initial data, cannot be exponential.Comment: Comments and criticism more than welcom

Phase diagram of orbital-selective Mott transitions at finite temperatures

Mott transitions in the two-orbital Hubbard model with different bandwidths are investigated at finite temperatures. By means of the self-energy functional approach, we discuss the stability of the intermediate phase with one orbital localized and the other itinerant, which is caused by the orbital-selective Mott transition (OSMT). It is shown that the OSMT realizes two different coexistence regions at finite temperatures in accordance with the recent results of Liebsch. We further find that the particularly interesting behavior emerges around the special condition $U=U'$ and J=0, which includes a new type of the coexistence region with three distinct states. By systematically changing the Hund coupling, we establish the global phase diagram to elucidate the key role played by the Hund coupling on the Mott transitions.Comment: 4 pages, 6 figure

Distribution, diversity and evolution of endogenous retroviruses in perissodactyl genomes

The evolution of mammalian genomes has been shaped by interactions with endogenous retroviruses (ERVs). In this study, we investigated the distribution and diversity of ERVs in the mammalian order Perissodactyla, with a view to understanding their impact on the evolution of modern equids (family Equidae). We characterize the major ERV lineages in the horse genome in terms of their genomic distribution, ancestral genome organization and time of activity. Our results show that subsequent to their ancestral divergence from rhinos and tapirs, equids acquired four novel ERV lineages. We show that two of these proliferated extensively in the lineage leading to modern horses, and one contains loci that are actively transcribed in specific tissues. In addition, we show that the white rhinoceros has resisted germline colonisation by retroviruses for over 54 million years - longer than any other extant mammalian species. The map of equine ERVs that we provide here will be of great utility to future studies aiming to investigate the potential functional roles of equine ERVs, and their impact on equine evolution

The Dynamic (In)efficiency of Monetary Policy by Committee

This paper develops a model where the value of the monetary policy instrument is selected by a heterogenous committee engaged in a dynamic voting game. Committee members differ in their institutional power and, in certain states of nature, they also differ in their preferred instrument value. Preference heterogeneity and concern for the future interact to generate decisions that are dynamically inefficient and inertial around the previously-agreed instrument value. This model endogenously generates autocorrelation in the policy variable and provides an explanation for the empirical observation that the nominal interest rate under the central bank's control is infrequently adjustedCommittees, status-quo bias, interest-rate smoothing, dynamic voting

The Dynamic (In)efficiency of Monetary Policy by Committee.

This paper develops a model where the value of the monetary policy instrument is selected by a heterogenous committee engaged in a dynamic voting game. Committee members differ in their institutional power, and in certain states of nature, they also differ in their preferred instrument value. Preference heterogeneity and concern for the future interact to generate decisions that are dynamically inefficient and inertial around the previously agreed instrument value. This model endogenously generates autocorrelation in the policy variable and helps explain the empirical observation that the distribution of actual interest rate changes has a mode of zero.Interest rate smoothing; status-quo bias; policy conservatism; policy inertia; gridlock interval; dynamic voting;

Dissent in Monetary Policy Decisions

Voting records indicate that dissents in monetary policy committees are frequent and predictability regressions show that they help forecast future policy decisions. In order to study whether the latter relation is causal, we construct a model of committee decision making and dissent where members' decisions are not a function of past dissents. The model is estimated using voting data from the Bank of England and the Riksbank. Stochastic simulations show that the decision-making frictions in our model help account for the predictive power of current dissents. The eect of institutional characteristics and structural parameters on dissent rates is examined using simulations as well.Committees, voting models, political economy of central banking

Nonlinear Monetary Policy Rules: Some New Evidence for the U.S.

This paper derives optimal monetary policy rules in setups where certainty equivalence does not hold because either central bank preferences are not quadratic, and/or the aggregate supply relation is nonlinear. Analytical results show that these features lead to sign and size asymmetries, and nonlinearities in the policy rule. Reduced-form estimates indicate that US monetary policy can be characterized by a nonlinear policy rule after 1983, but not before 1979. This finding is consistent with the view that the Fed's inflation preferences during the Volcker-Greenspan regime differ considerably from the ones during the Burns-Miller regime.Publicad