Quantum Pair Creation of Soliton Domain Walls

A large body of experimental evidence suggests that the decay of the false vacuum, accompanied by quantum pair creation of soliton domain walls, can occur in a variety of condensed matter systems. Examples include nucleation of charge soliton pairs in density waves [eg. J. H. Miller, Jr. et al., Phys. Rev. Lett. 84, 1555 (2000)] and flux soliton pairs in long Josephon junctions. Recently, Dias and Lemos [J. Math. Phys. 42, 3292 (2001)] have argued that the mass $m$ of the soliton should be interpreted as a line density and a surface density, respectively, for (2+1)-D and (3+1)-D systems in the expression for the pair production rate. As the transverse dimensions are increased and the total mass (energy) becomes large, thermal activation becomes suppressed, so quantum processes can dominate even at relatively high temperatures. This paper will discuss both experimental evidence and theoretical arguments for the existence of high-temperature collective quantum phenomena

Dominant Folding Pathways of a WW Domain

We investigate the folding mechanism of the WW domain Fip35 using a realistic atomistic force field by applying the Dominant Reaction Pathways (DRP) approach. We find evidence for the existence of two folding pathways, which differ by the order of formation of the two hairpins. This result is consistent with the analysis of the experimental data on the folding kinetics of WW domains and with the results obtained from large-scale molecular dynamics (MD) simulations of this system. Free-energy calculations performed in two coarse-grained models support the robustness of our results and suggest that the qualitative structure of the dominant paths are mostly shaped by the native interactions. Computing a folding trajectory in atomistic detail only required about one hour on 48 CPU's. The gain in computational efficiency opens the door to a systematic investigation of the folding pathways of a large number of globular proteins

The Presidency and the Executive Branch in Latin America: What We Know and What We Need to Know

The presidential politics literature depicts presidents either as all- powerful actors or figureheads and seeks to explain outcomes accordingly. Th e president and the executive branch are nonetheless usually treated as black boxes, particularly i n developing countries, even though the presidency has evolved into an extremely complex branch of government. While these developments have been studied in the U nited States, far less i s known in other countries, particularly in Latin America, where presi dential systems have been considered the source of all goods and evils. To help close the knowledge gap and explore differences in policymaking characteristics not only between Latin America and the US but also across Latin American countries, this paper s ummarizes the vast literature on the organization and resources of the Executive Branch in the Americas and sets a research agenda for the study of Latin American presidencies.Fil: Bonvecchi, Alejandro. Universidad Torcuato Di Tella. Departamento de Ciencia Política y Estudios Internacionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scartascini, Juan Carlos. Banco Interamericano de Desarrollo; Estados Unido

Industrial Policies in Colombia

This paper surveys and analyzes industrial policies in Colombia, finding extensive use of productive development policies (PDPs) and despite claims of only moderate government intervention. Rarely explicitly associated with the need to address market failures, PDPs are instead associated with economic reactivation and vaguely defined competitiveness. There are also PDPs that address government failures considered unlikely to be corrected by first-best interventions. Colombia has made progress, however, in structuring an institutional setting for PDP design that is sufficiently linked with private sector groups to elicit information on constraints and opportunities that require government intervention. Nonetheless, the overall set of PDPs in place still lacks coherence and is not always guided by the policy requests of the private sector more widely defined

Gender Differences in Competitiveness and Risk Taking: Comparing Children in Colombia and Sweden

We explore gender differences in preferences for competition and risk among children aged 9-12 in Colombia and Sweden, two countries differing in gender equality according to macro indices. We include four types of tasks that vary in gender stereotyping when looking at competitiveness: running, skipping rope, math and word search. We find that boys and girls are equally competitive in all tasks and all measures in Colombia. Unlike the consistent results in Colombia, the results in Sweden are mixed, with some indication of girls being more competitive than boys in some tasks in terms of performance change, whereas boys are more likely to choose to compete in general. Boys in both countries are more risk taking than girls, with a smaller gender gap in Sweden

Is Social Assistance Contributing to Higher Informality in Turkey?

Although still low for European standards, investments in Social Assistance (SA) transfers in Turkey have been increasing in recent years. The government is expanding access to subsidized health for individuals in the informal sector through a rapid expansion of the Green Card program. Generous non-contributory programs, such as the Green Card, may create perverse incentives for individuals to join or remain in the informal sector as they can access free services without paying taxes and/or contributions, thus potentially being able to get higher “net” labor earnings than in the formal sector. Despite the fact that the Green Card is a large and generous program offered to individuals in the informal sector, empirical analysis in this report does not find an actual impact of the program (or of its rapid expansion) on informality. The reason behind this finding is the existence of a very large differential in wages between formal and informal workers explained by differences worker’s productivity. Low-wage workers facing the possibility to move from the informal sector to the formal sector would have strong incentives to do so even if this would imply losing all SA benefits. As such, the expected monetary and job security gains of having a formal job dominate those of having an informal job even after accounting for SA transfers

Worker or Shirker - Who Evades More Taxes? A Real Effort Experiment

With the help of a real effort experiment, we analyze if tax evasion depends on the amount of effort invested to generate income. In three treatments, subjects were either endowed with income or had to work moderately or hard to earn it. In line with prospect theory, subjects evaded more taxes when they worked hard for their income. We find little evidence for the prediction that tax evasion in the endowed treatment is higher than in the moderate work treatment