Circle maps and C*-algebras

We consider a construction of C*-algebras from continuous piecewise monotone maps on the circle which generalizes the crossed product construction for homeomorphisms and more generally the construction of Renault, Deaconu and Anantharaman-Delaroche for local homeomorphisms. Assuming that the map is surjective and not locally injective we give necessary and sufficient conditions for the simplicity of the C*-algebra and show that it is then a Kirchberg algebra. We provide tools for the calculation of the K-theory groups and turn them into an algorithmic method for Markov maps.Comment: 37 pages, 4 figure

On compactifications of the Steinberg zero-fiber

Let G be a connected semisimple linear algebraic group over an algebraically closed field k of positive characteristic and let X denote an equivariant embedding of G. We define a distinguished Steinberg fiber N in G, called the zero-fiber, and prove that the closure of N within X is normal and Cohen-Macaulay. Furthermore, when X is smooth we prove that the closure of N is a local complete intersection.Comment: 18 page

Temporary extra jobs for immigrants: Merging lane to employment or dead-end road in welfare?

We evaluate the effects of the most frequently used German welfare-to-work program on the employment chances of immigrant welfare recipients. In particular, we investigate whether program effects differ between immigrants and natives and what might cause these potential differences. Our results reveal that the program fails to achieve its objectives. The effects are more adverse for natives, but the program does not help otherwise identical immigrants to leave the welfare system either. Therefore, the program is a dead-end road rather than a merging lane to regular employment both for natives and for immigrants. --Immigrants,employment programs,evaluation,decomposition of effects,Germany

Intensifying the Use of Benefit Sanctions – An Effective Tool to Shorten Welfare Receipt and Speed up Transitions to Employment?

Benefitt sanctions imposed on non-compliant welfare recipients are a new element in the German welfare system. In practice, the sanction policy and the application of sanctions vary considerably across the 439 welfare agencies. Based on combined administrative and survey data, these differences are used as instrumental variables to estimate the effect of sanctions on the drop-out from welfare and the transition to employment. The estimated local average treatment effect (LATE) is an estimate of the effectiveness of an intensifed use of sanctions. The results show that tightening sanction policy would be quite eective.benefit sanctions, welfare recipients, IV, LATE

Intensifying the Use of Benefit Sanctions: An Effective Tool to Shorten Welfare Receipt and Speed Up Transitions to Employment?

Benefit sanctions imposed on non-compliant welfare recipients are a new element in the German welfare system. In practice, the sanction policy and the application of sanctions vary considerably across the 439 welfare agencies. Based on combined administrative and survey data, these differences are used as instrumental variables to estimate the effect of sanctions on the drop-out from welfare and the transition to employment. The estimated local average treatment effect (LATE) is an estimate of the effectiveness of an intensified use of sanctions. The results show that tightening sanction policy would be quite effective.benefit sanctions, welfare recipients, IV, LATE

Intensifying the use of benefit sanctions: an effective tool to shorten welfare receipt and speed up transitions to employment?

Benefit sanctions imposed on non-compliant welfare recipients are a new element in the German welfare system. In practice, the sanction policy and the application of sanctions vary considerably across the 439 welfare agencies. Based on combined administrative and survey data, these differences are used as instrumental variables to estimate the effect of sanctions on the drop-out from welfare and the transition to employment. The estimated local average treatment effect (LATE) is an estimate of the effctiveness of an intensified use of sanctions. The results show that tightening sanction policy would be quite effective. --benefit sanctions,welfare recipients,IV,LATE

Short-term training programs for immigrants: do effects differ from natives and why?

We evaluate the effects of different short-term training programs on the employment chances of immigrant and native welfare recipients in Germany. In particular, we investigate whether program effects differ between both groups and what might cause these potential differences. In a first step, we evaluate program effects separately for immigrants and natives using propensity score matching estimators. To explain potential differences in effects between the groups, we suggest and apply a decomposition method based on the matching procedure that allows identification of differences due to observable characteristics and differences related to an immigrant fixed effect in a second step. --Immigrants,short-term training programs,evaluation,decomposition,matching,Germany

Magnetic edge states and magnetotransport in graphene antidot barriers

Magnetic fields are often used for characterizing transport in nanoscale materials. Recent magnetotransport experiments have demonstrated that ballistic transport is possible in graphene antidot lattices (GALs). These experiments have inspired the present theoretical study of GALs in a perpendicular magnetic field. We calculate magnetotransport through graphene antidot barriers (GABs), which are finite rows of antidots arranged periodically in a pristine graphene sheet, using a tight-binding model and the Landauer-B\"uttiker formula. We show that GABs behave as ideal Dirac mass barriers for antidots smaller than the magnetic length, and demonstrate the presence of magnetic edge states, which are localized states on the periphery of the antidots due to successive reflections on the antidot edge in the presence of a magnetic field. We show that these states are robust against variations in lattice configuration and antidot edge chirality. Moreover, we calculate the transmittance of disordered GABs and find that magnetic edge states survive a moderate degree of disorder. Due to the long phase-coherence length in graphene and the robustness of these states, we expect magnetic edge states to be observable in experiments as well

Social Dilemmas and Public Range Management: Results from the Nevada Ranch Survey

Since the late 1960s, the Nevada ranch community has come under increasing pressure from environmental groups regarding their use of public lands for livestock grazing, thus increasing tension between ranchers and public land managers and potentially reducing the social capital that facilitates action and cooperation in range management. In this paper, we use responses to a survey of all public grazing permit holders in Nevada to investigate the changing relationships between ranchers and the public land agencies, and its potential implications. In particular, we investigate factors that affect ranchers’ trust in the public land agencies, and then factors that influence the nature of the relationship between ranchers and the Bureau of Land Management and U.S. Forest Service. Low levels of trust between ranchers and public managers were most significantly related to previous disagreements and the belief in a poor future for ranching. The occurrence of wildfire on grazing land contributed most signifcantly to increased disagreement between ranchers and public agencies. Finally, as a response to conflict in the ranch community, community based initiatives, such as grass banking, are examined for their potential to bring stakeholders together to realize and address common goals. Community involvement in decision making may increase levels of social capital, reduce transaction costs, and thus allow for more effective and efficient use of the range resources.Institutions and social capital, effectiveness of range management policies

INITIAL APPLICATIONS OF FUZZY SET PROCEDURES FOR ESTIMATION OF EXPORT BASE EMPLOYMENT

Current export base methods that calculate basic and non-basic employment are too restrictive because they fail to account for uncertainty involved in the process. This paper shows the assignment of industries as either basic or non-basic by the location quotient procedure does not consistently represent the data for Nevada counties. Using fuzzy set procedures and membership functions in conjunction with the location quotient allow more flexibility in terms of matching the data for each industry in the region of interest. Using fuzzy set procedures we determine the proportion of employment that is basic and non-basic in nine non-governmental industries.Labor and Human Capital,