"This is Ghanaian territory!" Land conflicts in transnational localities on the Burkina Faso-Ghana border

Traditional land rights in Dagara and Sisala societies in Burkina Faso and Ghana which were stateless in pre-colonial times are closely connected with the concept of earth-shrine parishes under the protection of a local land god and ideally under the control of the “first-comers” to the area. The earth priests perform regular sacrifices at the shrine and allocate land to later immigrants as well as the right to build houses and to bury their dead, often in exchange for gifts. The international border between Ghana and Burkina Faso, which was drawn up in 1898 and runs along the 11th parallel, often cuts across earth-shrine parishes. Particularly since the border demarcation exercise in the 1970s, the spatial separation of the Sisala earth priests on one side of the border from the Dagara immigrants on the other side has given rise to intricate conflicts over land rights. The paper will present the history of one such conflict and look at the various landrelated discourses – traditionalist, nationalist, and Christian – which the adversaries put forward in order to substantiate their claims

Settlement histories and ethnic frontiers

One of the powerful conventional images of pre-colonial Africa is that of a continent of more or less immobile ethnic groups, living since time immemorial on their ancestral lands, steeped in their traditional cultures. In this image, Africa appears like a mosaic, with clearcut ethnic boundaries, each sherd representing a different people cum language cum culture cum territory. Since a number of years, however, historians and anthropologists of Africa have insisted that this image is misleading. Most pre-colonial societies were characterised by mobility, overlapping networks, multiple group membership and the contextdependent drawing of boundaries. Communities could be based on neighbourhood, kinship and common loyalties to a king, but this did not absolutely have to include notions of a common origin, a common language or a common culture. Our own research on the West African savannah has also shown the enormous importance of mobility. Among the societies of southern and southwestern Burkina Faso, for instance, which several projects have studied, there is hardly a single village whose history has not been characterised repeatedly by the arrival and settlement of new groups and the departure of others. In some cases, we can even speak of systematic practices of multilocality

Enlightenment, Latin America, Age of Revolutions, Spanish America, Brazil

An essay analyzing the effect of Enlightenment thinking on the political and societal elite of the colonial Spanish and Portuguese Americas, and the subsequent colonial revolutions

UT’s Tech Team Moves the Needle Toward Building Optimization

Values at Work Series: Facilities Services developed our core values of Service, Integrity, Teamwork, Excellence, and Stewardship (collectively referred to as SITES) based on the way we approach our work. Our values can be found throughout our areas of services in many ways.Through a series of articles, the Values at Work Series is devoted to providing a closer look at how our values are hard at work. Each article focuses on an area of service and how that group incorporates our values in a significant way. We are proud of our employees who continue to serve as an example of “walking the talk” every day.After facilities managers address their client’s unplanned maintenance issues, provide the necessary preventive maintenance on building systems and manage energy conservation efforts, how do they also find a way to optimize the performance of the buildings on campus so the systems run as well as they ought to...and do it all with limited resources? Building Operations Manager Mark White provides insights into how The University of Texas at Austin, with the help of its Building Optimization Team (BOT), is moving the needle toward impactful facilities optimization on a university campus.Facilities Service

Optimal Unemployment Insurance in an Estimated Job Search Model with Savings

This paper estimates a job search model with savings and determines optimal unemployment benefit policy for the estimated model. For observed and unobserved worker characteristics, the estimation strategy relates observed unemployment spell durations to the model implied unemployment hazard rate. The model is estimated on Danish unemployment spell data which include high quality wealth and income information. The estimation shows that Danish workers respond to changes in economic incentives in ways consistent with the model and that the magnitude of the effect of the responses on the unemployment hazard rate is small. Optimal unemployment benefit level policy is determined as a trade-off between providing insurance against consumption fluctuation and the moral hazard of reducing the worker's incentives to search back into employment. Given the estimated low level of moral hazard, the optimal benefit level is quite high even though workers can self-insure via savings. Depending on the interest rate which is effectively the cost of using savings as self-insurance, the optimal replacement rate ranges between 43% and 82%. The policy analysis emphasizes the importance of including transitional dynamics to avoid a significant downward bias associated with a simple steady state comparison analysis.

On artifact solutions of semi-analytic methods in nonlinear dynamics

Nonlinear dynamics is a topic of permanent interest in mechanics since decades. The authors have recently published some results on a very classical topic, the dynamics of a softening Duffing oscillator under harmonic excitation focusing especially on low-frequency excitation (von Wagner in Arch Appl Mech 86(8):1383–1390, 2016). In this paper, it was shown that classical tools like harmonic balance and perturbation analysis may produce artificial solutions when applied without extra carefulness with respect to parameter ranges in the case of perturbation analysis or prior knowledge about the type of solution in case of harmonic balance. In the present paper these results are shortly summarized as they give the starting point for the additional investigations described herein. First, the method of slowly changing phase and amplitude is reviewed with respect to its capability of determining asymptotic stability of stationary solutions. It is shown that this method can also produce artifact results when applied without extra carefulness. As next example an extended Duffing oscillator is investigated, which shows, if harmonic balance is applied, “islands” of solutions. Using the error criterion in harmonic balance as described in von Wagner (2016) again artifact solutions can be identified

On Artifacts in Nonlinear Dynamics

Nonlinear oscillations are of permanent interest in the field of dynamics of mechanical and mechatronical systems. There exist several well-known semi-analytical methods like Harmonic Balance, perturbation analysis or multiple scales for such problems. We reconsider in our presentation the method of Harmonic Balance but add some additional steps in order to avoid artifacts and get information about the stability. The classical method of Harmonic Balance is therefore added by an error criterion, which considers the neglected terms. Looking on this error for increasing ansatz orders, it can be decided whether a solution exists or is an artifact of the method. For the low error solutions, a stability analysis is performed. As example, an extended Duffing oscillator with additional nonlinear damping and excitation is considered showing regions of separated island solutions. Also a nonlinear piezo-beam energy harvesting system is investigated. The described method enables to calculate solutions in a rapid manner with comparable low effort, to get an overview over regular responses of nonlinear systems.DFG, 253161314, Untersuchung des nichtlinearen dynamischen Verhaltens von stochastisch erregten Energy Harvesting Systemen mittels Lösung der Fokker-Planck-Gleichun

On some aspects of the dynamic behavior of the softening Duffing oscillator under harmonic excitation

The Duffing oscillator is probably the most popular example of a nonlinear oscillator in dynamics. Considering the case of softening Duffing oscillator with weak damping and harmonic excitation and performing standard methods like harmonic balance or perturbation analysis, zero mean solutions with large amplitudes are found for small excitation frequencies. These solutions produce a ”nose-like” curve in the amplitude–frequency diagram and merge with the inclining resonance curve for decreasing (but non-vanishing) damping. These results are presented without any additional discussion in several textbooks. The present paper discusses the accurateness of these solutions by introducing an error estimation in the harmonic balance method showing large errors. Performing a modified perturbation analysis leads to solutions with non-vanishing mean value, showing very small errors in the harmonic balance error analysis

Job Search and Savings: Wealth Effects and Duration Dependence

In this paper we consider a risk averse worker who is moving back and forth between employment and unemployment; layoffs are random and beyond the worker’s influence, while the re-employment chance is directly affected by search effort. We characterize the worker’s optimal savings and job-search behavior as well as the resulting consumption paths and wealth formation. In general, all decisions will depend on the current level of wealth: First, the choice of search effort increases as wealth decreases, a finding which is in accordance with our empirical duration analysis using micro data on unemployment spells. Second, consumption increases with wealth both when the worker is employed and unemployed. Third, savings provide insurane against income fluctuations but this insurance is not perfect; precautionary savings are built up during employment spells and run down during unemployment spells but the consumption path is never going to be completely smooth over states. Finally, our results suggest that the worker’s search intensity and hence the probability of leaving unemployment will exhibit positive duration dependence over unemployment spells via its inverse relationship with the worker’s wealth.Search, consumption smooting, duration dependence