Search

The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the $^{222}$Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a $^{222}$Rn activity concentration of 10 $\mu$Bq/kg in 3.2 t of xenon. The knowledge of the distribution of the $^{222}$Rn sources allowed us to selectively eliminate critical components in the course of the experiment. The predictions from the emanation measurements were compared to data of the $^{222}$Rn activity concentration in XENON1T. The final $^{222}$Rn activity concentration of (4.5 $\pm$ 0.1) $\mu$Bq/kg in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment., Comment: 14 pages, 3 figures

The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $^{136}$Xe. Out of its 50$\,$t total natural xenon inventory, 40$\,$t will be the active target of a time projection chamber which thus contains about 3.6 t of $^{136}$Xe. Here, we show that its projected half-life sensitivity is $2.4\times10^{27}\,$yr, using a fiducial volume of 5t of natural xenon and 10$\,$yr of operation with a background rate of less than 0.2$~$events/(t$\cdot$yr) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $^{136}$Xe., 12 pages, 9 figures

This article asks why ethnic exclusion from executive-level state power leads to armed conflict in some cases but not in others. To resolve this puzzle, it focuses on the possible role of five additional, qualitatively coded factors that have been considered by either grievance or opportunity theories of civil war but for which quantitative data are not readily available. To assess the combined relevance of these factors, the authors use qualitative comparative analysis (QCA) to explore the diverging conflict trajectories of 58 ‘most similar’ ethnic groups. These groups have a uniformly high conflict propensity because they are politically excluded, situated in poor countries, live geographically concentrated, and comprise substantial parts of the population; yet, only 25 of them actually experienced violent conflict. The results show that the resentment created by ethno-political exclusion translates into violent conflict if the state reacts against initial protests and mobilization with indiscriminate violence, and if there is a refuge area either within or outside the country that allows regime opponents to organize armed resistance. Moreover, a more processual analysis of conflict dynamics reveals that the conditions conducive to ethnic rebellion appear in a particular temporal sequence with a clear and universal escalation pattern.

Green technologies display unusually strong growth and are well on the way to establishing a ‘mega-trend’ in technology development. To exploit the associated economic opportunities, many industrialised countries have started to follow an innovation-oriented approach to environmental policy. Against this background, the ways are examined in which environmental policy can effectively ‘govern’ technological change and secure environmental improvements. What is needed is a clear focus on prioritising the ecological effectiveness of environmental innovations, devising ‘smart regulation’ through instrument mixes and addressing the inherent limitations of innovation-oriented policies.

International river basins are mostly characterized by upstream-downstream externalities that involve asymmetric incentives to cooperate and, therefore, suggest a high conflict potential between riparian states. However, with more than 400 river basin treaties, cooperation along international rivers by far outweighs water-related conflicts. The abundance of international water cooperation despite the odds is puzzling and has so far received little systematic attention. Against this background, I develop a research framework that draws on international regime theory and combines power, interest, knowledge and contextbased approaches to water regime formation. In a second step, I probe the plausibility of my framework in two case studies on international water cooperation in the Rhine and Elbe river basins. The empirical findings suggest that there is no “one-answer-fits-all” in trying to explain water regime formation. While power-based approaches are of limited explanatory value, a thorough understanding of cooperation along the two international rivers requires the combination of interest, knowledge and context-based arguments.

User Experience Design (UXD) incorporates the increasing importance of emotional aspects in user product interaction and aims at creating holistic experiences. In UXD teams, members with various competences and tasks have to collaborate towards a common experience goal. Roles define which tasks and competences are required. Linking requirements from traditional product development and UXD, we defined an UXD role model in a previous project. Nevertheless, UXD is a rather young dis-cipline within product development. But creating experiences is a traditional focus of other disciplines outside engineering de-sign. We aim at transferring knowledge from those disciplines to support the design of fascinating User Experience. We identi-fied relevant experience disciplines and selected the four most promising ones for our analysis: game development, film produc-tion, tourism and marketing. Based on an interview study we analyzed a broad range of roles. We joined the main insights into the existing UXD role model – confirming and enriching exiting roles and introducing the new role of an Experience Author. Our approach widens the scope of experience designers and supports product development teams by providing required roles on the way to User Experience.

This article asks why ethnic exclusion from executive-level state power leads to armed conflict in some cases but not in others. To answer this question the author develops a nine-factor model of ethnic conflict, which is used to investigate the diverging conflict trajectories of two pairs of ‘most similar’ ethnic groups. These include the Malinke in Guinea and Northerners in Cote d'Ivoire on the one hand, and Kurds in Syria and Turkey on the other. It is shown that varying responses to ethnic exclusion can mainly be traced back to three factors, which have so far been neglected in the ethnic conflict literature: the selectivity of state violence, the territorial reach of the state and the availability of cross-border sanctuaries. Ethnic rebellion occurs where weak territorial control and indiscriminate repression combine with external sanctuary. Conversely, violent escalation is avoided in a context of strong territorial control, selective repression and no external sanctuary.

In the context of the widespread ‘resurgence’ of traditional authorities in Africa, increasing attention has been devoted to the manner in which the institutions of the state combine with those of non-state authorities. While much of the debate has been focused on the implications for democracy, this paper addresses the relationship between traditional resurgence and violent conflict. An analytical framework that distinguishes between ‘institutional hybridity’ and different forms of ‘institutional multiplicity’ is presented. This is then explored through a case study of the Buganda Kingdom in Uganda, where institutional disputes over land and decentralisation can be linked to the violence between state forces and Kingdom supporters that erupted in 2009. The analysis underscores the importance of careful institutional analysis in cases of traditional resurgence in order to mitigate violent conflict outcomes.

The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, was designed to search for evidence of dark matter interactions inside a volume of liquid xenon using a dual-phase time projection chamber. This paper describes the Slow Control System (SCS) of the experiment with emphasis on the distributed architecture as well as on its modular and expandable nature. The system software was designed according to the rules of Object-Oriented Programming and coded in Java, thus promoting code reusability and maximum flexibility during commissioning of the experiment. The SCS has been continuously monitoring the XENON100 detector since mid 2008, remotely recording hundreds of parameters on a few dozen instruments in real time, and setting emergency alarms for the most important variables., Comment: 12 pages, 4 figures

Though military interventions seem endemic in sub-Saharan Africa, more than a third of all countries have been able to avoid military coups. To solve this puzzle, this article relates the likelihood of military coups to the degree of ethnic congruence between civilian and military leaders, arguing that coup avoidance is most likely when government and army either exhibit the same ethnic bias or are both ethnically balanced. This argument is illustrated by a comparison of the diverging experiences of Zambia and Uganda. While Zambia is among Africa’s coup-free countries, Uganda’s vulnerability to military intervention has varied over time – with four coups under Obote and the Uganda National Liberation Front (UNLF) but no coups under Amin and Museveni. Drawing on original longitudinal data on the ethnic distribution of political and military posts, the article shows that the absence of military coups in Zambia goes back to the balanced composition of government and army. In Uganda, coup avoidance under Amin and Museveni can be linked to the fact that government and army exhibited the same ethnic bias, whereas the coups against the Obote and UNLF regimes reflected either ethnic incongruence between civilian and military leaders or the destabilising combination of a similarly polarised government and army., Politische Interventionen von Militärs scheinen im subsaharischen Afrika allgegenwärtig zu sein. In mehr als einem Drittel der afrikanischen Staaten kam es jedoch bislang nicht zu einem Militärputsch. Der Autor dieses Beitrags vermutet eine Verbindung zwischen dem Grad ethnischer Kongruenz in der zivilen und der militärischen Führung eines Staates und der Wahrscheinlichkeit von Militärinterventionen; er argumentiert, dass ein Putsch immer dann vermieden werden kann, wenn Regierung und militärische Führung entweder von der gleichen ethnischen Gruppe dominiert werden oder wenn beide ethnisch ausgewogen zusammengesetzt sind. Dieser Erklärungsansatz wird an einer vergleichenden Fallstudie zu Sambia und Uganda empirisch überprüft. Während es in Sambia bislang keinen Militärputsch gab, war Uganda im Zeitverlauf unterschiedlich stark anfällig für politische Interventionen des Militärs – es kam zu insgesamt vier Militärputschen gegen Obote und die Uganda National Liberation Front (UNLF), nicht aber gegen Amin und Museveni. Auf der Grundlage umfangreicher Primärdaten zur ethnischen Verteilung von Staatsämtern und hohen militärischen Funktionen führt der Autor das Ausbleiben von Militärputschen in Sambia auf die ethnisch ausgewogene Zusammensetzung von Regierung und Militär zurück. Im Fall von Uganda erklärt er das Ausbleiben erfolgreicher Putsche unter Amin und Museveni vor allem dadurch, dass die Schaltstellen politischer und militärischer Macht jeweils von Mitgliedern derselben ethnischen Gruppe dominiert waren. Demgegenüber führt der die Militärputsche gegen Obote und die UNLF entweder auf die Inkongruenz der ethnischen Balance innerhalb der jeweiligen politischen und militärischen Elite zurück oder auf die destabilisierende Kombination einer ethnisch ähnlich stark polarisierten Zusammensetzung von Regierung und Armee.

The basin scale has been promoted universally as the optimal management unit that allows for the internalization of all external effects caused by multiple water uses. However, the basin scale has been put forward largely on the basis of experience in temperate zones. Hence whether the basin scale is the best scale for management in other settings remains questionable. To address these questions this paper analyzes the economic viability and the political feasibility of alternative management options in the Kidron/Wadi Nar region. The Kidron/Wadi Nar is a small basin in which wastewater from eastern Jerusalem flows through the desert to the Dead Sea. Various options for managing these wastewater flows were analyzed ex ante on the basis of both a cost benefit and a multi-criteria analysis. The paper finds that due to economies of scale, a pure basin approach is not desirable from a physical and economic perspective. Furthermore, in terms of political feasibility, it seems that the option which prompts the fewest objections from influential stakeholder groups in the two entities under the current asymmetrical political setting is not a basin solution either, but a two plant solution based on an outsourcing arrangement. These findings imply that the river basin management approach can not be considered the best management approach for the arid transboundary case at hand, and hence is not unequivocally universally applicable.

Western donors recognize that the challenge of achieving adequate water service delivery at worldwide scale is closely linked to the problem of state fragility and seek guidance on how to deliver services more effectively. This study takes the example of German donor support to the water sector of Yemen and identifies lessons for good international engagement in fragile states. While Yemen has recently made important progress in the institutional and organizational consolidation of the water sector, its performance in terms of water policy development and implementation is still weak and the overall structures remain largely unsustainable. German development cooperation has taken up this challenge by devising a “multi-level strategy” that combines support to sectoral reform at the macro and meso level with the creation of decentralized and commercialized service utilities at the micro level. Specific “lessons learned” from German donor involvement in the Yemenite water sector include the need for (1) context sensitivity, (2) state building through intervention at different levels, (3) dialogue and participation, (4) conflict prevention, (5) alignment with local priorities, and (6) donor coordination.