On the initial estimate of interface forces in FETI methods

The Balanced Domain Decomposition (BDD) method and the Finite Element Tearing and Interconnecting (FETI) method are two commonly used non-overlapping domain decomposition methods. Due to strong theoretical and numerical similarities, these two methods are generally considered as being equivalently efficient. However, for some particular cases, such as for structures with strong heterogeneities, FETI requires a large number of iterations to compute the solution compared to BDD. In this paper, the origin of the bad efficiency of FETI in these particular cases is traced back to poor initial estimates of the interface stresses. To improve the estimation of interface forces a novel strategy for splitting interface forces between neighboring substructures is proposed. The additional computational cost incurred is not significant. This yields a new initialization for the FETI method and restores numerical efficiency which makes FETI comparable to BDD even for problems where FETI was performing poorly. Various simple test problems are presented to discuss the efficiency of the proposed strategy and to illustrate the so-obtained numerical equivalence between the BDD and FETI solvers

The Political Economy of Bilateralism and Multilateralism: Institutional Choice in Trade and Taxation

Trade relations are governed by the multilateral GATT, whereas the avoidance of international double taxation rests on a network of around 2000 bilateral treaties. Given the two regimes’ similar economic rationales this difference between bilateralism in international double tax avoidance and multilateralism in the trade regime poses an empirical puzzle. In this paper we develop an answer to this puzzle. Differentiating between different stages of international cooperation, we first describe the institutional form in the bargaining and agreement stages of cooperation. This description shows that the regimes are quite similar in the bargaining stage, both exhibiting a mix of bilateral and multilateral bargaining. However, while agreement is multilateral in the trade regime it is bilateral in taxation. Based on stylized institutional histories of both cases we develop simple game theoretic models incorporating domestic level considerations. Building on these models we then go on to explain the institutional choice between bilateral and multilateral cooperation. We show that state concerns for the distribution of benefits can be best achieved under bilateral bargaining in both regimes. However, in order to lower transaction costs there are also elements of multilateral bargaining. Agreement is multilateral in trade in order to overcome a free-rider problem that results from an interaction of concerns for distribution and enforcement. Since such a problem of free-riding does not exist in taxation, there is no need for binding multilateral agreement.Theories of International Cooperation; International Trade; International Double Taxation; Bilateralism; Multilateralism

The political economy of bilateralism and multilateralism: Institutional choice in international trade and taxation

Trade relations are governed by the multilateral GATT, whereas the avoidance of international double taxation rests on a network of around 2000 bilateral treaties. Given the two regimes similar economic rationales this difference between bilateralism in international double tax avoidance and multilateralism in the trade regime poses an empirical puzzle. In this paper we develop an answer to this puzzle. Differentiating between different stages of international cooperation, we first describe the institutional form in the bargaining and agreement stages of cooperation. This description shows that the regimes are quite similar in the bargaining stage, both exhibiting a mix of bilateral and multilateral bargaining. However, while agreement is multilateral in the trade regime it is bilateral in taxation. Based on stylized institutional histories of both cases we develop simple game theoretic models incorporating domestic level considerations. Building on these models we then go on to explain the institutional choice between bilateral and multilateral cooperation. We show that state concerns for the distribution of benefits can be best achieved under bilateral bargaining in both regimes. However, in order to lower transaction costs there are also elements of multilateral bargaining. Agreement is multilateral in trade in order to overcome a free-rider problem that results from an interaction of concerns for distribution and enforcement. Since such a problem of free-riding does not exist in taxation, there is no need for binding multilateral agreement. -- Während Handelsbeziehungen durch das multilaterale GATT geregelt werden, beruht die Vermeidung internationaler Doppelbesteuerung auf einem Netzwerk von etwa 2000 bilateralen Verträgen. Da beide Regime die gleiche ökonomische Zielsetzung der Marktliberalisierung haben, stellt die unterschiedliche institutionelle Form ein empirisches Puzzle dar, das wir in diesem Papier lösen. Wir unterscheiden zwischen verschiedenen Phasen internationaler Kooperation und beschreiben zunächst die institutionelle Form in der Bargaining- und Agreement-Phase. Es wird gezeigt, dass die Systeme in der Bargaining-Phase sehr ähnlich sind: beide weisen einen Mix bilateraler und multilateraler Elemente auf. In der Agreement-Phase hingegen findet man Multilateralismus im Handelsregime und Bilateralismus im Steuerregime. Im zweiten Teil des Papiers leiten wir aus den nationalen Interessenkonstellationen in der Handels- und Steuerpolitik einfache spieltheoretische Modelle ab, mit deren Hilfe wir die institutionelle Wahl zwischen bilateraler und multilateraler Kooperation in beiden Phasen erklären. Wir zeigen, dass Staaten nach Verteilungsgewinnen streben, was am besten in bilateralen Verhandlungen erreicht werden kann. Bilaterales Verhandeln führt jedoch zu hohen Transaktionskosten, die durch multilaterale Elemente in den Verhandlungen reduziert werden können (Bargaining-Phase). Abkommen in Handelsbeziehungen sind multilateral, um ein free-riding zu vermeiden, das wiederum aus dem Streben nach Verteilungsgewinnen resultiert. Da free-riding im Steuerregime aufgrund der Spielstruktur kein gravierendes Problem ist, gibt es hier keine Notwendigkeit eines multilateralen Abkommens, so dass man hier Bilateralismus vorfindet (Agreement-Phase).

Arteriogenesis versus angiogenesis: similarities and differences

Cardiovascular diseases account for more than half of total mortality before the age of 75 in industrialized countries. To develop therapies promoting the compensatory growth of blood vessels could be superior to palliative surgical surgical interventions. Therefore, much effort has been put into investigating underlying mechanisms. Depending on the initial trigger, growth of blood vessels in adult organisms proceeds via two major processes, angiogenesis and arteriogenesis. While angiogenesis is induced by hypoxia and results in new capillaries, arteriogenesis is induced by physical forces, most importantly fluid shear stress. Consequently, chronically elevated fluid shear stress was found to be the strongest trigger under experimental conditions. Arteriogenesis describes the remodelling of pre-existing arterio-arteriolar anastomoses to completely developed and functional arteries. In both growth processes, enlargement of vascular wall structures was proposed to be covered by proliferation of existing wall cells. Recently, increasing evidence emerges, implicating a pivotal role for circulating cells, above all blood monocytes, in vascular growth processes. Since it has been shown that monocytes/macrophage release a cocktail of chemokines, growth factors and proteases involved in vascular growth, their contribution seems to be of a paracrine fashion. A similar role is currently discussed for various populations of bone-marrow derived stem cells and endothelial progenitors. In contrast, the initial hypothesis that these cells -after undergoing a (trans-)differentiation- contribute by a structural integration into the growing vessel wall, is increasingly challenged

Politicization and institutional (non-)change in international taxation

"Dieses Papier untersucht den institutionellen Wandel des internationalen Steuerregimes in Reaktion auf eine zunehmende Politisierung internationaler Steuerangelegenheiten. Gesellschaftliche Politisierung, die im Bereich der internationalen Besteuerung ein sehr junges Phänomen ist, hat ihre Ursache in einer Governancelücke. Das traditionelle institutionelle Arrangement zur Vermeidung von internationaler Doppelbesteuerung hat nicht-intendierte Nebenfolgen in der Form von schädlichem und unfairem Steuerwettbewerb. Als Reaktion auf dieses Problem haben zivilgesellschaftliche Akteure den Mangel an Effektivität und Fairness skandalisiert. Sie versuchen nationale Regierungen und internationale Organisationen zu mehr internationaler Regulierung des Steuerwettbewerbs anzutreiben. Anders als in Teilen der Literatur angenommen wird, ist die gesellschaftliche Politisierung nicht das Resultat eines Zuwachses an politischem Einfluss von nicht ausreichend legitimierten internationalen Institutionen, sondern sie thematisiert im Gegenteil den Mangel an effektiven internationalen Institutionen. Die zivilgesellschaftlichen Forderungen haben bisher nicht zu institutionellen Reformen geführt. Stattdessen lässt sich lediglich indirekter und inkrementeller Wandel beobachten, der nicht ausreichend ist, um das Problem schädlichen Steuerwettbewerbs zu lösen." (Autorenreferat)"This paper explores the institutional changes of international tax governance in response to growing politicization and contestation of international direct tax issues. I show that politicization – which is a very recent phenomenon in international taxation – results from a governance gap. The traditional setup of international tax cooperation has an unintended consequence in the form of harmful tax competition. In reaction to this problem, civil society groups have begun to question the effectiveness and fairness of the minimal international tax order, lobbying national governments and international organizations for more effective international regulation of tax issues. Thus, in contrast to existing hypotheses, societal politicization does not result from the increasing scope and authority of international institutions, but rather from the lack thereof. However, civil society demands have so far not led to institutional changes in international taxation. Instead, we can only observe indirect and incremental change, which falls short of what would ultimately be needed to address harmful tax competition effectively." (author's abstract

The institutional design of international double taxation avoidance

"Dieser Artikel analysiert die institutionelle Form der internationalen Kooperation zur Vermeidung von Doppelbesteuerung. Es wird argumentiert, dass das Doppelbesteuerungsproblem als ein Koordinationsspiel mit Verteilungskonflikt verstanden werden kann. Die Verteilung der Steuereinnahmen hängt von der Asymmetrie der Investitionsflüsse zwischen den vertragsschließenden Staaten ab. Da diese Investitionspositionen notwendigerweise paarweise variieren, können die Verteilungsinteressen der Staaten am besten in bilateralen Verhandlungen aufeinander abgestimmt werden. Weil es außerdem bei bilateralen Doppelbesteuerungsabkommen keine Externalitäten gibt, sind solche Verträge auch durchsetzbar. Trotzdem gibt es Bedarf für eine multilaterale Organisation, die Informationen und gemeinsame Praktiken in Form eines Modellabkommens verbreitet. Das Modellabkommen dient als Fokalpunkt für die bilateralen Verhandlungen. Die strategische Struktur als Koordinationsspiel kann außerdem erklären, warum die Institutionen der Doppelbesteuerungsvermeidung nicht mit Durchsetzungskapazitäten ausgestattet sind. Das sogenannte Verständigungsverfahren zur Beilegung von Vertragsstreitigkeiten dient vielmehr als Instrument zur Bearbeitung des Problems unvollständiger Verträge." (Autorenreferat)"This article analyzes the institutional design of international double tax avoidance. The basic argument is that double tax avoidance exhibits the strategic structure of a coordination game with a distributive conflict. The distribution of tax revenues depends on the asymmetry of investment flows between treaty partners. Since investment flows are defined dyadically, bilateral bargaining can best accommodate countries' concern for the distribution of tax revenues and other economic benefits connected to the tax base. Moreover, because there are no serious externality problems with bilateral agreement, this solution is also viable. At the same time, there is a need for a multilateral organization to disseminate information and shared practices in the form of a model convention that provides a focal point for bilateral negotiations. The strategic structure of a coordination game can also explain why the institutions of double tax avoidance do not have to be equipped with third-party enforcement capabilities. Instead, the Mutual Agreement Procedure (MAP) is interpreted as a device to deal with the fact that double tax agreements (DTAs) are incomplete contracts." (author's abstract

Species removal and experimental warming in a subarctic tundra plant community

Neighbor interactions are likely to play an important role in subarctic plant communities. We conducted experiments in Interior Alaska in which we crossed species removal with greenhouse warming manipulations. We examined changes in community biomass, and in plant survival and growth of individual species in response to experimental warming and to: (1) removal of whole species versus an equivalent amount of biomass across many species, and (2) removal of subdominant (locally common) versus minor (locally uncommon) plants. Community biomass indicated compensation in growth after removal of minor species and after biomass removal without elimination of entire species, but under-compensation after removal of subdominants. Growth and survival of individual species showed facilitation between some species. Warming increased growth of dominant vascular plants, but at the same time reduced survival, and these impacts were greater for larger, more mesic species than for the smaller species associated with drier habitats. Growth of mosses was reduced by the warming. Removal effects did not differ between warming and ambient conditions. The results indicate that common species are able to reduce resources for others (competitive effect) and increase their growth after neighbor removal, whereas locally uncommon species are not able to respond rapidly to increased resources made available by neighbor removal. Therefore, the impact of the presence of common species on locally uncommon species was facilitative overall, but not vice versa. The balance between disturbances such as changes in temperature and species losses from the community will likely be crucial in determining shifts in subsequent community compositio

Soil erosion and organic carbon export by wet snow avalanches

Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse literature, we sampled sediment concentrations of <i>n</i> = 28 river-spanning snow-avalanche deposits (snow bridges) in the area around Davos, eastern Swiss Alps, and inferred an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km⁻² yr⁻¹, and 0.04 to 131 t C km⁻² yr⁻¹, respectively). A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot scale sample data may be prone to substantial under- or overestimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover

The institutional Design of international double Taxation Avoidance

This article analyzes the institutional design of international double tax avoidance. The basic argument is that double tax avoidance exhibits the strategic structure of a coordination game with a distributive conflict. The distribution of tax revenues depends on the asymmetry of investment flows between treaty partners. Since investment flows are defined dyadically, bilateral bargaining can best accommodate countries’ concern for the distribution of tax revenues and other economic benefits connected to the tax base. Moreover, because there are no serious externality problems with bilateral agreement, this solution is also viable. At the same time, there is a need for a multilateral organization to disseminate information and shared practices in the form of a model convention that provides a focal point for bilateral negotiations. The strategic structure of a coordination game can also explain why the institutions of double tax avoidance do not have to be equipped with third-party enforcement capabilities. Instead, the Mutual Agreement Procedure (MAP) is interpreted as a device to deal with the fact that double tax agreements (DTAs) are incomplete contracts.Double Taxation; Rational Institutional Design, International Political Economy

The political economy of bilateralism and multilateralism : institutional choice in international trade and taxation

Trade relations are governed by the multilateral GATT, whereas the avoidance of international double taxation rests on a network of around 2000 bilateral treaties. Given the two regimes’ similar economic rationales this difference between bilateralism in international double tax avoidance and multilateralism in the trade regime poses an empirical puzzle. In this paper we develop an answer to this puzzle. Differentiating between different stages of international cooperation, we first describe the institutional form in the bargaining and agreement stages of cooperation. This description shows that the regimes are quite similar in the bargaining stage, both exhibiting a mix of bilateral and multilateral bargaining. However, while agreement is multilateral in the trade regime it is bilateral in taxation. Based on stylized institutional histories of both cases we develop simple game theoretic models incorporating domestic level considerations. Building on these models we then go on to explain the institutional choice between bilateral and multilateral cooperation. We show that state concerns for the distribution of benefits can be best achieved under bilateral bargaining in both regimes. However, in order to lower transaction costs there are also elements of multilateral bargaining. Agreement is multilateral in trade in order to overcome a free-rider problem that results from an interaction of concerns for distribution and enforcement. Since such a problem of free-riding does not exist in taxation, there is no need for binding multilateral agreement