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The children's book "Duck! Rabbit!" dramatizes the lesson that just because one is right, others don’t have to be wrong. An endless dispute is quickly settled once the quarrellers experience an aspect change or gestalt switch and thereby realize that the same picture can be seen in different ways. This simple scenario offers an intriguing model for arbitrating between conflicting positions by going back and forth between different aspects and thereby realizing that conflicting accounts can be equally valid.
Orisa Ibeji
(2014)
Ahmed Yerima's play celebrates the phenomenon of twins among the Yoruba people. Orisa Ibeji is also about man's fear of death and love of life; destiny and reincarnation; and the place of the gods in human affairs. Yerima employs simple and beautiful language, dynamic characters and deft skill to navigate the labyrinth that is Orisa Ibeji.
We develop a model of an order-driven exchange competing for order flow with off-exchange trading mechanisms. Liquidity suppliers face a trade-off between benefits and costs of order exposure. If they display trading intentions, they attract additional trade demand. We show, in equilibrium, hiding trade intentions can induce mis-coordination between liquidity supply and demand, generate excess price fluctuations and harm price efficiency. Econometric high-frequency analysis based on unique data on hidden orders from NASDAQ reveals strong empirical support for these predictions: We find abnormal reactions in prices and order flow after periods of high excess-supply of hidden liquidity.
This is a book about the Tonga of Northern Malawi, sometimes called the Lakeshore Tonga to distinguish them from other ethnic groups with the same name further west in Central Africa. The Lakeshore Tonga were the first ethnic group to identify themselves with the Christian faith. The purpose of the research was to investigate the use of Tonga myths, folktales, proverbs and rituals for their role in Moral Education and assess and evaluate their contribution towards value formation for the youth. Each chapter in the book aims to discuss some ideas in the anthropology of religion and to illustrate them with specific case studies formed primarily through conversation with friends, both young and old, over some years.
The Solvency II standard formula employs an approximate Value-at-Risk approach to define risk-based capital requirements. This paper investigates how the standard formula’s stock risk calibration influences the equity position and investment strategy of a shareholder-value-maximizing insurer with limited liability. The capital requirement for stock risks is determined by multiplying a regulation-defined stock risk parameter by the value of the insurer’s stock portfolio. Intuitively, a higher stock risk parameter should reduce risky investments as well as insolvency risk. However, we find that the default probability does not necessarily decrease when reducing the investment risk (by increasing the stock investment risk parameter). We also find that depending on the precise interaction between assets and liabilities, some insurers will invest conservatively, whereas others will prefer a very risky investment strategy, and a slight change of the stock risk parameter may lead from a conservative to a high risk asset allocation.
Genome-wide association studies are widely used to correlate phenotypic traits with genetic variants. These studies usually compare the genetic variation between two groups to single out certain Single Nucleotide Polymorphisms (SNPs) that are linked to a phenotypic variation in one of the groups. However, it is necessary to have a large enough sample size to find statistically significant correlations. Direct-To-Consumer (DTC) genetic testing can supply additional data: DTC-companies offer the analysis of a large amount of SNPs for an individual at low cost without the need to consult a physician or geneticist. Over 100,000 people have already been genotyped through Direct-To-Consumer genetic testing companies. However, this data is not public for a variety of reasons and thus cannot be used in research. It seems reasonable to create a central open data repository for such data. Here we present the web platform openSNP, an open database which allows participants of Direct-To-Consumer genetic testing to publish their genetic data at no cost along with phenotypic information. Through this crowdsourced effort of collecting genetic and phenotypic information, openSNP has become a resource for a wide area of studies, including Genome-Wide Association Studies. openSNP is hosted at http://www.opensnp.org, and the code is released under MIT-license at http://github.com/gedankenstuecke/snpr.
In this thesis hard probes are studied in the partonic transport model BAMPS (Boltzmann Approach to MultiParton Scatterings). Employing Monte Carlo techniques, this model describes the 3+1 dimensional evolution of the quark gluon plasma phase in ultra-relativistic heavy-ion collisions by propagating all particles in space and time and carrying out their collisions according to the Boltzmann equation. Since hard probes are produced in hard processes with a large momentum transfer, the value of the running coupling is small and their interactions should be describable within perturbative QCD (pQCD). This work focuses on open heavy flavor, but also addresses the suppression of light parton jets, in particular to highlight differences due to the mass. For light partons, radiative processes are the dominant contribution to their energy loss. For heavy quarks, we show that also binary interactions with a running coupling and an improved Debye screening matched to hard-thermal-loop calculations play an important role. Furthermore, the impact of the mass in radiative interactions, prominently named the dead cone effect, and the interplay with the Landau-Pomeranchuk-Migdal (LPM) effect are studied in great detail. Since the transport model BAMPS has access to all medium properties and the space time information of heavy quarks, it is the ideal tool to study the dissociation and regeneration of J/psi mesons, which is also investigated in this thesis.
We study the effect of weakening creditor rights on distress risk premia via a bankruptcy reform that shifts bargaining power in financial distress toward shareholders. We find that the reform reduces risk factor loadings and returns of distressed stocks. The effect is stronger for firms with lower firm-level shareholder bargaining power. An increase in credit spreads of riskier relative to safer firms, in particular for firms with lower firm-level shareholder bargaining power, confirms a shift in bargaining power from bondholders to shareholders. Out-of-sample tests reveal that a reversal of the reform's effects leads to a reversal of factor loadings and returns.
Donald Siegel's 1971 film entitled "The Beguiled" is compared to Tale 1 of Day 3 from Giovanni Boccaccio’s "The Decameron". Both stories are about a man who arrives in a garden setting and finds nine sexually starved women. In Boccaccio's tale, a male gardener finds himself in a convent occupied by nine nuns with whom he proceeds to have sexual relations to everyone's satisfaction. Siegel's film is about a wounded soldier taken in at a girls' finishing school whose nine female residents become the objects of the hero's amorous attention. While Boccaccio adopts a philogynist tone with respect to the material, "The Beguiled" appears to be a virulently misogynist film projecting its female characters as jealous demons who end up mutilating and then killing their male suitor. Findings from evolutionary psychology pertaining to female jealousy and reproductive strategies are used to consider the respective attitudes toward women in the medieval tale and the twentieth-century film. Conclusions are drawn about the difficulty of placing either of the stories within a clear-cut philogynist or misogynist category.
In the framework of an interference setup in which only two outcomes are possible (such as in the case of a Mach–Zehnder interferometer), we discuss in a simple and pedagogical way the difference between a standard, unitary quantum mechanical evolution and the existence of a real collapse of the wavefunction. This is a central and not-yet resolved question of quantum mechanics and indeed of quantum field theory as well. Moreover, we also present the Elitzur–Vaidman bomb, the delayed choice experiment, and the effect of decoherence. In the end, we propose two simple experiments to visualize decoherence and to test the role of an entangled particle.
The osteology of “Coccodus” lindstroemi is studied in detail and it is demonstrated that this species does not belong to the genus Coccodus, but is a rather primitive member of the pycnodontiform family Gladiopycnodontidae. Indeed, the snout of “Coccodus” lindstroemi is elongated in a rostrum formed by the prefrontal and the premaxilla. This rostrum extends beyond the lower jaw level. The toothless premaxilla is sutured by its upper margin to the lower margin of the long and broad prefrontal.
The pectoral fin is lost and replaced by a pectoral spine which articulates on the cleithrum. A long nuchal spine resting on the dermosupraoccipital is present. The body is entirely covered by scales that are flakelike in the abdominal region and scute-like in the caudal region. Joinvillichthys gen. nov. is thus erected
with “Coccodus” lindstroemi as the type species. It is also shown that specimens with dumpier head and body, usually ranged in “Coccodus” lindstroemi, represent another species of the same genus for which the taxon Joinvillichthys kriweti gen. et sp. nov. is created. Specimens sometimes considered as possible juveniles of “Coccodus” lindstroemi form a distinctive new genus and species of gladiopycnodontid fish, Pankowskichthys libanicus gen. et sp. nov. Pankowskichthys differs from Joinvillichthys by many
osteological structures.
The Facility for Antiproton and Ion Research (FAIR), under construction at Darmstadt will provide intense relativistic beams of exotic nuclei at its Superconducting-FRagment Separator. High-resolution in-beam γ-ray spectroscopy will be performed in the HISPEC experiment, using the European Advanced GAmma-ray Tracking Array (AGATA). The PreSPEC-AGATA campaign is the predecessor of HISPEC and runs from 2012 to 2014 at GSI Helmholtzzentrum für Schwerionenforschung GmbH. Up to19 AGATA modules were used at GSI's F Ragment Separator in 2012. We report on the status of the experiment including preliminary results from performance commissioning.
Political theology’s recent rise to academic prominence has, no doubt, been inspired by the sense of a certain staleness of standard (read: Anglo-American) analytical political and legal theory. Especially postcolonial and postmodern philosophy has resuscitated debates about the reality of secularization in Europe, pointing out that much of our shared political metaphysic is indeed that – a metaphysic – with close historical links to debates in theology. That should be no surprise. For almost half a millennium theology stood as the primus inter pares among the three "higher faculties" at European universities. The best minds at work in Europe explained the social and political changes to European audiences within a fully God-centric intellectual universe. Awareness of that fact, as Wim Decock points out in this massive and brilliant work, not only assists us in understanding the development of our political and legal vocabularies. It also enables us to grasp the contingency of our present debates, the way opposite standpoints on political and legal obligation refer back to assumptions about human nature, the roles of individual and society and the nature of "law" that are hard to detach from religious speculation. ...
In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.
Examination of the type material of the forgotten species Liocranum ochraceum Simon, 1867 reveals this species has to be transferred to the genus Anagraphis comb. nov. and that Anagraphis pallida (Hadjissarantos, 1940) is its junior synonym (syn. nov.). Furthermore, the monotypic genus Macedoniella Drensky, 1935 is a junior synonym of Anagraphis and M. karamani a junior synonym of Anagraphis ochraceum (L. Koch, 1867) (syn. nov.).
Three new species of Pachygnatha, P. bispiralis sp. nov., P. intermedia sp. nov. and P. ventricosa sp. nov., are described from forest areas in western Burundi. The presence of P. procincta Bosmans & Bosselaers, 1994 in Burundi confirms its very wide distribution spanning most of Africa.
Pachygnatha appears to be an important element of the afromontane spider fauna.
On January 29, 2014, EU Commissioner Barnier published a draft law proposing a ban for proprietary trading by big banks in Europe. In this opinion piece, published in a German newspaper on 30 January, 2014, Jan Pieter Krahnen, who was a member of the Liikanen Commission, argues that the proposal could prove to be effective in preventing systemic risk.
We examine the impact of so-called "Crisis Contracts" on bank managers' risk-taking incentives and on the probability of banking crises. Under a Crisis Contract, managers are required to contribute a pre-specified share of their past earnings to finance public rescue funds when a crisis occurs. This can be viewed as a retroactive tax that is levied only when a crisis occurs and that leads to a form of collective liability for bank managers. We develop a game-theoretic model of a banking sector whose shareholders have limited liability, so that society at large will suffer losses if a crisis occurs. Without Crisis Contracts, the managers' and shareholders' interests are aligned, and managers take more than the socially optimal level of risk. We investigate how the introduction of Crisis Contracts changes the equilibrium level of risk-taking and the remuneration of bank managers. We establish conditions under which the introduction of Crisis Contracts will reduce the probability of a banking crisis and improve social welfare. We explore how Crisis Contracts and capital requirements can supplement each other and we show that the efficacy of Crisis Contracts is not undermined by attempts to hedge.
Die zentralen Objekte der Dissertation sind Translationsflächen. Dabei handelt es sich um Riemann’sche Flächen, die aus in die euklidische Ebene eingebetteten Polygonen durch Verkleben von parallelen gleichlangen Seiten entstehen. Zwei Translationsflächen sind gleich, wenn es möglich ist, die Polygone durch ”Zerschneiden und mittels Translationen neu Zusammenkleben“ ineinander zu überführen. Die Gruppe GL_2(R) operiert auf der Menge der Translationsflächen via der linearen Abbildungen auf den Polygonen. Der Stabilisator einer Translationsfläche X unter dieser Operation wird die Veech-Gruppe von X genannt und mit SL(X) bezeichnet. Die Veech-Gruppe ist eine diskrete Untergruppe von SL_2(R) und damit eine Fuchs’sche Gruppe.
Fuchs’sche Gruppen werden je nach ihrer Limesmenge in elementare und nicht-elementare Gruppen eingeteilt. Letztere wiederum unterteilt man in Gruppen erster oder zweiter Art. Fuchs’sche Gruppen mit endlichem co-Volumen heißen Gitter und sind genau die endlich erzeugten Gruppen erster Art. Translationsflächen, deren Veech-Gruppe ein Gitter ist, heißen Veech-Flächen und sind von besonderem Interesse, da für sie die Veech Alternative gilt.
Ein feineres Maß für die Größe einer Fuchs’schen Gruppe ist der kritische Exponent. Er ist definiert als das Infimum aller reellen Zahlen, für die die Poincaré Reihe konvergiert und liegt für alle unendlichen Fuchs’schen Gruppen zwischen 0 und 1. Hauptziel der Dissertation ist der Beweis von Theorem 1. Es gibt Translationsflächen, für die der kritische Exponent ihrer Veech-Gruppe echt zwischen 1/2 und 1 liegt.
Der kritische Exponent von elementaren Gruppen ist höchstens 1/2, Translationsflächen mit elementaren Veech-Gruppen sind also als Kandidaten für das Theorem ausgeschlossen. Der kritische Exponent von Gittern ist 1. Also scheiden auch Veech-Flächen für das Theorem aus.
Bis zum Jahr 2003 waren Gitter die einzigen bekannten nicht-elementaren Veech-Gruppen. McMullen klassifizierte die Veech-Flächen vom Geschlecht 2 und zeigte, dass jede solche Fläche, die nur eine Singularität besitzt, in der GL_2(R)-Bahn der Fläche L_D liegt, die aus einem L-förmigen Polygon mit geeigneten von D abhängigen Seitenlängen entsteht.
Während auch heute noch keine Translationsfläche mit Veech-Gruppe zweiter Art bekannt ist, fanden McMullen und unabhängig davon Hubert und Schmidt Konstruktionen unendlich erzeugter Veech-Gruppen erster Art. Eine Abschätzung des kritischen Exponenten dieser Gruppen war 10 Jahre lang eine wichtige offene Frage, die nun durch Theorem 1 beantwortet wird.
Zentral in der Konstruktion von Hubert und Schmidt sind spezielle Punkte, nämlich Verbindungspunkte. Hubert und Schmidt konstruieren Translationsflächen, deren Veech-Gruppen kommensurabel zum Stabilisator SL(X;P) von P sind und damit den gleichen kritischen Exponenten haben. Für Verbindungspunkte mit unendlicher SL(X)- Bahn (diese Punkte heißen nicht-periodisch) ist SL(X;P) unendlich erzeugt und von erster Art.
Wir zeigen Theorem 1, indem wir zeigen, dass für jedes D kongruent 0 mod 4, (kein Quadrat), und jeden nicht-periodischen Verbindungspunkt P in L_D der kritische Exponent der Gruppe SL(L_D;P) echt zwischen 1/2 und 1 liegt.
Eine natürliche Frage in diesem Zusammenhang ist die Abhängigkeit von P: Punkte Q in der SL(L_D)-Bahn von P sind auch er nicht-periodische Verbindungspunkte und die zugehö̈rigen Gruppen SL(L_D;P) und SL(L_D;Q) sind konjugiert zueinander. Daher widmen wir uns in Kapitel 4 der Bestimmung der Bahnen nicht-periodischer Verbindungspunkte.
Die Verbindungspunkte haben die Form P=(x_r+x_iw;y_r+y_iw) mit x_r,x_i,y_r,y_i aus Q. Wir zeigen, dass der Hauptnenner N(P) dieser (gekürzten) Brüche eine Invariante der Bahn ist. Daraus folgt:
Theorem 2. Es gibt unendlich viele verschiedene Bahnen von Verbindungspunkten von L_D.
Wir kennen die Operation der horizontalen und der vertikalen Scherungen A und B aus SL(L_D). Im Spezialfall D=8 erzeugen diese beiden Elemente die ganze Gruppe und wir geben je ein Verfahren an, um eine untere und eine obere Schranke an die Anzahl der Bahnen von nicht-periodischen Verbindungspunkten P mit fixiertem Hauptnenner N(P) zu finden. Damit zeigen wir:
Theorem 3. Die Menge der Verbindungspunkte P mit festem Wert N(P) zerfällt in eine endliche Anzahl von SL(L_8)-Bahnen.
Im Beweis von Theorem 1 ist es nötig, die Nicht-Mittelbarkeit eines Graphen zu zeigen. Da wir nur sehr wenige Informationen über dessen Struktur in unserer konkreten Situation haben, entwickeln wir in Kapitel 1 die folgende Methode:
Theorem 4. Sei G ein Graph, den man durch Weglassen von Kanten in einen Wald G′ ohne Blätter überführen kann, bei dem das Supremum der Längen von zusammenhängenden Valenz-2-Teilgraphen von G′ beschränkt ist. Dann ist G nicht mittelbar.
Um diese Methode anzuwenden, ordnen wir jeder Ecke P von G ein Komplexitätsmaß s(P) zu und weisen nach, dass dieser Wert für die Operation von Worten in A- und B-Potenzen mit wachsender Wortlänge ”tendenziell wächst“.
Panel Sample Selection ModelsThe empirical evidence currently available in the literature regarding the effects of a country's IMF program participation on its output growth is rather inconclusive. In this paper we propose and estimate a panel data sample selection model featuring state dependence. As in this model the output growth effects of program participation can be conditional on the realization of a state variable (conditional pooling), our framework may reconcile previous empirical evidence based on models without state-dependent effects. We find that the effects of IMF program participation on output growth vary systematically with an index reflecting a country's institutional record, and that output growth effects of program participation are significantly positive only if the program participation is coupled with sufficient improvement of the institutional record.