The evolutionary history of the Arabidopsis arenosa complex : diverse tetraploids mask the Western Carpathian center of species and genetic diversity

The Arabidopsis arenosa complex is closely related to the model plant Arabidopsis thaliana. Species and subspecies in the complex are mainly biennial, predominantly outcrossing, herbaceous, and with a distribution range covering most parts of latitudes and the eastern reaches of Europe. In this study we present the first comprehensive evolutionary history of the A. arenosa species complex, covering its natural range, by using chromosome counts, nuclear AFLP data, and a maternally inherited marker from the chloroplast genome [trnL intron (trnL) and trnL/F intergenic spacer (trnL/F-IGS) of tRNALeu and tRNAPhe, respectively]. We unravel the broad-scale cytogeographic and phylogeographic patterns of diploids and tetraploids. Diploid cytotypes were exclusively found on the Balkan Peninsula and in the Carpathians while tetraploid cytotypes were found throughout the remaining distribution range of the A. arenosa complex. Three centers of genetic diversity were identified: the Balkan Peninsula, the Carpathians, and the unglaciated Eastern and Southeastern Alps. All three could have served as long-term refugia during Pleistocene climate oscillations. We hypothesize that the Western Carpathians were and still are the cradle of speciation within the A. arenosa complex due to the high species number and genetic diversity and the concurrence of both cytotypes there

Bandits in the Lab

We test Keller, Rady, Cripps’ (2005) game of strategic experimentation with exponential bandits in the laboratory. We find strong support for the prediction of free-riding because of strategic concerns. We also find strong evidence for behavior that is characteristic of Markov perfect equilibrium: non-cutoff behavior, lonely pioneers and frequent switches of action

Simulative investigation of required spatial source resolution in directional room impulse response measurements

International audienceIn classical and standardized room acoustic measurements, the directivity of sources and receivers is either not considered, specified to be omnidirectional for inter-measurement comparability, or for the receiver defined as HRTF or spatial audio formats. These room impulse response (RIR) measurements allow for the analysis of certain aspects of an acoustic scene. Parameters such as Early Decay Time (EDT) attempt to reflect the listening impression, while others such as the reverberation time serve as physical descriptors and for the evaluation of rooms for different purposes. The explicit non-consideration of the source and receiver directivity waives an abundance of information, which is essential for a complete description of the spatial composition of an acoustic scene, for example in an auralization. On the one hand, a more complete description raises the degree of realism in auralizations, presumably intensifying the immersion of human listeners. On the other hand, the freedom of arbitrary source-receiver directivity combinations opens up the possibility of directional acoustical analysis like scanning single reflection paths within a room.For the measurement of directional room impulse responses (DRIR) several measurement methods and instruments have been implemented in the past. Most of them aim either at fast measurements or at measurements of a high spatial resolution. The compromise of obtaining a sufficiently high resolution in an acceptable time usually is often disregarded due to the ambiguous definition of a sufficiently high resolution.Before the development of suitable methods and instruments, the importance of directivity in an acoustical scene has to be determined. This entails the question if and up to which complexity the measurement of directional room impulse responses offers an advantage for room representations in auralizations and for parametric room acoustic descriptions.A sufficiently high resolution can be defined in many ways, either in regard to just noticeable differences for human listeners, or objectively regarding the effects on technical parameters. This work investigates the effect of the source directivity resolution on room acoustical parameters. Since real measurements contain too many uncontrollable influences such as time variances and sources that can radiate the required directivity with a sufficient precision do not yet exist, this investigation is done using room acoustic simulations.First, the modelling of suitable artificial directivity will be explained. The spatial resolution will be denoted by the corresponding spherical harmonic order. The goal is a directivity with a minimum beam width for each given spherical harmonic order without strong side lobes. This characteristic represents the worst case for each resolution. The generated source directivity will then be used in hybrid ray tracing and image source room acoustic simulations in three rooms of different size and acoustic property. This approach allows a more generally valid statement about the impact of the source directivity.The results will be discussed using the impact on objective room acoustic parameters as an indicator for the required spatial source resolution. Subjective parameters will be considered as an outlook towards the impact on the human perception. The findings are meant to aid the design of measurement instruments for directional room impulse response measurement in reasonable measurement times with a sufficiently high spatial resolution

Generalized Trust in the Mirror: An Agent-Based Model on the Dynamics of Trust

High levels of trust have been linked to a variety of benefits including the well-functioning of markets and political institutions or the ability of societies to solve public goods problems endogenously. While there is extensive literature on the macro-level determinants of trust, the micro-level processes underlying the emergence and stability of trust are not yet sufficiently understood. We address this lacuna by means of a computer model. In this paper, conditions under which trust is likely to emerge and be sustained are identified. We focus our analysis mainly on the individual characteristics of agents: their social or geographical mobility, their attitude towards others or their general uncertainty about the environment. Contrary to predictions from previous literature, we show that immobile agents are detrimental to both, the emergence and robustness of trust. Additionally, we identify a hidden link between trusting others and being trustworthy

Gold-Catalyzed Direct C(sp³)−H Acetoxylation of Saturated Hydrocarbons

In this communication we report our studies towards the development of a gold-catalyzed direct acetoxylation of C(sp3)−H bonds. We achieve this through the use of the hypervalent iodine reagent PhI(OAc)2 in combination with a simple gold salt (HAuBr4) as the catalyst. Through a comparison of the reactivities of cyclooctane and adamantane we judge the reaction to proceed via hydride transfer. This is further substantiated through computational studies of the relative energies for the anions, radicals and cations derived from C−H bond cleavage of cyclooctane and adamantane relevant to the C−H cleaving step

Agent-Based Modeling in Social Science, History, and Philosophy: An Introduction

Agent-based modeling has become a common and well-established tool in the social sciences and certain of the humanities. Here, we aim to provide an overview of the different modeling approaches in current use. Our discussion unfolds in two parts: we first classify different aspects of the model-building process and identify a number of characteristics shared by most agent-based models in the humanities and social sciences; then we map relevant differences between the various modeling approaches. We classify these into different dimensions including the type of target systems addressed, the intended modeling goals, and the models’ degree of abstraction. Along the way, we provide reference to related debates in contemporary philosophy of science

Participatory experimentation on a climate street

Cities' role in addressing both climate change mitigation and adaptation is becoming increasingly important. Within the last decade, cities together with other actors have initiated neighborhood-level climate change projects that build on the concept of experimentation using participation and coproduction. Common features in these initiatives are the limitation of the project to a geographically specific area within the city, inclusion of stakeholders from that physical location, and the use of different types of experimentation through participation in order to pursue climate objectives. This qualitative case study discusses the participatory experimentation and potential structural transformations by focusing on the Climate Street project of Helsinki and Vantaa, Finland. More specifically, we examine how learning, participation, and public visibility contribute toward the impact of the project. Our results show that existing urban governance structures restrict experiments in many ways and only certain types of change are feasible. This implies that while participatory experimentation offers promise but is not a panacea in terms of governing climate change.Peer reviewe

Couple relationships and health: the role of the individual's and the partner's education

A positive correlation between couple relationships and health is well established. However, recent studies indicate that the beneficial effects of couple relationships on health vary substantially according to the characteristics of the relationship and of the partners involved. The present paper examines to what extent partnership effects on physical and mental health differ based on the individual’s education, the partner's education and educational homogamy between partners. Our database is the German Socio-Economic Panel for the period of 2002 to 2016. Based on fixed effects analysis, our results show that a highly educated partner is more beneficial for mental and physical health than a partner with low education. In contrast, the effects of partnerships on health do not depend on whether the partners have same or different educational levels. The results also indicate that partnership effects on health depend on mate choice and on the potential to find a highly educated partner. Education-specific partnership effects on mental health are more prevalent for women, and effects on physical health are more prevalent for men.Ein positiver Zusammenhang zwischen Partnerschaft und Gesundheit ist lange bekannt. Neuere Studien zeigen jedoch, dass die Gesundheitseffekte von Paarbeziehungen von den Eigenschaften der Beziehung und den Eigenschaften der Partner abhängen. Der Beitrag untersucht, ob und inwieweit die Einflüsse einer Paarbeziehung auf die physische und die mentale Gesundheit vom Bildungsniveau des Individuums, dem seines Partners und von der Bildungshomogamie abhängen. Mithilfe von Fixed-Effects-Modellen werden Daten des Sozioökonomischen Panels (SOEP, Wellen 2002-2016) analysiert. Die Ergebnisse zeigen, dass ein Partner mit hoher Bildung der mentalen und physischen Gesundheit förderlicher ist als ein Partner mit niedriger Bildung. Die Gesundheitseffekte von Paarbeziehungen sind jedoch unabhängig vom Ausmaß der Bildungshomogamie bzw. -heterogamie. Die Ergebnisse weisen darauf hin, dass die Gesundheitseffekte einer Partnerschaft von den Chancen abhängen, einen hoch gebildeten Partner zu finden. Die bildungsabhängigen Partnerschaftseffekte auf die mentale Gesundheit sind stärker bei Frauen ausgeprägt, bildungsabhängige Partnerschaftseffekte auf die physische Gesundheit finden sich dagegen eher bei Männern

Agent-Based Modeling in Social Science, History, and Philosophy: An Introduction

Agent-based modeling has become a common and well-established tool in the social sciences and certain of the humanities. Here, we aim to provide an overview of the different modeling approaches in current use. Our discussion unfolds in two parts: we first classify different aspects of the model-building process and identify a number of characteristics shared by most agent-based models in the humanities and social sciences; then we map relevant differences between the various modeling approaches. We classify these into different dimensions including the type of target systems addressed, the intended modeling goals, and the models’ degree of abstraction. Along the way, we provide reference to related debates in contemporary philosophy of science

Hot or not – Which features make FinTechs attractive for investors?

Attracting investors and generating funding is a key issue for all start-ups. The information asymmetries between investor and start-up need to be reduced. Despite the overwhelming literature on venture capital financing and different signals reflecting venture quality, pinpointing the signals which impact funding decisions remains an open issue. This study presents an empirical examination of the effectiveness of different signals to convince investors and generate funding. We examine the impact of signals concerning venture quality (classic ones such as human capital, intellectual capital and social alliance/network capital as well as the strategic orientation in terms of business model patterns. Based on a comprehensive sample of more than 101 German FinTechs, our study delivers empirical evidence that human capital as well as the strategic orientation positively impacts a FinTech’s attractiveness. However, our chosen measures for intellectual capital and social network/alliance capital result in negative effects