Goldman-Turaev formality from the Knizhnik-Zamolodchikov connection

For an oriented 2-dimensional manifold $\Sigma$ of genus $g$ with $n$ boundary components the space $\mathbb{C}\pi_1(\Sigma)/[\mathbb{C}\pi_1(\Sigma), \mathbb{C}\pi_1(\Sigma)]$ carries the Goldman-Turaev Lie bialgebra structure defined in terms of intersections and self-intersections of curves. Its associated graded (under the natural filtration) is described by cyclic words in $H_1(\Sigma)$ and carries the structure of a necklace Schedler Lie bialgebra. The isomorphism between these two structures in genus zero has been established in [G. Massuyeau, Formal descriptions of Turaev's loop operations] using Kontsevich integrals and in [A. Alekseev, N. Kawazumi, Y. Kuno and F. Naef, The Goldman-Turaev Lie bialgebra in genus zero and the Kashiwara-Vergne problem] using solutions of the Kashiwara-Vergne problem. In this note we give an elementary proof of this isomorphism over $\mathbb{C}$. It uses the Knizhnik-Zamolodchikov connection on $\mathbb{C}\backslash\{ z_1, \dots z_n\}$. The proof of the isomorphism for Lie brackets is a version of the classical result by Hitchin. Surprisingly, it turns out that a similar proof applies to cobrackets.Comment: 12 pages, 1 figure, section 3 adde

Tourism, conflict and contested heritage in former Yugoslavia

Although, historically, there have always been travellers crossing the Balkan Peninsula, Todorova (1994 Todorova, M. (1994). The Balkans: From discovery to invention. Slavic Review, 53, 453–482. doi: 10.2307/2501301) notes that early travellers were usually heading for important centres such as Constantinople or Jerusalem, and considered South-East Europe as a peripheral place where people were just passing through. The region is only really discovered in the eighteenth century along with an increasing interest in the East. More organised forms of tourism appear at the beginning of the nineteenth century, emerging first around railway lines and thermal therapy resources, and then expanding towards the coastlines. A large part of these developments took place in Croatia and the ‘Dalmatian Riviera’, but other regions also experienced the arrival of visitors and the first organised trip in Bosnia was proposed by Thomas Cook & Sons in 1898. It is only after the Second World War, during the rule of Marshall Tito, that tourism really flourished particularly in the period between the 1960s and the 1980s, when the Socialist Federal Republic of Yugoslavia (SFRY) followed an alternative way of development as the rest of the Eastern Bloc. A relative openness to the West allowed the arrival of European tourists and led to forms of mass tourism in some parts of the region (Grandits & Taylor, 2010 Grandits, H., & Taylor, K. (Eds.). (2010). Yugoslavia’s sunny side: A history of tourism and socialism (1950s–1980s). Budapest: CEU Press.). While communist regimes such as Bulgaria and Romania mainly hosted eastern ‘apparatchiks’ on the Black Sea resorts, Yugoslavia and Greece focused on attracting seaside tourists from Western Europe (Cattaruzza & Sintès, 2012 Cattaruzza, A., & Sintès, P. (2012). Atlas géopolitique des Balkans. Un autre visage de l'Europe. Paris: Autrement.)

Measuring Trust: Experiments and Surveys in Contrast and Combination

Trust is a concept that has attracted - significant attention in economic theory and research within the last two decades: it has been applied in a number of contexts and has been investigated both as an explanatory and as a dependent variable. In this paper, we explore the questions of what exactly is measured by the diverse survey-derived scales and experiments claiming to measure trust, and how these different measures are related. Using nationally representative data, we test a commonly used experimental measure of trust for robustness to a number of interferences, finding it to be mostly unsusceptible to stake size, the extent of strategy space, the use of the strategy method, and the characteristics of the experimenters. Inspired by criticism of the widespread trust question used in many surveys, we created a new, improved survey trust scale consisting of three short statements. We show that the dimension of this scale is distinct from trust in institutions and trust in known others. Our new scale is a valid and reliable measure of trust in strangers. The scale is valid in the sense that it correlates with trusting behaviour in the experiment. Furthermore, we demonstrate that the test-retest reliability of six weeks is high. The experimental measure of trust is, on the other hand, not significantly correlated with trust in institutions nor with trust in known others. We therefore conclude that the experimental measure of trust refers not to trust in a general sense, but specifically to trust in strangers.Trust, experiment, survey, representativity, SOEP

Measuring Trust: Experiments and Surveys in Contrast and Combination

Trust is a concept that has attracted significant attention in economic theory and research within the last two decades: it has been applied in a number of contexts and has been investigated both as an explanatory and as a dependent variable. In this paper, we explore the questions of what exactly is measured by the diverse survey-derived scales and experiments claiming to measure trust, and how these different measures are related. Using nationally representative data, we test a commonly used experimental measure of trust for robustness to a number of interferences, finding it to be mostly unsusceptible to stake size, the extent of strategy space, the use of the strategy method, and the characteristics of the experimenters. Inspired by criticism of the widespread trust question used in many surveys, we created a new, improved survey trust scale consisting of three short statements. We show that the dimension of this scale is distinct from trust in institutions and trust in known others. Our new scale is a valid and reliable measure of trust in strangers. The scale is valid in the sense that it correlates with trusting behaviour in the experiment. Both survey and experimental measure correlate with related factors such as risk aversion, being an entrepreneur or a shareholder. Furthermore, we demonstrate that the survey measure's test-retest reliability (six weeks) is high. The experimental measure of trust is, on the other hand, not significantly correlated with trust in institutions nor with trust in known others. We conclude that the experimental measure of trust refers not to trust in a general sense, but specifically to trust in strangers.representativity, survey, experiment, trust, SOEP

The Role of Equality and Efficiency in Social Preferences

Engelmann and Strobel (AER 2004) claim that a combination of efficiency seeking and minmax preferences dominates inequity aversion in simple dictator games. This result relies on a strong subject pool effect. The participants of their experiments were undergraduate students of economics and business administration who self-selected into their field of study and learned early on that efficiency is desirable. We show that for non-economists the preference for efficiency is much less pronounced. We also find a gender effect indicating that women are more egalitarian than men. However, perhaps surprisingly, the dominance of equality over efficiency is unrelated to political attitudes

Giant Planet Formation by Core Accretion

We present a review of the standard paradigm for giant planet formation, the core accretion theory. After an overview of the basic concepts of this model, results of the original implementation are discussed. Then, recent improvements and extensions, like the inclusion of planetary migration and the resulting effects are discussed. It is shown that these improvement solve the timescale problem. Finally, it is shown that by means of generating synthetic populations of (extrasolar) planets, core accretion models are able to reproduce in a statistically significant way the actually observed planetary population.Comment: 8 pages, 3 figures, invited review, to appear in "Extreme Solar Systems" ASP Conference Series, eds. Debra Fischer, Fred Rasio, Steve Thorsett and Alex Wolszcza

Thermodynamics of RNA/DNA hybridization in high density oligonucleotide microarrays

We analyze a series of publicly available controlled experiments (Latin square) on Affymetrix high density oligonucleotide microarrays using a simple physical model of the hybridization process. We plot for each gene the signal intensity versus the hybridization free energy of RNA/DNA duplexes in solution, for perfect matching and mismatching probes. Both values tend to align on a single master curve in good agreement with Langmuir adsorption theory, provided one takes into account the decrease of the effective target concentration due to target-target hybridization in solution. We give an example of a deviation from the expected thermodynamical behavior for the probe set 1091\_at due to annotation problems, i.e. the surface-bound probe is not the exact complement of the target RNA sequence, because of errors present in public databases at the time when the array was designed. We show that the parametrization of the experimental data with RNA/DNA free energy improves the quality of the fits and enhances the stability of the fitting parameters compared to previous studies.Comment: 11 pages, 16 figures - final version as publishe