More risk - less solidarity? An experimental investigation

A solidarity game was conducted where participants were able to choose between two lotteries with same expected values. However, in one lottery, the risky one, participants faced a higher probability to receive no endowment. The winners were then able to discriminate between subjects risk attitude when it came to voluntary transfers from winners to losers in randomly formed three person groups. The results indicated that risk takers were not fully held responsible for their self-inflicted neediness, although they received on average fewer transfers than non-risk-takers. In fact, group favoritism is observed, where non-risk-takers transferred more to loosing non-risk-takers and risk-takers transferred more to loosing risk-takers. This behavioral pattern was stable across different versions of group compounding, profession and gender. Nevertheless, a gender effect was found with regard to lottery choice and the amount of money transferred. Furthermore, similarities can be seen between the results of the experiment and certain aspects of the current financial crisis. Among them borrowing in non-recourse states in the USA, the role of rating agencies and the hiring of failed CEOs. -- Es wurde ein Solidaritätsspiel durchgeführt, in dem die Teilnehmer aus zwei Lotterien mit gleichen Erwartungswerten wählen konnten. Allerdings war die Wahrscheinlichkeit zu verlieren und keinen Gewinn zu erhalten bei der riskanten Lotterie höher. In Dreiergruppen, bestehend aus Gewinnern und Verlierern, hatten die Gewinner die Möglichkeit freiwillig etwas von ihrem Gewinn an die Verlierer abzugeben. Dabei konnten sie zwischen dem Risikoverhalten der Verlierer unterscheiden. Die Ergebnisse offenbaren, dass risikoreiche Verlierer nicht komplett für ihre selbstverschuldete "Armut" verantwortlich gemacht wurden, obwohl sie im Durchschnitt weniger Transfers erhielten als Verlierer die kein Risiko eingegangen sind. Vielmehr ist ein Favorisieren der eigenen Gruppe zu beobachten, wobei "risikolose Gewinner" mehr an "risikolose Verlierer" transferiert haben und "risikoreiche Gewinner" mehr an "risikoreiche Verlierer" transferierten. Dieses Verhaltensmuster ist stabil über verschiedene Gruppenzusammensetzungen, die fachliche Ausrichtung und das Geschlecht der Teilnehmer des Experiments. Im Gegensatz dazu wurde ein geschlechtsspezifischer Effekt bei der Wahl der Lotterie und bei der Höhe der Transfers beobachtet.

Vallées de débâcle et processus cryokarstiques sur Mars et en Sibérie

Le climat froid et sec de la planète Mars implique le maintien d'un pergélisol. À Yakutsk (Sibérie), l'épaisseur maximale du pergélisol est de 1,5 km. Une analyse comparative entre les vallées de débâcle en Sibérie et celles de la planète Mars est proposée. Elle fait appel au processus d'érosion thermique produit par le contact de l'eau liquide avec le pergélisol. La fonte des glaces de ségrégation sous la vallée implique la formation d'un talik. Celui-ci facilite la prise en charge des sédiments et l'enfoncement de la vallée. En Sibérie, le sapement le long des berges par érosion thermique provoque un rapide recul des versants qui expliquerait la largeur excessive des vallées de débâcle sur Mars. Avec le climat froid de la planète Mars et de la Sibérie, le pergélisol, empêche l'infiltration de l'eau tout en facilitant l'étalement des sédiments à l'embouchure des vallées. La présence de couches massives de glace dans le sous-sol et leurs fontes préférentielles contribue au développement d'un cryokarst comme celui des vallées d'alas en Yakoutie. Une comparaison est proposée entre le cryokarst de la Yakoutie et certaines dépressions fermées sur Mars.The cold and dry climate of the planet Mars involves the existence of permafrost. In Yakutsk (Siberia), the maximum thickness of permafrost if 1.5 km. The objective of this paper is to compare Siberian valleys and Martian outflow channels. The analysis shows comparative thermal erosion by liquid water contact on permafrost. Melting of the segregated ice under the valley floor involves the formation of a talik. Sediment mobilization and incision of the valley will therefore probably be induced. In Siberia thermal erosion of valley walls produces large-scale slumps and favors accelerated scarp retreat. The widening of Martian outflows may best be explained by this process. Under the cold climate conditions of Mars and Siberia, water infiltration is prevented and dispersal of sediments at the mouth of rivers is common. The presence of massive ice and its subsequent thaw contributes to the formation of cryokarst landforms of the alas valley type in Siberia. Cryokarst in Siberia and some circular depressions on Mars are also compared

Experimental Investigation of Gully Formation Under Low Pressure and Low Temperature Conditions

International audienceIntroduction: A large morphological diversity of gullies is observed on Earth and on Mars. Debris flow – a non-newtonian flow comprising a sediment-water mix – is a common process attributed to gully formation on both planets [1, 2]. Many variables can influence the morphology of debris flows (grainsizes, discharge , slope, soil moisture, etc) and their respective influences are difficult to disentangle in the field. Furthermore effects specific to the martian environment have not yet been explored in detail. Some preliminary laboratory simulations have already been performed that isolate some of these variables. Cold room experiments [3] were already perfomed to test the effect of a melted surface layer on the formation of linear gullies over sand dunes. Low pressure experiments [4] were performed to test the effect of the atmospheric pressure on erosional capacity and runout distance of the flows. Our aim is to develop a new set of experiments both under Martian atmospheric pressure and terrestrial atmospheric pressure in order to reproduce the variability of the observed morphologies under well constrained experimental conditions

Ultimate performance of Quantum Well Infrared Photodetectors in the tunneling regime

Thanks to their wavelength diversity and to their excellent uniformity, Quantum Well Infrared Photodetectors (QWIP) emerge as potential candidates for astronomical or defense applications in the very long wavelength infrared (VLWIR) spectral domain. However, these applications deal with very low backgrounds and are very stringent on dark current requirements. In this paper, we present the full electro-optical characterization of a 15 micrometer QWIP, with emphasis on the dark current measurements. Data exhibit striking features, such as a plateau regime in the IV curves at low temperature (4 to 25 K). We show that present theories fail to describe this phenomenon and establish the need for a fully microscopic approach

Solidarity, responsibility and group identity

In the Solidarity Game (Selten and Ockenfels, 1998) lucky winners of a lottery can transfer part of their income to unlucky losers. Will losers get smaller transfers if they can be assumed to be (partly) responsible for their zero income because they have chosen riskier lotteries (Trhal and Radermacher, 2009)? Or will risk-lovers and risk-averters develop group identity feelings, leading to larger transfers within, rather than between, the groups (Chen and Li, 2009, for charitable transfers between and within otherwise defined groups)? In an experiment we find behavior to be guided by in-group favoritism. Responsibility for self-inflicted neediness does not seem to play an important role. In-group/out-group behavior is successfully described by a variant of a social utility function suggested by Cappelen et al. (2010). --risky behavior,group identity,solidarity

Characterization and mapping of surface physical properties of Mars from CRISM multi-angular data: application to Gusev Crater and Meridiani Planum

The analysis of the surface texture from the particle (grain size, shape and internal structure) to its organization (surface roughness) provides information on the geological processes. CRISM multi-angular observations (varied emission angles) allow to characterize the surface scattering behavior which depends on the composition but also the material physical properties (e.g., grain size, shape, internal structure, the surface roughness). After an atmospheric correction by the Multi-angle Approach for Retrieval of the Surface Reflectance from CRISM Observations, the surface reflectances at different geometries are analyzed by inverting the Hapke photometric model depending on the single scattering albedo, the 2-term phase function, the macroscopic roughness and the 2-term opposition effects. Surface photometric maps are created to observe the spatial variations of surface scattering properties as a function of geological units at the CRISM spatial resolution (200m/pixel). An application at the Mars Exploration Rover (MER) landing sites located at Gusev Crater and Meridiani Planum where orbital and in situ observations are available, is presented. Complementary orbital observations (e.g. CRISM spectra, THermal EMission Imaging System, High Resolution Imaging Science Experiment images) are used for interpreting the estimated Hapke photometric parameters in terms of physical properties. The in situ observations are used as ground truth to validate the interpretations. Varied scattering properties are observed inside a CRISM observation (5x10km) suggesting that the surfaces are controlled by local geological processes (e.g. volcanic resurfacing, aeolian and impact processes) rather than regional or global. Consistent results with the in situ observations are observed thus validating the approach and the use of photometry for the characterization of Martian surface physical properties

Orientation and distribution of recent gullies in the southern hemisphere of Mars: observations from HRSC/MEX and MOC/MGS data

Abstract not available

Spatial multi-criteria decision analysis to predict suitability for African swine fever endemicity in Africa

Background African swine fever (ASF) is endemic in several countries of Africa and may pose a risk to all pig producing areas on the continent. Official ASF reporting is often rare and there remains limited awareness of the continent-wide distribution of the disease. In the absence of accurate ASF outbreak data and few quantitative studies on the epidemiology of the disease in Africa, we used spatial multi-criteria decision analysis (MCDA) to derive predictions of the continental distribution of suitability for ASF persistence in domestic pig populations as part of sylvatic or domestic transmission cycles. In order to incorporate the uncertainty in the relative importance of different criteria in defining suitability, we modelled decisions within the MCDA framework using a stochastic approach. The predictive performance of suitability estimates was assessed via a partial ROC analysis using ASF outbreak data reported to the OIE since 2005. Results Outputs from the spatial MCDA indicate that large areas of sub-Saharan Africa may be suitable for ASF persistence as part of either domestic or sylvatic transmission cycles. Areas with high suitability for pig to pig transmission (‘domestic cycles’) were estimated to occur throughout sub-Saharan Africa, whilst areas with high suitability for introduction from wildlife reservoirs (‘sylvatic cycles’) were found predominantly in East, Central and Southern Africa. Based on average AUC ratios from the partial ROC analysis, the predictive ability of suitability estimates for domestic cycles alone was considerably higher than suitability estimates for sylvatic cycles alone, or domestic and sylvatic cycles in combination. Conclusions This study provides the first standardised estimates of the distribution of suitability for ASF transmission associated with domestic and sylvatic cycles in Africa. We provide further evidence for the utility of knowledge-driven risk mapping in animal health, particularly in data-sparse environments.</p