Efficient Coordination in Weakest-Link Games

Existing experimental research on behavior in weakest-link games shows overwhelmingly the inability of people to coordinate on the efficient equilibrium, especially in larger groups. We hypothesize that people will be able to coordinate on efficient outcomes, provided they have sufficient freedom to choose their interaction neighborhood. We conduct experiments with medium sized and large groups and show that neighborhood choice indeed leads to coordination on the fully efficient equilibrium, irrespective of group size. This leads to substantial welfare effects. Achieved welfare is between 40 and 60 percent higher in games with neighborhood choice than without neighborhood choice. We identify exclusion as the simple but very effective mechanism underlying this result. In early rounds, high performers exclude low performers who in consequence ‘learn’ to become high performers.efficient coordination, weakest-link, minimum effort, neighborhood choice, experiment

Quasi-free Standing Epitaxial Graphene on SiC by Hydrogen Intercalation

Quasi-free standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the 6root3 reconstructed initial carbon layer and the SiC substrate. The topmost Si atoms which for epitaxial graphene are covalently bound to this buffer layer, are now saturated by hydrogen bonds. The buffer layer is turned into a quasi-free standing graphene monolayer with its typical linear pi-bands. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation is stable in air and can be reversed by annealing to around 900 degrees Celsius.Comment: Accepted for publication in Physical Review Letter

Erythrozytäre Blutgruppen-Polymorphismen – Pathogenetisch relevanter Faktor für mikrovaskuläre inflammatorische Prozesse?:Pilotstudie am Modell des mikroangiopathischen Schlaganfalls

Erytrozytäre Membranglykoproteine, die Blutgruppen-Polymorphismen tragen, haben funktionelle physiologische Bedeutung. Die untersuchten Blutgruppen-Polymorphismen Duffy, Indian, Cromer, Lutheran und CD47 haben eine bekannte immunologische Funktion. Bei Patienten mit mikroangiopathischen Schlaganfall, dem pathogenetisch eine zerebrale Mikroangiopathie mit endothelialer Dysfunktion und entzündlicher Komponente zu Grunde liegt, wurde die Allelverteilung der im Vergleich zur Allelverteilung bei gesunden Probanden untersucht. Für die Polymorphismen in den Blutgruppenantigensystemen Indian (IN), Cromer (CROM), Lutheran (LU) sowie für das Protein CD47 ergaben sich für das eingesetzten Patientenkollektiv kein signifikanten Unterschied sowohl in der Genotypverteilung als auch in der Allelverteilung. Es ließ sich jedoch ein Trend mit grenzwertiger statistischer Signifikanz hinsichtlich der Verteilung der Allele des Duffy Polymorphismus nachweisen

Sleep apnea-hypopnea quantification by cardiovascular data analysis

Sleep disorders are a major risk factor for cardiovascular diseases. Sleep apnea is the most common sleep disturbance and its detection relies on a polysomnography, i.e., a combination of several medical examinations performed during a monitored sleep night. In order to detect occurrences of sleep apnea without the need of combined recordings, we focus our efforts on extracting a quantifier related to the events of sleep apnea from a cardiovascular time series, namely systolic blood pressure (SBP). Physiologic time series are generally highly nonstationary and entrap the application of conventional tools that require a stationary condition. In our study, data nonstationarities are uncovered by a segmentation procedure which splits the signal into stationary patches, providing local quantities such as mean and variance of the SBP signal in each stationary patch, as well as its duration L. We analysed the data of 26 apneic diagnosed individuals, divided into hypertensive and normotensive groups, and compared the results with those of a control group. From the segmentation procedure, we identified that the average duration 〈L〉, as well as the average variance 〈σ2〉, are correlated to the apnea-hypoapnea index (AHI), previously obtained by polysomnographic exams. Moreover, our results unveil an oscillatory pattern in apneic subjects, whose amplitude S∗ is also correlated with AHI. All these quantities allow to separate apneic individuals, with an accuracy of at least 79%. Therefore, they provide alternative criteria to detect sleep apnea based on a single time series, the systolic blood pressure

Be nice if you have to — the neurobiological roots of strategic fairness

Social norms, such as treating others fairly regardless of kin relations, are essential for the functioning of human societies. Their existence may explain why humans, among all species, show unique patterns of prosocial behaviour. The maintenance of social norms often depends on external enforcement, as in the absence of credible sanctioning mechanisms prosocial behaviour deteriorates quickly. This sanction-dependent prosocial behaviour suggests that humans strategically adapt their behaviour and act selfishly if possible but control selfish impulses if necessary. Recent studies point at the role of the dorsolateral prefrontal cortex (DLPFC) in controlling selfish impulses. We test whether the DLPFC is indeed involved in the control of selfish impulses as well as the strategic acquisition of this control mechanism. Using repetitive transcranial magnetic stimulation, we provide evidence for the causal role of the right DLPFC in strategic fairness. Because the DLPFC is phylogenetically one of the latest developed neocortical regions, this could explain why complex norm systems exist in humans but not in other social animals

A Psychological Autopsy of an Intellectually Gifted Student With Attention Deficit Disorder

A psychological autopsy of an18-year-old male with dual exceptionalities contributes to our understanding of suicide among students with gifts and talents. Using four theories and models of suicide and research on the lived experience of students with gifts and talents, a comprehensive analysis of this adolescent’s life offers implications for future suicide prevention among these students. Schools that are unprepared for exceptional students (gifted and/or 2e) may contribute to students’ distress. Professional development and adequate resources focused on the unique needs of exceptional students will promote a responsive environment for students’ positive psychosocial development. Parents, educators and counselors need information and strategies for responding to community members in distress. Such knowledge can foster the necessary positive attitudes toward evidence-based treatment for conditions that affect wellbeing. The importance of limiting access to lethal means among persons in distress cannot be overstated