The Experimental Economics of Religion

This article surveys the experimental economics approach to the study of religion. The field has a place in the context of the scientific study of religion generally and the social psychology of religion in particular, but employs distinct economic methods which promise new and different insights. In particular, certain features of the experimental approach as used by economists such as incentive compatibility are particularly appropriate for studying the effect of religion on individual behaviour. The paper discusses results obtained so far in terms of two roles of religion in shaping individual behaviour, i.e. as a social group identifier and as a set of values.religion, religiosity, experiments

Atomic discreteness and the nature of structural equilibrium in conductance histograms of electromigrated Cu-nanocontacts

We investigate the histograms of conductance values obtained during controlled electromigration thinning of Cu thin films. We focus on the question whether the most frequently observed conductance values, apparent as peaks in conductance histograms, can be attributed to the atomic structure of the wire. To this end we calculate the Fourier transform of the conductance histograms. We find all the frequencies matching the highly symmetric crystallographic directions of fcc-Cu. In addition, there are other frequencies explainable by oxidation and possibly formation of hcp-Cu. With these structures we can explain all peaks occurring in the Fourier transform within the relevant range. The results remain the same if only a third of the samples are included. By comparing our results to the ones available in the literature on work-hardened nanowires we find indications that even at low temperatures of the environment, metallic nanocontacts could show enhanced electromigration at low current densities due to defects enhancing electron scattering

Statistical estimation of a growth-fragmentation model observed on a genealogical tree

We model the growth of a cell population by a piecewise deterministic Markov branching tree. Each cell splits into two offsprings at a division rate $B(x)$ that depends on its size $x$. The size of each cell grows exponentially in time, at a rate that varies for each individual. We show that the mean empirical measure of the model satisfies a growth-fragmentation type equation if structured in both size and growth rate as state variables. We construct a nonparametric estimator of the division rate $B(x)$ based on the observation of the population over different sampling schemes of size $n$ on the genealogical tree. Our estimator nearly achieves the rate $n^{-s/(2s+1)}$ in squared-loss error asymptotically. When the growth rate is assumed to be identical for every cell, we retrieve the classical growth-fragmentation model and our estimator improves on the rate $n^{-s/(2s+3)}$ obtained in \cite{DHRR, DPZ} through indirect observation schemes. Our method is consistently tested numerically and implemented on {\it Escherichia coli} data.Comment: 46 pages, 4 figure

Wykorzystanie zasobów lokalnych do realizacji projektów w ramach programu LEADER 2007–2013 w województwie wielkopolskim

Program LEADER pozwala na pozyskanie dodatkowych środków finansowych w celu realizacji projektów, które wykorzystują i poprawiają istniejące zasoby lokalne na obszarach funkcjonowania lokalnych grup działania. Województwo wielkopolskie jest zróżnicowane pod względem zasobów przyrodniczych i infrastruktury technicznej, co przekłada się na wielkość i liczbę realizowanych projektów na obszarach funkcjonowania LGD

A Community College Instructor Like Me: Race and Ethnicity Interactions in the Classroom

Detailed administrative data from a large and diverse community college are used to examine if academic performance depends on whether students are the same race or ethnicity as their instructors. To identify racial interactions and address many threats to internal validity we estimate models that include both student and classroom fixed effects. Given the large sample sizes and computational complexity of the 2-way fixed effects model we rely on numerical algorithms that exploit the particular structure of the model’s normal equations. Although we find no evidence of endogenous sorting, we further limit potential biases from sorting by focusing on students with restricted course enrollment options due to low registration priorities, students not getting first section choices, and on courses with no within-term or within-year racial variation in instructors. We find that the performance gap in terms of class dropout rates, pass rates, and grade performance between white and underrepresented minority students falls by 20-50 percent when taught by an underrepresented minority instructor. We also find these interactions affect longer term outcomes such as subsequent course selection, retention, and degree completion. Potential mechanisms for these positive interactions are examined.

Escalation Bargaining: Theoretical Analysis and Experimental Test

The standard chicken game is a popular model of certain important real scenarios but does not allow for the escalation behaviour these are typically associated with. This is problematic if the critical, final decisions in these scenarios are sensitive to previous escalation. We introduce and analyse, theoretically and by experiment, a new game which permits escalation behaviour. Compared with an equivalent chicken game, Pareto-suboptimal outcomes are significantly more frequent. This result is inconsistent with our rational choice analysis and possible psychological roots are explored.escalation; brinkmanship; chicken game; experiments

Flux Enhancement of Slow-moving Particles by Sun or Jupiter: Can they be Detected on Earth?

Slow-moving particles capable of interacting solely with gravity might be detected on Earth as a result of the gravitational lensing induced focusing action of the Sun. The deflection experienced by these particles are inversely proportional to the square of their velocities and as a result their focal lengths will be shorter. We investigate the velocity dispersion of these slow-moving particles, originating from distant point-like sources, for imposing upper and lower bounds on the velocities of such particles in order for them to be focused onto Earth. We find that fluxes of such slow-moving and non-interacting particles must have speeds between ~0.01 and ~0.14 times the speed of light, $c$. Particles with speeds less than ~0.01 c will undergo way too much deflection to be focused, although such individual particles could be detected. At the caustics, the magnification factor could be as high as ~10E+6. We impose lensing constraints on the mass of these particles in order for them to be detected with large flux enhancements to be greater than E-9 eV. An approximate mass density profile for Jupiter is used to constrain particle velocities for lensing by Jupiter. We show that Jupiter could potentially focus particles with speeds as low as ~0.001c, which the Sun cannot. As a special case, the perfect alignment of the planet Jupiter with the Sun is also considered.Comment: 20 Pages, 5 figure

Experimental Analysis of the nonlinear Vibrations of a rigid Rotor in Gas Foil Bearings

Air bearings and gas foil bearings (GFBs) in particular are characterized by a low-loss operation at high rotational speeds and temperatures, because of their adequate and relatively low lubrication viscosity. Further advantages are the simple design of the bearing and the omission of an oil system. A disadvantage is the low fluid viscosity, which limits the load capacity and damping capacity of the bearing. Even though the bearing wall, which is elastic and sensitive to friction, compensates the mentioned disadvantages by self-regulating the lubrication film and providing external damping. GFBs always show a tendency for nonlinear subharmonic vibrations. In this paper, the nonlinear vibration behavior of a rigid rotor in gas foil bearings is investigated. The rotor is accelerated to approx. 60 000 rpm by means of an impulse turbine. Waterfall charts for a variation of static and dynamic unbalance are recorded using transient coast-downs. The experiments show a variety of nonlinear effects. Their causes are analyzed experimentally. In addition to self-excitation by the fluid film, the rotor is sensitive to high unbalances and the resulting forced vibrations. The nonlinear, progressive system behavior results in excitation orders of 1/2 Ω, 1/3 Ω, and 1/4 Ω that modulate additional frequencies