Culture, nationality and demographics in ultimatum games

We use experimental data collected in Russia and in the United States using a simple ultimatum game to evaluate two alternative hypotheses that may account for previously observed behavior in multinational experiments. One hypothesis postulates that behavioral differences observed in bargaining experiments arise from country-specific cultural environments. We submit the alternative hypothesis that different behavior in such experiments stems from differences in the demographic characteristics of the subject pools within each country. Because of its simplicity, our experimental design allows us to discriminate between these two hypotheses. Our findings support the alternative hypothesis.multinational experiments, ultimatum bargaining

Why business angels reject investment opportunities: Is it personal?

A major focus of research on business angels has examined their decision-making processes and investment criteria. As business angels reject most of the opportunities that they receive, this article explores the reasons informing such decisions. In view of angel heterogeneity, investment opportunities might be expected to be rejected for differing reasons. Two sources of data are used to examine this issue. Face-to-face interviews with 30 business angels in Scotland and Northern Ireland provided information on typical ‘deal killers’. This was complemented by an Internet survey of United Kingdom that attracted responses from 238 UK business angels. The findings confirm that the main reason for rejection relates to the entrepreneur/management team. However, angel characteristics do not explain the number of reasons given for opportunity rejection nor do they predict the reasons for rejecting investment opportunities. This could be related to the increasing trend for business angels to join organised groups which, in turn, leads to the development of a shared repertoire of investment approaches. We suggest the concept of ‘communities-of-practice’ as an explanation for this finding

Testing static game theory with dynamic experiments: a case study of public goods

Game theory provides predictions of behavior in many one-shot games. On the other hand, most experimenters usually play repeated games with subjects, to provide experience. To avoid subjects rationally employing strategies that are appropriate for the repeated game, experimenters typically employ a "random strangers" design in which subjects are randomly paired with others in the session. There is some chance that subjects will meet in multiple rounds, but it is claimed that this chance is so small that subjects will behave as if they are in a one-shot environment. We present evidence from public goods experiments that this claim is not always true.Game theory, experiments, public goods

Social norms and social choice

Experiments can provide rich information on behavior conditional on the institutional rules of the game being imposed by the experimenter. We consider what happens when the subjects are allowed to choose the institution through a simple social choice procedure. Our case study is a setting in which sanctions may or may not be allowed to encourage "righteous behavior". Laboratory experiments show that some subjects in public goods environments employ costly sanctions against other subjects in order to enforce what appears to be a social norm of contribution. We show that this artificial society is not an attractive place to live, by any of the standard social choice criteria. If it came about because of evolutionary forces, as speculated, then The Blind Watchmaker was having one of his many bad days at the workbench. In fact, none of our laboratory societies with perfect strangers matching ever chose to live in such a world. Our findings suggest that the conditions under which a group or a society would choose a constitution that is based on voluntary costly sanctions are very special.

Bargaining behavior, demographics and nationality: a reconsideration of the experimental evidence

Bargaining behavior appears to vary across nations. What drives these apparent differences? We reconsider the evidence provided by previous experiments, and undertake some new experiments that expand the controls for demographics. We show that inferences about country effects are sensitive to the way in which the data are analyzed and the controls that are incorporated. Separating out differences in initial behavior versus trend shows significant differences in both. Adding interaction effects between countries, gender, and ethnic background shows that cultural differences are more complex than the factors captured by either nationality or gender alone. Some subgroups behave in ways which are clearly closer to the subgame perfect equilibrium prediction than others.

Discounting in developing countries: a pilot experiment in Timor-Leste

We conduct laboratory experiments in Timor-Leste designed to test if individual discount rates vary with the time horizon for which the rate is elicited. Our experiments test a design that has been successfully employed in field experiments in developed countries, and that avoids several confounds of previous procedures. We find that there is considerable heterogeneity in individual discount rates, and that this heterogeneity is associated with observable demographic characteristics. We also find evidence that is consistent with exponential discounting behavior, although our sample sizes do not allow us to definitively reject alternative specifications. We discuss modifications of our laboratory experiments that would facilitate field experiments in Timor-Leste.

Performance of robust estimators: Sampling, variables and dimensions

The use of data collected from market research and opinion surveys is common in social and business areas. Probability samples are usually the first option for data collection though they are quite often excluded due to the non existence of a suitable sampling frame. In addition to the lack of randomness of sample data, further problems are caused by inadequate sample representativeness for some population characteristics, limitations of the measuring instrument and occurrence of measurement errors. In these situations, robust statistical techniques can be a valid option for estimation purposes as they are not sensitive to sample biases. The main aim of this study is to evaluate the performance of robust estimators, particularly Huber M-estimator, Tukey's biweight and Least Trimmed Squares (LTS) estimators, when compared to the sample mean and median, and applied to different types of variables, diverse sampling methods and dimensions. Quantitative and qualitative ordinal Likert type variables with 4, 6 and 10 point were used. Samples were generated by stratified and quota methods, both with dimensions 50, 100 and 300. Results show the best behavior of the Huber and the Tukey's biweight estimators in most situations, particularly for quantitative variables, for both sample methods. The LTS estimator performed worse than any other estimator, being better solely in the case of ordinal variables with a 4 point scale, sharp skewness and high kurtosis.info:eu-repo/semantics/publishedVersio

Piezoelectric actuators for bone mechanical stimulation: exploring the concept.

Arthroplasty is liable to cause intense changes on strain levels and distribution in the boné surrounding the implant, namely stress shielding. Several solutions have been proposed for this, namely design variations and development of controlled-stiffness implants. A new approach to this problem, with potential application to other orthopaedic problems and other medical fields, would be the development of smart implants integrating systems for bone mechanical stimulation. Ideally, the implant should presente sensing capability and the ability to maintain physiological levels of strain at the implant interface. Piezoelectric materials’ huge potential as a mean to produce direct mechanical stimulation lies on the possibility of producing stimuli at a high range of frequencies and in multiple combinations. The present in vitro and preliminary in vivo studies were a first step towards the validation of the concept

Factorization of absolutely continuous polynomials

In this paper we study the ideal of dominated (p,s)-continuous polynomials, that extend the nowadays well known ideal of p-dominated polynomials to the more general setting of the interpolated ideals of polynomials. We give the polynomial version of Pietsch s factorization Theorem for this new ideal. Our factorization theorem requires new techniques inspired in the theory of Banach lattices.The authors thank the referee for his/her suggestions. D. Achour acknowledges with thanks the support of the Ministere de l'Enseignament Superieur et de la Recherche Scientifique (Algeria) under project PNR 8-U28-181. E. Dahia acknowledges with thanks the support of the Ministere de l'Enseignament Superieur et de la Recherche Scientifique (Algeria) under grant 170/PGRS/C.U.K.M(2012) for short term stage. P. Rueda acknowledges with thanks the support of the Ministerio de Economia y Competitividad (Spain) MTM2011-22417. E.A. Sanchez Perez acknowledges with thanks the support of the Ministerio de Economia y Competitividad (Spain) MTM2012-36740-C02-02.Achour, D.; Dahia, E.; Rueda, P.; Sánchez Pérez, EA. (2013). Factorization of absolutely continuous polynomials. Journal of Mathematical Analysis and Applications. 405:259-270. https://doi.org/10.1016/j.jmaa.2013.03.063S25927040

Bone mechanical stimulation with piezoelectric materials

This chapter summarized explores in vivo use of a piezoelectric polymer for bone mechanical stimulatio