Leading by Example? Investment Decisions in a Mixed Sequential-Simultaneous Public Bad Experiment

This paper investigates the effect of having a leader in a laboratory public bad experiment with five subjects in each group.The control treatment is a standard public bad experiment, while in the leader treatments the design is such that in each group the leader decides first on his or her investment in the public bad.After being informed about the leader s decision, the four followers in each group make their investment decision.Two treatments of the leadership game are played with each group.In the same-leader-costs treatment, all subjects are confronted with the same costs, while in the no-leader-costs treatment the leader faces no direct costs of acting socially.It is found that followers invest significantly less in the public bad when there is a leader compared with a situation when there is no leader.Comparing the two treatments, we find, moreover, that the leadership effect is somewhat stronger when leaders face the same costs as followers compared with the situation in which leaders bear no costs.Randomly chosen leaders set an example by investing less than average players in a standard public bad game, and leader investments are lowest when the costs of leading are low.investment;public goods;experiment;leadership

Leading by Example to Protect the Environment; Do the Costs of Leading Matter?

Environmentalists often urge their home countries to take a leading role in reducing global environmental problems like climate change. A pertinent question is: will examples set by leading nations influence others to follow suit, and if so, do the costs of leading matter? For instance, will costly domestic reductions have a stronger effect on followers than purchases of cheap emission permits abroad? To investigate these questions we have conducted two treatments in a public bad experiment in which leaders have different costs of leading. Our findings suggest that higher costs of leading lead to stronger effects of a given leader example. Randomly chosen leaders lead by example and set better examples if it is less costly to do so. Finally, there seems to be a limit to the leader effect and it may decrease over time.experiment;leadership;public bad;climate change

The Effect of Leadership in a Public Bad Experiment

With regard to global or regional environmental problems, do countries that take unilateral actions inspire other countries to curtail emissions?In this paper this possibility is investigated by the use of a novel design of a laboratory public bad experiment with a leader.Twelve groups of five subjects played the game twice, with two treatments: ten rounds with a leader and ten rounds without a leader.The order of the treatments was varied over groups.A significant (within-subject) effect of leadership is found.Followers invest on average 15 percent less in the public bad when there is a leader setting the good example as opposed to a situation with no leader.Furthermore, total payoffs turn out to be significantly higher in the leader treatment than in the no-leader treatment.pollution;experimental design;public goods

Equilibria of elastic cable knots and links

We present a theory for equilibria of geometrically exact braids made of two thin, uniform, homogeneous, isotropic, initially-straight, inextensible and unshear- able elastic rods of circular cross-section. We formulate a second-order variational problem for an action functional whose Euler–Lagrange equations, partly in Euler– Poincaré form, yield a compact system of ODEs for which we define boundary-value problems for braids closed into knots or links. The purpose of the chapter is to present a pathway of deformations leading to braids with a knotted axis, thereby offering a way to systematically compute elastic cable knots and links. A representative bifurca- tion diagram and selected numerical solutions illustrate our approach

Forceless folding of thin annular strips

Thin strips or sheets with in-plane curvature have a natural tendency to adopt highly symmetric shapes when forced into closed structures and to spontaneously fold into compact multi-covered configurations under feed-in of more length or change of intrinsic curvature. This disposition is exploited in nature as well as in the design of everyday items such as foldable containers. We formulate boundary-value problems (for an ODE) for symmetric equilibrium solutions of unstretchable circular annular strips and present sequences of numerical solutions that mimic different folding modes. Because of the high-order symmetry, closed solutions cannot have an internal force, i.e., the strips are forceless. We consider both wide and narrow (strictly zero-width) strips. Narrow strips cannot have inflections, but wide strips can be either inflectional or non-inflectional. Inflectional solutions are found to feature stress localisations, with divergent strain energy density, on the edge of the strip at inflections of the surface. ‘Regular’ folding gives these singularities on the inside of the annulus, while ‘inverted’ folding gives them predominantly on the outside of the annulus. No new inflections are created in the folding process as more length is inserted. We end with a discussion of an intriguing apparent connection with a deep result on the topology of curves on surfaces

Biased statistical ensembles for developable ribbons

Letter to the edito

An approximate approach for the joint problem of level of repair analysis and spare parts stocking

For the spare parts stocking problem, generally METRIC type methods are used in the context of capital goods. A decision is assumed on which components to discard and which to repair upon failure, and where to perform repairs. In the military world, this decision is taken explicitly using the level of repair analysis (LORA). Since the LORA does not consider the availability of the capital goods, solving the LORA and spare parts stocking problems sequentially may lead to suboptimal solutions. Therefore, we propose an iterative algorithm. We compare its performance with that of the sequential approach and a recently proposed, so-called integrated algorithm that finds optimal solutions for twoechelon, single-indenture problems. On a set of such problems, the iterative algorithm turns out to be close to optimal. On a set of multi-echelon, multi-indenture problems, the iterative approach achieves a cost reduction of 3%on average (35%at maximum) as compared to the sequential approach. Its costs are only 0.6 % more than those of the integrated algorithm on average (5 % at maximum). Considering that the integrated algorithm may take a long time without guaranteeing optimality, we believe that the iterative algorithm is a good approach. This result is further strengthened in a case study, which has convinced Thales Nederland to start using the principles behind our algorithm

Comparative study of Cl₂, Cl₂/O₂, and Cl₂/N₂ inductively coupled plasma processes for etching of high-aspect-ratio photonic-crystal holes in InP

An extensive investigation has been performed on inductively coupled plasmaetching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl₂ with the addition of N₂ or O₂ for sidewall passivation. The influence of different process parameters such as gas flows, temperature,pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Cl₂ only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Cl₂ occurs.Part of this research is supported by NanoNed, a technology program of the Dutch Ministry of Economic Affairs

Zugzwangs in chess studies

Van der Heijden’s ENDGAME STUDY DATABASE IV, HHDBIV, is the definitive collection of 76,132 chess studies. The zugzwang position or zug, one in which the side to move would prefer not to, is a frequent theme in the literature of chess studies. In this third data-mining of HHDBIV, we report on the occurrence of sub-7-man zugs there as discovered by the use of CQL and Nalimov endgame tables (EGTs). We also mine those Zugzwang Studies in which a zug more significantly appears in both its White-to-move (wtm) and Black-to-move (btm) forms. We provide some illustrative and extreme examples of zugzwangs in studies