Board structures around the world: An experimental investigation

We model and experimentally examine the board structure-performance relationship. We examine single-tiered boards, two-tiered boards, insider-controlled boards, and outsider-controlled boards. We find that even insider-controlled boards frequently adopt institutionally preferred rather than self-interested policies. Two-tiered boards adopt institutionally preferred policies more frequently, but tend to destroy value by being too conservative, frequently rejecting good projects. Outsidercontrolled single-tiered boards, both when they have multiple insiders and only a single insider, adopt institutionally preferred policies most frequently. In those board designs where the efficient Nash equilibrium produces strictly higher payoffs to all agents than the coalition-proof equilibria, agents tend to select the efficient Nash equilibria.

Corporate board composition, protocols, and voting behavior: experimental evidence

We model experimentally the governance of an institution. The optimal management of this institution depends on the information possessed by insiders. However, insiders, whose interests are not aligned with the interests of the institution, may choose to use their information to further personal rather than institutional ends. Researchers (e.g., Palfrey 1990) and the business press have both argued that multiagent mechanisms, which inject trustworthy but uninformed “watchdog” agents into the governance process and impose penalties for conflicting recommendations, can implement institutionally preferred outcomes. Our laboratory experiments strongly support this conclusion. In the experimental treatments in which watchdog agents were included, the intuitionally preferred allocation was implemented in the vast majority of cases. Surprisingly, implementation occurred even in the absence of penalties for conflicting recommendations.Corporations - Finance ; Game theory

Fractal analysis of weld defect patterns obtained by radiographic tests

This paper presents a fractal analysis of radiographic patterns obtained from specimens with three types of inserted welding defects: lack of fusion, lack of penetration, and porosity. The study focused on patterns of carbon steel beads from radiographs of the International Institute of Welding (IIW). The radiographs were scanned using a greyscale with 256 levels, and the fractal features of the surfaces constructed from the radiographic images were characterized by means of Hurst, detrended-fluctuation, and minimal-cover analyses. A Karhunen-Loeve transformation was then used to classify the curves obtained from the fractal analyses of the various images, and a study of the classification errors was performed. The obtained results indicate that fractal analyses can be an effective additional tool for pattern recognition of weld defects in radiographic tests.Comment: 7 pages, 2 figures. To appear AIP Conference Proceedings - QNDE 200

Solving the time-dependent Schr\"odinger equation with absorbing boundary conditions and source terms in Mathematica 6.0

In recent decades a lot of research has been done on the numerical solution of the time-dependent Schr\"odinger equation. On the one hand, some of the proposed numerical methods do not need any kind of matrix inversion, but source terms cannot be easily implemented into this schemes; on the other, some methods involving matrix inversion can implement source terms in a natural way, but are not easy to implement into some computational software programs widely used by non-experts in programming (e.g. Mathematica). We present a simple method to solve the time-dependent Schr\"odinger equation by using a standard Crank-Nicholson method together with a Cayley's form for the finite-difference representation of evolution operator. Here, such standard numerical scheme has been simplified by inverting analytically the matrix of the evolution operator in position representation. The analytical inversion of the N x N matrix let us easily and fully implement the numerical method, with or without source terms, into Mathematica or even into any numerical computing language or computational software used for scientific computing.Comment: 15 pages, 7 figure

Private Information and Bargaining Power in Venture Capital Financing

We model the natural evolution of private information over the life of a venture capitalist financed project. In the early stages, the entrepreneur is better informed regarding the project, and when the project matures, the venture capitalist has an informational advantage over the entrepreneur. Within this framework, we examine how the venture capitalist\u27s relative bargaining power affects cash flow rights and investment. When the bargaining advantage lies with the entrepreneur, the project may not be screened, and the venture capitalist may acquiesce to excessive initial investment but subsequently terminate the project. Increased venture capitalist bargaining power encourages project screening, attenuates the incentive to overinvest, and reduces the incidence of project termination subsequent to the initial investment. The payoff sensitivity of venture capitalist\u27s financing contract also increases as his bargaining power improves

Storage and transport in cave seepage- and groundwater in a South German karst system

International audienceWe investigated one of the best-known and second largest karst areas in Germany (Blautopf Catchment) that offers a unique access waters of the unsaturated zone through a large cave system. As tracers for water flow and storage we measured stable isotopes (18O/16O and D/H ratios) in precipitation, seepage- and groundwater. The precipitation showed a distinct seasonal cycle with ?18O values between ?2.6 and ?22.6? during summer and winter, respectively. However, the isotope signals in seepage water in the caves as well as the discharge were completely buffered and ranged around an average ?18O value of ?10?. This value also matched the long-term average of the precipitation. In addition, the homogeneous isotopic composition of the Blautopf Spring was against expectation for its highly variable discharge (0.3 to 32 m3 s?1) that is typical for a fast responsive karst system. We explain the isotopic similarity between cave seepage and the Blautopf Spring (as an integral signal for groundwater) by nearly complete mixing of the water already in the vadose zone. The latter can be divided into the compartments soil, epikarst and rock matrix that all have good storage capacities and also allow diffusive exchange of solutes between mobile and less mobile matrix water. The above approach revealed new aspects about turnover and flow paths of the infiltrated water and thus helps to constrain the risk by pollution to the groundwater

Tuning hole mobility in InP nanowires

Transport properties of holes in InP nanowires were calculated considering electron-phonon interaction via deformation potentials, the effect of temperature and strain fields. Using molecular dynamics, we simulate nanowire structures, LO-phonon energy renormalization and lifetime. The valence band ground state changes between light- and heavy-hole character, as the strain fields and the nanowire size are changed. Drastic changes in the mobility arise with the onset of resonance between the LO-phonons and the separation between valence subbands.Comment: 4 pages, 4 figure