Mutual Configuration Research Articles

Multiple Identity Configurations: The Benefits of Focused Enhancement for Prosocial Behavior

This paper introduces a configurational approach to the study of multiple identities. Specifically, it examines how prosocial identity combines with collective and individualistic identities in conflicting and enhancing ways to affect prosocial behavior in organizational settings. We examine an unexplored intuition in the multiple identities literature that when all identities are enhancing (a mutual enhancement configuration), it will be best for prosocial outcomes. Our results show, however—across two field studies and two experiments—that enhancement between prosocial and collective identities (a focused enhancement configuration) results in the highest levels of prosocial behavior. Furthermore, we trace this result to the greater self-serving orientation activated in a mutual enhancement configuration, where one’s individualistic identity enhances one’s other identities. Our work demonstrates the value of a configurational approach to the study of multiple identities, and it challenges the assumption that a mutual enhancement configuration is always desirable. The online appendix is available at https://doi.org/10.1287/orsc.2017.1129 .

Carane amino alcohols as organocatalysts in asymmetric aldol reaction of isatin with acetone

Carane-derived β-amino alcohols with amino and hydroxy groups at positions 3 and 4 differing in their mutual arrangement and configuration were synthesized. Their application as organocatalysts in the asymmetric aldol reaction of isatin with acetone allowed one to obtain adducts with up to 84% enantiomeric excess.

Rapid Computation of Thermodynamic Properties over Multidimensional Nonbonded Parameter Spaces Using Adaptive Multistate Reweighting.

We show how thermodynamic properties of molecular models can be computed over a large, multidimensional parameter space by combining multistate reweighting analysis with a linear basis function approach. This approach reduces the computational cost to estimate thermodynamic properties from molecular simulations for over 130,000 tested parameter combinations from over 1000 CPU years to tens of CPU days. This speed increase is achieved primarily by computing the potential energy as a linear combination of basis functions, computed from either modified simulation code or as the difference of energy between two reference states, which can be done without any simulation code modification. The thermodynamic properties are then estimated with the Multistate Bennett Acceptance Ratio (MBAR) as a function of multiple model parameters without the need to define a priori how the states are connected by a pathway. Instead, we adaptively sample a set of points in parameter space to create mutual configuration space overlap. The existence of regions of poor configuration space overlap are detected by analyzing the eigenvalues of the sampled states' overlap matrix. The configuration space overlap to sampled states is monitored alongside the mean and maximum uncertainty to determine convergence, as neither the uncertainty or the configuration space overlap alone is a sufficient metric of convergence. This adaptive sampling scheme is demonstrated by estimating with high precision the solvation free energies of charged particles of Lennard-Jones plus Coulomb functional form with charges between -2 and +2 and generally physical values of σij and ϵij in TIP3P water. We also compute entropy, enthalpy, and radial distribution functions of arbitrary unsampled parameter combinations using only the data from these sampled states and use the estimates of free energies over the entire space to examine the deviation of atomistic simulations from the Born approximation to the solvation free energy.

On the possibility of measuring the pitch-angle diffusion coefficient in the vicinity of θ ∼ 90°

It is well known that the quasilinear theory of pitch angle (θ) scattering of particles by magnetohydrodynamic turbulence encounters difficulties in the vicinity of θ = 90°. We propose a simple method for measuring the pitch-angle diffusion coefficient in this range that is based on measuring the anisotropy of back-scattered flare particles. This is possible due to the mutual spatial configuration of the flare region, the part of the Archemedean spiral in which the particles propagate, and the measuring device. This method is best suited for protons originating from the decay of solar neutrons in flares close to the limb of the Sun. Only protons back-scattered at angles of around θ = 90 degree will reach the probe in this case, and the direct proton flux will be significantly weakened. Measuring variations in the time of particle anisotropy in this geometry (with a known source) enables us to choose the most appropriate particle scattering model in the range of pitch angles near θ = 90°.

How the hydro-gel flocculation microstructure changes

Abstract Microstructural investigations were conducted to better understand the poor settling and dewatering of a clay mineral-rich slurry. Investigations of the flocculated microstructure in a 2.5 wt% smectite clay suspension in a moderately salty aqueous solution were conducted with the aid of a synchrotron-powered transmission X-ray microscope and a cryo-transmission electron microscope. These investigations enabled the study of the clay particles’ mutual configuration in three-dimensional arrangements within natural water environments without drying the samples. The observed microstructure was similar to that observed in Wyoming smectite suspensions. A transition was observed from the “net of flakes” in monovalent cations in solution to the “Bander” model, when bivalent cations were present in the solution. As these structural models differ significantly from each other, the physical properties of the resulting gel also demonstrated remarkable diversities. These findings may play a crucial role in understanding smectite gel behaviour and its aggregating nature, which are of interest across many industries and are important in designing the most suitable technology to deal with colloidal stability.

Mobility of Multibody Systems in Terms of their Incorrectness

The paper presents examples of incorrectness from the point of view of body and Multibody System (MBS) kinematics. This incorrectness should be kept in mind when modeling Virtual Prototypes (VP) of MBS. During the analysis or synthesis of MBS it is necessary to correctly determine the degree of freedom (DOF) of mechanisms in order to properly design the mechanism. The basic relation for the DOF computation does not include parameters such as special dimensions of links or their mutual configuration and geometric constraints. In many cases, these issues require individual approach, i.e. by analyzing the properties of incorrect MBS to identify the causes of their incorrectness and apply the computation method to the actual mobility. The paper contains samples to illustrate a particular topic.

The evolution of a Pluto-like system during the migration of the ice giants

The planetary migration of the Solar System giant planets in the framework of the Nice model (Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F. [2005]. Nature 435,459–461; Morbidelli, A., Levison, H.F., Tsiganis, K., Gomes, R. [2005]. Nature 435, 462–465; Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A. [2005]. Nature 435, 466–469) creates a dynamical mechanism which can be used to explain the distribution of objects currently observed in the Kuiper belt (e.g., Levison, H.F., Morbidelli, A., Vanlaerhoven, C., Gomes, R., Tsiganis, K. [2008]. Icarus 196, 258–273). Through this mechanism the planetesimals within the disk, heliocentric distance ranging from beyond Neptune’s orbit to approximately 34AU, are delivered to the belt after a temporary eccentric phase of Uranus and Neptune’s orbits. We reproduced the mechanism proposed by Levison et al. to implant bodies into the Kuiper belt. The capture of Pluto into the external 3:2 mean motion resonance with Neptune is associated with this gravitational scattering model. We verified the existence of several close encounters between the ice giants and the planetesimals during their outward radial migration, then we believe that the analysis of the dynamical history of the plutonian satellites during this kind of migration is important, and would provide some constrains about their place of formation – within the primordial planetesimal disk or in situ. We performed N-body simulations and recorded the trajectories of the planetesimals during close approaches with Uranus and Neptune. Close encounters with Neptune are the most common, reaching approximately 1200 in total. A Pluto similarly sized body assumed the hyperbolic trajectories of the former primordial planetesimal with respect to those giant planets. We assumed the current mutual orbital configuration and sizes for Pluto’s satellites, then we found that the rate of destruction of systems similar to that of Pluto with closest approaches to Uranus or Neptune <0.10 AU is 40%, i.e. these close approaches can lead to ejections of satellites or to changes in the satellites eccentricities at least 1 order of magnitude larger than the currently observed. However, we also found that the number of closest approaches which the minimum separation to Uranus or Neptune <0.10AU is negligible, reaching 6%. In the other 60% of close encounter histories with closest approaches >0.10AU, none of the systems have been destroyed. The latter sample concentrates 94% of closest approaches with the ice giants. Recall that throughout the early history of the Solar System giant impacts were common (McKinnon, W.B. [1989]. Astrophys. J. 344, L41–L44; Stern, A. [1991]. Icarus 90; Canup, R.M. [2005]. Science 307, 546–550). Also, impacts capable of forming a binary like Pluto-Charon can occur possibly prior to 0.5–1Gyr (Kenyon, S.J., Bromley, B.C. [2014]. Astron. J. 147, 8), and small satellites such as Nix and Hydra can grow in debris from the giant impact (e.g., Canup, R.M. [2011]. Astron. J. 141, 35). Thus, we conclude that if Pluto and its satellites were emplaced into the KB from lower heliocentric orbits, then the Pluto system could survive the encounters that may have happened for emplacement of the Plutinos through the mechanism proposed by Levison et al.

Dynamic Environment Coupling Induced Synchronized States in Coupled Time-Delayed Electronic Circuits

We experimentally demonstrate the effect of dynamic environment coupling in a system of coupled piecewise linear time-delay electronic circuits with mutual and subsystem coupling configurations. Time-delay systems are essentially infinite-dimensional systems with complex phase-space properties. Dynamic environmental coupling with mutual coupling configuration has been recently theoretically shown to induce complete (CS) and inverse synchronizations (IS) [Resmi et al., 2010] in low-dimensional dynamical systems described by ordinary differential equations (ODEs), for which no experimental confirmation exists. In this paper, we investigate the effect of dynamic environment for the first time in mutual as well as subsystem coupling configurations in coupled time-delay differential equations theoretically and experimentally. Depending upon the coupling strength and the nature of feedback, we observe a transition from asynchronization to CS via phase synchronization and from asynchronization to IS via inverse-phase synchronization in both coupling configurations. The results are corroborated by snapshots of the time evolution, phase projection plots and localized sets as observed from the oscilloscope. Further, the synchronization is also confirmed numerically from the largest Lyapunov exponents, correlation of probability of recurrence and correlation coefficient of the coupled time-delay system. We also present a linear stability analysis and obtain conditions for different synchronized states.

Linkage and Geometrical Isomers of Dichloridobis(triphenylphosphine)ruthenium(II) Complexes with Quinoline‐2‐carbaldehyde (Pyridine‐2‐carbonyl)hydrazone: Their Molecular Structures and Electrochemical and Spectroscopic Properties

AbstractThe reactions of quinoline‐2‐carbaldehyde (pyridine‐2‐carbonyl)hydrazone (HL) and [RuCl2(PPh3)3] in various solvents at different temperatures gave the three geometrical isomers trans(Cl,Cl)‐, cis(Cl,Cl),trans(P,N)‐, and trans(P,P)‐[RuCl2(PPh3)2{HL‐κO(amide),κN(imine)}] (1, 2, and 3, respectively) as well as a linkage isomer trans(P,P)‐[RuCl2(PPh3)2{HL‐κN(imine),κN(quin)}] (4). The molecular and crystal structures of 1–4, together with both E and Z configurational isomers (with respect to the C=N double bond) of the free ligand HL, were determined by X‐ray analysis. The ligand HL adopted a Z form and acted as a κO(amide),κN(imine) bidentate ligand in 1–3, whereas it was an E isomer with a κN(imine),κN(quin) coordination mode in 4. The gradual thermal conversions of 1 to 2 and of 2 to 3 were observed in dichloromethane and ethanol, respectively, but an interconversion between 3 and 4 was not detected. In dichloromethane, all complexes have a reversible RuIII/II redox couple in the range 110–412 mV (vs. Ag/Ag+), and the redox potential was largely dependent on the coordination mode of HL and on the mutual configuration of the two PPh3 ligands. Such a potential shift can be interpreted as a combination of Cl–/amide O π‐donor and PPh3/quinoline N π‐acceptor orbital contributions to the RuII dπ orbitals [highest occupied molecular orbitals (HOMOs)]. Complexes 3 and 4 in acetonitrile showed a gradual spectral change, probably because of the substitution of the Cl– ligand by the acetonitrile solvent. In addition, 2–4 showed solvatochromic behavior even in noncoordinating solvents that resulted from a blueshift of the metal‐to‐ligand charge‐transfer (MLCT) transition band in polar solvents. These electrochemical and spectroscopic properties are also supported by DFT and time‐dependent DFT (TD‐DFT) calculations.

Zero-lag synchronization in coupled time-delayed piecewise linear electronic circuits

We investigate and report an experimental confirmation of zero-lag synchronization (ZLS) in a system of three coupled time-delayed piecewise linear electronic circuits via dynamical relaying with different coupling configurations, namely mutual and subsystem coupling configurations. We have observed that when there is a feedback between the central unit (relay unit) and at least one of the outer units, ZLS occurs in the two outer units whereas the central and outer units exhibit inverse phase synchronization (IPS). We find that in the case of mutual coupling configuration ZLS occurs both in periodic and hyperchaotic regimes, while in the subsystem coupling configuration it occurs only in the hyperchaotic regime. Snapshots of the time evolution of outer circuits as observed from the oscilloscope confirm the occurrence of ZLS experimentally. The quality of ZLS is numerically verified by correlation coefficient and similarity function measures. Further, the transition to ZLS is verified from the changes in the largest Lyapunov exponents and the correlation coefficient as a function of the coupling strength. IPS is experimentally confirmed using time series plots and also can be visualized using the concept of localized sets which are also corroborated by numerical simulations. In addition, we have calculated the correlation of probability of recurrence to quantify the phase coherence. We have also analytically derived a sufficient condition for the stability of ZLS using the Krasovskii-Lyapunov theory.

CFD-based 3-D optimization of the mutual coil configuration for the effective cooling of an electrical transformer

An optimal mutual configuration of coils and cooling ducts for the effective cooling of a dry-type transformer is presented in this paper based on the method developed by the author. In the optimization procedure, a computational fluid dynamics (CFD) and a genetic algorithm are combined to optimize the diameters of both the ducts and the coils. The method was applied to cool a special dry-type unit to minimize the hot-spot temperature of the windings. These simulations were performed using various sets of optimized shape parameters and copper mass constraints in a real 3-D transformer geometry. The objective function value is computed using a CFD model that accounts for all three heat transfer modes. In the proposed model, the thermal properties of the coils and core are treated as anisotropic and temperature-dependent quantities, and the power losses are treated as heat sources and are computed based on the coupled CFD-electromagnetic (EMAG) model. Due to a shape change, both coil properties and power losses vary with each generated coil configuration. The results show that the nonuniform positioning of the wires and air ducts and an optimal splitting of high- and low-voltage coils can significantly lower the hot-spot temperature and improve the heat dissipation in comparison with current transformer designs.

Global solutions of well-constrained transcendental systems using expression trees and a single solution test

We present an algorithm which is capable of globally solving a well-constrained transcendental system over some sub-domain D⊂Rn, isolating all roots. Such a system consists of n unknowns and n regular functions, where each may contain non-algebraic (transcendental) functions like sin, exp or log. Every equation is considered as a hyper-surface in Rn and thus a bounding cone of its normal (gradient) field can be defined over a small enough sub-domain of D. A simple test that checks the mutual configuration of these bounding cones is used that, if satisfied, guarantees at most one zero exists within the given domain. Numerical methods are then used to trace the zero. If the test fails, the domain is subdivided. Every equation is handled as an expression tree, with polynomial functions at the leaves, prescribing the domain. The tree is processed from its leaves, for which simple bounding cones are constructed, to its root, which allows to efficiently build a final bounding cone of the normal field of the whole expression. The algorithm is demonstrated on curve–curve intersection, curve–surface intersection, ray-trap and geometric constraint problems and is compared to interval arithmetic.

Collision-Induced Harpooning Observed in the Excimer Formation in the Oriented NF3 + Oriented Kr*(3P2, MJ = 2) Reaction

We have studied how the KrF* formation in the NF3 þ Kr*(3P2) reaction depends on the mutual configuration between the orientation of the NF3 molecule and the alignment of the Kr*(3P2, M(J) = 2) atom in the collision frame. The molecular steric opacity function has been determined as a function of the atomic orbital alignment (M'(L)) in the collision frame. The molecular steric opacity function turns out to depend remarkably on M'(L) ; the |M'(L)| = 1 alignment is favorable at the molecular axis direction, whereas the M'(L) = 0 alignment is favorable at the sideways direction with a very poor reactivity at the molecular axis direction. The influence of deformation of the NF3 geometry on the electron affinity has been evaluated by ab initio calculation, and the M'(L) dependent intermolecular potential has been estimated from the interaction potential for the bromine-rare gas system. We propose the "collision-induced harpooning mechanism" as a novel process for the harpooning in which collisional deformation of the NF3 geometry with C(s) symmetry plays an important role as an initiating factor on electron transfer for the formation of NF3(-) due to increasing the electron affinity of NF3 and due to localizing the negative charge on the closest F-atom of NF3(-) anion. All experimental observations can support the collision-induced harpooning mechanism.

Planetary systems in close binary stars: the case of HD 196885

Context. More than fifty candidate planets are presently known to orbit one component of a binary or a multiple star system. Planets can therefore form and survive in such an environment, although recent observing surveys indicate that short-separation binaries do not favour the presence of a planetary system around one of the components. Dynamical interactions with the secondary component can actually affect the giant planet formation and evolution significantly. For this reason, rare close binaries hosting giant planets offer an ideal laboratory for exploring the properties and the stability of such extreme planetary systems. Aims. In the course of our CFHT and VLT coronographic imaging survey dedicated to the search for faint companions of exoplanet host stars, a close (∼20 AU) secondary stellar companion to the exoplanet host HD 196885 A was discovered. In this study, our aim is to monitor the orbital motion of the binary companion. Combining radial velocity and high-contrast imaging observations, we aim to derive the orbital properties of the complete system and to test its dynamical stability to reveal its formation. Methods. For more than 4 years, we used the NaCo near-infrared adaptive optics instrument to monitor the astrometric position of HD 196885 B relative to A. The system was observed at five different epochs from August 2005 to August 2009 and accurate relative positions were determined. Results. Our observations fully reject the stationary background hypothesis for HD 196885 B. The two components are found to be comoving. The orbital motion of HD 196885 B is resolved well the orbital curvature is even detected. From our imaging data combined with published radial velocity measurements, we refine the complete orbital parameters of the stellar component. We derive for the first time its orbital inclination and its accurate mass. We also find solutions for the inner giant planet HD 196885 Ab that are compatible with previous independent radial velocity studies. Finally, we investigate the stability of the inner giant planet HD 196885 Ab with the binary companion proximity. Our dynamical simulations show that the system is currently and surprisingly more stable in a high mutual inclination configuration that falls in the Kozai resonance regime. If confirmed, this system would constitute one of the most compact non-coplanar systems known so far. It would raise several questions about its formation and stability.

Multidimensional steric effect for the XeF* (B, C) formation in the oriented Xe* (3P2, MJ= 2) + oriented NF3reaction

Steric effect for the XeF* (B, C) formations in the oriented Xe* ((3)P(2), M(J) = 2) + oriented NF(3) reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orientation in the collision frame. Molecular steric opacity function has been determined as a function of the atomic orbital alignment (L(Z)') in the collision frame. The larger reactivity at the side with the smaller reactivity at the molecular axis direction is observed for the XeF* (B, C) channels at each atomic orbital alignment. A good correlation between the shape of the molecular steric opacity function and the molecular geometry of NF(3) is recognized. The L(Z)' selectivity in the molecular steric opacity function is different between the XeF* (B, C) channels; in the sideways direction, the XeF* (B) channel is favorable at L(Z)' = 0, while the XeF* (C) channel is favorable at |L(Z)'| = 1. In contrast, at the molecular axis direction, the XeF* (B) channel is favorable at |L(Z)'| = 1, while the XeF* (C) channel is favorable at L(Z)' = 0. We propose the collision-induced harpoon mechanism for the XeF* (B, C) formation in the Xe* ((3)P(2)) + NF(3) reaction.

Multidimensional Molecular Steric Opacity Function for XeCl*(B, C) Formation in the Oriented Xe* (3P2, MJ = 2) + Oriented CCl3F Reaction

The steric effect for the XeCl*(B, C) formations in the oriented Xe* (³P₂, MJ = 2) + oriented CCl₃F reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orbital alignment in the collision frame. Molecular steric opacity functions have been determined as a function of the atomic orbital alignment (M(L)') in the collision frame. The XeCl*(B, C) channels show similar molecular steric opacity functions at M(L)' = 0 but not at |M(L)'| = 1. The large molecular alignment dependence (i.e., the reactivity of the Cl₃ end and the F end is comparable, but a very poor reactivity for the sideway) is recognized for the XeCl*(B, C) channels except for the XeCl*(C) channel at |M(L)'| = 1, which shows an almost isotropic molecular orientation dependence. The M(L)' selectivity is different between the XeCl*(B, C) channels. At the molecular axis direction, the XeCl*(B) channel has little M(L)' selectivity whereas the XeCl*(C) channel is significantly favorable at M(L)' = 0. On the other hand, |M(L)'| = 1 is favorable at the sideway for the XeCl*(B, C) channels.

Multidimensional steric effect for the XeBr∗ (B, C) formation in the oriented Xe∗(P32, MJ=2)+oriented CF3Br reaction

Steric effect for the XeBr(*) (B, C) formation in the oriented Xe(*)((3)P(2), M(J) = 2) + oriented CF(3)Br reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orientation in the collision frame. Molecular steric opacity function has been determined as a function of the atomic orbital alignment (L(Z)(')) in the collision frame. The L(Z)(') selectivity in the molecular steric opacity function is different between the XeBr(*) (B, C) channels: For the XeBr(*) (C) channel, the L(Z)(') = 0 alignment is favorable at the molecular axis direction and the absolute value(L(Z)(')) = 1 alignment is favorable at the sideway direction, whereas for the XeBr(*) (B) channel, the L(Z)(') = 0 alignment is favorable at the sideway direction and the absolute value(L(Z)(')) = 1 alignment is favorable at the molecular axis direction. However, the shape of the steric opacity function for the XeBr(*) (B) channel at the L(Z)(') = 0 (and absolute value(L(Z)(')) = 1) alignment is similar to that for the XeBr(*) (C) channel at the absolute value(L(Z)(')) = 1 (and L(Z)(') = 0) alignment, respectively: A large molecular orientation dependence (i.e., the largest reactivity at the Br-end with the small molecular alignment dependence) is recognized for the XeBr(*) (B) channel at the L(Z)(') = 0 alignment and for the XeBr(*) (C) channel at the absolute value(L(Z)(')) = 1 alignment, whereas a large molecular alignment dependence (i.e., the largest reactivity at the Br-end with the poor reactivity at the sideway) is recognized for the XeBr(*) (B) channel at the absolute value(L(Z)(')) = 1 alignment and for the XeBr(*) (C) channel at the L(Z)(') = 0 alignment. We propose the indirect mechanism for the dark channels (Xe + Br + CF(3)) via the back-electron transfer from the CF(3) segment (or dissociating CF(3)...Br(-)) to Xe(+) as the origin of the significant molecular alignment dependence in the molecular steric opacity function.

Multi-dimensional steric effect for XeI* (B) formation in the oriented Xe* (3P2, MJ = 2) + oriented CH3I reaction

Multi-dimensional steric effect for the XeI* (B) formation in the oriented Xe* ((3)P(2), M(J) = 2) + oriented CH(3)I reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic alignment in the collision frame. The molecular steric opacity function has been determined as a function of the atomic orbital alignment. The large molecular orientation dependence (i.e., the largest reactivity at the I-end and the large difference in the reaction probability between the I-end and the CH(3)-end) and the large molecular alignment dependence (the poor reactivity at the sideway) is recognized for each atomic orbital alignment. In addition, a clear correlation between the molecular orientation and the atomic orbital alignment is recognized (i.e., the L(Z)' = 0 atomic orbital alignment is favorable for the molecular axis direction, while the |L(Z)'| = 1 atomic orbital alignment is favorable for the sideway direction).

Multidimensional steric effects for the XeI∗ (B, C) formations in the oriented Xe∗ (P32,MJ=2)+oriented CF3I reaction

Steric effects for the XeI(*) (B) and XeI(*) (C) formations in the oriented Xe(*) ((3)P(2),M(J)=2)+oriented CF(3)I reaction have been observed as a function of the mutual configuration between molecular orientation and atomic alignment in the collision frame. The mutual configuration exercises the significant influences on the stereoanisotropy for both the reactivity and the branching to the XeI(*) (B) and XeI(*) (C) channels.

Predicting transmembrane helix pair configurations with knowledge‐based distance‐dependent pair potentials

As a first step toward a novel de novo structure prediction approach for alpha-helical membrane proteins, we developed coarse-grained knowledge-based potentials to score the mutual configuration of transmembrane (TM) helices. Using a comprehensive database of 71 known membrane protein structures, pairwise potentials depending solely on amino acid types and distances between C(alpha)-atoms were derived. To evaluate the potentials, they were used as an objective function for the rigid docking of 442 TM helix pairs. This is by far the largest test data set reported to date for that purpose. After clustering 500 docking runs for each pair and considering the largest cluster, we found solutions with a root mean squared (RMS) deviation <2 A for about 30% of all helix pairs. Encouragingly, if only clusters that contain at least 20% of all decoys are considered, a success rate >71% (with a RMS deviation <2 A) is obtained. The cluster size thus serves as a measure of significance to identify good docking solutions. In a leave-one-protein-family-out cross-validation study, more than 2/3 of the helix pairs were still predicted with an RMS deviation <2.5 A (if only clusters that contain at least 20% of all decoys are considered). This demonstrates the predictive power of the potentials in general, although it is advisable to further extend the knowledge base to derive more robust potentials in the future. When compared to the scoring function of Fleishman and Ben-Tal, a comparable performance is found by our cross-validated potentials. Finally, well-predicted "anchor helix pairs" can be reliably identified for most of the proteins of the test data set. This is important for an extension of the approach towards TM helix bundles because these anchor pairs will act as "nucleation sites" to which more helices will be added subsequently, which alleviates the sampling problem.