The effect of group interaction processes on performance in time-series extrapolation

Abstract: This study explores the ability of groups to forecast and establish judgmental confidence intervals in time series extrapolation. Thirty-six three-person groups were used to evaluate four different group interaction processes. In addition to staticized, nominal group technique and consensus processes, the study utilizes a modified consensus process, where a selected group member completes the task prior to group discussion and interaction. Using real life time series, subjects produced forecasts and related confidence intervals for six periods. Groups in the modified-consensus structuring process exhibited significantly greater forecast accuracy than all other experimental conditions ( p < 0.001). The superiority was most pronounced for series of high forecast difficulty. These results are discussed in relation to the contribution of the initial estimates as an anchor on which the modified-consensus group can focus

Matrix Models for Supersymmetric Chern-Simons Theories with an ADE Classification

We consider N=3 supersymmetric Chern-Simons (CS) theories that contain product U(N) gauge groups and bifundamental matter fields. Using the matrix model of Kapustin, Willett and Yaakov, we examine the Euclidean partition function of these theories on an S^3 in the large N limit. We show that the only such CS theories for which the long range forces between the eigenvalues cancel have quivers which are in one-to-one correspondence with the simply laced affine Dynkin diagrams. As the A_n series was studied in detail before, in this paper we compute the partition function for the D_4 quiver. The D_4 example gives further evidence for a conjecture that the saddle point eigenvalue distribution is determined by the distribution of gauge invariant chiral operators. We also see that the partition function is invariant under a generalized Seiberg duality for CS theories.Comment: 20 pages, 3 figures; v2 refs added; v3 conventions in figure 3 altered, version to appear in JHE

β-MnO2 ACTIVATION OF PEROXYMONOSULFATE FOR CATALYTIC PHENOL DEGRADATION IN AQUEOUS SOLUTIONS

β-MnO2 was prepared and used to activate peroxymonosulphate for degradation of aqueous phenol. The sample was characterized by N2 adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM). The catalyst is highly effective in heterogeneous activation of PMS to produce sulfate radicals for phenol degradation compared with homogeneous oxidatiom. β-MnO2 could completely remove phenol in 30 min at the conditions of 25 ppm phenol, 0.4 g/L catalyst, 2 g/L PMS, and 25 oC. A pseudo first order model would fit to phenol degradation kinetics and activation energy was obtained as 38.2 kJ/mol

Pressure-dependent EPANET extension

In water distribution systems (WDSs), the available flow at a demand node is dependent on the pressure at that node. When a network is lacking in pressure, not all consumer demands will be met in full. In this context, the assumption that all demands are fully satisfied regardless of the pressure in the system becomes unreasonable and represents the main limitation of the conventional demand driven analysis (DDA) approach to WDS modelling. A realistic depiction of the network performance can only be attained by considering demands to be pressure dependent. This paper presents an extension of the renowned DDA based hydraulic simulator EPANET 2 to incorporate pressure-dependent demands. This extension is termed “EPANET-PDX” (pressure-dependent extension) herein. The utilization of a continuous nodal pressure-flow function coupled with a line search and backtracking procedure greatly enhance the algorithm’s convergence rate and robustness. Simulations of real life networks consisting of multiple sources, pipes, valves and pumps were successfully executed and results are presented herein. Excellent modelling performance was achieved for analysing both normal and pressure deficient conditions of the WDSs. Detailed computational efficiency results of EPANET-PDX with reference to EPANET 2 are included as well

Brain oscillatory activity as a biomarker of motor recovery in chronic stroke

In the present work, we investigated the relationship of oscillatory sensorimotor brain activity to motor recovery. The neurophysiological data of 30 chronic stroke patients with severe upper‐limb paralysis are the basis of the observational study presented here. These patients underwent an intervention including movement training based on combined brain–machine interfaces and physiotherapy of several weeks recorded in a double‐blinded randomized clinical trial. We analyzed the alpha oscillations over the motor cortex of 22 of these patients employing multilevel linear predictive modeling. We identified a significant correlation between the evolution of the alpha desynchronization during rehabilitative intervention and clinical improvement. Moreover, we observed that the initial alpha desynchronization conditions its modulation during intervention: Patients showing a strong alpha desynchronization at the beginning of the training improved if they increased their alpha desynchronization. Patients showing a small alpha desynchronization at initial training stages improved if they decreased it further on both hemispheres. In all patients, a progressive shift of desynchronization toward the ipsilesional hemisphere correlates significantly with clinical improvement regardless of lesion location. The results indicate that initial alpha desynchronization might be key for stratification of patients undergoing BMI interventions and that its interhemispheric balance plays an important role in motor recovery.Bundesministerium für Bildung und Forschung, Grant/Award Numbers: 13GW0053, 16SV7754; Deutsche Forschungsgemeinschaft; Deutscher Akademischer Austauschdienst, Grant/Award Number: 9156335

Correlated two-pion exchange and large-N(C) behavior of nuclear forces

The effect of correlated scalar-isoscalar two-pion exchange (CrTPE) modes is considered in connection with central and spin-orbit parts of the NN force. The two-pion correlation function is coupled directly to the scalar form factor of the nucleon which we calculate in the large-N(C) limit where the nucleon can be described as a soliton of an effective chiral theory. The results for the central NN force show a strong repulsive core at short internucleon distances supplemented by a moderate attraction beyond 1 fm. The long-range tail of the central NN potential is driven by the the pion-nucleon sigma term and consistent with the effective $\sigma$ meson exchange. The spin-orbit part of the NN potential is repulsive. The large-N(C) scaling behavior of the scalar-isoscalar NN interaction is addressed. We show that the spin-orbit part is O(1/N^2(C)) in strength relative to the central force resulting in the ratio $\simeq 1/9$ suggested by the 1/N(C) expansion for N(C)=3. The latter is in agreement with our numerical analysis and with the Kaplan-Manohar large-N(C) power counting. Unitarization of the $\pi \pi$ scattering amplitude plays here an important role and improves the tree level results. Analytical representations of the CrTPE NN potential in terms of elementary functions are derived and their chiral content is discussed.Comment: 29 pages, 7 figure

TowardSelf-Replication of Robot Control Circuitry by Self-Inspection

Abstract. The concept of man-made self-replicatingm achines was first proposed by John von Neumann more t han5 0 years ago. However, t hereh as never been aphysical implementation of his universalconstructor architectureas a robotic system.Prior too ur other recent work,a nautonomous self-replicating mechanical s ystem hadn ot been developed. In t his paper, w ed emonstrateanon-von-Neumann architecturef or the replication of transistor circuits by active self-inspection. That is, therearen oi nstructions stored about how toconstruct the circuit,b ut information observed about the spatial organization of the originalcircuit drives alarger electromechanical( robotic) system in whichi t is embedded tocause the production of a replica of the originalcircuit.In the workp resented here,only replication of the control circuit is of interest.In the current context, the electromechanicalh ardwarei s viewed as a tool whichi s manipulated by the control circuit for its own reproduction.This architecturalp aradigm is demonstrated with prototypes that are reviewed hereand compared withani mplementation of the universal constructor concept. 1Introduction 1.1Motivation The concept of man-made self-replicatingmachines was first proposed by John von Neumann more thanf ifty years ag