Best-shot versus weakest-link in political lobbying: an application of group all-pay auction

We analyze a group political lobbying all-pay auction with a group specific public good prize, in which one group follows a weakest-link and the other group follows a best-shot impact function. We completely characterize all semi-symmetric equilibria. There are two types of equilibria: (1) each player in the best-shot group puts mass at the upper bound of the support, whereas each player in the other group puts mass at the lower bound of the support; (2) players in the best-shot group put masses at both the lower and the upper bounds, while the other group randomizes without a mass point. An earlier and longer version of this study was circulated under the title “The Group All-pay Auction with Heterogeneous Impact Functions.” We appreciate the comments of an Associate Editor and two anonymous referees, Kyung Hwan Baik, Walter Enders, Matt Van Essen, Paan Jindapon, David Malueg, Paul Pecorino, Seth Streitmatter, Ted Turocy, the participants at the 2015 conference of ‘Contest: Theory and Evidence’ at the University of East Anglia, and the seminar participants at the University of Alabama and Korea University. Iryna Topolyan gratefully acknowledges the support from the Charles Phelps Taft Research Center. Any remaining errors are our own

Close Correlation of Monoamine Oxidase Activity with Progress of Alzheimer’s Disease in Mice, Observed by in Vivo Two-Photon Imaging

Monoamine oxidases (MAOs) play an important role in Alzheimer's disease (AD) pathology. We report in vivo comonitoring of MAO activity and amyloid-beta (A beta) plaques dependent on the aging of live mice with AD, using a two-photon fluorescence probe. The probe under the catalytic action of MAO produces a dipolar fluorophore that senses A beta plaques, a general AD biomarker, enabling us to comonitor the enzyme activity and the progress of AD indicated by A beta plaques. The results show that the progress of AD has a close correlation with MAO activity, which can be categorized into three stages: slow initiation stage up to three months, an aggressive stage, and a saturation stage from nine months. Histological analysis also reveals elevation of MAO activity around A beta plaques in aged mice. The close correlation between the MAO activity and AD progress observed by in vivo monitoring for the first time prompts us to investigate the enzyme as a potential biomarker of AD.1195Ysciescopu

Using Incentives and Social Information to Promote Energy Conservation Behavior

Improving the efficiency in the domestic energy consumption has become a showpiece of how behavioral economics can be applied to the field of environmental economics. This study builds upon the literature by providing subjects with individual and social energy performance information at group level in a controlled field experiment setting. We aim to test whether extrinsic incentives accentuate or crowd out the intrinsic motivation to save energy and how heterogeneity in environmental attitudes also impacts on electricity conservation. Besides, we test for the persistence of energy-saving habits after the information is removed. Results suggest that the provision of individual feedback and social information increase energy conserving behavior, with this being most effective among those who signaled in a previous stage preferences for pro-environmental and sustainable living. However, treatment variations indicate that subjects overall fail to maintain “good habits” once the intervention stops, with exception of pro-environmental subjects who continue to consume less electricity in the post-intervention phase. Furthermore, our findings indicate that rewarding groups in a competitive environment may create perverse long-run effects. While providing individual and social information could improve both consumer welfare and energy demand forecasting, the timescale, frequency, and mechanism undertaken require careful scrutiny and planning if these potential benefits are to be maximized and undesirable side effects prevented

Chemical interaction between sigma 1140+SiC fibre and Ti-6Al-4V

The interfacial chemical reaction between 1140+SiC and a Ti-6Al-4V matrix was investigated. The growth behavior of the resulting interfacial reaction layer during manufacture and high temperature exposure were also studied. The activation energy and growth rate were compared for the interfacial reaction

Optimisation of concurrent fibre winding and low pressure plasma spraying for the manufacture of titanium matrix composite rings

A concurrent fibre winding and low pressure plasma spraying (LPPS) process has been developed to manufacture multiply fibre reinforced titanium matrix composite (TMC) rings in a single spraying operation. Optimisation of the LPPS parameters has been successively performed for two different sizes of Ti-6Al-4V powders by experimental design and statistical analysis, which provided minimimum porosity and surface roughness for both powders. The most important LPPS parameters affecting porosity and surface roughness of deposits were Ar gas flow rate and chamber pressure. During TMC manufacture, the coarse Ti-6Al-4V powder spraying provided enhanced infiltration between fibres but caused degradation of fibre tensile strength, as well as a rough ring surface. The fine Ti-6Al-4V powder gave no significant degradation of fibre strength and a relatively smooth ring surface. 4 ply SiC fibre reinforced TMCs manufactured by the spray-wind process have also been evaluated in terms of porosity, fibre distribution and fibre damage

Process study, microstructure, and matrix cracking of SiC fiber reinforced MoSi2 based composites

SiC fiber reinforced SiAlON-MoSi2 composites have been manufactured by a concurrent fiber winding and low pressure plasma spraying (LPPS) technique to produce a multilayer, circumferentially fiber reinforced composite ring. The LPPS parameters for SiAlON-MoSi2 powder were optimized by a two-level experimental design approach followed by further optimization, which provided a smooth sprayed surface, low matrix porosity, and high deposition efficiency. The microstructure of SiAlON-MoSi2 matrix consisted of a lamellar structure built up of individual splats and a uniform distribution of discontinuous SiAlON splats throughout the MoSi2 matrix. The spray/wind composites exhibited 2% porosity and well-controlled fiber distribution. High temperature consolidation led to the formation of a thick reaction zone at the fiber-matrix interface by a chemical reaction between C coating and MoSi2. Matrix cracking occurred in SiCf (15 vol.%)/MoSi2 after cooling from 1500 to 25 °C and was attributed to the large tensile residual stresses in the matrix developed on cooling because of coefficient of thermal expansion (CTE) mismatch between matrix and fiber. The addition of 40 vol.% SiAlON into the MoSi2 effectively eliminated the matrix cracking by reducing the matrix-fiber CTE mismatch. Predictions of matrix cracking stress on the basis of residual stresses in the composites showed that the maximum permissible fiber volume fraction to avoid matrix cracking was 6% for SiCf/MoSi2 and 23% for SiCf/SiAlON(40 vol.%)-MoSi2

Optimisation of vacuum plasma spraying for composite production

The porosity and surface roughness of plasma sprayed composite monotapes are important factors controlling final composite quality in the manufacture of metal matrix composites by plasma spraying. In order to minimise porosity and surface roughness, the effects of vacuum plasma spray parameters on the porosity and the surface roughness of a Al-12wt%Si monolithic alloy have been evaluated by an experimental design method. The results showed that powder size, hydrogen gas flow rate, and powder feed rate had a strong effect on porosity and surface roughness. Statistical analysis of experimental results has been used to improve the quality of plasma sprayed deposits by prediction of optimised vacuum plasma spray parameters. Subsequent monolithic deposit manufacture under optimum conditions gave good agreement with predicted porosity and surface roughness. Optimised conditions were then used to fabricate Al-12wt%Si monotapes reinforced with stainless steel fibres with minimum porosity and surface roughness. After monotape consolidation, the fibres retained their regular spacing, which may be attributed to the small amount of matrix plastic flow required for full consolidation