Voluntary Participation and Spite in Public Good Provision Experiments: an International Comparison.

This paper studies public good provision in the laboratory using voluntary contribution mechanism, in a cross-cultural experiment conducted in the United States and Japan.EXPERIMENTS ; SOCIAL CHOICE ; PUBLIC GOODS

Voluntary Participation Game Experiments with a Non-Excludable Public Good: Is Spitefulness a Source of Cooperation?.

Economic theory predicts that it is impossible to have cooperation in finitely repeated games such as a prisoner's dilemma game without communication. In an experiment on a voluntary participation game with a non-excludable public good that is a version of a Hawk-Dove game, we obderved that evolutionary stable strategies did not appear, but cooperation emerged through a transmutation from the Hawk-Dove game to a game where a dominant strategy outcome is Pareto efficient.GAME THEORY ; EXPERIMENTS

Laboratory Simulation of Laser Communications from a Reentry Vehicl

Laser communications has been proposed as one way to solve the radio blackout problem during the reentry of a manned vehicle. The AMICOM 8,000 kW Plasma Facility (PF)1 \u27 2 was used in a set of experiments to simulate the conditions expected during the reentry of a high speed vehicle. This experimental study was designed to simulate a typical theoretical Apollo test vehicle reentry trajectory. No plasma effects on the transmitted laser beam were expected or observed since the cutoff frequency due to electron collision rates was calculated to be in the microwave region and not in the optical or infrared region. However, the high temperature gradients and anticipated gas density variations in the flow field were throught to be potential sources of local index of refraction fluctuations. These fluctuations may generate scintillation effects in the laser beam which would be expected to reduce the effectiveness of laser communications. The limitation of maximum power in the PF flow field, approximately 4 megawatts, prevented simultaneous duplication of the desired Reynolds number (R ^ 7 X 104 per meter) and the stagnation point enthalpy (h/RT o « 100). However, by varying the PF parameters to lower the enthalpy, the Reynolds number, or both a satisfactory simulation of conditions just before the termination of radio blackout was obtained. The region of the reentry corridor simulated in this investigation is near 60 km altitude and 3.9 km/sec velocity. The Reynolds numbers were based on a characteristic length of 1 meter for the vehicle and 0.1 meter for the model. A flat disk model, normal to the PF flow stream, was used to generate the required local flow field for the laser experiments. The disk diameter, 0.09 m, was determined by the PF flow field blockage parameter; this also established the characteristic Reynolds number length (j£• Ki 0.1 m) for the experiments. The disk was followed by a smaller diameter cylindrical afterbody approximately 25 cm long containing instrumentation. The cylinder also had a pair of windows situated so the laser beam could pass through the flow field immediately behind the disk. An amplitude modulated He-Ne laser was used as a signal source with a photomultiplier tube as a detector. Model stagnation pressure and transmitted laser signals were recorded on an analog tape recorder. A frequency spectrum analyzer was used to analyze the data

pi^0 pi^0 Scattering Amplitudes and Phase Shifts Obtained by the pi^- P Charge Exchange Process

The results of the analysis of the pi^0 pi^0 scattering amplitudes obtained with pi^- P charge exchange reaction, pi^- P --> pi^0 pi^0 n, data at 9 GeV/c are presented. The pi^0 pi^0 scattering amplitudes show clear f_0(1370) and f_2(1270) signals in the S and D waves, respectively. The pi^0 pi^0 scattering phase shifts have been obtained below Kbar K threshold and been analyzed by the Interfering Amplitude method with introduction of negative background phases. The results show a S wave resonance, sigma. Its Breit-Wigner parameters are in good agreement with those of our previous analysis on the pi^+ pi^- phase shift data.Comment: 4 pages, 4 figures. Proceedings of the int. conf. Hadron'99 at Beijing, Aug. 1999. Presented for the collaboration of A.M.Ma, K.Takamatsu, M.Y.Ishida, S.Ishida, T.Ishida, T. Tsuru and H. Shimizu, and the E135 collaboration. For our activities on sigma, visit http://amaterasu.kek.jp/sigm

Oncogenic Virome Benefits from the Different Vaginal Microbiome-Immune Axes.

The picture of dynamic interaction between oncogenic viruses and the vaginal bacteria-immune host milieu is incomplete. We evaluated the impact of Polyomaviridae, Papillomaviridae, and Herpesviridae oncoviruses on the vaginal Community State Types (CSTs) and host immune response in reproductive-age women. In our cohort, only Polyomaviridae and Papillomaviridae were detected and were associated with changes in the resident bacteria of CST I and IV (p < 0.05). Lactobacillus crispatus increased in CST I while Prevotella timonensis and Sneathia sanguinegens increased in CST IV. Conversely, CST II and III showed an alteration of the immune response, with the decrease of Eotaxin, MCP-1, IL-7, IL-9, and IL-15 (p < 0.05), leading to reduced antiviral efficacy. An efficient viral clearance was observed only in women from CST I, dominated by Lactobacillus crispatus. Our in vivo study begins to address the knowledge gap with respect to the role of vaginal bacteria and immune response in susceptibility to oncoviral infections

Search for Exotic Mesons in pi- P Interactions at 18 GeV/c

The recent search for non $q \bar{q}$ mesons in $\pi^{-}p$ interactions at Brookhaven National Laboratory is summarized. Many final states such as $\eta \pi$, $\eta' \pi^{-}$, $a_{0} \pi$, $f_{1} \pi$, $a_{2} \pi$, $b_{1} \pi$, which are favored decay modes of exotics, are under investigation.Comment: 9 pages, PostScript, Presented at the International School of Nuclear Physics, Erice, Sicily, Italy, September 199