Classical transverse Ising spin glass with short- range interaction beyond the mean field approximation

The classical transverse field Ising spin- glass model with short-range interactions is investigated beyond the mean- field approximation for a real d- dimensional lattice. We use an appropriate nontrivial modification of the Bethe- Peierls method recently formulated for the Ising spin- glass. The zero- temperature critical value of the transverse field and the linear susceptibility in the paramagnetic phase are obtained analytically as functions of dimensionality d. The phase diagram is also calculated numerically for different values of d. In the limit d -> infinity, known mean- field results are consistently reproduced.Comment: LaTex, 11 pages, 2 figure

Impact of the "when the fun stops, stop" gambling message on online gambling behaviour: a randomised, online experimental study

Background: Safer gambling messages are a common freedom-preserving method of protecting individuals from gambling-related harm. Yet, there is little independent and rigorous evidence assessing the effectiveness of safer gambling messages. In our study, we aimed to test the effect of the historically most commonly-used UK safer gambling message on concurrent gambling behaviour of people who gamble in the UK. / Methods: In this study, three preregistered, incentivised, and randomised online experiments, testing the UK's “when the fun stops, stop” message, were carried out via the crowdsourcing platform Prolific. Adults based in the UK who had previously participated in the gambling activities relevant to each experiment were eligible to participate. Experiments 1 and 3 involved bets on real soccer events, and experiment 2 used a commercially available online roulette game. Safer gambling message presence was varied between participants in each experiment. In experiment 2, exposed participants could be shown either a yellow or a black-and-white version of the safer gambling message. Participants were provided with a monetary endowment with which they were allowed to bet. Any of this money not bet was afterwards paid to participants as a bonus, in addition to the payouts from any winning bets. In experiment 2 participants had the opportunity to re-wager any winnings from the roulette game. The primary outcome in experiment 1 was participants’ decisions to accept (or reject) a series of football bets, which varied in their specificity (and payoffs), and the primary outcomes of experiments 2 and 3 were the proportion of available funds bet, which were defined as the total amount of money bet by a participant out of the total that could have been bet. / Findings: Participants for all three experiments were recruited between May 17, 2019, and Oct 17, 2020. Of the 506 participants in experiment 1, 41·3% of available bets were made by the 254 participants in the gambling message condition, which was not significantly different (p=0·15, odds ratio 1·22 [95% CI 0·93 to 1·61]) to the 37·8% of available bets made by the 252 participants in the control condition. In experiment 2, the only credible difference between conditions was that the 501 participants in the condition with the yellow version of the gambling message bet 3·64% (95% Bayesian credibility interval 0·00% to 7·27%) more of available funds left over than the 499 participants in the control condition. There were no credible differences between the bets made by the 500 participants in the black-and-white gambling message condition and the other conditions. In experiment 3, there were no credible differences between the 502 participants in the gambling message condition and the 501 participants in the control condition, with the largest effect being a 5·87% (95% Bayesian credibility interval –1·44% to 13·20%) increase in the probability of betting everything in the gambling message condition. / Interpretation: In our study, no evidence was found for a protective effect of the most common UK safer gambling message. Alternative interventions should be considered as part of an evidence-based public health approach to reducing gambling-related harm. / Funding: University of Warwick, British Academy and Leverhume, Swiss National Science Foundation

History Dependent Phenomena in the Transverse Ising Ferroglass: the Free Energy Landscape

In this paper we investigate the relationship between glassy and ferromagnetic phases in disordered Ising ferromagnets in the presence of transverse magnetic fields, $\Gamma$. Iterative mean field simulations probe the free energy landscape and suggest the existence of a glass transition as a function of $\Gamma$ which is distinct from the Curie temperature. New experimental field-cooled and zero-field-cooled data on LiHo$_x$Y$_{1-x}$F$_4$ provide support for our theoretical picture.Comment: 4 pages RevTex; 5 figure

A speed-of-play limit reduces gambling expenditure in an online roulette game: Results of an online experiment

UK online casino games are presently not subject to any limitations on speed-of-play or stakes. One recent policy proposal is to ensure that no online casino game can be played faster than its in-person equivalent. Another policy proposal is to limit the maximum stakes on online casino games to £2, to match the current stake limit on electronic gambling machines. This research experimentally investigated the speed-of-play proposal subject to a £2 stake limit, in an online experiment using incentivized payouts based on £4 endowments and a commercial online roulette game, which was slowed-down in one condition to enforce a speed-of-play limit of one spin every 60 seconds. UK residents, aged 18 years and over and with experience in playing online roulette (N = 1,002), were recruited from an online crowdsourcing panel. In the slowed-down condition there was a credible reduction in the amount gambled. This effect occurred via a credible reduction in the mean number of spins which outweighed any potential increases in bet sizes. Speed-of-play limits may be effective in reducing gambling expenditure for online roulette

Ground-State Phase Diagram of the Two-Dimensional Quantum Heisenberg Mattis Model

The two-dimensional $S=1/2$ asymmetric Heisenberg Mattis model is investigated with the exact diagonalization of finite clusters. The N\'eel order parameter and the spin glass order parameter can be smoothly extrapolated to the thermodynamic limit in the antiferromagnetic region, as in the pure Heisenberg antiferromagnet. The critical concentration of the N\'eel phase is consistent with that of the two-dimensional Ising Mattis model, and the spin glass order parameter increases monotonously as the ferro-bond concentration increases. These facts suggest that quantum fluctuation does not play an essential role in two-dimensional non-frustrated random spin systems. KEYWORDS: quantum spin system, ground state, randomness, Mattis model, N\'eel order, spin glass orderComment: 10 pages, LaTeX, 6 compressed/uuencoded postscript figures, J. Phys. Soc. Jpn. 65 (1996) No. 2 in pres

First-order transitions and triple point on a random p-spin interaction model

The effects of competing quadrupolar- and spin-glass orderings are investigated on a spin-1 Ising model with infinite-range random $p$-spin interactions. The model is studied through the replica approach and a phase diagram is obtained in the limit $p\to\infty$. The phase diagram, obtained within replica-symmetry breaking, exhibits a very unusual feature in magnetic models: three first-order transition lines meeting at a commom triple point, where all phases of the model coexist.Comment: 9 pages, 2 ps figures include

Beam Instrumentation for CRYRING@@ESR

BACKGROUND: The disulfide-bonded region (DSR) of HIV-1 gp41 mediates association with gp120 and plays a role in transmission of receptor-induced conformational changes in gp120 to gp41 that activate membrane fusion function. In this study, forced viral evolution of a DSR mutant that sheds gp120 was employed to identify domains within gp120-gp41 that are functionally linked to the glycoprotein association site. RESULTS: The HIV-1AD8 mutant, W596L/K601D, was serially passaged in U87.CD4.CCR5 cells until replication was restored. Whereas the W596L mutation persisted throughout the cultures, a D601H pseudoreversion in the DSR partially restored cell-free virus infectivity and virion gp120-gp41 association, with further improvements to cell-free virus infectivity following a 2nd-site D674E mutation in the membrane-proximal external region (MPER) of gp41. In an independent culture, D601H appeared with a deletion in V4 (Thr-394-Trp-395) and a D674N substitution in the MPER, however this MPER mutation was inhibitory to W596L/K601H cell-free virus infectivity. While cell-free virus infectivity was not fully restored for the revertant genotypes, their cell-to-cell transmission approached the levels observed for WT. Interestingly, the functional boost associated with the addition of D674E to W596L/K601H was not observed for cell-cell fusion where the cell-surface expressed glycoproteins function independently of virion assembly. The W596L/K601H and W596L/K601H/D674E viruses exhibited greater sensitivity to neutralization by the broadly reactive MPER directed monoclonal antibodies, 2F5 and 4E10, indicating that the reverting mutations increase the availability of conserved neutralization epitopes in the MPER. CONCLUSIONS: The data indicate for the first time that functional crosstalk between the DSR and MPER operates in the context of assembled virions, with the Leu-596-His-601-Glu-674 combination optimizing viral spread via the cell-to-cell route. Our data also indicate that changes in the gp120-gp41 association site may increase the exposure of conserved MPER neutralization epitopes in virus