Broken Telephone: Analysis of a Reinforced Process

We consider the following $L$ player co-operative signaling game. Nature plays from the set $\{0,0\u27\}$. Nature\u27s play is observed by Player 1 who then plays from the set $\{1,1\u27\}$. Player 1\u27s play is observed by Player 2. Player 2 then plays from the set $\{2,2\u27\}$. Player 2\u27s play is observed by player 3. This continues until Player L observes Player L-1\u27s play. Player L then guesses Nature\u27s play. If he guesses correctly, then all players win. We consider an urn scheme for this where each player has two urns, labeled by the symbols they observe. Each urn has balls of two types, represented by the two symbols the player controlling the urn is allowed to play. At each stage each player plays by drawing from the appropriate urn, with replacement. After a win each player reinforces by adding a ball of the type they draw to the urn from which it was drawn. We attempt to show that this type of urn scheme achieves asymptotically optimal coordination. A lemma remains unproved but we have good numerical evidence for it\u27s truth

Computing optimal strategies for a cooperative hat game

We consider a `hat problem' in which each player has a randomly placed stack of black and white hats on their heads, visible to the other player, but not the wearer. Each player must guess a hat position on their head with the goal of both players guessing a white hat. We address the question of finding the optimal strategy, i.e., the one with the highest probability of winning, for this game. We provide an overview of prior work on this question, and describe several strategies that give the best known lower bound on the probability of winning. Upper bounds are also considered here

Dictator Games: A Meta Study

Over the last 25 years, more than a hundred dictator game experiments have been published. This meta study summarizes the evidence. Exploiting the fact that most experiments had to fix parameters they did not intend to test, the meta study explores a rich set of control variables for multivariate analysis. It shows that Tobit models (assuming that dictators would even want to take money) and hurdle models (assuming that the decision to give a positive amount is separate from the choice of amount, conditional on giving) outperform mere meta-regression and OLS

Broken telephone, an analysis of a reinforced process

We consider the following L player co-operative signaling game. Nature plays from the set {0,0\u27}. Nature\u27s play is observed by Player 1 who then plays from the set {1,1\u27} . Player 1\u27s play is observed by Player 2. Player 2 then plays from the set {2,2\u27} . Player 2\u27s play is observed by player 3. This continues until Player L observes Player L-1\u27s play. Player L then guesses Nature\u27s play. If he guesses correctly, then all players win. We consider an urn scheme for this where each player has two urns, labeled by the symbols they observe. Each urn has balls of two types, represented by the two symbols the player controlling the urn is allowed to play. At each stage each player plays by drawing from the appropriate urn, with replacement. After a win each player reinforces by adding a ball of the type they draw to the urn from which it was drawn. We attempt to show that this type of urn scheme achieves asymptotically optimal coordination. A lemma remains unproved but we have good numerical evidence for it\u27s truth

Broken telephone, an analysis of a reinforced process

We consider the following L player co-operative signaling game. Nature plays from the set {0,0\u27}. Nature\u27s play is observed by Player 1 who then plays from the set {1,1\u27} . Player 1\u27s play is observed by Player 2. Player 2 then plays from the set {2,2\u27} . Player 2\u27s play is observed by player 3. This continues until Player L observes Player L-1\u27s play. Player L then guesses Nature\u27s play. If he guesses correctly, then all players win. We consider an urn scheme for this where each player has two urns, labeled by the symbols they observe. Each urn has balls of two types, represented by the two symbols the player controlling the urn is allowed to play. At each stage each player plays by drawing from the appropriate urn, with replacement. After a win each player reinforces by adding a ball of the type they draw to the urn from which it was drawn. We attempt to show that this type of urn scheme achieves asymptotically optimal coordination. A lemma remains unproved but we have good numerical evidence for it\u27s truth

On levine's notorious hat puzzle

The Levine hat game requires n players, each wearing an infinite random stack of black and white hats, to guess the location of a black hat on their own head seeing only the hats worn by all the other players. They are allowed a strategy session before the game, but no further communication. The players collectively win if and only if all their guesses are correct. In this paper, we give an overview of what is known about strategies for this game, including an extended discussion of the case with n =2 players (and a conjecture for an optimal strategy in this case). We also prove that Vn, the optimal value of the joint success probability in the n-player game, is a strictly decreasing function of n.SCOPUS: ch.binfo:eu-repo/semantics/publishe

On levine's notorious hat puzzle

The Levine hat game requires n players, each wearing an infinite random stack of black and white hats, to guess the location of a black hat on their own head seeing only the hats worn by all the other players. They are allowed a strategy session before the game, but no further communication. The players collectively win if and only if all their guesses are correct. In this paper we give an overview of what is known about strategies for this game, including an extended discussion of the case with n = 2 players (and a conjecture for an optimal strategy in this case). We also prove that Vn, the optimal value of the joint success probability in the n-player game, is a strictly decreasing function of n.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The effect of prophylaxis with ertapenem versus cefuroxime/metronidazole on intestinal carriage of carbapenem-resistant or third-generation-cephalosporin-resistant Enterobacterales after colorectal surgery

Objectives: Compared to cephalosporin-based prophylaxis, ertapenem prophylaxis lowers the risk of surgical site infection among carriers of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PEs) undergoing colorectal surgery. We aimed to determine whether ertapenem prophylaxis leads to increased postoperative colonization with carbapenem-resistant Enterobacterales (CREs) and third-generation-cephalosporin-resistant Enterobacterales (3GCR-Es). Methods: This study was nested within a quality improvement study of prophylaxis for ESBL-PE carriers undergoing colorectal surgery. Patients were screened 4-6 days after surgery for carriage of ESBL-PEs or other 3GCR-Es and CREs. When CREs were detected, pre-and postsurgical clones were compared using Fourier-transform infrared (FT-IR) spectroscopy. Results: The sample consisted of 56 patients who carried ESBL-PEs before surgery and received cefuroxime/metronidazole prophylaxis (Group 1), 66 who carried ESBL-PEs before surgery and received ertapenem (Group 2), and 103 ESBL-PE non-carriers who received cefuroxime/metronidazole prophylaxis (Group 3). CRE carriage was detected postoperatively in one patient (1.5%) in Group 2 versus eight patients (14.3%) in Group 1 (RD-12.8%; 95%CI-22.4% to-3.1%). For seven out of nine patients, preoperative ESBL-PE and postoperative CRE isolates were compared; in five of them, the pre-and postoperative clones were identical. Postoperative 3GCR-E carriage was detected in 37 patients (56.1%) in Group 2 versus 46 patients in Group 1 (82.1%) (aRD-20.7%, 95%CI-37.3% to-4.1%). Conclusions: Among ESBL-PE carriers undergoing colorectal surgery, detection of short-term postsurgical colonization by CREs and 3GCR-Es was significantly lower among patients who received ertapenem prophylaxis than those who received cephalosporin-metronidazole prophylaxis. Resistance development in a colonizing bacterial clone, rather than carbapenemase acquisition, was the major mechanism of carbapenem resistance.</p

Treatment of pouchitis, Crohn\u27s disease, cuffitis, and other inflammatory disorders of the pouch: consensus guidelines from the International Ileal Pouch Consortium.

Pouchitis, Crohn\u27s disease of the pouch, cuffitis, polyps, and extraintestinal manifestations of inflammatory bowel disease are common inflammatory disorders of the ileal pouch. Acute pouchitis is treated with oral antibiotics and chronic pouchitis often requires anti-inflammatory therapy, including the use of biologics. Aetiological factors for secondary pouchitis should be evaluated and managed accordingly. Crohn\u27s disease of the pouch is usually treated with biologics and its stricturing and fistulising complications can be treated with endoscopy or surgery. The underlying cause of cuffitis determines treatment strategies. Endoscopic polypectomy is recommended for large, symptomatic inflammatory polyps and polyps in the cuff. The management principles of extraintestinal manifestations of inflammatory bowel disease in patients with pouches are similar to those in patients without pouches