A Survey on Approximation Mechanism Design without Money for Facility Games

In a facility game one or more facilities are placed in a metric space to serve a set of selfish agents whose addresses are their private information. In a classical facility game, each agent wants to be as close to a facility as possible, and the cost of an agent can be defined as the distance between her location and the closest facility. In an obnoxious facility game, each agent wants to be far away from all facilities, and her utility is the distance from her location to the facility set. The objective of each agent is to minimize her cost or maximize her utility. An agent may lie if, by doing so, more benefit can be obtained. We are interested in social choice mechanisms that do not utilize payments. The game designer aims at a mechanism that is strategy-proof, in the sense that any agent cannot benefit by misreporting her address, or, even better, group strategy-proof, in the sense that any coalition of agents cannot all benefit by lying. Meanwhile, it is desirable to have the mechanism to be approximately optimal with respect to a chosen objective function. Several models for such approximation mechanism design without money for facility games have been proposed. In this paper we briefly review these models and related results for both deterministic and randomized mechanisms, and meanwhile we present a general framework for approximation mechanism design without money for facility games

Theology, News and Notes - Vol. 34, No. 04

Theology News & Notes was a theological journal published by Fuller Theological Seminary from 1954 through 2014.https://digitalcommons.fuller.edu/tnn/1096/thumbnail.jp

Histomolecular profile of Helicobacter pylori strains circulating in Brazzaville (Congo)

Abstract Background and Aim Helicobacter pylori (Hp) infection is a real public health problem in the Congo. We aimed study the histomolecular profile of Hp strains circulating in Brazzaville, Congo, in order to contribute to the improvement of Hp‐infected patients in the country. Methods This was an analytical‐transversal study carried out from January to November 2020 (i.e. a study period of 11 months) in the endoscopy centers of Brazzaville as well as the molecular biology and anatomopathology laboratories of Pointe‐Noire and Oyo. It involved 100 symptomatic patients over the age of 18 referred for upper GI endoscopy. These patients underwent gastric biopsies for histopathological analysis according to the Sydney classification and molecular analysis using the real‐time polymerase chain reaction (PCR) technique. The frequency of Hp infection was determined using real‐time PCR. PCR was also used to identify the Hp strains and assess their tropism in the gastric mucosa. Digestive symptoms, endoscopic lesions, and histopathological lesions associated with HP infection were studied. Results The incidence of Hp infection was 91%, with a female predominance of 52.75% and an average age of 46.32 years. Endoscopy revealed normal mucosa (56.14%), ulcerated lesions (12.28%), and gastritis (22.81%) in infected patients. Histopathologically, the lesions were chronic atrophic gastritis (91%), with inflammatory activity (16.46%), intestinal metaplasia (16.46%), and adenocarcinoma (3.3%). Cag A strains were present in 85.71% of cases and had no preferential tropism in the gastric mucosa. Strains carrying the Cag A gene were present in severe and serious endoscopic and histopathological lesions. Conclusion The prevalence of Hp infection is 91% in the Brazzaville population. Cag A strains circulate in high proportions and are implicated in the occurrence of severe lesions of the gastric mucosa

Strategy-Proof Mechanism for Obnoxious Facility Location on a Line

LNCS v. 9198 entitled: Computing and Combinatorics: 21st International Conference, COCOON 2015, Beijing, China, August 4-6, 2015, ProceedingsIn the problem of obnoxious facility location, an obnoxious facility is located in an area. To maximize the social welfare, e.g., the sum of distances from all the agents to the facility, we have to get the true locations of each agent. However, each agent may misreport his/her location to stay far away from the obnoxious facility. In this paper, we design strategy-proof mechanisms on locating an obnoxious facility on a real line. Two objective functions, i.e., maximizing the sum of squares of distances (maxSOS) and maximizing the sum of distances (maxSum), have been considered. For maxSOS, a randomized strategy-proof mechanism with approximation ratio 5 / 3 is given, meanwhile the lower bound is proved to be at least 1.042. The lower bound of any randomized strategy-proof mechanisms w.r.t. maxSum is proved to be 1.077. Moreover, an extended model that each agent controls multiple locations is considered. For this model, we investigate deterministic and randomized strategy-proof mechanisms w.r.t. maxSum and maxSOS objectives, respectively. The deterministic mechanisms are shown to be tight for both objectives

Calcium phosphate nanocoatings and nanocomposites, part 2: Thin films for slow drug delivery and osteomyelitis

© 2016 Future Medicine Ltd. During the last two decades although many calcium phosphate based nanomaterials have been proposed for both drug delivery, and bone regeneration, their coating applications have been somehow slow due to the problems related to their complicated synthesis methods. In order to control the efficiency of local drug delivery of a biomaterial the critical pore sizes as well as good control of the chemical composition is pertinent. A variety of calcium phosphate based nanocoated composite drug delivery systems are currently being investigated. This review aims to give an update into the advancements of calcium phosphate nanocoatings and thin film nanolaminates. In particular recent research on PLA/hydroxyapatite composite thin films and coatings into the slow drug delivery for the possible treatment of osteomyelitis is covered