An evolutionary model of the emergence of the media of exchange

Ce travail utilise une version évolutionniste du modèle de Kiyotaki et Wright (1989) sur l'émergence de la monnaie. Le principal objectif de ce travail est d'étudier les conséquences de l'endogénéité du processus d'appariement des agents. Dans ce cas, les conditions de stabilité sont trouvées pour les deux types d'équilibres (équilibre fondamental ou spéculatif). Le second objectif est d'analyser la dynamique hors équilibre quand la distribution des stocks n'est pas supposée avoir sa valeur d'équilibre temporaire. On montre que, pour certain valeurs des paramètres, l'équilibre fondamental et l'équilibre spéculatif sont instables.monnaie;Evolution;Appariement;Dynamique hors équilibre

An evolutionary model of the emergence of the media of exchange

This paper uses an evolutionary version of the commodity money model in Kiyotaki and Wright (1989). The main objective of this paper is to study the implications of endogenizing the matching process. Under the endogenous set up we find stability conditions for each kind of equilibrium (fundamental or speculative). The second objective is to analyse the disequilibrium dynamics, when the inventory distribution is not assumed to be continuously at its temporary equilibrium value. We prove that under this setting, for some values of the parameters the fundamental and speculative states are unstable.Ce travail utilise une version évolutionniste du modèle de Kiyotaki et Wright (1989) sur l'émergence de la monnaie. Le principal objectif de ce travail est d'étudier les conséquences de l'endogénéité du processus d'appariement des agents. Dans ce cas, les conditions de stabilité sont trouvées pour les deux types d'équilibres (équilibre fondamental ou spéculatif). Le second objectif est d'analyser la dynamique hors équilibre quand la distribution des stocks n'est pas supposée avoir sa valeur d'équilibre temporaire. On montre que, pour certain valeurs des paramètres, l'équilibre fondamental et l'équilibre spéculatif sont instables

Evaluation of the relationship between the topographical anatomy in the axillary region of the brachial plexus and the body mass index

WOS: 000439345200023PubMed ID: 28871408To investigate the topographic anatomy of the median, musculocutaneous, radial and ulnar nerves with respect to the axillary artery and to seek whether these configurations are associated with baseline descriptive data including age, gender, and body-mass index. This cross-sectional trial was carried out on 199 patients (85 women, 114 men; average age: 46.78 +/- 15.45 years) in the department of anaesthesiology and reanimation of a tertiary care center. Topographic anatomy of the median, musculocutaneous, radial and ulnar nerves was assessed with ultrasonography. Localization of these nerves with respect to the axillary artery was marked on the map demonstrating 16 zones around the axillary artery. Frequencies of localizations of every nerve in these zones were recorded, and the correlation of these locations with descriptive data including age, gender and BMI was investigated. There was no difference between women and men for the distribution of the median (p = 0.74), ulnar (p = 0.35) and radial (p = 0.64) nerves. However, the musculocutaneous nerve was more commonly located in Zone A13 in men compared to women (p = 0.02). The localization of the median (p = 0.85), ulnar (p = 0.27) and radial (p = 0.88) nerves did not differ remarkably between patients with BMI < 25 kg/m(2) and patients with BMI 25 kg/m(2). Notably, the musculocutaneous nerve was more often determined in Zone A10 in cases with BMI 25 kg/m(2) (p = 0.001). Our results imply that the alignment of the musculocutaneous nerve may vary in men and overweight people. This fact must be considered by the anaesthetist before planning the axillary block of brachial plexus. All these informations may enlighten the planning stages of the brachial plexus blockade

Development of an optimum proliferation medium via the graph kernel statistical analysis method for genetically stable in vitro propagation of endemic Thymus cilicicus (Turkey)

Thymus cilicicus is an endemic Eastern Mediterranean element that has aromatic-medicinal properties. Its natural population spreads across gravelly ground and open rocky areas of South and Southwest Anatolia. The current study on in vitro propagation of T. cilicicus focused deeply on environmental applications such as the development of an optimum medium composition for efficient and genetically stable micropropagation and improved preservation procedures for long-time conservation of elite germplasms for further studies. For this purpose, MS and OM media were used individually and in combination with cytokinins, charcoal, AgNO3, Fe-EDDHA, and H3BO3. The raw data were statistically analyzed via the graph kernel method to optimize the nonlinear relationship between all parameters. The optimal proliferation medium for T. cilicicus was OM supplemented with a combination of 10 g L-1 charcoal and 1 mg L-1 KIN and the calculated averages of the best regeneration rate, the best shoot number and the best shoot length were 96.89%, 3 and 1.24 respectively on this medium. The determination of genetic stability of in vitro grown plants on the optimum medium compositions obtained by the graph kernel method was carried out with the use of the ISSR-PCR technique. All the ISSR primers produced a total of 192 reproductive band profiles, none of which were polymorphic. Furthermore, the micropropagated plants were successfully rooted and acclimatized to greenhouse conditions. In this study, we present a graph kernel multiple propagation index which considers all the possible parameters needing to be analyzed. Such an index is used for the first time for the determination of the optimum proliferation medium

Privacy-preserving collaborative recommendations based on random perturbations

© 2016 Elsevier Ltd Collaborative recommender systems offer a solution to the information overload problem found in online environments such as e-commerce. The use of collaborative filtering, the most widely used recommendation method, gives rise to potential privacy issues. In addition, the user ratings utilized in collaborative filtering systems to recommend products or services must be protected. The purpose of this research is to provide a solution to the privacy concerns of collaborative filtering users, while maintaining high accuracy of recommendations. This paper proposes a multi-level privacy-preserving method for collaborative filtering systems by perturbing each rating before it is submitted to the server. The perturbation method is based on multiple levels and different ranges of random values for each level. Before the submission of each rating, the privacy level and the perturbation range are selected randomly from a fixed range of privacy levels. The proposed privacy method has been experimentally evaluated with the results showing that with a small decrease of utility, user privacy can be protected, while the proposed approach offers practical and effective results

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

Essais en Economie Evolutionniste

This thesis is the study of three evolutionary models. The first model (Chapter 2) is placed in the context of monetary theory, or rather the emergence of money, while the second and third (Chapters 3 and 4) are placed in the context of the theory social choice. In chapters 3 and 4, two models are studied in the context of spatial models of electoral competition.Cette thèse a pour objet l'étude de trois modèles évolutionnistes. Le premier modèle (chapitre 2) se place dans le cadre de la théorie monétaire, ou plus exactement de l'émergence de la monnaie, alors que le deuxième et le troisième (chapitres 3 et 4), se placent dans le cadre de la théorie du choix social. Dans les chapitres 3 et 4, sont étudiés deux modèles dans le cadre des modèles spatiaux de la compétition électorale

Opportunism and the evolution of political competition

We study a unidimensional model of spatial competition between two parties with endogeneous party membership decisions of opportunist candidates. The parties are composed of heterogeneous politicians. There are two types of politicians. The office oriented politicians, referred to as "opportunist" politicians, care only about the spoils of the office. The policy oriented politicians, referred to as "militant" politicians have ideological preferences on the policy space. In this framework, we compare a winner-take-all system, where all the spoils go to the winner, to a proportional system, where the spoils of office are split among the two parties proportionally to their share of the vote. We study the existence of short term political equilibria and then within an evolutionary setup the stability of policies and party membership decisions of opportunist candidates.Cet article étudie la compétition électorale entre deux parties politiques. Les partis s'affrontent sur la base de propositions de politiques dont l'espace est unidimensionnel. Les candidats opportunistes peuvent changer de parti politique et cette décision est endogéneisée. Les partis sont composés de candidats hétérogènes. Il y a deux types de candidats: Les candidats " opportunistes " ont pour seul objectif de remporter les élections ou de maximiser le nombre de voix pour bénéficier du prestige et de la puissance, alors que les candidats " militants " ont des préférences idéologiques. Dans ce cadre, on compare les systèmes politiques majoritaire et proportionnel. On étudie l'existence d'un équilibre de la compétition politique de court terme, puis, dans un contexte évolutionniste, on étudie la décision des candidats opportunistes dans le long terme

Opportunism and the evolution of political competition

Cet article étudie la compétition électorale entre deux parties politiques. Les partis s'affrontent sur la base de propositions de politiques dont l'espace est unidimensionnel. Les candidats opportunistes peuvent changer de parti politique et cette décision est endogéneisée. Les partis sont composés de candidats hétérogènes. Il y a deux types de candidats: Les candidats " opportunistes " ont pour seul objectif de remporter les élections ou de maximiser le nombre de voix pour bénéficier du prestige et de la puissance, alors que les candidats " militants " ont des préférences idéologiques. Dans ce cadre, on compare les systèmes politiques majoritaire et proportionnel. On étudie l'existence d'un équilibre de la compétition politique de court terme, puis, dans un contexte évolutionniste, on étudie la décision des candidats opportunistes dans le long terme.Compétition électorale;Factions;Stabilité