Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach

Cooperation is of utmost importance to society as a whole, but is often challenged by individual self-interests. While game theory has studied this problem extensively, there is little work on interactions within and across groups with different preferences or beliefs. Yet, people from different social or cultural backgrounds often meet and interact. This can yield conflict, since behavior that is considered cooperative by one population might be perceived as non-cooperative from the viewpoint of another. To understand the dynamics and outcome of the competitive interactions within and between groups, we study game-dynamical replicator equations for multiple populations with incompatible interests and different power (be this due to different population sizes, material resources, social capital, or other factors). These equations allow us to address various important questions: For example, can cooperation in the prisoner's dilemma be promoted, when two interacting groups have different preferences? Under what conditions can costly punishment, or other mechanisms, foster the evolution of norms? When does cooperation fail, leading to antagonistic behavior, conflict, or even revolutions? And what incentives are needed to reach peaceful agreements between groups with conflicting interests? Our detailed quantitative analysis reveals a large variety of interesting results, which are relevant for society, law and economics, and have implications for the evolution of language and culture as well

Comparison of intra-articular injections of Hyaluronic Acid and Corticosteroid in the treatment of Osteoarthritis of the hip in comparison with intra-articular injections of Bupivacaine. Design of a prospective, randomized, controlled study with blinding of the patients and outcome assessors

<p>Abstract</p> <p>Background</p> <p>Although intra-articular hyaluronic acid is well established as a treatment for osteoarthritis of the knee, its use in hip osteoarthritis is not based on large randomized controlled trials. There is a need for more rigorously designed studies on hip osteoarthritis treatment as this subject is still very much under debate.</p> <p>Methods/Design</p> <p>Randomized, controlled trial with a three-armed, parallel-group design. Approximately 315 patients complying with the inclusion and exclusion criteria will be randomized into one of the following treatment groups: infiltration of the hip joint with hyaluronic acid, with a corticosteroid or with 0.125% bupivacaine.</p> <p>The following outcome measure instruments will be assessed at baseline, i.e. before the intra-articular injection of one of the study products, and then again at six weeks, 3 and 6 months after the initial injection: Pain (100 mm VAS), Harris Hip Score and HOOS, patient assessment of their clinical status (worse, stable or better then at the time of enrollment) and intake of pain rescue medication (number per week). In addition patients will be asked if they have complications/adverse events. The six-month follow-up period for all patients will begin on the date the first injection is administered.</p> <p>Discussion</p> <p>This randomized, controlled, three-arm study will hopefully provide robust information on two of the intra-articular treatments used in hip osteoarthritis, in comparison to bupivacaine.</p> <p>Trial registration</p> <p>NCT01079455</p

The contribution of physician assistants in primary care: a systematic review

The research evidence of the contribution of PAs to primary care was mixed and limited. However, the continued growth in employment of PAs in American primary care suggests that this professional group is judged to be of value by increasing numbers of employers. Further specific studies are needed to fill in the gaps in our knowledge about the effectiveness of PAs' contribution to the international primary care workforce

Total hip replacement rate in a cohort of patients affected by symptomatic hip osteoarthritis following intra-articular sodium hyaluronate (MW 1,500-2,000\ua0kDa) ORTOBRIX study

Hip osteoarthritis is very common and costly. The European League Against Rheumatology Committee agenda asks for research to investigate treatments able to slow down the progression of hip osteoarthritis (OA), to delay joint replacement, and to determine the comparative effectiveness and cost-effectiveness of non-surgical and surgical treatment modalities as well as criteria relating to the indications for and timing of total hip replacement (THR). After publishing the results of a randomized controlled trial and a cohort study on the efficacy of Intra-articular sodium hyaluronate (MW 1,500-2,000\ua0kDa) on symptomatic hip OA, we performed this retrospective study in patients suffering from hip OA treated with ultrasound-guided intra-articular injections of HyalOne (Hyalubrix 60 Italian brand name) involving a group of THR expert orthopedic surgeons to appraise whether or not considered eligible for THR and the frequency and timing of THR. Six orthopedists, not routinely performing hip intra-articular injections, each independently assessed whether 176 patients suffering from hip OA and treated with ultrasound-guided intra-articular injections of sodium hyaluronate (MW 1,500-2,000\ua0kDa) were candidates for THR according to the clinical data (age, body mass index, Pain Visual Analog Scale, Lequesne Algofunctional Index, global patient assessment, global physician assessment, nonsteroidal anti-inflammatory drug intake, and hip X-ray) collected at the first intra-articular sodium hyaluronate injection visit and provided as anonymous electronic data. At 24\ua0months, 159 out of 76 (90\ua0%) patients did not undergo to THR. At 48\ua0months, 82\ua0% (N\u2009=\u2009144) of the study population treated with intra-articular hyaluronic acid avoided THR. In the group of 93 patients considered candidates for THR (that is, in which 4, 5, or 6 orthopedic surgeons agreed that the patient was a suitable candidate for THR), only 17 had undergone THR, with survival results of 82\ua0% at 24\ua0months. At 48\ua0months, this percentage reduced to 66\ua0% in this group. In the other groups of patients (in which respectively 3, 2, 1 or no surgeons were in agreement that the patient was a candidate for THR) arthroplasty is not recorded. Sodium hyaluronate (MW 1,500-2,000\ua0kDa) given by ultrasound-guided injection seems to delay THR in the real context of actual overall management of symptomatic hip OA patients. Although further studies are necessary to confirm these data and to identify outcome predictors, hip viscosupplementation should be considered as conservative treatment to perform before proposing patients for THR