In public goods games, individuals contribute to create a benefit for a group. However this attracts free-riders, who enjoy the benefits without necessarily contributing. Nonetheless, in real-life scenarios cooperation does not collapse. Several explanations have been proposed in order to explain this phenomenon, such as punishment and signaling. In the present work, we investigate the effects ...

Over the years of the emergence of peer-to-peer systems a phenomenon named ‘Free Riding’ has affected its performance and become a serious threat to be resolved. Free riding phenomenon was first felt in the study of Gnutella. As the number of free riders increases, the performance of the overall system decreases as free riders use resources without giving anything to the system. To solve the pr...

BACKGROUND All over the world motorcycle accident are one of the major causes of road death and injury. This study aimed to determine the pattern of Motorcycle Fatal Accidents in Mashhad-Iran. METHODS This descriptive cross-sectional study was carried out in 2006 to analyze the epidemiological pattern of the motorcycle accident in Mashhad, North-Eastern Iran. Three hundred fifty cases of moto...

BACKGROUND National estimates of all-terrain vehicle (ATV) riding patterns among youth in the USA are lacking. METHODS We analysed the 2011 YouthStyles survey to estimate the proportion of 12-17 year olds in the USA who had ridden an ATV at least once during the past 12 months and summarise their patterns of helmet use. RESULTS Of the 831 youth respondents, an estimated 25% reported riding ...

Organizations are composed of stable, predominantly cooperative interactions or n-person exchanges. Humans have been engaging in n-person exchanges for a great enough period of evolutionary time that we appear to have evolved a distinct constellation of species-typical mechanisms specialized to solve the adaptive problems posed by this form of social interaction. These mechanisms appear to have...

Motorcycle riders must endure high levels of muscle tension for long periods of time, especially in their arms and forearms, when steering and using handlebar controls. Because the right hand operates the gas handle and front brakes, the present research focuses on fatigue in the right hand flexors. Ten adult riders, aged 32.5±5.5years, volunteered to participate in this study. During the 24h r...

This paper examines differences in accident characteristics and causation at different blood alcohol levels among 372 accident involved motorcycle riders who were tested shortly after they crashed. The subjects were part of a large, prospective, in-depth study of 1082 accident-involved motorcyclists in Thailand in which investigators went to the scene immediately after a crash to collect and an...

BACKGROUND AND OBJECTIVES Successful community-based medical education requires an ongoing relationship among the school, medical students, and community preceptors. The use of medical school faculty as "circuit riders" helps to develop and maintain these relationships. We studied the benefits, challenges, and barriers as seen by faculty participating in circuit riding activities at the Univers...

BitTorrent is undoubtedly the most popular P2P file sharing systems in existence that has been able to attract millions of users. BitTorrent depends on global components for file search, engages a moderator system to guarantee the data integrity of file, and uses an exchange mechanism for file sharing in order to discourage users from free-riding. We conduct one of the largest measurement and a...

Peer-to-peer (P2P) file sharing has become increasingly popular, accounting for as much as 70% of Internet traffic by some estimates. Recently, we have been witnessing the emergence of a new class of popular P2P applications, namely, P2P audio and video streaming. While traditional P2P file distribution applications target elastic data transfers, P2P streaming focuses on the efficient delivery ...