Over the past few decades, the widespread phenomenon of Internet abuse has gained attention from the public, academia, and the media. In a departure from this negative viewpoint, however, researchers and educators have devoted considerable effort in attempting to understand the influence of online communication on people's psychological well-being. This study focuses specifically on Facebook, and proposes a research model to examine the relationships among Facebook use, online social support, general social support, and psychological well-being. Our results show that using Facebook helped college students to obtain online social support, and that online social support is an extension of general social support. However, although general social support contributes to well-being, online social support appears to have little direct effect on well-being. The relationship between online social support and well-being is mediated through the factor of general social support.

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This study explores trust development and maintenance in temporary, work-oriented virtual teams, and examines the effect of trust on communication and cohesiveness. Results suggest that for work-oriented virtual teams formed on a temporary basis, members swiftly develop calculus-based trust in order to assess the outcomes and costs of maintaining team relationships. Members also rely on prior knowledge to determine other members' competence so that they can make predictions about one another's behaviors. Thus, both calculus-based and knowledge-based trust play accentuating roles in the initial development of work-oriented virtual teams. Identification-based trust also develops swiftly initially, but is relatively insignificant compared to the other two types of trust. Finally, initial trust may correlate to both later communication and later cohesiveness.Key words: work-oriented virtual teams, trust development doi:10.1111/j. 1083-6101.2009.01472.x IntroductionComputer-mediated communication (CMC) technology, such as the Internet, has the potential to overcome spatial and temporal barriers in human communication. CMC systems are sociotechnical systems for supporting such activities as knowledge learning and sharing free from constraints of time and place. Work-oriented virtual teams, composed of parties that have not worked together previously, are becoming the norm in organizations for completing temporary team tasks or project engagements Jarvenpaa, Shaw, & Staples;McKnight, Cummings, & Chervany, 1998). Unlike the traditional teams that are allowed to develop slowly, these teams are required to be effective in completing tasks and meeting various demands from the beginning to the end of the group life. This is especially visible as companies rely more and more on outsourcing in their business operations. In this pursuit, many researchers have focused on understanding the role of trust in influencing the performance of work-oriented virtual teams (Tyler . Trust is ''a state involving confident positive expectations about another's motives with respect to oneself in situations entailing risk '' (Boon & Holmes, 1991, p. 194). For teams in traditionally physical settings, trust has been seen as an essential part of a healthy personality (Erikson, 1997;McKing, Choudhury, & Kacmar, 2002;Shaver & Hazan, 1994), as a foundation for interpersonal relations (Ba & Pavou, 2002;Brown, Poole, & Rodgers, 2004), as a foundation for cooperation (McKnight et al., 1998), and as the basis for stability in social institutions (Aubert & Kelsey, 2003;Larsen & McInerney, 2002;Paul & McDaniel, 2004;Jarvenpaa et al., 2004). 823 &Yet, for temporary, work-oriented virtual teams consisting of members that are geographically dispersed and accountable to different stakeholders, responses often are not synchronized and information exchange can become decoupled from events (Jarvenpaa & Leidner 1998). Hence, there exists much difficulty in monitoring and managing team performance (Chidambaram, 1996;Kollock & Smith, 1996;Paul & McDaniel, 2004;...

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The propagation of magneto-atmospheric waves in an inviscid, compressible and perfectly electrically conducting medium in the presence of a vertical gravitational field and a horizontal magnetic field is investigated. If the medium is isothermal and its magnetic pressure is proportional to its mechanical pressure, it is found that the convective instability arises when the ratio of the Alfvén speed to the sound speed exceeds [2(1 — 1/γ)]½ where γ is the adiabatic index. When the medium is found to be stable, a disturbance in the medium will travel as waves in three different modes. For small wavenumbers, two of these modes are similar to the acoustic and gravity modes found in the nonmagnetic case. For very large wavenumbers, the acoustic mode becomes the modified sound wave found in the case of a uniform medium, while the gravity wave behaves as the corresponding modified hydromagnetic wave unless the component of the wavenumber in the direction of the magnetic lines is sufficiently small. The third mode which does not appear in the nonmagnetic case behaves nearly as a pure hydromagnetic wave; it is influenced only to a minor extent by compressibility and gravity. The damping of each mode due to viscosity, finite electrical and thermal conductivity is discussed.