Motives for Using Social Network Sites (SNSs) – An Analysis of SNS Adoption Among Students

Social Network Sites (SNSs) are widely used and have been object of research for some years. Existing studies have investigated single Social Networking (SN) phenomena or the usage of particular SNSs. However, only little research has been conducted on the motives for using SNSs. The paper at hand will present a survey for gaining insight into the motives of SNS usage and potential contextual factors that might shape these moti-ves. The study was conducted in two steps: 1) Generation of hypotheses by guided interviews; 2) Test of hypotheses by two online surveys. Drawing on the results as well as the current body of research, the authors will identify different motives for the usage and none-usage of SNSs and determine potential contextual factors

Social Transactions on Social Network Sites: Can Transaction Cost Theory Contribute to a Better Understanding of Internet Social Networking?

Social Network Sites (SNSs) are a success story by example. User counts as well as page visits have rocketed in recent years. In this paper we propose to utilize Transaction Cost Theory (TCT) and Social Capital Theory (SCT) to make sense of what kind of social interaction is executed on SNSs and why. In doing so we will show how TCT can be applied to SNSs by proposing to include in the theory the construct of social transactions. We will describe the characteristics of social transactions on SNSs as being concerned with the management of Social Capital. We will then determine which social transactions are attracted by SNSs. Finally, wwe discuss how research in the field of Internet Social Networking can benefit from this conceptualisation of social transactions and spell out practical implications

Internet Social Networking

An overview of the literature on Internetsocial networking (ISN) is presented.The authors identify four dominantstreams of research and reviewthe key contributions to the field. Thereview reveals that the research fieldis fragmented and does not yet facilitatea general understanding of thephenomenon. In particular research isvery much skewed towards certain usergroups (e.g., students) and platforms(in particular Facebook). Further, implicationsfor a corporate context arediscussed. In doing so, three contextsof application are differentiated: Socialnetwork sites (SNSs) for 1) recruitingand professional career development,2) relationship facilitation in distributedwork contexts, and 3) interactions withend customers. The authors discussSNS potentials, implications of existingISN research and future research opportunities.In summary, they seek tocontribute to a better understandingof the phenomenon of ISN and to makingavailable the current state of ISN researchfor the wider Enterprise 2.0 community

Disulphide production by Ero1alpha-PDI relay is rapid and effectively regulated

The molecular networks that control endoplasmic reticulum (ER) redox conditions in mammalian cells are incompletely understood. Here, we show that after reductive challenge the ER steady-state disulphide content is restored on a time scale of seconds. Both the oxidase Ero1alpha and the oxidoreductase protein disulphide isomerase (PDI) strongly contribute to the rapid recovery kinetics, but experiments in ERO1-deficient cells indicate the existence of parallel pathways for disulphide generation. We find PDI to be the main substrate of Ero1alpha, and mixed-disulphide complexes of Ero1 primarily form with PDI, to a lesser extent with the PDI-family members ERp57 and ERp72, but are not detectable with another homologue TMX3. We also show for the first time that the oxidation level of PDIs and glutathione is precisely regulated. Apparently, this is achieved neither through ER import of thiols nor by transport of disulphides to the Golgi apparatus. Instead, our data suggest that a dynamic equilibrium between Ero1- and glutathione disulphide-mediated oxidation of PDIs constitutes an important element of ER redox homeostasis

Intention to learn in MMOG: Examining the roles of peer intrinsic and extrinsic motivations

Social Networking Sites (SNS) are one of the most popular business models on the Internet at the moment. At the same time, Social Networking is increasingly interesting as a topic of research in Information Systems. Drawing on existing research in the field, in this paper we propose to distinguish ISN (Internet Social Networking) as a phenomenon from its concrete manifestations in the various SNSs in the marketplace. On the basis of this distinction we take to the classification of SNSs grounded in real-life marketplace variety. In doing so, we identify seven different classes of SNSs. We argue that a typology of SNSs is useful for shaping our understanding of the diverse nature of ISN as existing in concrete manifestations. Most importantly, our classification makes accessible existing research for conceptually sound meta-analysis research. In order to fully grasp the phenomenon of ISN we also propose to include in the definition web sites that feature only certain aspects of ISN, while networking is not their core feature. Using our classification we discuss future research directio

The Mitochondrial Disulfide Relay System: Roles in Oxidative Protein Folding and Beyond

Disulfide bond formation drives protein import of most proteins of the mitochondrial intermembrane space (IMS). The main components of this disulfide relay machinery are the oxidoreductase Mia40 and the sulfhydryl oxidase Erv1/ALR. Their precise functions have been elucidated in molecular detail for the yeast and human enzymes in vitro and in intact cells. However, we still lack knowledge on how Mia40 and Erv1/ALR impact cellular and organism physiology and whether they have functions beyond their role in disulfide bond formation. Here we summarize the principles of oxidation-dependent protein import mediated by the mitochondrial disulfide relay. We proceed by discussing recently described functions of Mia40 in the hypoxia response and of ALR in influencing mitochondrial morphology and its importance for tissue development and embryogenesis. We also include a discussion of the still mysterious function of Erv1/ALR in liver regeneration

Public health significance of chickenpox on ships - conclusions drawn from a case series in the port of Hamburg

Background: Despite international notification requirements, the magnitude of disease transmission on board ships remains undetermined. This case series aims to exemplify that varicella aboard ships is a topic of interest for maritime medicine and of public health significance. Material and methods: Systematic presentation of cases of chickenpox reported to the Hamburg Port Health Authority between November 2007 and April 2008. A systematic literature search on 'ships and chickenpox' was performed. Results: Five crew cases of chickenpox were reported from two passenger ships and two cargo ships. The cases originated from Indonesia (2), the Philippines (1), and Sri Lanka (2). Three cases were notified by the shipmaster, one by a general practitioner, and one by the immigration service. Sources of infection were other crewmembers, passengers, and persons in the home countries. Conclusions: This description of five varicella cases aboard ships points to the significance of the disease among seafarers. Many seafarers originate from tropical countries where seroconversion to varicella zoster virus generally occurs in late adolescents and adults. Thus, a substantial portion of the crew may be non-immune and have the potential to introduce the disease from their home country to the ship, or are at risk for infection on the ship. Port health authorities, shipmasters, and doctors need to be well informed about the relevance of chickenpox on ships and the recommended control measures. Travellers should be advised to report to the ship doctor with any signs of infectious disease. Int Marit Health 2010; 61, 1: 28-3