The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within and on our bodies) as one of the key regulators of gut-brain function and has led to the appreciation of the importance of a distinct microbiota-gut-brain axis. This axis is gaining ever more traction in fields investigating the biological and physiological basis of psychiatric, neurodevelopmental, age-related, and neurodegenerative disorders. The microbiota and the brain communicate with each other via various routes including the immune system, tryptophan metabolism, the vagus nerve and the enteric nervous system, involving microbial metabolites such as short-chain fatty acids, branched chain amino acids, and peptidoglycans. Many factors can influence microbiota composition in early life, including infection, mode of birth delivery, use of antibiotic medications, the nature of nutritional provision, environmental stressors, and host genetics. At the other extreme of life, microbial diversity diminishes with aging. Stress, in particular, can significantly impact the microbiota-gut-brain axis at all stages of life. Much recent work has implicated the gut microbiota in many conditions including autism, anxiety, obesity, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Animal models have been paramount in linking the regulation of fundamental neural processes, such as neurogenesis and myelination, to microbiome activation of microglia. Moreover, translational human studies are ongoing and will greatly enhance the field. Future studies will focus on understanding the mechanisms underlying the microbiota-gut-brain axis and attempt to elucidate microbial-based intervention and therapeutic strategies for neuropsychiatric disorders.

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The present study investigates self-presentation in a nonymous setting and explores differences in self-presentation by distinct ethno-racial groups. Based on content analysis of 83 Facebook profiles of African Americans, Latino, Indian and Vietnamese ancestry students, supplemented by 63 in-person interviews, we found that ethno-racial identities are salient and highly elaborated. The intensive investments of minorities in presenting highly social, culturally explicit and elaborated narratives of self reflect a certain resistance to the racial silencing of minorities by dominant color-blind ideologies of broader society. In the nonymous environment of Facebook, various dimensions of identity claims appear to be grounded in offline realities as revealed in interviews and observations of campus social dynamics.doi:10.1111/j. 1083-6101.2009.01498.x IntroductionMost early studies of the impact of the Internet on identity production focused on online identity constructions in anonymous environments such as MUDs (Multiuser Dungeons), Chat Rooms, and Bulletin Boards (Rheingold, 1995;Surratt, 1998;Turkle, 1995). It was found that individuals tended to play-act at being someone else or act out their underlying negative impulses in the online world. More recently, researchers have shifted their attention to self-presentations in less anonymous online environments such as Internet dating sites Yurchisin, Watchravesringkan, & McCabe, 2005). The nonymity (similar to ''identifiability'') of online environments seems to make people more ''realistic and honest in their self-presentation. Research on nonymous online sites uncovered the display of more affirmative identities reflecting efforts to project a ''hoped for possible'' self, one that is more socially desirable, better than their ''real'' offline identity (Yurchisin et al;Zhao, Grasmuck & Martin, 2008). This research suggested that self-presentations varied according to the nature of the settings: People tend to ''play-act'' at being someone else in anonymous settings and be more ''realistic and honest'' in nonymous environments. The possibility of presenting online identities different from offline expressions creates novel social opportunities for cybernet participants. Yet, identity construction on the Internet is influenced by not only the characteristics of the online environment but also the characteristics of users' social positions including race and ethnicity. Competing identities -racial, gender, sexual, national -are often context specific, mobilized depending on the circumstances. It is thus likely that differing expressions of social identities may interact with distinct online environments. However, most scholarly attention related to the effect of the online environment on the articulation of race has concentrated on anonymous environments. Moreover, many studies that have explored issues of social difference, such as race/ethnicity/gender and the Internet, have focused on the impact of the Internet on offline social dynamics. A contested issue raised in...

Mobile media have become increasingly popular and important in recent years as a means of accessing political information and participating in politics and elections worldwide. However, the emergent field of mobile-focused political participation research requires further definition and development to more clearly address why and how mobile media are producing distinct consequences for political participation. To address this problem, this article uses interdisciplinary insights and a critical review of relevant literature to identify research opportunities that stand to advance mobile political communication theory. Contributions and limitations of studies focused on ICTs and political participation are reviewed and discussed. Analysis of studies focused on the political participation outcomes of mobile media use is synthesized with theory from user-focused mobile communication literature to highlight the unique qualities that distinguish mobile media and the implications of those distinguishing features for studying political participation. Recommendations are made for research directions that would further investigate the association of mobile media’s distinctive features with online and offline forms of political participation. This analysis indicates opportunities for scholars to unpack mobile media’s unique features in ways that potentially redefine political participation, and, accordingly, further the development of research questions and theories that investigate the relationship of mobile media and political participation. It is concluded that research is needed that explains mobile media use in finer detail, accounts for shifting conceptualizations of political participation, and contributes to the development of cross-cultural comparative frameworks.

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This study explores the role of mobile news in democracy by examining individual-level variations in mobile election news use based on demographics, socioeconomic indicators, and mobile media activity breadth, and, in turn, how mobile news use is associated with political participation. Nationally representative data from a random-sample survey of American adults (N = 2,250) in the 2010 general election were analyzed to better explain who mobile election news users are, how they compare to nonusers, and whether mobile news use was associated with voter turnout and mobile campaign donation. Findings underscore the significance of mobile media use and mobile news as phenomena of emerging importance in the election campaigns, and important differential patterns in the relationships of sociodemographics, mobile media, and electoral participation are discussed. By providing a nuanced accounting of the socioeconomic and demographic profile of mobile election news users and how those individuals differ from nonusers, this study enriches explanations of how societal privilege and the benefits of political engagement are related in complicated ways to individual-level variations in consuming and using mobile election news. Notably, for racial minorities, mobile media may provide a bridge across the digital-driven democratic divide and a more effective means of engaging with digital election information than other ICTs. Analysis also extends what is known about how citizens use mobile news to engage with increasingly personalized election campaigns. Results indicate that mobile election news use was a significant positive predictor of the odds of having voted and whether individuals used their mobile devices to make contributions during the campaign. These findings support arguments that the unique qualities of mobile devices are contributing to new and different pathways to political engagement while also retaining significance in relation to traditional forms of offline political participation.

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An MD rater is less likely to differ from a standard established by a consensus of MD ratings than are SP raters rating from recall. If an MD cannot be used, an SP observer is preferable to an SP rating from recall.