Rollins College

The genusStreptococcuscontains some of the most important commensals and pathogens of the human microbiome. To obtain the fatty acids required for cell membranes,Streptococcuseither produce fatty acidsde novothrough the fatty acid biosynthesis (fab) pathway or uptake host fatty acids through the fatty acid kinase (fak) pathway. Although both thefabandfakpathways represent potential therapeutic targets to prevent or treat infection, progress is limited because of an incomplete understanding of taxon-to-taxon variability in streptococcal lipid metabolism. Here, we examined the role ofde novomonounsaturated fatty acid (MUFA) synthesis in physiology and virulence-associated traits inStreptococcus mutans, Streptococcus pyogenes,andStreptococcus pneumoniae,three major pathogens that cause disease at distinct body sites. In all three species, deletion offabMabolished MUFA production and caused severe growth defects, decreased stress tolerance, increased antibiotic susceptibility, and defects in cell viability, morphology, and division. InS. mutans,loss offabMalso markedly reduced competence signaling and production of the mutacin IV bacteriocin. Deletion offabMincreased susceptibility to killing by human neutrophils inS. mutansandS. pneumoniae,but notS. pyogenes. Together, these findings illustrate that MUFA synthesis is broadly important for streptococcal physiology and cell membrane homeostasis, while its contribution to pathogenesis is strongly species- and context-dependent, providing leads to guide development of novel therapeutic and/or preventative strategies.

ABSTRACT Despite high costs and failure rates, expatriate assignments are a primary tool for multinational enterprises to open new operations and execute strategies in international markets. To investigate this seemingly counterintuitive phenomenon, we utilize a case study approach to examine expatriate assignments through the lens of host country managers (HCM). Most expatriate assignment literature has incorporated perspectives from both expatriate managers and MNE leadership; our work extends existing knowledge by incorporating the voice of HCMs in the expatriate experience—from selection through repatriation. Specifically, this research proposes a holistic expatriate model that highlights HCM value‐adding activities at each stage of the expatriate journey. This research, guided by accepted theories in expatriate assignment literature, also expands existing frameworks to assess expatriate assignments and suggests managerial alternatives to improve expatriate success.

This multi-study project employs structuration theory to examine how social constructions (identities), media structures (algorithms and newsfeeds), and human agency (attitudes and behaviors) shape racial bias on social media. First, a survey of Black users (N = 1,718) reveals 74% report experiencing racial bias on the platforms. Next, an experiment with a diverse participant sample (N = 625) uncovered a significant disconnect between users’ stated preferences for diverse racial justice perspectives and their actual engagement behaviors, which are guided by both implicit and explicit biases. Finally, a field experiment and content analysis (N = 1,600) demonstrates engagement with racial justice content triggers Instagram’s algorithm to systematically exclude cross-cutting posts, effectively segregating users into tribal enclaves. Nevertheless, racial bias persists: Black users remain vulnerable to prejudice and attacks through a variety of interactions, including new connections, algorithmic recommendations, and microaggressions. These findings affirm structuration theory’s core principle that meaning, power, and behavior are co-constructed through ongoing interaction. Even in curated, digital spaces, experiences are continuously negotiated through the recursive interplay of media structures and human agency, reinforcing the persistence of racial bias.

Purpose Scholars were interested in how in-group members perceived news about an out-group. The current study aims to explore the interaction effects of out-group news and comment congruence on news authentication and how the authentication triggers news sharing by considering social media news credibility. Design/methodology/approach The study used an experiment with a 2 (real vs fake news) × 2 (supportive vs opposite comments) factorial design to understand news authentication and follow-up behaviors. Findings The results revealed that the interaction between news types and comment congruency has positive effects on institutional and interpersonal intentional authentication. Supportive comments lead to a higher level of institutional and interpersonal intentional authentication when individuals encounter real news rather than fake news. Interpersonal authentication mediated the effects of comment congruence on news sharing. The effects of comment congruence on interpersonal authentication got stronger among individuals who perceived social media news credibility as lower than high by controlling news credibility. Originality/value The study expands the framework of news authentication by examining the effects of message cues on news behavior, considering the dual influence of hostile media and social credibility assessment. The current study makes a great impact on understanding the misinformation phenomenon and news authentication as a pro-news behavior. The study also provides journalists and news agencies with insights into news practices on social media. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/OIR-03-2024-0204.

Foreign pseudohistory, as one format of conspiracy theories, is an unverified discourse explicitly stating that a culture, civilization, or achievement outside one's homeland country did not exist, does not have historical continuity, or was plagiarized from this homeland country. The current study analyzed 302 videos about foreign pseudohistory from a popular Chinese video-sharing website (Bilibili) and found 213 videos supporting foreign pseudohistory and 89 videos opposing foreign pseudohistory. Videos opposing foreign pseudohistory attract more viewers and comments than videos supporting foreign pseudohistory, but the latter videos are posted by a smaller group of core creators and also attract considerable numbers of views. The inductive thematic analysis identified three major themes from these videos, including: 1) how foreign civilizations and history were based on fabrication and plagiarism; 2) promoting foreign pseudohistory as a way to fight against Western-centrism; and 3) refuting and mocking foreign pseudohistory and enlightening the public about the real history. The implications of this study were discussed.

<title>Abstract</title> This paper proposes a residual tropospheric error modeling methodology for terrestrial radio navigation systems used for civil aviation. The functional scope of this methodology ranges from elevation angles above 0.2° to zenith and aircraft distances up to 250 km. The tropospheric residual error model for aviation applications based on global navigation satellite systems (GNSS) employs a global constant to model only the variance of the zenith tropospheric delay error and is not directly applicable for terrestrial ranging. The proposed model encompasses errors from tropospheric mapping functions, zenith delay models, and atmospheric effects such as ducting. In addition, the residual error model variance is derived to consider the variability of tropospheric delay as a function of elevation angle and aircraft range. For a proposed tropospheric delay compensation model for terrestrial ranging, the resulting residual error model is still conservative and is accurate to 0.74 mm/km for elevation angles down to 0.2°, which will enable terrestrial systems to support increasingly demanding performance-based navigation systems.