College Students’ Values for Self-Expression, their Facebook Use, and Bridging Social Capital

Emerging adults are coming of age in social worlds permeated by social media. Communication with others on social media can provide access to bridging social capital, defined as social resources embedded in relationships with acquaintances which promote access to new information. Grooming ties through self-expression and masspersonal communication in networked publics is important for acquiring bridging social capital, behaviors complicated by context collapse. When engaging in masspersonal communication, social media users must balance their desire to express themselves with their desire to maintain positive impressions to multiple audiences. Recent research suggests an important strategy for navigating context collapse is the use of privacy controls. However, using privacy controls could inhibit relational maintenance with acquaintances who offer novel information. The current study investigates how college students are adapting to masspersonal communication on Facebook by examining their bridging social capital, privacy control behaviors, values for self-expression, and network diversity. Confirming previous research, bridging social capital was associated with frequency of Facebook use and relationship maintenance behaviors, however, it was not associated with privacy control behaviors or network diversity. Value for self-expression, relationship maintenance behaviors, Facebook use, and network size each uniquely predicted bridging social capital. Further, strength of self-expression endorsements differed across masspersonal communication topics. Qualitative analysis of college students’ reasoning about the appropriateness of various masspersonal communication topics provides insights into the values and priorities young people are bringing into their social constructions of online norms in response to new tensions created by context collapse. Implications of findings are discussed

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu