Plane Decompositions as Tools for Approximation

Tree decompositions were developed by Robertson and Seymour [21]. Since then algorithms have been developed to solve intractable problems efficiently for graphs of bounded tree width. In this paper we extend tree decompositions to allow cycles to exist in the decomposition graph; we call these new decompositions plane decompositions because we require that the decomposition graph be planar. First, we give some background material about tree decompositions and an overview of algorithms both for decompositions and for approximations of planar graphs. Then, we give our plane decomposition definition and an algorithm that uses this decomposition to approximate the size of the maximum independent set of the underlying graph in polynomial time

Student Perspectives of Global Engagement

In this session, we bring students together from the wider Dayton community to discuss their views on global education and their study abroad experiences and to suggest ways in which we might enhance global awareness on campus and the larger community.https://ecommons.udayton.edu/global_voices_5/1007/thumbnail.jp

Need Fulfillment and Stay-Leave Behavior: On the Diagnosticity of Personal and Relational Needs.

Need fulfillment has been found to be associated with numerous positive relationship outcomes, but its impact on stay–leave behavior is less clear. In the current study, we considered whether the fulfillment of different needs might differentially affect stay–leave behavior. We distinguished between needs that are personal in nature and those that are relational in nature. Central to our theoretical analysis is the interdependence-based contention that the fulfillment of different kinds of needs provides diagnostic information regarding a partner’s motives and intentions regarding a relationship. Using two-wave longitudinal data obtained from romantically involved participants, we tested the relative fit of two alternative models that specified the associations between the fulfillment of different kinds of needs, commitment, and stay–leave behavior. Consistent with an interdependence approach, we found that the influence of the fulfillment of personal needs on stay–leave behavior was mediated by commitment, whereas the fulfillment of relational needs directly influenced stay–leave behavior. Implications for relationship functioning are considered

On the Benefits of Valuing Being Friends for Non-Marital Romantic Partners

Romantic relationships are, at their core, friendships. As such, it may be the case that valuing that aspect of the relationship fortifies the romantic relationship against negative outcomes and serves as a buffer against dissolution. We explored the role of valuing friendship within romantic relationships in two two-wave studies examining whether investing in the friendship aspect of the relationship (Study 1; N = 190) and placing importance on affiliative need fulfillment (Study 2; N = 184) were associated with positive concurrent outcomes and positive outcomes over time. Results revealed that valuing the friendship aspect of a romance is a strong positive predictor of concurrent romantic relationship qualities (i.e., love, sexual gratification, and romantic commitment), is associated with increases in these qualities over time and is negatively associated with romantic dissolution. Furthermore, evidence suggests that these benefits come from valuing friendship specifically, rather than any other aspect of the relationship (e.g., the sexual aspect)

One Love: Explicit Monogamy Agreements among Heterosexual Young Adult Couples at Increased Risk of Sexually Transmitted Infections

HIV prevention strategies among couples include condom use, mutual monogamy, and HIV testing. Research suggests that condom use is more likely with new or casual partners, and tends to decline as relationships become steady over time. Little is known, however, about explicit mutual monogamy agreements and HIV testing within heterosexual couples. This study used data from 434 young heterosexual couples at increased risk of HIV and sexually transmitted infections (STIs) to assess (a) couple concordance on perceptions of a monogamy agreement, sustained monogamy, and HIV testing; and (b) the associations of relationship and demographic factors with monogamy agreement, sustained monogamy, and HIV testing. Results indicated only slight to fair agreement within couples on measures of monogamy agreement and sustained monogamy. Overall, 227 couples (52%) concurred that they had an explicit agreement to be monogamous; of those, 162 (71%) had sustained the agreement. Couples with greater health protective communication and commitment were more likely to have a monogamy agreement. Couples of Latino and Hispanic ethnicity and those with children were less likely to have a monogamy agreement. Only commitment was related to sustained monogamy. Having children, greater health protective communication, and perceived vulnerability to HIV and STIs were associated with HIV testing within the couple

Committed to Oprah, Homer, or House: Using the Investment Model to Understand Parasocial Relationships

People can develop close relationships with media figures viewed on TV. Across two studies we examined the extent to which satisfaction with, alternatives to, and investments in such parasocial relationships (PSR) account for feelings of commitment toward favored TV characters. In Study 1, satisfaction and investments positively predicted commitment to fictional TV characters, whereas the alternative of not following any TV character negatively predicted commitment to the PSR. In Study 2, we tested the bases of the investment model as predictors of commitment to fictional (e.g., Homer Simpson) versus nonfictional (e.g., Oprah Winfrey) TV characters. As in Study 1, for both fictional and nonfictional characters, commitment level was significantly predicted by levels of satisfaction and investments. However, the alternative of not following any character was significantly associated with commitment only for fictional characters. Results support the use of the investment model to understand processes underlying PSRs

Similarity in Cigarette Smoking Attracts: A Prospective Study of Romantic Partner Selection by Own Smoking, Smoker Prototype, and Perceived Approval

The current research employs a multi-wave longitudinal design to examine how young adults\u27 own smoking, smoker prototypes, and perceived partner approval of smoking are associated with selection of romantic partners over time. Results indicate that participants who smoke and have a more positive prototype of the typical smoker are more likely to initiate a romantic relationship with someone who smokes and who has greater perceived approval for smoking. The findings suggest the importance of examining romantic partner factors associated with young adult smoking and suggest some important aspects of selection effects in terms of the target of selection (romantic partners), what is selected for (partner smoking and approval), and key participant variables that contribute to selection (participant\u27s own smoking and smoker prototype)

Functional role of PGAM5 multimeric assemblies and their polymerization into filaments.

PGAM5 is a mitochondrial protein phosphatase whose genetic ablation in mice results in mitochondria-related disorders, including neurodegeneration. Functions of PGAM5 include regulation of mitophagy, cell death, metabolism and aging. However, mechanisms regulating PGAM5 activation and signaling are poorly understood. Using electron cryo-microscopy, we show that PGAM5 forms dodecamers in solution. We also present a crystal structure of PGAM5 that reveals the determinants of dodecamer formation. Furthermore, we observe PGAM5 dodecamer assembly into filaments both in vitro and in cells. We find that PGAM5 oligomerization into a dodecamer is not only essential for catalytic activation, but this form also plays a structural role on mitochondrial membranes, which is independent of phosphatase activity. Together, these findings suggest that modulation of the oligomerization of PGAM5 may be a regulatory switch of potential therapeutic interest