Promising the Future: Virginity Pledges as They Affect Transition to First Intercourse

Since 1993, in response to an organized social movement sponsored by the Southern Baptist Church, well over two and a half million adolescents have taken public "virginity" pledges, in which they promise to abstain from sex until marriage. This paper explores the effect of virginity pledges on the transition to first intercourse. On one hand, we show that adolescents who pledge, controlling for all of the usual characteristics of adolescents and their social contexts that are associated with the transition to sex, are much less likely than adolescents who do not pledge, to have intercourse. The delay effect is substantial and almost impossible to erase. Taking a pledge delays intercourse for a long time. On the other hand, the pledge effect depends on age. Pledging does not work for adolescents at all ages. Second, pledging delays intercourse only in contexts where there are some, but not too many, pledgers. Too few, and too many, pledgers in the adolescent world can negate the pledge effect. The pledge works because it is embedded in an identity movement. Consequently, like other identity movements, the pledge identity is relatively fragile and meaningful only in contexts where it is at least partially non-normative. Consequences of pledging are explored for those who break their promise. Promise breakers are less likely to use contraception at first intercourse

Opposite-Sex Twins and Adolescent Same-Sex Attraction

The authors consider social, genetic, evolutionary, and hormonal transfer hypotheses for same-sex romantic preferences of adolescent (N=5,552) sibling pairs drawn from a nationally representative sample. They show that male but not female opposite-sex twins disproportionately report same-sex attraction; and that the pattern of concordance of same-sex preference among siblings is inconsistent with a simple genetic influence model. Their results provide substantial support for the role of social influences, reject the hormone transfer model, reject a speculative evolutionary theory, and are consistent with a general model that allows for genetic expression of same-sex attraction under specific, highly circumscribed, social conditions

Muscle activation patterns in paralympic and novices hand cycling during incremental test

The few studies on muscle timing in hand cycling are difficult to classify in the motor skill acquirement due to their variety of methods and content. This study aims to replicate two existing studies and thus to extend and connect the current state of research concerning the muscle timing during synchronous pedalling. The activity on- and offset of biceps brachii, triceps brachii, posterior deltoid, anterior deltoid, upper trapezius, and pectoralis major were identified during an incremental test of an elite and three novice athletes. The results showed differences in inter-muscular coordination between the elite and novice hand cyclists. Although the distinction between active and inactive phases was already evident in novice data, the activation pattern of the elite athlete showed an even more precise differentiation between these two phases. These time windows remained stable even with increasing load accompanied only by changes in all signal amplitude, except for deltoid activity, which showed a later onset and offset with increasing load. Thus, in training of hand cyclist novices, the muscle timing concerning the duration and the crank position should be considered. In future studies, the effect of handicap severity and crank frequency must be studied in greater detail

After the Promise: The STD Consequences of Adolescent Virginity Pledges

Understanding the determinants of sexually transmitted disease (STD) acquisition among adolescents and young adults is critical to assess interventions designed to limit the spread of STDs [1, 2, 3]. One set of interventions—adopted by numerous organizations and directly supported by federal policy—are programs that encourage abstinence by encouraging adolescents to make pledges to remain virgins until marriage. This article considers the relationship between adolescent virginity pledges and the sexual behavior of young adults, focusing on STD acquisition

Promising the Future: Virginity Pledges and First Intercourse

Since 1993, in response to a movement sponsored by the Southern Baptist Church, over 2.5 million adolescents have taken public “virginity” pledges, in which they promise to abstain from sex until marriage. This paper explores the effect of those pledges on the transition to first intercourse. Adolescents who pledge are much less likely to have intercourse than adolescents who do not pledge. The delay effect is substantial. On the other hand, the pledge does not work for adolescents at all ages. Second, pledging delays intercourse only in contexts where there are some, but not too many, pledgers. The pledge works because it is embedded in an identity movement. Consequently, the pledge identity is meaningful only in contexts where it is at least partially nonnormative. Consequences of pledging are explored for those who break their promise. Promise breakers are less likely than others to use contraception at first intercourse

Extending Partial Representations of Circle Graphs in Near-Linear Time

The partial representation extension problem generalizes the recognition problem for geometric intersection graphs. The input consists of a graph G, a subgraph $H ⊆ G$ and a representation $\mathcal{R}′$ of H . The question is whether G admits a representation $\mathcal{R}$ whose restriction to H is $\mathcal{R}′$. We study this question for circle graphs, which are intersection graphs of chords of a circle. Their representations are called chord diagrams. We show that for a graph with n vertices and m edges the partial representation extension problem can be solved in $O((n + m)α(n + m))$ time, thereby improving over an $O(n^3)$-time algorithm by Chaplick et al. (J Graph Theory 91(4), 365–394, 2019). The main technical contributions are a canonical way of orienting chord diagrams and a novel compact representation of the set of all canonically oriented chord diagrams that represent a given circle graph G, which is of independent interest

Level-Planarity: Transitivity vs. Even Crossings

The strong Hanani-Tutte theorem states that a graph is planar if and only if it can be drawn such that any two edges that do not share an end cross an even number of times. Fulek et al. (2013, 2016, 2017) have presented Hanani-Tutte results for (radial) level-planarity where the $y$-coordinates (distances to the origin) of the vertices are prescribed. We show that the 2-SAT formulation of level-planarity testing due to Randerath et al. (2001) is equivalent to the strong Hanani-Tutte theorem for level-planarity (2013). By elevating this relationship to radial level planarity, we obtain a novel polynomial-time algorithm for testing radial level-planarity in the spirit of Randerath et al

Extending Partial Representations of Circle Graphs in Near-Linear Time

The partial representation extension problem generalizes the recognition problem for geometric intersection graphs. The input consists of a graph G, a subgraph H ⊆ G and a representation H of H. The question is whether G admits a representation G whose restriction to H is H. We study this question for circle graphs, which are intersection graphs of chords of a circle. Their representations are called chord diagrams. We show that for a graph with n vertices and m edges the partial representation extension problem can be solved in O((n+m)α(n+m)) time, where α is the inverse Ackermann function. This improves over an O(n$^{3}$)-time algorithm by Chaplick, Fulek and Klavík [2019]. The main technical contributions are a canonical way of orienting chord diagrams and a novel compact representation of the set of all canonically oriented chord diagrams that represent a given circle graph G, which is of independent interest

Danmarks udenrigspolitiske udfordringer

Udfordringen for dansk udenrigstjeneste er en flytning fra den atlantiske til den globale og den europæiske søjle. Det er et spørgsmål om rettidig omhu og om at udnytte de muligheder, som EU’s fælles udenrigspolitik giver.&nbsp