A model balancing cooperation and competition explains our right-handed world and the dominance of left-handed athletes

An overwhelming majority of humans are right-handed. Numerous explanations for individual handedness have been proposed, but this population-level handedness remains puzzling. Here we use a minimal mathematical model to explain this population-level hand preference as an evolved balance between cooperative and competitive pressures in human evolutionary history. We use selection of elite athletes as a test-bed for our evolutionary model and account for the surprising distribution of handedness in many professional sports. Our model predicts strong lateralization in social species with limited combative interaction, and elucidates the rarity of compelling evidence for "pawedness" in the animal world.Comment: 5 pages of text and 3 figures in manuscript, 8 pages of text and two figures in supplementary materia

Commutator Leavitt path algebras

For any field K and directed graph E, we completely describe the elements of the Leavitt path algebra L_K(E) which lie in the commutator subspace [L_K(E),L_K(E)]. We then use this result to classify all Leavitt path algebras L_K(E) that satisfy L_K(E)=[L_K(E),L_K(E)]. We also show that these Leavitt path algebras have the additional (unusual) property that all their Lie ideals are (ring-theoretic) ideals, and construct examples of such rings with various ideal structures.Comment: 24 page

Participatory arts interventions promote interpersonal and intergroup prosocial intentions in middle childhood

We report the results of two experiments which test the potential of arts engagement for promoting prosocial intentions. Experiment 1 (N = 216) tested the impact of a participatory arts intervention (vs. a control condition) on children's empathy and interpersonal prosocial intentions. Experiment 2 (N = 174) tested the impact of a participatory arts intervention (vs. a control condition) on children's prosocial intentions toward outgroup members under competitive and non-competitive conditions. Experiment 1 showed that the participatory arts intervention significantly increased children's interpersonal prosocial intentions, but not their empathy. Experiment 2 showed that, under competitive conditions, the participatory arts intervention significantly increased prosocial intentions toward outgroup members, an effect that persisted for six months beyond the intervention. Under non-competitive conditions, the participatory arts intervention consolidated improvements in prosocial intentions toward outgroup members. Overall, the results confirm the hypothesis that participatory arts engagement can promote prosocial intentions during middle childhood

Nonlinear quantum mechanics implies polynomial-time solution for NP-complete and #P problems

If quantum states exhibit small nonlinearities during time evolution, then quantum computers can be used to solve NP-complete problems in polynomial time. We provide algorithms that solve NP-complete and #P oracle problems by exploiting nonlinear quantum logic gates. It is argued that virtually any deterministic nonlinear quantum theory will include such gates, and the method is explicitly demonstrated using the Weinberg model of nonlinear quantum mechanics.Comment: 10 pages, no figures, submitted to Phys. Rev. Let

Psychological attachment to the group: Cross-cultural differences in organizational identification and subjective norms as predictors of workers' turnover intentions

Two studies wed the theory of reasoned action, social identity theory, and Ashforth and Mael's work on organizational identification to predict turnover intentions in Japanese and British commercial and academic organizations. In both studies and in both countries, the authors expected and found that identification with the organization substantially and significantly predicted turnover intentions. Attitudes predicted intentions only in Study 2, and subjective norms significantly predicted intentions across both studies. The authors hypothesized that subjective norms would be a significantly stronger predictor of turnover intentions in a collectivist setting. This prediction was supported. Although social identity is strongly associated with turnover intentions across both cultures, the subjective normative aspects of group membership are significantly more strongly associated in the Japanese organizations

Ebookness

Since the mid-2000s, the ebook has stabilized into an ontologically distinct form, separate from PDFs and other representations of the book on the screen. The current article delineates the ebook from other emerging digital genres with recourse to the methodologies of platform studies and book history. The ebook is modelled as three concentric circles representing its technological, textual and service infrastructure innovations. This analysis reveals two distinct properties of the ebook: a simulation of the services of the book trade and an emphasis on user textual manipulation. The proposed model is tested with reference to comparative studies of several ebooks published since 2007 and defended against common claims of ebookness about other digital textual genres

Building Bridges with Boats: Preserving Community History through Intra- and Inter-Institutional Collaboration

This chapter discusses Launching through the Surf: The Dory Fleet of Pacific City, a project which documents the historical and contemporary role of dory fishers in the life of the coastal village of Pacific City, Oregon, U.S. Linfield College’s Department of Theatre and Communication Arts, its Jereld R. Nicholson Library, the Pacific City Arts Association, the Pacific City Dorymen\u27s Association, and the Linfield Center for the Northwest joined forces to engage in a collaborative college and community venture to preserve this important facet of Oregon’s history. Using ethnography as a theoretical grounding and oral history as a method, the project utilized artifacts from the dory fleet to augment interview data, and faculty/student teams created a searchable digital archive available via open access. The chapter draws on the authors’ experiences to identify a philosophy of strategic collaboration. Topics include project development and management, assessment, and the role of serendipity. In an era of value-added services where libraries need to continue to prove their worth, partnering with internal and external entities to create content is one way for academic libraries to remain relevant to agencies that do not have direct connections to higher education. This project not only developed a positive “town and gown” relationship with a regional community, it also benefited partner organizations as they sought to fulfill their missions. The project also serves as a potential model for intra- and inter-agency collaboration for all types of libraries

Invertebrate Diet of Breeding and Nonbreeding Crested Caracaras (Caracara cheriway) in Florida

We compared the invertebrate component of the diet of breeding and nonbreeding northern Crested Caracaras (Caracara cheriway) during the breeding season, January through April, in Florida, using pellet analysis. Pellets from breeding adults were collected at active nests and pellets of nonbreeding caracaras were collected from beneath a communal roost. During the breeding season, breeding and nonbreeding caracaras consumed invertebrate prey from a minimum of 61 genera and a total of 33 families from eight orders. Nonbreedingcaracaras consumed greater total numbers of invertebrates, more different prey types, and a greater diversity of invertebrates than did breeding caracaras. Pellets of nonbreeding caracaras contained more invertebrates per pellet, and carrion insects occurred more frequently in pellets of nonbreeding caracaras. Our findings suggest hypotheses regarding the possible role of intraspecific competition in the use of particular habitats and food resources by breeding and nonbreeding caracaras in Florida. Breeding pairs of caracaras are highly territorial and primarily feed nestlings larger-sized vertebrate prey, and field observations indicated that territorial adults can exclude young (nonbreeding) birds from their breeding areas; thus, diet differences may reflect social structure within this population. If pairs of breeding adults exclude conspecifics from important food resources or foraging habitats, nonbreeders may hunt arthropods or rely on carrion by necessity, especially if nonbreeders occur in suboptimal habitat in which other prey are less available

What makes re-finding information difficult? A study of email re-finding

Re-nding information that has been seen or accessed before is a task which can be relatively straight-forward, but often it can be extremely challenging, time-consuming and frustrating. Little is known, however, about what makes one re-finding task harder or easier than another. We performed a user study to learn about the contextual factors that influence users' perception of task diculty in the context of re-finding email messages. 21 participants were issued re-nding tasks to perform on their own personal collections. The participants' responses to questions about the tasks combined with demographic data and collection statistics for the experimental population provide a rich basis to investigate the variables that can influence the perception of diculty. A logistic regression model was developed to examine the relationships be- tween variables and determine whether any factors were associated with perceived task diculty. The model reveals strong relationships between diculty and the time lapsed since a message was read, remembering when the sought-after email was sent, remembering other recipients of the email, the experience of the user and the user's ling strategy. We discuss what these findings mean for the design of re-nding interfaces and future re-finding research