York University

About: York University is a education organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Politics. The organization has 18899 authors who have published 43357 publications receiving 1568560 citations.

Annual age-grouping and athlete development: a meta-analytical review of relative age effects in sport.

Abstract: Annual age-grouping is a common organizational strategy in sport. However, such a strategy appears to promote relative age effects (RAEs). RAEs refer both to the immediate participation and long-term attainment constraints in sport, occurring as a result of chronological age and associated physical (e.g. height) differences as well as selection practices in annual age-grouped cohorts. This article represents the first meta-analytical review of RAEs, aimed to collectively determine (i) the overall prevalence and strength of RAEs across and within sports, and (ii) identify moderator variables. A total of 38 studies, spanning 1984-2007, containing 253 independent samples across 14 sports and 16 countries were re-examined and included in a single analysis using odds ratios and random effects procedures for combining study estimates. Overall results identified consistent prevalence of RAEs, but with small effect sizes. Effect size increased linearly with relative age differences. Follow-up analyses identified age category, skill level and sport context as moderators of RAE magnitude. Sports context involving adolescent (aged 15-18 years) males, at the representative (i.e. regional and national) level in highly popular sports appear most at risk to RAE inequalities. Researchers need to understand the mechanisms by which RAEs magnify and subside, as well as confirm whether RAEs exist in female and more culturally diverse contexts. To reduce and eliminate this social inequality from influencing athletes' experiences, especially within developmental periods, direct policy, organizational and practitioner intervention is required.

Observations of Bullying in the Playground and in the Classroom

Abstract: The present study employed naturalistic observations to compare bullying and victimization in the playground and in the classroom. The results indicated that there were more opportunities to observe aggression and receive and initiate aggression in the playground than in the classroom. The frequency of bullying was higher in the playground (4.5 episodes per hour) than in the classroom (2.4 episodes per hour). The nature of bullying reflected the constraints of the context (i.e. direct bullying was more prevalent in the playground and indirect bullying was more prevalent in the classroom). Being at the receiving end of aggression was more likely to occur in the playground as compared to the classroom. Nonaggressive children were more likely to bully in the playground, whereas aggressive children were more likely to bully in the classroom. There was no difference across context in the proportion of episodes of reinforcement with peers present or in the rate of peer and teacher intervention. The results high...

Why Research in Sustainable Supply Chain Management Should Have No Future

Abstract: In the last two decades the topic of sustainability has moved from the fringes of supply chain management research to the mainstream and is now an area of significant research activity. In this paper we argue that while this increase in acceptance and activity is welcome and has lead to a greater understanding of sustainability, our present knowledge is not sufficient to create truly sustainable supply chains. We build on this insight to identify five main issues that future research needs to address. We argue that when it comes to the theory of sustainable supply chain management, previous research has focused on the synergistic and familiar while overlooking trade-offs and radical innovation. These theoretical issues are compounded by measures that do not truly capture a supply chain’s impacts and methods that are better at looking backwards than forwards. The paper concludes by proposing a series of recommendations that address these issues to help in the development of truly sustainable supply chains.

The tree of eukaryotes

Abstract: Recent advances in resolving the tree of eukaryotes are converging on a model composed of a few large hypothetical 'supergroups', each comprising a diversity of primarily microbial eukaryotes (protists, or protozoa and algae). The process of resolving the tree involves the synthesis of many kinds of data, including single-gene trees, multigene analyses, and other kinds of molecular and structural characters. Here, we review the recent progress in assembling the tree of eukaryotes, describing the major evidence for each supergroup, and where gaps in our knowledge remain. We also consider other factors emerging from phylogenetic analyses and comparative genomics, in particular lateral gene transfer, and whether such factors confound our understanding of the eukaryotic tree.

Uncertainty, Opportunism and Governance: The Effects of Volatility and Ambiguity on Formal and Relational Contracting

Abstract: Volatility and ambiguity are generally thought to create exchange situations more conducive towards opportunism. We examine the effectiveness of contractual and relational governance in constraining opportunism under volatility and ambiguity. We hypothesize that relational contracts will be robust to volatility but not ambiguity, whereas formal contracts will be robust to ambiguity but not volatility. The hypotheses are supported using data from 125 interorganizational relationships involving R&D for new product development. Our findings suggest that formal and relational contracts each may have advantages and disadvantages relative to the other in specific situations, so that they are not simply substitutes. The results have important implications for transaction cost and relational contracting theory, and challenge the view that relational contracts are not so susceptible to opportunism. A revised comparative governance schema is theorized for future research.