Investigation of angiogenesis genes with anterior cruciate ligament rupture risk in a South African population

The angiogenesis-signalling pathway is a physiological response after mechanical loading to promote matrix remodelling and thereby maintain tissue homeostasis. Studies have shown increased expression of angiogenic molecules in response to loading and in ruptured ligaments. Recently, polymorphisms within the vascular endothelial growth factor A (VEGFA) and kinase insert-domain receptor (KDR) genes were associated with risk of anterior cruciate ligament (ACL) ruptures and Achilles tendinopathy in Caucasian study groups. A case-control genetic association study was conducted on 100 controls and 98 participants with surgically-diagnosed ACL ruptures; of which 51 participants reported non-contact mechanism of injury (NON). All participants were genotyped for five functional polymorphisms: VEGFA (rs699947, rs1570360, rs2010963) and KDR (rs2071559, rs1870377). Haplotypes were inferred. In the male participants, the KDR rs2071559 AG genotype was significantly over-represented (P = 0.048, OR: 1.90, 95% CI: 1.00–3.59) in the controls. Furthermore, the GG genotype was significantly under-represented in the male controls compared to the male ACL group (P = 0.018, OR: 2.77, 95% CI: 1.17–6.55) and the male NON subgroup (P = 0.013, OR: 3.26, 95% CI: 1.24–8.58). Haplotype analysis implicated the KDR gene in all participants and in male participants separately. Collectively, these results implicate the angiogenesis-signalling pathway as a potentially key biological pathway contributing to ACL injury susceptibility.     

The not-so-free agent: Non-performance factors that contribute to free agent compensation premiums

In this study, the authors examine Major League Baseball free agency to identify whether certain factors beyond a player’s on-field performance contribute to contract premiums. These premiums are considered to be the difference between the compensation a player receives in free agency and the marginal revenue product (MRP_t-1) in their contract year. Using 345 free agent transactions over a four-year period (2012–2015), the authors examine the relationships between potential free agent contract premiums and the attributes of a player’s previous team, as well as how contract premiums may be influenced by the level of interest from other teams and certain facets of the acquiring teams. Results suggest that free agents tend to receive compensation premiums when they played for a successful team during their contract year. Playing for a large-market team during their contract year also influenced contract premiums. In addition, free agents tended to realize compensations premiums when multiple teams were bidding for their services, the acquiring teams were in playoff contention the prior year, and the acquiring teams possessed relatively more financial resources. Findings shed additional light on how factors peripheral to a player’s on-field performance may influence the free agency market. Recommendations include that effective control mechanisms are necessary to ensure free agent compensation is commensurate with the value of the player.     

Positivity bias in higher education research

Many forms of bias have been identified in higher education research, and in educational and social research in general. This article identifies a further form of bias, positivity bias, and places it in this broader context. Positivity bias is the tendency, in some forms of published higher education research, to only or chiefly report examples of initiatives or innovations that worked and received positive evaluations. Empirical evidence of positivity bias, in the form of an analysis of a sample of published articles from selected higher education journals, is presented and discussed. Suggestions as to the causes of positivity bias and how it might be handled are presented.