Relationship between leg stiffness and lower body injuries in professional Australian football

Leg stiffness is a modifiable mechanical property that may be related to soft tissue injury risk. The purpose of this study was to examine mean leg stiffness and bilateral differences in leg stiffness across an entire professional Australian Football League (AFL) season, and determine whether this parameter was related to the incidence of lower body soft tissue injury. The stiffness of the left and right legs of 39 professional AFL players (age 24.4 ± 4.4 years, body mass 87.4 ± 8.1 kg, stature 1.87 ± 0.07 m) was measured using a unilateral hopping test at least once per month throughout the season. Injury data were obtained directly from the head medical officer at the football club. Mean leg stiffness and bilateral differences in leg stiffness were compared between the injured and non-injured players. There was no difference between the season mean leg stiffness values for the injured (219.3 ± 16.1 N x m(-1) x kg(-1)) and non-injured (217.4 ± 14.9 N x m(-1) x kg(-1); P = 0.721) groups. The injured group (7.5 ± 3.0%) recorded a significantly higher season mean bilateral difference in leg stiffness than the non-injured group (5.5 ± 1.3%; P = 0.05). A relatively high bilateral difference in leg stiffness appears to be related to the incidence of soft tissue injury in Australian football players. This information is of particular importance to medical and conditioning staff across a variety of sports.     

The effect of the triple helix system and habitat on regional entrepreneurship: Empirical evidence from the U.S.

The ‘triple helix’ of the university-industry-government relationship and habitat are accepted as important determinants of innovation and entrepreneurship. However, empirical explorations of the effects of these variables and their interrelationships on regional entrepreneurial activities are highly limited. To fill this gap, we investigate the effect of the triple helix system and habitat on birth and death rates of U.S. firms at the state level. As expected, we find that industrial R&D expenditure plays an important role in promoting regional firm birth. However, university and government R&D also generate a synergistic effect that indirectly influences regional firm birth rates. In addition, we find that the synergy between university and industrial R&D enhances the sustainability of firms, while the interactions between (1) university and government R&D and (2) government and industrial R&D are associated with an increase in firm death. Other factors linked to more favorable conditions for firm formation include higher educational attainment in a region, lower tax rate, and habitat factors affecting quality of life, such as lower housing prices and higher rates of health insurance coverage. In regions with high entrepreneurial activity, we find positive synergistic effects of the interactions between (1) university and government R&D and (2) university and industrial R&D on firm birth rate, suggesting that university R&D plays an important role as an ‘entrepreneurial mediator’ among the three spheres in the triple helix system. In low entrepreneurial regions, the only triple helix system factors significantly influencing firm birth rate were tax rate. This finding suggests that the independent and interdependent components of the triple helix system and habitat are less powerful in low entrepreneurial regions.     

Children's reasoning about disclosing adult transgressions: effects of maltreatment, child age, and adult identity

A total of two hundred ninety-nine 4- to 9-year-old maltreated and nonmaltreated children of comparable socioeconomic status and ethnicity judged whether children should or would disclose unspecified transgressions of adults (instigators) to other adults (recipients) in scenarios varying the identity of the instigator (stranger or parent), the identity of the recipient (parent, police, or teacher), and the severity of the transgression ("something really bad" or "something just a little bad"). Children endorsed more disclosure against stranger than parent instigators and less disclosure to teacher than parent and police recipients. The youngest maltreated children endorsed less disclosure than nonmaltreated children, but the opposite was true among the oldest children. Older maltreated children distinguished less than nonmaltreated children between parents and other types of instigators and recipients.     

Personal theory and reflection in a professional practice portfolio

Portfolios are widely used in the assessment of professional learning. Although claims are made that portfolios promote reflection, the nature of such reflection and the mechanisms that promote it in the portfolio process are not well understood. A four‐year action research project investigated a professional practice portfolio for high stakes assessment in a post‐graduate programme for special education resource teachers (RTs) that was preparing them for a paradigmatically different role. This paper focuses on the requirement to submit a personal theory (PT) statement in the portfolio. Although tension between the summative and formative purposes of the portfolio was evident for some RTs, a more comprehensive understanding of reflection was evident and many RTs reported that articulating their PT (often for the first time in their career) impacted positively on their ability to reflect on practice.     

Comparisons among Designs for Equating Mixed-Format Tests in Large-Scale Assessments

In this study we examined variations of the nonequivalent groups equating design for tests containing both multiple-choice (MC) and constructed-response (CR) items to determine which design was most effective in producing equivalent scores across the two tests to be equated. Using data from a large-scale exam, this study investigated the use of anchor CR item rescoring (known as trend scoring) in the context of classical equating methods. Four linking designs were examined: an anchor with only MC items, a mixed-format anchor test containing both MC and CR items; a mixed-format anchor test incorporating common CR item rescoring; and an equivalent groups (EG) design with CR item rescoring, thereby avoiding the need for an anchor test. Designs using either MC items alone or a mixed anchor without CR item rescoring resulted in much larger bias than the other two designs. The EG design with trend scoring resulted in the smallest bias, leading to the smallest root mean squared error value.     

Teaching about ethics through socioscientific issues in physics and chemistry: Teacher candidates' beliefs

The purpose of this qualitative study was to identify and explain the origins of physics and chemistry teacher candidates' beliefs about teaching about ethics through socioscientific issues (SSI). This study utilized a series of in‐depth interviews, while the participants (n = 12) were enrolled in a 9‐month teacher education program at an urban university in Canada. Our data analysis revealed that beliefs about teaching physics and chemistry using SSI derive from a complex web of fundamental beliefs exemplified by four archetypes representing the subject‐specific identities of our teacher candidates—Model Scientist/Engineer, Model Individual, Model Teacher, and Model Citizen. Furthermore, we found that the justification for belief change required by a particular teacher candidate depends on these subject‐discipline identities. Thus, the presence of each archetype in preservice classrooms has ramifications for the way a teacher educator should encourage his or her students to include SSI in their teaching. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 380–401, 2010     

Evaluation of a truancy court intervention in four middle schools

The effectiveness of a school‐based truancy court intervention in four middle schools in a mid‐sized school district was evaluated. Cumulative data from 185 youth attending a truancy court from 2004 through 2008 were included in the analyses. Results indicated a differential impact of the truancy court intervention depending on truancy severity at baseline. The intervention was most successful in increasing attendance for students with severe truancy, but had limited impact on students with moderate truancy, and no impact on mild truancy. The intervention did not result in improved school attachment or grade point averages, nor did it significantly reduce discipline offenses. Furthermore, the aftercare intervention, consisting of regular meetings with an authority figure (e.g., a juvenile officer), was only effective at maintaining truancy court attendance gains for students with severe truancy at baseline, although it was associated with a substantial decrease in discipline offenses for all groups. These results suggest that truancy courts similar to the one described here may have an impact on truancy for severely truant students, but may have a limited effect on students with mild or moderate truancy. © 2009 Wiley Periodicals, Inc.     

Does Children's Academic Achievement Improve when Single Mothers Marry?

Promoting marriage, especially among low-income single mothers with children, is increasingly viewed as a promising public policy strategy for improving developmental outcomes for disadvantaged children. Previous research suggests, however, that children's academic achievement either does not improve or declines when single mothers marry. In this paper, we argue that previous research may understate the benefits of mothers' marriages to children from single-parent families because (1) the short-term and long-term developmental consequences of marriage are not adequately distinguished and (2) child and family contexts in which marriage is likely to confer developmental advantages are not differentiated from those that do not. Using multiple waves of data from the ECLS-K, we find that single mothers' marriages are associated with modest but statistically significant improvements in their children's academic achievement trajectories. However, only children from more advantaged single-parent families benefit from their mothers' marriage.