Comparison of step-by-step kinematics of resisted,assisted and unloaded 20-m sprint runs

This investigation examined step-by-step kinematics of sprint running acceleration. Using a randomised counterbalanced approach, 37 female team handball players (age 17.8 ± 1.6 years, body mass 69.6 ± 9.1 kg, height 1.74 ± 0.06 m) performed resisted, assisted and unloaded 20-m sprints within a single session. 20-m sprint times and step velocity, as well as step length, step frequency, contact and flight times of each step were evaluated for each condition with a laser gun and an infrared mat. Almost all measured parameters were altered for each step under the resisted and assisted sprint conditions (η² ≥ 0.28). The exception was step frequency, which did not differ between assisted and normal sprints. Contact time, flight time and step frequency at almost each step were different between ‘fast’ vs. ‘slow’ sub-groups (η² ≥ 0.22). Nevertheless overall both groups responded similarly to the respective sprint conditions. No significant differences in step length were observed between groups for the respective condition. It is possible that continued exposure to assisted sprinting might allow the female team-sports players studied to adapt their coordination to the ‘over-speed’ condition and increase step frequency. It is notable that step-by-step kinematics in these sprints were easy to obtain using relatively inexpensive equipment with possibilities of direct feedback.     

Escalation vs. non-escalation of fan violence in football? Narratives from ultra fans,police officers and security employees

Despite a large body of literature about fan violence issues, research investigating perceptions and dynamics in potentially violent situations, called critical incidents (CIs), is missing. This qualitative study examined the perceptions and dynamics of CIs involving ultra football fans. Fifty-nine semi-structured interviews with individuals (fans, police officers or security employees) involved in eight CIs were conducted and analysed using Interpretative Phenomenological Analysis. The assessment of legitimacy of an out-group’s actions strongly influenced the perception of a CI, which is in line with the Elaborated Social Identity Model. Informative intergroup communication about the own intentions seemed to increase perception of legitimacy, while arrests of fans due to pyrotechnics were perceived by fans as illegitimate. The local fan culture, e.g. the fans’ use of pyrotechnics for their support, is relevant for the understanding of this assessment of legitimacy.     

Interplay between motility and cell-substratum adhesion in amoeboid cells

The effective migration of amoeboid cells requires a fine regulation of cell-substratum adhesion. These entwined processes have been shown to be regulated by a host of biophysical and biochemical cues. Here, we reveal the pivotal role played by calcium-based mechanosensation in the active regulation of adhesion resulting in a high migratory adaptability. Using mechanotactically driven Dictyostelium discoideum amoebae, we uncover the existence of optimal mechanosensitive conditions—corresponding to specific levels of extracellular calcium—for persistent directional migration over physicochemically different substrates. When these optimal mechanosensitive conditions are met, noticeable enhancement in cell migration directionality and speed is achieved, yet with significant differences among the different substrates. In the same narrow range of calcium concentrations that yields optimal cellular mechanosensory activity, we uncovered an absolute minimum in cell-substratum adhesion activity, for all considered substrates, with differences in adhesion strength among them amplified. The blocking of the mechanosensitive ion channels with gadolinium—i.e., the inhibition of the primary mechanosensory apparatus—hampers the active reduction in substrate adhesion, thereby leading to the same undifferentiated and drastically reduced directed migratory response. The adaptive behavioral responses of Dictyostelium cells sensitive to substrates with varying physicochemical properties suggest the possibility of novel surface analyses based on the mechanobiological ability of mechanosensitive and guidable cells to probe substrates at the nanometer-to-micrometer level.     

New Signal Flow Graph Topological Formulas for Linear Active Networks

Topological analysis of the signal flow graph associated with the hybrid system of equations for a linear active or passive electrical network for which the element admittance matrix exists and is diagonal is considered. First, the term cancellation which occurs in Mason's topological formulas is investigated. Necessary and sufficient conditions on the signal flow graph topology such that a term in the expansion of the graph determinant and cofactors either cancels out with another term in the expansion or does not cancel are established. Properties of the associated network which result in non-cancelling terms are given and the number of non-cancelling terms is determined. Second, new signal flow graph topological formulas for the graph determinant and cofactors are proven. These formulas are such that no term cancellation occurs and are readily adaptable to computer implementation. In addition, the number of terms in these formulas is independent of the network tree used to formulate the signal flow graph. Examples are given to illustrate the new formulas.     

Paragons of Virtue: teachers’ conceptual understanding of high ability in an egalitarian school system

Recent research suggests that teachers are useful in identifying high ability, provided they have some advance guidelines on how such identification should be operationalized and why. But how do teachers in an egalitarian school system, with neither specific knowledge nor guidelines, conceptualize and make provision for highly able pupils? A total of 232 teachers, representing all levels of the Swedish comprehensive school system, were questioned on different aspects of their conceptual understanding of talented pupils. Answers were given as brief written statements, and the data submitted to a content analysis which resulted in four cluster matrices. This showed that teachers can identify high ability fairly accurately with regard to cognitive attributes and personality characteristics, but fail to understand the socio‐emotional dynamics. Thus, highly able pupils appeared to have been regarded as ‘paragons of virtue’ possessing the social attributes of the teachers ‘ideal pupil’.     

The gendering of global citizenship: findings from a large-scale quantitative study on global citizenship education experiences

The growing literature on the gendering of citizenship and citizenship education highlights that western notions of ‘citizenship’ have often been framed in a way that implicitly excludes women. At the same time, insofar as feminist writers have addressed citizenship, they have tended to see it in largely local and national terms. While feminist literature has laid the groundwork for understanding how schools have shaped and structured a gendered citizenry, there is a lack of large-scale quantitative data which might allow us to explore the intersection between gender and global citizenship education. Drawing on a large-scale quantitative study on development education/global citizenship education in second-level schools, the data presented here suggest that emergent notions of global citizenship are being gendered in schools. The data suggest that girls’ schools are more likely than other types of schools to emphasise a sense of responsibility for, and an analysis of, global inequalities, while differences also emerge between boys’ schools and co-educational schools.