Lower limb moments differ when towing a weighted sled with different attachment points

Sprinting while towing a sled improves sprinting parameters, however, only kinematic and temporal–spatial variables have been reported. The purpose of this study was to determine how lower extremity joint moment impulses alter when towing a sled compared to normal walking. Twelve participants walked normally, walked while towing a sled with a 50% body weight load attached at the waist, and with a 50% body weight load attached at the shoulders. Joint moment impulses were calculated for the hip, knee, and ankle. A mixed-model ANOVA with a between-subject factor of limb and repeated measures of condition was used to compare differences between limbs and towing conditions for each joint. Towing a sled increased joint moment impulses at the hip, knee, and non-dominant ankle. When compared with normal walking waist attachment increased hip extension moment impulse by 214.5% ( ? 3.31 vs. ? 10.41 Nms/kg), and shoulder attachment increased knee extension moment impulse by 166.9% (4.62 vs. 12.33 Nms/kg). The dominant limb produced greater knee extension moment impulse (p < 0.001), while the non-dominant limb produced greater hip extension (p < 0.001) and ankle plantarflexion moment impulse (p < 0.001) across all conditions. Results suggest that walking while towing may increase hip and knee extension strength.     

Frequency sweep rate dependence on the dielectrophoretic response of polystyrene beads and red blood cells

Alternating current (AC) dielectrophoresis (DEP) experiments for biological particles in microdevices are typically done at a fixed frequency. Reconstructing the DEP response curve from static frequency experiments is laborious, but essential to ascertain differences in dielectric properties of biological particles. Our lab explored the concept of sweeping the frequency as a function of time to rapidly determine the DEP response curve from fewer experiments. For the purpose of determining an ideal sweep rate, homogeneous 6.08 μm polystyrene (PS) beads were used as a model system. Translatability of the sweep rate approach to ∼7 μm red blood cells (RBC) was then verified. An Au/Ti quadrapole electrode microfluidic device was used to separately subject particles and cells to 10Vpp AC electric fields at frequencies ranging from 0.010 to 2.0 MHz over sweep rates from 0.00080 to 0.17 MHz/s. PS beads exhibited negative DEP assembly over the frequencies explored due to Maxwell-Wagner interfacial polarizations. Results demonstrate that frequency sweep rates must be slower than particle polarization timescales to achieve reliable incremental polarizations; sweep rates near 0.00080 MHz/s yielded DEP behaviors very consistent with static frequency DEP responses for both PS beads and RBCs.     

Identifying swimmers as water-polo or swim team-mates from visual displays of less than one second

Abstract

Opportunities for ball passing in water-polo may be brief and the decision to pass only informed by minimal visual input. Since researchers using point light displays have shown that the walking or running gait of familiars can be identified, water-polo players may have the ability to recognize team-mates from their swimming gait. To test this hypothesis, members of a water-polo team and a competition swim team viewed two randomized sets of video clips, each less than one second long, of swimmers from both teams sprinting freestyle past a fixed camera. The arm stroke clip sequence showed only the upper body, and the kick sequence showed only the lower body. After viewing each video clip, observers rated their level of certainty as to whether the swimmer presented was a team-mate or not. Discrimination was significantly above chance in both groups. Water-polo players were better able to identify team-mates from their kick, whereas swimmers were better able to do so by viewing arm stroke. Our results suggest that, as with walking and running gait, small amounts of visual information about swimmers can be used for recognition, and so raise the possibility that specific training may be able to improve team-mate classification in water-polo, particularly in newly formed teams.     

A Game for Christmas? The Argylls,Saxons and Football on the Western Front,December 1914

Historians know that any mention of football and World War I will involve discussions of the Christmas truces of 1914 and the mythical football match between British and German troops. Many British soldiers denied that any truce had occurred let alone a football match. However, while there is indisputable evidence of truces, triangulating proof of football has been elusive. In this paper, a case study of the British 2/Argylls and the German 133/Saxons is developed. The underlying reasons behind the truce are discussed and why some combatants, in the short break from trying to kill each other, probably played football, even though certainly not as the formal match of popular imagination. It is argued that the truce was a result of unique circumstances and was not an overwhelmingly inspirational moment for the majority of troops involved; they all returned to the fighting. Most participants on both sides of the truce probably regarded it as an unexpected holiday and some availed themselves of the opportunity to play their favourite game. The paper concludes by examining recent commemorative events of Christmas 1914 and how they may have contributed to the myth of ‘The Football Match’.     

Toddlers Use the Number Feature in Determiners During Online Noun Comprehension

Function words support many aspects of language acquisition. This study investigated whether toddlers understand the number feature of determiners and use it for noun comprehension. French offers an ideal “test case” as number is phonetically marked in determiners but not in nouns. Twenty French‐learning 24‐month‐olds completed a split‐screen experiment. Looking times to target pictures were measured under 3 trial types varying in the degree to which the determiner matched the number displayed in the object(s). Children looked longer when the determiner matched the object(s), and were confused in trials of clear mismatch. Importantly, their processing resembled that of French adults ( D. Dahan, D. Swingley, M. K. Tanenhaus, & J. S. Magnuson, 2000 ). Thus, children understand the determiner number feature early in acquisition and use this knowledge to constrain online comprehension.     

Self-report measures of the home learning environment in large scale research: Measurement properties and associations with key developmental outcomes

Favourable home learning environments (HLEs) support children’s literacy, numeracy and social development. In large-scale research, HLE is typically measured by self-report survey, but there is little consistency between studies and many different items and latent constructs are observed. Little is known about the stability of these items and constructs over time when used in either longitudinal research or studies with children with a wide range of ages. A review of the literature shows commonalities and differences between approaches in research on HLE. When we tested the psychometric properties of a short-form measure of HLE with a Rasch item-response-model using longitudinal data from over 1600 Australian families, there was support for two dimensions of HLE—formal and informal learning frequency. We found that this measure was stable over the transitional period from pre-K to school as well as between gender and family language background. There were small but significant associations between the HLE measures and cognitive and behavioural developmental outcomes. We recommend that other measures of HLE could be similarly validated to assess their suitability for use in longitudinal research on learning environments. Recommendations are made for the future development of measures of broader constructs of the HLE.     

When Is It Acceptable to Lie? Interpersonal and Intergroup Perspectives on Deception

While deception is generally viewed as an undesirable and unethical action, people evaluate some lies as more detrimental than others. This study examined factors influencing deception assessments, including the seriousness of the lie and whom it benefits. The effect of an intergroup versus an interpersonal context for the lie was examined. Utilizing 24 vignettes varying in terms of these conditions, 259 participants evaluated a lie’s appropriateness, deceptiveness, and complexity. Altruistic and white lies were viewed as less deceptive and more acceptable than self-serving and more consequential lies. Lies evaluated as least acceptable were interpersonal, serious, and self-serving compared to altruistic lies and those embedded in an intergroup context. Intergroup and interpersonal deceptions are recognized as distinct forms of lying and are evaluated differently.     

Into the Unknown: Examining Neural Representations of Parent–Adolescent Interactions

The parent–adolescent relationship is important for adolescents’ emotion regulation (ER), yet little is known regarding the neural patterns of dyadic ER that occur during parent–adolescent interactions. A novel measure that can be used to examine such patterns is cross-brain connectivity (CBC)—concurrent and time-lagged connectivity between two individuals’ brain regions. This study sought to provide evidence of CBC and explore associations between CBC, parenting, and adolescent internalizing symptoms. Thirty-five adolescents (mean age = 15 years, 69% female, 72% Non-Hispanic White, 17% Black, 11% Hispanic or Latino) and one biological parent (94% female) completed an fMRI hyperscanning conflict discussion task. Results revealed CBC between emotion-related brain regions. Exploratory analyses indicated CBC is associated with parenting and adolescent depressive symptoms.