Assessing infant carriage systems: ground reaction force implications for gait of the caregiver

Objective: To assess the acute alterations of anterior infant carriage systems on the ground reaction force experienced during over ground walking. Background: Previous research has identified the alterations in posture and gait associated with an increased anterior load (external or internal); however the forces applied to the system due to the altered posture during over ground walking have not been established. Method: Thirteen mixed gender participants completed forty-five over ground walking trials at a self-selected pace under three loaded conditions (unloaded, semi-structured carrier 9.9kg and structured carrier 9.9kg). Each trial consisted of a fifteen metre walkway, centred around a piezoelectric force platform sampling at 1200 Hz. Differences were assessed between loaded and unloaded conditions and across carriers using paired samples t-tests and repeated measures ANOVA. Results: Additional load increased all ground reaction force parameters; however, the magnitude of force changes was influenced by carrier structure. The structured carrier displayed increased force magnitudes, a reduction in the time to vertical maximum heel contact and an increased duration of the flat foot phase in walking gait. Conclusion: Evidence suggest that the acute application of anterior infant carriers alters both kinetic and temporal measures of walking gait. Importantly these changes appear to be governed not solely by the additional mass but also by the structure of the carrier. Application: These findings indicate carrier structure should be considered by the wearer and may be used to inform policy in the recommendation of anterior infant carriage systems use by caregivers

Postural stability is affected in older males with Haemophilia—a matched control study

Despite fall-related injuries having serious consequences for older haemophilic patients, few studies have investigated their postural stability and risk of falls. The aim was to examine postural stability, joint function and joint mobility in haemophiliacs and age-matched controls. Centre of pressure excursions in four 60 s balance conditions, two minute walk test, passive ankle and knee range of motion, Haemophilia Joint Health Score, and Haemophilia Early Arthropathy Detection with Ultrasound score were measured in eight men with haemophilia (people with heamophilia, PWH), and eight age-matched men without haemophilia (people without heamophilia, PWOH). PWH have significantly worse postural stability under physically perturbed conditions (p = 0.001–0.028, η2p = 0.19–0.34), reduced joint function (p = 0.001–0.010, d = 1.33–2.62) and mobility (p < 0.001–0.025, d = 1.01–4.61), and increased centre of pressure (CoP) velocity (p < 0.001–0.003) when compared to PWOH. Postural stability among PWH did not deteriorate with time standing, although significant decreases compared to PWOH across all time intervals were observed (Eyes Open Foam (EOF) CoP ellipse (time x group) p = 0.011, η2p = 0.28; path (time × group) p = 0.035, η2p = 0.21; EOF CoP antero-posterior (AP) (time × group) p = 0.021, η2p = 0.24). Joint function, mobility, and postural stability are reduced in PWH compared to PWOH, driven by differences in the CoP AP range. Dynamic tests incorporating physical perturbation may be more effective than static balance tests on a level surface, and longer period of time to assess postural stability may determine whether fatigue affects ability of PWH to maintain postural stability. Adoption of a possible ‘hip strategy’ by which to achieve balance suggests falls prevention programs need to focus on increasing hip strength and retraining ankle strategy movement to allow PWH to improve balance stability

"Hero Imagery" - Are there performance advantages associated with imagining yourself as your favourite athlete?

Objectives: This study examined whether there are performance advantages associated with a single bout of imagery when imagining yourself ‘as your favourite athlete’, or imagining yourself performing a strength-based task. Design: A blind 2 (Imagery ability: high, low) x 3 (imagery condition: self, “hero”, control) mixed factorial design was used. Methods: Participants (n = 17 male; Mage = 19.7 ± 2.7) completed the Sport Imagery Ability Questionnaire then viewed a standardised video demonstrating the grip strength (GS) task. Three baseline trials separated by one minute were then executed. Three imagery scripts (control, self, hero) were then presented to participants via an MP3 player in a counterbalanced order (an interval of 1-minute was provided between each condition). The conclusion of each imagery script prompted participants to perform the GS task. Performance in each condition was conceptualised as delta change scores (Imagery condition – baseline average). Results: No main effects were present but there was a group x condition interaction (F(2,28) = 4.27, p = .02. ƞ_p^2= .23. The interaction suggests that for individuals with high imagery ability, simply “doing the imagery that they already do” is preferable compared to a scripted self- or hero-imagery condition. For individuals with a low imagery ability, a simple script whether that is self- or hero- based may enhance strength performance, compared to “what they already do”. Conclusion: Imagery ability may influence the effectiveness of a brief imagery intervention. Further examination of processes and outcomes associated with “hero-imagery” is recommended

Absence of Embigin accelerates hearing loss and causes sub-viability, brain and heart defects in C57BL/6N mice due to interaction with Cdh23ᵃʰˡ

Mouse studies continue to help elaborate upon the genetic landscape of mammalian disease and the underlying molecular mechanisms. Here, we have investigated an Embigintm1b allele maintained on a standard C57BL/6N background and on a co-isogenic C57BL/6N background in which the Cdh23ahl allele has been “repaired.” The hypomorphic Cdh23ahl allele is present in several commonly used inbred mouse strains, predisposing them to progressive hearing loss, starting in high-frequency regions. Absence of the neural cell adhesion molecule Embigin on the standard C57BL/6N background leads to accelerated hearing loss and causes sub-viability, brain and cardiac defects. Contrastingly, Embigintm1b/tm1b mice maintained on the co-isogenic “repaired” C57BL/6N background exhibit normal hearing and viability. Thus Embigin genetically interacts with Cdh23. Importantly, our study is the first to demonstrate an effect of the common Cdh23ahl allele outside of the auditory system, which has important ramifications for genetic studies involving inbred strains carrying this allele

Multiplicity dependence of identical particle correlations in the quantum optical approach

Identical particle correlations at fixed multiplicity are consideres in the presence of chaotic and coherent fields. The multiplicity distribution, one-particle momentum density, and two-particle correlation function are obtained based on the diagrammatic representation for cmulants in semi-inclusive events. Our formulation is applied to the analysis of the experimental data on the multiplicity dependence of correlation functions reported by the UA1 and the OPAL Collaborations.Comment: 14 pages, 7 figure

Learning in large learning spaces:the academic engagement of a diverse group of students

Teaching larger groups of students is a growing phenomenon in HE and this brings with it, its own challenges not least for the students themselves but also their lecturers. Demographic factors as well as the experiences that characterise us as individuals will impact upon our ability to learn. The pilot study reported here considered the “academic engagement” of a diverse group of students where their course is delivered in large learning environments. As a pilot study, the paper concludes with the identification of two areas which are worthy of further research. Firstly, the study highlighted that mature students were more likely to engage in learning strategies that are associated with surface learning – the binary opposite to which practitioners often strive to achieve. Secondly, the research suggests that students who appear to know their tutors well indicate a preference for study approaches that are likely to develop deeper learning

‘Not everybody walks around and thinks “That’s an example of othering or stigmatisation”’: identity, pedagogic rights and the acquisition of undergraduate sociology-based social science knowledge

This article places itself in conversation with literature about how the experience and outcomes of university education are structured by intersections between social class, ethnicity, gender, age and type of university attended. It addresses undergraduate students’ acquisition of sociological knowledge in four diverse university settings. Basil Bernstein’s concepts of pedagogic identity, pedagogic rights, classification and framing are employed to analyse curriculum and interviews with 31 students over the period of their undergraduate degree. The nature of a sociology-based disciplinary identity is described and illustrated, and it is shown how the formation of this identity gives access to pedagogic rights and the acquisition of valuable capabilities. Addressing the question of whether pedagogic rights are distributed unequally in a stratified university system, it was found that they were not distributed, as might be expected, according to institutional hierarchy. It is argued that the acquisition of university sociological knowledge can disrupt social inequality

Soil warming alters nitrogen cycling in a New England forest : implications for ecosystem function and structure

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Oecologia 168 (2012): 819-828, doi:10.1007/s00442-011-2133-7.Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease the atmospheric load of greenhouse gases such as carbon dioxide and nitrous oxide. Less well-studied are the effects of climate change on the linkages between soil and plant processes. Here, we report the effects of soil warming on these linkages observed in a large field manipulation of a deciduous forest in southern New England, USA, where soil was continuously warmed 5°C above ambient for 7 years. Over this period, we have observed significant changes to the nitrogen cycle that have the potential to affect tree species composition in the long term. Since the start of the experiment, we have documented a 45% average annual increase in net nitrogen mineralization and a three-fold increase in nitrification such that in years 5 through 7, 25% of the nitrogen mineralized is then nitrified. The warming-induced increase of available nitrogen resulted in increases in the foliar nitrogen content and the relative growth rate of trees in the warmed area. Acer rubrum (red maple) trees have responded the most after 7 years of warming, with the greatest increases in both foliar nitrogen content and relative growth rates. Our study suggests that considering species-specific responses to increases in nitrogen availability and changes in nitrogen form is important in predicting future forest composition and feedbacks to the climate system.This work was supported by the National Institute for Climate Change Research (DOE-DE-FCO2-06-ER64157), DOE BER (DE-SC0005421) and the Harvard Forest Long-Term Ecological Research program (NSF-DEB-0620443)

Age‐related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells

Outer hair cells (OHCs) are electromotile sensory receptors that provide sound amplification within the mammalian cochlea. Although OHCs appear susceptible to ageing, the progression of the pathophysiological changes in these cells is still poorly understood. By using mouse strains with a different progression of hearing loss (C57BL/6J, C57BL/6NTac, C57BL/6NTacCdh23+ , C3H/HeJ), we have identified morphological, physiological and molecular changes in ageing OHCs (9–12 kHz cochlear region). We show that by 6 months of age, OHCs from all strains underwent a reduction in surface area, which was not a sign of degeneration. Although the ageing OHCs retained a normal basolateral membrane protein profile, they showed a reduction in the size of the K+ current and non‐linear capacitance, a readout of prestin‐dependent electromotility. Despite these changes, OHCs have a normal V m and retain the ability to amplify sound, as distortion product otoacoustic emission thresholds were not affected in aged, good‐hearing mice (C3H/HeJ, C57BL/6NTacCdh23+ ). The loss of afferent synapses was present in all strains at 15 months. The number of efferent synapses per OHCs, defined as postsynaptic SK2 puncta, was reduced in aged OHCs of all strains apart from C3H mice. Several of the identified changes occurred in aged OHCs from all mouse strains, thus representing a general trait in the pathophysiological progression of age‐related hearing loss, possibly aimed at preserving functionality. We have also shown that the mechanoelectrical transduction (MET) current from OHCs of mice harbouring the Cdh23ahl allele is reduced with age, highlighting the possibility that changes in the MET apparatus could play a role in cochlear ageing

Structural basis for tunable control of actin dynamics by myosin-15 in mechanosensory stereocilia

The motor protein myosin-15 is necessary for the development and maintenance of mechanosensory stereocilia, and mutations in myosin-15 cause hereditary deafness. In addition to transporting actin regulatory machinery to stereocilia tips, myosin-15 directly nucleates actin filament (“F-actin”) assembly, which is disrupted by a progressive hearing loss mutation (p.D1647G, “jordan”). Here, we present cryo–electron microscopy structures of myosin-15 bound to F-actin, providing a framework for interpreting the impacts of deafness mutations on motor activity and actin nucleation. Rigor myosin-15 evokes conformational changes in F-actin yet maintains flexibility in actin’s D-loop, which mediates inter-subunit contacts, while the jordan mutant locks the D-loop in a single conformation. Adenosine diphosphate–bound myosin-15 also locks the D-loop, which correspondingly blunts actin-polymerization stimulation. We propose myosin-15 enhances polymerization by bridging actin protomers, regulating nucleation efficiency by modulating actin’s structural plasticity in a myosin nucleotide state–dependent manner. This tunable regulation of actin polymerization could be harnessed to precisely control stereocilium height