A systematic search for massive young stars in the Galaxy - the RMS survey

We have selected red MSX sources (RMS) that have the colours of massive young stellar objects (MYSOs). Our aim is to generate a large, systematically selected sample to address questions such as their luminosity function, lifetimes, clustering and triggering. Other objects such as UCHIIs, PN, PPN and AGB stars have similar IR colours and a large programme of ground-based follow-up observations is underway to identify and eliminate these from the sample of the red MSX sources. These include radio continuum observations, kinematic distances, ground-based mid-IR imaging, near-IR imaging and spectroscopy to distinguish. We report the progress of these campaigns on the 3000 candidates, with initial indications showing that a substantial fraction are indeed massive YSOs.Comment: 3 pages, 4 figures Talk in conference: Milky Way surveys, the structure and evolution of our Galaxy, Boston 200

Sagittal plane joint kinetics during stair ascent in patients with peripheral arterial disease and intermittent claudication

Stair negotiation poses a substantial physical demand on the musculoskeletal system and this challenging task can place individuals at risk of falls. Peripheral arterial disease (PAD) can cause intermittent claudication (IC) pain in the calf and results in altered gait mechanics during level walking. However, whether those with PAD-IC adopt alternate strategies to climb stairs is unknown. Twelve participants with PAD-IC (six bilateral and six unilateral) and 10 healthy controls were recruited and instructed to ascend a five-step staircase whilst 3D kinematic data of the lower-limbs were recorded synchronously with kinetic data from force plates embedded into the staircase on steps two and three. Limbs from the unilateral group and both limbs from the bilateral claudicants were categorised as claudicating (N = 18), asymptomatic (N = 6) and control (N = 10). Claudicants walked more slowly than healthy controls (trend; P = < 0.066). Both claudicating- and asymptomatic-limb groups had reduced propulsive GRF (P = 0.025 and P = 0.002, respectively) and vertical GRF (P = 0.005 and P = 0.001, respectively) compared to controls. The claudicating-limb group had a reduced knee extensor moment during forward continuance (P = 0.060), ankle angular velocity at peak moment (P = 0.039) and ankle power generation (P = 0.055) compared to the controls. The slower gait speed, irrespective of laterality of symptoms, indicates functional capacity was determined by the limitations of the claudicating limb. Reduced ankle power generation and angular velocity (despite adequate plantarflexor moment) implies velocity-dependent limitations existed in the calf. The lack of notable compensatory strategies indicates reliance on an impaired muscle group to accomplish this potentially hazardous task, highlighting the importance of maintaining plantarflexor strength and power in those with PAD-IC

Dynamic muscle quality of the plantar flexors is impaired in claudicant patients with peripheral arterial disease and associated with poorer walking endurance

Objectives: Peripheral arterial disease and intermittent claudication (PAD-IC) negatively affects physical activity and function. There is evidence for plantarflexor muscle dysfunction and weakness, however, the extent to which this dysfunction can be attributed to reduced muscle size and/or quality is not yet known. This study investigated whether in vivo plantarflexor muscle quality during static and dynamic contractions are altered by PAD-IC and whether such changes are associated with impaired walking endurance (according to initial and absolute claudication distances). Methods: A total of 22 participants were recruited, consisting of 10 healthy controls and 12 claudicants with occlusion of the superficial femoral artery (seven unilateral and five bilateral). Muscle quality of the combined gastrocnemius muscles during static contractions was calculated by normalising the estimated maximal potential muscle force to the physiological cross-sectional area of both lateral and medial gastrocnemius. Muscle quality during dynamic contractions of the combined plantarflexor muscles was calculated as the ratio of peak voluntary concentric plantarflexor power and the summed volume of lateral and medial gastrocnemius. Results: Dynamic muscle quality was 24% lower in both the claudicating-limb and asymptomatic-limb groups compared to controls (P=.017 and P=.023). The differences were most apparent at the highest contraction velocity (180°/s). Dynamic muscle quality was associated with reduced walking endurance (R=.689, P=.006 and R=.550, P=.042 for initial and absolute claudication distance, respectively). The claudicating-limb group demonstrated a trend towards reduced static muscle quality compared to controls (22%, P=.084). The relative contribution of the soleus muscle to plantarflexion maximum voluntary contraction was significantly higher in both claudicating-limb and asymptomatic-limb groups compared to controls (P=.012 and P=.018). Conclusions: The muscle strength of the plantarflexors in those with PAD-IC appears to be impaired at high contraction velocities. This may be explained by some reduction in gastrocnemii muscle quality and a greater reliance on the prominently type I fibred soleus muscle. The reduced dynamic capability of the plantarflexor muscles was associated with disease severity and walking ability, therefore efforts to improve plantarflexor power through dynamic exercise intervention are vital to maintain functional performance

Interpreting sources of variation in clinical gait analysis: a case study

Objective: To illustrate and discuss sources of gait deviations (experimental, genuine and intentional) during a gait analysis and how these deviations inform clinical decision making. Methods A case study of a 24-year old male diagnosed with Alkaptonuria undergoing a routine gait analysis. A 3D motion capture with the Helen-Hayes marker set was used to quantify lower-limb joint kinematics during barefoot walking along a 10 m walkway at a self-selected pace. Additional 2D video data were recorded in the sagittal and frontal plane. The patient reported no aches or pains in any joint and described his lifestyle as active. Results: Temporal-spatial parameters were within normal ranges for his age and sex. Three sources of gait deviations were identified; the posteriorly rotated pelvis was due to an experimental error and marker misplacement, the increased rotation of the pelvis in the horizontal plane was genuine and observed in both 3D gait curves and in 2D video analysis, finally the inconsistency in knee flexion/extension combined with a seemingly innocuous interest in the consequences of abnormal gait suggested an intentional gait deviation. Conclusions: Gait analysis is an important analytical tool in the management of a variety of conditions that negatively impact on movement. Experienced gait analysts have the ability to recognise genuine gait adaptations that forms part of the decision-making process for that patient. However, their role also necessitates the ability to identify and correct for experimental errors and critically evaluate when a deviation may not be genuine

‘A1: Britain on the Verge’, Art Bermondsey Project Space, London, 16 January 2018 – 20 January 2018

Peter Dench’s recent exhibition at Art Bermondsey Project Space has a contentious title, ‘A1: Britain on the Verge’. Taking its name, on the Verge, from the preface to Paul Graham’s 1983 photobook, A1: The Great North Road, Dench’s project is a study of Britain in the wake of the European Union membership referendum. If Dench’s task, as he implies, is to comprehend the complex and contradictory motives that compelled voters on June 23, 2016, how – if at all – does he achieve this aim? Thirty years on from Graham’s project, how does Dench chart the shifting socio-political and economic landscape in Britain in the referendum’s aftermath? Ultimately, this review argues that Dench’s project is limited by his failure to seriously engage with documentary and its histories

Age related deviation of gait from normality in alkaptonuria.

Alkaptonuria is a rare metabolic disease leading to systemic changes including early and severe arthropathy which affects mobility. Due to unknown reasons, the onset of degenerative changes is delayed to around 30 years of age when both objective and subjective symptoms develop. In order to complement describing the structural changes in alkaptonuria with measures of movement function, clinical gait analysis was added to the list of assessments in 2013. The aim of this study was to describe the deviation of gait from normality as a function of age in patients with alkaptonuria. Three-dimensional movement of reflective markers attached to joints were captured during walking in 39 patients and 10 controls. Subsequent to processing the data to emphasise the shape of marker trajectories, the mean Movement Deviation Profile was generated for all participants. This single number measure gives the deviation of a patient’s gait from a distributed definition of gait normality. Results showed that gait deviation roughly follows a sigmoid profile with minimal increase of gait deviations in a younger patient group and an abrupt large increase around the second half of the 4th decade of life. Larger variations of gait deviations were found in the older group than in the younger group suggesting a complex interaction of multiple factors which determine gait function after symptoms manifest. Continued gait analysis of adults with AKU, extended to younger adults and children with AKU, is expected to complete understanding of both the natural history of alkaptonuria and how interventions can affect movement function

Buzz pollination: studying bee vibrations on flowers

Approximately 6% of flowering plant species possess flowers with anthers that open through small pores or slits. Extracting pollen from this type of specialised flower is achieved most efficiently by vibrating the anthers, a behaviour that has evolved repeatedly among bees. Here I provide a brief overview of studying vibrations produced by bees and their effects on pollen release. I discuss how bee morphology and behaviour affect the mechanical properties of vibrations, and how floral traits may influence the transmission of those vibrations from the bee to the anther, thus mediating pollen release, and ultimately bee and plant fitness. I suggest that understanding the evolution of buzz pollination requires studying the biomechanics of bee vibrations and their transmission on flowers

Influence of stair descent strategies and step height on centre of mass and gait kinetics in the elderly

Age-associated alterations in balance mechanisms and deteriorations in muscle strength may necessitate alternate stair descent strategies to ensure safe negotiation. The aim of the study was to compare the influence of increased step height and stair negotiation strategies; step-over-step (SoS) and step-by-step (SbS) on gait patterns in the elderly. Eleven elderly participants descended a four step custom built instrumented staircase at a self-selected speed. Participants descended using a SoS or SbS strategy on two step configurations: a rise height of 170mm (STD) and a rise height of 255mm (INC). A 3D motion analysis system synchronised with force platforms embedded into the staircase, was used to capture whole body centre of mass (CoM) velocity, acceleration and kinetic data of the leading limb.Compared to STDSoS, STDSbS resulted in reduced CoM vertical (-0.48m/s vs -0.09m/s) and A/P velocity (0.50m/s vs 0.21m/s) during late stance and swing transition with similar reductions in vertical and A/P velocity in INCSoS vs INCSbS (-0.67m/s vs -0.11m/s and 0.49m/s vs 0.23m/s). INCSoS resulted in increased plantarflexor (1.10Nm/kg vs 1.45Nm/kg) and hip extensor moment (-0.08Nm/kg vs 0.43Nm/kg) compared to STDSoS with no differences seen in SbS strategy. An alternate stair descent strategy offers greater CoM control in the potentially dangerous transition between stance and swing. Concurrently, the tandem double stance period negates the need for increased muscle moments in late stance required to eccentrically control the falling body mass in the traditional SoS strategy. SbS could offer increased CoM control and stability during stair descent

Joint moment strategies during stair descent in patients with peripheral arterial disease and intermittent claudication

Objective: To determine the lower limb joint kinetic strategies during stair descent in claudicants with peripheral arterial disease (PAD-IC). Design: Cross-sectional observation study. Setting: University laboratory. Participants: A total of 22 participants; 10 healthy controls and 12 patients diagnosed with PAD-IC. Main Outcome Measures: Between-group comparisons of ground reaction force (GRF) and, hip, knee and ankle kinetics during steady-state stair descent. Results: The claudicating-limb group demonstrated reduced vertical and posterior GRF compared to healthy controls (ES=-1.46 [-2.32,-0.69] and ES=-1.08 [-0.42,-0.26] as well as demonstrating a greater contribution to support moment from the ankle and trends towards a smaller hip contribution (42±14% vs 28±7%, P=.005 and Hip 16±8% vs 21±11%, P=.056, respectively). A unique sub-group was identified within the PAD-IC cohort demonstrating different hip moment strategies during weight acceptance: a novel hip extensor group (PAD-IC HExt) and stereotypical hip flexor group (PAD-IC HFlex). Compared to both healthy controls and the PAD-IC HFlex groups, the PAD-IC HExt group demonstrated increased hip extensor moment (ES=3.05 [1.67,4.42] and ES=3.62 [1.89,5.35]) and reduced knee extensor moment (ES=-2.00 [-3.15,-0.85] and ES=-1.36 [-2.60,-0.11] respectively) during weight acceptance. Conclusions: A novel hip extensor strategy was identified in a sub-group of claudicants which acts to reduce the demand on the knee extensors, but not the plantarflexors. Weakness in the knee extensors may prevent redistribution of the task demand, typically seen in older adults in stair descent, away from the functionally limited plantarflexor muscle group. Further investigation into multi-level joint strength and the relationship to functional tasks is warranted to inform targeted intervention programmes