A microgravity isolation mount

The design and preliminary testing of a system for isolating microgravity sensitive payloads from spacecraft vibrational and impulsive disturbances is discussed. The Microgravity Isolation Mount (MGIM) concept consists of a platform which floats almost freely within a limited volume inside the spacecraft, but which is constrained to follow the spacecraft in the long term by means of very weak springs. The springs are realized magnetically and form part of a six degree of freedom active magnetic suspension system. The latter operates without any physical contact between the spacecraft and the platform itself. Power and data transfer is also performed by contactless means. Specifications are given for the expected level of input disturbances and the tolerable level of platform acceleration. The structural configuration of the mount is discussed and the design of the principal elements, i.e., actuators, sensors, control loops and power/data transfer devices are described. Finally, the construction of a hardware model that is being used to verify the predicted performance of the MGIM is described

Racism, crisis, Brexit

This article offers a conjunctural analysis of the financial and political crisis within which Brexit occurred with a specific attentiveness to race and racism. Brexit and its aftermath have been overdetermined by racism, including racist violence. We suggest that the Leave campaign secured its victory by bringing together two contradictory but interlocking visions. The first comprises an imperial longing to restore Britain’s place in the world as primus inter pares that occludes any coming to terms with the corrosive legacies of colonial conquest and racist subjugation. The second takes the form of an insular, Powellite narrative of island retreat from a ‘globalising’ world, one that is no longer recognisably ‘British’. Further, the article argues that an invisible driver of the Brexit vote and its racist aftermath has been a politicization of Englishness. We conclude by outlining some resources of hope that could potentially help to negotiate the current emergency

Effect of gamified perceptual learning on visual detection and discrimination skills in equine gait assessment

Background Visual assessment of equine lameness is an everyday veterinary task suffering from poor diagnostic accuracy. The aim of this study was to quantify the impact of the perceptual learning game ‘LamenessTrainer’ on skill development. Methods Thirty‐six undergraduate veterinary students engaged in four game modules teaching the assessment of fore‐ and hindlimb lameness. Computer animations of horses in this game displayed 0% (sound) to 70% (moderately lame) vertical movement asymmetry of head and pelvis. Performance, learning effects, diagnostic accuracy, detection thresholds and survey responses were analysed. Results Following staircase learning, more than 80% of students reliably classified horses with ≥20% asymmetry for forelimb lameness, ≥40% asymmetry for simplified hindlimb lameness and ≥50% asymmetry for realistic hindlimb lameness. During random presentation, on average 82% of sound and 65% of lame horses were assessed correctly during forelimb lameness evaluation, dropping to 39% of sound and 56% of lame horses for hindlimb lameness. Conclusion In less than two hours, systematic perceptual learning through deliberate practice can develop visual assessment skills to an accuracy level comparable to expert assessors scoring the same animations. Skills should be developed further to improve misclassifications of sound and mildly lame horses, especially for hindlimb lameness evaluation

The changing patterns of group politics in Britain

Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate

Iso-osmotic regulation of nitrate accumulation in lettuce (Lactuca sativa L.)

Concerns about possible health hazards arising from human consumption of lettuce and other edible vegetable crops with high concentrations of nitrate have generated demands for a greater understanding of processes involved in its uptake and accumulation in order to devise more sustainable strategies for its control. This paper evaluates a proposed iso-osmotic mechanism for the regulation of nitrate accumulation in lettuce (Lactuca sativa L.) heads. This mechanism assumes that changes in the concentrations of nitrate and all other endogenous osmotica (including anions, cations and neutral solutes) are continually adjusted in tandem to minimise differences in osmotic potential of the shoot sap during growth, with these changes occurring independently of any variations in external water potential. The hypothesis was tested using data from six new experiments, each with a single unique treatment comprising a separate combination of light intensity, N source (nitrate with or without ammonium) and nitrate concentration carried out hydroponically in a glasshouse using a butterhead lettuce variety. Repeat measurements of plant weights and estimates of all of the main soluble constituents (nitrate, potassium, calcium, magnesium, organic anions, chloride, phosphate, sulphate and soluble carbohydrates) in the shoot sap were made at intervals from about 2 weeks after transplanting until commercial maturity, and the data used to calculate changes in average osmotic potential in the shoot. Results showed that nitrate concentrations in the sap increased when average light levels were reduced by between 30 and 49 % and (to a lesser extent) when nitrate was supplied at a supra-optimal concentration, and declined with partial replacement of nitrate by ammonium in the external nutrient supply. The associated changes in the proportions of other endogenous osmotica, in combination with the adjustment of shoot water content, maintained the total solute concentrations in shoot sap approximately constant and minimised differences in osmotic potential between treatments at each sampling date. There was, however, a gradual increase in osmotic potential (ie a decline in total solute concentration) over time largely caused by increases in shoot water content associated with the physiological and morphological development of the plants. Regression analysis using normalised data (to correct for these time trends) showed that the results were consistent with a 1:1 exchange between the concentrations of nitrate and the sum of all other endogenous osmotica throughout growth, providing evidence that an iso-osmotic mechanism (incorporating both concentration and volume regulation) was involved in controlling nitrate concentrations in the shoot

Impacted fetal head during second stage Caesarean birth: A prospective observational study

Objective: To determine the incidence of, and complication rates from, impacted fetal head at full dilatation Caesarean birth in the UK, and record what techniques were used.Design: Prospective observational study using the UK Obstetric Surveillance System (UKOSS).Setting: 159 (82%) of the 194 UK hospitals with obstetric units.Population: All women who underwent second stage Caesarean birth in the UK between 1st March and 31st August 2019. Further information was collected on cases where a dis-impaction technique was used, or the operating surgeon experienced ‘difficulty’ in delivering the head.Methods: Prospective observational study.Main outcome measures: Technique(s) used, maternal and neonatal outcomes.Results: 3,518 s stage Caesarean births reported. The surgeon used a dis-impaction technique or reported ‘difficulty’ in 564 (16%) of these. The most common dis-impaction techniques used were manual elevation of the head by an assistant through the vagina (n = 235) and a fetal “pillow” (n = 176).Thirteen babies (2%) died or sustained severe injury. Four babies died (two directly attributable to the impacted fetal head).Conclusions: Difficulty with delivery of the fetal head and the use of dis-impaction techniques during second stage Caesarean sections are common but there is no consensus as to the best method to achieve delivery and in what order