Stability of hexagonal solidification patterns

We investigate the dynamics of cellular solidification patterns using three-dimensional phase-field simulations. The cells can organize into stable hexagonal patterns or exhibit unsteady evolutions. We identify the relevant secondary instabilities of regular hexagonal arrays and find that the stability boundaries depend significantly on the strength of crystalline anisotropy. We also find multiplet states that can be reached by applying well-defined perturbations to a pre-existing hexagonal array.Comment: Minor changes, mainly in introduction and conclusion, one reference adde

Multi-physics ensemble snow modelling in the western Himalaya

Combining multiple data sources with multi-physics simulation frameworks offers new potential to extend snow model inter-comparison efforts to the Himalaya. As such, this study evaluates the sensitivity of simulated regional snow cover and runoff dynamics to different snowpack process representations. The evaluation is based on a spatially distributed version of the Factorial Snowpack Model (FSM) set up for the Astore catchment in the upper Indus basin. The FSM multi-physics model was driven by climate fields from the High Asia Refined Analysis (HAR) dynamical downscaling product. Ensemble performance was evaluated primarily using MODIS remote sensing of snow-covered area, albedo and land surface temperature. In line with previous snow model inter-comparisons, no single FSM configuration performs best in all of the years simulated. However, the results demonstrate that performance variation in this case is at least partly related to inaccuracies in the sequencing of inter-annual variation in HAR climate inputs, not just FSM model limitations. Ensemble spread is dominated by interactions between parameterisations of albedo, snowpack hydrology and atmospheric stability effects on turbulent heat fluxes. The resulting ensemble structure is similar in different years, which leads to systematic divergence in ablation and mass balance at high elevations. While ensemble spread and errors are notably lower when viewed as anomalies, FSM configurations show important differences in their absolute sensitivity to climate variation. Comparison with observations suggests that a subset of the ensemble should be retained for climate change projections, namely those members including prognostic albedo and liquid water retention, refreezing and drainage processes

Cultural basis of social ‘deficits’ in autism spectrum disorders

There is very little research that specifically looks at how autism spectrum disorders are perceived in various communities. This qualitative research was conducted with parents who had children on the autistic spectrum belonging to four different ethnic communities (White British, Somali, West African and South Asian- 63 in total) and living in the UK. The study found that the importance that the parents give to various social skills varied on the basis of their cultural background and the gender of the parent. This is an important aspect to consider while providing support and services to individuals on the autism spectrum and their family members if the services have to be appropriate for their needs. This consideration would also enable the individuals on the autism spectrum to develop appropriate social skills required within their cultural groups. This is a preliminary study and further research on the topic is required

Dairy cows value an open area for lying down

As dairy cows are being housed for longer periods, with all-year-round housing growing in popularity, it is important to ensure housed environments are meeting the needs of cows. Dairy cows are motivated to access open lying areas, although previous motivation studies on this topic have confounded surface type and location (i.e. pasture outdoors vs cubicles indoors). This study measured cow motivation for lying down on an indoor open mattress (MAT; 9 m x 5 m) compared to indoor mattress-bedded cubicles, thus removing the confounding factor of surface type and location. This was repeated for an identically sized indoor deep-bedded straw yard (ST), to investigate whether surface type affected motivation for an open lying area. Thirty Holstein-Friesian dairy cows were housed in groups of 5 (n = 5 x 6) in an indoor robotic milking unit with access to six mattress-bedded cubicles. To assess motivation, cows were required to walk increasing distances via a one-way indoor raceway to access the open lying areas: Short (34.5 m), followed by Medium (80.5 m) and Long (126.5 m). Cows could choose to walk the raceway, leading to the MAT or ST, to lie down or they could lie down on the cubicles for ‘free’. Overall, cows lay down for longer on the open lying areas at each distance compared to the cubicles, with cows lying down slightly longer on ST than MAT, although lying times on the open lying areas did decrease at the Long distance. However, cows were still lying for >60% of their lying time on the open lying areas at the Long distance. This study demonstrates that cows had a high motivation for an open lying area, the provision of which could better cater for the behavioural needs of housed dairy cows and improve housed dairy cow welfare

A new polymorphic material? Structural degeneracy of ZrMn_2

Based on density functional calculations, we propose that ZrMn_2 is a polymorphic material. We predict that at low temperatures the cubic C15, and the hexagonal C14 and C36 structures of the Laves phase compound ZrMn_2 are nearly equally stable within 0.3 kJmol^{-1} or 30 K. This degeneracy occurs when the Mn atoms magnetize spontaneously in a ferromagnetic arrangement forming the states of lowest energy. From the temperature dependent free energies at T approx 160K we predict a transition from the most stable C15 to the C14 structure, which is the experimentally observed structure at elevated temperatures.Comment: 4 pages, 3 figure

Measuring commissioners’ willingness-to-pay for community based childhood obesity prevention programmes using a discrete choice experiment

Background: In the UK, rates of childhood obesity remain high. Community based programmes for child obesity prevention are available to be commissioned by local authorities. However, there is a lack of evidence regarding how programmes are commissioned and which attributes of programmes are valued most by commissioners. The aim of this study was to determine the factors that decision-makers prioritise when commissioning programmes that target childhood obesity prevention. Methods: An online discrete choice experiment (DCE) was used to survey commissioners and decision makers in the UK to assess their willingness-to-pay for childhood obesity programmes. Results: A total of 64 commissioners and other decision makers completed the DCE. The impact of programmes on behavioural outcomes was prioritised, with participants willing to pay an extra £16,600/year if average daily fruit and vegetable intake increased for each child by one additional portion. Participants also prioritised programmes that had greater number of parents fully completing them, and were willing to pay an extra £4810/year for every additional parent completing a programme. The number of parents enrolling in a programme (holding the number completing fixed) and hours of staff time required did not significantly influence choices. Conclusions: Emphasis on high programme completion rates and success increasing children’s fruit and vegetable intake has potential to increase commissioning of community based obesity prevention programmes