Contact based void partitioning to assess filtration properties in DEM simulations

Discrete element method (DEM) simulations model the behaviour of a granular material by explicitly considering the individual particles. In principle, DEM analyses then provide a means to relate particle scale mechanisms with the overall, macro-scale response. However, interpretative algorithms must be applied to gain useful scientific insight using the very large amount of data available from DEM simulations. The particle and contact coordinates as well as the contact orientations can be directly obtained from a DEM simulation and the application of measures such as the coordination number and the fabric tensor to describe these data is now well-established. However, a granular material has two phases and a full description of the material also requires consideration of the voids. Quantitative analysis of the void space can give further insight into directional fabric and is also useful in assessing the filtration characteristics of a granular material. The void topology is not directly given by the DEM simulation data; rather it must be inferred from the geometry of particle phase. The current study considers the use of the contact coordinates to partition the void space for 3D DEM simulation datasets and to define individual voids as well as the boundaries or constrictions between the voids. The measured constriction sizes are comparable to those calculated using Delaunay-triangulation based methods, and the contact-based method has the advantage of being less subjective. In an example application, the method was applied to DEM models of reservoir sandstones to establish the relationship between particle and constriction sizes as well as the relationship between the void topology and the coordination number and the evolution of these properties during shearing

Using DEM to assess the influence of stress and fabric inhomogeneity and anisotropy on susceptibility to suffusion

Underfilled and gap-graded soils are known to be susceptible to suffusion; a form of internal instability in which the finer fraction of a soil is washed out from the coarser matrix under the action of seepage. This phenomenon poses a risk to embankment dams and flood embankments. The processes and mechanisms operate at the particle scale, and insight can be gained via the particulate discrete element method (DEM). Vir-tual samples can be created using DEM and simulation results can provide information on particle stresses, as well as quantitative information on the fabric of the particulate material. This is important as the amount of stress carried by the finer particles is thought to govern the susceptibility of a given material to suffusion. DEM modelling can also provide information on variation in properties within samples as well as the detailed data needed to quantify the material fabric. DEM models are, however, an idealization of reality and con-strained in particular by the number of particles used and sample preparation method. This study examines key issues relating to the development of virtual samples for use in DEM analysis and also examines the proportion of the applied stress that is carried by the finer particles

Study on the gender dimension of trafficking in human beings

The purpose of this study is to contribute to the identification and understanding of what it means to be ‘taking into account the gender perspective, to strengthen the prevention of this crime and protection of the victims there-of’, as required in Article 1 of European Union (EU) Directive 2011/36/EU on Preventing and Combating Trafficking in Human Beings and Protecting its Victims in the context of the EU Strategy (COM(2012) 286 final) Towards the Eradication of Trafficking in Human Beings. The study contributes to Priority E Action 2 of the Strategy, which states that ‘the Commission will develop knowledge on the gender dimensions of human trafficking, including the gender consequences of the various forms of trafficking and potential differences in the vulnerability of men and women to victimisation and its impact on them.’ Its specific objectives and tasks are to address: the ‘gender dimension of vulnerability, recruitment, and victimisation’; ‘gender issues related to traffickers and to those creating demand’; and ‘an examination of law and policy responses on trafficking in human beings from a gender perspective’. The study addresses the five priorities of the EU Strategy: identifying, protecting, and assisting victims of traf-ficking; stepping up the prevention of trafficking in human beings; better law enforcement; enhanced coordination and cooperation among key actors and policy coherence; and increased knowledge of an effective response to emerging concerns. This study, according to its terms of reference, aims to look specifically at the gender dimension of trafficking for the purpose of sexual exploitation. This follows evidence from statistical data from Eurostat, as well as da-ta from The European Police Office (Europol) and the United Nations Office on Drugs and Crime (UNODC), accord-ing to which the most reported form of exploitation of victims is that of sexual exploitation and its strong gen-der dimension (96 % women and girls). It further addresses recommendations addressed in the Resolution of the European Parliament of 26 February 2014 on sexual exploitation and prostitution and its impact on gender equality (2013/2103(INI)) urging the European Commission to evaluate the impact that the European legal frame-work designed to eliminate trafficking for sexual exploitation has had to date and to undertake further research on patterns of prostitution, on human trafficking for the purpose of sexual exploitation and on the increased lev-el of sex tourism in the EU, with particular reference to minors, and to promote the exchange of best practices among the Member States. The study identifies and draws on EU law and policy competence in gender equality in its identification of the gen-der dimensions of trafficking. The gender dimensions are clustered into five issues: gender specificity and equal treatment; gender expertise, gender balance in decision-making and gender mainstreaming; the relationship be-tween prostitution and trafficking; gendered policy fields and strategic priorities; gendered systems and the the-ory of prevention

Robot guided 'pen skill' training in children with motor difficulties

Motor deficits are linked to a range of negative physical, social and academic consequences. Haptic robotic interventions, based on the principles of sensorimotor learning, have been shown previously to help children with motor problems learn new movements. We therefore examined whether the training benefits of a robotic system would generalise to a standardised test of 'pen-skills', assessed using objective kinematic measures [via the Clinical Kinematic Assessment Tool, CKAT]. A counterbalanced, cross-over design was used in a group of 51 children (37 male, aged 5-11 years) with manual control difficulties. Improved performance on a novel task using the robotic device could be attributed to the intervention but there was no evidence of generalisation to any of the CKAT tasks. The robotic system appears to have the potential to support motor learning, with the technology affording numerous advantages. However, the training regime may need to target particular manual skills (e.g. letter formation) in order to obtain clinically significant improvements in specific skills such as handwriting.</p

Starting School: a large-scale start of school assessment within the ‘Born in Bradford’ longitudinal cohort [version 1; peer review: 1 approved with reservations]

The Born in Bradford (BiB) cohort of 13,776 children born between 2007-2011 and their parents provides a rich data resource for researchers exploring protective and risk factors influencing long-term developmental and health outcomes. Educational attainment is a critical factor related to later health. Literacy and communication, fine motor skills and social and emotional health are key ‘early’ predictors of educational attainment and can be used to identify children in need of additional support. We describe our BiB ‘Starting School’ data collection protocol which assessed literacy and communication, fine motor skills and social and emotional health on 3,444 BiB children aged 4-5 years old. These measures supplement the existing dataset, and complement the routine educational, health and social care data available for the cohort

Large-scale assessment of 7-11-year-olds’ cognitive and sensorimotor function within the Born in Bradford longitudinal birth cohort study [version 2; peer review: 3 approved, 1 approved with reservations]

Background: Cognitive ability and sensorimotor function are crucial aspects of children’s development, and are associated with physical and mental health outcomes and educational attainment. This paper describes cross-sectional sensorimotor and cognitive function data collected on over 15,000 children aged 7-10 years, collected as part of the Born in Bradford (BiB) longitudinal birth-cohort study. Methodological details of the large-scale data collection process are described, along with initial analyses of the data involving the relationship between cognition/sensorimotor ability and age and task difficulty, and associations between tasks. Method: Data collection was completed in 86 schools between May 2016 and July 2019. Children were tested at school, individually, using a tablet computer with a digital stylus or finger touch for input. Assessments comprised a battery of three sensorimotor tasks (Tracking, Aiming, & Steering) and five cognitive tasks (three Working Memory tasks, Inhibition, and Processing Speed), which took approximately 40 minutes. Results: Performance improved with increasing age and decreasing task difficulty, for each task. Performance on all three sensorimotor tasks was correlated, as was performance on the three working memory tasks. In addition, performance on a composite working memory score correlated with performance on both inhibition and processing speed. Interestingly, within age-group variation was much larger than between age-group variation. Conclusions: The current project collected computerised measures of a range of cognitive and sensorimotor functions at 7-10 years of age in over 15,000 children. Performance varied as expected by age and task difficulty, and showed the predicted correlations between related tasks. Large within-age group variation highlights the need to consider the profile of individual children in studying cognitive and sensorimotor development. These data can be linked to the wider BiB dataset including measures of physical and mental health, biomarkers and genome-wide data, socio-demographic information, and routine data from local health and education services