Background Since 2013, the number of violent crimes and offences by sharp instruments have increased continually, following a previous decrease, with majority of cases occurring among young people and in London. There is limited understanding surrounding the drivers influencing this change in trends, with mostly American-based research identifying risk factors. Methods The aim of this review is to identify and synthesise evidence from a range of literature to identify risk factors associated with weapon-related crime, for young people (aged 10–24 years) within the UK. A search strategy was generated to conduct a systematic search of published and grey literature within four databases (EMBASE, Medline, PsycINFO, and OpenGrey), identifying papers within a UK-context. Abstracts and full texts were screened by two independent reviewers to assess eligibility for inclusion, namely study focus in line with the objectives of the review. Weight of Evidence approach was utilised to assess paper quality, resulting in inclusion of 16 papers. Thematic analysis was conducted for studies to identity and categorise risk factors according to the WHO ecological model. Results No association was found between gender or ethnicity and youth violence, contrasting current understanding shown within media. Multiple research papers identified adverse childhood experiences and poor mental health as positively associated with youth and gang violence. It was suggested that community and societal risk factors, such as discrimination and economic inequality, were frequently linked to youth violence. A small number of studies were included within the review as this is a growing field of research, which may have led to a constrained number of risk factors identified. Due to heterogeneity of studies, a meta-analysis could not be conducted. As many studies displayed positive results, publication bias may be present. Conclusions Several risk factors were identified, with evidence currently heterogeneous with minimal high-quality studies. However, findings highlight key areas for future research, including the link between poor mental health and knife-crime, and the trajectory into gangs. Risk factors should help identify high-risk individuals, targeting them within mitigation strategies to prevent involvement within crime. This should contribute to efforts aimed at reducing the rising crime rates within UK. Systematic review registration number CRD42019138545. Registered at PROSPSERO: 16/08/2019.

This paper is concerned with robust aerodynamic design of compressor blades against erosion. The proposed approach combines a multiobjective genetic algorithm with geometry modeling methods, high-fidelity computational fluid dynamics, and surrogate models to arrive at robust designs on a limited computational budget. The multiobjective formulation used here allows explicit trade-off between the mean and variance of the performance to be carried out. Detailed numerical studies are presented for robust geometric design of a typical compressor fan blade section to illustrate the proposed methodology. The performance of a selected robust optimal solution on the Pareto front is compared to a deterministic optimal solution to demonstrate that significant improvements in the mean shift and variance can be achieved.

SUMMARYIn this paper, we propose an efficient strategy for robust design based on Bayesian Monte Carlo simulation. Robust design is formulated as a multiobjective problem to allow explicit trade-off between the mean performance and variability. The proposed method is applied to a compressor blade design in the presence of manufacturing uncertainty. Process capability data are utilized in conjunction with a parametric geometry model for manufacturing uncertainty quantification. High-fidelity computational fluid dynamics simulations are used to evaluate the aerodynamic performance of the compressor blade. A probabilistic analysis for estimating the effect of manufacturing variations on the aerodynamic performance of the blade is performed and a case for the application of robust design is established. The proposed approach is applied to robust design of compressor blades and a selected design from the final Pareto set is compared with an optimal design obtained by minimizing the nominal performance. The selected robust blade has substantial improvement in robustness against manufacturing variations in comparison with the deterministic optimal blade. Significant savings in computational effort using the proposed method are also illustrated.

SUMMARY The effects of kaolin‐induced hydrocephalus on regional blood‐flow and water content of cat brain and spinal cord were measured. The rôle of the central canal of the spinal cord as an alternative pathway for cerebrospinal fluid in experimental hydrocephalus was also studied by positive contrast ventriculography. In comparison with normal cats, blood‐flow in the cerebrum, cerebellum and brain stem of cats with acute hydrocephalus was reduced by more than 20 per cent: in those with chronic hydrocephalus it was reduced by only 12 per cent. There was an absolute increase of 1 · 5 per cent in water content of the brain in cats with acute hydrocephalus. Water content in the spinal cord was increased by 6 per cent in cats with acute hydrocephalus and by 8 per cent in those with chronic hydrocephalus. When the increased water‐content was taken into account, hydrocephalus caused no significant change in blood‐flow in the cervical, thoracic or lumbar spinal cord. Contrast material perfused through the ventricles of hydrocephalic cats flowed directly into the enlarged central canal of the spinal cord. Kaolin‐induced arachnoiditis completely obstructed communication between the ventricles and the cranial subarachnoid space. The contrast material in the central canal communicated both with the cavities extending into the dorsal columns and with the spinal subarachnoid space. When kaolin was injected directly into the spinal subarachnoid space there was an increase in spinal water‐content, without an enlarged central canal. These results suggest that in addition to kaolin‐induced arachnoiditis, increased intraluminal pressure is necessary to enlarge the central canal. RÉSUMÉ Modifications de la circulation sanguine locale et de la teneur hydrique du cerveau et de la moelle épinière dans l'hydrocéphalie expérimentale aigüe et chronique Les effets de l'hydrocéphalic induite par le kaolin dans la circulation sanguine locale et la teneur hydrique du cerveau et de la moelle épinière de chat ont étéétudiés. Le rôle du canal de l'épendyme comme une voie suppléante pour le liquide céphalo‐rachidien a été aussi étudié. Par comparaison avec des chats normaux la circulation sanguine dans le cerveau, le cervelet et le tronc cérébral des chats présentant une hydrocéphalie aigüe parait réduite de plus de 20 pour cent; la réduction atteint seulement 12 pour cent dans l'hydrocéphalie chronique. Il a été observé une augmentation absolue de 1 · 5 pour cent dans la teneur hydrique du cerveau chez les chats porteurs d'une hydrocéphalie aigue. La teneur hydrique de la moelle épinière était augmentée de six pour cent chez les chats porteurs d'hydrocéphalie aigue et de huit pour cent en cas d'hydrocéphalie chronique. Lorsqu'on tenait compte de cet accroissement de la teneur hydrique, l'hydrocéphalie ne provoquait pas de modifications significatives de la circulation sanguine dans les segments cervicaux, thoraciques et lombaires de la moelle épinière. Un materiel de contraste injecté dans les ventricules des chats hydrocéphales gagnait direct...

The aim of this paper is to develop and illustrate an efficient methodology to design blades with robust aerodynamic performance in the presence of manufacturing uncertainties. A novel geometry parametrization technique is developed to represent manufacturing variations due to tolerancing. A Gaussian Stochastic Process Model is trained using DOE techniques in conjunction with a high fidelity CFD solver. Bayesian Monte Carlo Simulation is then employed to obtain the statistics of the performance at each design point. A multiobjective optimizer is used to search the design space for robust designs. The multiobjective formulation allows explicit trade-off between the mean and variance of the performance. A design, selected from the robust design set is compared with a deterministic optimal design. The results demonstrate an effective method to obtain compressor blade designs which have reduced sensitivity to manufacturing variations with significant savings in computational effort.