527 research outputs found
Risk factors associated with knife-crime in United Kingdom among young people aged 10-24âyears: a systematic review
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 10-24âyears) 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
A comparison of statistical emulation methodologies for multi-wave calibration of environmental models
Expensive computer codes, particularly those used simulating environmental or geological processes such as climate models, require calibration (sometimes called tuning). When calibrating expensive simulators using uncertainty quantification methods, it is usually necessary to use a statistical model called an emulator in place of the computer code when running the calibration algorithm. Though emulators based on Gaussian processes are typically many orders of magnitude faster to evaluate than the simulator they mimic, many applications have sought to speed up the computations by using regression-only emulators within the calculations instead, arguing that the extra sophistication brought using the Gaussian process is not worth the extra computational power. This was the case for the analysis that produced the UK climate projections in 2009. In this paper we compare the effectiveness of both emulation approaches upon a multi-wave calibration framework that is becoming popular in the climate modelling community called \history matching". We find that Gaussian processes offer significant benefits to the reduction of parametric uncertainty over regression-only approaches. We find that in a multi-wave experiment, a combination of regression-only emulators initially, followed by Gaussian process emulators for refocussing experiments can be nearly as effective as using Gaussian processes throughout for a fraction of the computational cost. We also discover a number of design and emulator-dependent features of the multi-wave history matching approach that can cause apparent, yet premature, convergence of our estimates of parametric uncertainty. We compare these approaches to calibration in idealised examples and apply it to a well-known geological reservoir mode
The first polluted river? Repeated copper contamination of fluvial sediments associated with Late Neolithic human activity in southern Jordan
Calculation of lifetime lung cancer risks associated with radon exposure, based on various models and exposure scenarios
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Quantitative assessment of sewer overflow performance with climate change in northwest England
Changes in rainfall patterns associated with climate change can affect the operation of a combined sewer system, with the potential increase in rainfall amount. This could lead to excessive spill frequencies and could also introduce hazardous substances into the receiving waters, which, in turn, would have an impact on the quality of shellfish and bathing waters. This paper quantifies the spilling volume, duration and frequency of 19 combined sewer overflows (CSOs) to receiving waters under two climate change scenarios, the high (A1FI), and the low emissions (B1) scenarios, simulated by three global climate models (GCMs), for a study catchment in northwest England. The future rainfall is downscaled, using climatic variables from HadCM3, CSIRO and CGCM2 GCMs, with the use of a hybrid generalized linearâartificial neural network model. The results from the model simulation for the future in 2080 showed an annual increase of 37% in total spill volume, 32% in total spill duration, and 12% in spill frequency for the shellfish water limiting requirements. These results were obtained, under the high emissions scenario, as projected by the HadCM3 as maximum. Nevertheless, the catchment drainage system is projected to cope with the future conditions in 2080 by all three GCMs. The results also indicate that under scenario B1, a significant drop was projected by CSIRO, which in the worst case could reach up to 50% in spill volume, 39% in spill duration and 25% in spill frequency. The results further show that, during the bathing season, a substantial drop is expected in the CSO spill drivers, as predicted by all GCMs under both scenarios
Relationship between erythema effective UV radiant exposure, total ozone, cloud cover and aerosols in southern England, UK
Evidence of an underlying trend in the dependence of erythema effective ultraviolet
(UV) radiant exposure (Her) on changes in the total ozone, cloud cover and
aerosol optical depth (AOD) has been studied using solar ultraviolet
radiation measurements collected over a 25-year period (1991â2015) at Chilton
in the south of England in the UK.
The monthly mean datasets of these measures corrected for underlying
seasonal variation were analysed. When a single linear trend was fitted over
the whole study period between 1991 and 2015, the analyses revealed that the
long-term variability of Her can be best characterised in two
sub-periods (1991â2004 and 2004â2015), where the estimated linear trend was
upward in the first period (1991â2004) but downward in the second period
(2004â2015).
Both cloud cover (CC) and total ozone (TO) were found to have a highly
statistically significant influence on Her, but the influence of the
AOD measure was very small. The radiation amplification factor (RAF) for the
erythema action spectrum due to TO was â1.03 at constant levels of CC over
the whole study period; that is, for a 1.0 % increase in TO, Her
decreases by 1.03 %. Over the first period (1991â2004), the RAF related to
CC was slightly higher at 0.97 compared to that for TO at 0.79. The
proportion of the change in Her explained by the change in CC (47 %)
was much greater than the proportion explained by changes in TO (8 %). For
the second period (2004â2015), the pattern reversed, with the observed RAF
related to TO being â1.25, almost double that of CC (â0.65). Furthermore, in
this period the proportion of variation in Her explained by TO
variation was 33 %, double that of CC at 16 %, while AOD changes had a
negligible effect (1 %).
When the data were examined separately for each season, for the first period
(1991â2004) the greatest effect of TO and CC on Her (i.e. the largest
RAF value) was found during spring. Spring was also the season during which TO and
CC variation explained the greatest proportion of variability in Her
(82 %). In the later period (2004â2015), the RAF and greatest
influence of TO and CC were observed in winter (67 %) and the AOD effect
explained a further 5 % variability in Her.
This study provides evidence that both the increasing trend in Her for
1991â2004 and the decreasing trend in Her for 2004â2015 occur in
response to variation in TO, which exhibits a small increasing tendency over
these periods. CC plays a more important role in the increasing trend in
Her for 1991â2004 than TO, whereas for 2004â2015, the decreasing trend
in Her is less associated with changes in CC and AOD.</p
Teleconnections and local weather orchestrate the reproduction of tit species in the Carpathian Basin
Extent of MGMT promoter methylation correlates with outcome in glioblastomas given temozolomide and radiotherapy
Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia
Background and aims:
Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L.
Methods:
We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g mâ2 yr.â1, 353 ÎŒg lâ1), Whixall Moss (1.37 g mâ2 yr.â1, 1505 ÎŒg lâ1). The total N amount per plant and the contributions of prey/root N to the plantsâ N budget were calculated using a single isotope natural abundance method.
Results:
Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed â Cors Fochno plants captured 62% greater proportions of Diptera.
Conclusions:
Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance
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