An Electro - Optical Test System for Optimising Operating Conditions of CCD sensors for LSST

We describe the commissioning of a system which has been built to investigate optimal operation of CCDs for the LSST telescope. The test system is designed for low vibration, high stability operation and is capable of illuminating a detector in flat-field, projected spot, projected pattern and Fe-55 configurations. We compare and describe some considerations when choosing a gain calibration method for CCDs which exhibit the brighter-fatter effect. An optimisation study on a prototype device of gain and full well with varying back substrate bias and gate clock levels is presented

Evaluation of an online learning tool to improve medical students' clinical reasoning skills

Background: Evidence suggests that problems in clinical reasoning skills – the thought processes required to make clinical decisions – are the leading cause of diagnostic errors, which can lead to significant patient harm. Theories of learning and clinical reasoning have indicated online patient simulations (OPS) could be a novel approach to improving medical students’ clinical reasoning skills. However, little is known about their impact on clinical reasoning. Methods: I conducted a systematic literature review to explore the effectiveness of OPS. Informed by my review and theory, I co-developed eCREST (electronic Clinical Reasoning Skills Educational Simulation Tool). I assessed the feasibility, acceptability and potential impact of eCREST at three UK medical schools with a feasibility randomised controlled trial (RCT). I explored how students reasoned when using eCREST and what factors influenced reasoning, using a Think Aloud and interview approach with 16 medical students. Results: My systematic review found OPS may be effective at improving medical students’ clinical reasoning skills but the few studies available lacked methodological rigour, so these results should be treated with caution. Uptake and retention in the feasibility trial was acceptable and provided evidence to support a definitive RCT. Impact data suggested eCREST may improve clinical reasoning skills - the intervention group were significantly more likely to gather essential information from the ‘patient’ than controls (OR = 1.4; 95% CI 1.1-1.7, n = 148). Qualitative findings suggested that students use a variety of data gathering strategies and eCREST helped students to structure their data gathering and stay open-minded about diagnosis. Students’ knowledge, confidence and engagement with eCREST also influenced these strategies. Conclusions: Tools like eCREST can improve reasoning skills by helping students to gather essential information and potentially reduce future missed diagnostic opportunities. Evaluations of such tools are now needed within medical curricula, using validated outcome measures to determine effectiveness

Training for design of experiments using a catapult

Design of experiments (DOE) is a powerful approach for discovering a set of process (or design) variables which are most important to the process and then determine at what levels these variables must be kept to optimize the response (or quality characteristic) of interest. This paper presents two catapult experiments which can be easily taught to engineers and managers in organizations to train for design of experiments. The results of this experiment have been taken from a real live catapult experiment performed by a group of engineers in a company during the training program on DOE. The first experiment was conducted to separate out the key factors (or variables) from the trivial and the second experiment was carried out using the key factors to understand the nature of interactions among the key factors. The results of the experiment were analysed using simple but powerful graphical tools for rapid and easier understanding of the results to engineers with limited statistical competency

Rice bundle sheath cell shape is regulated by the timing of light exposure during leaf development

Plant leaves contain multiple cell types which achieve distinct characteristics whilst still coordinating development within the leaf. The bundle sheath possesses larger individual cells and lower chloroplast content than the adjacent mesophyll, but how this morphology is achieved remains unknown. To identify regulatory mechanisms determining bundle sheath cell morphology we tested the effects of perturbing environmental (light) and endogenous signals (hormones) during leaf development of Oryza sativa (rice). Total chloroplast area in bundle sheath cells was found to increase with cell size as in the mesophyll but did not maintain a ‘set‐point’ relationship, with the longest bundle sheath cells demonstrating the lowest chloroplast content. Application of exogenous cytokinin and gibberellin significantly altered the relationship between cell size and chloroplast biosynthesis in the bundle sheath, increasing chloroplast content of the longest cells. Delayed exposure to light reduced the mean length of bundle sheath cells but increased corresponding leaf length, whereas premature light reduced final leaf length but did not affect bundle sheath cells. This suggests that the plant hormones cytokinin and gibberellin are regulators of the bundle sheath cell‐chloroplast relationship and that final bundle sheath length may potentially be affected by light‐mediated control of exit from the cell cycle

The Longitudinal Impact of Social Media Use on UK Adolescents' Mental Health: Longitudinal Observational Study

BACKGROUND: Cross-sectional studies have found a relationship between social media use and depression and anxiety in young people. However, few longitudinal studies using representative data and mediation analysis have been conducted to understand the causal pathways of this relationship. OBJECTIVE: This study aims to examine the longitudinal relationship between social media use and young people's mental health and the role of self-esteem and social connectedness as potential mediators. METHODS: The sample included 3228 participants who were 10- to 15-year-olds from Understanding Society (2009-2019), a UK longitudinal household survey. The number of hours spent on social media was measured on a 5-point scale from "none" to "7 or more hours" at the ages of 12-13 years. Self-esteem and social connectedness (number of friends and happiness with friendships) were measured at the ages of 13-14 years. Mental health problems measured by the Strengths and Difficulties Questionnaire were assessed at the ages of 14-15 years. Covariates included demographic and household variables. Unadjusted and adjusted multilevel linear regression models were used to estimate the association between social media use and mental health. We used path analysis with structural equation modeling to investigate the mediation pathways. RESULTS: In adjusted analysis, there was a nonsignificant linear trend showing that more time spent on social media was related to poorer mental health 2 years later (n=2603, β=.21, 95% CI 0.43 to 0.84; P=.52). In an unadjusted path analysis, 68% of the effect of social media use on mental health was mediated by self-esteem (indirect effect, n=2569, β=.70, 95% CI 0.15-1.30; P=.02). This effect was attenuated in the adjusted analysis, and it was found that self-esteem was no longer a significant mediator (indirect effect, n=2316, β=.24, 95% CI 0.12 to 0.66; P=.22). We did not find evidence that the association between social media and mental health was mediated by social connectedness. Similar results were found in imputed data. CONCLUSIONS: There was little evidence to suggest that more time spent on social media was associated with later mental health problems in UK adolescents. This study shows the importance of longitudinal studies to examine this relationship and suggests that prevention strategies and interventions to improve mental health associated with social media use could consider the role of factors like self-esteem

The Impact of Social Media Use Interventions on Mental Well-Being: Systematic Review

BACKGROUND: There is some evidence that more social media use is related to poorer mental well-being and that social media use can become problematic when it starts to interfere with a person's daily life and mental well-being. To address this issue and improve users' mental well-being, social media use interventions (eg, abstinence from social media) have been developed and evaluated. However, there is limited understanding of the effectiveness of these interventions in improving mental well-being. OBJECTIVE: This systematic review aimed to synthesize the literature on the effectiveness of social media use interventions in improving mental well-being in adults. METHODS: A systematic search (January 1, 2004, to July 31, 2022) was completed across 3 databases in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Experimental studies evaluating the impact of social media use interventions on mental well-being in adults were included. Outcomes related to mental well-being, such as depression, anxiety, stress, and loneliness, were included. A narrative synthesis without meta-analysis was completed to summarize the study characteristics and effectiveness by outcome and intervention type. The Effective Public Health Practice Project Quality Assessment Tool was used to measure the quality of the studies. RESULTS: Of the 2785 studies identified through the systematic search, 23 (0.83%) were included in the analysis. Many of the included studies (9/23, 39%) found improvements in mental well-being, some (7/23, 30%) found mixed effects, and others (7/23, 30%) found no effect on mental well-being. Therapy-based interventions that used techniques such as cognitive behavioral therapy were more effective than limiting use of social media or full abstinence from social media, with 83% (5/6) of these studies showing improvements in mental well-being compared with 20% (1/5) and 25% (3/12), respectively. Depression was the most frequently investigated and improved outcome with 70% (7/10) of the studies showing a significant improvement in depression after the intervention, whereas other outcomes showed more varied results. Quality was poor, with 96% (22/23) of the studies receiving a weak global score, mostly for issues related to selection bias because most of the studies (16/23, 70%) used a convenience sampling of university students. CONCLUSIONS: This review provides some evidence that social media use interventions are effective in improving mental well-being, especially for depression and when using therapy-based interventions. Further experimental and longitudinal research is needed with representative samples to investigate who may benefit most from social media use interventions. This will help to develop guidance and recommendations for policy makers and clinicians on how best to manage problematic social media use

The longitudinal effect of social media use on adolescent mental health in the UK: findings from the UK Longitudinal Household Study

BACKGROUND: Cross-sectional studies have suggested an association between the use of social media and depression and anxiety in young people. We examined the longitudinal relationship between social media use and young people's mental health, and the role of self-esteem and social connectedness as potential mediators. METHODS: Adolescents (aged 10-15 years) from the UK Longitudinal Household Study (2009-19) were included. Mental health was measured by the Strengths and Difficulties Questionnaire Total Difficulties score. The number of hours spent on social media was measured on a 5-point scale, from zero to ≥7 h. Self-esteem and social connectedness were measured at ages 13-14 years. Covariates included demographic and household variables. Unadjusted and adjusted multilevel linear regression models explored whether social media use at ages 12-13 years predicted mental health at ages 14-15 years (expressed as beta values and 95% CIs). Path analysis with structural equation modelling was used to investigate the mediation pathways. FINDINGS: We included 3228 adolescents (1659 [51·4%] girls and 1569 [48·6%] boys) for whom social media and mental health data at ages 12-13 years and 14-15 years were available. In adjusted analysis, no association between time spent on social media and poorer mental health was identified (n=2603; b=0·21 [95% CI -0·43 to 0·84]; p=0·52). In adjusted path analysis, there was no mediation of self-esteem (indirect effect; n=2316; b=0·24 [95% CI -0·12 to 0·66]; p=0·22) or social connectedness (indirect effect; -0·03 [-0·20 to 0·12]; p=0·74), but in unadjusted analysis, 68% of the effect of social media use on mental health was mediated by self-esteem (indirect effect; n=2569; 0·70 [0·15 to 1·30]; p=0.016) but not by social connectedness. Similar results were found when the analysis was re-run on a multiply imputed dataset that filled in missing values using multiple imputation. INTERPRETATION: Our data show the importance of longitudinal evidence. We found there was little evidence to suggest a causal relationship between the use of social media and mental health issues 2 years later. Interventions that address social media use alone might not improve young people's mental health, and considering factors such as self-esteem might be more effective. FUNDING: UK National Institute for Health Research School for Public Health Research (grant reference PD-SPH-2015). The views expressed are those of the authors and not necessarily those of the National Institute for Health Research or the UK Department of Health and Social Care