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High-energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. To increase the energy of the particles or to reduce the size of the accelerator, new acceleration schemes need to be developed. Plasma wakefield acceleration 1 – 5 , in which the electrons in a plasma are excited, leading to strong electric fields (so called ‘wakefields’), is one such promising acceleration technique. Experiments have shown that an intense laser pulse 6 – 9 or electron bunch 10 , 11 traversing a plasma can drive electric fields of tens of gigavolts per metre and above—well beyond those achieved in conventional radio-frequency accelerators (about 0.1 gigavolt per metre). However, the low stored energy of laser pulses and electron bunches means that multiple acceleration stages are needed to reach very high particle energies 5 , 12 . The use of proton bunches is compelling because they have the potential to drive wakefields and to accelerate electrons to high energy in a single acceleration stage 13 . Long, thin proton bunches can be used because they undergo a process called self-modulation 14 – 16 , a particle–plasma interaction that splits the bunch longitudinally into a series of high-density microbunches, which then act resonantly to create large wakefields. The Advanced Wakefield (AWAKE) experiment at CERN 17 – 19 uses high-intensity proton bunches—in which each proton has an energy of 400 gigaelectronvolts, resulting in a total bunch energy of 19 kilojoules—to drive a wakefield in a ten-metre-long plasma. Electron bunches are then injected into this wakefield. Here we present measurements of electrons accelerated up to two gigaelectronvolts at the AWAKE experiment, in a demonstration of proton-driven plasma wakefield acceleration. Measurements were conducted under various plasma conditions and the acceleration was found to be consistent and reliable. The potential for this scheme to produce very high-energy electron bunches in a single accelerating stage 20 means that our results are an important step towards the development of future high-energy particle accelerators 21 , 22 . Electron acceleration to very high energies is achieved in a single step by injecting electrons into a ‘wake’ of charge created in a 10-metre-long plasma by speeding long proton bunches.

Sea urchin grazing can result in regime shift from productive kelp beds to sea urchin barren grounds that represent an alternative and stable reef state. Here we examine the stability of urchin barrens by defining the demographics of the Australian urchin Heliocidaris erythrogramma during regime shift to, and maintenance of, barrens. Inverse-logistic modeling of calibrated in situ annual growth increments for five urchin populations, two from kelp beds and three from barrens, demonstrate slowing of urchin growth as availability and consumption of standing and/or drift kelp declines. Population age structures were predicted from observed sizes over four years (2012–2015, n = 5,864 individuals), which indicated stable age distributions for populations both maintaining barrens and actively grazing among kelp beds. Younger age distributions occurred on barrens whereas more mature populations existed within kelp beds, indicating that high recruitment facilitates maintenance of barrens while overgrazing appeared more reliant on adult urchins grazing from the edges of kelp beds, as opposed to juvenile recruitment among kelp. Leslie-matrix projections indicated potential for unchecked population growth for all study populations, but which varied depending on whether local or regional recruitment rates were modeled. Ultimately, strong density dependence was observed to check population growth; with high-recruitment/high-density populations offset by reduced growth rates and decreased longevity. Increasing disease rates among older urchins in high-density populations were consistent with observed density-dependent mortality, while tethering of healthy urchins revealed highest predation on small urchins within kelp beds, suggesting some remnant resilience of declining kelp habitat. Results demonstrate that the greatest opportunity for urchin population control is when reefs exist in the kelp bed state, at which point urchin populations are prone to negative feedback. Conversely, control of urchins on barrens is demonstrably difficult given positive density-dependent feedbacks that act to stabilize population size and which evidently underpin the hysteresis effect governing the persistence of this alternative stable state.

Objective. To incorporate the My Life, My Story program into pharmacy learners’ training and assess its impact on the learners’ self-reported patient-centered care competencies. Methods. Fourth professional year (P4) pharmacy students and first and second year (PGY-1 and PGY-2) pharmacy residents at a veterans health care facility were instructed to identify a patient to interview during their rotation. Following a guide provided to them, the learners conducted an interview and wrote their patient’s story. Learners also completed anonymous, voluntary, pre- and post-activity surveys online intended to assess their patient-centered care competencies and report the impact of and overall perceptions about the experience. The total number of learners and stories were tracked by reviewing patients’ medical records. Results. Between July 2016 and February 2019, 34 pharmacy learners completed 40 veterans’ life stories. The participants included 28 P4 pharmacy students and four PGY-1 and two PGY-2 pharmacy residents. Of the 34 learners, 9 (26%) completed the optional, anonymous pre-activity survey and 16 (47%) completed the post-activity survey. On a Likert scale (1=poor to 5=excellent), learners reported a significant improvement in their ability to let the patient tell their story, view the patient as a whole person, and show care and compassion. Overall, participants reported that the learning experience was a good use of their time to a great (56%) or large (28%) extent and helped them to foster a positive relationship with their patients. Conclusion. Integrating the My Life, My Story program into pharmacy learning experiences may assist in developing patient-centered care skills in the clinical setting.

A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self -modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.

The heavy-ion physics programme at CERN relies on lead ion beams. In recent years, interest in conducting experiments with nuclei lighter than lead has grown significantly. Before new ion species can be considered operational for experiments, their feasibility for production and acceleration throughout the accelerator complex must be assessed. Several ion species have been tested in the past: argon and xenon were delivered for NA61/SHINE physics in 2015 and 2017, with xenon also reaching the LHC in 2017. More recent tests in the CERN accelerator complex include oxygen in 2023, in preparation for an LHC oxygen run in 2025; krypton, as a candidate for HL-LHC in Run 5 (2036-2041); and magnesium in 2024, requested by NA61/SHINE, an SPS North Area fixed target experiment. A boron test for the NA61/SHINE is planned during Long Shutdown 3 (2026-2029). This contribution reviews the performance of the ion complex with recent oxygen and magnesium beam tests and future plans for developing new ion species.

Background: Cognitive models propose that faulty appraisal of anomalous experiences is critical in developing psychosis, particularly delusions. A data gathering bias may be fundamental to abnormal appraisal. Aims: To examine whether there is a data gathering bias in people at high risk of developing psychosis. Method: Individuals with an at-risk mental state (n=35) were compared with a matched group of healthy volunteers (n=23). Participants were tested using a modified version of the 'beads' reasoning task with different levels of task difficulty. Results: When task demands were high, the at-risk group made judgements on the basis of less information than the control group (P <0.05). Within both groups, jumping to conclusions was directly correlated with the severity of abnormal beliefs and intolerance of uncertainty (P <0.05). In the at-risk group it was also associated with impaired working memory (P <0.05), whereas in the control group poor working memory was associated with a more conservative response style (P <0.05). Conclusions: People with an at-risk mental state display a jumping to conclusions reasoning style, associated with impaired working memory and intolerance of uncertainty. This may underlie a tendency to develop abnormal beliefs and a vulnerability to psychosis. Declaration of interest: None. Funding detailed in Acknowledgements. Adapted from the source document.

People with prodromal symptoms have a very high risk of developing psychosis. To use functional magnetic resonance imaging to examine the neurocognitive basis of this vulnerability. Cross-sectional comparison of regional activation in individuals with an'at-risk mental state' (at-risk group: n=17), patients with first-episode schizophreniform psychosis (psychosis group: n=10) and healthy volunteers (controls: n=15) during an overt verbal fluency task and an N-back working memory task. A similar pattern of between-group differences in activation was evident across both tasks. Activation in the at-risk group was intermediate relative to that in controls and the psychosis group in the inferior frontal and anterior cingulate cortex during the verbal fluency task and in the inferior frontal, dorsolateral prefrontal and parietal cortex during the N-back task. The at-risk mental state is associated with abnormalities of regional brain function that are qualitatively similar to, but less severe than, those in patients who have recently presented with psychosis.

Despite the increasing development of early intervention services for psychosis, little is known about their cost-effectiveness. We assessed the cost-effectiveness of Outreach and Support in South London (OASIS), a service for people with an at-risk mental state (ARMS) for psychosis. The costs of OASIS compared to care as usual (CAU) were entered in a decision model and examined for 12- and 24-month periods, using the duration of untreated psychosis (DUP) and rate of transition to psychosis as key parameters. The costs were calculated on the basis of services used following referral and the impact on employment. Sensitivity analysis was used to test the robustness of all the assumptions made in the model. Over the initial 12 months from presentation, the costs of the OASIS intervention were pound1872 higher than CAU. However, after 24 months they were pound961 less than CAU. This model suggests that services that permit early detection of people at high risk of psychosis may be cost saving.

Parasitic wasps are among the most species‐rich groups on Earth. A major cause of this diversity may be local adaptation to host species. However, little is known about variation in host specificity among populations within parasitoid species. Not only is such knowledge important for understanding host‐driven speciation, but because parasitoids often control pest insects and narrow host ranges are critical for the safety of biological control introductions, understanding variation in specificity and how it arises are crucial applications in evolutionary biology. Here, we report experiments on variation in host specificity among 16 populations of an aphid parasitoid, Aphelinus certus. We addressed several questions about local adaptation: Do parasitoid populations differ in host ranges or in levels of parasitism of aphid species within their host range? Are differences in parasitism among parasitoid populations related to geographical distance, suggesting clinal variation in abundances of aphid species? Or do nearby parasitoid populations differ in host use, as would be expected if differences in aphid abundances, and thus selection, were mosaic? Are differences in parasitism among parasitoid populations related to genetic distances among them? To answer these questions, we measured parasitism of a taxonomically diverse group of aphid species in laboratory experiments. Host range was the same for all the parasitoid populations, but levels of parasitism varied among aphid species, suggesting adaptation to locally abundant aphids. Differences in host specificity did not correlate with geographical distances among parasitoid populations, suggesting that local adaption is mosaic rather than clinal, with a spatial scale of less than 50 kilometers. We sequenced and assembled the genome of A. certus, made reduced‐representation libraries for each population, analyzed for single nucleotide polymorphisms, and used these polymorphisms to estimate genetic differentiation among populations. Differences in host specificity correlated with genetic distances among the parasitoid populations.

In this article, we briefly summarize the experiments performed during the first run of the Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research). The final goal of AWAKE Run 1 (2013–2018) was to demonstrate that 10–20 MeV electrons can be accelerated to GeV energies in a plasma wakefield driven by a highly relativistic self-modulated proton bunch. We describe the experiment, outline the measurement concept and present first results. Last, we outline our plans for the future. This article is part of the Theo Murphy meeting issue ‘Directions in particle beam-driven plasma wakefield acceleration’.