Design of the first fusion experiment to achieve target energy gain G>1.

In this work we present the design of the first controlled fusion laboratory experiment to reach target gain G>1 N221204 (5 December 2022) [Phys. Rev. Lett. 132, 065102 (2024)10.1103/PhysRevLett.132.065102], performed at the National Ignition Facility, where the fusion energy produced (3.15 MJ) exceeded the amount of laser energy required to drive the target (2.05 MJ). Following the demonstration of ignition according to the Lawson criterion N210808, experiments were impacted by nonideal experimental fielding conditions, such as increased (known) target defects that seeded hydrodynamic instabilities or unintentional low-mode asymmetries from nonuniformities in the target or laser delivery, which led to reduced fusion yields less than 1 MJ. This Letter details design changes, including using an extended higher-energy laser pulse to drive a thicker high-density carbon (also known as diamond) capsule, that led to increased fusion energy output compared to N210808 as well as improved robustness for achieving high fusion energies (greater than 1 MJ) in the presence of significant low-mode asymmetries. For this design, the burnup fraction of the deuterium and tritium (DT) fuel was increased (approximately 4% fuel burnup and a target gain of approximately 1.5 compared to approximately 2% fuel burnup and target gain approximately 0.7 for N210808) as a result of increased total (DT plus capsule) areal density at maximum compression compared to N210808. Radiation-hydrodynamic simulations of this design predicted achieving target gain greater than 1 and also the magnitude of increase in fusion energy produced compared to N210808. The plasma conditions and hotspot power balance (fusion power produced vs input power and power losses) using these simulations are presented. Since the drafting of this manuscript, the results of this paper have been replicated and exceeded (N230729) in this design, together with a higher-quality diamond capsule, setting a new record of approximately 3.88MJ of fusion energy and fusion energy target gain of approximately 1.9.

Interpretive analysis of 85 systematic reviews suggests that narrative syntheses and meta-analyses are incommensurate in argumentation.

Using Toulmin's argumentation theory, we analysed the texts of systematic reviews in the area of workplace health promotion to explore differences in the modes of reasoning embedded in reports of narrative synthesis as compared with reports of meta-analysis. We used framework synthesis, grounded theory and cross-case analysis methods to analyse 85 systematic reviews addressing intervention effectiveness in workplace health promotion. Two core categories, or 'modes of reasoning', emerged to frame the contrast between narrative synthesis and meta-analysis: practical-configurational reasoning in narrative synthesis ('what is going on here? What picture emerges?') and inferential-predictive reasoning in meta-analysis ('does it work, and how well? Will it work again?'). Modes of reasoning examined quality and consistency of the included evidence differently. Meta-analyses clearly distinguished between warrant and claim, whereas narrative syntheses often presented joint warrant-claims. Narrative syntheses and meta-analyses represent different modes of reasoning. Systematic reviewers are likely to be addressing research questions in different ways with each method. It is important to consider narrative synthesis in its own right as a method and to develop specific quality criteria and understandings of how it is carried out, not merely as a complement to, or second-best option for, meta-analysis. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd.

Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums.

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 µm diameter hot core.

Attitudes to walking and cycling among children, young people and parents: a systematic review.

BACKGROUND: Promoting walking and cycling as a part of everyday activity is seen as a strategy for tackling obesity and chronic disease. Policy needs to be based on evidence about people's views of walking and cycling as well as effects of interventions. METHODS: Studies of the views of children, young people and parents about walking and cycling were searched for systematically, and a framework analysis applied. The findings were synthesised and compared with the findings of an effectiveness review of interventions for encouraging walking and cycling as an alternative to motorised transport. RESULTS: The synthesis of views described a culture of car use, fed by a fear and dislike of local environments and parental responses that emphasised children's safety at the expense of developing their independence, despite children expressing responsible attitudes towards transport choices. Comparison with effectiveness literature found that most evaluated interventions targeted only the public's fear and dislike of local environments. CONCLUSION: Interventions need to address pedestrian and cyclist safety, perceptions of risk, and parental norms regarding children's independence.

Young people and mental health: novel methods for systematic review of research on barriers and facilitators.

This paper describes how barriers to, and facilitators of, good mental health amongst young people (11-21 years) were elucidated from a systematic review of studies of young people's views and how these barriers and facilitators were compared with effectiveness studies to identify effective and appropriate interventions, promising interventions needing further evaluation and the need for further intervention. All studies were published before 2000. No clear pattern for effectiveness emerged in terms of mental health promotion focus, the type of intervention, intervention provider or young people. Well-evaluated interventions neither always target what we know young people themselves see as important barriers to their mental health (for instance, loss of friends and family, violence and bullying) nor always build on what they see as key facilitators, particularly their preferred coping strategies. In particular, while young people see material and physical resources as major influences on their mental health, few evaluated interventions targeted these. Rigorously evaluated interventions more often addressed priorities not raised by young people themselves and populations at low risk for mental health problems. These innovative review methods can inform intervention development and evaluation in a new way based on the strengths and needs identified by the target population.

Young people and physical activity: a systematic review matching their views to effective interventions.

A systematic review was conducted to examine the barriers to, and facilitators of, physical activity among young people (11-16 years). The review focused on the wider determinants of health, examining community- and society-level interventions. Four trials and 16 studies of young people's views were included. Evidence for the effectiveness of the interventions was limited, with some suggestions of improvements in knowledge and possible differences according to gender. Young women in particular identified barriers to physical activity associated with certain ways of providing physical education in schools. Young people in general identified a need for increased choice and facilities within the community and emphasized physical activity's social side. Some of the barriers and facilitators identified by young people had been addressed by 'soundly evaluated' effective interventions but significant gaps were identified where no evaluated interventions appear to have been published (e.g. initiatives explicitly addressing gender issues or the combination of sport and other leisure activities), or where there were no soundly evaluated interventions. Rigorous evaluation is required particularly to assess initiatives that address the limited practical and material resources that young people identify as barriers to physical activity.

Young people and healthy eating: a systematic review of research on barriers and facilitators.

A systematic review was conducted to examine the barriers to, and facilitators of, healthy eating among young people (11-16 years). The review focused on the wider determinants of health, examining community- and society-level interventions. Seven outcome evaluations and eight studies of young people's views were included. The effectiveness of the interventions was mixed, with improvements in knowledge and increases in healthy eating but differences according to gender. Barriers to healthy eating included poor school meal provision and ease of access to, relative cheapness of and personal taste preferences for fast food. Facilitators included support from family, wider availability of healthy foods, desire to look after one's appearance and will-power. Friends and teachers were generally not a common source of information. Some of the barriers and facilitators identified by young people had been addressed by soundly evaluated effective interventions, but significant gaps were identified where no evaluated interventions appear to have been published (e.g. better labelling of food products), or where there were no methodologically sound evaluations. Rigorous evaluation is required particularly to assess the effectiveness of increasing the availability of affordable healthy food in the public and private spaces occupied by young people.

Short-term adverse health effects in a community exposed to a large polyvinylchloride plastics fire.

The purpose of this study was the documentation of the short-term morbidity and mortality experiences of an urban community exposed to the airborne byproducts of a large polyvinylchloride plastics fire. The authors administered a survey to representatives of each household who had lived in an area evacuated during the fire. A time-series analysis was performed on emergency room visits and admissions for all hospitals in the city. Chloracne surveillance was instituted. Sixty-two percent of the individuals surveyed from the evacuation area reported no health concerns or symptoms related to the fire. Thirty-eight percent of the residents reported symptoms, and less than 2% of those surveyed reported that they sought medical attention for their health concerns. There was no evidence of increased hospital admissions or emergency room use during and immediately following the fire. No cases of chloracne were reported, and no deaths or serious injuries occurred during the fire. Polyvinylchloride plastics recycling plants pose potential health hazards to civilian populations. Public health authorities should be prepared to assess population health status rapidly and to disseminate relevant health information in a timely way during a crisis.

Transferring public-health nursing research to health-system planning: assessing the relevance and accessibility of systematic reviews.

A descriptive study was designed to gain an understanding of the research needs, perceptions of barriers to research utilization, and attitudes towards systematic reviews of decision-makers in public health at the level of systems planning. Public-health consultants and managers in Ontario were surveyed about barriers to research utilization and awareness of and attitudes towards systematic reviews as a method of/vehicle for research transfer. Access to 5 completed reviews was provided in summary, abstract, and full form, and on diskette, hard copy, and Internet. A follow-up survey at 3 months assessed use, relevance, application, and further dissemination of the reviews. A total of 242 people in positions of public-health policy and decision-making participated. Respondents reported a great, largely unmet, need for research evidence. They viewed systematic reviews as likely to overcome the barriers to research use related to critical appraisal, time, timeliness, availability, cost and credibility, but not the barriers related to policy climate, authority, or implementation resources. Three months after requesting a review, 93% said they would follow it up; 91% remembered receiving it, and 71% of these had read it while 23% stated it played a part in program planning or decision-making.

Relation of growth delay to cure for experimental tumour systems conforming to Poisson cure statistics.

In tumour regrowth-delay experiments, the analysis of results in the higher dose ranges may be complicated by a dose-dependent proportion of non-recurrent (cured) tumours, whose inclusion in the analysis is not straightforward. A study of the relation of growth delay to cure has been carried out using a model of tumour response which assumes Poisson (single-cell) cure statistics and exponential regrowth kinetics of recurrent tumours, and which makes use of Monte Carlo simulation techniques to represent the effects of inter-tumour heterogeneity. This approach yields correction factors compensating for tumour cures in growth-delay experiments. For homogeneous tumour systems (all tumours and treatments identical) these corrections are small and not significantly different from corrections obtained using the "long delay" procedure suggested previously (Denekamp, 1980; Fowler et al., 1980). For heterogeneous systems, however, correction factors increase with the heterogeneity of the system, and may become quite large. It is concluded that the quantitative assessment of heterogeneity is required, and a possible approach to this is suggested. Should evaluation of heterogeneity prove feasible, it will allow more efficient use of tumour-response data, and may permit realistic estimates of clonogenic cell survival in situ.

Characteristic species dependent growth patterns of mammalian neoplasms.

Evidence is presented, arising from an analysis of published data on tumour growth in three species of laboratory animals and in human multiple myeloma supporting a species specific relation between two supposedly independent parameters in the Gompertz equations frequently used to quantify tumour growth curves. This evidence supports the conjecture of Norton et al. (1976), based on their observations of the growth kinetics of a murine melanoma and a rat mammary carcinoma, that such a relation may be a general feature of tumour growth. Published data on the growth of xenografts of human colorectal tumours in immune-deprived mice suggests that the observed growth relation reflects the ability of a particular species to support a tumour of a certain maximum size. The existence of this relation greatly simplifies the task of predicting complete patterns of undisturbed neoplastic growth in these species.

Prediction of the complete growth pattern of human multiple myeloma from restricted initial measurements.

A method is presented for predicting the complete growth pattern of human IgG multiple myeloma from a few initial measurements of tumour cell number. This permits identification of patterns of undisturbed neoplastic growth in individual patients whose therapy cannot ethically be withheld for long periods. Since the unperturbed growth pattern is a necessary part of the information required for the prediction of individual patient response to alternative treatment schedules, the prospects for improved treatment of human multiple myeloma by optimal scheduling of drug administration are greatly increased.