Development of a fourfold dielectric-filled reentrant cavity as a beam position monitor (BPM) in a proton therapy facility

At the Paul Scherrer Institute (PSI), the superconducting cyclotron “COMET” delivers a 250 MeV proton beam for radiation therapy in pulses of 1ns at the cyclotron-RF frequency of 72.85 MHz. Accurate measurement of the beam position at proton beam currents of 0.1-10 nA in the beam transport line downstream of the degrader is of crucial importance for the treatment safety and quality, beam alignment and feedback systems. This is essential for efficient operation and beam delivery. These measurements are usually performed with intercepting monitors such as ionization chambers (ICs). In this paper, we present a novel non-intercepting position sensitive cavity resonator. The resonant monitor, tuned to the second harmonic of the cyclotron's RF, is based on the detection of the transverse magnetic dipole mode of the EM field generated by the beam. This mode is only excited for off-center beam positions and is measured with the help of four floating cavities within a common grounded cylinder. This paper discusses the BPM fundamental characteristics, design optimization and the underlying parametric investigations involving the contribution of the different modes and crosstalk. We estimate the expected signals from the prototype BPM for position offsets from simulations and compare them with test-bench measurements and beam measurements with the prototype and the improvised BPM design. We conclude by summarizing the achieved position sensitivity, precision, and measurement bandwidth

Prevalence of SARS-CoV-2 in Household Members and Other Close Contacts of COVID-19 Cases: A Serologic Study in Canton of Vaud, Switzerland.

Research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission within households and other close settings using serological testing is scarce. We invited coronavirus disease 2019 (COVID-19) cases diagnosed between February 27 and April 1, 2020, in Canton of Vaud, Switzerland, to participate, along with household members and other close contacts. Anti-SARS-CoV-2 immunoglobulin G antibodies were measured using a Luminex immunoassay. We estimated factors associated with serological status using generalized estimating equations. Overall, 219 cases, 302 household members, and 69 other close contacts participated between May 4 and June 27, 2020. More than half of household members (57.2%; 95% CI, 49.7%-64.3%) had developed a serologic response to SARS-CoV-2, while 19.0% (95% CI, 10.0%-33.2%) of other close contacts were seropositive. After adjusting for individual and household characteristics, infection risk was higher in household members aged ≥65 years than in younger adults (adjusted odds ratio [aOR], 3.63; 95% CI, 1.05-12.60) and in those not strictly adhering to simple hygiene rules like hand washing (aOR, 1.80; 95% CI, 1.02-3.17). The risk was lower when more than 5 people outside home were met during semiconfinement, compared with none (aOR, 0.35; 95% CI, 0.16-0.74). Individual risk of household members to be seropositive was lower in large households (22% less per each additional person). During semiconfinement, household members of a COVID-19 case were at very high risk of getting infected, 3 times more than close contacts outside home. This highlights the need to provide clear messages on protective measures applicable at home. For elderly couples, who were especially at risk, providing external support for daily basic activities is essential

Pedestrian Road Traffic Injuries in Urban Peruvian Children and Adolescents: Case Control Analyses of Personal and Environmental Risk Factors

BACKGROUND: Child pedestrian road traffic injuries (RTIs) are an important cause of death and disability in poorer nations, however RTI prevention strategies in those countries largely draw upon studies conducted in wealthier countries. This research investigated personal and environmental risk factors for child pedestrian RTIs relevant to an urban, developing world setting. METHODS: This is a case control study of personal and environmental risk factors for child pedestrian RTIs in San Juan de Miraflores, Lima, Perú. The analysis of personal risk factors included 100 cases of serious pedestrian RTIs and 200 age and gender matched controls. Demographic, socioeconomic, and injury data were collected. The environmental risk factor study evaluated vehicle and pedestrian movement and infrastructure at the sites in which 40 of the above case RTIs occurred and 80 control sites. FINDINGS: After adjustment, factors associated with increased risk of child pedestrian RTIs included high vehicle volume (OR 7.88, 95%CI 1.97-31.52), absent lane demarcations (OR 6.59, 95% CI 1.65-26.26), high vehicle speed (OR 5.35, 95%CI 1.55-18.54), high street vendor density (OR 1.25, 95%CI 1.01-1.55), and more children living in the home (OR 1.25, 95%CI 1.00-1.56). Protective factors included more hours/day spent in school (OR 0.52, 95%CI 0.33-0.82) and years of family residence in the same home (OR 0.97, 95%CI 0.95-0.99). CONCLUSION: Reducing traffic volumes and speeds, limiting the number of street vendors on a given stretch of road, and improving lane demarcation should be evaluated as components of child pedestrian RTI interventions in poorer countries

The requirements and challenges in preventing of road traffic injury in Iran. A qualitative study

<p>Abstract</p> <p>Background</p> <p>Road traffic injuries (RTIs) are a major public health problem, especially in low- and middle-income countries. Among middle-income countries, Iran has one of the highest mortality rates from RTIs. Action is critical to combat this major public health problem. Stakeholders involved in RTI control are of key importance and their perceptions of barriers and facilitators are a vital source of knowledge. The aim of this study was to explore barriers to the prevention of RTIs and provide appropriate suggestions for prevention, based on the perceptions of stakeholders, victims and road-users as regards RTIs.</p> <p>Methods</p> <p>Thirty-eight semi-structured interviews were conducted with informants in the field of RTI prevention including: police officers; public health professionals; experts from the road administrators; representatives from the General Governor, the car industry, firefighters; experts from Emergency Medical Service and the Red Crescent; and some motorcyclists and car drivers as well as victims of RTIs. A qualitative approach using grounded theory method was employed to analyze the material gathered.</p> <p>Results</p> <p>The core variable was identified as "The lack of a system approach to road-user safety". The following barriers in relation to RTI prevention were identified as: human factors; transportation system; and organizational coordination. Suggestions for improvement included education (for the general public and targeted group training), more effective legislation, more rigorous law enforcement, improved engineering in road infrastructure, and an integrated organization to supervise and coordinate preventive activities.</p> <p>Conclusion</p> <p>The major barriers identified in this study were human factors and efforts to change human behaviour were suggested by means of public education campaigns and stricter law enforcement. However, the lack of a system approach to RTI prevention was also an important concern. There is an urgent need for both an integrated system to coordinate RTI activities and prevention and a major change in stakeholders' attitudes towards RTI prevention. The focus of all activities should take place on road users' safety.</p

Protecting Vulnerable Road Users from Injury

Aymery Constant and Emmanuel Lagarde discuss policies to protect pedestrians, and pedal and motor cyclists, from injury