Extremely Dense Gamma-Ray Pulses in Electron Beam-Multifoil Collisions.

Sources of high-energy photons have important applications in almost all areas of research. However, the photon flux and intensity of existing sources is strongly limited for photon energies above a few hundred keV. Here we show that a high-current ultrarelativistic electron beam interacting with multiple submicrometer-thick conducting foils can undergo strong self-focusing accompanied by efficient emission of gamma-ray synchrotron photons. Physically, self-focusing and high-energy photon emission originate from the beam interaction with the near-field transition radiation accompanying the beam-foil collision. This near field radiation is of amplitude comparable with the beam self-field, and can be strong enough that a single emitted photon can carry away a significant fraction of the emitting electron energy. After beam collision with multiple foils, femtosecond collimated electron and photon beams with number density exceeding that of a solid are obtained. The relative simplicity, unique properties, and high efficiency of this gamma-ray source open up new opportunities for both applied and fundamental research including laserless investigations of strong-field QED processes with a single electron beam.

An intervention for enhancing public health crisis response willingness among local health department workers: a qualitative programmatic analysis.

OBJECTIVES: This study evaluated the impact of a novel multimethod curricular intervention using a train-the-trainer model: the Public Health Infrastructure Training (PHIT). PHIT was designed to 1) modify perceptions of self-efficacy, response efficacy, and threat related to specific hazards and 2) improve the willingness of local health department (LHD) workers to report to duty when called upon. METHODS: Between June 2009 and October 2010, eight clusters of US LHDs (n = 49) received PHIT. Two rounds of focus groups at each intervention site were used to evaluate PHIT. The first round of focus groups included separate sessions for trainers and trainees, 3 weeks after PHIT. The second round of focus groups combined trainers and trainees in a single group at each site 6 months following PHIT. During the second focus group round, participants were asked to self-assess their preparedness before and after PHIT implementation. SETTING: Focus groups were conducted at eight geographically representative clusters of LHDs. PARTICIPANTS: Focus group participants included PHIT trainers and PHIT trainees within each LHD cluster. MAIN OUTCOME MEASURE(S): Focus groups were used to assess attitudes toward the curricular intervention and modifications of willingness to respond (WTR) to an emergency; self-efficacy; and response efficacy. RESULTS: Participants reported that despite challenges in administering the training, PHIT was well designed and appropriate for multiple management levels and disciplines. Positive mean changes were observed for all nine self-rated preparedness factors (p < 0.001). The findings show PHIT's benefit in improving self-efficacy and WTR among participants. CONCLUSIONS: The PHIT has the potential to enhance emergency response willingness and related self-efficacy among LHD workers.

Narrative communication in cancer prevention and control: a framework to guide research and application.

Narrative forms of communication-including entertainment education, journalism, literature, testimonials, and storytelling-are emerging as important tools for cancer prevention and control. To stimulate critical thinking about the role of narrative in cancer communication and promote a more focused and systematic program of research to understand its effects, we propose a typology of narrative application in cancer control. We assert that narrative has four distinctive capabilities: overcoming resistance, facilitating information processing, providing surrogate social connections, and addressing emotional and existential issues. We further assert that different capabilities are applicable to different outcomes across the cancer control continuum (e.g., prevention, detection, diagnosis, treatment, survivorship). This article describes the empirical evidence and theoretical rationale supporting propositions in the typology, identifies variables likely to moderate narrative effects, raises ethical issues to be addressed when using narrative communication in cancer prevention and control efforts, and discusses potential limitations of using narrative in this way. Future research needs based on these propositions are outlined and encouraged.