Femtosecond laser-induced filamentation typically exhibits pronounced spectral broadening, featuring a bright central white core encircled by concentric colored rings that span from the ultraviolet to the visible range and extend into the infrared. While ionization, self-steepening and self-phase modulation are widely accepted as explanations for the white spot, the underlying physics of colored rings remain inadequately understood by current models, such as Cherenkov radiation and four-wave mixing. In this study, inspired by the observation of similar discrete colored rings produced by cascaded four-wave mixing (CFWM) of intersecting beams, we systematically investigated the relationship between the colored rings in the white-light supercontinuum and CFWM. The CFWM model accurately predicted the correlation between color and divergence angles, thereby enhancing our understanding of spectral broadening in filamentation and providing guidance for optimizing the conversion efficiency and configuration of multi-wavelength ultrashort optical pulses in both spatial and spectral domains.

Modifiable health behaviours, including suboptimal dietary patterns, contribute to the global burden of disease. Messaging to raise awareness about health and nutrition behaviours is an important first step toward behaviour change and promotion of healthy dietary patterns. The aim of this rapid review was to systematically identify best practice recommendations and evidence for the development and characteristics of persuasive health and nutrition messages for awareness raising among adults. Academic reviews and grey literature reports published in English after 2010 that focused on the development or characteristics of general health or nutrition-specific messaging for awareness raising were eligible. MEDLINE Complete, CINHAL, Global Health, Embase and websites of public health organisations were searched between April-July 2024. Data was synthesised narratively. From 12,507 records, 31 were included (27 reviews, 4 reports). There was consistent support for an audience-centred approach to messaging, including audience segmentation, message tailoring and testing with target audiences. It was recommended that messages be disseminated through multiple channels, including mass and social media to facilitate repeat exposure. Message characteristics including use of narratives, simple language, keeping messages short, conveying the general gist rather than detailed information and utilising imagery were considered best practice for persuasive messaging. Nutrition messages that are audience-centred, tailored, thoroughly tested and incorporate elements such as narratives, imagery and simple language are likely to be accepted and persuasive among adults. Findings can be used to inform effective nutrition messaging for awareness raising in research and nutrition promotion settings.