Waves propagating in a medium with highly variable refractive index tend to focus forming caustics. The energy content of the waveeeld in the vicinity of a caustic is higher than that of the ambient eld away from the caustic. Consequently, waves scattering from heterogeneities located near caustics have more energy than a eld scattering a little further away from the caustic. For a suitable cho...

True amplitude one-way wave equations provide full waveform solutions that agree with leading order WKBJ solutions of the full, two-way wave equation away from caustics and other anomalies of the ray field. Both a proof of this fact and numerical examples are available in the literature. Near smooth caustics, ray-theoretic solutions fail for both the one-way and two-way wave equations; the WKBJ...

OBJECTIVES To determine circumstances surrounding the ingestion of caustic substances, the incidence of respiratory and gastrointestinal symptoms at presentation, and the degree of investigation and active treatment during hospitalisation. Long term respiratory and gastrointestinal sequelae were also studied. DESIGN Retrospective case note study covering a 10 year period. SETTING Tertiary c...

We numerically investigate the long–time evolution of density perturbations after the first appearance of caustics in an expanding cosmological model with one–dimensional ‘single–wave’ initial conditions. Focussing on the time–intervals of caustic appearances and the spatial distribution of caustics at subsequent times, we find that the time–intervals of caustic appearances approach a constant,...

BACKGROUND Although the outcomes of caustic ingestion differ between children and adults, it is unclear whether such outcomes differ among adults as a function of their age. This retrospective study was performed to ascertain whether the clinical outcomes of caustic ingestion differ significantly between elderly and non-elderly adults. METHODS Medical records of patients hospitalized for caus...

Corrosive ingestion is a rare but potentially devastating event and, despite the availability of effective preventive public health strategies, injuries continue to occur. Most clinicians have limited personal experience and rely on guidelines; however, uncertainty persists about best clinical practice. Ingestions range from mild cases with no injury to severe cases with full thickness necrosis...

DESCRIPTION A 75-year-old, previously healthy, woman presented to the emergency room with bilateral hand wounds. Her medical history revealed the use of a sodium hydroxide (NaOH)—impregnated swab without gloves for approximately 2–3 h. Within several hours she felt a burning sensation and noticed significant hyperaemia and blisters over her left interdigitals and her right tenar eminence and fi...