No abstract

Koi carps frequently swim in burst-and-coast style, which consists of a burst phase and a coast phase. We quantify the swimming kinematics and the flow patterns generated by the carps in burst-and-coast swimming. In the burst phase, the carps burst in two modes: in the first, the tail beats for at least one cycle (multiple tail-beat mode); in the second, the tail beats for only a half-cycle (half tail-beat mode). The carp generates a vortex ring in each half-cycle beat. The vortex rings generated during bursting in multiple tail-beat mode form a linked chain, but only one vortex ring is generated in half tail-beat mode. The wake morphologies, such as momentum angle and jet angle, also show much difference between the two modes. In the burst phase, the kinematic data and the impulse obtained from the wake are linked to obtain the drag coefficient (C d,burst Ϸ0.242). In the coast phase, drag coefficient (C d,coast Ϸ0.060) is estimated from swimming speed deceleration. Our estimation suggests that nearly 45% of energy is saved when burst-and-coast swimming is used by the koi carps compared with steady swimming at the same mean speed.

IMPORTANCE Previous studies have suggested that patients with cancer may be at an increased risk of death from unintentional injury, but to our knowledge, no large studies have examined the rates of death from unintentional injury among patients with cancer. OBJECTIVE To characterize the incidence of death from unintentional injury among patients with cancer in the United States. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort study included patients diagnosed with a first primary cancer between January 1, 1973, and December 31, 2015, identified from the Surveillance, Epidemiology, and End Results (SEER) program data. Comparisons with the general US population were based on mortality data collected by the National Center for Health Statistics. Analyses were performed from February 1, 2019, to August 15, 2019. MAIN OUTCOMES AND MEASURES Rates and standardized mortality ratios (SMRs) of death from unintentional injury among patients with cancer. RESULTS A total of 8 271 020 patients with cancer were included in this study (50.2% female; mean [SD] age, 63.0 [15.7] years). Among them, 40 599 deaths from unintentional injury were identified. The rates of death from unintentional injury were 81.90 per 100 000 person-years among patients with cancer and 51.21 per 100 000 person-years in the corresponding US general population. The