Railways guide vehicles along tracks and connect places through a coordinated system of routes, structures, equipment, and operation. The rails themselves are the most visible continuous feature, but they are only part of the whole arrangement. Stations, junctions, bridges, power systems, and maintenance facilities all contribute to how a railway works. Its usefulness depends on …

Continue reading “Railways as connected systems”

Coronavirus disease 2019 COVID-19 is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic. The symptoms of COVID‑19 can vary but often include fever,[7] fatigue, cough, breathing difficulties, loss of smell, and loss of taste.[8][9][10] Symptoms may begin one to fourteen days after exposure …

Continue reading “Whales: Giants of the Ocean”