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Electric-assist bicycles (e-bikes) allow cyclists to travel at higher speeds and climb hills with less effort. Beyond average speed differences, little is known about the unique travel dynamics of e-bikes. The objective of this study is to examine systematic differences in speed and road grade dynamics between electric and conventional bicycle trips. Data were collected for 1451 utilitarian bicycle trips in Vancouver, Canada (10% on e-bikes). A subset of conventional bicycle trips were matched to the age, gender, purpose, and terrain characteristics of the e-bike sample. Biking schedules were constructed to represent the archetypal speed and grade dynamics of each set of trips. Results show that in addition to higher speeds, e-bike trips have significantly greater speed dynamics, substantially increasing the motive power and energy required for e-bike travel. Speed and grade dynamics are important aspects of microscopic cycling behaviour, with applications including vehicle design, facility design, and health evaluation.

Abstract Background The origin of animals from their unicellular ancestor was one of the most important events in evolutionary history, but the nature and the order of events leading up to the emergence of multicellular animals are still highly uncertain. The diversity and biology of unicellular relatives of animals have strongly informed our understanding of the transition from single-celled organisms to the multicellular Metazoa. Here, we analyze the cellular structures and complex life cycles of the novel unicellular holozoans Pigoraptor and Syssomonas (Opisthokonta), and their implications for the origin of animals. Results Syssomonas and Pigoraptor are characterized by complex life cycles with a variety of cell types including flagellates, amoeboflagellates, amoeboid non-flagellar cells, and spherical cysts. The life cycles also include the formation of multicellular aggregations and syncytium-like structures, and an unusual diet for single-celled opisthokonts (partial cell fusion and joint sucking of a large eukaryotic prey), all of which provide new insights into the origin of multicellularity in Metazoa. Several existing models explaining the origin of multicellular animals have been put forward, but these data are interestingly consistent with one, the “synzoospore hypothesis.” Conclusions The feeding modes of the ancestral metazoan may have been more complex than previously thought, including not only bacterial prey, but also larger eukaryotic cells and organic structures. The ability to feed on large eukaryotic prey could have been a powerful trigger in the formation and development of both aggregative (e.g., joint feeding, which also implies signaling) and clonal (e.g., hypertrophic growth followed by palintomy) multicellular stages that played important roles in the emergence of multicellular animals.