The heart is a fist-sized organ in the chest that is responsible for pumping blood. It has four chambers: two upper chambers (atria) and two lower chambers (ventricles). These chambers are separated ...

On the side of the coin on the left are the busts of two men facing right, side by side, both men have tendrils of short curly hair with headbands around their heads, shoulders draped in loose ...

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond ...

IT is somewhat strange that in the article on Ptolemy in the “Penny Cyclopædia,” he is spoken of only as a geographer. His fame is undoubtedly built upon his two great works on astronomy and ...

These drawings, which first appeared in the journal Advances in Protein Chemistry in 1981, became known as ribbon diagrams. Richardson’s drawing style was quickly adopted. Structural biologists ...

Inspired by professor of climate science Ed Hawkins' climate warming stripes, the air quality stripes depict particulate matter (PM) concentrations in 176 cities worldwide since 1850. These tiny ...

Female anatomy includes the internal and external structures, including those responsible for hormones, reproduction, and sexual activity. The female reproductive system is essential for hormone ...

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After introducing Porphyry’s commentary, this chapter asks how Porphyry saw himself at the time of writing. Was it as a ‘Neoplatonist’ and pupil of Plotinus as usually presumed? Does he write as a ...