CASTEL member Paul van Kampen has published two articles in the Physical Review Physics Education Research journal this month, with co-authors from KU Leuven, on students’ understanding of two-variable calculus concepts in mathematics and physics contexts. The first article “Students’ understanding of two-variable calculus concepts in mathematics and physics contexts. I. The partial derivative and the directional derivative” is available here. The second article “Students’ understanding of two-variable calculus concepts in mathematics and physics contexts. II. The gradient and the Laplacian” is available here.