91av

Crossword No20

ACROSS

1 Medium-sized antelope of southern Africa (6)

5 Science-fiction “Supermarionation” series first shown in 1964 (8)

9 Electromagnetic radiation with wavelengths longer than those of visible light (8)

10 Seismic movement (6)

11 Psychedelic compound found in some mushrooms (10)

12 Location on the world wide web; place of archaeological exploration (4)

13 2017 book on women and science by Angela Saini (8)

16 Term for a self-sustainable automaton with limited environmental impact (6)

17 Abnormally folded, protease-resistant infectious agents (6)

19 Benjamin ___ (1706–90), US statesman and inventor of the lightning rod (8)

21 In electronics, an integrated circuit (4)

22 The number of protons and neutrons in an atomic nucleus (4,6)

25 Never __ __, 1980 biography of Sir Isaac Newton (2,4)

26 Apparent path of the sun, as seen from Earth (8)

27 Computer programs that may be used at no cost (8)

28 Method of sound reproduction that simulates multidirectional perspective (6)

DOWN

2 Prehensile appendages found at the ends of primate forelimbs (5)

3 See 24

4 Home city of the NED University of Engineering & Technology and the Dow University of Health Sciences (7)

5 In computing, a graphical element positioned off-centre in a window or on a desktop (7)

6 ___ pulsed light, type of skin therapy (7)

7 “What you do is trial and error, experimentation, ___” – Paul Halmos, on mathematics (9)

8 In logic, term describing an argument based upon existing confidence in a related proposition (1,8)

14 Polaris (5,4)

15 Low-density outer layer of a planet’s atmosphere (9)

18 Island home of the orangutan Pongo abelii (7)

19 In photography, an ultra-wide-angle lens (7)

20 The ring-shaped region bounded by two concentric circles (7)

23 Tree of the genus Acer (5)

24/3 French mathematician and founder of the Paris Institute of Statistics (1871–1956) (5,5)