Mars is back. Suddenly everyone from Elon Musk to Ridley Scott to Donald Trump is talking about going to the Red Planet.When the Apollo astronauts walked on the Moon in 1969, many people imagined Mars would be next. However, NASA’s Viking 1, which landed in 1976, was just...
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All the matter and light we can see in the universe makes up a trivial 5 per cent of everything. The rest is hidden. This could be the biggest puzzle that science has ever faced. Since the 1970s, astronomers have been aware that galaxies have far too little...
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On 14 September 2015, after 50 years of searching, gravitational waves were detected for the first time and astronomy changed for ever. Until then, investigation of the universe had depended on electromagnetic radiation: visible light, radio, X-rays and the rest. But gravitational waves- ripples in the fabric of...
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Focusing on contemporary and historical developments in the study of human anatomy, Eyewitness: Human Body features clear, age appropriate text, photographs, charts, graphics, and 3-D models highlighting the inner workings of our bodies — from the framework of our skeleton to the millions of tiny cells that make...
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For centuries, economics was dominated by the idea that we are rational individuals who optimise our own ‘utility’. Then, in the 1970s, psychologists demonstrated that the reality is a lot messier. We don’t really know what our utility is, and we care about people other than ourselves. We...
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This is a condensed version of Logic, Third Edition, by Stan Baronett, containing chapters 1, 3, 4, 5, 6, 7, and 8 from the main text. Featuring an exceptionally clear writing style and a wealth of real-world examples and exercises, Logic, Third Edition, shows how logic relates to...
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Cambridge – Active Grammar – Book (with key) + CD (level 3) Download http://usafiles.net/2gUu/Language_Centre__Active_grammar_3.pdf http://usafiles.net/10zT/Active_Grammar_3_CD-ROM.zip
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Cambridge – Active Grammar – Book (with key) + CD (level 1) Download http://usafiles.net/10zP/Newson_39_s_Language_Centre_-_Active_grammar_1.pdf http://usafiles.net/10zQ/Active_Grammar_1_CD-ROM.zip
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Oxford – Test It Fix It Download http://usafiles.net/10zN/Test_it_Fix_it_-_Verbs_and_Tenses_Pre-Interme.pdf http://usafiles.net/10zO/test_it_fix_it_english_verbs_and_tenses_kenna_bourke.pdf
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