Academics at universities worldwide have taken part in the ice bucket challenge, the social media trend aimed at raising money and awareness of amyotrophic lateral sclerosis, a form of motor neurone disease.

On Tuesday the Motor Neurone Disease Association posted a YouTube video of Stephen Hawking, professor of cosmology at the University of Cambridge, taking part in the challenge. Professor Hawking has suffered from ALS since the age of 21. It is a neurodegenerative disease that affects muscle function.

In the video Professor Hawking says ¡°I support the ALS Ice Bucket Challenge in support of the MNDA ¨C the Motor Neurone Disease Association¡±.

But he adds that because he had pneumonia last year, ¡°it would not be wise for me to have a bucket of cold water poured over me. But my children Robert, Lucy and Tim gallantly volunteered to take the challenge for me. I urge everyone to donate to the MNDA to eliminate this terrible disease.¡±

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Participants of the challenge are invited to donate to an ALS charity of their choice and film themselves pouring a bucket of cold water over their head before posting their video to social media nominating others to take part.

Sir Leszek Borysiewicz, Cambridge¡¯s vice-chancellor, was quick to accept the nomination extended to him in Professor Hawking¡¯s video. He went on to nominate the chief executive of the Wellcome Trust, the chief executive of the Medical Research Council and the chief executive of the MRC Molecular Biology Laboratory in Cambridge.

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In recent days academics from institutions across the world have taken part in the craze. On Friday 40 researchers at the University of Sheffield undertook the challenge after receiving nominations from the Katholieke Universiteit Leuven in Belgium and Western University in Ontario, Canada. They have nominated staff at the University of Sydney, King¡¯s College London and Trinity College Dublin.

In the US college presidents are also taking on the challenge. Donna E. Shalala of the University of Miami was doused in ice cold water at an event for incoming undergraduate students. The presidents of Harvard University, the University of Notre Dame and the University of Connecticut are also among those who have taken part.