Tributes have been flowing in for one of New Zealand's most distinguished scientists, Sir Paul Callaghan.
Sir Paul, 64, had been suffering from colon cancer and died on Saturday.
A leader in the field of molecular physics, he was also a skilled communicator, using radio, books, and television to explain the relevance of science.[image:4860:half:right]
Acting Prime Minister Bill English says Sir Paul was "sheer brilliance" and was generous in sharing his ideas.
"He's been willing to use that brilliance to communicate with the wider public both about science and about New Zealand, and he did so with real integrity and some courage."
Mr English says even people who disagreed with Sir Paul deeply respected the way he talked and his motivations for his country.
Opposition leader David Shearer says Sir Paul's cutting edge research in the development of nuclear magnetic resonance methods has had an enormous impact in medicine, physics and biology.
He says Sir Paul was a brilliant scientist but also a very humble man.
"He was very down to earth, he was able to break down very complex ideas into very simple ones - a fantastic communicator."
The Prime Minister's chief science advisor, Sir Peter Gluckman, says Sir Paul made major contributions to the field of nanoscience.
He says Sir Paul's courage in telling the world about his battle with cancer was extraordinary, and even while he was terminally ill he was battling hard to promote a better New Zealand.
He says he was a giant of a person.
"He really made enormous contributions to New Zealand as a public intellectual, and we sadly have too few people like him."
The President of the Association of New Zealand Scientists, Shaun Hendy, worked with Sir Paul at Victoria University and Wellington's MacDiarmid Institute.
He says Sir Paul was an inspiration and a visionary, who championed science.
"He was an absolutely inspirational speaker. If you have had the chance to hear him speak you just don't forget it. He would hold the audience in the palm of his hand."
Academic career - Whanganui to Oxford
Born in Whanganui in 1947, Sir Paul was educated at Wanganui Boys' College and the Victoria University.
He won a Commonwealth Scholarship to Oxford University and took his doctorate there, working in low temperature nuclear physics.
On his return to New Zealand he took a lecturer post at Massey University and began researching an area of nanoscience.
He used nuclear magnetic resonance to probe complex fluids and soft matter, revealing how their atoms and molecules are organised on the tiniest scale.
After heading Massey's physics department, he moved to Victoria University of Wellington in 2001 as the Alan MacDiarmid Professor of Physical Sciences.
Gathering the best researchers from around the country to form the MacDiarmid Institute for Advanced Materials and Nanotechnology, he aimed to change the way science and technology help people understand the world.
"I think there is a cultural perspective that science brings which is very, very helpful," he said. "You can look at the world in a way that is not so frightening, not quite so overwhelming."
Sir Paul's methods were adopted worldwide in the production of plastics. Among other things, they helped dairy giant Fonterra develop the best mozzarella cheese for pizzas.
He founded a company, Magritek, manufacturing and exporting products based on his research. He wanted New Zealand to become a leader in high technology.
Sir Paul also took on a role in the education of the wider public, demystifying science. In the mid 2000s, he began a series of conversations exploring scientific questions with Kim Hill on Radio New Zealand National.
Some were edited into a book, As Far As We Know, that sold out in just over a month. He also presented a 10-part science and innovation television series.
As he explained in a Radio New Zealand interview, he wanted to articulate a higher vision for the physical sciences.
"What about trying to change the way we see how wealth could be generated in New Zealand, how we can improve our quality of life, through science and technology?
"By and large New Zealanders don't tend to think of themselves as being a science-driven or technology-driven country, and in many ways we are not to the degree to which I think we could be or should be."
Among the range of New Zealand and international awards in recognition of his work, he received in 2010 the prestigious Gunther Laukien Prize for groundbreaking work with radio waves to detect the motion of molecules, which had helped improve MRI brain scans.