"What would the world be if there were no hunger?" It's a question that Professor Crystal would ask her students. They found it hard to answer, she wrote later, because imagining something that isn't part of real life—and learning how to make it real—is a rare skill. It is taught to artists and engineers, but much less often to scientists. Crystal set out to change that, and helped to create a global movement. The result一an approach known as systems thinking—is now seen as essential in meeting global challenges.

Systems thinking is crucial to achieving targets such as zero hunger and better nutrition because it requires considering the way in which food is produced, processed, delivered and consumed, and looking at how those things intersect (交叉) with human health, the environment, economics and society. According to systems thinking, changing the food system—or any other network- requires three things to happen. First, researchers need to identify all the players in that system, second, they must work out how they relate to each other, and third, they need to understand and quantify the impact of those relationships on each other and on those outside the system.

Take nutrition. In the latest UN report on global food security, the number of undernourished (营养不良) people in the world has been rising, despite great advances in nutrition science. Tracking of 150 biochemicals in food has been important in revealing the relationships between calories, sugar, fat and the occurrence of common diseases. But using machine learning and artificial intelligence, some scientists propose that human diets consist of at least 26,000 biochemicals—and that the vast majority are not known. This shows that we have some way to travel before achieving the first objective of systems t hinking - which,in this example, is to identify more constituent parts of the nutrition system.

A systems approach to creating change is also built on the assumption that everyone in the system has equal power. But as some researchers find, the food system is not an equal one. A good way to redress (修正) such power imbalance is for more universities to do what Crystal did and teach students how to think using a systems approach.

More researchers, policymakers and representatives from the food industry must learn to look beyond their direct lines of responsibility and adopt a systems approach. Crystal knew that visions alone don't produce results, but concluded that "we'll never produce results that we can't envision".

Human speech contains more than 2, 000 different sounds, from the common "m" and "a" to the rare clicks of some southern African languages. But why are certain sounds more common than others? A ground-breaking, five-year study shows that diet-related changes in human bite led to new speech sounds that are now found in half the world's languages.

More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals, such as "f" and "v", were more common in the languages of societies that ate softer foods. Now a team of researchers led by Damián Blasi at the University of Zurich, Switzerland, has found how and why this trend arose.

They discovered that the upper and lower front teeth of ancient human adults were aligned (对齐), making it hard to produce labiodentals, which are formed by touching the lower lip to the upper teeth. Later, our jaws changed to an overbite structure(结构), making it easier to produce such sounds.

The team showed that this change in bite was connected with the development of agriculture in the Neolithic period. Food became easier to chew at this point. The jawbone didn't have to do as much work and so didn't grow to be so large.

Analyses of a language database also confirmed that there was a global change in the sound of world languages after the Neolithic age, with the use of "f" and "v" increasing remarkably during the last few thousand years. These sounds are still not found in the languages of many hunter-gatherer people today.

This research overturns the popular view that all human speech sounds were present when human beings evolved around 300, 000 years ago. "The set of speech sounds we use has not necessarily remained stable since the appearance of human beings, but rather the huge variety of speech sounds that we find today is the product of a complex interplay of things like biological change and cultural evolution," said Steven Moran, a member of the research team.

Theatres and Entertainment

St David's Hall

St David's Hall is the award winning National Concert Hall of Wales standing at the very heart of Cardiff's entertainment centre. With an impressive 2,000-seat concert hall, St David's Hall is home to the annual Welsh Proms Cardiff. It presents live entertainment, including pop, rock, folk, jazz, musicals, dance, world music, films and classical music.

The Hayes, Cardiff CF10 1AH

www.stdavidshallcardiff.co.uk

The Glee Club

Every weekend this is "Wales" premier comedy club where having a great time is the order for both audiences and comedy stars alike. It is hard to name a comedy star who hasn't been on the stage here. If you are looking for the best comedies on tour and brilliant live music, you should start here.

Mermaid Quay, Cardiff Bay, Cardiff CF10 5BZ

www.glee.co.uk/cardiff

Sherman Cymru

Sherman Cymru's theatre in the Cathays area of Cardiff reopened in February 2012. This special building is a place in which theatre is made and where children, artists, writers and anyone else have the opportunity (机会) to do creative things. Sherman Cymru is excited to present a packed programme of the very best theatre, dance, family shows and music from Wales and the rest of the world.

Senghennydd Road, Cardiff CF24 4YE

www.shermancymru.co.uk

New Theatre

The New Theatre has been the home of quality drama, musicals, dance and children's shows for more than 100 years. Presenting the best of the West End along with the pick of the UK's touring shows, the New Theatre is Cardiff's oldest surviving traditional theatre. Be sure to pay a visit as part of your stay in the city.

Park Place, Cardiff CF10 3LN

www.newtheatrecardiff.co.uk