Rapunzel, Rapunzel, put up your hair



LONDON // British scientists said a "Rapunzel number" may have helped them to crack a problem that has perplexed humanity since Leonardo da Vinci pondered it 500 years ago.

Scientists from the University of Cambridge and the University of Warwick said they had devised a "ponytail shape equation" that when calculated using the Rapunzel number and a measure of the curliness of hair could be used to predict the shape of any ponytail.

Cambridge's Professor Raymond Goldstein said he and his colleagues took account of the stiffness of individual hairs, the effects of gravity and the average waviness of human hair to come up with their formula.

The Rapunzel Number provides a key ratio needed to calculate the effects of gravity on hair relative to its length.

"That determines whether the ponytail looks like a fan or whether it arcs over and becomes nearly vertical at the bottom," Prof Goldstein said.

The research also took into account how a bundle of hair is swelled by the outward pressure that arises from collisions between the component hairs.

Scientists said the work has implications for understanding the structure of materials made up of random fibres, such as wool and fur, and will have resonance with the computer graphics and animation industry, where the representation of hair has been a challenging problem.

"Our findings extend some central paradigms in statistical physics and show how they can be used to solve a problem that has puzzled scientists and artists ever since Leonardo da Vinci remarked on the fluid-like streamlines of hair in his notebooks 500 years ago," Prof Goldstein said.

The research was conducted by Prof Goldstein, Professor Robin Ball from the University of Warwick and their colleagues. It is to be presented to the American Physical Society in Boston on February 28.

* Reuters

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Skewed figures

In the village of Mevagissey in southwest England the housing stock has doubled in the last century while the number of residents is half the historic high. The village's Neighbourhood Development Plan states that 26% of homes are holiday retreats. Prices are high, averaging around £300,000, £50,000 more than the Cornish average of £250,000. The local average wage is £15,458. 

The smuggler

Eldarir had arrived at JFK in January 2020 with three suitcases, containing goods he valued at $300, when he was directed to a search area.
Officers found 41 gold artefacts among the bags, including amulets from a funerary set which prepared the deceased for the afterlife.
Also found was a cartouche of a Ptolemaic king on a relief that was originally part of a royal building or temple. 
The largest single group of items found in Eldarir’s cases were 400 shabtis, or figurines.

Khouli conviction

Khouli smuggled items into the US by making false declarations to customs about the country of origin and value of the items.
According to Immigration and Customs Enforcement, he provided “false provenances which stated that [two] Egyptian antiquities were part of a collection assembled by Khouli's father in Israel in the 1960s” when in fact “Khouli acquired the Egyptian antiquities from other dealers”.
He was sentenced to one year of probation, six months of home confinement and 200 hours of community service in 2012 after admitting buying and smuggling Egyptian antiquities, including coffins, funerary boats and limestone figures.

For sale

A number of other items said to come from the collection of Ezeldeen Taha Eldarir are currently or recently for sale.
Their provenance is described in near identical terms as the British Museum shabti: bought from Salahaddin Sirmali, "authenticated and appraised" by Hossen Rashed, then imported to the US in 1948.

- An Egyptian Mummy mask dating from 700BC-30BC, is on offer for £11,807 ($15,275) online by a seller in Mexico

- A coffin lid dating back to 664BC-332BC was offered for sale by a Colorado-based art dealer, with a starting price of $65,000

- A shabti that was on sale through a Chicago-based coin dealer, dating from 1567BC-1085BC, is up for $1,950

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