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November 22 2013

TERRA 824: Life on Ice

Escape into spectacular Hyalite Canyon and discover the uniquely human activity of ice climbing. LIFE ON ICE is an adventure to remember; an adventure of impossible jumps through space and time; an adventure that blends art, science, and sport in a way that's never been seen before. Official Selection Big Bear Lake International Film Festival. Official Selection & Honourable Mention Wild Talk Africa International Film Festival. Produced by Refah Seyed Mahmoud.

November 14 2013

Science Podcast - Canine origins, asexual bacterial adaptation, perovskite-based solar cells, and more (15 Nov 2013)

The origin of dog domestication in Europe with Robert Wayne; Richard Lenski tracks the adaptation of bacteria over 50,000 generations; Robert Services describes the prospects of a new contender in solar technology.

April 02 2013

Ep. 288 Phases of Matter

As we quickly learn with water, matter can be in distinct phases: solid, liquid, gas and plasma; it all depends on temperature. But why do different materials require different temperatures? And what’s actually happening to the atoms themselves as the material switches phases?

February 16 2013

Science Podcast – Sweet Broccoli, Anxious Fish, Ancient Scat and more from ScienceNOW - AAAS Meeting [Feb 16, 2013]

Science NOW stories from the AAAS meeting, including why we should serve sweet veggies to kids, the effect of anti-anxiety drugs on fish, and the info ancient scat holds about climate change.

March 28 2012

How to get the most from your 60p first-class stamp – video

London's Science Museum provides some ingenious tips on how to put that pricey first-class stamp to work

With the announcement yesterday that the cost of a first-class stamp will soar to 60p at the end of the month – the biggest price rise for 37 years – Britons will need to think hard to squeeze the maximum value for money from every item they put in the post. To achieve the necessary efficiency savings, every letter, every package, every postcard, will have to do more work.

Inspiration is at hand in this wonderful educational video from London's Science Museum.

Whistling the theme tune from Postman Pat, a Royal Mail worker pushes a package through a letterbox on an industrial estate, triggering a seemingly endless train of energy transfers that starts with the sun and a magnifying glass lighting a fuse and finishes with a tank crushing a mechanical toy dog.

Along the way, potential energy is converted to kinetic energy and back again in a sequence worthy of Wallace and Gromit. There are nine glorious minutes of foaming, sawing, burning and floating, with each manifestation of energy transfer leading to the next. Eggs are broken, a venus flytrap snaps shut, a rocket rises into the air and hot tea melts through what appears to be a chocolate teacup.

And all for the price of a first-class stamp.

Our thanks to the ingenious people at Engineered Arts Ltd for this wonderful video, and to Guardian multimedia editor Jon Dennis for spotting it on the museum's website.


guardian.co.uk © 2012 Guardian News and Media Limited or its affiliated companies. All rights reserved. | Use of this content is subject to our Terms & Conditions | More Feeds


February 27 2012

02mydafsoup-01

[...]

Dix ans de retard. "Si on décale les courbes de la consommation du tabac, c'est-à-dire si on place en 1954 le début de fléchissement constaté à partir de 1964, on voit que 8 000 milliards de cigarettes "en trop" ont été consommées aux Etats-Unis. Elles n'auraient pas été fumées si le public avait su la vérité dix ans plus tôt, explique Robert Proctor. Cela représente environ huit millions de morts dans les décennies suivantes." Les mensonges d'une demi-douzaine de capitaines d'industrie provoquant la mort de plusieurs millions de personnes ? Une fiction qui mettrait en scène une conspiration de cette ampleur serait taxée d'irréalisme ou de loufoquerie...

Tout ne commence pas en décembre 1953. D'autres manoeuvres sont plus anciennes. Le plan Marshall, par exemple. Le grand programme d'aide à la reconstruction de l'Europe dévastée par la seconde guerre mondiale a également été "mis à profit par les cigarettiers américains pour rendre les populations européennes accros au tabac blond flue-cured, facilement inhalable". Tout est là. Le flue-curing est une technique de séchage des feuilles de tabac qui se répand largement aux Etats-Unis à la fin du XIXe siècle, et qui permet de rendre la fumée moins irritante, donc plus profondément inhalable. Or jusque dans la première moitié du XXe siècle, on fume encore, dans une bonne part de l'Europe continentale, du tabac brun, très âcre, beaucoup moins dangereux et addictif. Car plus la fumée peut pénétrer profondément dans les poumons, plus l'afflux de nicotine dans l'organisme est rapide, plus l'addiction qui se développe est forte. Et plus les dégâts occasionnés sur les tissus pulmonaires sont importants. "Au cours de la réunion de Paris (le 12 juillet 1947) qui a mis en mouvement le plan Marshall, il n'y avait aucune demande des Européens spécifique au tabac, raconte Robert Proctor. Cela a été proposé et mis en avant par un sénateur de Virginie. Au total, pour deux dollars de nourriture, un dollar de tabac a été acheminé en Europe."

[...]

Parfois, ce qu'on retrouve dans les cigarettes n'a pas été ajouté par les chimistes de l'industrie, mais par les caprices de la nature. Ainsi du polonium 210. Pour des raisons non encore éclaircies, la feuille de tabac a une détestable propriété : elle fixe et concentre cet élément radioactif naturellement présent dans l'environnement à des teneurs infimes. Les "tobacco documents" montrent que, dès les années 1950, l'industrie a découvert cette vérité qui dérange. Elle ne divulguera rien. Les premières publications indépendantes sur le sujet n'interviendront qu'au milieu des années 1960...

Golden Holocaust raconte par le menu comment les cadres de l'industrie ont réagi à ce "petit souci" de qualité du produit fini. Et le luxe de détails prodigués par les "tobacco documents" fait basculer dans un univers sidérant. Dans un premier temps, les cigarettiers cherchent à se débarrasser de cet élément radioactif. Ils font mener des travaux qu'ils gardent secrets. Car les publier pourrait "réveiller un géant endormi" ("waking a sleeping giant", dans le texte), écrit un cadre de Philip Morris à son patron, en 1978, ajoutant : "Le sujet va faire du bruit et je doute qu'il faille fournir des faits."

Plusieurs solutions sont découvertes. Changer d'engrais ? Traiter les feuilles de tabac à l'aide d'un bain d'acide ? Sélectionner les feuilles les moins chargées en polonium ? Aucune de ces solutions ne sera, semble-t-il, retenue. Car résoudre ce problème ne procure pas d'"avantage commercial ", selon l'expression d'un haut cadre de RJ Reynolds, consignée dans les documents. Le passage des feuilles de tabac par un bain acide, par exemple, contraindrait à une "gestion spécifique" d'effluents radioactifs. Cela coûte de l'argent.

[...]

Les conspirateurs du tabac | LeMonde.fr 2012-02-25

February 19 2012

October 13 2011

Stone Age painting kits found in cave

Bone and stone tools were apparently used for crushing pigments and mixing them in the shells of giant sea snails

The oldest known painting kits, used 100,000 years ago in the stone age, have been unearthed in a cave in South Africa.

Two sets of implements for preparing red and yellow ochres to decorate animal skins, body parts or perhaps cave walls were excavated at the Blombos cave on the Southern Cape near the Indian Ocean.

The stone and bone tools for crushing, mixing and applying the pigments were uncovered alongside the shells of giant sea snails that had been used as primitive mixing pots. The snails are indigenous to South African waters.

Other bones, including the shoulder blade of a seal, were among the ingredients for making the pigments. The bones were probably heated in a fire and the marrow fat used as a binder for the paint.

Along with ancient flakes of charcoal, researchers found a "high water mark" on the shells' inner wall, evidence that an unknown liquid, probably urine or water, was added to make the paint more fluid.

The remarkable discovery, reported in the journal Science, throws light on the capabilities and rituals of Homo sapiens who occupied the cave from at least 140,000 years ago. The cave's entrance was blocked by sand 70,000 years ago.

"This is the first known instance for deliberate planning, production and curation of a compound," Christopher Henshilwood at the University of Bergen told Science, adding that the finding also marked the first known use of containers. "It's early chemistry. It casts a whole new light on early Homo sapiens and tells us they were probably a lot more intelligent than we think, and capable of carrying out quite sophisticated acts at least 40,000 to 50,000 years before any other known example of this kind of basic chemistry," he added.

One of the toolkits, which was found next to a pile of different instruments, was more complex and particularly well preserved, with its intact shell coated with red pigment. A second shell, found close by, was broken, but its grinding stone was coated with red and yellow pigments, suggesting it had been used more than once.

Henshilwood's team said the tools were evidence for an "ochre-processing workshop" run by early humans, who gathered the colourful mineral oxides from sites about 20 miles away.

Piecing together the process from the instruments they found, Henshilwood said the artists used small quartzite cobbles to hammer and grind the ochres into a powder, which was then poured into the shell and mixed with charcoal, burnt and broken bone, and the unidentified liquid.

One of the artists' kits came with a slender bone from the front leg of a dog or wolf. One end of the bone had been dipped in ochre, leading the scientists to conclude it was used as a primitive paintbrush.

"You could use this type of mixture to prepare animal skins, to put on as body paint, or to paint on the walls of the cave, but it is difficult to be sure how it was used," said Francesco d'Errico, a study co-author at the University of Bordeaux. "The discovery is a paradox because we now know much better how the pigment was made than what it is used for."

Tiny grooves at the bottom of the shells may be scratch marks caused by sand grains when the artist mixed the paint with a finger. "From time to time they were scratching the bottom when their finger was moving some of these little grains," said d'Errico.

The team has unearthed other artefacts from early humans at the cave. In 2004, it uncovered a collection of 75,000-year-old decorative shell beads at Blombos cave, some of which had been painted with ochre.

"Twenty thousand years after these painting kits were left behind, humans at Blombos were certainly using pigments for symbolic purposes. It is clear they knew all the sources for these red and yellow pigments. This was a tradition for them," said d'Errico.


guardian.co.uk © 2011 Guardian News and Media Limited or its affiliated companies. All rights reserved. | Use of this content is subject to our Terms & Conditions | More Feeds


May 15 2011

Denis Glaser obituary

My husband, Denis Glaser, who has died of cancer aged 78, was a scientist who became a conceptual artist. Denis's extensive knowledge of materials and mechanics led to his daring and varied installations, which involved circular motion, water, video projection and sound. In the 1990s, he exhibited at many group shows and venues including the Barbican and Lisson Gallery in London, as well as in Düsseldorf, Caracas and Seoul.

Denis was born in London. He was evacuated during the second world war to live with an aunt in Argentina from the age of eight to 12. On his return to Britain, he attended William Ellis school in London. He graduated with a degree in chemistry from Oxford University in 1954 and spent the next 40 years working in the aircraft and motor industries.

He had made stoneware pottery and jewellery in his spare time and, in 1992, Denis changed direction to study fine arts at Middlesex University and Chelsea College of Art, where he gained his master's degree in 1997. Initially making figurative sculpture, Denis moved on to abstract installation art. His love of, and keen eye for, aesthetics was not his primary goal; he was far more concerned with expressing the conceptual and emotional meaning of his creations, often infused with memories.

At home in London, and at our retreat in Yorkshire, alongside being a hands-on father, Denis was perpetually engaged in DIY, ranging from plumbing, wiring, carpentry and machine and car repairs to building a harpsichord. Although reserved and often quiet in company, he was engaged in communal affairs, including our children's schools' governorship, chairing the neighbourhood association, local community radio and community action.

A secular, Liberal Jew, he nevertheless held some affection for Jewish tradition. His love of Israel led him in his later years to increasing concern about the actions of the Israeli government. He participated actively on the Board of Deputies of British Jews and with Jews for Justice for Palestinians.

Single-mindedly pursuing his various goals, typically on his bicycle, he was driven by a wish for minimum waste and maximum economy in time, resources and words: his written communications were telegraphic. Denis eschewed convention and formality but was scrupulously considerate and courteous.

He is survived by me, his children, Daniel, Michael and Eliane, and five grandchildren.


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February 14 2011

Van Gogh doomed his sunflowers

White powders that van Gogh added to brighten the yellows of his sunflowers triggered a reaction that turns the paint brown

When Vincent van Gogh moved to the south of France in the late 1880s, he began to paint sunflowers in vibrant chrome yellow. But even before his untimely death, some of his paintings had lost their sheen and started to turn brown.

The chemistry behind the discolouration has stumped conservationists, but using tiny flakes of paint and an enormous x-ray machine, scientists believe they finally know the cause of the problem.

Conservationists can slow down the degradation, for example by installing air-conditioning units to keep the paintings cool in the summer.

One enduring mystery was why some paintings that used chrome yellow turned brown while others were unaffected. The paintings that suffered most used yellow paint that had been lightened with white pigments.

The researchers found that sunlight kicks off a chemical reaction that ultimately turns yellow paint brown. The sunlight oxidises the oil in the paint, releasing electrons. These are then taken up by the yellow pigment – lead chromate – turning it green. The mix of green paint with oxidised oil produces a chocolate brown colour.

The team led by Koen Janssens at the University of Antwerp took samples of yellow chrome paint from left-over tubes belonging to 19th century artists. To simulate the effects of sunlight, they exposed them to UV light. After three weeks, paint from one of the artists, the Flemish Fauvist, Rik Wouters, had transformed from bright yellow to deep brown.

The team analysed flecks of the paint using an intense x-ray beam less than one thousandth of a millimetre wide at the European Synchrotron Radiation Facility in Grenoble. Those tests revealed that particles of lead chromate had been "reduced" – picking up extra electrons.

Further tests showed that the reaction only took place when white pigments based on sulphates were mixed into the yellow paint.

"By mixing these white powders in, van Gogh intended to make a lighter yellow paint, but through this effect, nature darkens it. While he wanted to show a light, pale and delicate yellow, it instead becomes a darker, brownish yellow," said Janssens.

Another series of tests on flakes of paint from two other van Gogh paintings, Bank of the Seine (1887) and View of Arles with Irises (1888) confirmed the same yellow-to-brown reaction had taken place.

The findings were published on Monday in the journal Analytical Chemistry.

Vincent van Gogh began painting in his late 20s and shot himself in 1890 at the age of 37 after completing more than 2,000 works of art.

Janssens said that paintings vulnerable to the discolouration could be preserved by reducing light levels and ensuring they do not get too warm in the summer, as heat accelerates the reaction.


guardian.co.uk © Guardian News & Media Limited 2011 | Use of this content is subject to our Terms & Conditions | More Feeds


Science Weekly podcast: The birds and the bees (X-rated version)

WARNING: this podcast contains frank information and graphic details about animal sex. Again.

Peter Atkins, professor of chemistry at Oxford University, goes right to the limits of science. We then take it a bit further as we look at some of the themes in his new book On Being which is out soon.

Peter is giving a lecture on the limits of science at the Royal Institution on 22 March.

We go behind the scenes at a new exhibition which is the X-rated version of the birds and the bees. They're all at it like rabbits.

Sexual Nature is at London's Natural History Museum. We've put together a beautiful audio slideshow to give you a flavour of the exhibition.

In our show-and-tell section, we discuss a study that has drawn up a geographical map of the incidence of allergies; a universal flu vaccine; plus the International Year of Chemistry - and why the discipline often gets overlooked.

Subscribe for free via iTunes to ensure every episode gets delivered. (Here is the non-iTunes URL feed).

Meet the Guardian's crack team of science bloggers:

The Lay Scientist by Martin Robbins
Life and Physics by Jon Butterworth
Punctuated Equilibrium by GrrlScientist
Political Science by Evan Harris

Follow the podcast on our Science Weekly Twitter feed and receive updates on all breaking science news stories from Guardian Science.

Email scienceweeklypodcast@gmail.com.

Guardian Science is now on Facebook. You can also join our Science Weekly Facebook group.

We're always here when you need us, listen back through our archive.



September 10 2010

The secret world of the microscopic

Gallery: Spike Walker is honoured for his 'outstanding contribution to photography and its application in the service of medicine'



February 03 2010

Notes and queries: Vincent van Gogh's bilingual letters to Theo

Vincent van Gogh's bilingual letters to Theo; A brief history of South Finchley; How to get the mix in a pill right

Vincent van Gogh and his brother Theo were Dutch, so why did they ­usually write to each other in French?

It is understandable to write in French when the alternative is double Dutch.

Brigid Browne, Calne, Wilts

The short answer is, they usually didn't. From Vincent's first surviving ­letter to Theo, written from The Hague on 29 September 1872, until he joined Theo in Paris in the early spring of 1886, the brothers corresponded in Dutch. When Vincent moved to Arles in the south of France in February 1888 he started writing to Theo in French, and Theo replied in kind. They wrote to each other in French from then on, until Vincent's death in July 1890. As to why – they were both living in France, speaking French every day, so it ­probably seemed more natural. 

Lynne Richards (translator, Van Gogh Letters), Seaford, East Sussex

Middlesex, Wessex, Sussex, Essex – what happened to Nossex?

If Nossex became Norfolk (N&Q, 27 January), why didn't Sussex become Suffolk?

Allan Ramsay, Buxton

I don't know about the missing South Finchley (N&Q, 27 January), but when it comes to Acton there's South, North, East, West, Central, Town and Mainline. Does any other place in the world have more stations named from it?

Roger Backhouse, Ilford

If you look on the map, East Finchley is South Finchley. There used to be three villages, North End (North Finchley), East End (East Finchley) and Church End (Finchley Central). Anyone born there still calls it Church End. My grandmother used to walk on paths ­between the three villages.

Jane O'Mahoney, Launceston, Cornwall

The history of these compass-point areas of London suburbs ­often lies in their transport development. North Finchley was the name given to a tram terminus, while the railway station at East Finchley was originally known as East End, Finchley; the company changed the name of the station, and thus of the suburb. This was a frequent process.

There is a West Finchley station but no South Finchley station. At Harrow, the District Railway built its station in Roxeth and named it South Harrow, while in the hamlet of Hooking Green the Metropolitan Railway called its ­station North Harrow. The same ­railway also coined West Harrow, but there has never been an East Harrow.

Michael J Smith, Derby

Where does the "curry" in to curry ­favour originate from?

The curry has nothing to do with Indian food – it comes from the Old French meaning "to prepare" or "to put in order". We retain it today when referring to the rubbing down and dressing of horses, as in curry-combing. Interestingly, the "favour" part of the phrase is a corruption of Favel, a chestnut horse in a 14th century French romance that became a symbol of cunning and duplicity; hence "to rub down Favel" meant to use the cunning that he personified, and to "curry favour" has come to mean to ingratiate oneself through ­obsequious behaviour.

Nader Fekri, Hebden Bridge, W Yorks

How do pill manufacturers ensure that the chemicals are evenly distributed? What percentage error, if any, is allowed?

They stir it, exactly the same as any cook. A properly made Christmas cake requires stirring, stirring, ­stirring, and when that includes ­particles of very different sizes – flour and sultanas – it is a harder task than mixing ­powders and crystals.

But just as a commercial cake ­manufacturer will use industrial-scale ­stirring, the science and technology of pharmacological stirring is quite a science. The enquirer should consult the Handbook of Industrial Mixing: Science and Practice.

John Davies, Haverbreaks, Lancaster

Why are there no female Formula One drivers?

I'd like to think it's because women have more sense, but I suspect it's because the racing fraternity couldn't handle being beaten by a woman.

Gordon Vassell, Hull

Because we have better things to do than drive round and round in circles.

Sue Rowlands, Chorlton, Ches

It couldn't have anything to do with Max Mosley, could it?

Geoffrey Rider, Ripon, N Yorks

Any answers?

Why are bad reviews more fun to read than good ones?

Phil Watts, London SE11

Did Genghis Khan know that what he was doing was wrong?

Edward Hubbard, Tamworth, Staffs

When did corks start to be used in wine bottles? What was used before cork?

Robin Reeves, London SW19

Send questions and answers to nq@guardian.co.uk. Please include name, address and phone number.


guardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds


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