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- Public domain: Paul Valery
- Free course: The Library of Alexandria
- Sharks: more nose than jaws
- The Himalayas keep growing
Lead author Dr John Elliott of Oxford University, a member of the COMET [UK Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics] team, said: 'Nepal has some of the highest mountain ranges in the world that have been built up over millions of years because of the collision of India with Asia. But the way in which mountains grow and when this occurs is still debated.
'We have shown that the fault beneath Nepal has a kink in it, creating a ramp 20km underground. Material is continually being pushed up this ramp, which explains why the mountains were seen to be growing in the decades before the earthquake.
'The earthquake itself then reversed this, dropping the mountains back down again when the pressure was released as the crust suddenly snapped in April 2015.
'Using the latest satellite technology, we have been able to precisely measure the land height changes across the entire eastern half of Nepal. The highest peaks dropped by up to 60cm in the first seconds of the earthquake.'
The time of year, and the law of averages, means that some of you reading this will be suffering from a miserable head cold right now. You have our sympathies, but - on the bright side - at least you're not a shark. When they get a blocked nose, it doesn't just render them miserable - it can stop them finding their way about. New research just published in PLOS has found evidence that sharks use their noses to smell microscopic changes in chemicals in the sea, and use that to guide themselves across the oceans:
How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.
How can we know about events which happened in antiquity? It's hard enough to understand what happened a few weeks ago; how do you gain an understanding of events which happened centuries before living memory? That's one of themes explored by this free course:
[A]fter reading the extract from Bagnall, you will have seen that asking ‘how we know what we know’ about the library of Alexandria means acknowledging that we actuallyknow very little. This uncertainty only deepens when we turn to consider its eventual fate. It’s obvious that, at some point in history, the library disappeared; but how? If you are seduced by the idea of the library as a storehouse of universal knowledge, then take a moment to imagine what it would mean for all the world’s books to be lost – or even destroyed. What could possibly lead to such a calamity, and what would its effects be? Even if you take the more moderate (and, to my mind, plausible) view, that the library could not possibly have been ‘universal’, but was at least a very large and ambitious scholarly collection, then you are still likely to be curious about what happened to it, and to lament the disappearance of texts that it might once have contained. The stories that are told about the end of the library of Alexandria are therefore a very important part of how we interpret it.
This week, we're focusing on some of the artists and writers whose work entered the public domain at the start of the year. Yesterday, we met David Young Cameron. Today, we turn to Paul Valéry.
Valéry was a French poet and author. Born in 1871, he came to writing by a circuitous route - he studied law and worked as a private secretary before finally settling to concentrate on his art.
His great work is La Jeune Parque. This 500 word poem explores the turmoil of Clotho, one of the fates, as she attempts to decide between the power of imortality and the life of a mortal. Beyond this, he published little poetry; much of his work was prose-based - a commentary on life often taking a cynical perspective. His notebooks - the Cahiers - have been published and acclaimed, especially amongst fans of constructivist epistemology.
He was elevated to become a member of the Acadamie Francais in 1942, but although nominated for a Nobel Prize on a dozen occasions, never won that particular honour.
Valéry's refusal to collaborate with the Vichy Regime during the Second World War saw him attacked by the puppet French state; the faux-government's attempts to humiliate him into compliance by stripping him of work and honours failed to shift him. He oulasted the regime, but died on July 20th 1945.