The strange shapes seen in a rock from Mars that some researchers say are fossilised bacteria really are tiny micro organisms, say American researchers.But while they are confident the Mars rock contains fossilised life they cannot quite bring themselves to say it comes from the Red Planet, it might be Earthly contamination. Despite the uncertainty about their origin establishing that the small structures really were living things, and not just mineral globules, would be an advance in a field that has sharply divided opinions. "We conclude that the nanobodies that are so abundant in [the rock] are indeed nannobacteria. However whether these bodies originated on Mars, or are Antarctic contamination remains a valid question," say the researchers.
In 1780, an eccentric Frenchman, Professor Charles, an aerostats builder and a lecturer in physics at the Sorbonne had already made elementary photographs on paper impregnated with silver chloride by casting through sunlight the silhouette of a man. In this way, the image of the silhouette was engraved in white on the paper, but after a few moments the light started to have an effect on it again until it made it disappear. Researchers from the principle European countries embarked on a mission to see who would be the first to come up with a solution to the problem. James Watt in Scotland, the inventor of the steam engine, was one of them. But the weak images on silver solutions that he obtained with the camera obscura, disappeared very quickly. Wedgwood, and later Humphry Davy, persevered further, but still had no success. On these experiments Humphry Davy wrote: "What is needed is to somehow prevent the light parts of the drawing being affected by daylight. If this were achieved, the process would be as useful as it is straightforward. Up until now you have to keep the copy of the drawing in a dark place. This drawing can only be viewed in the dark and for a short time. I have tried in vain all possible means to prevent the colorless parts from going black with light. "As for the images produced by the camera obscura, undoubtedly they did not get enough light for me to obtain a clear drawing with the silver nitrate. Nonetheless this is where the research interest lies. But all attempts have been useless." It did not occur to Davy that the silver nitrate emulsion was not sufficiently sensitive to record the images that were being produced inside the camera. In 1805, in Ciudad Real, now known as San Cristóbal de las Casas, in Chiapas, Mexico–which was then part of Guatemala–Don Enrique Martínez, a chemistry and festive firework enthusiast, experimented with the camera obscura and a silver chloride solution applied to a metal plate. The local historian, Don Prudencio Esponda, describes Martínez's experiments in the following way: "With his mysterious dark box, the learned professor Martínez has managed to retain a replica, similar to a very beautiful drawing of the front of the temple of Santo Domingo, on a metal plate impregnated with chemical products which he invented. When he removed the above-mentioned replica from the dark, from the aforementioned box, he rubbed it with a compound of lime juice and other vegetable juices. In this way, the image lasted for some days during which the most important residents of the town could admire it." Don Enrique Martínez could not continue his interesting experiments, as in January 1806 he died in a terrible explosion accidentally set off in his firework factory. Nevertheless it was unlikely that even if he had continued to live, despite having made remarkable discoveries, that these should have become known, given that the distant province in which he lived was totally isolated from the important cultural centers. In 1822, Necèphore Niepce, a French chemist, succeeded in making the first permanent image employing silver iodide. Using a camera obscura bought from a manufacturer called Chevalier he achieved, after an eight-hour outside exposure, the image that from then on is known as the Set Table. source: From the Camera Obscura to Cinema - Carlos Jurado
A rather more convinced (although, I might add, not necessarily more convincing) version can be found over at Biblical Archaeology Review. first spotted over at the Collaboratory
"James (literally Jacob), son of Joseph, brother of Jesus."
The Antikythera mechanism was originally housed in a wooden box about the size of a shoebox with dials on the outside and a complex clockwork assembly of gears inscribed and configured to produce solar and lunar positions in synchronization with the calendar year. By rotating a handle on its side, its owner could read on its front and back dials the progressions of the lunar and synodic months over four-year cycles. The device has been estimated to be accurate to 1 part in 40,000.
The bronze gearing, remarkable enough on its own right, also contains a further innovation that would not be reinvented until the 19th century, the differential gear. The differential was used to calculate the phases of the moon by subtracting the moon's motion from that of the sun's. This level of sophistication allows us to say without fear of exaggeration that the Antikythera mechanism was an early kind of analog computer.
The device is also thought by some to have been able to model the motion of the five planets using the epicyclical model of planetary movement around a fixed earth devised by Apollonius of Perga and Hipparchus of Rhodes (later superceded by the heliocentric model of Copernicus).
It's been said that the Antikythera mechanism actually dropped and sank twice. The second submersion came after a comprehensive analysis of Antikythera mechanism was done by Derek de Solla Price (see Scientific American June 1959 and Gears from the Greeks: the Antikythera Mechanism: a Calendar Computer from ca. 80 B.C. 1975). Since then surprisingly little scholarly attention has been paid to what is surely the most exciting relic of advanced ancient technology that we have in our possession. After one hundred years, our estimation of the scientific and technology of the ancient Greeks needs to be be seriously revised.
"Suppose a traveller carried into Scythia or Britain the orrery recently constructed by our friend Poseidonius, which at each revolution reproduces the same motions of the sun, the moon, and the five planets that take place in the heavens every day and night, would any single native doubt that this orrery was the work of a rational being?"
-- Cicero reposted from the Collaboratory
Richard Dawkins defines "memes" as cultural replicators propagated through imitation, undergoing a process of selection, and standing to be selected not because they benefit their human carriers, but because of they benefit themselves. Are non-biological replicators such as memes theoretically possible? Yes, surely. The very idea of non-biological replicators, and the argument that the Darwinian model of selection is not limited to the strictly biological are already, by themselves, of theoretical interest. This would be so even if, actually, there were no memes. Anyhow, there are clear cases of actual memes, though much fewer than is often thought. Chain-letters, for instance, fit the definition. The very content of these letters, with threats to those who ignore them and promises to those who copy and send them, contributes to their being copied and sent again and again. Chain-letters don't benefit the people who copy them, they benefit their own propagation. Moreover, some chain-letters are doing better than others because of the greater effectiveness of their content in causing replication. Once the general idea of a meme is understood - and especially if it understood fairly loosely -, it is all too easy to see human social life as teeming with memes. Aren't, for instance, religious ideas, with their threats of hell for unbelievers and promises of paradise for the proselytes, comparable to chain-letters, and in fact much more effective in benefiting their own propagation, come what may to their human carriers? More generally, aren't words, songs, fashions, political ideals, cooking recipes, ethnic prejudices, folktales, and just about everything cultural, items that get copied again and again, with the more successful items managing to invade more minds over longer periods of historical time, and to recruit those minds to further their own propagation? If this were so, if culture were made of memes in Dawkins's strong sense, then the study of culture could - and arguably should - be recast as a science of memes or "memetics". The Darwinian model of selection could be used, with proper adjustments, to explain the properties, the variety and the evolution of culture, just as it explains the properties, the variety, and the evolution of life. The question is whether the claim that culture is made of memes is a true one. Several objections have been made to this claim. In his "foreword" to Susan Blackmore's The Meme Machine (1999), Richard Dawkins responds to the simplest and most serious objection: "that memes, if they exist at all, are transmitted with too low fidelity to perform a gene-like role in any realistically Darwinian selection process" (Dawkins 1999: x).1 I want here to discuss Dawkins's responses, and, in so doing, develop a different fundamental objection to the meme model.
The Mexican wave, or La Ola, which rose to fame during the 1986 World Cup in Mexico, surges through the rows of spectators in a stadium as those in one section leap to their feet with their arms up, and then sit down again as the next section rises to repeat the motion. To interpret and quantify this collective human behaviour, we have used a variant of models that were originally developed to describe excitable media such as cardiac tissue. Modelling the reaction of the crowd to attempts to trigger the wave reveals how this phenomenon is stimulated, and may prove useful in controlling events that involve groups of excited people. Using video recordings, we analysed 14 waves in football stadia holding over 50,000 people. The wave (Fig. 1) usually rolls in a clockwise direction and typically moves at a speed of about 12 metres (or 20 seats) per second and has a width of about 6-12 m (corresponding to an average width of 15 seats). It is generated by no more than a few dozen people standing up simultaneously, and subsequently expands through the entire crowd as it acquires a stable, nearlinear shape. Read on...
Neutron holography with atomic-scale resolution has been performed, for the first time, with an "inside-detector" approach.
Holography generally includes a source of illuminating waves, an object to be imaged, and a detector or film in which waves direct from the source interfere with waves scattered from parts of the object. The interference pattern, stored in the detector medium, is later read out (and a 3D image of the object viewed) by sending waves into the detector.
Holograms with visible light are common enough: they adorn most credit cards. Holograms using electrons (considered in their "wave" manifestation, not as particles) provide sharp pictures, but because the electrons cannot penetrate far into a solid sample, the imaging process is usually restricted to surface regions.
Holograms using x rays go can penetrate much farther, but their limitation consists of the fact that the penetration depth improves as the square of the atomic number. Therefore x-holography is not very good for materials with light elements.
Holograms with neutrons are different; rather than scattering from the electrons in the atoms of the sample, neutrons scatter only from nuclei, which are 100,000 times smaller than the atoms in which they reside. This is important when it comes time to reconstruct an image of the interior of a crystal lattice.
In an experiment carried out with a beam of neutrons from a reactor at the Institute Laue-Langevin in Grenoble, a group of scientists has produced, for the first time, an atomic-scale map of a crystal, in particular a sample of lead atoms, using a technique in which the "detector," a trace amount of atoms (cadmium-113) whose nuclei readily absorb neutrons, are embedded inside the sample itself.
The holographic process unfolds as follows: neutron waves can strike a Cd nucleus directly (reference beam) or by first scattering from a Pb nucleus. In either case, the absorption of a neutron stimulates a Cd nucleus to emit a high-energy photon observable in a nearby detector. The overall interference pattern for these two processes (absorbing scattered or direct neutron waves) is monitored as the profile of the sample to the beam is stepped through various angles.
The result: a crisp picture of a unit cell of 12 lead atoms (see figure). This process should be great for spotting foreign atoms in a solid (dopants if the atoms are desired, impurties if they're not).
Since the neutron has a magnetic moment, n-holography might also contribute to an understanding of the magnetic nature of the sample atoms, in addition to imaging their whereabouts. (Cser et al., Physical Review Letters, 21 October 2002; contact Laszlo Cser, Central Research Institute for Physics, Budapest, email@example.com, 36-1-392-2222 extension 1526.)
from the Ramayana - according to the sage Valmiki "At Rama's command, those lions among the monkeys entered the mighty forest with alacrity in hundreds and thousands on every side and those leaders on the simian tribes, tearing up the rocks, which in size they resembled, and the trees also dragged them to the sea and they covered the ocean with Sala, Ashvararna, (list of tree names).Those foremost monkeys transported those trees, with or without roots, bearing them like so many standards of Indra (the king of heaven) and they heaped (list of tree names) here and there. With the aid of mechanical devices, those powerful colossi dug up stones as big as elephants and rocks, and the water suddenly spouted into the air only to fall instantly. Thereafter those monkeys churned up the sea by rushing into it on all sides pulling on the chains. "That immense causeway constructed by Nala in the bosom of the sea was built by the arms of those monkeys of formidable exploits and it extended over a hundred leagues. "Some brought trunks of trees and others set them up; it was by hundreds and thousands that those monkeys, like unto giants, made use of reeds, logs and blossoming trees to construct that bridge, rushing hither and thither with blocks of stone resembling mountains or the peaks of crags, which, flung into the sea, fell with a resounding crash. "The first day those monkeys resembling elephants, or immense energy, full of high spirits and exceedingly merry, erected fourteen leagues of masonry. The second day, those highly active monkeys of formidable stature set up twenty leagues. Bestirring themselves, those giants threw twenty-one leagues of structure over the ocean on the third day and on the fourth, working feverishly, they built up twenty-two leagues in extent. The fifth day, those monkeys, industrious workers, reached to twenty-three leagues distance from the further shore. "That fortunate and valiant son of Vishvakarma (architect of the demigods), leader of the monkeys, constructed a causeway worthy of his sire over the ocean and that bridge erected by Nala over the sea, the haunt of whales, dazzling in its perfection and splendor, was like the constellation of Svati in space. "Then the gods, Gandharvas, Siddhas (living beings superior to humans) and supreme Rishis (great sages) assembled in the sky, eager to see that masterpiece, and the gods and Gandharvas gazed on that causeway, so difficult of construction, that was ten leagues in width and a hundred in length built by Nala.
"Those monkeys thereafter dived, swam and shouted at the sight of that unimaginable marvel that was almost inconceivable and caused one to tremble! And all beings beheld that causeway thrown over the ocean and by hundreds and thousands of kotis (millions), those monkeys, full of valor, having built that bridge over the immense repository of waters, reached the opposite shore. "Vast, well-constructed, magnificent with its wonderful paved floor, solidly cemented, that great causeway like unto a line traced on the waves, resembled the parting of a woman's hair. "Meanwhile Bibishana (brother of Ravana who joined Rama), mace (club) in hand, held himself ready at his post with his companions in case of an enemy attack. Thereafter Sugriva addressed Rama, who was valiant by nature, saying "Mount on the shoulders of Hanuman and Laxmana (brother of Rama) on those of Angada. O Hero, vast is this ocean, the abode of whales; those two monkeys who freely range the sky will transport you both." "Then the fortunate Rama and Laxmana advanced thus and that magnanimous archer was accompanied by Surgriva. Some monkeys strode forward in the center, some threw themselves into the waves, some sprang into the sky, others marched on the bridge, some ranged through space like birds, and the terrific tumult of the trampling of that formidable army of monkeys drowned the roar of the ocean. "When those simian troops had passed over the sea by the grace of Nala's causeway, the king ordered them to camp on the shore which abounded in roots, fruits and water. At the sight of that masterpiece that had materialized under the command of Raghava (another name of Lord Rama), despite the difficulties, the gods, who had drawn near with the Siddhas and Charanas as also the great Rishis, anointed Rama in secret there, with water form the sea, and said: "Mayest thou be victorious over thy foes, O Thou, who are a God among men! Do Thou rule over the earth and the sea eternally!" Thus in various auspicious words, did they acclaim Rama in the midst of the homage offered to him by the Brahmins."
All the monkeys sent to the South in search of Sita now returned to Rama. Unspeakable was his joy when he heard Sita was alive and waiting for him. He pressed Sita's jewel, which she had worn so many times in the happy days, to his heart, and embraced Hanuman as a reward for all that he had done. The army of monkeys, which had been increased by a host of bears, started at once on their march to the Coast of the Indian Ocean. Arrived there the difficulty arose how to cross the Ocean to Lanka, for Hanuman was the only one who could do that without a bridge. One of the brothers of Ravana, Vibhishana, who had left him, because Ravana had not followed his advice to release Sita, had come to Rama's camp as a friend. As he was acquainted with the difficulties of crossing the Ocean he advised Rama, first to ask permission of the presiding Deva of the Ocean and then build a bridge over it. The monkey, Nale, the son of the mighty Deva Architect, Vishwakarma, who was very skilful in the building of bridges, had to undertake this difficult task. All the monkeys and bears were set to work. They had to take on their huge forms, for it was no easy task to loosen and roll huge rocks into the Ocean. This was the work for the monkeys. And oh! how they jumped and pulled and rolled and plunged the rocks into the sea. The bears had to fell big trees and lay them over the rocks. And then again the big monkeys filled up the spaces with crags and stones and sand and the bridge building went on very fast, for they worked for dear life. Hanuman was always the foremost one, and he always carried the biggest loads. Besides he was an excellent jester, and when some of the weaker workers felt tired, he made such a lot of fun, that they were soon ready to go on again with their work. So Hanuman made himself very useful and he became the favourite of the whole army. On they worked hard, and note! they did it so quickly, that in five days the bridge reached the shores of Lanka. And it was such a firm and strong bridge that the whole army of monkeys and bears, with Rama, Lakshmana and Vibhishana crossed the Ocean safely and stepped on Lanka's shore, where the unhappy Sita had been mourning and waiting for over ten weary months. They marched at once to the Capital and surrounded it. As spies had already carried the news to Ravana of the approach of the strange army, he fortified his Capital and awaited their attack. ["Oh, mother dear, was the bridge which the monkeys built, Adam's Bridge?" asked one of the listeners quite excitedly. "Yes dear! What remains now of the monkey's bridge is called Adam's Bridge. At the time they built it, long, long ago, it was named 'Rama's Bridge'." "There is yet an Island near Adam's Bridge which is called Ramasvaram, on which a beautiful Temple has been built over an old Shrine of Siva, and is supposed to have been erected by Rama when he was crossing the bridge. " "Here the people still talk of the brave deeds of Rama and the faithfulness of Sita, and thousands of Hindus make pilgrimages there up to this day."]Short stories from the History of Ceylon by Marie Musaeus-Higgens 1909