Silicene pops out of the plane - physicsworld.com
"Researchers in Japan say that they have made 2D honeycomb crystals of silicon that resemble the carbon-based material graphene. This is the second potential sighting of the material dubbed "silicene"; the other was reported in April by an independent group in Europe. The Japanese research suggests it may be relatively easy to alter the structure of silicene by changing the substrate on which it is grown – which could allow different versions of silicene to be produced with a range of useful electronic properties. However, not all scientists agree that this latest material is actually silicene."
Thursday, June 21, 2012
Tuesday, June 19, 2012
Arles, Turin and Caesar
The heart of the ancient history of Arles, this is what is on show at the Louvre Museum of Paris, until 25 June 2012. The Museum is hosting an exhibition of spectacular Roman pieces recovered from the bottom of the Rhone! From March 9 to June 25, 2012, the Louvre Museum in Paris
On exhibition fifty of the most spectacular artifacts unearthed by archaeologists: columns and capitals, fragments of statues and reliefs, Roman jewelery, lamps, vases ... These pieces are coming from the museum of Arles, and other pieces from Avignon, Vienne and Turin.
Among the pieces from Turin, you can admire Julius Caesar's bust, unearthed in 1825, long considered unique, until the discovery in 2007 in Arles of another bust of the Roman politician. At the Louvre, these sculptures will be presented for the first time side by side.
http://www.france.fr/it/arti-e-cultura/evenement/arles-gli-scavi-del-rodano-un-fiume-memoria
Arles
Torino
Napoli
On exhibition fifty of the most spectacular artifacts unearthed by archaeologists: columns and capitals, fragments of statues and reliefs, Roman jewelery, lamps, vases ... These pieces are coming from the museum of Arles, and other pieces from Avignon, Vienne and Turin.
Among the pieces from Turin, you can admire Julius Caesar's bust, unearthed in 1825, long considered unique, until the discovery in 2007 in Arles of another bust of the Roman politician. At the Louvre, these sculptures will be presented for the first time side by side.
http://www.france.fr/it/arti-e-cultura/evenement/arles-gli-scavi-del-rodano-un-fiume-memoria
Arles
Torino
Un altro ritratto interessante รจ quello del busto Farnese, a Napoli
Napoli
Thursday, June 14, 2012
Blackwood and Lovecraft
Of such great powers or beings there may be conceivably a survival... a survival of a hugely remote period when... consciousness was manifested, perhaps, in shapes and forms long since withdrawn before the tide of advancing humanity... forms of which poetry and legend alone have caught a flying memory and called them gods, monsters, mythical beings of all sorts and kinds...
These words written by Algernon Blackwood introduce the The Call of Cthulhu, by H. P. Lovecraft.
"The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age."
Tuesday, June 12, 2012
Ancient Rainfall, Carved in Stone
"Stalactites grow from cave ceilings not as dull cones but often sporting elegant corrugations. In Physical Review Letters, two Italian researchers now explain these mysterious, wavy patterns using standard fluid mechanics. Their theory shows that the horizontal ripples form because spatially periodic patterns arise in the rate of mineral deposits from the water flowing down the stalactite. Starting from this model, climate scientists might in the future use stalactite surface structure to reconstruct variations in precipitation patterns over tens of thousands of years."
Ancient Rainfall, Carved in Stone
Ancient Rainfall, Carved in Stone
Friday, June 1, 2012
NGC 891
Another superb image at http://apod.nasa.gov/apod/ap120526.html
" This sharp cosmic portrait features NGC 891. .. At first glance, it has a flat, thin, galactic disk and a central bulge cut along the middle by regions of darkobscuring dust. The combined image data also reveal the galaxy's young blue star clusters and telltale pinkish star forming regions. And remarkably apparent in NGC 891's edge-on presentation are filaments of dust that extend hundreds of light-years above and below the center line. The dust has likely been blown out of the disk by supernova explosions or intense star formation activity. "
" This sharp cosmic portrait features NGC 891. .. At first glance, it has a flat, thin, galactic disk and a central bulge cut along the middle by regions of darkobscuring dust. The combined image data also reveal the galaxy's young blue star clusters and telltale pinkish star forming regions. And remarkably apparent in NGC 891's edge-on presentation are filaments of dust that extend hundreds of light-years above and below the center line. The dust has likely been blown out of the disk by supernova explosions or intense star formation activity. "
Transit of Mercury
Very beautiful image at http://apod.nasa.gov/apod/ap120527.html Image Credit: SOHO - EIT Consortium, NASA
"The diminutive disk of Mercury, the solar system's innermost planet, spent about five hours crossing in front of the enormous solar disk in 2003 ... the horizon was certainly no problemfor the sun-staring SOHO spacecraft. Seen as a dark spot, Mercury progresses from left to right (top panel to bottom) in these four images from SOHO's extreme ultraviolet camera. The panels' false-colors correspond to different wavelengths in the extreme ultraviolet which highlight regions above the Sun's visible surface."
"The diminutive disk of Mercury, the solar system's innermost planet, spent about five hours crossing in front of the enormous solar disk in 2003 ... the horizon was certainly no problemfor the sun-staring SOHO spacecraft. Seen as a dark spot, Mercury progresses from left to right (top panel to bottom) in these four images from SOHO's extreme ultraviolet camera. The panels' false-colors correspond to different wavelengths in the extreme ultraviolet which highlight regions above the Sun's visible surface."
Here the image from NASA after processing with IRIS
Transit of Venus
"The next transit of Venus, where Venus appears as a dark spot in front of the Sun, will begin at 22:09 UTC on 5 June 2012, and will finish at 04:49 UTC on 6 June.[1] Depending on the position of the observer, the exact times can vary by up to ±7 minutes. Transits of Venus occur in pairs that are eight years apart: the previous transit was in June 2004, and the next pair of transits will occur in December 2117 and December 2125." from Wikipedia
Aristarchus proposed to measure the distance to the Sun using parallax. This approach based on the geometric principles of parallax last for two thousands of years, until Edmond Halley in 1716 proposed to observe the transit of Venus. The use of Venus transits gave an estimate of 1.53×10^13 cm, 2.6% above the currently accepted value, that of l.49 × 10^13 cm. More recently, in 1910, the parallax was measured using the asteroid Eros that passed much closer to Earth than Venus. A transit of Venus happens when this planet passes directly between the Sun and Earth, appearing as a small black disk moving across the Sun bright disk. The duration of such transits is usually measured in hours.
Read more "Two amateur astronomers at Berkeley", at http://arxiv.org/abs/1202.0950
Aristarchus proposed to measure the distance to the Sun using parallax. This approach based on the geometric principles of parallax last for two thousands of years, until Edmond Halley in 1716 proposed to observe the transit of Venus. The use of Venus transits gave an estimate of 1.53×10^13 cm, 2.6% above the currently accepted value, that of l.49 × 10^13 cm. More recently, in 1910, the parallax was measured using the asteroid Eros that passed much closer to Earth than Venus. A transit of Venus happens when this planet passes directly between the Sun and Earth, appearing as a small black disk moving across the Sun bright disk. The duration of such transits is usually measured in hours.
Read more "Two amateur astronomers at Berkeley", at http://arxiv.org/abs/1202.0950
Tuesday, May 8, 2012
An ancient rangefinder (Roman Dodecahedron)
According to Wikipedia, "a rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure (such as sonar, laser, or radar); others measure distance using trigonometry (stadiametric rangefinders and parallax, or coincidence rangefinders). These methodologies use a set of known information, usually distances or target sizes, to make the measurement, and have been in regular use since the 18th century".
It could be surprising, but probably the Roman Army had a rangefinder. It was the Roman Dodecahedron (I have already discussed it in some posts and papers: on arXiv, where I am explaining how it can be used for measuring distance as a rangefinder, http://arxiv.org/abs/1204.6497 ).
For me, those dodecahedrons having a structure with holes of different sizes, are military instruments to evaluate distances for ballistics. It is simple to use. Of course, later, during the Middle Age, different instruments had been developed for surveying: the dodecahedron was of the Roman Army, and, probably, its use lost after the collpase of the Empire. See also "Ancient and Modern Rangefinders", on arXiv, http://arxiv.org/abs/1205.2078 and on SCIRP http://www.scirp.org/journal/PaperInformation.aspx?PaperID=23245
It could be surprising, but probably the Roman Army had a rangefinder. It was the Roman Dodecahedron (I have already discussed it in some posts and papers: on arXiv, where I am explaining how it can be used for measuring distance as a rangefinder, http://arxiv.org/abs/1204.6497 ).
For me, those dodecahedrons having a structure with holes of different sizes, are military instruments to evaluate distances for ballistics. It is simple to use. Of course, later, during the Middle Age, different instruments had been developed for surveying: the dodecahedron was of the Roman Army, and, probably, its use lost after the collpase of the Empire. See also "Ancient and Modern Rangefinders", on arXiv, http://arxiv.org/abs/1205.2078 and on SCIRP http://www.scirp.org/journal/PaperInformation.aspx?PaperID=23245
Sunday, May 6, 2012
M R James - Casting the Runes
Montague Rhodes James, who used the publication name M. R. James, was an English mediaeval scholar and provost of King's College, Cambridge (1905–1918), and of Eton College (1918–1936). He is best remembered for his ghost stories. In his stories, James's protagonists and plots tend to reflect his own antiquarian interests. Among the "antiquarian ghost stories", there is the "Casting the Runes"
"One chapter in particular struck me, in which he (Karswell) spoke of "casting the Runes" on people, either for the purpose of gaining their affection or of getting them out of the way--perhaps more especially the latter: he spoke of all this in a way that really seemed to me to imply actual knowledge. ...
By way of answer, Dunning had the episode in the Manuscript Room at the British Museum to relate. 'Then he did actually hand you some papers; have you examined them? No? because we must, if you'll allow it, look at them at once, and very carefully.'
They went to the still empty house--empty, for the two servants were not yet able to return to work. Dunning's portfolio of papers was gathering dust on the writing-table. In it were the quires of small-sized scribbling paper which he used for his transcripts: and from one of these, as he took it up, there slipped and fluttered out into the room with uncanny quickness, a strip of thin light paper. The window was open, but Harrington slammed it to, just in time to intercept the paper, which he caught. 'I thought so,' he said; 'it might be the identical thing that was given to my brother. You'll have to look out, Dunning; this may mean something quite serious for you.'
A long consultation took place. The paper was narrowly examined. As Harrington had said, the characters on it were more like Runes than anything else, but not decipherable by either man, and both hesitated to copy them, for fear, as they confessed, of perpetuating whatever evil purpose they might conceal. So it has remained impossible to ascertain what was conveyed in this curious message or commission. Both Dunning and Harrington are firmly convinced that it had the effect of bringing its possessors into very undesirable company. That it must be returned to the source whence it came they were agreed, and further, that the only safe and certain way was that of personal service; and here contrivance would be necessary, for Dunning was known by sight to Karswell. ...".
http://www.classicreader.com/book/1833/1/
"One chapter in particular struck me, in which he (Karswell) spoke of "casting the Runes" on people, either for the purpose of gaining their affection or of getting them out of the way--perhaps more especially the latter: he spoke of all this in a way that really seemed to me to imply actual knowledge. ...
By way of answer, Dunning had the episode in the Manuscript Room at the British Museum to relate. 'Then he did actually hand you some papers; have you examined them? No? because we must, if you'll allow it, look at them at once, and very carefully.'
They went to the still empty house--empty, for the two servants were not yet able to return to work. Dunning's portfolio of papers was gathering dust on the writing-table. In it were the quires of small-sized scribbling paper which he used for his transcripts: and from one of these, as he took it up, there slipped and fluttered out into the room with uncanny quickness, a strip of thin light paper. The window was open, but Harrington slammed it to, just in time to intercept the paper, which he caught. 'I thought so,' he said; 'it might be the identical thing that was given to my brother. You'll have to look out, Dunning; this may mean something quite serious for you.'
A long consultation took place. The paper was narrowly examined. As Harrington had said, the characters on it were more like Runes than anything else, but not decipherable by either man, and both hesitated to copy them, for fear, as they confessed, of perpetuating whatever evil purpose they might conceal. So it has remained impossible to ascertain what was conveyed in this curious message or commission. Both Dunning and Harrington are firmly convinced that it had the effect of bringing its possessors into very undesirable company. That it must be returned to the source whence it came they were agreed, and further, that the only safe and certain way was that of personal service; and here contrivance would be necessary, for Dunning was known by sight to Karswell. ...".
http://www.classicreader.com/book/1833/1/
Casting the dice
"Cleromancy is a form of divination using sortition, casting of lots, or casting bones or stones, in which an outcome is determined by means that normally would be considered random, such as the rolling of dice, but are sometimes believed to reveal the will of God, or other supernatural entities." Source: Wikipedia
"Alea iacta est (Latin: "The die has been cast") is a Latin phrase attributed by Suetonius (as iacta alea est) to Julius Caesar on January 10, 49 BC as he led his army across the River Rubicon in Northern Italy. With this step, he entered Italy at the head of his army in defiance and began his long civil war against Pompey and the Optimates. The phrase is still used today to mean that events have passed a point of no return, that something inevitably will happen." Source: Wikipedia
"Alea iacta est (Latin: "The die has been cast") is a Latin phrase attributed by Suetonius (as iacta alea est) to Julius Caesar on January 10, 49 BC as he led his army across the River Rubicon in Northern Italy. With this step, he entered Italy at the head of his army in defiance and began his long civil war against Pompey and the Optimates. The phrase is still used today to mean that events have passed a point of no return, that something inevitably will happen." Source: Wikipedia