Mankind always has, and always will, fight wars. And in order to fight said wars, man needed weapons. Using whatever skills and resources they had, man built tools that would slash, smash, pierce and tear their enemies. Every nation had weapons that made their armies unique. Today when we talk about ancient weapons we immediately think swords, spears, bows and axes. But I find interest in weapons that strike me as out of the norm. This list is an assortment of weapons that have designs, backgrounds or usages that I find rather out of the ordinary. If you feel like anything is excluded or missing from the list, remember there exists a comment section for you to do with as you will!

# 10 Mere Club

Used by the Māori tribes of New Zealand, this simple-looking, yet solid, club was built from nephrite jade. Strangely enough, the Māori used the 12-20 inch club for jabbing and thrusting instead of swinging downward blows in the way that most other clubs are used. To the Māori, the mere was a very spiritual weapon. They named their mere clubs and passed them down through generations. They even believed that the clubs contained a mana (spiritual force) of their own. The Māori revered their mere clubs greatly. They were a symbol of leadership, and if any mere that was considered important by a tribe was misplaced, great efforts were taken by the tribe to make sure the mere was located and returned to its respective owner.

# 9 Hook Swords

Perhaps the most well-known on this list, the Chinese hook swords were wielded by the normally passive Shoalin monks of northern China. Beautifully and artistically designed, the blades were curved into a hook shape at the end which allowed the user to connect the blades by the tip and wield them as a single, long-ranged weapon. The crescent shaped guards were excellent at blocking blows as well as slashing enemies who got too close. The ends of the hilts were sharpened into daggers for stabbing at close range. These swords measured from 4-6 feet from the top of the hook to the end of the sharpened hilt. The blades saw most of their usage from civilians, as the Chinese military did not use them in any of their armies.

# 8 Kpinga

The kpinga was a throwing knife that was used by experienced warriors of the Azande tribe. The Zande people were residents of Nubia, a region in Africa composed of northern Sudan and southern Egypt. The knife (also known by its nickname, the Hunga Munga) was up to 22 inches long and had three blades that extended from the center. The blade closest to the handle is in the shape of a man’s genitals, and represented the masculine power of its owner. The alignment of the blades on the kpinga drastically increased the chances of impaling a target on contact. When the owner of the weapon was married, he presented the kpinga as a gift to the family of his wife.

# 7 Macuahuitl

The macuahuitl was basically a large, sword-shaped piece of wood, with razor-sharp pieces of obsidian embedded in the sides. Since the macuahuitl lacked a sharp point, it couldn’t be used as a stabbing weapon; however the jagged rows of obsidian gave the weapon a vicious tearing power that could cut deep lacerations in the enemy. The wood itself is heavy and strong enough to clobber opponents, thus enabling the Aztec to capture the foe alive to be used in their famous ritual sacrifices. There have been accounts of maquahuitls being able to decapitate horses, which is impressive, for a horse’s head is a good deal thicker than that of an adult human being.

# 6 Scissor

This rather odd-looking weapon was used in the arenas by the gladiators of the ancient Roman Empire. Interestingly enough, the gladiators who wielded the scissor in combat were also known as scissors. The metal casing at the bottom formed a long tube that covered the gladiator’s arm, allowing the weapon to easily block and parry, as well as counterattack. Made from hardened steel, the scissor measured up to one and a half feet long. It is surprisingly light, weighing in at an easy 5-7 pounds; this allowed the scissor to be wielded with a good amount of speed. The scissor’s unique shape and design made it a crowd favorite.

# 5 Chakram

Don’t be fooled, the chakram is not something you would want to play frisbee with. Unlike the frisbee, the chakram was often thrown vertically rather than horizontally. The deadly circle of metal was up to a foot in diameter. It’s extremely sharp edge ensured that the chakram could slice off arms and legs with ease. This weapon originated from India, where it was used extensively by the high ranking Indian Sikhs. Much like a distant relative, the shrunken, the chakram could be stacked one on the other and thrown repeatedly. One interesting throwing method used by professional warriors was to spin the chakram on their index finger, and then, with a sharp flick of the wrist, launch the whirring blade at their opponent.

# 4 Chu Ko Nu

Another Chinese weapon, the chu ko nu was basically an ancestor to the automatic rifle – it sacrificed range and power for a quick reload time. The wooden case on the top of the crossbow held 10 crossbow bolts which fell into place when the rectangular lever on the back was pulled back after firing a bolt. One interesting fact is that the chu ko nu last saw its use in the Sino-Japanese wars of 1894-1895, years after the rise of firearms. The crossbow could fire on average a total of 10 bolts within 15 seconds. Which, when compared to the reload speed of normal bows and crossbows, is a great improvement. For added effectiveness, some of the bolts were tipped with poison from the deadly aconite flower, also known as wolfsbane.

# 3 Nest of Bees

Now I have to hand it to the Chinese, their weapons have made four entries on my list. Third place is taken by the nest of bees, or flying fire. Basically it was a wooden container filled with tubes in the shape of a hexagon, which, when viewed from the front, gave the weapon the appearance of a large honeycomb. Inside each of the tubes was a rocket propelled arrow. The rockets launched the arrows with more power and range than that of a traditional bow. Up to 32 arrows could be launched from a nest at once. The Chinese would fire thousands of bees’ nests at once, killing plenty of enemies within seconds.

# 2 Katar

This Indian weapon gave its owner the claws of wolverine, minus the strength and cutting power of adamantium. The katar at first glance has a single blade, however when a trigger on the h-shaped handle was activated, the blade would split into three, one on the middle and one on each side. The three blades not only made the weapon more effective at stabbing and slashing, but they also intimidated and/or startled the opponent. The blade’s positioning on the handle also allowed it to easily block attacks. Its unusual design has yet another purpose – the triple blades could easily stab through all kinds of Asian armor with ease.

# 1 Zhua

One look at this incredibly odd-looking device was more than enough to convince me that it deserved the number one place on this list. Yet another Chinese weapon, the zhua’s conspicuous iron “hand” at the end had sharp claw-like nails that would impale flesh, and then tear it off from the body. The sheer weight of the zhua was enough to kill the opponent, but the claws made it even deadlier. When wielded by a professional, it could be used to pull mounted soldiers off their horse. But the main use of the zhua was to pull off the shields of enemies, leaving them exposed to the clawed hand of iron.

Courtesy : ISRO

Fossils are often stored in plaster casts, or jackets, to protect them from damage. Getting information about a fossil typically requires the removal of the plaster and all the sediment surrounding it, which can lead to loss of material or even destruction of the fossil itself.German researchers studied the feasibility of using CT and 3-D printers to nondestructively separate fossilized bone from its surrounding sediment matrix and produce a 3-D print of the fossilized bone itself.

\"The most important benefit of this method is that it is non-destructive, and the risk of harming the fossil is minimal," said study author Ahi Sema Issever, M.D., from the Department of Radiology at Charité Campus Mitte in Berlin. "Also, it is not as time-consuming as conventional preparation."

Dr. Issever and colleagues applied the method to an unidentified fossil from the Museum für Naturkunde, a major natural history museum in Berlin. The fossil and others like it were buried under rubble in the basement of the museum after a World War II bombing raid. Since then, museum staff members have had difficulty sorting and identifying some of the plaster jackets.Researchers performed CT on the unidentified fossil with a 320-slice multi-detector system. The different attenuation, or absorption of radiation, through the bone compared with the surrounding matrix enabled clear depiction of a fossilized vertebral body.

After studying the CT scan and comparing it to old excavation drawings, the researchers were able to trace the fossil's origin to the Halberstadt excavation, a major dig from 1910 to 1927 in a clay pit south of Halberstadt, Germany. In addition, the CT study provided valuable information about the condition and integrity of the fossil, showing multiple fractures and destruction of the front rim of the vertebral body.Furthermore, the CT dataset helped the researchers build an accurate reconstruction of the fossil with selective laser sintering, a technology that uses a high-powered laser to fuse together materials to make a 3-D object.

Dr. Issever noted that the findings come at a time when advances in technology and cheaper availability of 3-D printers are making them more common as a tool for research. Digital models of the objects can be transferred rapidly among researchers, and endless numbers of exact copies may be produced and distributed, greatly advancing scientific exchange, Dr. Issever said. The technology also potentially enables a global interchange of unique fossils with museums, schools and other settings.

"The digital dataset and, ultimately, reproductions of the 3-D print may easily be shared, and other research facilities could thus gain valuable informational access to rare fossils, which otherwise would have been restricted," Dr. Issever said. "Just like Gutenberg's printing press opened the world of books to the public, digital datasets and 3-D prints of fossils may now be distributed more broadly, while protecting the original intact fossil."

ndia launched its first mission to Mars this afternoon from the Sriharikota spaceport in Andhra Pradesh, beginning a 300-day journey to study the Martian atmosphere.

Mangalyaan, which means "Mars craft" in Hindi, is the size of a small car and is scheduled to begin orbiting Mars by September, searching for methane and signs of minerals.

The satellite is golden in colour and is being carried by a rocket much smaller than American or Russian equivalents.

Lacking the power to fly directly, the 350-tonne launch vehicle will orbit Earth for nearly a month, building up the necessary velocity to break free from our planet's gravitational pull.

Only then will it begin the second stage of its nine-month journey which will test India's scientists to the full, five years after they sent a probe called Chandrayaan to the moon.

The total cost of the project is 450 crores, one sixth of the cost of a Mars probe set to be launched by NASA in 13 days.

Only the United States, Europe, and Russia have sent probes that have orbited or landed on Mars. Probes to Mars have a high failure rate. A similar mission by China failed to leave Earth's orbit in 2011.

"This is a technology demonstration project, a mission that will announce to the world India has the capability to reach as far away as Mars, "said K. Radhakrishnan, chairman of the Indian Space and Research Organization

Source: ndtv.com

Computer Sketch At its glory...

2013 Nobel Laureates

Physiology or Medicine:
James E. Rothman, Randy W. Schekman and Thomas C. Südhof

Physics:
François Englert and Peter Higgs

Chemistry:
Martin Karplus, Michael Levitt and Arieh Warshel

Literature:
Alice Munro

Peace:
 Organization for the Prohibition of Chemical Weapons 

Economic Sciences:
Eugene F. Fama, Lars Peter Hansen, Robert J. Shiller

Sachin Tendulkar started off with centuries in his debut matches in the Ranji, Duleep and Irani Trophy. No other domestic cricketer has been able to break this record till now.

Sachin Tendulkar was done in by a sharp bouncer from Zimbabwe’s Henry Olonga in a league match at Sharjah in 1998. In the final match against the same opposition, Tendulkar had his revenge as he smashed the bowler all around the ground and belted an unbeaten 118 runs.

Sachin Tendulkar is a big fan of tennis legend John McEnroe. In his formative years, McEnroe was Tendulkar’s idol. The young Sachin pleaded his parents to get a similar headband and wristbands like McEnroe. Also take one look at his childhood snaps and the McEnroe styled shock of hair on his head tells everything.

Sachin Tendulkar was named after the great musician SD Burman. Sachin’s father’s, Ramesh Tendulkar was a big fan of SD’s music.

 Sachin Tendulkar was led onto the field on his Ranji debut by his then captain, Ravi Shastri.

Sachin Tendulkar was gifted a Ferrari 360 Modena by F1 champion Michael Schumacher in 2002. Ferrari presented the car to Sachin in honour of him equalling Don Bradman’s record of 29 Test centuries.

Sachin Tendulkar spoke to his favourite music star, Mark Knopfler, the lead guitarist of the rock band, Dire Straits for the very first time during a programme he was doing for the ESPN network. It was Sachin’s birthday and it turned out to be a happy surprise for him.

Sachin Tendulkar went to watch the movie Roja in 1995 with a beard and disguise. And it all went wrong when his glasses fell off and the crowd in the cinema hall recognised him.

 Sachin Tendulkar returned from a four-month tour of Australia after the 1992 World Cup and immediately turned up to represent Kirti College in April 1992. That’s some commitment from a cricketer who was already a superstar by then.

 Sachin Tendulkar uses a very heavy bat at the crease, weighing 3.2lbs. Only South Africa's Lance Klusener used a heavier bat in world cricket.

Sachin Tendulkar wanted to become a fast bowler, but when he was rejected by Dennis Lillee’s MRF Pace Foundation in 1987. Lillee told the young Tendulkar to focus on his batting. The other youngster turned away by Lillee along with Tendulkar was Sourav Ganguly.

Sachin Tendulkar fielded for Pakistan as a substitute during a one-day practice match against India at the Brabourne Stadium in 1988.

Sachin Tendulkar and Vinod Kambli set a world record partnership of 664 runs in the Harris Shield, an inter-school tournament in Mumbai. Tendulkar scored an unbeaten 326 runs and reportedly the mammoth stand literally drove the opposition to tears.

Sachin Tendulkar at the age of 19 became the youngest Indian to play in county cricket.

Sachin Tendulkar had to wait for 79 matches for his first ODI century and by that time he had scored seven Test hundreds.

Sachin Tendulkar was the first batsman to be given out by the Third-umpire. In 1992, on the second day of the Durban Test, a Jonty Rhodes throw caught Tendulkar short of the crease. After watching TV replays he was adjudged out.

7. Sachin Tendulkar made his Test debut in 1989 against Pakistan in Karachi. In the same match, Pakistani pacer Waqar Younis also played his first Test match ever.

Sachin Tendulkar went to Sharadashram Vidyamandir School only after coach Ramakant Achrekar saw his batting potential. Achrekar was the cricket coach of Sharadashram Vidyamandir School. Before enrolling at Shardashram, Tendulkar went to New England School of Indian Education Society in East Bandra

The first brand which Sachin Tendulkar endorsed was the health drink ‘Boost.’ He was seen alongside Kapil Dev in many of their ad films, the start of which happened in 1990.

English fast bowler Allan Mulally playing in his debut Test against India complained that Sachin Tendulkar was batting with a bat broader than the normal willow. That’s how much Tendulkar had psyched the bowler with his brilliant batting.

Sachin Tendulkar was without a bat contract until the start of the 1996 Cricket World Cup. At the end of the tournament a famous tyre manufacturer sponsored his willow.

Sachin Tendulkar was a big bully in the school. Whenever his friend introduced him to a new kid in the school, Tendulkar would invariably ask, “Will I be able to beat him?’ He was famous for picking up a fight.

Sachin Tendulkar asked his friend to dip the tennis ball in a bucket of water and hurl at him so that he could find out whether he was hitting ball from the middle of his bat.

Sachin Tendulkar has been granted the Rajiv Gandhi Khel Ratna, Arjuna Award and Padma Shri by Indian government. He is the only Indian cricketer to get all of them.

Sachin Tendulkar played for Yorkshire what was so special about it? Well, he was the county side’s first overseas professional ever. He averaged 46.52 with the bat in his stint with the county team.

Sachin Tendulkar's wife Anjali does not eat or drink whenever the Master is at the crease.

Sachin Tendulkar was most fascinated by band-aids. A hint of a wound and he would plaster it all over the injury.

Sachin Tendulkar loves collecting perfumes and watches.

Sachin Tendulkar batted in his debut Test against Pakistan wearing the pads gifted to him by Sunil Gavaskar

In 1992 Sachin became the youngest cricketer to reach a 1000 runs in Test cricket

Ashley Giles was the first bowler to get him stumped out in Test cricket in 2002

Sachin’s record of five test centuries before he turned 20 is a current world record.

Tendulkar is the only player who has 40 wkts and more than 11000 runs in Tests

Sachin Tendulkar has the most number of Stadium Appearances: 90 different Grounds

35. Sachin Tendulkar with Sourav Ganguly hold the world record for the maximum number of runs scored by the opening partnership. They have put together 6,271 runs in 128 matches.

36. He has 20 century partnerships for opening pair with Sourav Ganguly is a world record.

37. Tendulkar has scored most Centuries in a calendar year: 9 ODI centuries in 1998.

38. In 1998 he made 1,894 ODI runs, a record for ODI runs by any batsman in a calendar year.

In 2011, when an MIT senior named John Romanishin proposed a new design for modular robots to his robotics professor, Daniela Rus, she said, "That can't be done."Two years later, Rus showed her colleague Hod Lipson, a robotics researcher at Cornell University, a video of prototype robots, based on Romanishin's design, in action. "That can't be done," Lipson said.

In November, Romanishin -- now a research scientist in MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) -- Rus, and postdoc Kyle Gilpin will establish once and for all that it can be done, when they present a paper describing their new robots at the IEEE/RSJ International Conference on Intelligent Robots and Systems.

Known as M-Blocks, the robots are cubes with no external moving parts. Nonetheless, they're able to climb over and around one another, leap through the air, roll across the ground, and even move while suspended upside down from metallic surfaces.Inside each M-Block is a flywheel that can reach speeds of 20,000 revolutions per minute; when the flywheel is braked, it imparts its angular momentum to the cube. On each edge of an M-Block, and on every face, are cleverly arranged permanent magnets that allow any two cubes to attach to each other.

"It's one of these things that the [modular-robotics] community has been trying to do for a long time," says Rus, a professor of electrical engineering and computer science and director of CSAIL. "We just needed a creative insight and somebody who was passionate enough to keep coming at it -- despite being discouraged."

Embodied abstraction
As Rus explains, researchers studying reconfigurable robots have long used an abstraction called the sliding-cube model. In this model, if two cubes are face to face, one of them can slide up the side of the other and, without changing orientation, slide across its top.The sliding-cube model simplifies the development of self-assembly algorithms, but the robots that implement them tend to be much more complex devices. Rus' group, for instance, previously developed a modular robot called the Molecule, which consisted of two cubes connected by an angled bar and had 18 separate motors. "We were quite proud of it at the time," Rus says.

According to Gilpin, existing modular-robot systems are also "statically stable," meaning that "you can pause the motion at any point, and they'll stay where they are." What enabled the MIT researchers to drastically simplify their robots' design was giving up on the principle of static stability.

"There's a point in time when the cube is essentially flying through the air," Gilpin says. "And you are depending on the magnets to bring it into alignment when it lands. That's something that's totally unique to this system."
That's also what made Rus skeptical about Romanishin's initial proposal. "I asked him build a prototype," Rus says. "Then I said, 'OK, maybe I was wrong.'"

Sticking the landing

To compensate for its static instability, the researchers' robot relies on some ingenious engineering. On each edge of a cube are two cylindrical magnets, mounted like rolling pins. When two cubes approach each other, the magnets naturally rotate, so that north poles align with south, and vice versa. Any face of any cube can thus attach to any face of any other.

The cubes' edges are also beveled, so when two cubes are face to face, there's a slight gap between their magnets. When one cube begins to flip on top of another, the bevels, and thus the magnets, touch. The connection between the cubes becomes much stronger, anchoring the pivot. On each face of a cube are four more pairs of smaller magnets, arranged symmetrically, which help snap a moving cube into place when it lands on top of another.

As with any modular-robot system, the hope is that the modules can be miniaturized: the ultimate aim of most such research is hordes of swarming microbots that can self-assemble, like the "liquid steel" androids in the movie "Terminator II." And the simplicity of the cubes' design makes miniaturization promising.

But the researchers believe that a more refined version of their system could prove useful even at something like its current scale. Armies of mobile cubes could temporarily repair bridges or buildings during emergencies, or raise and reconfigure scaffolding for building projects. They could assemble into different types of furniture or heavy equipment as needed. And they could swarm into environments hostile or inaccessible to humans, diagnose problems, and reorganize themselves to provide solutions.


Strength in diversity


The researchers also imagine that among the mobile cubes could be special-purpose cubes, containing cameras, or lights, or battery packs, or other equipment, which the mobile cubes could transport. "In the vast majority of other modular systems, an individual module cannot move on its own," Gilpin says. "If you drop one of these along the way, or something goes wrong, it can rejoin the group, no problem."

"It's one of those things that you kick yourself for not thinking of," Cornell's Lipson says. "It's a low-tech solution to a problem that people have been trying to solve with extraordinarily high-tech approaches."

"What they did that was very interesting is they showed several modes of locomotion," Lipson adds. "Not just one cube flipping around, but multiple cubes working together, multiple cubes moving other cubes -- a lot of other modes of motion that really open the door to many, many applications, much beyond what people usually consider when they talk about self-assembly. They rarely think about parts dragging other parts -- this kind of cooperative group behavior."

In ongoing work, the MIT researchers are building an army of 100 cubes, each of which can move in any direction, and designing algorithms to guide them. "We want hundreds of cubes, scattered randomly across the floor, to be able to identify each other, coalesce, and autonomously transform into a chair, or a ladder, or a desk, on demand," Romanishin says.

An international research team, led by researcher at the University of Electro-Communication observed an infrared dark cloud G34.43+00.24 MM3 with ALMA and discovered a baby star surrounded by a large hot cloud. This hot cloud is about ten times larger than those found around typical solar-mass baby stars.

Hot molecular clouds around new-born stars are called "Hot Cores" and have temperature of -- 160 degrees Celsius, 100 degrees hotter than normal molecular clouds. The large size of the hot core discovered by ALMA shows that much more energy is emitted from the central baby star than typical solar-mass young stars. This may be due to the higher mass infall rate, or multiplicity of the central baby star. This result indicates a large diversity in the star formation process.

The research findings are presented in the article "ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and Molecular Outflows," published in the Astrophysical Journal, Vol. 775, of September 20, 2013.

A large hot molecular cloud around a very young star was discovered by ALMA. This hot cloud is about ten times larger than those found around typical solar-mass baby stars, which indicates that the star formation process has more diversity than ever thought. This result was published in the Astrophysical Journal on September 20th, 2013.

Stars are formed in very cold (-260 degrees Celsius) gas and dust clouds. Infrared Dark Clouds (IRDC) are dense regions of such clouds, and thought that in which clusters of stars are formed. Since most of stars are born as members of star clusters, investigating IRDCs has a crucial role in comprehensive understanding the star formation process.

A baby star is surrounded by the natal gas and dust cloud, and the cloud is warmed up from its center. Temperature of the central part of some, but not all, of such clouds reaches as high as -160 degrees Celsius. Astronomers call those clouds as "hot core" -- it may not be hot on Earth, but is hot enough for a cosmic cloud. Inside hot cores, various molecules, originally trapped in the ice mantle around dust particles, are sublimated. Organic molecules such as methanol (CH3OH), ethyl cyanide (CH3CH2CN), and methyl formate (HCOOCH3) are abundant in hot cores.

International research team, led by Takeshi Sakai at the University of Electro-Communication, Japan, used ALMA to observe an IRDC named G34.43+00.24 MM3 (hereafter MM3) in the constellation Aquila (the Eagle). They discovered a young object from which the methanol molecular line is strongly emitted. A detailed investigation tells them that the temperature of the methanol gas is -140 degrees Celsius. This shows that MM3 harbors a baby star surrounded by a hot core. The size of the hot core is as large as 800 times 300 astronomical units (au, 1 au equals to the mean distance of the Sun and Earth; 150 million km). Typical size of hot cores around low-mass young stars is several tens to hundred of au, therefore the hot core in MM3 is exceptionally large. Sakai says "Thanks to the high sensitivity and spatial resolution, we need only a few hours to discover a previously unknown baby star. This is an important step to understand the star formation process in a cluster forming region."

The team also observed radio emission from carbon sulfide (CS) and silicon monoxide (SiO) to reveal the detailed structure of the molecular outflow from the baby star. The speed of the emanated gas is 28 km/s and the extent is 4,400 au. Based on these values, the team calculates the age of the outflow of only 740 years. Although molecular outflows are common features around protostars, the outflow as young as the one in MM3 is quite rare. In summary, ALMA finds that the protostar in MM3 is very young but has a giant hot core.

Why the hot core in MM3 is so large? In order to warm up the large volume of gas, the baby star should emit much more energy than typical ones. Protostars produce emission by converting the gravitational energy of infalling material to the thermal energy. The large size of the hot core in MM3 is possibly due to the high mass infalling rate than ever thought. The other possibility is that two or more protostars are embedded in the hot core. The research team has not reached the reason with this observation yet. "ALMA's spatial resolution improves much more in the near future," Sakai says, "Then much detail of the infalling material toward the protostar can be revealed, and it helps us answer to the mystery behind the diversity in star formation."

In a completely unexpected finding, MIT researchers have discovered that tiny water droplets that form on a superhydrophobic surface, and then "jump" away from that surface, carry an electric charge. The finding could lead to more efficient power plants and a new way of drawing power from the atmosphere, they say.

The finding is reported in a paper in the journal Nature Communications written by MIT postdoc Nenad Miljkovic, mechanical engineering professor Evelyn Wang, and two others.

Miljkovic says this was an extension of previous work by the MIT team. That work showed that under certain conditions, rather than simply sliding down and separating from a surface due to gravity, droplets can actually leap away from it. This occurs when droplets of water condense onto a metal surface with a specific kind of superhydrophobic coating and at least two of the droplets coalesce: They can then spontaneously jump from the surface, as a result of a release of excess surface energy.

In the new work, "We found that when these droplets jump, through analysis of high-speed video, we saw that they repel one another midflight," Miljkovic says. "Previous studies have shown no such effect. When we first saw that, we were intrigued."

In order to understand the reason for the repulsion between jumping droplets after they leave the surface, the researchers performed a series of experiments using a charged electrode. Sure enough, when the electrode had a positive charge, droplets were repelled by it as well as by each other; when it had a negative charge, the droplets were drawn toward it. This established that the effect was caused by a net positive electrical charge forming on the droplets as they jumped away from the surface.

The charging process takes place because as droplets form on a surface, Miljkovic says, they naturally form an electric double layer -- a layer of paired positive and negative charges -- on their surfaces. When neighboring drops coalesce, which leads to their jumping from the surface, that process happens "so fast that the charge separates," he says. "It leaves a bit of charge on the droplet, and the rest on the surface."

The initial finding that droplets could jump from a condenser surface -- a component at the heart of most of the world's electricity-generating power plants -- provided a mechanism for enhancing the efficiency of heat transfer on those condensers, and thus improving power plants' overall efficiency. The new finding now provides a way of enhancing that efficiency even more: By applying the appropriate charge to a nearby metal plate, jumping droplets can be pulled away from the surface, reducing the likelihood of their being pushed back onto the condenser either by gravity or by the drag created by the flow of the surrounding vapor toward the surface, Miljkovic says

."Now we can use an external electric field to mitigate" any tendency of the droplets to return to the condenser, "and enhance the heat transfer," he says.

But the finding also suggests another possible new application, Miljkovic says: By placing two parallel metal plates out in the open, with "one surface that has droplets jumping, and another that collects them … you could generate some power" just from condensation from the ambient air. All that would be needed is a way of keeping the condenser surface cool, such as water from a nearby lake or river. "You just need a cold surface in a moist environment," he says. "We're working on demonstrating this concept."

The research team also included graduate student Daniel Preston and Ryan Enright, who was a postdoc at MIT and the University of Limerick and is now at Bell Labs Ireland, part of Alcatel-Lucent. The work received funding from the U.S. Department of Energy through the MIT Solid-State Solar-Thermal Energy Conversion Center, the Office of Naval Research and the National Science Foundation.

The "pane" of glass, so impossibly thin that its individual silicon and oxygen atoms are clearly visible via electron microscopy, was identified in the lab of David A. Muller, professor of applied and engineering physics and director of the Kavli Institute at Cornell for Nanoscale Science.

The work that describes direct imaging of this thin glass was first published in January 2012 in Nano Letters, and the Guinness records officials took note. The record will now be published in the Guinness World Records 2014 Edition.

Just two atoms in thickness, the glass was an accidental discovery, Muller said. The scientists had been making graphene, a two-dimensional sheet of carbon atoms in a chicken wire crystal formation, on copper foils in a quartz furnace. They noticed some "muck" on the graphene, and upon further inspection, found it to be composed of the elements of everyday glass, silicon and oxygen.

They concluded that an air leak had caused the copper to react with the quartz, also made of silicon and oxygen. This produced the glass layer on the would-be pure graphene.Besides its sheer novelty, Muller said, the work answers an 80-year-old question about the fundamental structure of glass. Scientists, with no way to directly see it, had struggled to understand it: it behaves like a solid, but was thought to look more like a liquid. Now, the Cornell scientists have produced a picture of individual atoms of glass, and they found that it strikingly resembles a diagram drawn in 1932 by W.H. Zachariasen -- a longstanding theoretical representation of the arrangement of atoms in glass.

"This is the work that, when I look back at my career, I will be most proud of," Muller said. "It's the first time that anyone has been able to see the arrangement of atoms in a glass."

What's more, two-dimensional glass could someday find a use in transistors, by providing a defect-free, ultra-thin material that could improve the performance of processors in computers and smartphones.

Scientists at the Universities of Oxford, St Andrews, Bristol and the Max Plank Institute in Nijmegen, the Netherlands, found correlations between handedness and a network of genes involved in establishing left-right asymmetry in developing embryos.

'The genes are involved in the biological process through which an early embryo moves on from being a round ball of cells and becomes a growing organism with an established left and right side,' explained first author William Brandler, a PhD student in the MRC Functional Genomics Unit at Oxford University.

The researchers suggest that the genes may also help establish left-right differences in the brain, which in turn influences handedness.

They report their findings in the open-access journal PLOS Genetics.

Humans are the only species to show such a strong bias in handedness, with around 90% of people being right-handed. The cause of this bias remains largely a mystery.

The researchers, led by Dr Silvia Paracchini at the University of St Andrews, were interested in understanding which genes might have an influence on handedness, in order to gain an insight into the causes and evolution of handedness.

The team carried out a genome-wide association study to identify any common gene variants that might correlate with which hand people prefer using.

The most strongly associated, statistically significant variant with handedness is located in the gene PCSK6, which is involved in the early establishment of left and right in the growing embryo.

The researchers then made full use of knowledge from previous studies of what PCSK6 and similar genes do in mice to reveal more about the biological processes involved.

Disrupting PCSK6 in mice causes 'left-right asymmetry' defects, such as abnormal positioning of organs in the body. They might have a heart and stomach on the right and their liver on the left, for example.

The researchers found that variants in other genes known to cause left-right defects when disrupted in mice were more likely to be associated with relative hand skill than you would expect by chance.

While the team has identified a role for genes involved in establishing left from right in embryo development, William Brandler cautioned that these results do not completely explain the variation in handedness seen among humans. He said: 'As with all aspects of human behaviour, nature and nurture go hand-in-hand. The development of handedness derives from a mixture of genes, environment, and cultural pressure to conform to right-handedness.'

Super-Earths are emerging as a new type of exoplanet (i.e., a planet orbiting a star outside of our Solar System) with a mass and radius larger than Earth's but less than those of ice giants in our Solar System, such as Uranus or Neptune. Whether super-Earths are more like a "large Earth" or a "small Uranus" is unknown, since scientists have yet to determine their detailed properties. The current Japanese research team of astronomers and planetary scientists focused their efforts on investigating the atmospheric features of one super-Earth, GJ 1214 b, which is located 40 light years from Earth in the constellation Ophiuchus, northwest of the center of our Milky Way galaxy. This planet is one of the well-known super-Earths discovered by Charbonneau et. al. (2009) in the MEarth Project, which focuses on finding habitable planets around nearby small stars. The current team's research examined features of light scattering of GJ 1214 b's transit around its star.

Current theory posits that a planet develops in a disk of dense gas surrounding a newly formed star (i.e., a protoplanetary disk). The element hydrogen is a major component of a protoplanetary disk, and water ice is abundant in an outer region beyond a so-called "snow line." Findings about where super-Earths have formed and how they have migrated to their current orbits point to the prediction that hydrogen or water vapor is a major atmospheric component of a super-Earth. If scientists can determine the major atmospheric component of a super-Earth, they can then infer the planet's birthplace and formation history.

Planetary transits enable scientists to investigate changes in the wavelength in the brightness of the star (i.e., transit depth), which indicate the planet's atmospheric composition. Strong Rayleigh scattering in the optical wavelength is powerful evidence for a hydrogen-dominated atmosphere. Rayleigh scattering occurs when light particles scatter in a medium without a change in wavelength. Such scattering strongly depends on wavelength and enhances short wavelengths; it causes greater transit depth in the blue rather than in the red wavelength.

The current team used the two optical cameras Suprime-Cam and FOCAS on the Subaru Telescope fitted with a blue transmission filter to search for the Rayleigh scattering feature of GJ 1214 b's atmosphere. This planetary system's very faint host star in blue light poses a challenge for researchers seeking to determine whether or not the planet's atmosphere has strong Rayleigh scattering. The large, powerful light-collecting 8.2 m mirror of the Subaru Telescope allowed the team to achieve the highest-ever sensitivity in the bluest region.

The team's observations showed that GJ 1214 b's atmosphere does not display strong Rayleigh scattering. This finding implies that the planet has a water-rich or a hydrogen-dominated atmosphere with extensive clouds.

Although the team did not completely discount the possibility of a hydrogen-dominated atmosphere, the new observational result combined with findings from previous research in other colors suggests that GJ 1214 b is likely to have a water-rich atmosphere. The team plans to conduct follow-up observations in the near future to reinforce their conclusion.

Although there are only a small number of super-Earths that scientists can observe in the sky now, this situation will dramatically change when the Transiting Exoplanet Survey Satellite (TESS) begins its whole sky survey of small transiting exoplanets in our solar neighborhood. When new targets become available, scientists can study the atmospheres of many super-Earths with the Subaru Telescope and next generation, large telescopes such as the Thirty Meter Telescope (TMT). Such observations will allow scientists to learn even more about the nature of various super-Earths.

The scientists investigated the genomic basis for echolocation, one of the most well-known examples of convergent evolution to examine the frequency of the process at a genomic level.


Echolocation is a complex physical trait that involves the production, reception and auditory processing of ultrasonic pulses for detecting unseen obstacles or tracking down prey, and has evolved separately in different groups of bats and cetaceans (including dolphins).The scientists carried out one of the largest genome-wide surveys of its type to discover the extent to which convergent evolution of a physical feature involves the same genes.

They compared genomic sequences of 22 mammals, including the genomes of bats and dolphins, which independently evolved echolocation, and found genetic signatures consistent with convergence in nearly 200 different genomic regions concentrated in several 'hearing genes'.To perform the analysis, the team had to sift through millions of letters of genetic code using a computer program developed to calculate the probability of convergent changes occurring by chance, so they could reliably identify 'odd-man-out' genes.

They used a supercomputer at Queen Mary's School of Physics and Astronomy (GridPP High Throughput Cluster) to carry out the survey.Consistent with an involvement in echolocation, signs of convergence among bats and the bottlenose dolphin were seen in many genes previously implicated in hearing or deafness.

"We had expected to find identical changes in maybe a dozen or so genes but to see nearly 200 is incredible," explains Dr Joe Parker, from Queen Mary's School of Biological and Chemical Sciences and first author on the paper."We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing."

Dr. Georgia Tsagkogeorga, who undertook the assembly of the new genome data for this study, added: "We found that molecular signals of convergence were widespread, and were seen in many genes across the genome. It greatly adds to our understanding of genome evolution."Group leader, Dr Stephen Rossiter, said: "These results could be the tip of the iceberg. As the genomes of more species are sequenced and studied, we may well see other striking cases of convergent adaptations being driven by identical genetic changes."

1918 October - Arab troops led by Emir Feisal, and supported by British forces, capture Damascus, ending 400 years of Ottoman rule.

The Ottoman governor of Syria, Jamal Pasha, rides through Damascus in 1917

1919 - Emir Feisal backs Arab self-rule at the Versailles peace conference, following the defeat of Germany and the Ottoman Empire in World War I.

1919 June - Elections for a Syrian National Congress are held. The new assembly includes delegates from Palestine.

1920 March - The National Congress proclaims Emir Feisal king of Syria "in its natural boundaries" from the Taurus mountains in Turkey to the Sinai desert in Egypt.

French control

1920 June - San Remo conference splits up Feisal's newly-created Arab kingdom by placing Syria-Lebanon under a French mandate, and Palestine under British control.

1920 July - French forces occupy Damascus, forcing Feisal to flee abroad.

Aleppo, along with Damascus, is one of the oldest continuously inhabited cities

1920 August - France proclaims a new state of Greater Lebanon.

1922 - Syria is divided into three autonomous regions by the French, with separate areas for the Alawis on the coast and the Druze in the south.

Uprising

1925-6 - Nationalist agitation against French rule develops into a national uprising. French forces bombard Damascus.

1928 - Elections held for a constituent assembly, which drafts a constitution for Syria. French High Commissioner rejects the proposals, sparking nationalist protests.

1936 - France agrees to Syrian independence in principle but signs an agreement maintaining French military and economic dominance.

1940 - World War II: Syria comes under the control of the Axis powers after France falls to German forces.

1941 - British and Free French troops occupy Syria. General De Gaulle promises to end the French mandate.

1945 - Protests over the slow pace of French withdrawal.

1946 - Last French troops leave Syria.

Baath Party founded

1947 - Michel Aflaq and Salah-al-Din al-Bitar found the Arab Socialist Baath Party.

1949 - Army officer Adib al-Shishakhli seizes power in the third military coup in the space of a year.

1952 - Al-Shishakli dissolves all political parties.

1954 - Army officers lead a coup against Al-Shishakli, but return a civilian government to power.

1955 - Veteran nationalist Shukri al-Quwatli is elected president. Syria seeks closer ties with Egypt.

United Arab Republic

1958 February - Syria and Egypt join the United Arab Republic (UAR). Egyptian president Gamal Abdel Nasser heads the new state. He orders the dissolution of Syrian political parties, to the dismay of the Baath party, which had campaigned for union.

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Israel occupied the Golan Heights in 1967 during the Six Day War

• Golan Heights profile

1961 September - Discontent with Egyptian domination of the UAR prompts a group of Syrian army officers to seize power in Damascus and dissolve the union.

1963 March - Army officers seize power. A Baathist cabinet is appointed and Amin al-Hafez becomes president.

Rise of Assad

1966 February - Salah Jadid leads an internal coup against the civilian Baath leadership, overthrowing Amin al-Hafez and arresting Salah al-Din al-Bitar and Michel Aflaq. Hafez al-Assad becomes defence minister.

1967 June - Israeli forces seize the Golan Heights from Syria and destroy much of Syria's air force in the Six Day War with Egypt, Jordan and Syria.

1970 November - Hafez al-Assad overthrows president Nur al-Din al-Atasi and imprisons Salah Jadid.

1971 March - Assad is elected president for a seven-year term in a plebiscite.

1973 - Rioting breaks out after Assad drops the constitutional requirement that the president must be a Muslim. He is accused of heading an atheist regime. The riots are suppressed by the army.

War with Israel

1973 October - Syria and Egypt go to war with Israel but fail to retake the Golan Heights seized during the 1967 Arab-Israeli war.

1974 May - Syria and Israel sign a disengagement agreement.

1975 February - Assad says he's prepared to make peace with Israel in return for an Israeli withdrawal from "all occupied Arab land".

1976 June - Syrian army intervenes in the Lebanese civil war to ensure that the status quo is maintained, and the Maronites remain in power.

1978 - In response to the Camp David peace agreement between Egypt and Israel, Assad sets out to gain strategic parity with Israel.

Riots

1980 - After the Islamic Revolution in Iran, Muslim groups instigate uprisings and riots in Aleppo, Homs and Hama. Assad begins to stress Syria's adherence to Islam. Syria profile

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Hafez al-Assad brought stability, but did so through repression

• Obituary: Syria's shrewd master

Syria profile

1980 - Muslim Brotherhood member tries to assassinate Assad.

1980 September - Start of Iran-Iraq war. Syria backs Iran, in keeping with the traditional rivalry between Baathist leaderships in Iraq and Syria.

1981 December - Israel annexes the Golan Heights.

Uprising in Hama

1982 February - Muslim Brotherhood uprising in the city of Hama. The revolt is suppressed by the military, whom rights organisations accuse of killing tens of thousands of civilians.

1982 June - Israel invades Lebanon and attacks the Syrian army, forcing it to withdraw from several areas. Israel attacks the PLO base in Beirut.

1983 May - Lebanon and Israel announce the end of hostilities. Syrian forces remain in Lebanon.

1983 - Assad suffers a heart attack, according to reports denied by authorities. Assad's brother Rifaat apparently prepares to take power.

1984 Rifaat is promoted to the post of vice-president.

Return to Lebanon

1987 February - Assad sends troops into Lebanon for a second time to enforce a ceasefire in Beirut.

1990 - Iraq invades Kuwait; Syria joins the US-led coalition against Iraq. This leads to improved relations with Egypt and the US.

1991 October - Syria participates in the Middle East peace conference in Madrid and holds talks with Israel that founder over the Golan Heights issue.

1994 - Assad's son Basil, who was likely to succeed his father, is killed in a car accident.

Rifaat sacked

1998 - Assad's brother Rifaat is "relieved of his post" as vice-president.

Damascus urban sprawl

1999 December - Talks with Israel over the Golan Heights begin in the US, but are indefinitely postponed the following month.

Assad succession

2000 June - Assad dies and is succeeded by his second son, Bashar.

2000 November - The new President Assad orders the release of 600 political prisoners.

2001 April - Outlawed Muslim Brotherhood says it will resume political activity, 20 years after its leaders were forced to flee.

2001 5 May - Pope John Paul II pays historic visit.

2001 June - Syrian troops evacuate Beirut, redeploy in other parts of Lebanon, following pressure from Lebanese critics of Syria's presence.

2001 September - Detention of MPs and other pro-reform activists, crushing hopes of a break with the authoritarian past of Hafez al-Assad. Arrest continue, punctuated by occaisional amnesties, over the following decade.

2001 November - British PM Tony Blair visits to try shore up support for the campaign against terror. He and President Assad fail to agree on a definition of terrorism.

Tensions with US

2002 May - Senior US official includes Syria in a list of states that make-up an "axis of evil", first listed by President Bush in January. Undersecretary for State John Bolton says Damascus is acquiring weapons of mass destruction.

2003 April - US threatens sanctions if Damascus fails to take what Washington calls the "right decisions". Syria denies US allegations that it is developing chemical weapons and helping fugitive Iraqis.

2003 September - President Assad appoints Mohammed Naji al-Otari prime minister.

2003 October - Israeli air strike against Palestinian militant camp near Damascus. Syria says action is "military aggression".

2004 January - President Assad visits Turkey, the first Syrian leader to do so. The trip marks the end of decades of frosty relations, although ties sour again after the popular uprising in 2011.

2004 March - At least 25 killed in clashes between members of the Kurdish minority, police and Arabs in the north-east.

2004 May - US imposes economic sanctions on Syria over what it calls its support for terrorism and failure to stop militants entering Iraq.

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Syria and Lebanon

The killing of former Lebanese PM Rafik Hariri sparked anti-Syrian protets in Beirut

• Syria withdrawal: Lebanese speak
• Q&A: Syria and Lebanon

2004 September - UN Security Council resolution calls for all foreign forces to leave Lebanon.

Pressure over Lebanon

2005 February-April- Tensions with the US escalate after the killing of former Lebanese PM Hariri in Beirut. Washington cites Syrian influence in Lebanon. Damascus is urged to withdraw its forces from Lebanon, which it does by April.

2005 October - Interior minister and Syria's former head of intelligence in Lebanon, Ghazi Kanaan, dies in what officials say is suicide. UN inquiry into assassination of former Lebanese PM Rafik Hariri implicates senior Syrian officials.

2005 December - Exiled former vice-president Abdul Halim Khaddam alleges that Syrian leaders threatened former Lebanese PM Hariri before his assassination.

2006 February - Danish and Norwegian embassies in Damascus are set on fire during a demonstration against cartoons in a Danish newspaper portraying the Muslim Prophet Muhammad.

2006 September - Attack on the US embassy in Damascus. Four gunmen open fire and throw grenades but fail to detonate a car bomb. Three of them are killed, one is captured.

Diplomatic overtures

2006 November - Iraq and Syria restore diplomatic relations after nearly a quarter century.

2007 March - European Union relaunches dialogue with Syria.

2007 April - US House of Representatives Speaker Nancy Pelosi meets President Assad in Damascus. She is the highest-placed US politician to visit Syria in recent years. Secretary of State Condoleezza Rice meets Foreign Minister Walid Muallem the following month in the first contact at this level for two years.

2007 May - Leading dissident Kamal Labwani and prominent political writer Michel Kilo are sentenced to a long jail terms, only weeks after human rights lawyer Anwar al-Bunni is jailed.

Israeli strike

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Mystery site

Israeli forces destroyed what they said was a nuclear facility under construction. Syria says it was an unused military facility

2007 September - Israel carries out an aerial strike against a site in northern Syria that it said was a nuclear facility under construction. In 2011 the UN's IAEA nuclear watchdog decides to report Syria to the UN Security Council over its alleged covert nuclear programme reactor programme at the site.

2008 March - Syria hosts Arab League summit. Many pro-Western states send lower-level delegations in protest at Syria's stance on Lebanon.

2008 April - The US accuses North Korea of having helped Syria to build a secret nuclear reactor at the site bombed by Israel in 2007.

International acceptance

2008 July - President Assad meets French President Nicolas Sarkozy in Paris. The visit signals the end of the diplomatic isolation by the West that followed the assassination of former Lebanese PM Rafik Hariri in 2005. While in Paris, President Assad also meets the recently-elected Lebanese president, Michel Suleiman. The two men agree to work towards the establishing of full diplomatic relations between their countries.

2008 September - Damascus hosts four-way summit between Syria, France, Turkey and Qatar, in a bid to boost efforts towards Middle East peace. Explosion kills 17 on the outskirts of Damascus, the most deadly attack in Syria in several years. Government blames Islamist militants.

Diplomatic thaw continues

2008 October - Syria establishes diplomatic relations with Lebanon for first time since both countries established independence in 1940s.

Syria has a sizeable Christian community

2009 March - Jeffrey Feltman, acting assistant US secretary of state for the Near East, visits Damascus with White House national security aide Daniel Shapiro in first high-level US diplomatic mission for nearly four years. Meets Foreign Minister Walid Muallem.

Trading launches on Syria's stock exchange in a gesture towards liberalising the state-controlled economy.

2009 May - Syrian writer and pro-democracy campaigner Michel Kilo is released from prison after serving three-year sentence.

2009 June - The UN nuclear watchdog, the IAEA, says traces of undeclared man-made uranium have been found at second site in Syria - a reactor in Damascus. The IAEA was investigating US claims that the site destroyed in the 2007 Israeli raid was a nuclear reactor.

2009 July - US special envoy George Mitchell visits for talks with President Assad on Middle East peace.

2009 August - Iraq and Syria recall their envoys in a deepening rift over charges of responsibility for a string of deadly bomb attacks in Baghdad. They restore ties later in 2010.

2010 February - US posts first ambassador to Syria after a five-year break.

2010 May - US renews sanctions against Syria, saying that it supports terrorist groups, seeks weapons of mass destruction and has provided Lebanon's Hezbollah with Scud missiles in violation of UN resolutions.

Nationwide uprising

2011 March - Protests in Damascus and the southern city of Deraa demand the release of political prisoners. Security forces shoot a number of people dead in Deraa, triggering days of violent unrest that steadily spread nationwide over the following months.

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2011 protests

Pro-democracy protests erupted in 2011; the government responded with violence

• Syria: Origins of the uprising
• Bashar al-Assad's inner circle

The government announces some conciliatory measures in an attempt to damp down unrest. . President Assad releases dozens of political prisoners and dismisses the government, and in April lifts the 48-year-old state of emergency. However, he accuses protesters of being Israeli agents.

2011 May - Army tanks enter Deraa, Banyas, Homs and suburbs of Damascus in an effort to crush anti-regime protests. US and European Union tighten sanctions. President Assad announces amnesty for political prisoners.

2011 June - The government says that 120 members of the security forces have been killed by "armed gangs" in the northwestern town of Jisr al-Shughour. Troops besiege the town and more than 10,000 people flee to Turkey. President Assad pledges to start a "national dialogue" on reform.

2011 June - The IAEA nuclear watchdog decides to report Syria to the UN Security Council over its alleged covert nuclear programme reactor programme. The structure housing the alleged reactor was destroyed in an Israeli air raid in 2007.

Opposition organises

2011 July - President Assad sacks the governor of the northern province of Hama after mass demonstration there, eventually sending in troops to restore order at the cost of scores of lives. Opposition activists meet in Istanbul to form a unified opposition.

2011 October - Newly formed Syrian National Council says it has forged a common front of internal and exiled opposition activists. Russia and China veto UN resolution condemning Syria.

2011 November - Arab League votes to suspend Syria, accusing it of failing to implement an Arab peace plan, and imposes sanctions. Army defectors target a military base near Damascus in the Free Syrian Army's most high-profile attack since protests began. Government supporters attack foreign embassies.

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Civil war

The uprising against President Assad gradually turned into a full-scale civil war

• Syria's unwinnable war
• Covert help for rebels

2011 December - Syria agrees to an Arab League initiative allowing Arab observers into the country. Thousand of protesters gather in Homs to greet them, but the League suspends its mission in January because of worsening violence.

Twin suicide bombs outside security buildings in Damascus kill 44, the first in a series of large blasts in the the capital that continue into the following summer. Opposition accuses government of staging these and subsequent attacks.

UN pressure

2012 February - Russia and China block a UN Security Council draft resolution on Syria, and the government steps up the bombardment of Homs and other cities, recapturing the Homs district of Baba Amr the following month. The UN says that more than 7,500 people have died since the security crackdown began.

2012 March - UN Security Council endorses non-binding peace plan drafted by UN envoy Kofi Annan. China and Russia agree to support the plan after an earlier, tougher draft is modified. The UN statement falls short of a formal resolution, and violence continues into the summer.

2012 May - UN Security Council strongly condemns the government's use of heavy weaponry and the militia killing of more than a hundred civilians in Houla, near Homs. France, the UK, Germany, Italy, Spain, Canada and Australia expel senior Syrian diplomats in protest.

2012 June - President Assad tells his reshuffled government that they face "real war", indicating the authorities' conviction that the conflict will be long-lasting and require the sidelining of all other priorities.

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Opposition rifts

Divisions and concern about the role of Islamists have bedevilled the opposition

• Guide to the Syrian opposition

Turkey changes rules of engagement after Syria shoots down a Turkish plane that strayed into its territory, declaring that if Syrian troops approach Turkey's borders they will be seen as a military threat.

2012 July - Free Syria Army blows up three security chiefs in Damascus and seizes Aleppo in the north. A government offensive to recapture the city makes only limited headway.

2012 August - The government suffers further blows. A UN General Assembly resolution demands that President Assad resign, high-level defections gather pace - most notably Prime Minister Riad Hijab - and US President Obama warns that use of chemical weapons would tilt the US towards intervention.

UN appoints veteran Algerian diplomat Lakhdar Brahimi as new UN-Arab League envoy for Syria after resignation of Kofi Annan.

2012 September - The Free Syrian Army claims responsibility for two explosions at the military headquarters in Damascus. The government says four guards were killed in the "suicide attacks".

2012 October - Syria-Turkish tension rises when Syrian mortar fire on a Turkish border town kills five civilians. Turkey returns fire and intercepts a Syrian plane allegedly carrying arms from Russia. Both countries ban each other's planes from their air space.

Fire in Aleppo destroys much of the historic market as fighting and bomb attacks continue in various cities.

UN-brokered ceasefire during the Islamic holiday of Eid al-Adha breaks down as government continues attacks.

2012 November - Several major opposition forces unite as National Coalition for Syrian Revolutionary and Opposition Forces at meeting in Qatar, including the Syrian National Council. Arab League stops short of full recognition. Islamist militias in Aleppo, including the Al-Nusra and Al-Tawhid groups, refuse to join the Coalition, denouncing it as a "conspiracy".

Israeli military fire on Syrian artillery units after several months of occasional shelling from Syrian positions across the Golan Heights, the first such return of fire since the Yom Kippur War of 1973.

2012 December - The US joins Britain, France, Turkey and Gulf states in formally recognising Syria's opposition National Coalition as "the legitimate representative" of the Syrian people.

The conflict in Syria displaced millions of people, many of whom sought refuge in camps in Jordan, Turkey and Lebanon

2013 January - Syria accuses Israeli jets of attacking a military research centre near Damascus, but denies reports that lorries carrying weapons bound for Lebanon were hit. Unverified reports say Israel had targeted an Iranian commander charged with moving weapons of mass destruction to Lebanon.

International donors pledge more than $1.5bn (£950m) to help civilians affected by the conflict in Syria.

2013 March - Syrian warplanes bomb the northern city of Raqqa after rebels seize control. US and Britain pledge non-military aid to rebels, and Britain and France propose lifting European Union arms embargo. Rebel National Coalition elects US-educated technocrat Ghassan Hitto as interim "prime minister".

2013 April - US and Britain demand investigation into reports government forces used chemical weapons. Prime Minister Wael Nader Al-Halqi narrowly escapes death in bomb attack in centre of Damascus.

Opposition National Coalition chairman Moaz al-Khatib resigns, accusing foreign backers of trying to manipulate the group. His successor is veteran socialist George Sabra, leader of the older opposition Syrian National Council.

2013 May - Israeli and Syrian Army exchange fire in the Golan Heights.

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Chemical arms claims

Government forces have faced - and denied - repeated allegations of chemical weapons use

• Chemical weapons allegations
• Syria's chemical weapons stockpile

EU leaders agree not to renew the bloc's arms embargo on Syria, in a step seen as potentially freeing EU countries to arm the rebels.

2013 May-June - Government and allied Hezbollah forces recapture the strategically-important town of Qusair between Homs and the Lebanese border. Rebel commanders complain that arms supplies taper off over international concerns about Islamists in the opposition camp.

2013 July In a leadership overhaul, Saudi-backed Ahmed Jarba replaces interim figure George Sabra as leader of the main opposition National Coalition, defeating a Qatar-backed rival. Interim opposition PM Ghassan Hitto quits, citing his inability to form a government in rebel-held territory.

Rebels say they capture Khan al-Assal, the last major government-held town in the west of Aleppo Province, after two months of successful government offensives.

2013 August - Rebels and Western governments accuse pro-Assad forces of using chemical weapons in an attack that killed more than 300 people near Damascus. The Syrian government says it was the rebels that used chemical weapons. The US and Britain take contingency measures for possible military action. Russia and China warn against any attack on Syria.