Traditional robots are made of components and rigid materials like you might see on an automotive assembly line
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Traditional robots are made of components and rigid materials like you might see on an automotive assembly line
The world particle-physics community has convened in Vienna for the 2015 European Physical Society Conference on High Energy Physics (EPS-HEP2015), where the latest results in the field are being presented and discussed. These include the first results from Run 2 of the Large Hadron Collider (LHC) at CERN which are being presented for the very first time, less than two months after the experiments started to take data at the unprecedented energy of 13 TeV, following a two-year long shutdown.
"It is much too early to expect any discovery, we will have to be patient,” said CERN Director-General Rolf Heuer. “Nevertheless, the LHC experiments have already recorded 100 times more data for the summer conferences this year than they had around the same time after the LHC started up at 7 TeV in 2010. We can sense a fantastic pioneering spirit as the physicists are looking at completely new data at an unexplored energy.”
As for any machine exploring a new energy frontier, operators at the LHC face many challenges on a daily basis. Since the start of Run 2, they have been gradually increasing the intensity of the LHC’s two beams, which travel in opposite directions around the 27-kilometre ring at almost the speed of light. The LHC has run at the record high energy with each beam containing up to 476 bunches of 100 billion protons, delivering collisions every 50 nanoseconds. In the coming days, the intensity should increase further with a new rhythm of 25 nanoseconds. After a planned technical stop in early September, the teams will also be able to increase the number of bunches with the goal of reaching more than 2000 bunches per beam by the end of 2015.
“During the hardware-commissioning phase, we have learnt to manage carefully the huge energy stored in the magnets. Now with beam commissioning we have to learn progressively how to store and handle the beam energy,” said CERN Director of Accelerators and Technology Frédérick Bordry. “Our goal for 2015 is to reach the nominal performance of the LHC at 13 TeV so as to exploit its potential from 2016 to 2018.”
The LHC has already delivered over 10 thousand billion collisions to the large experiments since the start of Run 2. This has allowed the LHC collaborations to measure a full suite of detector performance parameters that demonstrate the readiness of the experiments for discovery physics and precision measurements. The next step was to confirm the Standard Model at the new energy of 13 TeV. After only a few weeks of data taking, the experiments have now “rediscovered” all of the known fundamental particles, apart from the so-called Higgs boson, for which more data are still required. The collaborations are thus ready to test the Standard Model at 13 TeV and the hope is to find evidence of new physics beyond this well-established theory.
At the EPS-HEP2015 conference, the ATLAS and CMS collaborations presented the first measurements at 13 TeV on the production of charged strongly-interacting particles (hadrons). CMS has already submitted this result for publication – the first for the new energy region. Such measurements are important in understanding the basic production mechanism for hadrons.
The LHC experiments have also made the first measurements of cross-sections at 13 TeV. Cross-sections are quantities related to the probability for particles to interact, and their measurement is essential for identifying any new phenomena. For example, ATLAS has measured the cross-section for the production of pairs of top quarks and antiquarks, which is some three times higher at 13 TeV than at the energy of Run 1.
In addition, the conference is providing the opportunity for all of the LHC experiments to present many new or final results from the first run at the LHC. These include searches for dark matter, supersymmetric and other exotic particles, as well as new precision measurements of Standard Model processes.
In this respect, one highlight in Vienna is the presentation for the first time at an international conference of the recent discovery by the LHCb experiment of a new class of particles known as pentaquarks (see press release). LHCb also published today in Nature Physics a result confirming that a certain decay involving the weak force happens with beauty quarks having a “left-handed” spin. This result is consistent with the Standard Model, in contrast with previous measurements that allowed for a right-handed contribution.
In other highlights from Run 1, the ALICE and LHCb experiments have new results on long-range correlations in proton–lead collisions. The latest measurements show that the so-called “ridges” seen in the most violent collisions span across even larger longitudinal distances. In Run 2 data, ATLAS reported that the near-side ridge is seen in 13 TeV proton–proton collisions, with characteristics very similar to those observed by CMS in Run 1.
On Tuesday, New Horizons phoned home to inform NASA that it successfully executed its flyby of Pluto, coming within 12,500km (7,767mi) of the dwarf planet's surface. Having collected a ton of data, the spacecraft has begun the long process of transmitting it all back to Earth.
Among the first images transmitted back to NASA was a stunning, high-resolution image of Pluto's surface. Pictured above, the image covers an area near Pluto's equator and shows a mountain range with peaks as high as 3,350m (11,000 feet). There's also a noticeable lack of impact craters, which indicates that the surface of Pluto is relatively young. "This is one of the youngest surfaces we’ve ever seen in the solar system," said Jeff Moore of New Horizons’ Geology, Geophysics and Imaging Team.
The New Horizons team estimated the age of the mountains at 100 million years old, and it's thought that the area shown above, which covers less than one percent of Pluto's surface, depicts a geologically active area.
When you spill a bit of water onto a tabletop, the puddle spreads — and then stops, leaving
A healthy aversion to snakes might be useful in the jungle, but a ramped-up phobia of them that has you running screaming from garden hoses is obviously maladaptive in suburbia. And then there are phobias that seem to lack rational explanation: an aversion to pigeons, avoiding anything to do with the number 13, to fear of the color yellow.
"Fear mechanisms have helped us survive for millions of years," says UC Davis neuroscientist and psychologist Philippe Goldin. But even a natural mechanism can become twisted into something strange.
Where fear lies
The primary seat of fear in the brain lies in the amygdala, two almond-shaped clusters of neurons nestled deep in the temporal lobe. Scientists have found that there are actually two fear-related pathways involving the amygdala — one more direct route from a stimulus, and another, longer way that first passes through the cortex, where much of your higher-order thinking happens.
Either way, tripping the amygdala's alarm "puts you in a mode where you are prepared for action," says Nouchine Hadjikhani, a Harvard University neuroscientist.
Registering a fear-causing stimulus can happen at lightning speed; Swedish scientist Arne Ohman and colleagues have found that flashing images of snakes or spiders so quickly that people are not consciously aware of seeing a snake or spider can still trigger a fear response. Interestingly, when these high-speed stimuli flash by, people's amygdalas respond equally fearfully to all stimuli — so an arachnophobic person would be equally unnerved by images of spiders and snakes. But when the images are shown slowly enough for people to comprehend them, their amygdala lights up only in response to their specific phobia (spiders, say). Our amygdalas seem to be primed to react quickly to anything that seems threatening, but once there's enough time for other, more sober parts of the brain to weigh in, we can filter out what's not worth getting worked up about.
The pathways leading out of the amygdala lead to lots of other brain regions; one particularly important output for the fear response is the connection to the hypothalamus. This brain region regulates the production and secretion of hormones like adrenaline, a key player in the fight-or-flight response. "The amygdala is one of the most highly interconnected regions of the brain, and that makes sense," Goldin says. "Arousal — positive or negative — activates many different mechanisms."
But there are other brain structures involved in fear, too, as demonstrated by studies of people with a rare genetic disorder called Urbach-Wieth disease, which causes the amygdala to shrivel up. In experiments conducted by University of Iowa researchers, Urbach-Wieth patients were unmoved by horror movies or exposure to large spiders, but did experience terror when they were asked to inhale a carbon dioxide mixture through a mask — which simulates suffocation. Therefore, there must be some amygdala-independent fear pathway; further research is needed to trace that trail through the brain.
How fear takes hold: Through direct association
Just as Pavlov's dogs salivated at the sound of a dinner bell, the power of association can turn even the most relatively innocuous thing into a phobia. Scientists are able to induce phobias of certain sounds or smells in lab rats by administering a painful shock in conjunction with that stimulus. Eventually the rodents are hard-wired to associate that scent or sound with pain, and remain fearful of that trigger.
How fear takes hold: Through indirect association
The process of how phobias form by association in humans is, of course, more subtle than a guy in a lab coat tormenting you. University of North Dakota psychologist Ric Ferraro invites you to consider someone with a phobia of the color green — how could something like that have formed? Any number of ways; it could have been that, as a child, "they could have fallen down, got green grass on their clothes, and their mom or dad yelled at them so now they associate fear with the color green," Ferraro told the UND news service.
How fear takes hold: Through fear transference
There's also a social component to some human phobias. We learn a lot of our behavior through observation, and this includes fear: "You see your mother panicking frantically in response to a wasp when you're a child, you'll likely be afraid of wasps too," neuroscientist Dean Burnett wrote in the Guardian.
How fear takes hold: Through instruction
We may even convince ourselves that something's incredibly scary thanks to receiving information (whether true or false) that something is threatening, a uniquely human phenomenon called instructional fear acquisition. A team led by New York University researcher Elizabeth Phelps found that if a person is told they might get a shock when a square of a certain color flashes on a screen, their amygdala will activate even without the shock, possibly because the brain creates an abstract representation of the pain. In a more real-world setting, instructional fear acquisition could be the reason you get the urge to avoid showers or flocks of birds after seeing a Hitchcock film.
How fear takes hold: Through inheritance
Another, less-well-understood factor in our fear is epigenetics — heritable changes outside of the changes to our genetic code. Goldin thinks that epigenetics could potentially explain a lot of the variance among people in terms of how they respond to and control their own fears.
"You have had, from birth to this moment, this whole trajectory of learning that sculpts your brain," Goldin says. "In addition to that, there's genetic factors that come from your mom and dad and beyond, even your grandparents, great-grandparents…things that happened to them are influencing what parts of your genetic code are or are not activated."
Evidence bears this out: In 2013, researchers published a paper in the journal Nature Neuroscience about an experiment in which they trained mice to associate the smell of the compound acetophenone (an odor another researcher describes as something like orange blossoms plus artificial cherry flavor) with pain. The scientists then saw that the offspring of those mice showed more signs of agitation and fear at the scent of acetophenone than control mice.
What can be done to fight the fear
Though fears can stem from many different sources, therapy can help undo the psychological knots of phobias. The treatment of choice these days is exposure-based cognitive behavioral therapy, in which a person works with a therapist to unlock the thought patterns underlying their fears, and also gradually learns to tolerate exposure to the phobic stimulus. An arachnophobe may talk about the realistic level of danger that spiders actually pose, then look at pictures of spiders, then get closer and closer to an actual spider.
So, if you shudder at snakes, pale at the sight of pigeons, or come undone when a clown honks his malevolent horn, don't despair. Your brain might be wired for fear, but it can be rewired just the same.
Researchers at the National Institute of Standards and Technology (NIST) have come up with a way to shrink
The world population, which stood at 5 billion in 1950, is predicted to increase to 10.5 billion by