What is a polar vortex?

The bitter chill gripping North America is a result of Arctic air that has spilled southwards, and global warming may be a cause, an expert has said.
Arctic air is normally penned in at the roof of the world by a powerful circular wind called the polar vortex, said Dim Coumou, a senior scientist at the Potsdam Institute for Climate Impact Research (PIK) near Berlin.

When the vortex weakens, the air starts heading southwards, bringing exceptional snow and chill to middle latitudes.

The weather shift is also helped by changes in a high altitude wind called the jet stream.

This convection, which usually encircles the northern hemisphere in a robust and predictable fashion, starts to zigzag, creating loops of extremely cold weather or unseasonably mild weather, depending on the location.

“We’ve seen a strong meandering of the jetstream, and the cold air associated with the polar vortex has been moving southwards, and in this case over the eastern parts of Canada and the United States, bringing this extreme cold weather,” said Coumou.

The phenomenon has occurred repeatedly in recent winters, he noted.

What drives the polar vortex is the difference in temperature between the Arctic and mid latitudes, said Coumou.

Once sharp, this differential has blurred in recent years as the Arctic — where temperatures are rising at about twice the global average — warms up, he said.

“We’ve seen this type of cold spell more often lately in recent winters, in Europe but also in the US,” Coumou said in a phone interview.

“The reason why we see these strong meanderings is still not fully settled, but it’s clear that the Arctic has been warming very rapidly. We have good data on this. Arctic temperatures have risen much more than other parts of the globe.”

Last month, European scientists reported that the volume of sea ice in November was around 50 percent greater compared with a year earlier, following a recovery in the Arctic summer.

Despite this bounce-back, sea ice remains at near-record documented lows and its overall trend is one of retreat, they said.

Coumou cautioned that Arctic sea ice “is just one of the important factors” behind disruption of the polar vortex”.

“Other factors include snow cover, stratospheric warming events or other short-lived phenomena,” he said.

Other specialists said the link between warming and the spillover of Arctic air was still debated.

“There is no consensus,” said Francois Gourand, a forecaster at Meteo France, the French national meteorological agency.

“The melting of sea ice can have an impact on atmospheric circulation but these effects are complex and hard to pin down,” he said.

“The overall trend of the sea ice is downwards, yet in Europe we can have mild winters sometimes, or cold winters — there doesn’t seem to be a clear link.”

Fish oil extracted from plant seeds

Maturing Camelina seed capsules
The oil from the seeds is now being used in salmon feeding trials

Scientists have genetically engineered plant seeds to contain Omega-3 fatty acids normally found in oily fish.

Seeds from Camelina sativa (false flax) plants were modified using genes from microalgae – the primary organisms that produce these fatty acids.

The oil has now been incorporated into salmon feed to assess whether it’s a viable alternative to wild fish oils.

It is hoped that the transgenic plants will provide a more environmentally friendly source of the oil.

The work is published in Plant journal.

Fish do not produce Omega-3 naturally, rather they get it from the algae in the marine environment which then moves up the food chain.

Farmed salmon are therefore given feed containing fish oil in order to mimic their natural feeding habits and crucially, so that they contain the essential fatty acids we need in our diet.

Johnathan Napier, associate director at Rothamsted Research, said that the finished product he helped produce represented a “sustainable, terrestrial source of fish oils, which is really exciting”.

2.5 Litres of GM Camelina oil
Oil containing long-chain Omega-3 has been extracted from the seeds of Camelina plants

“One of the problems with the current supplies of fish oils is that fish stocks are a diminishing natural resource,” Prof Napier told BBC Radio 4’s Inside Science programme.

“What we’re trying to do here is provide an alternative, sustainable source of fish oils.”

Although Omega-3 can be obtained from some nuts, seeds and vegetables, it is only in the marine environment, in algae and fish, where the long-chain forms of Omega-3 are found – docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which we need in our diet.

Prof Napier said that the next step was to see if the oil from the transgenic plants had similar properties to natural fish oil.

Camelina plants

“Ultimately we think it could be really useful as a contribution to human health and nutrition as an alternative source of fish oils, but that’s something that needs to be tested and evaluated by the appropriate regulators,” he said.

“It’s still an experiment, it’s a very big experiment but at the moment there’s no possibility this is going to enter the human food chain.”

Commenting on the work, Colin Lazarus from Bristol University, who has previously put genes from fatty acids into other plants, said he hoped the oil would be a “standard bearer for introducing GM to the industry”.

“I’m delighted the work has come this far. 10 years ago we demonstrated that higher plants could produce these polyunsaturated fatty acids, but we didn’t attempt to direct the synthesis to seeds.

Close-up of mature Camelina seed capsules

“What’s not realised generally is that fish don’t make these oils themselves. Genetic modification and sustainability are clearly not mutually exclusive.”

A team at the University of Stirling has already incorporated the oil into salmon feed. It will now analyse the fish to see if the properties are the same as those given their usual feed.

Douglas Tocher, from the University of Stirling’s Institute of Aquaculture, said that on first glance the composition of the fish from the feeding trials was the same.

“There isn’t enough fish meal and fish oil being produced in the world to sustain the great increase we’re seeing in aquaculture production. The beauty and great breakthrough is that we are now looking at an alternative to fish oil.

“The conventional vegetable oils are good at feeding fish but do not supply the long-chain Omega-3 that we require fish to have in order for them to be a nutritionally high quality product,” Prof Tocher told BBC News.

‘Superlens’ extends range of wireless power transfer

Inventor Nikola Tesla imagined the technology to transmit energy through thin air almost a century ago, but experimental attempts at the feat have so far resulted in cumbersome devices that only work over very small distances. But now, Duke University researchers have demonstrated the feasibility of wireless power transfer using low-frequency magnetic fields over distances much larger than the size of the transmitter and receiver.

The advance comes from a team of researchers in Duke’s Pratt School of Engineering, who used metamaterials to create a “superlens” that focuses magnetic fields. The superlens translates the magnetic field emanating from one power coil onto its twin nearly a foot away, inducing an electric current in the receiving coil.

The experiment was the first time such a scheme has successfully sent power through the air with an efficiency many times greater than what could be achieved with the same setup minus the superlens.

The results, an outcome of a partnership with the Toyota Research Institute of North America, appear online in Scientific Reports on Jan. 10.

“For the first time we have demonstrated that the efficiency of magneto-inductive wireless power transfer can be enhanced over distances many times larger than the size of the receiver and transmitter,” said Yaroslav Urzhumov, assistant research professor of electrical and computer engineering at Duke University. “This is important because if this technology is to become a part of everyday life, it must conform to the dimensions of today’s pocket-sized mobile electronics.”

In the experiment, Yaroslav and the joint Duke-Toyota team created a square superlens, which looks like a few dozen giant Rubik’s cubes stacked together. Both the exterior and interior walls of the hollow blocks are intricately etched with a spiraling copper wire reminiscent of a microchip. The geometry of the coils and their repetitive nature form a metamaterial that interacts with magnetic fields in such a way that the fields are transmitted and confined into a narrow cone in which the power intensity is much higher.

On one side of the superlens, the researchers placed a small copper coil with an alternating electric current running through it, which creates a magnetic field around the coil. That field, however, drops in intensity and power transfer efficiency extremely quickly, the further away it gets.

A closer look at the metamaterial “superlens” that beams electromagnetic fields to increase the range of wireless power transfers. The squares are actually long coils of copper wire reminiscent of the surface of a microchip. Credit: Duke University

“If your electromagnet is one inch in diameter, you get almost no power just three inches away,” said Urzhumov. “You only get about 0.1 percent of what’s inside the coil.” But with the superlens in place, he explained, the is focused nearly a foot away with enough strength to induce noticeable in an identically sized receiver coil.

Urzhumov noted that metamaterial-enhanced wireless power demonstrations have been made before at a research laboratory of Mitsubishi Electric, but with one important caveat: the distance the power was transmitted was roughly the same as the diameter of the power coils. In such a setup, the coils would have to be quite large to work over any appreciable distance.

“It’s actually easy to increase the power transfer distance by simply increasing the size of the coils,” explained Urzhumov. “That quickly becomes impractical, because of space limitations in any realistic scenario. We want to be able to use small-size sources and/or receivers, and that’s what the superlens enables us to do.”

Each side of each constituent cube of the “superlens” is set with a long, spiraling copper coil. The end of each coil is connected to its twin on the reverse side of the wall. Credit: Courtesy of Guy Lipworth, graduate student researcher at Duke University

Urzhumov said magnetic fields have distinct advantages over the use of electric fields for .

“Most materials don’t absorb magnetic fields very much, making them much safer than electric fields,” he said. “In fact, the FCC approves the use of 3-Tesla magnetic fields for medical imaging, which are absolutely enormous relative to what we might need for powering consumer electronics. The technology is being designed with this increased safety in mind.”


Going forward, Urzhumov wants to drastically upgrade the system to make it more suitable for realistic power transfer scenarios, such as charging mobile devices as they move around in a room. He plans to build a dynamically tunable superlens, which can control the direction of its focused power cone.

“The true functionality that consumers want and expect from a useful system is the ability to charge a device wherever it is – not simply to charge it without a cable,” said Urzhumov. “Previous commercial products like the PowerMat™ have not become a standard solution exactly for that reason; they lock the user to a certain area or region where transmission works, which, in effect, puts invisible strings on the device and hence on the user. It is those strings—not just the wires—that we want to get rid of.”

Yoga: a beginner’s guide to the different styles

Whether you want to relax, have a workout or get in touch with your spiritual side, there is a yoga class to suit you. And you don’t even have to be bendy …
Yoga class

Yoga class. Photograph: Boston Globe via Getty Images

The myriad benefits of yoga – including lower blood pressure, increased strength and bone density and reduced anxiety – should be enough to get anyone on the mat. However, as a yoga teacher I meet many people who hesitate to embrace this ancient form of fitness due to some pervasive myths. Yoga is too slow and boring; it’s practised in stuffy, incense-filled rooms – or in 90C heat; it’s just for girls and people who are into chanting. And – most misguided of all – yoga is only for the flexible.

The truth is that there is a class to suit you whatever your body type or temperament. Yoga develops strength and balance as well as flexibility – the latter is a consequence of practising yoga, not a prerequisite. No one has turned up to their first yoga class (unless they were a dancer or a gymnast) able to execute advanced yoga poses.

All yoga styles create a feeling of lightness, ease and relaxation. But to get the most benefit and the most enjoyment, you need to find a yoga style and a teacher that suits you. For example, if you’re already doing lots of strength training your best choice is likely to be a yoga style that focuses more on flexibility. That way, you can balance your fitness routine. Perhaps try yin or hatha yoga. Those who have an injury or live with a chronic medical condition such as arthritis might want to try Iyengar yoga, or one-to-one sessions with a teacher where you will be able to focus on alignment and your unique needs. If you are drawn to experience the spiritual side, you could try jivamukti. And for those who are relatively healthy and want a challenge, ashtanga vinyasa or vinyasa flow might be a good choice.

Before you make a decision, try a few of the most common styles of yoga that you might see on a yoga studio (or gym) timetable. Some classes – marked general or open level – are suitable for all. This is how I started my yoga journey – by watching and copying. When you think you’ve settled on a style of yoga you enjoy, try a few different teachers. All teachers have their own unique focus based on their personalities, their own yoga practice and where and with whom they’ve trained.

Yoga can be expensive, especially in the larger cities. The most cost-effective way is to take advantage of studio offers. Newcomers can sign up for deals such as £20 for 14 consecutive days of classes. Aim to go to a class every few days – later, you can consider committing to a course. Regular attendance is needed to really reap the benefits. A good teacher will not do his or her own practice at the front of the room. They should be roaming around adjusting, correcting and giving alternatives to people who cannot do the full pose or have an injury. They should be helping you to focus on what you can do, rather than what you can’t. A good teacher won’t expect you to be anything other than a beginner and they want you to have – and enjoy – a beginner’s experience.

A guide to the most common yoga styles

Yoga instructor Tao Porchon-Lynch, 93
Iyengar yoga

Iyengar and ashtanga yoga come from the same lineage – the teachers who developed these styles (BKS Iyengar and the late Pattabhi Jois) were both taught by Tirumalai Krishnamacharya. Many of the asanas (postures) are the same, but the approach is different. Iyengar yoga is great for learning the subtleties of correct alignment. Props – belts, blocks and pillow-like bolsters – help beginners get into poses with correct alignment, even when they’re new to them, injured or simply stiff. Anusara yoga is a more modern form of Iyengar.

Ashtanga yoga

Ashtanga is a more vigorous style of yoga. It offers a series of poses, each held for only five breaths and punctuated by a half sun salutation to keep up the pace. You can either attend a regular class or the more traditional Mysore style (see below).

Mysore style

Ashtanga yoga taught one-to-one in a group setting. Students turn up at any time within a three-hour window to do their own practice as taught by their teacher. This is my preferred style of learning yoga and, I think, the safest and most traditional. You go at your own pace, on your own breath.

Vinyasa flow

Teachers lead classes that flow from one pose to the next without stopping to talk about the finer points of each pose. That way, students come away with a good workout as well as a yoga experience. If you’re new to yoga, it is a good idea to take a few classes in a slower style of yoga first to get a feel for the poses. Vinyasa flow is really an umbrella term for many other styles. Some studios call it flow yoga, flow-style yoga, dynamic yoga or vinyasa flow. It is influenced by ashtanga yoga.

Bikram yoga

Bikram yoga is the favourite of anyone who loves to sweat. It was created by Indian yogi Bikram Choudhury in the early 1970s. He designed a sequence of 26 yoga poses to stretch and strengthen the muscles as well as compress and “rinse” the organs of the body. The poses are done in a heated room to facilitate the release of toxins. Every bikram class you go to, anywhere in the world, follows the same sequence of 26 poses.

Kundalini yoga

Kundalini yoga was designed to awaken energy in the spine. Kundalini yoga classes include meditation, breathing techniques such as alternate nostril breathing, and chanting, as well as yoga postures.

Hatha yoga

Hatha yoga really just means the physical practice of yoga (asanas as opposed to, say, chanting). Hatha yoga now commonly refers to a class that is not so flowing and bypasses the various traditions of yoga to focus on the asanas that are common to all. It is often a gentle yoga class.

Yin yoga

Yin yoga comes from the Taoist tradition and focuses on passive, seated postures that target the connective tissues in the hips, pelvis and lower spine. Poses are held for anywhere between one and 10 minutes. The aim is to increase flexibility and encourage a feeling of release and letting go. It is a wonderful way to learn the basics of meditation and stilling the mind. As such, it is ideal for athletic types who need to release tension in overworked joints, and it is also good for those who need to relax.

Restorative yoga

Restorative yoga is all about healing the mind and body through simple poses often held for as long as 20 minutes, with the help of props such as bolsters, pillows and straps. It is similar to yin yoga, but with less emphasis on flexibility and more on relaxing.

Jivamukti yoga

Founded in 1984 by David Life and Sharon Gannon, Jivamukti means “liberation while living”. This is a vinyasa-style practice with themed classes, often including chanting, music and scripture readings. Jivamukti teachers encourage students to apply yogic philosophy to their daily life.

Y chromosome is not doomed to shrivel away to nothing, say researchers

Despite concerns it may be shrinking, male sex chromosome is likely to remain in rude health for many millions of years to come
Mural featuring Genghis Khan and his court

One explanation for the lack of genetic variation on the Y chromosome is the Genghis Khan effect, with a small number of men fathering many children. Photograph: Alamy

Reports of the coming death of the male sex chromosome are greatly exaggerated, say scientists, whose work will raise a collective cheer from at least half the population. The fate of the Y chromosome, which carries the genetic switch that sends a developing embryo down the route to maleness, has been questioned since scientists first discovered that it had lost more than 90% of its genes over millions of years of evolution.

The steady withering of the Y has led some to claim that it might vanish completely over the next five million years, leaving humans to join the Okinawa spiny male rat on the list of species that make do without a sex chromosome. But that unsettling prospect is dismissed in research published on Friday by scientists at the University of California, Berkeley. Having studied the genetic makeup of 16 men, they conclude that natural selection is not about to cast the shrunken male chromosome on the evolutionary scrapheap.

The Y chromosome has shrunk over time because, unlike every other chromosome in the human body, it has no partner. This means it cannot easily be repaired when harmful mutations occur. Typically, people have 23 pairs of chromosomes including two that govern sex, which areX and Y in males, or two Xs in females. The numbers vary in some genetic disorders.Most chromosomes can repair damage that arises from mutations by swapping DNA with their opposite number, a process called recombination. But the Y is always inherited alone, so has no partner to swap with. As such, the damage builds up until the DNA is discarded, leaving the chromosome that much smaller. Today, the Y carries only 27 genes that are used to make proteins, compared with around 800 on the X chromosome. A few hundred million years ago, early versions of the X and Y were the same size.

Writing in the journal Plos Genetics,the Berkeley researchers describe the genetic diversity of Y chromosomes in eight European and eight African men. The variation was tiny, and suggests that the Y chromosome has been pared down to its bare essentials by “purifying selection”An alternative explanation for the low genetic variation of Y chromosomes is that a minority of men had a high proportion of children, passing on fewer Y chromosome variants to each successive generation. At the extreme is the Genghis Khan effect, named after the Mongol leader who fathered so many sons, his Y chromosome lives on in around 0.5% of the male global population. But the study found that if this were the driving force for low genetic variation on the Y chromosome, fewer than one in four men would have fathered children in the course of human history.

According to the researchers, all 27 genes on the Y chromosome, nearly half of which are poorly understood, are acted on by purifying selection. The fact they’re still here suggests they have a valuable role to play in successful breeding.

“Natural selection is acting on the Y chromosome and has maintained the genes pretty well,” said Melissa Wilson Sayres, an evolutionary biologist. “All the evidence points toward it not disappearing.”

The Berkeley team now hopes to study more Y chromosomes to learn whether the genes are subjected to “positive selection”, whereby beneficial mutations spread through the population.

Smartphones replace keys in smart door locks.

Gabriel Bestard-Ribas got tired of his house keys scratching his smartphone in his pocket, so he combined them.

The result was a Goji lock, which senses when a resident’s  is near and not only unlocks a door but greets the resident by name.

It’s just one of the trend of “smart locks” on display at the Consumer Electronics Show that ends here Friday.

“My keys were always scratching my phone, so I thought why not build them in,” said Bestard-Ribas, founder and chief executive of San Francisco startup Goji.

His creation fuses mobile Internet technology with centuries old lock mechanics. A free Goji application installed in smartphones uses Bluetooth connectivity to let the lock know a person is near and, if it is a resident or someone given a “digital key,” a personalized welcome message displays and the path is opened.

A camera built into the lock takes a picture of whoever is arriving. Images of visitors as well as alerts regarding entry are relayed to residents’ smartphones through home wireless Internet connections.

“It is about allowing you to feel confidence and control over your home access,” Bestard-Ribas told AFP. “We have all lost keys or given them to someone who left our sight; we don’t know if copies were made.”

Temporary digital keys, restricting use to specified time periods, can be emailed to house cleaners, dog walkers, or others who may need to visit homes. The locks were available for order online at gojiaccess.com at a price of $299 each, and will begin shipping in March.

Veteran lock makers Kwikset and Schlage were also showing off smart locks at CES.

A Kwikset Kevo lock senses when a resident’s smartphone is near and then opens when the person touches what appears to be an ordinary deadbolt in a door.

“As long as you have your phone in our pocket, or in your purse, you touch the deadbolt and in about a second it will lock or unlock,” said Phil Dumas, president of UniKey, whose technology was built into Kevo.

“It can even tell what side of the door you are on, so you can be on the inside and a bad guy can touch the door and it won’t unlock.”

Kevo launched late last year at an array of US retailers with an application tailored for iPhones, and UniKey was waiting for a software update from Google to release one compatible with Android-powered handsets.

Schlage’s touch-screen deadbolt let people unlock doors to their homes remotely using their smartphones, and featured built-in alarms that shriek if incorrect codes are entered too many times.

Each of the locks provided ways to offer limited access by granting people temporary keys or codes, and promised records of who entered and when delivered to smartphones.

“Your  is linked to the Wi-Fi of your home, and your home automation system, so you could manage your home from anywhere in the world,” Bestard-Ribas said. “This is a really life-changing event that is happening now-a-days.”

For folks interested in seeing who is on their doorstep without having to change locks, there was SkyBell.

The Internet Age doorbell connects to the same wires as its simpler predecessors, but has a built in camera and synchs to Wi-Fi to stream real-time video of who is ringing to a resident’s smartphone.

It also has motion sensing and night-vision, so it can transmit images even when visitors arrive in darkness, according to SkyBell’s Kelly Stewart.

“You can see and hear and talk to them,” Stewart said, of visitors both welcome and not. “If a robber is in front of your house the motion-sensor will alert you, or if your daughter tries to sneak in after her curfew.”