Apple's iPad Pro looks good, but who needs a phone with a 13" screen?

Monica Davey/EPA

Apple’s annual September keynote as usual brings hardware changes, software updates and the occasional surprise.

Rumours of a larger iPad Pro were proved true: the significantly larger 12.9 inch iPad with upgraded ARM A9X processor and faster graphics and internal components is being sold as a device on which desktop-class applications could run.

This is supported with a stylus and keyboard (sold separately in typical Apple fashion) that essentially converts the iPad Pro into a laptop. The stylus, dubbed Apple Pencil, has provoked comment as Steve Jobs had expressed his distaste for them in the past. The Pencil features hand writing recognition software, and improvements to iOS finally allow multitasking by splitting the screen between two apps.

However, with prices starting at an eye-watering US$799, there will be many who think that this won’t light a fire under tablet sales, which have been flat. For example, Amazon have taken the opposite approach, aiming for the bottom end of the market with a US$50 tablet subsidised by purchases made through Amazon’s services.

There may be iPad sales in education, and in retail where they are often used as point of sale devices, but in business the iPad faces considerable competition. For example, the iPad Pro bears an uncanny similarity to Microsoft’s own convertible tablet/laptop device, the Surface Pro, in cost and size and style. But the big difference is that Surface comes with a full operating system, Windows 10: few will take Apple’s claims that the iPad Pro can run desktop-class applications for professional use while it’s running the stripped-down iOS operating system originally designed for phones, instead of the full OS X as found on Macbooks and iMacs.

Microsoft’s Surface Pro tablet, keyboard and stylus combo. Microsoft

Apple’s iPad Pro - spot the similarity? Beck Diefenbach/Reuters

 

 

 

 

 

A surprise was the appearance of Microsoft staff on stage to demonstrate Microsoft Office apps running on the iPad – something greeted with a stunned silence in the auditorium. Microsoft Office has been updated to support the stylus, and the invitation to appear at such a high-profile Apple event shows the extent to which Microsoft has been pouring money and effort into ensuring its software suites are cross-platform, rather than tied to Microsoft Windows. Another visitor to the stage was Adobe, whose reps showed off new design tools with the stylus – which all suggests an outbreak of corporate peace between the firms.

Pushing Apple TV into the home

The Apple TV finally gets a long-awaited upgrade, a wait during which many competing devices have appeared such as NOW TV, Roku, or Google’s Chromecast. Originally classified as a “media extender”, Steve Jobs called the Apple TV a “hobby” when introduced in 2007, but with this update Apple has refreshed the device, reorienting it to support the app ecosystem that has thrived elsewhere.

The new Apple TV features a new operating system tvOS, making use of the extensive iPhone/iPad developer tools and software already available. Boasting a much higher hardware specification, the Apple TV now runs apps and games, provides a new interface and a touch-enabled remote that can also process audio commands through the Siri digital assistant voice recognition system. With this a user can use their voice to search for content across multiple television networks.

It should be easy to port existing iPad/iPhone applications to the TV, bringing an unparalleled range of services compared to the competition. The surge in streaming services from Amazon and Netflix has sidelined Apple to some extent, so it will be interesting to see whether reorienting the device around apps will increase Apple’s footprint in this space. Sony and Microsoft should be worried that the massive back catalogue of iOS games can now be used in the living room through Apple TV. Prices start from US$149, available from October.

Phone and Watch

An update to the Watch, dubbed WatchOS2, arrives later this month and features updated accessories, colours and straps. The update will give apps direct access to the hardware, allowing developers to write full native applications for that are more independent of the iPhone, to which the Watch has so far played second fiddle.

The iPhone 6S and iPhone 6SPlus are unchanged externally, but Apple claims internal upgrades including a 12 megapixel capable camera, faster A9 processor and a Force Touch capable screen, which responds to varying degrees of pressure. This is still a new tech, for which capable software has yet to be written.

Finally, as signalled in the developer conference earlier in the year, owners of older devices will get access to new features when iOS 9 is launched very soon. An incremental upgrade, nevertheless it offers features many users have been calling for and will provide a significant increase in speed and features for older devices.

It’s unlikely these changes will lead to the extraordinary sales achieved with the larger iPhones last year, so it may provide an opportunity for other manufacturers to play catch-up – improving their hardware and services which Apple has always claimed is what differentiates them from the competition in a crowded market.

Explainer: how do archaeologists discover forgotten ancient monuments?

Amazing stone age ingenuity. Rubbish fence. Ludwig Boltzmann Institute

The popular image of an archaeologist is someone who spends most of their time on their knees painstakingly excavating sites. Although excavation is still one of archaeology’s principal research methods, it is not without problems: it is slow, expensive and can cover only relatively small areas of a site. Most problematic of all, it destroys much of the very evidence we rely upon.

In reality, archaeologists use a wide variety of other techniques to investigate both individual sites and whole landscapes. For example, aerial photography of a farmed field can reveal hidden details because crops ripen differently in areas above buried walls or ditches. Meanwhile the systematic collection of artefacts from the surface of ploughed fields can provide valuable artefactual evidence.

How can archaeologists see what’s underground?

One suite of techniques available to archaeologists is geophysical survey (or “geofizz” to fans of the TV show Time Team). Of the many geophysical techniques that exist, archaeologists generally make use of four: magnetic gradiometry, earth resistance, ground penetrating radar (GPR) and magnetic susceptibility. Each technique measures some aspect of the ground below the surface. By taking many readings on a regular grid and plotting the results, information about the archaeological site can be gained without having to dig it up.

The basic techniques were largely developed in the late 1950s–60s but their use has been revolutionised by the power of modern computing which enables us to collect and process huge amounts of data quickly, and by modern surveying techniques.

High-accuracy differential GPS is able to provide coordinates accurate to about 10mm. As a result, we are now able to build towed arrays that can survey large landscapes quickly and accurately. This is what recently enabled archaeologists to discover the huge line of stones at Durrington Walls near Stonehenge, revealing them to be part of the largest surviving stone monument underneath a bank ever discovered in Britain.

But many surveys are still conducted using hand-operated machines, and still provide exciting results such as those obtained this summer at Verulamium, Hertfordshire, by the Community Archaeology Geophysics Group. The survey has revealed rich town houses and more modest dwellings, roads, a temple and possibly even the aqueduct which supplied some of the town’s water.

Around Stonehenge: undeground overground Ludwig Boltzmann Institute

What are the techniques they use?

Magnetic gradiometry measures local variations in the Earth’s magnetic field. There are two sources of magnetism of interest to archaeologists: thermoremanence and magnetic susceptibility. In the former case, weakly magnetic materials that have been subjected to intense heat become permanently magnetised due to the influence of Earth’s magnetic field as they cool, and then can be more easily detected. Good examples include features such as pottery kilns.

In the latter case, archaeologists can measure the magnetic response of a sample to the Earth’s magnetic field. Soils and sediments in particular can be magnetically enhanced through low-temperature firing, organic fermentation and other processes. Often, negative features such as pits and ditches contain such magnetically enhanced soils and are detectable with a magnetometer.

A four-sensor magnetometer in action at Verulamium. Kris Lockyear

In an earth resistance survey, an electric current is passed through the ground and the resistance is measured. In order to conduct an electric current, the soil must contain water and salt. In practice, the technique allows archaeologists to measure variations in the water present in the ground. Features such as solid walls and surfaced roads will usually have low moisture content and thus a high resistance. Subsurface features that trap moisture, such as ditches and pits, will usually have low resistance, although these are less easily detected.

An earth resistance survey in progress at Verulamium. Kris Lockyear

GPR works by transmitting a very-high frequency radio pulse into the ground. Some of the pulse will be reflected back from surfaces of different layers of material in the ground such as wall tops or floors. By measuring the time taken for the pulse to return, it is possible to estimate the depth of the change and so of the feature.

A GPR in action at Verulamium. Kris Lockyear

Some of the pulse will continue deeper into the ground and be reflected by other changes. By moving the antenna across the ground surface in a linear transect, it is possible to build-up a radargram, essentially an image of the reflections along the line of the transect. By taking multiple closely spaced transects and stacking them into a cube in the software, we can create horizontal “time slices” images of the pattern of reflections at different depths.

A magnetic susceptibility survey in progress at Ogallala, Nebraska. Kris Lockyear

Magnetic susceptibility survey subjects a relatively small volume of soil to a magnetic field and measures the induced magnetic response. Whereas in gradiometry we rely on the Earth’s magnetic field to induce the response, this type of survey actively creates the response and provides an absolute value for the soil sampled. It is useful in determining areas of magnetically enhanced soils caused by burning and intense occupation and can provide useful extra data in interpreting broad zones of land-use.

If time and money allows, using multiple techniques can create an even more nuanced appraisal of the surviving archaeological deposits. For example, stone buildings may show clearly on a GPR survey whereas pits and ditches may not appear at all but be obvious in a magnetometry survey.

The weakness of these techniques is that the interpretation of the results often relies on analogy with other known sites, and the techniques cannot provide secure dates. Using the results, however, enables archaeologists to accurately place their excavation trenches to answer specific questions whilst minimising the destruction of the archaeological record.

Deadliest superbugs are not the most toxic, new study shows

Staphylococcus aureus has confused researchers about how superbugs cause deadly infections. Janice Haney Carr/wikimedia

Infamous bacteria such as MRSA are considered “superbugs” because not only can they kill us using a wide range of virulence mechanisms, but they can also resist the effects of antibiotics. However, some superbugs reside on the skin and in the noses of a huge proportion of the human population causing only negligible problems for the majority.

Exactly why certain bacteria cause more severe infections than others is unclear. But for decades we have believed that the more toxins a bacteria produces, the worse infections it causes.

However, our latest study shows that, in the case of the bacterium Staphylococcus aureus (the SA in MRSA but also known as “golden staph”), quite the opposite is true.

The role of toxins

It is vitally important that we understand the link between superbugs and infections in detail. While infections due to S. aureus residing in the nose and skin can be mild and superficial, they can be life-threatening if they get in the bloodstream. Blood is normally a sterile environment, but bacteria can occasionally enter it during surgery or complications due to infections like pneumonia or other underlying health conditions such as diabetes. This serious condition, called bacteraemia, has mortality rates as high as 40%.

To try to understand this difference in severity, we focused on the ability of these bacteria to secrete toxins: proteins that physically destroy the membrane of human cells. The effect of bacteria-producing toxins on blood cells can be seen in the figure below. On the left we have highly toxic bacteria growing and a halo of broken-down blood cells can be seen, whereas on the right non-toxic bacteria are growing and the blood cells remain intact.

High and low toxic MRSA growing on the surface of horse-blood agar plates. Author provided

Given the destructive nature of bacterial toxins, we have for decades believed that the more toxic a bacteria is, the worse the severity of infection it can cause. To study this we examined two large collections of isolated S. aureus bacteria. One was from a patient before and after they developed bacteraemia. The second was from a wide range of patients, some isolated from their noses and some from their bloodstream after they developed bacteraemia.

Surprisingly, we found that in both cases, the bacteria from the bloodstream, which cause the most severe disease, were the least toxic. We also discovered that the fitness of the bacteria is key to this effect. Secreting toxins expends high levels of energy by the bacteria. And the bloodstream, where the majority of the human immune system exists primed and ready to respond to invasion, is a highly stressful environment for it.

We therefore believe that the energy required to produce toxins is too high for the bacteria to be able to also adapt to the high-stress environment of the bloodstream. This is why the less toxic bacteria get in there, causing the most severe of infections.

Challenging the dogma

This leaves us with the question of why we have for decades believed toxins to be so critical for bacteria to cause disease, to the extent that they have been the focus of numerous research labs across the globe and one of the major protein targets for vaccination programmes. Unfortunately, it’s a question to which there is no simple answer.

Toxins are important to many aspect of S. aureus’ life style. They kill off competitor bacteria, they release nutrients from human cells, they dampen down the human immune system allowing the bacteria to reside happily on our bodies as part of our normal flora. When they cause minor infections toxins are responsible for producing lots of pus, which is a great material for transmitting from one person to another … after all, who can resist popping a pimple?

But as there is no way to mimic all the complex interactions that occur in the body for serious bacterial infections, we are reliant on animal models to try to understand them. For S. aureus these are typically small rodents who do not naturally succumb to this pathogen. As such 10-100 million bacterial cells need to be injected directly into the rodent’s bloodstream to get experimentally reproducible infections. Compare this to the small handful of bacteria required to cause such infection in humans (<100) and it is clear to see where misinterpretations of such research findings can occur.

At a superficial level, the implications of our research are somewhat depressing in that despite decades of research we still have much to learn about how bacteria such as MRSA cause life-threatening disease. However, identifying the limitations to our knowledge, rather than blindly pursuing hypothesis based on misleading animal experiments has got to be a better starting point for the future of infectious disease research.

The age of drones has arrived quicker than the laws that govern them

No drone-fly zone. Niall Carson/PA

Just because you may not have seen a drone overhead doesn’t mean it hasn’t seen you. And, as was demonstrated by the killing of two British jihadis in Syria recently, these unmanned aerial vehicles are increasingly deployed by the West as frontline weapons of war.

Drones are set to become a defining feature of this century. Thousands are already in operation in most developed countries worldwide – and that is likely to grow to hundreds of thousands as drones of different shapes and sizes are deployed by the media, emergency services, scientists, farmers, sports enthusiasts, hobbyists, photographers, the armed forces and government agencies.

Eventually commercial uses will dwarf all others. Amazon promises to deliver purchases within 30 minutes via delivery drones. Domino’s Pizza has staged hot pizza drone delivery. More than 20 industries are approved to fly commercial drones in the US alone, and developing countries are following suit.

The question is, is this boom in drones moving faster than the law? How to fit such a proliferation of drones into the current regulations? The answers will need to be written into national and international laws quickly in order to govern an increasingly busy airspace. Many existing laws may need to be tweaked, including those governing cyber-security, stalking, privacy and human rights legislation, insurance, contract and commercial law, even the laws of war.

There have after all been numerous suspect or dangerous uses of drones already. For example, illegal flights over seven nuclear plants across France, disruption to US forest fire-fighting, and seven near-misses at airports in the UK. In the US several landowners have shot them down, leading to court cases that pit claims of trespass and the right to privacy against criminal damage.

Piecemeal legal changes not enough

French legislators responded swiftly with a police order to the first balloon flights by the Montgolfier Brothers in 1784 by prohibiting all flights over Paris without prior authorisation. In the same way sovereign states ought to define precisely how and when they will permit drone flights over their territory. So far legal development to govern drone use has been very piecemeal; most countries have done nothing yet.

Again, it was France that was first to introduce dedicated legislation governing drones through a decree in 2012 bringing drones within its civil aviation regulations. Drones are allowed to fly between 50-150 metres from the ground and there are penalties up to five years in prison and fines of 75,000 euros for unlawful use of a drone.

Also in 2012, the US congress passed the Federal Aviation Authority (FAA) Modernisation and Reform Act which required the integration of civil drones into national airspace by the end of September 2015.

The Italian Civil Aviation Authority issued commercial drone regulations in April 2014. The law vaguely requires the operators to comply with data-protection laws and hold insurance. In the meantime, controversial Italian surveillance firm Hacking Team is already developing drones capable of delivering spyware to computers and smartphones, infecting them via Wi-Fi.

However, the UK has struggled with fitting drones into its legal framework as neither the Civil Aviation Act nor the Air Navigation Order provide a good fit. The Department for Transport recently announced plans to introduce fines of up to £2,500 for flying drones in built-up areas. Some clarity is provided by the CAA’s Unmanned Aircraft System Operations in UK Airspace Guidance, which requires drone pilots to maintain direct line of sight with drones and limits their altitude to a maximum 120 metres. Small drones must avoid and give way to manned aircraft at all times.

Delivery by drone is already a happening in Switzerland. Jean-Christophe Bott/EPA

Flying in the face of the law

The International Civil Aviation Organisation (ICAO) plans to introduce policies to regulate civilian drone flight by 2028 worldwide. The EU and US have signed a formal agreement to cooperate on integrating drones into civil air traffic management. But consensus is notoriously difficult in international regulation – it could take decades to achieve a global agreement.

The last international civil air treaty of note is the 1944 Chicago convention. This impressive treaty created the standards for the common use of airspace between nations. For example, that every nation has sovereignty over its airspace and that no aircraft operated by the state (such as military or police) will fly over other states without authorisation. It also required nations air regulations to be obeyed and required aircraft to be registered and display their registration marks.

For drones, however, it’s not clear what types and sizes of drones are required to be registered and display their nationality. There are drones the size of small birds or even coins that can fly across national borders in near-invisibility, upsetting these egalitarian rules. It’s vital these issues are comprehensively dealt with quickly in a new treaty, in the same spirit of egalitarianism as at Chicago in 1944.

Dronefare versus Lawfare

For many, drones are typified by their use for military operations in Afghanistan and Iraq. The US is reported to have up to 7,000 drones in Afghanistan, with the main source of funding for developing modern drone technology coming from the military.

Successive US governments’ policies of conducting drone assassinations will perhaps go down as one of the most egregious use of air power in human history, with thousands of lives lost in an amorphous conflict against vaguely-defined al-Qaeda and ISIS “affiliates”. The only legitimisation in most cases appears to be White House’s early morning bureaucratic meetings.

The American Civil Liberties Union has correctly addressed this, stating: “The targeted killing program itself is not just unlawful but dangerous … it is dangerous to characterise the entire planet as a battlefield.” A recent RAF strike was the first targeted UK drone attack on a British citizen. However, UK armed Reaper drones have accounted for up to a third of the 100 airstrikes) in Iraq alone as at January 2015.

Lethal drone technology is going to be available to nearly all countries in a very short time. The possibility that even a few dozen states might follow the path beaten by the US is really a scary proposition – as what goes around may fly around.

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The web has become a hall of mirrors, filled only with reflections of our data

The web should expand our horizons, but instead it's shrinking our view. uroburos

The “digital assistant” is proliferating, able to combine intelligent natural language processing, voice-operated control over a smartphone’s functions and access to web services. It can set calendar appointments, launch apps, and run requests. But if that sounds very clever – a computerised talking assistant, like HAL9000 from the film 2001: A Space Odyssey – it’s mostly just running search engine queries and processing the results.

Facebook has now joined Apple, Microsoft, Google and Amazon with the launch of its digital assistant M, part of its Messaging smartphone app. It’s special sauce is that M is powered not just by algorithms but by data serfs: human Facebook employees who are there to ensure that every request that it cannot parse is still fulfilled, and in doing so training M by example. That training works because every interaction with M is recorded – that’s the point, according to David Marcus, Facebook’s vice-president of messaging:

We start capturing all of your intent for the things you want to do. Intent often leads to buying something, or to a transaction, and that’s an opportunity for us to [make money] over time.

Facebook, through M, will capture and facilitate that “intent to buy” and take its cut directly from the subsequent purchase rather than as an ad middleman. It does this by leveraging messaging, which was turned into a separate app of its own so that Facebook could integrate PayPal-style peer-to-peer payments between users. This means Facebook has a log not only of your conversations but also your financial dealings. In an interview with Fortune magazine at the time, Facebook product manager, Steve Davies, said:

People talk about money all the time in Messenger but end up going somewhere else to do the transaction. With this, people can finish the conversation the same place started it.

In a somewhat creepy way, by reading your chats and knowing that you’re “talking about money all the time” – what you’re talking about buying – Facebook can build up a pretty compelling profile of interests and potential purchases. If M can capture our intent it will not be by tracking what sites we visit and targeting relevant ads, as per advert brokers such as Google and Doubleclick. Nor by targeting ads based on the links we share, as Twitter does. Instead it simply reads our messages.

‘Hello Dave. Would you like to go shopping?’ summer1978/MGM/SKP, CC BY-ND

Talking about money, money talks

M is built to carry out tasks such as booking flights or restaurants or making purchases from online stores, and rather than forcing the user to leave the app in order to visit a web store to complete a purchase, M will bring the store – more specifically, the transaction – to the app.

Suddenly the 64% of smartphone purchases that happen at websites and mobile transactions outside of Facebook, are brought into Facebook. With the opportunity to make suggestions through eavesdropping on conversations, in the not too distant future our talking intelligent assistant might say:

I’m sorry Dave, I heard you talking about buying this camera. I wouldn’t do if I were you Dave: I found a much better deal elsewhere. And I know you’ve been talking about having that tattoo removed. I can recommend someone – she has an offer on right now, and three of your friends have recommended her service. Shall I book you in?

Buying a book from a known supplier may be a low risk purchase, but other services require more discernment. What kind of research about cosmetic surgery has M investigated? Did those three friends use that service, or were they paid to recommend it? Perhaps you’d rather know the follow-up statistics than have a friend’s recommendation.

Still, because of its current position as the dominant social network, Facebook knows more about us, by name, history, social circle, political interests, than any other single internet service. And it’s for this reason that Facebook wants to ensure M is more accurate and versatile than the competition, and why it’s using humans to help the AI interpret interactions and learn. The better digital assistants like M appear to us, the more trust we have in them. Simple tasks performed well builds a willingness to use that service elsewhere – say, recommending financial services, or that cosmetic treatment, which stand to offer Facebook a cut of much more costly purchase.

No such thing as a free lunch

So for Facebook, that’s more users spending more of their time using its services and generating more cash. Where’s the benefit for us?

We’ve been trained to see such services as “free”, but as the saying goes, if you don’t pay for it, then it’s you that’s the product. We’ve seen repeatedly in our Meaningful Consent Project that it’s difficult to evaluate the cost to us when we don’t know what happens to our data.

People were once nervous about how much the state knew of them, with whom they associated and what they do, for fear that if their interests and actions were not aligned with those of the state they might find ourselves detained, disappeared, or disenfranchised. Yet we give exactly this information to corporations without hesitation, because we find ourselves amplified in the exchange: that for each book, film, record or hotel we like there are others who “like” it too.

The web holds a mirror up to us, reflecting back our precise interests and behaviour. Take search, for instance. In the physical world of libraries or bookshops we glance through materials from other topics and different ideas as we hunt down our own query. Indeed we are at our creative best when we absorb the rich variety in our peripheral vision. But online, a search engine shows us only things narrowly related to what we seek. Even the edges of a web page will be filled with targeted ads related to something known to interest us. This narrowing self-reflection has grown ubiquitous online: on social networks we see ourselves relative to our self-selected peers or idols. We create reflections.

The workings of Google, Doubleclick or Facebook reveal these to be two-way mirrors: we are observed through the mirror but see only our reflection, with no way to see the machines observing us. This “free” model is so seductive – it’s all about us – yet it leads us to become absorbed in our phones-as-mirrors rather than the harder challenge of engaging with the world and those around us.

It’s said not to look too closely at how a sausage is made for fear it may put you off. If we saw behind the mirror, would we be put off by the internet? At least most menus carry the choice of more than one dish; the rise of services like M suggests that, despite the apparent wonder of less effortful interactions, the internet menu we’re offered is shrinking.

Got a great relationship? You may want to thank your prehistoric grandmother

Is there an old lady behind every happy couple? Alan Turkus/wikimedia, CC BY-SA

I went to a very international wedding last weekend. The guests crossed continents to be there, spoke mutually incomprehensible languages and came from different traditions. However, they all shared a common understanding of the relationship between the bride and the groom. Monogamous pair-bonds are, after all, universal in human societies, despite being rare in other mammals. And we don’t exactly know why.

Before the wedding breakfast, I chatted with a relaxed couple who had left their kids with their grandparents for the day. This is not unusual; UK grandparents babysit on average 76 times a year – and we often take it for granted. But now a new study finally gives grandparents the credit they deserve by arguing that long-term relationships actually evolved thanks to grandmothers helping out with kids in prehistoric times.

The greatness of grandparents

The question of why humans form pair bonds – the biological term for the strong affinity that develops between partners (often a male-female pair but not always) – is in fact one of the biggest puzzles in evolutionary anthropology. Humans are apes, yet our closest living relatives – chimpanzees and bonobos – have no such long-term relationships between male-female pairs.

Hadzabe women can have lots of kids, perhaps thanks to their grandmothers. idobi/wikimedia, CC BY-SA

In the late 1990s, anthropologists put forward the “grandmother hypothesis” to explain why human females stop reproducing at a similar age to other great apes, but live markedly longer lives. Chimpanzees live into their 30s or 40s, but human females often live decades beyond their child-bearing years.

The grandmother hypothesis was based on observations of the Hazda people, in Tanzania. Hadza people live by hunting and gathering food, like our ancestors, although, they are of course modern people.

Older Hazda women dig up tubers to feed youngsters who aren’t strong enough to it themselves. The grandmother hypothesis suggests that this help allows daughters to have their next baby sooner than they would otherwise. Over time, grandmothers who lived longer and helped more had more grandchildren, who shared their genes for longer life and care of their grandchildren. Thus, these genes became increasingly common in the population and human lifespan increased.

The evolution of partnership

The new study, published in the Proceedings of the National Academy of Sciences, has used computer simulations to link this hypothesis to the evolution of pair-bonding in humans. The authors argue that long-term romantic relationships evolved due to a combination of people living longer and men remaining fertile longer than women. This situation led to a surplus of older men competing for younger, fertile women.

In fact, the study shows that the ratio of fertile males to fertile females in humans is twice as big as it is in chimpanzees, making humans very unusual mammals. This excess of males makes us more like birds. And birds are well-known for their pair-bonds.

Family life sure is easier with a grandma around. Wavebreakmedia, Shutterstock.

Where many males compete for relatively few females, a male who develops a strong bond with one female will have more surviving offspring than males who seek numerous partners. The authors suggest that this created increasing incentives for men to “guard” their mate against rival males.

While mate-guarding is not necessarily the same thing as pair-bonding, the authors argue that both involve a trade-off between paying attention to the current partner and seeking a new one. Of course, although the study concentrates on male strategy, females are not passive in this scenario – it takes two to bond.

So, to put the wedding celebrations into their evolutionary context, perhaps it was the caring grandparents who led to the special relationship that we celebrated. A toast to the bride and groom … and one to their parents.

How does the Lexus hoverboard actually work? A scientist explains

Riding on air Lexus

Marty McFly wouldn’t be surprised. Lexus recently announced it had fulfilled the dreams of Back to the Future Part II fans everywhere by building a working hoverboard. And just in time for the October 2015 date that Marty visits in the film to discover kids have ditched skateboards in favour of their flying counterparts.

The Lexus “Slide” hoverboard isn’t set to go on sale but a prototype was recently put through its paces by pro-skateboarder Ross Mcgouran at a custom-built skate park in Barcelona. Now Lexus has also revealed how the device actually works, involving a special track that enables the board to magnetically levitate above it, in a very similar way to maglev trains.

It’s an amusing coincidence that, while Back to the Future featured technology called a flux capacitor, the Slide relies on something called flux pinning, as well as a principle called the Meissner effect. And this all works because of something called superconduction.

A superconductor is a material cooled to a very low critical temperature that, when you run a current through it, experiences no electrical resistance (the material doesn’t push back against the current). When a material becomes a superconductor it pushes away any magnetic fields inside it. This is known as the Meissner effect.

The Slide hoverboard contains a series of metal alloy superconducting blocks cooled to -197°C by reservoirs of liquid nitrogen. The track below contains three magnets that induce a current in the blocks, causing the Meissner effect to take hold and expel the magnetic field back towards the track in a mirror image.

These mirroring magnetic forces repel each other and so the board is lifted above the track. Even if someone stands on the board, the magnetic forces are strong enough to keep it levitating because the lack of electrical resistance in the superconductor means the magnetic field can adjust to deal with external pressure.

But another scientific phenomenon makes the hoverboard even more stable. When the cooling process is switched on and the blocks in the board become supercondutors, they effectively trap the lines of the magnetic field from the track. This causes the blocks to be pinned at a fixed height above the track, a process known as flux pinning, which provides much more stable levitation. Flux pinning ensures the hoverboard doesn’t deviate either horizontally or vertically from the track.

As a proof of concept, the Slide shows that constructing a hoverboard with stable levitation is entirely possible. Sadly, before we get too excited, the technology looks unlikely to hit the market in the near future for several reasons. The current board weighs 11.5kg, including the superconducting material and the liquid nitrogen on board, making it rather cumbersome to carry. The liquid nitrogen also requires a top-up roughly every 10 minutes to ensure that the superconducting material remains at optimal temperature.

On top of that, the board currently only works at one custom-built skate park. Lexus hasn’t disclosed the cost for this proof of concept, but it is safe to presume that superconducting blocks, supplies of liquid nitrogen and a custom-built park awash with permanent magnets could not have been cheap.

Despite these limitations – and as Lexus points out – nothing is impossible. It is entirely plausible to imagine similar parks and guide-ways being constructed as part of future smart cities. Perhaps the hoverboard could even offer a greener travel alternative within the city as well as a leisure activity. In years to come, we could well find ourselves topping up our boards with liquid nitrogen at city-wide charging points, just as we fill up our cars today.