Facebook Mentions App Finally Reaches Android

Facebook Mentions App Finally Reaches AndroidThe Facebook Mentions app, which was launched for iOS users back in 2014, has finally made it to Android. The app lets public figures with verified profiles broadcast live videos, interact with followers, track trending stories, and more. The app also lets public figures post public updates without spamming their friends and family members. They can also post Twitter or Instagram updates from within the app as well.

The Facebook Mentions app is now available to download from Google Play. It weighs 87MB and runs on Android 4.1 Jelly Bean and later OS verisons.

In September last year, Facebook updated its Mentions app, making it available for all public figures with verified profiles. The app was previously limited to select influencers only. In August, the app got the ability to broadcast live stream videos to allow actors, musicians, and other celebrities a new way to connect with their fans.


Notably, Facebook Mentions is another product from the company’s Creative Labs, which claims the app “makes it easy for public figures to talk with their fans and each other on the go.” The first Facebook Creative Labs product was the news reader, the Paper app.

Last month Facebook shut down its Creative Labs division, which made apps like Slingshot, Rooms, and Riff. The company besides curtailing the two-year old initiative has also removed the three apps fromGoogle Play and the App Store. According to Facebook, most of the features from Slingshot, Rooms, and Riff were already been integrated in Facebook app and Messenger. The Menlo Park, California-based company adds that the Slingshot and Riff app will continue to work for those who already have downloaded it. The company says that no one has been laid off after the division’s shut down.


Why the sun is setting on the Boeing 747

Why the sun is setting on the Boeing 747
Photo Credit: pixabay
Total Views
It’s difficult to imagine now, in the age of mass global travel, that building an aeroplane to carry hundreds of people at a time was once seen as a huge risk. But as the world’s first wide-body airliner, the Boeing 747 went on to change not only aviation but the entire tourism industry. Its economic design did much to move international travel within reach of middle-class holiday goers rather than just the privileged few.

However, the venerable Boeing 747 may be nearing the end of its production life – its manufacturing rate is to be halved to six a year. A shift towards newer and more efficient aircraft that can land at smaller (and so more) airports and a tendency to use former passenger planes for freight has reduced the remaining 747 order book to just 20, after building more than 1,500 since 1969.

Boeing’s decision to develop a new, giant airliner bigger than those of its competitors in the mid-1960s was a very bold move. It was a huge commercial risk that required borrowing some $2bn from a banking consortium, the largest amount of money ever borrowed by any corporation at that time. The gamble also involved buying a 780-acre site near Seattle to build a totally new manufacturing site, and promising to deliver its first orders in a shorter time than any normal projection to develop such a large aircraft.


But more than this, the company was throwing its resources into creating the world’s largest, widest, and (bar the much smaller Concorde) most technically advanced airliner, and doing so in a very complex market. Boeing’s competitors were also developing slightly smaller wide-body aircraft – defined as having two aisles or a cabin wider than 200 inches – that launched within two years of the 747’s 1969 debut.

But also, much of the world expected the future of air transport to be supersonic. Even Boeing hedged its bets somewhat by deliberately designing the 747 to be adapted as a freighter, in case supersonic passenger travel became the norm.

Compared to the competing McDonnell Douglas DC10 and Lockheed L1011 Tristar, the 747 was bigger and more expensive, carrying four instead of three engines (the most expensive components). But the fourth engine gave the plane a significant safety advantage in that it would retain much greater propulsion power if one of the engines failed. These engines – the Pratt and Whitney JT9D and the similarly sized Rolls Royce RB211 – also provided much greater power and better fuel economy than was previously available.

Two engines too many

The nose of the Boeing 747.
The nose of the Boeing 747.

Today, the industry has moved towards twin-engine aeroplanes such as the Boeing 777 and the Airbus A330, with three-engine aeroplanes being relatively unpopular because of the high labour costs of working on an engine bedded into the aeroplane fin. The four-engine 747 retained a clear place in the market because twin-engine planes must stay within a certain distance from an airport in case of engine failure. This allowed the 747 to achieve shorter journey times on the longest routes because it can use more direct flight paths.

However, improving engine reliability means authorities have slowly increased the distance a twin-engine airliner can fly from a runway, gradually reducing the advantage of having four engines. And of course, those newer, more reliable engines have also been bigger and more efficient.

Of course, the slowdown in 747 production doesn’t mean the original jumbo jet will disappear from our skies just yet. The latest models are much longer, bigger and operate with more modern engines and instruments than the earlier 747-100s (no longer do the crew have to take sextant readings through the cockpit roof), and the newer aircraft are likely to stay in service for at least another 20 years.

The size and flexibility of the design also mean the 747 provides some very specialist functions. For example, a joint US/German project has built a giant infrared space telescopeinto one. The US Air Force has installed a chemical laser into another as part of its Star Wars programme, and has successfully used it in tests to shoot down ballistic missiles.

However, the 747 has probably been improved as much as it can be. The four-engine wide-body aircraft may not be dead yet, but the 747’s nearest competitor the Airbus A380 has also suffered from the shift to smaller and more flexible aircraft and took no new orders last year. Boeing itself has moved on to other models, most recently the lightweight 787.

Still, the original jumbo jet will always be the aircraft that made Boeing into the global leader it is today, helping bring long-distance air travel to many of us who previously could never have dreamed of it.


Did the Vikings use crystal ‘sunstones’ to discover America?

Did the Vikings use crystal ‘sunstones’ to discover America?Photo Credit: Wikimedia Commons
Total Views
Ancient records tell us that the intrepid Viking seafarers who discovered Iceland, Greenland and eventually North America navigated using landmarks, birds and whales, and little else. There’s little doubt that Viking sailors would also have used the positions of stars at night and the sun during the daytime, and archaeologists have discovered what appears to be a kind of Viking navigational sundial. But without magnetic compasses, like all ancient sailors they would have struggled to find their way once the clouds came over.

However, there are also several reports in Nordic sagas and other sources of a sólarsteinn “sunstone”. The literature doesn’t say what this was used for but it has sparked decades of research examining if this might be a reference to a more intriguing form of navigational tool.

The idea is that the Vikings may have used the interaction of sunlight with particular types of crystal to create a navigational aid that may even have worked in overcast conditions. This would mean the Vikings had discovered the basic principles of measuring polarised light centuries before they were explained scientifically and which are today used to identify and measure different chemicals. Scientists are now getting closer to establishing if this form of navigation would have been possible, or if it is just a fanciful theory.

Scattering and polarisation

To understand how this might have worked, we need to understand some things about the way light, and particularly sunlight, can be affected. Light coming from the sun is scattered and polarised by the atmosphere. This occurs when light is absorbed and re-emitted with the same energy by air molecules and by different amounts depending on the light’s wavelength. The blue end of the light spectrum is scattered more than the red, as explained in theory developed by the British physicist Lord Rayleigh in the 19th century. Scattering by particles in the atmosphere explains why the sky appears blue.

More importantly, scattered light waves are also polarised to a certain extent. That means they vibrate in one plane rather than in all directions at once. The amount of polarisation a beam of sunlight undergoes depends on its angle to the viewer and whether the light has been further scattered by cloud and other particles that cause depolarisation.

Around the coastline of Norway and Iceland are found crystalline chunks of calcium carbonate known as calcite or Iceland spar. When polarised sunlight enters a calcite crystal, something very interesting happens. Calcite is strongly birefringent, meaning that it splits light passing through it into two separate waves that are bent or refracted in different directions and with different intensities, although the total intensity will be constant.

This means that objects viewed through a calcite crystal appear in double. More importantly for our purposes, the different intensities of the two light waves depends on how the original light is polarised and the position and orientation of the crystal compared to the light source.

Crystal clear double vision. Author provided
Crystal clear double vision. Author provided

Author provided

Tourmaline and cordierite are crystals with similar properties, except instead of splitting light like calcite they are strongly dichroic. This means they absorb one component of polarisation more strongly than the other. Again, the dichroic properties depend on how the original light is polarised and the position and orientation of the crystal compared to the light source.

So, in theory at least, examining how sunlight passes through one of these crystals – and appropriately calibrated – could be used as a guide for sailors to estimate the position of the sun. This could then allow them to determine the direction of geographic north – even without understanding the scientific principles behind these phenomena.

If we make the huge assumption that the Vikings had these sunstone crystals on board their ships and, more importantly, knew what they were doing with them, the question this is whether the difference in the light would be detectable to their eyes? And would it be detectable with enough accuracy (after errors because of imperfections in the crystals and depolarisation), to be used as a navigation aid even in overcast conditions.

Testing the theory

The latest in an impressive roster of publications on the subject recently appeared in Royal Society Open Science, seeking to address this precise question. Gabor Horvath and his colleagues looked at whether the optical signals from these three types of crystal would be strong enough to be detected and with enough accuracy to predict the position of the sun under a cloudy sky.

To do this, they simulated the conditions, including the position of the sun, of a Viking voyage between Norway, southern Greenland and Newfoundland. They found that in clear skies, where the degree of polarisation was high, all three crystals did show sufficient signal and good accuracy. In light cloudy conditions where the degree of polarisation was somewhat reduced but still relatively high, cordierite and tourmaline functioned better than calcite.

Only very pure calcite (with optical impurities removed) performed to a similar level as the other two crystals. If sunlight polarisation was very low, calcite appeared to give the best results in predicting the sun’s position through clouds. And in thicker cloudy conditions or fog, the errors of measurement became too high for all three crystals.

Horvath’s team are now looking at the further errors involved in predicting the position of geographical north using this information. If the method does not work under cloudy conditions when using the kind of imperfect crystals the Vikings would likely have possessed, the whole theory is probably wrong. And on clear days it would have been easier just to use calibrated sundials.

But if the researchers establish that sunstones could have accurately been used to determine the direction of geographic north, then the idea looks feasible. Then all that will remain to finally prove this fascinating theory will be to find a Viking ship with a calibrated sunstone in it. That, however, may take some time.


Disease may wipe out world’s bananas – but here’s how we might just save them

Disease may wipe out world’s bananas – but here’s how we might just save themPhoto Credit: pixabay
Total Views
Catastrophe is looming for the banana industry. A new strain has emerged of a soil-borne fungus known as “Panama disease” which can wipe out entire plantations – and it is rapidly spreading around the world. Farmers in Australia, Latin America and across Asiaand Africa all fear the worst.

The fungus is almost impossible to stop or eradicate. It moves through soil, so contamination can be as simple as infected dirt travelling from one farm to another on the sole of a shoe, or as complex as soil particles blowing on the wind across long distances – even across oceans, in theory.

Faced with huge losses to a global industry, many have called for a new strain of disease-resistant “superbanana”. However, this would be just another temporary fix. After all, the world’s most popular banana, the Cavendish, was itself the wonder fruit of its day, being introduced in the 1950s after an earlier strain of Panama disease destroyed its predecessor.

The fungi simply adapted and fought back, though, until the Cavendish also became susceptible. Panama and other diseases will continue to do so until we seriously reform how we grow and market bananas.

The banana industry is its own worst enemy. The huge farms where most exported bananas are grown are ideal for pests. These plantations are monocultures, which means they grow only bananas and nothing else. With very few shifts between crops over the years, and lots of tropical sunshine, there is an abundant and year-round supply of food for pests without any breaks, in time or space, to disrupt the supply and lower the disease pressure.

Banana producers spend a third of their income on controlling these pests, according to a study I published in 2013. Chemicals to control microscopic but deadly worms are applied several times a year. Herbicides that control weeds are applied up to eight times a year, while bananas may be sprayed with fungicides from a plane more than 50 times per year in order to control Black Sigatoka, an airborne fungus.

And those bags that are wrapped around each individual banana bunch? They’re lined with insecticides to serve as both a physical and chemical barrier to insects feeding on and damaging the skins.

All of this amounts to approximately one litre of active ingredients for every 18.6 kg box of bananas that is exported to consumers in the global north. It’s a huge, long-running problem for the industry and the new strain of Panama disease may just be the nail in its coffin.

Or maybe this is the wake-up call the export banana industry so desperately needs.

Searching for the superbanana

Given the way the fungus spreads, containment and quarantine are hardly long-term solutions. Some experts, especially those entrenched in the business of growing export bananas, argue that we need to breed or genetically modify a new type of banana that is resistant to the latest strain of Panama disease.

But this is harder than it sounds. Modern bananas – the tasty yellow ones – don’t exist in nature; they were bred into existence around 10,000 years ago. They reproduce asexually, which means they don’t have seeds and every banana is a genetic clone of the previous generation.

This lack of genetic variation makes breeding a new banana particularly challenging. If one Cavendish is susceptible to a disease, all others will be too. When all bananas are clones, how do you create the genetic variation from which traits for better disease resistance can be identified and nurtured?

A new banana would also have to be tasty, durable enough to withstand long voyages without bruising, and bright yellow. Looks really do trump pest-resistance. A new type of banana introduced during a previous Panama disease panic back in the 1920s was rejected by consumers for going black on the outside, even when it was ripe and sweet inside.

Saving the banana

Today, banana growers are in a fight for survival, continuously applying newly-formulated fungicides in an effort to keep ahead of the diseases. But they are acutely aware that they are losing ground. While breeding a new banana staves off the current problem, history has already shown that this doesn’t get to the root of the problem, which is the design of the production system.

We need to ditch the massive farms. Around the world, millions of small-scale farmers already grow bananas in a more organic and sustainable way. Alongside bananas are cacao, avocado, mango, corn, orange, lemon and more. A mix of crops creates more stable production systems which rely on fewer, if any, pesticides and generates diverse income sources, handing local people greater food sovereignty. Farms where bananas are mixed in with other crops are also more resilient to climate change which is likely to hit banana-producing regions – developing countries – harder than most.

Yes, this would mean fewer bananas are grown. Sustainable agriculture simply can’t keep up with the megafarms. But if we learned to ignore the odd blemished or undersized banana, then the actual amount sent to market need not drop at all.

The farmers themselves should be okay as they’ll make up their income by producing different crops. Breaking the dominance of the banana multinationals should also distribute wealth among more farmers and empower the regions where they’re grown. As a consumer, ask yourself this: isn’t that a far better way to spend your money?