A way to predict sinkholes under spas near the Dead Sea

THE Dead Sea is, as its name implies, far too salty to be of use to fishermen or farmers. But its mineral-rich waters are valued by the owners of the spas that thrive along its shores in Israel, Jordan and the Palestinian territory of the West Bank. The spa industry, however, faces a threat from a plague of sinkholes that have struck in recent years. These have damaged roads and buildings at Ein Gedi beach, in Israel, and hit the Mineral Beach Spa in Mitzpe Shalem, an Israeli settlement in the West Bank, so hard that it is unusable.

Until now, it has been impossible to predict more than a few weeks in advance where a sinkhole will appear. But, as he reports in Geology, Meir Abelson of the Geological Survey of Israel thinks he can change that. Employing buried monitoring devices, he believes he can forecast where such holes will form several years before they actually do so.

Most of the more than 6,000 sinkholes that have struck the west coast of the Dead…

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Source:: The Economits – Science and technology

Big fish keep tropical forests healthy

FOR anglers nothing beats catching a big fish. Commercial fisherfolk also prefer to haul in big specimens. Unfortunately, in recent years, research has shown that selectively capturing the largest fish has worrying ecological consequences. In some species the large ones are the healthiest ones, and so the ones most likely to breed successfully. In others they are the oldest, and so the most experienced at eluding predators or securing resources, such as food and breeding sites. In tropical wetlands, such as the Pantanal and Amazon regions of Brazil, the largest fish are also vital in dispersing seeds—and thus maintaining and regenerating habitat.

Trees in these areas fruit most prolifically during the summer, when local rivers burst their banks and flood the land, making those fruit available to fish, which gladly gobble them up. Then, as the fish swim around the floodplain, they pass the seeds inside those fruit, which often remain intact, as part of their faeces. These…

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Source:: The Economits – Science and technology

The crabs who ate Christmas

Christmas Island — a tiny Australian territory in the Indian Ocean, about 500 miles south of Indonesia — was named by an English captain who happened to spot it on Dec. 25, 1643.

But the island boasts another festive source for its name: At the end of every year, a rare phenomenon sweeps over its natural green terrain, turning it bright red.

(WaterFrame / Alamy Stock Photo)

Alongside a plethora of exotic tropical creatures and about 2,000 humans, Christmas Island is home to a whopping 50 million bright red land crabs — called the Gecarcoidea natalis — that exist nowhere else in the world.

These large arthropods live out most of their days in shady coves within the island’s dense forests, but each year, they make one epic journey from the inner jungles to the coast. Because their larvae cannot survive outside water for the first few weeks after hatching, the terrestrial crabs must trek out to the ocean to breed and spawn. During this mass migration, the island’s streets, sidewalks, and beaches are blanketed in crimson claws.

“They swarm over the island, across roads, through homes and schools, under every foot, every tire, inside unattended shoes and covering every surface available,” Atlas Obscura reports.

(Kirsty Faulkner/Courtesy Christmas Island Tourism Association)

(Courtesy Christmas Island Tourism Association)

(Indo Arndt/Courtesy Christmas Island Tourism Association)

(Justin Gilligan/Courtesy Christmas Island Tourism Association)

The annual event begins with the start of the wet season, usually around October or November, with the male crabs journeying out to stake out a good spot and the female crabs following soon after. The entire pilgrimage can take up to 18 days and can often be a dangerous journey for the crabs, facing poisonous ants, racing cars, and swaths of concrete or wide-open fields where they can overheat and die of dehydration under the burning sun.

The locals …read more

Source:: The Week – Science

Game over for virtual reality?

LIKE the rest of the consumer-electronics industry, video-game makers would be lost without the traditional binge buying that happens between mid-November and the late December. This year’s gift-giving season will be as much a treat for makers of video-gaming gadgets as for their happy recipients. Prices of the headsets, sensors and controllers that let game-players explore the artificial world of virtual reality (VR) have been slashed to levels most families can now afford. Stockings could be bulging with VR headsets from Samsung, Dell, Sony, HTC, Oculus and others. For those willing to wait until early 2018, costs could fall still further—as a new, even cheaper generation of VR headsets hits the market.

Despite the merry ho, ho, ho, however, there is a distinct whiff of urgency in the air. Virtual reality has failed to live up to its hype, and mainstream consumers never really bought into the technology. Even ardent gaming fans have been slow to embrace VR. No-one can…

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Source:: The Economits – Science and technology

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