How to stop fertiliser being washed away by the rain

Spreading growth

IN MEDIEVAL England peasants were permitted to graze their sheep on the lands of the nobility. There were no restrictions on how much their livestock could feed, but there was one ironclad rule: the peasants were not allowed to collect their animals’ droppings. Though the English nobles who came up with such regulations could not have known that the excrement was rich in nitrogen and vital for plant growth, they clearly knew that lands denied faeces were less productive. Today most farmers rely on synthetic fertilisers to do the nitrogen-enhancing job once reserved for dung. Urea, a compound of nitrogen, hydrogen, carbon and oxygen, can be made cheaply by mixing ammonia and carbon dioxide together at high pressure. The result is turned into pellets that can be scattered easily over fields.

Unfortunately, when such pellets are exposed to heavy rain, the urea they contain is quickly and wastefully washed away. A method of keeping it in place would thus be welcome. And Nilwala Kottegoda of the Sri Lanka Institute of Nanotechnology thinks she has one. As she and her team report in <em…Continue reading
Source: Economist

What causes nodding syndrome

NODDING syndrome is a form of epilepsy that strikes children, mostly between the ages of five and 15. Despite the innocuous name, it is debilitating. It robs its victims of their mental capacity, stunts their growth and causes both the characteristic “nodding-off” motion which gives its name and more serious seizures, often when a child is being fed. The exact death rate is unknown, but it is high.

The syndrome is also something of a medical mystery. The first cases were identified in Tanzania in the 1960s. Now it has spread to parts of Uganda and South Sudan. No one knows how many people are affected, but it is thousands, at least. Nor has anyone been sure what causes the disease. But Tory Johnson, of America’s National Institutes of Health, and her colleagues have a theory. As they describe in a paper just published in Science Translational Medicine, they suspect that nodding syndrome is an “autoimmune” disease caused by sufferers’ attempts to fight off infection by a parasitic worm.

The worm in question is Onchoerca volvulus, a tiny nematode spread by the bites of black flies that is best known for…Continue reading
Source: Economist

The cause of nodding syndrome

NODDING syndrome is a form of epilepsy that strikes children, mostly between the ages of five and 15. Despite the innocuous name, it is debilitating. It robs its victims of their mental capacity, stunts their growth and causes both the characteristic “nodding-off” motion which gives its name and more serious seizures, often when a child is being fed. The exact death rate is unknown, but it is high.

The syndrome is also something of a medical mystery. The first cases were identified in Tanzania in the 1960s. Now it has spread to parts of Uganda and South Sudan. No one knows how many people are affected, but it is thousands, at least. Nor has anyone been sure what causes the disease. But Tory Johnson, of America’s National Institutes of Health, and her colleagues have a theory. As they describe in a paper just published in Science Translational Medicine, they suspect that nodding syndrome is an “autoimmune” disease caused by sufferers’ attempts to fight off infection by a parasitic worm.

The worm in question is Onchocerca volvulus, a tiny nematode spread by the bites of…Continue reading
Source: Economist

Cloning time

Twenty years ago, Dolly the sheep became the first adult…Continue reading
Source: Economist

The world’s deepest ocean trenches are packed with pollution

NOT far off the coast of Guam lies the deepest point on Earth’s surface, the Mariana trench. Its floor is 10,994 metres below sea level. If Mount Everest were flipped upside down into it, there would still be more than 2km of clear water between the mountain’s base and the top of the ocean. Such isolation has led many to assume that it and similar seabed trenches will be among the few remaining pristine places on the planet. However, a study led by Alan Jamieson of Newcastle University in England, has shown that nothing could be further from the truth. As Dr Jamieson and his colleagues report this week in Nature Ecology and Evolution, trenches actually are loaded with pollutants.

Despite the cold, the darkness and the high pressure, ocean trenches are home to ecosystems similar in many ways to those found on other parts of the planet. In one important respect, though, they are different. This is where the energy that powers them comes from. In most ecosystems, sunlight fuels the growth of plants which are then consumed by animals. In a few shallower parts of the ocean, hydrothermal vents provide energy-rich chemicals that form the basis…Continue reading
Source: Economist

Nasty chemicals abound in what was thought an untouched environment

A messenger from the deep

NOT far off the coast of Guam lies the deepest point on Earth’s surface, the Mariana trench. Its floor is 10,994 metres below sea level. If Mount Everest were flipped upside down into it, there would still be more than 2km of clear water between the mountain’s base and the top of the ocean. Such isolation has led many to assume that it and similar seabed trenches will be among the few remaining pristine places on the planet. However, a study led by Alan Jamieson of Newcastle University, in England, has shown that nothing could be further from the truth. As Dr Jamieson and his colleagues report this week in Nature Ecology and Evolution, trenches are actually loaded with pollutants.

Despite the cold, the darkness and the high pressure, ocean trenches are home to ecosystems similar in many ways to those found on other parts of the planet. In one important respect, though, they are different. This is the source of the energy that powers them. In most ecosystems, sunlight fuels the growth of plants, which are then consumed by animals. In a few shallower parts of the…Continue reading
Source: Economist

Game of drones

Robotic insects could help pollinate plants if bee numbers continue to…Continue reading
Source: Economist

How to determine a protein’s shape

ABOUT 120,000 types of protein molecule have yielded up their structures to science. That sounds a lot, but it isn’t. The techniques, such as X-ray crystallography and nuclear-magnetic resonance (NMR), which are used to elucidate such structures do not work on all proteins. Some types are hard to produce or purify in the volumes required. Others do not seem to crystallise at all—a prerequisite for probing them with X-rays. As a consequence, those structures that have been determined include representatives of less than a third of the 16,000 known protein families. Researchers can build reasonable computer models for around another third, because the structures of these resemble ones already known. For the remainder, however, there is nothing to go on. 

In addition to this lack of information about protein families, there is a lack of information about those from the species of most interest to researchers: Homo sapiens. Only a quarter of known protein structures are human. A majority of the rest come from bacteria. This paucity is a problem, for in proteins form and function are intimately related. A protein is a chain of…Continue reading
Source: Economist

Plans for artificial pollinators are afoot

IT IS, in one way, the ultimate drone. In another, though, it is the antithesis of what a drone should be. Drones are supposed to laze around in the hive while their sisters collect nectar and pollinate flowers. But pollination is this drone’s very reason for existing.

The drone in question is the brainchild of Eijiro Miyako, of the National Institute of Advanced Industrial Science and Technology, in Tsukuba, Japan. It is the first attempt by an engineer to deal with what many perceive as an impending agricultural crisis. Pollinating insects in general, and bees in particular, are falling in numbers. The reasons why are obscure. But some fear certain crops will become scarcer and more expensive as a result. Attempts to boost the number of natural pollinators have so far failed. Perhaps, thinks Dr Miyako, it is time to build some artificial ones instead.

His pollinator-bot does not, it must be said, look much like a bee. It is a modified version of a commercially available robot quadcopter, 42mm across. (By comparison, a honeybee worker is about 15mm long.) But the modifications mean it can, indeed, pollinate flowers. Specifically—and…Continue reading
Source: Economist

Hans Rosling, statistician and sword-swallower, has died

STATISTICS has not, traditionally, been an exciting word. Its most common prefix is the word “dry”. Ask people what they think of statistics, or try to use some in an argument, and you will often get the quote attributed to Benjamin Disraeli that lists them alongside lies and damned lies. That is a shame: tables of figures may look dull, but they are a better guide to what is happening in the world than anything on television or in the press.

Hans Rosling had no time for the idea that statistics were boring. Armed with everything from a few Lego bricks and a pocketful of draughts pieces to snazzy, specially made computer graphics, he had a talent for using numbers to tell exciting stories. Not just exciting, but optimistic, too, for the tales those numbers told were of a world which, despite the headlines, was rapidly becoming a better place.

He knew what he was talking about. Besides being a statistician, he was also a doctor with experience in some of the world’s poorest corners. He did his PhD in Africa, studying a disease called konzo that strikes people whose diets include a lot of semi-processed cassava, which contains high levels…Continue reading
Source: Economist