From hype to hyperloop

Vacuum-based hyperloop technology could transport passengers between cities cheaply at more than half the speed of sound – or so its proponents claim. Jon Cartwright takes a closer look

In the late summer of 1864, anyone wanting to travel along the east side of Crystal Palace Park in London could buy a train ticket for sixpence – but this was no ordinary railway. Designed by the British engineer Thomas Webster Rammell, the Crystal Palace pneumatic railway consisted of a carriage that fitted snugly inside a tunnel, such that when a huge fan was turned on, the carriage was sucked from one end of the tunnel to the other. Average speeds of around 40 km/h meant that passengers could make the 550 metre trip in a little under a minute – twice as fast as the carriage’s horse-drawn competitors.

Rammell’s pneumatic railway was experimental, and it only ran for two months. A century and a half later, however, the idea of getting from A to B inside depressurized passages is back, thanks to another entrepreneurial visionary: Elon Musk, the South-African born, Canadian-American multibillionaire behind Tesla electric cars and SpaceX rockets. In 2013 Musk published a white paper outlining the concept of a hyperloop: an evacuated steel tube through which passenger “pods” travel cheaply and efficiently over continental distances. Thanks to the minimal air resistance, Musk claimed, the pods could be accelerated to speeds of up to 760 km/h.

The hyperloop sounds almost too good to be true, and many critics have said as much, branding Musk’s idea impractical, unsafe and – for various political and economic reasons – unrealizable. But in the four years since Musk’s white paper, at least three major start-ups have been created, and dozens of academics and industry professionals have climbed on board – figuratively if not yet literally. Their hope is to revolutionize public transport and, in so doing, restructure society for the better. […]

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Fire impacts climate more than land use

Fire-induced changes to ecosystems have a greater impact on the climate than land-use and land-cover change, according to researchers in China and the US.

The study is the first to quantify the global impact of fire by its effect on ecosystems, rather than by its emission of trace gases and aerosols. Fire-induced changes to ecosystems boosted surface air temperatures by 0.18°C above the 20th century average, the researchers found.

“Our work is critical to improve our understanding of fire’s role in the Earth system as well as the potential broader impact of fire management, and to provide a direct reason supporting why Earth system models should include fire modelling for global research agendas,” said Fang Li of the Institute of Atmospheric Physics at the Chinese Academy of Sciences in Beijing. […]

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Namibian wetlands replenished by rainfall

The seasonal wetlands of north-central Namibia are likely to be replenished by surface water that is sourced from local rainfall, a study by researchers in Japan and Namibia has shown.

Measurements of isotopic ratios in water samples suggest that to conserve surface and subsurface waters, shallow groundwater should not be pumped intensively.

“We have to develop [a] new agricultural system to overcome climate change as quickly as possible,” said Morio Iijima of Kindai University, Japan. “It should be not only an environmentally-friendly system to preserve water balance in this semi-arid region, but also a beneficial one for small-scale farmers.” […]

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Slowly oxidizing peat releases as much carbon as burning in Southeast Asia

Peat oxidation in the west of insular Southeast Asia has resulted in the release of 2.5 gigatonnes of carbon since 1990, according to researchers in Singapore, the Netherlands and the UK.

The estimates, based on field emission studies carried out over two decades, also show that the latest year studied, 2015, saw levels of carbon emissions from peat amounting to two-thirds of that from the burning of fossil fuels, the production of cement, and gas flaring in Malaysia and Indonesia.

Although Jukka Miettinen of the National University of Singaporebelieves the estimates are “not surprising”, they should draw attention to the contribution of peatland oxidation to global greenhouse-gas emissions. […]

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The Higgs bang

Did the mass-giving particle make the universe too, asks Jon Cartwright

THEY say it started with a bang, but in truth it misfired. The universe began as
a hot speck of energy and, for an instant, remained just that. Then it blew up: from this initial seed, trillions upon trillions of times smaller than an atom, everything suddenly ballooned into the gargantuan proportions of a Tic Tac. In a mere fraction of a second, the universe expanded by nearly as many orders of magnitude as it would in the following 13.8 billion years.

Believe it or not, this burst of cosmological inflation, followed by a slower, tamer expansion, is the most sensible way to explain how the universe looks today. But there’s something missing: what did the inflating?

The answer could be everywhere, and right under our noses. When a long-sought particle finally appeared a few years back, it seemed to close a chapter in physics without giving any clue about what happens next. Read between the lines, though, as some theorists recently have, and you see that the famous Higgs boson – the particle that gives mass, or inertia, to all other particles – might have an explosive secret. “If the Higgs gives inertia to particles,” says Juan García-Bellido at the Autonomous University of Madrid, “can it give inertia to the entire universe?” […]

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Scientists chart peak orange

For the past three decades, scientists in the US have determined the onset of peak foliage colouration for central and eastern US forests. The results revealed mixed trends for when leaves turned orange, and could improve predictions for carbon dynamics in climate models.

Vegetation cycles play a big role in the world’s carbon fluxes: green leaves absorb carbon dioxide to produce carbohydrates for plant growth, whilst browning leaves mark the end of this process. The later the onset of colouration, and the longer the growing season, the greater the expected carbon uptake – and the less carbon left in the atmosphere. While a lot of studies have focused on the timing of new growth in spring, say Lingling Liu and Xiaoyang Zhang of South Dakota State University, US, fewer have focused on when leaves turn orange.

“Determining the long-term peak-colouration timing and its complexity greatly improves the calculation of the vegetation growing season length, which [in turn] facilitates more reliable measures of carbon dynamics in vegetation–climate interactions models,” said Liu. […]

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Anatomy changes assessed for proton therapy

Researchers in the Netherlands have developed a population-based statistical model that could improve proton treatment plans for lung cancer patients. The method assesses the daily anatomical variations of the thorax, and complements other methods that account for device uncertainty and respiratory motion (Radiother. Oncol. 123 99).

Proton therapy is similar to conventional radiotherapy in that it is used to destroy tumours, but in principle has a finite range that spares surrounding healthy tissue. Such precision, however, can be thwarted by a patient’s changing anatomy during a treatment plan. To avoid missing the tumour, radiotherapists will sometimes expand the target of radiation over the course of treatment, but studies have shown this method to be insufficient for proton therapy, as it can still end up delivering too little radiation to the tumour and too much radiation to healthy tissue, worsening side effects. The problem is more acute for lung cancer patients, as the contrast in tissue density in the thorax is much greater. […]

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Latin American oil palm mostly replaces pasture

Oil-palm plantations in Latin America are mostly replacing cattle pasture and other previously intervened lands rather than forests, a study by scientists in Puerto Rico has found.

The research – which also revealed that most exported oil palm stays within the region – suggests that Latin America is a “major opportunity” for the sustainable palm-oil sector, according to the scientists.

“The oil-palm industry has faced enormous scrutiny because of destructive practices in Asia,” said Paul Furumo of the University of Puerto Rico-Río Piedras. “Our study reveals a different narrative of oil-palm expansion in Latin America, one in which cattle pastures and other previously intervened lands are the most significant source of new plantings instead of forests.” […]

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First in vivo MPI of lung perfusion in rats

Researchers in the US have invented an imaging agent that allows magnetic particle imaging (MPI) of lung perfusion in rats. The test bodes well for the clinical use of MPI, which unlike other lung-imaging techniques delivers no ionizing radiation and only requires small amounts of the agent to be injected.

MPI is an emerging imaging technique that forms direct images from the location of superparamagnetic iron oxide nanoparticles (SPIOs) injected into the bloodstream. The images are high contrast because they rely on electronic rather than nuclear magnetization as in nuclear MRI; but unlike other high-contrast imaging techniques, such as PET, CT and X-rays, they require no ionizing radiation.

MPI scanners themselves are in the early stages of commercialization. Meanwhile, Steven Conolly and Xinyi Zhou of UC Berkeley and others have developed the first MPI agent for imaging a particular organ, the lungs. The agent is an aggregate of SPIOs and macroaggregated albumin (MAA), the latter of which has already been used in nuclear medicine studies of the lungs because it is several times thicker than a lung’s capillaries. “In those studies, radiotracers are incorporated into the MAA to produce an image,” says Zhou. “Hence, we came up the idea to incorporate SPIOs into the MAA to produce an MPI lung image.” […]

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