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Quantum physics: Teleportation for two

Nature - Wed, 02/25/2015 - 01:00

Quantum physics: Teleportation for two

Nature 518, 7540 (2015). doi:10.1038/518491a

Authors: Wolfgang Tittel

The 'no-cloning' theorem of quantum mechanics forbids the perfect copying of properties of photons or electrons. But quantum teleportation allows their flawless transfer — now even for two properties simultaneously. See Letter p.516

Categories: Literature

Molecular biology: RNA modification does a regulatory two-step

Nature - Wed, 02/25/2015 - 01:00

Molecular biology: RNA modification does a regulatory two-step

Nature 518, 7540 (2015). doi:10.1038/518492a

Authors: Dominik Theler & Frédéric H.-T. Allain

The m6A structural modification of RNA regulates gene expression. It has now been found to mediate an unusual control mechanism: by altering the structure of RNA, m6A allows a regulatory protein to bind to that RNA. See Letter p.560

Categories: Literature

Whole genomes redefine the mutational landscape of pancreatic cancer

Nature - Wed, 02/25/2015 - 01:00

Whole genomes redefine the mutational landscape of pancreatic cancer

Nature 518, 7540 (2015). doi:10.1038/nature14169

Authors: Nicola Waddell, Marina Pajic, Ann-Marie Patch, David K. Chang, Karin S. Kassahn, Peter Bailey, Amber L. Johns, David Miller, Katia Nones, Kelly Quek, Michael C. J. Quinn, Alan J. Robertson, Muhammad Z. H. Fadlullah, Tim J. C. Bruxner, Angelika N. Christ, Ivon Harliwong, Senel Idrisoglu, Suzanne Manning, Craig Nourse, Ehsan Nourbakhsh, Shivangi Wani, Peter J. Wilson, Emma Markham, Nicole Cloonan, Matthew J. Anderson, J. Lynn Fink, Oliver Holmes, Stephen H. Kazakoff, Conrad Leonard, Felicity Newell, Barsha Poudel, Sarah Song, Darrin Taylor, Nick Waddell, Scott Wood, Qinying Xu, Jianmin Wu, Mark Pinese, Mark J. Cowley, Hong C. Lee, Marc D. Jones, Adnan M. Nagrial, Jeremy Humphris, Lorraine A. Chantrill, Venessa Chin, Angela M. Steinmann, Amanda Mawson, Emily S. Humphrey, Emily K. Colvin, Angela Chou, Christopher J. Scarlett, Andreia V. Pinho, Marc Giry-Laterriere, Ilse Rooman, Jaswinder S. Samra, James G. Kench, Jessica A. Pettitt, Neil D. Merrett, Christopher Toon, Krishna Epari, Nam Q. Nguyen, Andrew Barbour, Nikolajs Zeps, Nigel B. Jamieson, Janet S. Graham, Simone P. Niclou, Rolf Bjerkvig, Robert Grützmann, Daniela Aust, Ralph H. Hruban, Anirban Maitra, Christine A. Iacobuzio-Donahue, Christopher L. Wolfgang, Richard A. Morgan, Rita T. Lawlor, Vincenzo Corbo, Claudio Bassi, Massimo Falconi, Giuseppe Zamboni, Giampaolo Tortora, Margaret A. Tempero, Anthony J. Gill, James R. Eshleman, Christian Pilarsky, Aldo Scarpa, Elizabeth A. Musgrove, John V. Pearson, Andrew V. Biankin & Sean M. Grimmond

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole-genome sequencing and copy number variation (CNV) analysis of 100 pancreatic ductal adenocarcinomas (PDACs). Chromosomal rearrangements leading to gene disruption were prevalent, affecting genes known to be important

Categories: Literature

An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30

Nature - Wed, 02/25/2015 - 01:00

An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30

Nature 518, 7540 (2015). doi:10.1038/nature14241

Authors: Xue-Bing Wu, Feige Wang, Xiaohui Fan, Weimin Yi, Wenwen Zuo, Fuyan Bian, Linhua Jiang, Ian D. McGreer, Ran Wang, Jinyi Yang, Qian Yang, David Thompson & Yuri Beletsky

So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (109). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 1010, which is consistent with the 1.3 × 1010 derived by assuming an Eddington-limited accretion rate.

Categories: Literature

Quantum teleportation of multiple degrees of freedom of a single photon

Nature - Wed, 02/25/2015 - 01:00

Quantum teleportation of multiple degrees of freedom of a single photon

Nature 518, 7540 (2015). doi:10.1038/nature14246

Authors: Xi-Lin Wang, Xin-Dong Cai, Zu-En Su, Ming-Cheng Chen, Dian Wu, Li Li, Nai-Le Liu, Chao-Yang Lu & Jian-Wei Pan

Quantum teleportation provides a ‘disembodied’ way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom—internal and external—and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin–orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

Categories: Literature

Dynamically reconfigurable complex emulsions via tunable interfacial tensions

Nature - Wed, 02/25/2015 - 01:00

Dynamically reconfigurable complex emulsions via tunable interfacial tensions

Nature 518, 7540 (2015). doi:10.1038/nature14168

Authors: Lauren D. Zarzar, Vishnu Sresht, Ellen M. Sletten, Julia A. Kalow, Daniel Blankschtein & Timothy M. Swager

Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including Janus droplets (that is, droplets with faces of differing chemistries) and multiple emulsions, are of increasing importance in pharmaceuticals and medical diagnostics, in the fabrication of microparticles and capsules for food, in chemical separations, in cosmetics, and in dynamic optics. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets’ physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes, to small-volume but more precise microfluidic methods. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have great utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with controllably reconfigurable morphologies and the potential to create a wide range of responsive materials.

Categories: Literature

Human-level control through deep reinforcement learning

Nature - Wed, 02/25/2015 - 01:00

Human-level control through deep reinforcement learning

Nature 518, 7540 (2015). doi:10.1038/nature14236

Authors: Volodymyr Mnih, Koray Kavukcuoglu, David Silver, Andrei A. Rusu, Joel Veness, Marc G. Bellemare, Alex Graves, Martin Riedmiller, Andreas K. Fidjeland, Georg Ostrovski, Stig Petersen, Charles Beattie, Amir Sadik, Ioannis Antonoglou, Helen King, Dharshan Kumaran, Daan Wierstra, Shane Legg & Demis Hassabis

The theory of reinforcement learning provides a normative account, deeply rooted in psychological and neuroscientific perspectives on animal behaviour, of how agents may optimize their control of an environment. To use reinforcement learning successfully in situations approaching real-world complexity, however, agents are confronted with a difficult task: they must derive efficient representations of the environment from high-dimensional sensory inputs, and use these to generalize past experience to new situations. Remarkably, humans and other animals seem to solve this problem through a harmonious combination of reinforcement learning and hierarchical sensory processing systems, the former evidenced by a wealth of neural data revealing notable parallels between the phasic signals emitted by dopaminergic neurons and temporal difference reinforcement learning algorithms. While reinforcement learning agents have achieved some successes in a variety of domains, their applicability has previously been limited to domains in which useful features can be handcrafted, or to domains with fully observed, low-dimensional state spaces. Here we use recent advances in training deep neural networks to develop a novel artificial agent, termed a deep Q-network, that can learn successful policies directly from high-dimensional sensory inputs using end-to-end reinforcement learning. We tested this agent on the challenging domain of classic Atari 2600 games. We demonstrate that the deep Q-network agent, receiving only the pixels and the game score as inputs, was able to surpass the performance of all previous algorithms and achieve a level comparable to that of a professional human games tester across a set of 49 games, using the same algorithm, network architecture and hyperparameters. This work bridges the divide between high-dimensional sensory inputs and actions, resulting in the first artificial agent that is capable of learning to excel at a diverse array of challenging tasks.

Categories: Literature

N6-methyladenosine-dependent RNA structural switches regulate RNA–protein interactions

Nature - Wed, 02/25/2015 - 01:00

N6-methyladenosine-dependent RNA structural switches regulate RNA–protein interactions

Nature 518, 7540 (2015). doi:10.1038/nature14234

Authors: Nian Liu, Qing Dai, Guanqun Zheng, Chuan He, Marc Parisien & Tao Pan

RNA-binding proteins control many aspects of cellular biology through binding single-stranded RNA binding motifs (RBMs). However, RBMs can be buried within their local RNA structures, thus inhibiting RNA–protein interactions. N6-methyladenosine (m6A), the most abundant and dynamic internal modification in eukaryotic messenger RNA, can be selectively recognized by the YTHDF2 protein to affect the stability of cytoplasmic mRNAs, but how m6A achieves its wide-ranging physiological role needs further exploration. Here we show in human cells that m6A controls the RNA-structure-dependent accessibility of RBMs to affect RNA–protein interactions for biological regulation; we term this mechanism ‘the m6A-switch’. We found that m6A alters the local structure in mRNA and long non-coding RNA (lncRNA) to facilitate binding of heterogeneous nuclear ribonucleoprotein C (HNRNPC), an abundant nuclear RNA-binding protein responsible for pre-mRNA processing. Combining photoactivatable-ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) and anti-m6A immunoprecipitation (MeRIP) approaches enabled us to identify 39,060 m6A-switches among HNRNPC-binding sites; and global m6A reduction decreased HNRNPC binding at 2,798 high-confidence m6A-switches. We determined that these m6A-switch-regulated HNRNPC-binding activities affect the abundance as well as alternative splicing of target mRNAs, demonstrating the regulatory role of m6A-switches on gene expression and RNA maturation. Our results illustrate how RNA-binding proteins gain regulated access to their RBMs through m6A-dependent RNA structural remodelling, and provide a new direction for investigating RNA-modification-coded cellular biology.

Categories: Literature

New Map Shows Background Noise Levels Across the United States

Yale Environment 360 - Tue, 02/24/2015 - 11:48

A new map by the U.S. National Park Service (NPS) shows America's quietest and noisiest places. The park service

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Background noise levels mapped background noise levels across the country on an average summer day using 1.5 million hours of acoustical data. The quietest areas of the country, such as Yellowstone National Park in Wyoming, are shown in deep blue on this map and are likely as quiet now as they were before European colonization, NPS researchers say. They are collecting the data as part of an effort to determine whether and how wild animals are affected by anthropogenic noise pollution. Owls and bats, for example, rely on hearing faint rustles from insects and rodents, and scientists think human-driven noise could be drowning out those subtle signals in many areas of the country.

Categories: Environmental News

When right beats might

Nature - Tue, 02/24/2015 - 01:00

When right beats might

Nature 518, 7540 (2015). doi:10.1038/518455a

The final act in a long-running Italian saga should bring tighter controls on unproven stem-cell therapies, both at home and abroad.

Categories: Literature

Focus on political Islamic groups to boost science

Nature - Tue, 02/24/2015 - 01:00

Focus on political Islamic groups to boost science

Nature 518, 7540 (2015). http://www.nature.com/doifinder/10.1038/518457a

Author: Dyna Rochmyaningsih

For science to realize its potential in the Muslim world, attitudes need to change at a societal level, not just an individual one, says Dyna Rochmyaningsih.

Categories: Literature

Wanted: 80,000 British babies for massive study

Nature - Tue, 02/24/2015 - 01:00

Wanted: 80,000 British babies for massive study

Nature 518, 7540 (2015). http://www.nature.com/doifinder/10.1038/518463a

Author: Helen Pearson

UK launches effort to track children from birth, months after US counterpart closes.

Categories: Literature

Large-scale Pumping Can Return Oxygen To Deep Waters, Scientists Say

Yale Environment 360 - Mon, 02/23/2015 - 11:42

A team of Danish and Swedish scientists reports that they have restored oxygen to the waters

Deploying instruments in Byfjord, Sweden. of a deep fjord that had suffered from a long-term lack of oxygen. The researchers used large pumps to mix oxygen-rich surface water into the deeper parts of the fjord's water column — which had long been anoxic due to its depth and geological setting — and after only two months higher oxygen concentrations became detectable in the bottom waters. "In the later phase of the experiment the entire water column began to look healthy," the researchers said, noting that bacterial species that live in well-oxygenated waters had begun to appear. Low oxygen levels make waters uninhabitable to most forms of life, and anoxic waters often harbor only a few types of bacteria, some of which produce significant levels of greenhouse gases.

Categories: Environmental News

Why U.S. East Coast Should Stay Off-Limits to Oil Drilling

Yale Environment 360 - Mon, 02/23/2015 - 07:30

It’s not just the potential for a catastrophic spill that makes President Obama’s proposal to open Atlantic Ocean waters to oil exploration such a bad idea. What’s worse is the cumulative impact on coastal ecosystems that an active oil industry would bring. BY CARL SAFINA

Categories: Environmental News

Wind Produced 10 Percent of Texas Electricity in 2014, Grid Operator Says

Yale Environment 360 - Fri, 02/20/2015 - 10:56

More than 10 percent of the electricity used in Texas last year came from wind turbines, according to the Electric

General locations of wind plants in Texas. Reliability Council of Texas, which operates the state's electric grid. Wind's share of the Texas electric mix grew from just over 6 percent in 2009 to 10.6 percent in 2014. During that period, wind power generation actually doubled — rising from 18.8 million megawatt-hours to 36.1 million — while total electricity generation in Texas also rose by 11 percent. The share of electricity generated by wind power in Texas is more than double the U.S. figure of 4.4 percent. The growth in wind generation in Texas is a result of new wind plants coming online and grid expansions that have allowed more wind power to flow through the system to consumers, the council said.

Categories: Environmental News

New York City Set for Major Sea Level Rise By 2050s, Report Concludes

Yale Environment 360 - Thu, 02/19/2015 - 11:22

The waters surrounding New York City are on track to rise 11 to 21 inches by the 2050s, according to an analysis based on

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Future NYC flood zones NASA climate change models. The city's average temperature, which has increased by 3.4 degrees F since 1900, is set to rise another 5 degrees F by the 2050s, the report says, and annual precipitation is also likely to rise significantly over that period. New York City has already seen sea levels rise by over 1 foot since 1900 — nearly twice the average global rate, according to the report, which was published by the New York City Panel on Climate Change. Mayor Bill de Blasio said the report highlights the urgency of mitigating climate change and adapting to its risks, and he announced a commitment to cut the city's emissions by 80 percent by 2050.

Categories: Environmental News

Scientists are cautious about public outreach

Nature - Thu, 02/19/2015 - 01:00

Scientists are cautious about public outreach

Nature 518, 7540 (2015). doi:10.1038/518459f

Author: Chris Woolston

Researchers online react to a survey showing mixed feelings about news and social media.

Categories: Literature

Disease-Carrying Ticks Expand Range and Emerge Earlier in Warmer Climate

Yale Environment 360 - Wed, 02/18/2015 - 10:56

Warmer spring temperatures in the northeastern U.S. are leading to shifts in the emergence of ticks that carry Lyme

Adult blacklegged tick disease, and milder weather is allowing ticks to spread into new geographic regions, according to findings published this week. The data — which span 19 years and include observations of more than 447,000 ticks — show that the insects emerged nearly three weeks earlier in warmer years. And when fall temperatures were mild, a smaller percentage of larval ticks entered dormancy and waited until spring to feed, the study found. "Here in the Northeast, warming is already having an effect, and people need to be tick-vigilant before May, as potentially infected nymphal ticks are searching for their blood meals earlier and earlier," said co-author Richard S. Ostfeld, an ecologist at the Cary Institute.

Categories: Environmental News

Interview: Why Ocean Health Is Better, and Worse, Than You Think

Yale Environment 360 - Wed, 02/18/2015 - 08:22

In a recent groundbreaking study in Science, a group of marine experts — including lead author Douglas Douglas McCauley McCauley — delivered a sobering message: The world’s oceans are on the verge of major change that could cause irreparable damage to marine life. While ocean ecosystems are still largely intact, the marine world is facing unprecedented disturbances, including ocean acidification and habitat destruction from deep-sea mining, oil and gas drilling, development, and aquaculture. In an interview with Yale Environment 360, McCauley discusses the parallels of the loss of wildlife on land and at sea and explains why creating marine reserves and establishing international ocean zoning regulations would help blunt the damage from a looming “marine industrial revolution.”
Read the interview.

Categories: Environmental News

Telling stories

Nature - Wed, 02/18/2015 - 02:00

Telling stories

Nature 518, 7538 (2015). doi:10.1038/518137a

The UK Research Excellence Framework’s focus on impact is a useful reminder of all the ways that science can help society — both economically and by other means.

Categories: Literature

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