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Student debt rising

Nature - Wed, 04/09/2014 - 00:00

Student debt rising

Nature 508, 7495 (2014). doi:10.1038/nj7495-277c

US postgraduate-student debt continues to escalate.

Categories: Literature

Grant obstacles

Nature - Wed, 04/09/2014 - 00:00

Grant obstacles

Nature 508, 7495 (2014). doi:10.1038/nj7495-277d

Australian researchers decry oppressive grant-application process.

Categories: Literature

How Kameron Layas rode out the crash

Nature - Wed, 04/09/2014 - 00:00

How Kameron Layas rode out the crash

Nature 508, 7495 (2014). doi:10.1038/508280a

Author: Rahul Kanakia

Shameful behaviour.

Categories: Literature

Correction

Nature - Wed, 04/09/2014 - 00:00

Correction

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508163b

The affiliation for Joshua Tewksbury in the Editorial ‘Natural decline’ (Nature508, 7–8; 2014) should have said he is director of the Luc Hoffmann Institute at the conservation group WWF in Gland, Switzerland.

Categories: Literature

Biogeoscience: Africa's greenhouse-gas budget is in the red

Nature - Wed, 04/09/2014 - 00:00

Biogeoscience: Africa's greenhouse-gas budget is in the red

Nature 508, 7495 (2014). doi:10.1038/508192a

Authors: Cheikh Mbow

Africa had been thought to be a potentially large carbon sink — of great value in efforts to mitigate carbon dioxide emissions. But an analysis now reveals that it could be a net source of greenhouse gases that will increase global warming.

Categories: Literature

Metabolism: Targeting a fat-accumulation gene

Nature - Wed, 04/09/2014 - 00:00

Metabolism: Targeting a fat-accumulation gene

Nature 508, 7495 (2014). doi:10.1038/508194a

Authors: Charles Brenner

An enzyme that links two metabolic hubs has been found to be upregulated in the fat cells of overweight mice. Inhibition of the gene encoding this enzyme protects mice from diet-induced obesity. See Letter p.258

Categories: Literature

Quantum physics: A strong hybrid couple

Nature - Wed, 04/09/2014 - 00:00

Quantum physics: A strong hybrid couple

Nature 508, 7495 (2014). doi:10.1038/508195a

Authors: Luming Duan

A single atom in an optical cavity is shown to interact strongly with an incoming photon and to switch the photon's state. This finding opens up a path towards optical quantum computation and quantum networks. See Letters p.237 & p.241

Categories: Literature

A quantum gate between a flying optical photon and a single trapped atom

Nature - Wed, 04/09/2014 - 00:00

A quantum gate between a flying optical photon and a single trapped atom

Nature 508, 7495 (2014). doi:10.1038/nature13177

Authors: Andreas Reiserer, Norbert Kalb, Gerhard Rempe & Stephan Ritter

The steady increase in control over individual quantum systems supports the promotion of a quantum technology that could provide functionalities beyond those of any classical device. Two particularly promising applications have been explored during the past decade: photon-based quantum communication, which guarantees unbreakable encryption but which still has to be scaled to high rates over large distances, and quantum computation, which will fundamentally enhance computability if it can be scaled to a large number of quantum bits (qubits). It was realized early on that a hybrid system of light qubits and matter qubits could solve the scalability problem of each field—that of communication by use of quantum repeaters, and that of computation by use of an optical interconnect between smaller quantum processors. To this end, the development of a robust two-qubit gate that allows the linking of distant computational nodes is “a pressing challenge”. Here we demonstrate such a quantum gate between the spin state of a single trapped atom and the polarization state of an optical photon contained in a faint laser pulse. The gate mechanism presented is deterministic and robust, and is expected to be applicable to almost any matter qubit. It is based on reflection of the photonic qubit from a cavity that provides strong light–matter coupling. To demonstrate its versatility, we use the quantum gate to create atom–photon, atom–photon–photon and photon–photon entangled states from separable input states. We expect our experiment to enable various applications, including the generation of atomic and photonic cluster states and Schrödinger-cat states, deterministic photonic Bell-state measurements, scalable quantum computation and quantum communication using a redundant quantum parity code.

Categories: Literature

Nanophotonic quantum phase switch with a single atom

Nature - Wed, 04/09/2014 - 00:00

Nanophotonic quantum phase switch with a single atom

Nature 508, 7495 (2014). doi:10.1038/nature13188

Authors: T. G. Tiecke, J. D. Thompson, N. P. de Leon, L. R. Liu, V. Vuletić & M. D. Lukin

By analogy to transistors in classical electronic circuits, quantum optical switches are important elements of quantum circuits and quantum networks. Operated at the fundamental limit where a single quantum of light or matter controls another field or material system, such a switch may enable applications such as long-distance quantum communication, distributed quantum information processing and metrology, and the exploration of novel quantum states of matter. Here, by strongly coupling a photon to a single atom trapped in the near field of a nanoscale photonic crystal cavity, we realize a system in which a single atom switches the phase of a photon and a single photon modifies the atom’s phase. We experimentally demonstrate an atom-induced optical phase shift that is nonlinear at the two-photon level, a photon number router that separates individual photons and photon pairs into different output modes, and a single-photon switch in which a single ‘gate’ photon controls the propagation of a subsequent probe field. These techniques pave the way to integrated quantum nanophotonic networks involving multiple atomic nodes connected by guided light.

Categories: Literature

Nicotinamide N-methyltransferase knockdown protects against diet-induced obesity

Nature - Wed, 04/09/2014 - 00:00

Nicotinamide N-methyltransferase knockdown protects against diet-induced obesity

Nature 508, 7495 (2014). doi:10.1038/nature13198

Authors: Daniel Kraus, Qin Yang, Dong Kong, Alexander S. Banks, Lin Zhang, Joseph T. Rodgers, Eija Pirinen, Thomas C. Pulinilkunnil, Fengying Gong, Ya-chin Wang, Yana Cen, Anthony A. Sauve, John M. Asara, Odile D. Peroni, Brett P. Monia, Sanjay Bhanot, Leena Alhonen, Pere Puigserver & Barbara B. Kahn

In obesity and type 2 diabetes, Glut4 glucose transporter expression is decreased selectively in adipocytes. Adipose-specific knockout or overexpression of Glut4 alters systemic insulin sensitivity. Here we show, using DNA array analyses, that nicotinamide N-methyltransferase (Nnmt) is the most strongly reciprocally regulated gene when comparing gene expression in white adipose tissue (WAT) from adipose-specific Glut4-knockout or adipose-specific Glut4-overexpressing mice with their respective controls. NNMT methylates nicotinamide (vitamin B3) using S-adenosylmethionine (SAM) as a methyl donor. Nicotinamide is a precursor of NAD+, an important cofactor linking cellular redox states with energy metabolism. SAM provides propylamine for polyamine biosynthesis and donates a methyl group for histone methylation. Polyamine flux including synthesis, catabolism and excretion, is controlled by the rate-limiting enzymes ornithine decarboxylase (ODC) and spermidine–spermine N1-acetyltransferase (SSAT; encoded by Sat1) and by polyamine oxidase (PAO), and has a major role in energy metabolism. We report that NNMT expression is increased in WAT and liver of obese and diabetic mice. Nnmt knockdown in WAT and liver protects against diet-induced obesity by augmenting cellular energy expenditure. NNMT inhibition increases adipose SAM and NAD+ levels and upregulates ODC and SSAT activity as well as expression, owing to the effects of NNMT on histone H3 lysine 4 methylation in adipose tissue. Direct evidence for increased polyamine flux resulting from NNMT inhibition includes elevated urinary excretion and adipocyte secretion of diacetylspermine, a product of polyamine metabolism. NNMT inhibition in adipocytes increases oxygen consumption in an ODC-, SSAT- and PAO-dependent manner. Thus, NNMT is a novel regulator of histone methylation, polyamine flux and NAD+-dependent SIRT1 signalling, and is a unique and attractive target for treating obesity and type 2 diabetes.

Categories: Literature

'Living Fences' Have Dramatically Cut Livestock and Lion Killings in Tanzania

Yale Environment 360 - Tue, 04/08/2014 - 11:48

A novel, low-tech idea is helping Tanzania's lion population rebound: So-called "living fences" — which enclose livestock and are constructed of actively growing trees and chain-link fencing — have cut lion A Masai villager installs a living fence. attacks and retaliatory killings by more than 85 percent in the areas they've been installed, the Guardian reports. Traditionally, the Masai have built livestock enclosures out of thorny acacia trees, but those fences are relatively fragile. Chain-link fencing alone is more durable, but leopards and small lions can scale the fences, and hyenas can tunnel in below. By interweaving actively growing African myrrh trees with the chain link fencing, the Masai have created a barrier that lions can't climb over, and their root systems prevent predators from digging under the fence. Because livestock predation has been cut, communities that had been killing six or seven lions annually now kill, on average, less than one, leading to a rebound in lion populations.

Categories: Environmental News

A Personal Note on Peter Matthiessen, Who Wrote Eloquently of the Natural World

Yale Environment 360 - Tue, 04/08/2014 - 07:31

For an editor, the prospect of working with Peter Matthiessen was intimidating. He was one of our finest writers, and he wrote with such poetic precision and lyrical grace that at first it felt presumptuous to propose Peter Matthiessen any changes to his writing at all. That feeling was heightened by his strong physical presence — an odd mix of Manhattan patrician, rugged outdoorsman, and Zen priest (all of which he was). And yet when I worked as his editor on several magazine articles in the 1990s, it was an immensely satisfying experience. He listened Zen-like, carefully considering all my editing suggestions (with him, they were suggestions only), and to my delight, accepted almost all of them. Matthiessen died on April 5 at the age of 86, near the Long Island waters he so loved to fish. Read more of e360 editor Roger Cohn’s appreciation of Matthiessen.

Categories: Environmental News

A Note on Peter Matthiessen, Who Wrote Elegantly of the Natural World

Yale Environment 360 - Tue, 04/08/2014 - 07:31

For an editor, the prospect of working with Peter Matthiessen was intimidating. He was one of our finest writers, and he wrote with such poetic precision and lyrical grace that at first it felt presumptuous to propose Peter Matthiessen any changes to his writing at all. That feeling was heightened by his strong physical presence — an odd mix of Manhattan patrician, rugged outdoorsman, and Zen priest (all of which he was). And yet when I worked as his editor on several magazine articles in the 1990s, it was an immensely satisfying experience. He listened Zen-like, carefully considering all my editing suggestions (with him, they were suggestions only), and to my delight, accepted almost all of them. Matthiessen died last Saturday at the age of 86, near the Long Island waters he so loved to fish. Read more of e360 editor Roger Cohn’s appreciation of Matthiessen.

Categories: Environmental News

Look back in wonder

Nature - Tue, 04/08/2014 - 00:00

Look back in wonder

Nature 508, 7495 (2014). doi:10.1038/508149a

The launch of the first Sentinel satellite heralds an era in which detailed data on everything from earthquakes to urbanization will be freely available to anyone interested in Earth’s future.

Categories: Literature

Political science

Nature - Tue, 04/08/2014 - 00:00

Political science

Nature 508, 7495 (2014). doi:10.1038/508149b

Russia deserves to be sanctioned, but halting scientific collaboration is not the way to do it.

Categories: Literature

NIH stem-cell programme closes

Nature - Tue, 04/08/2014 - 00:00

NIH stem-cell programme closes

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508157a

Author: Sara Reardon

Director resigns as just one clinical-trial award is made.

Categories: Literature

E-cigarettes affect cells

Nature - Tue, 04/08/2014 - 00:00

E-cigarettes affect cells

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508159a

Author: Daniel Cressey

Questions raised over health effects of devices.

Categories: Literature

Earth observation enters next phase

Nature - Tue, 04/08/2014 - 00:00

Earth observation enters next phase

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508160a

Author: Declan Butler

Expectations high as first European Sentinel satellite launches.

Categories: Literature

Western science severs ties with Russia

Nature - Tue, 04/08/2014 - 00:00

Western science severs ties with Russia

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508162a

Author: Quirin Schiermeier

Country’s science renaissance threatened as NATO and NASA suspend links.

Categories: Literature

Time running out for rarest primate

Nature - Tue, 04/08/2014 - 00:00

Time running out for rarest primate

Nature 508, 7495 (2014). http://www.nature.com/doifinder/10.1038/508163a

Author: Daniel Cressey

Rescue bid launched to save Hainan gibbon from becoming first ape driven to extinction by humans.

Categories: Literature

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