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Materials research: Batteries warm up

Nature - Wed, 08/06/2014 - 00:00

Materials research: Batteries warm up

Nature 512, 7512 (2014). doi:10.1038/nj7512-105a

Author: Katharine Gammon

Interest in energy-storage research is growing, opening up opportunities for chemists with interdisciplinary skills.

Categories: Literature

Research and development: Outsourcing trends

Nature - Wed, 08/06/2014 - 00:00

Research and development: Outsourcing trends

Nature 512, 7512 (2014). doi:10.1038/nj7512-106a

US contract research organizations are multiplying to meet drug-makers' outsourcing needs.

Categories: Literature

Employment law: Graduate rights

Nature - Wed, 08/06/2014 - 00:00

Employment law: Graduate rights

Nature 512, 7512 (2014). doi:10.1038/nj7512-106b

US association argues for graduate assistants' right to unionize.

Categories: Literature

Your application for eternal life has been partially approved

Nature - Wed, 08/06/2014 - 00:00

Your application for eternal life has been partially approved

Nature 512, 7512 (2014). doi:10.1038/512108a

Author: James Wesley Rogers

All that matters.

Categories: Literature

Bias towards large genes in autism

Nature - Wed, 08/06/2014 - 00:00

Bias towards large genes in autism

Nature 512, 7512 (2014). doi:10.1038/nature13583

Authors: Shahar Shohat & Sagiv Shifman

Arising from I. F. King et al.Nature501, 58–62 (2013); doi:10.1038/nature12504In an important recent paper, King et al. reported that inhibition of TOP1 and other topoisomerases reduces the expression of extremely long genes. They also showed that the list of large genes affected by TOP1 inhibition is enriched with candidate genes for autism spectrum disorders (ASD); however, the list of candidate genes that was used contains many genes with limited evidence for association with ASD. Here we demonstrate that the size of the genes among ASD candidate genes is biased towards extremely large genes only for genes identified to be disrupted by copy number variations (CNVs). Thus, our analysis suggests that the association between large genes and ASD is mainly driven by the method that implicated the genes in ASD. There is a Reply to this Brief Communication Arising by Zylka, M. J. et al. Nature512,http://dx.doi.org/10.1038/nature13584 (2014).

Categories: Literature

Zylka et al. reply

Nature - Wed, 08/06/2014 - 00:00

Zylka et al. reply

Nature 512, 7512 (2014). doi:10.1038/nature13584

Authors: Mark J. Zylka, Ben D. Philpot & Ian F. King

Replying to S. Shohat & S. Shifman Nature512, http://dx.doi.org/10.1038/nature13583 (2014)Shohat and Shifman’s analysis indicates that long autism spectrum disorder (ASD) genes are overrepresented in the SFARI Gene/AutDB database (as of 11 December 2013) owing to the discovery method. We agree with their analysis and with the need to consider the strength of evidence behind each candidate gene. When our study was underway, SFARI Gene provided the only comprehensive list of autism candidate genes with confidence values. Subsequent to our publication, more genes have been added to this database and scored, highlighting the rapid pace of advances in the ASD field and the changing confidence behind each ASD gene.

Categories: Literature

Correction

Nature - Wed, 08/06/2014 - 00:00

Correction

Nature 512, 7512 (2014). http://www.nature.com/doifinder/10.1038/512018b

In the News story ‘Biosafety controls come under fire’ (Nature511, 515–516; 2014) the ‘European Biosafety Organization’ should have been the ‘European Biosafety Association’. And the story ‘Project drills deep into coming quake’ (Nature511, 516–517; 2014) gave the

Categories: Literature

Correction

Nature - Wed, 08/06/2014 - 00:00

Correction

Nature 512, 7512 (2014). http://www.nature.com/doifinder/10.1038/512028f

In the Outlook article 'Funding by numbers' (Nature511, S52–S53;10.1038/511S52a2014), the vertical axis of the graphic 'Scholarly spending' was wrongly labelled. It should have read 'Percentage of GDP spent on research and development'.

Categories: Literature

Materials chemistry: Seeds of selective nanotube growth

Nature - Wed, 08/06/2014 - 00:00

Materials chemistry: Seeds of selective nanotube growth

Nature 512, 7512 (2014). doi:10.1038/512030a

Authors: James M. Tour

'Seed' molecules have been made that enable synthesis of just one kind of single-walled carbon nanotube, rather than a mixture of species. This paves the way for the preparation of pure samples of any nanotube species. See Letterp.61

Categories: Literature

Neurodegeneration: Alzheimer's disease under strain

Nature - Wed, 08/06/2014 - 00:00

Neurodegeneration: Alzheimer's disease under strain

Nature 512, 7512 (2014). doi:10.1038/512032a

Authors: Adriano Aguzzi

Two studies of amyloid-β protein aggregates, which cause Alzheimer's disease, find that different conformations of the aggregates can define different strains of the disorder, drawing parallels with prion diseases.

Categories: Literature

Astrophysics: Portrait of a doomed star

Nature - Wed, 08/06/2014 - 00:00

Astrophysics: Portrait of a doomed star

Nature 512, 7512 (2014). doi:10.1038/512034a

Authors: Stephen Justham

Some stars explode in thermonuclear supernovae, but understanding of why this occurs comes mainly from indirect clues. Now, the progenitor of a member of a strange class of such explosions may have been detected directly. See Letterp.54

Categories: Literature

A luminous, blue progenitor system for the type Iax supernova 2012Z

Nature - Wed, 08/06/2014 - 00:00

A luminous, blue progenitor system for the type Iax supernova 2012Z

Nature 512, 7512 (2014). doi:10.1038/nature13615

Authors: Curtis McCully, Saurabh W. Jha, Ryan J. Foley, Lars Bildsten, Wen-fai Fong, Robert P. Kirshner, G. H. Marion, Adam G. Riess & Maximilian D. Stritzinger

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon–oxygen white dwarfs that do not completely unbind the star, implying that they are ‘less successful’ versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

Categories: Literature

Tunable spin–spin interactions and entanglement of ions in separate potential wells

Nature - Wed, 08/06/2014 - 00:00

Tunable spin–spin interactions and entanglement of ions in separate potential wells

Nature 512, 7512 (2014). doi:10.1038/nature13565

Authors: A. C. Wilson, Y. Colombe, K. R. Brown, E. Knill, D. Leibfried & D. J. Wineland

Quantum simulation—the use of one quantum system to simulate a less controllable one—may provide an understanding of the many quantum systems which cannot be modelled using classical computers. Considerable progress in control and manipulation has been achieved for various quantum systems, but one of the remaining challenges is the implementation of scalable devices. In this regard, individual ions trapped in separate tunable potential wells are promising. Here we implement the basic features of this approach and demonstrate deterministic tuning of the Coulomb interaction between two ions, independently controlling their local wells. The scheme is suitable for emulating a range of spin–spin interactions, but to characterize the performance of our set-up we select one that entangles the internal states of the two ions with a fidelity of 0.82(1) (the digit in parentheses shows the standard error of the mean). Extension of this building block to a two-dimensional network, which is possible using ion-trap microfabrication processes, may provide a new quantum simulator architecture with broad flexibility in designing and scaling the arrangement of ions and their mutual interactions. To perform useful quantum simulations, including those of condensed-matter phenomena such as the fractional quantum Hall effect, an array of tens of ions might be sufficient.

Categories: Literature

Controlled synthesis of single-chirality carbon nanotubes

Nature - Wed, 08/06/2014 - 00:00

Controlled synthesis of single-chirality carbon nanotubes

Nature 512, 7512 (2014). doi:10.1038/nature13607

Authors: Juan Ramon Sanchez-Valencia, Thomas Dienel, Oliver Gröning, Ivan Shorubalko, Andreas Mueller, Martin Jansen, Konstantin Amsharov, Pascal Ruffieux & Roman Fasel

Over the past two decades, single-walled carbon nanotubes (SWCNTs) have received much attention because their extraordinary properties are promising for numerous applications. Many of these properties depend sensitively on SWCNT structure, which is characterized by the chiral index (n,m) that denotes the length and orientation of the circumferential vector in the hexagonal carbon lattice. Electronic properties are particularly strongly affected, with subtle structural changes switching tubes from metallic to semiconducting with various bandgaps. Monodisperse ‘single-chirality’ (that is, with a single (n,m) index) SWCNTs are thus needed to fully exploit their technological potential. Controlled synthesis through catalyst engineering, end-cap engineering or cloning strategies, and also tube sorting based on chromatography, density-gradient centrifugation, electrophoresis and other techniques, have delivered SWCNT samples with narrow distributions of tube diameter and a large fraction of a predetermined tube type. But an effective pathway to truly monodisperse SWCNTs remains elusive. The use of template molecules to unambiguously dictate the diameter and chirality of the resulting nanotube holds great promise in this regard, but has hitherto had only limited practical success. Here we show that this bottom-up strategy can produce targeted nanotubes: we convert molecular precursors into ultrashort singly capped (6,6) ‘armchair’ nanotube seeds using surface-catalysed cyclodehydrogenation on a platinum (111) surface, and then elongate these during a subsequent growth phase to produce single-chirality and essentially defect-free SWCNTs with lengths up to a few hundred nanometres. We expect that our on-surface synthesis approach will provide a route to nanotube-based materials with highly optimized properties for applications such as light detectors, photovoltaics, field-effect transistors and sensors.

Categories: Literature

A global ocean inventory of anthropogenic mercury based on water column measurements

Nature - Wed, 08/06/2014 - 00:00

A global ocean inventory of anthropogenic mercury based on water column measurements

Nature 512, 7512 (2014). doi:10.1038/nature13563

Authors: Carl H. Lamborg, Chad R. Hammerschmidt, Katlin L. Bowman, Gretchen J. Swarr, Kathleen M. Munson, Daniel C. Ohnemus, Phoebe J. Lam, Lars-Eric Heimbürger, Micha J. A. Rijkenberg & Mak A. Saito

Mercury is a toxic, bioaccumulating trace metal whose emissions to the environment have increased significantly as a result of anthropogenic activities such as mining and fossil fuel combustion. Several recent models have estimated that these emissions have increased the oceanic mercury inventory by 36–1,313 million moles since the 1500s. Such predictions have remained largely untested owing to a lack of appropriate historical data and natural archives. Here we report oceanographic measurements of total dissolved mercury and related parameters from several recent expeditions to the Atlantic, Pacific, Southern and Arctic oceans. We find that deep North Atlantic waters and most intermediate waters are anomalously enriched in mercury relative to the deep waters of the South Atlantic, Southern and Pacific oceans, probably as a result of the incorporation of anthropogenic mercury. We estimate the total amount of anthropogenic mercury present in the global ocean to be 290 ± 80 million moles, with almost two-thirds residing in water shallower than a thousand metres. Our findings suggest that anthropogenic perturbations to the global mercury cycle have led to an approximately 150 per cent increase in the amount of mercury in thermocline waters and have tripled the mercury content of surface waters compared to pre-anthropogenic conditions. This information may aid our understanding of the processes and the depths at which inorganic mercury species are converted into toxic methyl mercury and subsequently bioaccumulated in marine food webs.

Categories: Literature

Forests Already Seeing Effects of Climate Change, European Researchers Say

Yale Environment 360 - Tue, 08/05/2014 - 11:31

Damage from wind, bark beetles, and wildfires has increased drastically in Europe's forests in recent years, and climate change is the driving factor, according to

Click to Enlarge

European forest damage research published in Nature Climate Change. These disturbances have become increasingly acute over the last 40 years, damaging 56 million cubic meters of timber per year from 2002 to 2010. And researchers estimate that an additional million cubic meters of timber — roughly 7,000 soccer fields of forest — will likely be destroyed each year over the next 20 years if climate change trends continue. Damage from forest fires in particular is expected to increase on the Iberian Peninsula, while bark beetle damage will likely increase most strongly in the Alps. Wind damage is predicted to rise most notably in Central and Western Europe, the study found. To compound the problem, as more forests are damaged, there will be fewer healthy trees available to remove the climate-warming carbon dioxide from the atmosphere, the researchers note.

Categories: Environmental News

Home-brew tests need regulation

Nature - Tue, 08/05/2014 - 00:00

Home-brew tests need regulation

Nature 512, 7512 (2014). doi:10.1038/512005a

A US proposal to regulate medical diagnostics from individual labs reflects the tests’ growing complexity. Such guidance should be welcomed, not resisted.

Categories: Literature

Seven days: 1–7 August 2014

Nature - Tue, 08/05/2014 - 00:00

Seven days: 1–7 August 2014

Nature 512, 7512 (2014). http://www.nature.com/doifinder/10.1038/512010a

The week in science: Death of top Japanese stem-cell scientist; instruments picked for Mars rover; and drought tightens grip on California.

Categories: Literature

Binary star to spill celestial secrets

Nature - Tue, 08/05/2014 - 00:00

Binary star to spill celestial secrets

Nature 512, 7512 (2014). http://www.nature.com/doifinder/10.1038/512013a

Author: Alexandra Witze

Close approach and violent interaction of stars in η Carinae system will provide rare insight into stellar enigma.

Categories: Literature

California Takes Steps to Curb Lawn Watering During Severe Drought

Yale Environment 360 - Mon, 08/04/2014 - 11:02

In the midst of a severe, long-term drought, California is taking unprecedented steps to discourage watering of

A drought-resistant yard residential lawns, with some areas offering residents substantial cash incentives for installing water-saving landscaping, AFP reports. The "Cash in Your Lawn" program in Los Angeles offers residents up to $6,000 ($3 per square foot) for replacing their lawns with drought-tolerant plants, rocks, and pebbles. Throughout the state, Governor Jerry Brown recently prohibited lawn watering more than two times per week and banned fines for brown lawns, which homeowner associations sometimes impose with the intent of improving a neighborhood's appearance. The drought, currently in its third year, threatens the water supply of California's 38 million residents. Agricultural regions have already seen severe water reductions, placing extra pressure on the state's groundwater reserves.

Categories: Environmental News

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