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Crenothrix are major methane consumers in stratified lakes

ISME - Tue, 08/15/2017 - 00:00

Crenothrix are major methane consumers in stratified lakes

The ISME Journal 11, 2124 (September 2017). doi:10.1038/ismej.2017.77

Authors: Kirsten Oswald, Jon S Graf, Sten Littmann, Daniela Tienken, Andreas Brand, Bernhard Wehrli, Mads Albertsen, Holger Daims, Michael Wagner, Marcel MM Kuypers, Carsten J Schubert & Jana Milucka

Categories: Literature

Succession in the petroleum reservoir microbiome through an oil field production lifecycle

ISME - Tue, 08/15/2017 - 00:00

Succession in the petroleum reservoir microbiome through an oil field production lifecycle

The ISME Journal 11, 2141 (September 2017). doi:10.1038/ismej.2017.78

Authors: Adrien Vigneron, Eric B Alsop, Bartholomeus P Lomans, Nikos C Kyrpides, Ian M Head & Nicolas Tsesmetzis

Categories: Literature

In situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torques

ISME - Tue, 08/15/2017 - 00:00

In situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torques

The ISME Journal 11, 2155 (September 2017). doi:10.1038/ismej.2017.65

Authors: David J Burr, Andrew Martin, Elizabeth W Maas & Ken G Ryan

Categories: Literature

Monkey Species Not Seen Alive for 80 Years Rediscovered in the Amazon

Yale Environment 360 - Mon, 08/14/2017 - 11:02

Scientists have rediscovered a species of monkey in the Brazilian Amazon not seen alive since 1936, according to reporting by Mongabay.

Read more on E360 →

Categories: Environmental News

Thirty Years After the Montreal Protocol, Solving the Ozone Problem Remains Elusive

Yale Environment 360 - Mon, 08/14/2017 - 04:00

Despite a ban on chemicals like chlorofluorocarbons, the ozone hole over Antarctica remains nearly as large as it did when the Montreal Protocol was signed in 1987. Scientists now warn of new threats to the ozone layer, including widespread use of ozone-eating chemicals not covered by the treaty.

Read more on E360 →

Categories: Environmental News

Budget cuts fuel frustration among Japan’s academics

Nature - Mon, 08/14/2017 - 00:00

Budget cuts fuel frustration among Japan’s academics

Nature 548, 7667 (2017). doi:10.1038/nature.2017.22444

Funding trouble at flagship research centre reflects a broader malaise in the country’s scientific priorities that must be addressed.

Categories: Literature

Australian Bank Faces Lawsuit For Not Disclosing Climate Risks

Yale Environment 360 - Fri, 08/11/2017 - 12:39

One of Australia’s largest banks is being sued for failing to disclose to shareholders the risk climate change poses to its financial interests, Climate Change News reports.

Read more on E360 →

Categories: Environmental News

Utility Companies Prepare for U.S. Eclipse and Drop in Solar Power

Yale Environment 360 - Thu, 08/10/2017 - 10:25

Utility companies in solar-heavy states like California, New Jersey, and North Carolina are gearing up for the eclipse traversing the U.S. later this month, which could block an estimated 9,000 megawatts of solar power, enough to supply 7 million homes.

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Categories: Environmental News

In a Rare U.S. Preserve, Water Pressures Mount As Development Closes In

Yale Environment 360 - Thu, 08/10/2017 - 04:00

The largest expanse of open space in the U.S.’s heavily populated Northeast corridor is the Pine Barrens of New Jersey. But with development encroaching on the Pineland’s main aquifer and its rare wetland habitats, some conservationists say it’s time to limit growth in the surrounding region.

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Categories: Environmental News

Massive El Niño sent greenhouse-gas emissions soaring

Nature - Thu, 08/10/2017 - 00:00

Massive El Niño sent greenhouse-gas emissions soaring

Nature 548, 7667 (2017). http://www.nature.com/doifinder/10.1038/nature.2017.22440

Author: Gabriel Popkin

Disruptive weather pattern in 2014–2016 spurred tropical forests to pump out 3 billion tonnes of carbon.

Categories: Literature

US biomedical-research facilities unprepared for attacks and natural disasters

Nature - Thu, 08/10/2017 - 00:00

US biomedical-research facilities unprepared for attacks and natural disasters

Nature 548, 7667 (2017). http://www.nature.com/doifinder/10.1038/nature.2017.22446

Author: Sara Reardon

Science panel says institutions need to do more to prevent and mitigate damage to research equipment and animals.

Categories: Literature

Thousands across India march in support of science

Nature - Wed, 08/09/2017 - 00:00

Thousands across India march in support of science

Nature 548, 7667 (2017). http://www.nature.com/doifinder/10.1038/nature.2017.22439

Author: T. V. Padma

Protesters demand respect for research — but some scientists were told to stay away.

Categories: Literature

Climate science: Origins of Atlantic decadal swings

Nature - Wed, 08/09/2017 - 00:00

Climate science: Origins of Atlantic decadal swings

Nature 548, 7667 (2017). doi:10.1038/nature23538

Authors: Gabriel A. Vecchi, Thomas L. Delworth & Ben Booth

Temperature variability in the North Atlantic Ocean is the result of many competing physical processes, but the relative roles of these processes is a source of contention. Here, scientists present two perspectives on the debate.

Categories: Literature

Neurobiology: A bitter–sweet symphony

Nature - Wed, 08/09/2017 - 00:00

Neurobiology: A bitter–sweet symphony

Nature 548, 7667 (2017). doi:10.1038/nature23537

Authors: Jiefu Li & Liqun Luo

Information about taste sensations, such as bitter or sweet, is relayed from the mouse tongue to the brain through taste-specific pathways. It emerges that semaphorin proteins guide the wiring of these pathways. See Letter p.330

Categories: Literature

New gliding mammaliaforms from the Jurassic

Nature - Wed, 08/09/2017 - 00:00

New gliding mammaliaforms from the Jurassic

Nature 548, 7667 (2017). doi:10.1038/nature23476

Authors: Qing-Jin Meng, David M. Grossnickle, Di Liu, Yu-Guang Zhang, April I. Neander, Qiang Ji & Zhe-Xi Luo

Stem mammaliaforms are Mesozoic forerunners to mammals, and they offer critical evidence for the anatomical evolution and ecological diversification during the earliest mammalian history. Two new eleutherodonts from the Late Jurassic period have skin membranes and skeletal features that are adapted for gliding. Characteristics of

Categories: Literature

Chaotic dynamics in nanoscale NbO2 Mott memristors for analogue computing

Nature - Wed, 08/09/2017 - 00:00

Chaotic dynamics in nanoscale NbO2 Mott memristors for analogue computing

Nature 548, 7667 (2017). doi:10.1038/nature23307

Authors: Suhas Kumar, John Paul Strachan & R. Stanley Williams

At present, machine learning systems use simplified neuron models that lack the rich nonlinear phenomena observed in biological systems, which display spatio-temporal cooperative dynamics. There is evidence that neurons operate in a regime called the edge of chaos that may be central to complexity, learning efficiency, adaptability and analogue (non-Boolean) computation in brains. Neural networks have exhibited enhanced computational complexity when operated at the edge of chaos, and networks of chaotic elements have been proposed for solving combinatorial or global optimization problems. Thus, a source of controllable chaotic behaviour that can be incorporated into a neural-inspired circuit may be an essential component of future computational systems. Such chaotic elements have been simulated using elaborate transistor circuits that simulate known equations of chaos, but an experimental realization of chaotic dynamics from a single scalable electronic device has been lacking. Here we describe niobium dioxide (NbO2) Mott memristors each less than 100 nanometres across that exhibit both a nonlinear-transport-driven current-controlled negative differential resistance and a Mott-transition-driven temperature-controlled negative differential resistance. Mott materials have a temperature-dependent metal–insulator transition that acts as an electronic switch, which introduces a history-dependent resistance into the device. We incorporate these memristors into a relaxation oscillator and observe a tunable range of periodic and chaotic self-oscillations. We show that the nonlinear current transport coupled with thermal fluctuations at the nanoscale generates chaotic oscillations. Such memristors could be useful in certain types of neural-inspired computation by introducing a pseudo-random signal that prevents global synchronization and could also assist in finding a global minimum during a constrained search. We specifically demonstrate that incorporating such memristors into the hardware of a Hopfield computing network can greatly improve the efficiency and accuracy of converging to a solution for computationally difficult problems.

Categories: Literature

An early modern human presence in Sumatra 73,000–63,000 years ago

Nature - Wed, 08/09/2017 - 00:00

An early modern human presence in Sumatra 73,000–63,000 years ago

Nature 548, 7667 (2017). doi:10.1038/nature23452

Authors: K. E. Westaway, J. Louys, R. Due Awe, M. J. Morwood, G. J. Price, J.-x. Zhao, M. Aubert, R. Joannes-Boyau, T. M. Smith, M. M. Skinner, T. Compton, R. M. Bailey, G. D. van den Bergh, J. de Vos, A. W. G. Pike, C. Stringer, E. W. Saptomo, Y. Rizal, J. Zaim, W. D. Santoso, A. Trihascaryo, L. Kinsley & B. Sulistyanto

Genetic evidence for anatomically modern humans (AMH) out of Africa before 75 thousand years ago (ka) and in island southeast Asia (ISEA) before 60 ka (93–61 ka) predates accepted archaeological records of occupation in the region. Claims that AMH arrived in ISEA before 60 ka (ref. 4) have been supported only by equivocal or non-skeletal evidence. AMH evidence from this period is rare and lacks robust chronologies owing to a lack of direct dating applications, poor preservation and/or excavation strategies and questionable taxonomic identifications. Lida Ajer is a Sumatran Pleistocene cave with a rich rainforest fauna associated with fossil human teeth. The importance of the site is unclear owing to unsupported taxonomic identification of these fossils and uncertainties regarding the age of the deposit, therefore it is rarely considered in models of human dispersal. Here we reinvestigate Lida Ajer to identify the teeth confidently and establish a robust chronology using an integrated dating approach. Using enamel–dentine junction morphology, enamel thickness and comparative morphology, we show that the teeth are unequivocally AMH. Luminescence and uranium-series techniques applied to bone-bearing sediments and speleothems, and coupled uranium-series and electron spin resonance dating of mammalian teeth, place modern humans in Sumatra between 73 and 63 ka. This age is consistent with biostratigraphic estimations, palaeoclimate and sea-level reconstructions, and genetic evidence for a pre-60 ka arrival of AMH into ISEA. Lida Ajer represents, to our knowledge, the earliest evidence of rainforest occupation by AMH, and underscores the importance of reassessing the timing and environmental context of the dispersal of modern humans out of Africa.

Categories: Literature

New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem

Nature - Wed, 08/09/2017 - 00:00

New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem

Nature 548, 7667 (2017). doi:10.1038/nature23483

Authors: Zhe-Xi Luo, Qing-Jin Meng, David M. Grossnickle, Di Liu, April I. Neander, Yu-Guang Zhang & Qiang Ji

Stem mammaliaforms are forerunners to modern mammals, and they achieved considerable ecomorphological diversity in their own right. Recent discoveries suggest that eleutherodontids, a subclade of Haramiyida, were more species-rich during the Jurassic period in Asia than previously recognized. Here we report a new Jurassic eleutherodontid mammaliaform with an unusual mosaic of highly specialized characteristics, and the results of phylogenetic analyses that support the hypothesis that haramiyidans are stem mammaliaforms. The new fossil shows fossilized skin membranes that are interpreted to be for gliding and a mandibular middle ear with a unique character combination previously unknown in mammaliaforms. Incisor replacement is prolonged until well after molars are fully erupted, a timing pattern unique to most other mammaliaforms. In situ molar occlusion and a functional analysis reveal a new mode of dental occlusion: dual mortar–pestle occlusion of opposing upper and lower molars, probably for dual crushing and grinding. This suggests that eleutherodontids are herbivorous, and probably specialized for granivory or feeding on soft plant tissues. The inferred dietary adaptation of eleutherodontid gliders represents a remarkable evolutionary convergence with herbivorous gliders in Theria. These Jurassic fossils represent volant, herbivorous stem mammaliaforms associated with pre-angiosperm plants that appear long before the later, iterative associations between angiosperm plants and volant herbivores in various therian clades.

Categories: Literature

Rewiring the taste system

Nature - Wed, 08/09/2017 - 00:00

Rewiring the taste system

Nature 548, 7667 (2017). doi:10.1038/nature23299

Authors: Hojoon Lee, Lindsey J. Macpherson, Camilo A. Parada, Charles S. Zuker & Nicholas J. P. Ryba

In mammals, taste buds typically contain 50–100 tightly packed taste-receptor cells (TRCs), representing all five basic qualities: sweet, sour, bitter, salty and umami. Notably, mature taste cells have life spans of only 5–20 days and, consequently, are constantly replenished by differentiation of taste stem cells. Given the importance of establishing and maintaining appropriate connectivity between TRCs and their partner ganglion neurons (that is, ensuring that a labelled line from sweet TRCs connects to sweet neurons, bitter TRCs to bitter neurons, sour to sour, and so on), we examined how new connections are specified to retain fidelity of signal transmission. Here we show that bitter and sweet TRCs provide instructive signals to bitter and sweet target neurons via different guidance molecules (SEMA3A and SEMA7A). We demonstrate that targeted expression of SEMA3A or SEMA7A in different classes of TRCs produces peripheral taste systems with miswired sweet or bitter cells. Indeed, we engineered mice with bitter neurons that now responded to sweet tastants, sweet neurons that responded to bitter or sweet neurons responding to sour stimuli. Together, these results uncover the basic logic of the wiring of the taste system at the periphery, and illustrate how a labelled-line sensory circuit preserves signalling integrity despite rapid and stochastic turnover of receptor cells.

Categories: Literature

m6A mRNA methylation controls T cell homeostasis by targeting the IL-7/STAT5/SOCS pathways

Nature - Wed, 08/09/2017 - 00:00

m6A mRNA methylation controls T cell homeostasis by targeting the IL-7/STAT5/SOCS pathways

Nature 548, 7667 (2017). doi:10.1038/nature23450

Authors: Hua-Bing Li, Jiyu Tong, Shu Zhu, Pedro J. Batista, Erin E. Duffy, Jun Zhao, Will Bailis, Guangchao Cao, Lina Kroehling, Yuanyuan Chen, Geng Wang, James P. Broughton, Y. Grace Chen, Yuval Kluger, Matthew D. Simon, Howard Y. Chang, Zhinan Yin & Richard A. Flavell

N6-methyladenosine (m6A) is the most common and abundant messenger RNA modification, modulated by ‘writers’, ‘erasers’ and ‘readers’ of this mark. In vitro data have shown that m6A influences all fundamental aspects of mRNA metabolism, mainly mRNA stability, to determine stem cell fates. However, its in vivo physiological function in mammals and adult mammalian cells is still unknown. Here we show that the deletion of m6A ‘writer’ protein METTL3 in mouse T cells disrupts T cell homeostasis and differentiation. In a lymphopaenic mouse adoptive transfer model, naive Mettl3-deficient T cells failed to undergo homeostatic expansion and remained in the naive state for up to 12 weeks, thereby preventing colitis. Consistent with these observations, the mRNAs of SOCS family genes encoding the STAT signalling inhibitory proteins SOCS1, SOCS3 and CISH were marked by m6A, exhibited slower mRNA decay and showed increased mRNAs and levels of protein expression in Mettl3-deficient naive T cells. This increased SOCS family activity consequently inhibited IL-7-mediated STAT5 activation and T cell homeostatic proliferation and differentiation. We also found that m6A has important roles for inducible degradation of Socs mRNAs in response to IL-7 signalling in order to reprogram naive T cells for proliferation and differentiation. Our study elucidates for the first time, to our knowledge, the in vivo biological role of m6A modification in T-cell-mediated pathogenesis and reveals a novel mechanism of T cell homeostasis and signal-dependent induction of mRNA degradation.

Categories: Literature

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