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Thermal displacement by marine heatwaves 期刊论文
Nature, 2020
作者:  Michael G. Jacox;  Michael A. Alexander;  Steven J. Bograd;  James D. Scott
收藏  |  浏览/下载:7/0  |  提交时间:2020/08/18
HOW CONFERENCES WILL SURVIVE THE CORONAVIRUS SHOCK 期刊论文
NATURE, 2020, 582 (7811) : 166-167
作者:  Amor, Corina;  Feucht, Judith;  Leibold, Josef;  Ho, Yu-Jui;  Zhu, Changyu;  Alonso-Curbelo, Direna;  Mansilla-Soto, Jorge;  Boyer, Jacob A.;  Li, Xiang;  Giavridis, Theodoros;  Kulick, Amanda;  Houlihan, Shauna;  Peerschke, Ellinor;  Friedman, Scott L.;  Ponomarev, Vladimir
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03
Rapid growth of new atmospheric particles by nitric acid and ammonia condensation 期刊论文
NATURE, 2020, 581 (7807) : 184-+
作者:  Liang, Guanxiang;  Zhao, Chunyu;  Zhang, Huanjia;  Mattei, Lisa;  Sherrill-Mix, Scott;  Bittinger, Kyle;  Kessler, Lyanna R.;  Wu, Gary D.;  Baldassano, Robert N.;  DeRusso, Patricia;  Ford, Eileen;  Elovitz, Michal A.;  Kelly, Matthew S.;  Patel, Mohamed Z.;  Mazhani, Tiny;  Gerber, Jeffrey S.;  Kelly, Andrea;  Zemel, Babette S.;  Bushman, Frederic D.
收藏  |  浏览/下载:17/0  |  提交时间:2020/05/20

A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog(1,2), but how it occurs in cities is often puzzling(3). If the growth rates of urban particles are similar to those found in cleaner environments (1-10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below -15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid-base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms(4,5).


  
The lead-up to the Sturtian Snowball Earth: Neoproterozoic chemostratigraphy time-calibrated by the Tambien Group of Ethiopia 期刊论文
GEOLOGICAL SOCIETY OF AMERICA BULLETIN, 2020, 132 (5-6) : 1119-1149
作者:  Park, Yuem;  Swanson-Hysell, Nicholas L.;  MacLennan, Scott A.;  Maloof, Adam C.;  Gebreslassie, Mulubrhan;  Tremblay, Marissa M.;  Schoene, Blair;  Alene, Mulugeta;  Anttila, Eliel S. C.;  Tesema, Tadele;  Haileab, Bereket
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/02
Background heterogeneity and other uncertainties in estimating urban methane flux: results from the Indianapolis Flux Experiment (INFLUX) 期刊论文
ATMOSPHERIC CHEMISTRY AND PHYSICS, 2020, 20 (7) : 4545-4559
作者:  Balashov, Nikolay, V;  Davis, Kenneth J.;  Miles, Natasha L.;  Lauvaux, Thomas;  Richardson, Scott J.;  Barkley, Zachary R.;  Bonin, Timothy A.
收藏  |  浏览/下载:9/0  |  提交时间:2020/05/13
The projected timing of abrupt ecological disruption from climate change 期刊论文
NATURE, 2020, 580 (7804) : 496-+
作者:  Gorgulla, Christoph;  Boeszoermenyi, Andras;  Wang, Zi-Fu;  Fischer, Patrick D.;  Coote, Paul W.;  Padmanabha Das, Krishna M.;  Malets, Yehor S.;  Radchenko, Dmytro S.;  Moroz, Yurii S.;  Scott, David A.;  Fackeldey, Konstantin;  Hoffmann, Moritz;  Iavniuk, Iryna;  Wagner, Gerhard;  Arthanari, Haribabu
收藏  |  浏览/下载:56/0  |  提交时间:2020/05/13

As anthropogenic climate change continues the risks to biodiversity will increase over time, with future projections indicating that a potentially catastrophic loss of global biodiversity is on the horizon(1-3). However, our understanding of when and how abruptly this climate-driven disruption of biodiversity will occur is limited because biodiversity forecasts typically focus on individual snapshots of the future. Here we use annual projections (from 1850 to 2100) of temperature and precipitation across the ranges of more than 30,000 marine and terrestrial species to estimate the timing of their exposure to potentially dangerous climate conditions. We project that future disruption of ecological assemblages as a result of climate change will be abrupt, because within any given ecological assemblage the exposure of most species to climate conditions beyond their realized niche limits occurs almost simultaneously. Under a high-emissions scenario (representative concentration pathway (RCP) 8.5), such abrupt exposure events begin before 2030 in tropical oceans and spread to tropical forests and higher latitudes by 2050. If global warming is kept below 2 degrees C, less than 2% of assemblages globally are projected to undergo abrupt exposure events of more than 20% of their constituent species  however, the risk accelerates with the magnitude of warming, threatening 15% of assemblages at 4 degrees C, with similar levels of risk in protected and unprotected areas. These results highlight the impending risk of sudden and severe biodiversity losses from climate change and provide a framework for predicting both when and where these events may occur.


Using annual projections of temperature and precipitation to estimate when species will be exposed to potentially harmful climate conditions reveals that disruption of ecological assemblages as a result of climate change will be abrupt and could start as early as the current decade.


  
Pharmacologic fibroblast reprogramming into photoreceptors restores vision 期刊论文
NATURE, 2020, 581 (7806) : 83-+
作者:  Jiang, Mingkai;  Medlyn, Belinda E.;  Drake, John E.;  Duursma, Remko A.;  Anderson, Ian C.;  Barton, Craig V. M.;  Boer, Matthias M.;  Carrillo, Yolima;  Castaneda-Gomez, Laura;  Collins, Luke;  Crous, Kristine Y.;  De Kauwe, Martin G.;  dos Santos, Bruna M.;  Emmerson, Kathryn M.;  Facey, Sarah L.;  Gherlenda, Andrew N.;  Gimeno, Teresa E.;  Hasegawa, Shun;  Johnson, Scott N.;  Kannaste, Astrid;  Macdonald, Catriona A.;  Mahmud, Kashif;  Moore, Ben D.;  Nazaries, Loic;  Neilson, Elizabeth H. J.;  Nielsen, Uffe N.;  Niinemets, Ulo;  Noh, Nam Jin;  Ochoa-Hueso, Raul;  Pathare, Varsha S.;  Pendall, Elise;  Pihlblad, Johanna;  Pineiro, Juan;  Powell, Jeff R.;  Power, Sally A.;  Reich, Peter B.;  Renchon, Alexandre A.;  Riegler, Markus;  Rinnan, Riikka;  Rymer, Paul D.;  Salomon, Roberto L.;  Singh, Brajesh K.;  Smith, Benjamin;  Tjoelker, Mark G.;  Walker, Jennifer K. M.;  Wujeska-Klause, Agnieszka;  Yang, Jinyan;  Zaehle, Soenke;  Ellsworth, David S.
收藏  |  浏览/下载:46/0  |  提交时间:2020/07/03

Photoreceptor loss is the final common endpoint in most retinopathies that lead to irreversible blindness, and there are no effective treatments to restore vision(1,2). Chemical reprogramming of fibroblasts offers an opportunity to reverse vision loss  however, the generation of sensory neuronal subtypes such as photoreceptors remains a challenge. Here we report that the administration of a set of five small molecules can chemically induce the transformation of fibroblasts into rod photoreceptor-like cells. The transplantation of these chemically induced photoreceptor-like cells (CiPCs) into the subretinal space of rod degeneration mice (homozygous for rd1, also known as Pde6b) leads to partial restoration of the pupil reflex and visual function. We show that mitonuclear communication is a key determining factor for the reprogramming of fibroblasts into CiPCs. Specifically, treatment with these five compounds leads to the translocation of AXIN2 to the mitochondria, which results in the production of reactive oxygen species, the activation of NF-kappa B and the upregulation of Ascl1. We anticipate that CiPCs could have therapeutic potential for restoring vision.


A set of five small molecules can induce the transformation of fibroblasts into rod photoreceptor-like cells, which can partially restore pupil reflex and visual function when transplanted into a rod degeneration mouse model.


  
Multiple early-formed water reservoirs in the interior of Mars 期刊论文
NATURE GEOSCIENCE, 2020, 13 (4) : 260-+
作者:  Barnes, Jessica J.;  McCubbin, Francis M.;  Santos, Alison R.;  Day, James M. D.;  Boyce, Jeremy W.;  Schwenzer, Susanne P.;  Ott, Ulrich;  Franchi, Ian A.;  Messenger, Scott;  Anand, Mahesh;  Agee, Carl B.
收藏  |  浏览/下载:6/0  |  提交时间:2020/05/13
The stepwise assembly of the neonatal virome is modulated by breastfeeding 期刊论文
NATURE, 2020
作者:  Medina, Christopher B.;  Mehrotra, Parul;  Arandjelovic, Sanja;  Perrys, Justin S. A.;  Guo, Yizhan;  Morioka, Sho;  Barron, Brady;  Walk, Scott F.;  Ghesquiere, Bart;  Lorenz, Ulrike;  Krupnick, Alexander S.;  Ravichandran, Kodi S.
收藏  |  浏览/下载:36/0  |  提交时间:2020/07/03

The infant gut is colonized first by temperate bacteriophages induced from pioneer bacteria and later by viruses that replicate in human cells, the populations of which are modulated by breastfeeding.


The gut of healthy human neonates is usually devoid of viruses at birth, but quickly becomes colonized, which-in some cases-leads to gastrointestinal disorders(1-4). Here we show that the assembly of the viral community in neonates takes place in distinct steps. Fluorescent staining of virus-like particles purified from infant meconium or early stool samples shows few or no particles, but by one month of life particle numbers increase to 10(9) per gram, and these numbers seem to persist throughout life(5-7). We investigated the origin of these viral populations using shotgun metagenomic sequencing of virus-enriched preparations and whole microbial communities, followed by targeted microbiological analyses. Results indicate that, early after birth, pioneer bacteria colonize the infant gut and by one month prophages induced from these bacteria provide the predominant population of virus-like particles. By four months of life, identifiable viruses that replicate in human cells become more prominent. Multiple human viruses were more abundant in stool samples from babies who were exclusively fed on formula milk compared with those fed partially or fully on breast milk, paralleling reports that breast milk can be protective against viral infections(8-10). Bacteriophage populations also differed depending on whether or not the infant was breastfed. We show that the colonization of the infant gut is stepwise, first mainly by temperate bacteriophages induced from pioneer bacteria, and later by viruses that replicate in human cells  this second phase is modulated by breastfeeding.


  
Operation of a silicon quantum processor unit cell above one kelvin 期刊论文
NATURE, 2020, 580 (7803) : 350-+
作者:  Han, Kyuho;  Pierce, Sarah E.;  Li, Amy;  Spees, Kaitlyn;  Anderson, Grace R.;  Seoane, Jose A.;  Lo, Yuan-Hung;  Dubreuil, Michael;  Olivas, Micah;  Kamber, Roarke A.;  Wainberg, Michael;  Kostyrko, Kaja;  Kelly, Marcus R.;  Yousefi, Maryam;  Simpkins, Scott W.;  Yao, David
收藏  |  浏览/下载:8/0  |  提交时间:2020/07/03

Quantum computers are expected to outperform conventional computers in several important applications, from molecular simulation to search algorithms, once they can be scaled up to large numbers-typically millions-of quantum bits (qubits)(1-3). For most solid-state qubit technologies-for example, those using superconducting circuits or semiconductor spins-scaling poses a considerable challenge because every additional qubit increases the heat generated, whereas the cooling power of dilution refrigerators is severely limited at their operating temperature (less than 100 millikelvin)(4-6). Here we demonstrate the operation of a scalable silicon quantum processor unit cell comprising two qubits confined to quantum dots at about 1.5 kelvin. We achieve this by isolating the quantum dots from the electron reservoir, and then initializing and reading the qubits solely via tunnelling of electrons between the two quantum dots(7-9). We coherently control the qubits using electrically driven spin resonance(10,11) in isotopically enriched silicon(12 28)Si, attaining single-qubit gate fidelities of 98.6 per cent and a coherence time of 2 microseconds during '  hot'  operation, comparable to those of spin qubits in natural silicon at millikelvin temperatures(13-16). Furthermore, we show that the unit cell can be operated at magnetic fields as low as 0.1 tesla, corresponding to a qubit control frequency of 3.5 gigahertz, where the qubit energy is well below the thermal energy. The unit cell constitutes the core building block of a full-scale silicon quantum computer and satisfies layout constraints required by error-correction architectures(8),(17). Our work indicates that a spin-based quantum computer could be operated at increased temperatures in a simple pumped He-4 system (which provides cooling power orders of magnitude higher than that of dilution refrigerators), thus potentially enabling the integration of classical control electronics with the qubit array(18,19).