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Diamonds engage both optical microscopy and MRI for better imaging 新闻
来源平台：EurekAlert. 发布日期：2021
作者:  admin
收藏  |  浏览/下载：26/0  |  提交时间：2021/05/21
Probing wet fire smoke in clouds: can water intensify the earth's warming? 新闻
来源平台：EurekAlert. 发布日期：2021
作者:  admin
收藏  |  浏览/下载：2/0  |  提交时间：2021/04/06
Exploring the world’s largest ocean current 新闻
来源平台：CNRS News. 发布日期：2021
作者:  admin
收藏  |  浏览/下载：12/0  |  提交时间：2021/01/28
Study reveals jellyfish create a 'virtual wall' to enhance performance 新闻
来源平台：EurekAlert. 发布日期：2021
作者:  admin
收藏  |  浏览/下载：7/0  |  提交时间：2021/01/15
Using light's properties to indirectly see inside a cell membrane 新闻
来源平台：EurekAlert. 发布日期：2020
作者:  admin
收藏  |  浏览/下载：0/0  |  提交时间：2020/08/28
The Nd-142/Nd-144 variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (26) : 14738-14744
作者:  Hyung, Eugenia;  Jacobsen, Stein B.
收藏  |  浏览/下载：6/0  |  提交时间：2020/06/22
Estimating US fossil fuel CO2 emissions from measurements of C-14 in atmospheric CO2 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (24) : 13300-13307
作者:  Basu, Sourish;  Lehman, Scott J.;  Miller, John B.;  Andrews, Arlyn E.;  Sweeney, Colm;  Gurney, Kevin R.;  Xu, Xiaomei;  Southon, John;  Tans, Pieter P.
收藏  |  浏览/下载：14/0  |  提交时间：2020/06/09
fossil fuel CO2  radiocarbon  atmospheric inverse modeling  
Early detection of Alzheimer's disease with dynamic MRI measurement of glucose in brain 新闻
来源平台：EurekAlert. 发布日期：2020
作者:  admin
收藏  |  浏览/下载：0/0  |  提交时间：2020/05/15
Depth-dependent soil mixing persists across climate zones 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (16) : 8750-8756
作者:  Gray, Harrison J.;  Keen-Zebert, Amanda;  Furbish, David J.;  Tucker, Gregory E.;  Mahan, Shannon A.
收藏  |  浏览/下载：5/0  |  提交时间：2020/05/13
soil mixing  luminescence  OSL  sediment tracing  pedoturbation  
Hydrothermal (NN)-N-15-N-15 abundances constrain the origins of mantle nitrogen 期刊论文
NATURE, 2020, 580 (7803) : 367-+
作者:  Zhao, Steven;  Jang, Cholsoon;  Liu, Joyce;  Uehara, Kahealani;  Gilbert, Michael;  Izzo, Luke;  Zeng, Xianfeng;  Trefely, Sophie;  Fernandez, Sully;  Carrer, Alessandro;  Miller, Katelyn D.;  Schug, Zachary T.;  Snyder, Nathaniel W.;  Gade, Terence P.;  Titchenell, Paul M.;  Rabinowitz, Joshua D.;  Wellen, Kathryn E.
收藏  |  浏览/下载：14/0  |  提交时间：2020/05/13

Nitrogen is the main constituent of the Earth'  s atmosphere, but its provenance in the Earth'  s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth'  s accretion versus that subducted from the Earth'  s surface is unclear(1-6). Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare (NN)-N-15-N-15 isotopologue of N-2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle delta N-15 (the fractional difference in N-15/N-14 from air), N-2/Ar-36 and N-2/He-3. Our results show that negative delta N-15 values observed in gases, previously regarded as indicating a mantle origin for nitrogen(7-10), in fact represent dominantly air-derived N-2 that experienced N-15/N-14 fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the (NN)-N-15-N-15 data allow extrapolations that characterize mantle endmember delta N-15, N-2/Ar-36 and N-2/He-3 values. We show that the Eifel region has slightly increased delta N-15 and N-2/Ar-36 values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts(11), consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has delta N-15 values substantially greater than that of the convective mantle, resembling surface components(12-15), its N-2/Ar-36 and N-2/He-3 ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume delta N-15 values may both be dominantly primordial features.