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《自然》(20201126出书)一周论文导读“鸭脖app官网”
长三角城市协同联动一体化保护生态‘鸭脖app官网下载入口’ 一图一故事——“守株待兔”获铁证:鸭脖app官网

发布时间:2021-11-11    点击量:

本文摘要:编译|冯维维Nature, 26 November 2020, Volume 587 Issue 7835《自然》2020年11月26日,第587卷,7835期天体物理学与量子物理学AstroPhysics & Quantum physicExperimental evidence of neutrinos produced in the CNO fusion cycle in the Sun太阳CNO聚变循环可发生中微子▲ 作者:The Borexino Collaboration▲ 链接:https://www.nature.com/articles/s41586-020-2934-0▲ 摘要在恒星存在的大部门时间里,它们都是由氢聚变为氦所驱动的。

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编译|冯维维Nature, 26 November 2020, Volume 587 Issue 7835《自然》2020年11月26日,第587卷,7835期天体物理学与量子物理学AstroPhysics & Quantum physicExperimental evidence of neutrinos produced in the CNO fusion cycle in the Sun太阳CNO聚变循环可发生中微子▲ 作者:The Borexino Collaboration▲ 链接:https://www.nature.com/articles/s41586-020-2934-0▲ 摘要在恒星存在的大部门时间里,它们都是由氢聚变为氦所驱动的。聚变通过两个历程举行:质子-质子(pp)链和碳-氮-氧(CNO)循环。

作者陈诉了在太阳CNO周期中发生的中微子的直接观察,具有很高的统计意义。这一实验证据是使用Borexino的高放射性、大要积液体闪烁体探测器获得的,该实验位于意大利国家核物理研究所格兰萨索国家实验室。在CNO循环中,氢的聚变是由碳、氮和氧催化的,所以它的速率——以及释放的CNO中微子的通量——直接取决于太阳焦点中这些元素的品貌。

这个效果为使用CNO中微子直接丈量太阳的金属品貌铺平了门路。作者表现,这一发现量化了太阳中CNO聚变的相对孝敬,约为1%;在大质量恒星中,这是发生能量的主要历程。这项研究为宇宙中恒星从氢转化为氦的主要机制提供了实验证据。▲ AbstractFor most of their existence, stars are fuelled by the fusion of hydrogen into helium. Fusion proceeds via two processes that are well understood theoretically: the proton–proton (pp) chain and the carbon–nitrogen–oxygen (CNO) cycle. Here we report the direct observation, with a high statistical significance, of neutrinos produced in the CNO cycle in the Sun. This experimental evidence was obtained using the highly radiopure, large-volume, liquid-scintillator detector of Borexino, an experiment located at the underground Laboratori Nazionali del Gran Sasso in Italy. The main experimental challenge was to identify the excess signal—only a few counts per day above the background per 100 tonnes of target—that is attributed to interactions of the CNO neutrinos. Advances in the thermal stabilization of the detector over the last five years enabled us to develop a method to constrain the rate of bismuth-210 contaminating the scintillator. In the CNO cycle, the fusion of hydrogen is catalysed by carbon, nitrogen and oxygen, and so its rate—as well as the flux of emitted CNO neutrinos—depends directly on the abundance of these elements in the solar core. This result therefore paves the way towards a direct measurement of the solar metallicity using CNO neutrinos. Our findings quantify the relative contribution of CNO fusion in the Sun to be of the order of 1 per cent; however, in massive stars, this is the dominant process of energy production. This work provides experimental evidence of the primary mechanism for the stellar conversion of hydrogen into helium in the Universe.博瑞西诺不锈钢球体育太阳的艺术合成照 图源:Maxim Gromov和博瑞西诺互助组织Observing the emergence of a quantum phase transition shell by shell一层层地视察量子相变的泛起▲ 作者:Luca Bayha, Marvin Holten, Ralf Klemt, Keerthan Subramanian, Johannes Bjerlin, Stephanie M. Reimann, Georg M. Bruun, Philipp M. Preiss & Selim Jochim▲ 链接:https://www.nature.com/articles/s41586-020-2936-y▲ 摘要多体物理学形貌了仅通过视察一个系统的组成部门而不能明白的现象。

突出的例子有对称性破坏、相变和团体引发。作者视察到量子相变从正常相过渡到超流体相的少体前兆。这种转变是由与振幅振动相关的阶参量模态的软化信号发出的,通常被称为希格斯模式。作者实现了对局限于二维谐波势的超低温费米子的精致控制,并在基态下制备了2、6和12个费米子原子的闭壳结构,具有高保真度。

使用全原子计数统计,作者找到了仅由相干引发对组成的最低共振。这个多体引发的奇特的非单调的相互作用依赖,联合与数值盘算的比力,使我们可以确定它是希格斯模式的前兆。作者表现,其原子模拟器提供了一个方法来一个粒子一个粒子地研究团体现象的泛起和热力学极限。

▲ AbstractMany-body physics describes phenomena that cannot be understood by looking only at the constituents of a system. Striking examples are broken symmetry, phase transitions and collective excitations. Here we observe the few-body precursor of a quantum phase transition from a normal to a superfluid phase. The transition is signalled by the softening of the mode associated with amplitude vibrations of the order parameter, usually referred to as a Higgs mode. We achieve fine control over ultracold fermions confined to two-dimensional harmonic potentials and prepare closed-shell configurations of 2, 6 and 12 fermionic atoms in the ground state with high fidelity. Using full atom counting statistics, we find the lowest resonance to consist of coherently excited pairs only. The distinct non-monotonic interaction dependence of this many-body excitation, combined with comparison with numerical calculations allows us to identify it as the precursor of the Higgs mode. Our atomic simulator provides a way to study the emergence of collective phenomena and the thermodynamic limit, particle by particle.纳米技术Nano-TechSpin-enhanced nanodiamond biosensing for ultrasensitive diagnostics超敏捷纳米金刚石生物传感有助改善疾病早期诊断▲ 作者:Benjamin S. Miller, Léonard Bezinge, Harriet D. Gliddon, Da Huang, Gavin Dold, Eleanor R. Gray, Judith Heaney, Peter J. Dobson, Eleni Nastouli, John J. L. Morton & Rachel A. McKendry▲ 链接:https://www.nature.com/articles/s41586-020-2917-1▲ 摘要金刚石中氮空位缺陷的量子自旋特性使其在量子盘算和通信领域有广泛应用。作者使用微波场调制发射强度和频域分析分散配景自荧光信号,研究了作为一种体外诊断的超敏捷的标签——荧光纳米金刚石。以广泛使用的低成本横向流模式为例,作者对生物素-亲和素模型的检出限为8.2×10−19 摩尔,比使用金纳米颗粒的检出限敏捷105倍。

通过增加10分钟的等温扩增步骤,可以实现对HIV-1 RNA的单拷贝检测,并通过带有提取步骤的临床血浆样本进一步验证。这种超敏捷的量子诊断平台适用于多种诊断测试花样和疾病,并有潜力改变疾病的早期诊断,以造福患者和人群。▲ AbstractThe quantum spin properties of nitrogen-vacancy defects in diamond enable diverse applications in quantum computing and communications. Here we investigate fluorescent nanodiamonds as an ultrasensitive label for in vitro diagnostics, using a microwave field to modulate emission intensity and frequency-domain analysis to separate the signal from background autofluorescence. Focusing on the widely used, low-cost lateral flow format as an exemplar, we achieve a detection limit of 8.2 × 10−19 molar for a biotin–avidin model, 105 times more sensitive than that obtained using gold nanoparticles. Single-copy detection of HIV-1 RNA can be achieved with the addition of a 10-minute isothermal amplification step, and is further demonstrated using a clinical plasma sample with an extraction step. This ultrasensitive quantum diagnostics platform is applicable to numerous diagnostic test formats and diseases, and has the potential to transform early diagnosis of disease for the benefit of patients and populations.Lanthanide-doped inorganic nanoparticles turn molecular triplet excitons bright掺镧的无机纳米粒子使分子的三态激子变亮▲ 作者:Sanyang Han, Renren Deng, Qifei Gu, Limeng Ni, Uyen Huynh, Jiangbin Zhang, Zhigao Yi, Baodan Zhao, Hiroyuki Tamura, Anton Pershin, Hui Xu, Zhiyuan Huang, Shahab Ahmad, Mojtaba Abdi-Jalebi, Aditya Sadhanala, Ming Lee Tang, Artem Bakulin, David Beljonne, Xiaogang Liu & Akshay Rao▲ 链接:https://www.nature.com/articles/s41586-020-2932-2▲ 摘要三态激子的发生、控制和转移,由于其在固相和固相体系中的寿命和扩散长度,以及在光发射、光电子学、光子变频和光催化等方面的应用,引起了人们的广泛关注。

作者证明晰通过耦合有机分子和掺镧的无机绝缘纳米颗粒来控制三重态动力学是可能的。这使得经典克制的从基态单态到引发态三联体的跃迁可以获得振子强度,使三联体可以通过光子吸收直接在分子上发生。

光生单态激子可以通过系统间交织在亚10皮秒的时间尺度上转化为三态激子。这些效果为控制三态激子提供了一种新的方法,对许多光电和生物医学领域的研究具有重要意义。

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▲ AbstractThe generation, control and transfer of triplet excitons in molecular and hybrid systems is of great interest owing to their long lifetime and diffusion length in both solid-state and solution phase systems, and to their applications in light emission, optoelectronics, photon frequency conversion and photocatalysis. Here we demonstrate that it is possible to control triplet dynamics by coupling organic molecules to lanthanide-doped inorganic insulating nanoparticles. This allows the classically forbidden transitions from the ground-state singlet to excited-state triplets to gain oscillator strength, enabling triplets to be directly generated on molecules via photon absorption. Photogenerated singlet excitons can be converted to triplet excitons on sub-10-picosecond timescales with unity efficiency by intersystem crossing. These results provide a new way to control triplet excitons, which is essential for many fields of optoelectronic and biomedical research.气候与生态Climate & EcologyAntarctic ice dynamics amplified by Northern Hemisphere sea-level forcing北半球海平面迫使南极冰动态放大▲ 作者:Natalya Gomez, Michael E. Weber, Peter U. Clark, Jerry X. Mitrovica & Holly K. Han▲ 链接:https://www.nature.com/articles/s41586-020-2916-2▲ 摘要由于日晒和温室气体的强迫作用,北半球冰层融化导致的海平面上升导致了南极冰盖(AIS)海洋部门的基线退却。作者将一个冰原模型和一个全球海平面模型相联合,展示了AIS的动态被北半球的海平面强迫放大。由于这种半球间的相互作用,北半球海平面的一个大的或快速的强迫作用,增强了冰川期间的基线推进和AIS的相关质量增加,以及在冰川消退期间的基线退却和质量损失。相对没有这些交互的模型,在作者的模型中加入北半球的海平面强迫增加了最后一次冰河时期(约2.6万年~2万年前)AIS的体积,引发了更早的基线退却,并导致贯串最后一次冰川消退的千年尺度的变化。

这些发现与最后一次冰川最大期和随后冰盖消退期间AIS规模的地质重建以及南极洲海平面的相对变化一致。▲ AbstractSea-level rise due to ice loss in the Northern Hemisphere in response to insolation and greenhouse gas forcing is thought to have caused grounding-line retreat of marine-based sectors of the Antarctic Ice Sheet (AIS). Here, using an ice-sheet model coupled to a global sea-level model, we show that AIS dynamics are amplified by Northern Hemisphere sea-level forcing. As a result of this interhemispheric interaction, a large or rapid Northern Hemisphere sea-level forcing enhances grounding-line advance and associated mass gain of the AIS during glaciation, and grounding-line retreat and mass loss during deglaciation. Relative to models without these interactions, the inclusion of Northern Hemisphere sea-level forcing in our model increases the volume of the AIS during the Last Glacial Maximum (about 26,000 to 20,000 years ago), triggers an earlier retreat of the grounding line and leads to millennial-scale variability throughout the last deglaciation. These findings are consistent with geologic reconstructions of the extent of the AIS during the Last Glacial Maximum and subsequent ice-sheet retreat, and with relative sea-level change in Antarctica.Sensory pollutants alter bird phenology and fitness across a continent光和噪音改变大陆鸟类物候和适应性▲ 作者:Masayuki Senzaki, Jesse R. Barber, Jennifer N. Phillips, Neil H. Carter, Caren B. Cooper, Mark A. Ditmer, Kurt M. Fristrup, Christopher J. W. McClure, Daniel J. Mennitt, Luke P. Tyrrell, Jelena Vukomanovic, Ashley A. Wilson & Clinton D. Francis▲ 链接:https://www.nature.com/articles/s41586-020-2903-7▲ 摘要人类噪声和夜间照明在地球规模内的扩展已成为日益关注的环保问题。作者使用一个大型的公民科学数据集与来自美国各地的高分辨率噪音和光数据配对,来评估这些刺激如何影响142种鸟类的繁殖乐成。

作者发现,对感官污染物的反映与物种的功效特征和栖息地关系有关。此外,物种眼睛聚光能力的增强与在对光的反映中繁殖时间的提高有关,这可能造成物候的不匹配。出人意料的是,更好的聚光能力与淘汰离合器故障和提高整体巢穴对光照的反映乐成率有关,这就提出了重要的问题,即对感官污染物的反映如何抵消或加剧对全球变化的其他方面的反映,如气候变暖。

这些发现讲明,人为的噪音和光线会极大地影响繁殖鸟类的物候和适应性,并强调了在掩护生物多样性的传统情况维度之外还要思量感官污染物的须要性。▲ AbstractExpansion of anthropogenic noise and night lighting across our planet1,2 is of increasing conservation concern. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. Additionally, increased light-gathering ability of species’ eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches7. Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation.光污染袒露增加时,西蓝鸲会产更多卵、产卵阶段失败率降低且整体繁殖乐成率会上升。图源:David Keeling。


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