Abstract：
:Knowledge of the composition of the Earth's core is important for understanding its melting point and therefore the temperature at the inner-core boundary and the temperature profile of the core and mantle. In addition, the partitioning of light elements between solid and liquid, as the outer core freezes at the inner-core boundary, is believed to drive compositional convection, which in turn generates the Earth's magnetic field. It is generally accepted that the liquid outer core and the solid inner core consist mainly of iron. The outer core, however, is also thought to contain a significant fraction of light elements, because its density--as deduced from seismological data and other measurements--is 6-10 per cent less than that estimated for pure liquid iron. Similar evidence indicates a smaller but still appreciable fraction of light elements in the inner core. The leading candidates for the light elements present in the core are sulphur, oxygen and silicon. Here we obtain a constraint on core composition derived from ab initio calculation of the chemical potentials of light elements dissolved in solid and liquid iron. We present results for the case of sulphur, which provide strong evidence against the proposal that the outer core is close to being a binary iron-sulphur mixture.
journal_name
Naturejournal_title
Natureauthors
Alfe D,Gillan MJ,Price GDdoi
10.1038/35012056keywords:
subject
Has Abstractpub_date
2000-05-11 00:00:00pages
172-5issue
6783eissn
0028-0836issn
1476-4687journal_volume
405pub_type
杂志文章相关文献
NATURE文献大全abstract：:The National Institutes of Health's Recombinant DNA Advisory Committee (RAC) has approved a commercial proposal by Advanced Genetic Sciences Inc. to field-test recombinant ice-nucleating bacteria. Its decision came two weeks after a federal judge halted a similar trial by researchers from the University of California...
journal_title：Nature
pub_type： 新闻
doi：10.1038/309483a0
更新日期：1984-06-07 00:00:00
abstract：:'Hot Jupiter' extrasolar planets are expected to be tidally locked because they are close (<0.05 astronomical units, where 1 au is the average Sun-Earth distance) to their parent stars, resulting in permanent daysides and nightsides. By observing systems where the planet and star periodically eclipse each other, sever...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature05782
更新日期：2007-05-10 00:00:00
abstract：:Coherent light sources can be used to manipulate the outcome of light-matter interactions by exploiting interference phenomena in the time and frequency domain. A powerful tool in this emerging field of 'quantum control' is the adaptive shaping of femtosecond laser pulses, resulting, for instance, in selective molecul...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35102037
更新日期：2001-11-01 00:00:00
abstract：:Intracellular responses recorded in vitro from the cochleas of anaesthetized mammals have shown that the mechanoreceptive inner and outer hair cells are sharply tuned, accounting for many of the properties of the afferent fibres in the auditory nerve. However, in vivo it has not been possible to measure directly the e...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/321517a0
更新日期：1986-05-29 00:00:00
abstract：:The population vector hypothesis was introduced almost twenty years ago to illustrate that a population vector constructed from neural activity in primary motor cortex (MI) of non-human primates could predict the direction of hand movement during reaching. Alternative explanations for this population signal have been ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35093102
更新日期：2001-09-13 00:00:00
abstract：:Retrospective epidemiological data have indicated that cutaneous malignant melanoma may arise as a consequence of intense, intermittent exposure of the skin to ultraviolet radiation, particularly in children, rather than from the cumulative lifetime exposure that is associated with other forms of skin cancer. Here we ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35095108
更新日期：2001-09-20 00:00:00
abstract：:We have used in vitro mutagenesis to identify a DNA sequence that is required for glucose regulation of the ADR2 locus of Saccharomyces cerevisiae. This region, located between 200 and 1,000 base pairs upstream of the structural gene for ADH II, has been identified by genetic and biochemical analysis as the site of AD...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/300724a0
更新日期：1982-12-23 00:00:00
abstract：:The T-cell immune response is directed against antigenic peptide fragments generated in intracellular compartments, the cytosol or the endocytic system. Peptides derived from cytosolic proteins, usually of biosynthetic origin, are presented efficiently to T-cell receptors by major histocompatibility complex (MHC) clas...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/348738a0
更新日期：1990-12-20 00:00:00
abstract：:The repressor of phage 434 binds to six operator sites on the phage chromosome. A comparison of the sequences of these 14-base-pair (bp) operator sites reveals a striking pattern: at five of the six sites, the symmetrically arrayed outer eight base pairs (four in each half-site) are identical and the remaining site di...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/326886a0
更新日期：1987-04-30 00:00:00
abstract：:Highly correlated electronic systems--such as transition-metal oxides that are doped Mott insulators--are complex systems which exhibit puzzling phenomena, including high-temperature superconductivity and colossal magnetoresistivity. Recent studies suggest that in such systems collective electronic phenomena are impor...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35021018
更新日期：2000-08-17 00:00:00
abstract：:Generalization is a cognitive ability that allows similar stimuli along a given dimension to be treated as equivalents. Insects exhibit high levels of visual generalization. Honeybees trained to recognize complex visual stimuli on the basis of a single feature generalize their choice to novel stimuli sharing that comm...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature02594
更新日期：2004-06-17 00:00:00
abstract：:The terrestrial sediment record indicates that the Earth's climate varied drastically in the Precambrian era (before 550 million years ago), ranging from surface temperatures similar to or higher than today's to global glaciation events. The most continuous record of sea surface temperatures of that time has been deri...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/nature05239
更新日期：2006-10-26 00:00:00
abstract：:The sensitivity of soil carbon to warming is a major uncertainty in projections of carbon dioxide concentration and climate. Experimental studies overwhelmingly indicate increased soil organic carbon (SOC) decomposition at higher temperatures, resulting in increased carbon dioxide emissions from soils. However, recent...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature03226
更新日期：2005-01-20 00:00:00
abstract：:Although directed migration is a feature of both individual cells and cell groups, guided migration has been studied most extensively for single cells in simple environments. Collective guidance of cell groups remains poorly understood, despite its relevance for development and metastasis. Neural crest cells and neuro...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature05965
更新日期：2007-07-19 00:00:00
abstract：:The thymus is the major, if not the sole site of maturation of T lymphocytes from their haematopoietic precursors. During embryonic life (at a few well-defined intervals, at least in birds) the thymus receives thymus-homing haematopoietic precursors that give rise to antigen-specific functional T lymphocytes. Although...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/309629a0
更新日期：1984-06-14 00:00:00
abstract：:The use of chemotherapy to suppress replication of the human immunodeficiency virus (HIV) has transformed the face of AIDS in the developed world. Pronounced reductions in illness and death have been achieved and healthcare utilization has diminished. HIV therapy has also provided many new insights into the pathogenes...
journal_title：Nature
pub_type： 杂志文章,评审
doi：10.1038/35073673
更新日期：2001-04-19 00:00:00
abstract：:Oncogenic mutations in the serine/threonine kinase B-RAF (also known as BRAF) are found in 50-70% of malignant melanomas. Pre-clinical studies have demonstrated that the B-RAF(V600E) mutation predicts a dependency on the mitogen-activated protein kinase (MAPK) signalling cascade in melanoma-an observation that has bee...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature09627
更新日期：2010-12-16 00:00:00
abstract：:Immunization of male and female animals with extracts of whole sperm cells is known to cause infertility. Also, men and women who spontaneously produce antisperm antibodies are infertile but otherwise healthy. Although the critical sperm antigens are unknown, these observations have led to the proposal that sperm prot...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/335543a0
更新日期：1988-10-06 00:00:00
abstract：:Topoisomerases are expressed throughout the developing and adult brain and are mutated in some individuals with autism spectrum disorder (ASD). However, how topoisomerases are mechanistically connected to ASD is unknown. Here we find that topotecan, a topoisomerase 1 (TOP1) inhibitor, dose-dependently reduces the expr...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature12504
更新日期：2013-09-05 00:00:00
abstract：:The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fa...
journal_title：Nature
pub_type： 历史文章,杂志文章
doi：10.1038/nature00879
更新日期：2002-07-11 00:00:00
abstract：:Nanoscale electronic devices made from carbon nanotubes, such as transistors and sensors, are much smaller and more versatile than those that rely on conventional microelectronic chips, but their development for mass production has been thwarted by difficulties in aligning and integrating the millions of nanotubes req...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/425036a
更新日期：2003-09-04 00:00:00
abstract：:Eukaryotic cells seem to use GTP hydrolysis to regulate vesicular traffic in exocytosis and endocytosis. The best evidence for this comes from studies on the yeast Saccharomyces cerevisiae that have identified two small Ras-related GTP-binding proteins, Sec4p and Ypt1p, which control distinct stages of the secretory p...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/345553a0
更新日期：1990-06-07 00:00:00
abstract：:Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis largely owing to inefficient diagnosis and tenacious drug resistance. Activation of pancreatic stellate cells (PSCs) and consequent development of dense stroma are prominent features accounting for this aggressive biology1,2. The reciprocal interplay betwe...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/s41586-019-1130-6
更新日期：2019-05-01 00:00:00
abstract：:In the HTML version of this Letter, the affiliations for authors Andrew S. Azman, Dhirendra Kumar and Thandavarayan Ramamurthy were inverted (the PDF and print versions of the Letter were correct); the affiliations have been corrected online. ...
journal_title：Nature
pub_type： 杂志文章,已发布勘误
doi：10.1038/s41586-019-0966-0
更新日期：2019-02-01 00:00:00
abstract：:Established infections with the human and simian immunodeficiency viruses (HIV and SIV, respectively) are thought to be permanent with even the most effective immune responses and antiretroviral therapies only able to control, but not clear, these infections. Whether the residual virus that maintains these infections ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature12519
更新日期：2013-10-03 00:00:00
abstract：: ...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/d41586-019-00219-5
更新日期：2019-01-01 00:00:00
abstract：:The loose material--regolith--on the surfaces of asteroids is thought to represent ballistically emplaced ejecta from impacts but the identification of source craters and the detailed study of the regolith modification have been hampered by the limited spatial resolution and area coverage of the few asteroids imaged b...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/35096513
更新日期：2001-09-27 00:00:00
abstract：:Although the link between long gamma-ray bursts (GRBs) and supernovae has been established, hitherto there have been no observations of the beginning of a supernova explosion and its intimate link to a GRB. In particular, we do not know how the jet that defines a gamma-ray burst emerges from the star's surface, nor ho...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature04892
更新日期：2006-08-31 00:00:00
abstract：:Many collective human activities, including violence, have been shown to exhibit universal patterns. The size distributions of casualties both in whole wars from 1816 to 1980 and terrorist attacks have separately been shown to follow approximate power-law distributions. However, the possibility of universal patterns r...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/nature08631
更新日期：2009-12-17 00:00:00
abstract：:The formation of disulphide bonds is essential to the structure and function of proteins. These bonds rapidly form either cotranslationally or immediately post-translationally in the lumen of the endoplasmic reticulum. Native disulphide pairing for such proteins has been achieved in vitro; however, the rates of reasse...
journal_title：Nature
pub_type： 杂志文章
doi：10.1038/317267a0
更新日期：1985-09-19 00:00:00
