Abstract:
:Major ice sheets were permanently established on Antarctica approximately 34 million years ago, close to the Eocene/Oligocene boundary, at the same time as a permanent deepening of the calcite compensation depth in the world's oceans. Until recently, it was thought that Northern Hemisphere glaciation began much later, between 11 and 5 million years ago. This view has been challenged, however, by records of ice rafting at high northern latitudes during the Eocene epoch and by estimates of global ice volume that exceed the storage capacity of Antarctica at the same time as a temporary deepening of the calcite compensation depth approximately 41.6 million years ago. Here we test the hypothesis that large ice sheets were present in both hemispheres approximately 41.6 million years ago using marine sediment records of oxygen and carbon isotope values and of calcium carbonate content from the equatorial Atlantic Ocean. These records allow, at most, an ice budget that can easily be accommodated on Antarctica, indicating that large ice sheets were not present in the Northern Hemisphere. The records also reveal a brief interval shortly before the temporary deepening of the calcite compensation depth during which the calcite compensation depth shoaled, ocean temperatures increased and carbon isotope values decreased in the equatorial Atlantic. The nature of these changes around 41.6 million years ago implies common links, in terms of carbon cycling, with events at the Eocene/Oligocene boundary and with the 'hyperthermals' of the Early Eocene climate optimum. Our findings help to resolve the apparent discrepancy between the geological records of Northern Hemisphere glaciation and model results that indicate that the threshold for continental glaciation was crossed earlier in the Southern Hemisphere than in the Northern Hemisphere.
journal_name
Naturejournal_title
Natureauthors
Edgar KM,Wilson PA,Sexton PF,Suganuma Ydoi
10.1038/nature06053subject
Has Abstractpub_date
2007-08-23 00:00:00pages
908-11issue
7156eissn
0028-0836issn
1476-4687pii
nature06053journal_volume
448pub_type
历史文章,杂志文章相关文献
NATURE文献大全abstract::It is a controversial issue whether 'real' movement, seen from the successive stimulation of retinal receptors by a moving image, and 'apparent' (phi) movement, which is produced by stimuli separated in space and time, are transmitted by the same or different neural channels. With this question in mind, we have devise...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/307729a0
更新日期:1984-02-23 00:00:00
abstract::Anti-inflammatory glucocorticoids inhibit prostaglandin (PG) biosynthesis by preventing arachidonic acid release from phospholipids rather than inhibiting the cyclooxygenase. As in other cells, this steroid action depends on receptor occupation and de novo protein/RNA biosynthesis. We have previously shown in guinea p...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/287147a0
更新日期:1980-09-11 00:00:00
abstract::Government policies currently commit us to surface warming of three to four degrees Celsius above pre-industrial levels by 2100, which will lead to enhanced ice-sheet melt. Ice-sheet discharge was not explicitly included in Coupled Model Intercomparison Project phase 5, so effects on climate from this melt are not cur...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-019-0889-9
更新日期:2019-02-01 00:00:00
abstract::To understand the molecular basis of microtubule-associated motility during mitosis, the mechanochemical factors that generate the relevant motile force must be identified. Myosin, the ATPase that interacts with actin to produce the force for muscle contraction and other forms of cell motility, is believed to be invol...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/318483a0
更新日期:1985-12-05 00:00:00
abstract::Parkinson's disease is characterized by loss of dopamine neurons in the substantia nigra1. Similar to other major neurodegenerative disorders, there are no disease-modifying treatments for Parkinson's disease. While most treatment strategies aim to prevent neuronal loss or protect vulnerable neuronal circuits, a poten...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-020-2388-4
更新日期:2020-06-01 00:00:00
abstract::Mycobacterium tuberculosis (Mtb) is the leading cause of death from infection worldwide1. The only available vaccine, BCG (Bacillus Calmette-Guérin), is given intradermally and has variable efficacy against pulmonary tuberculosis, the major cause of mortality and disease transmission1,2. Here we show that intravenous ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-019-1817-8
更新日期:2020-01-01 00:00:00
abstract::Organic photovoltaic cells are now approaching commercially viable efficiencies, particularly for applications that make use of their unique potential for flexibility and semitransparency1-3. However, their reliability remains a major concern, as even the most stable devices reported so far degrade within only a few y...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-019-1544-1
更新日期:2019-09-01 00:00:00
abstract::Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature06210
更新日期:2007-10-04 00:00:00
abstract::Multistranded DNA structures based upon guanine association have been proposed to be important in the structure of chromosome telomeres and in immunoglobulin class switching. Nucleic acids containing runs of guanine bases form a number of structures in vitro, including fold-back structures (Fig. 1a) and parallel-stran...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/360280a0
更新日期:1992-11-19 00:00:00
abstract::Cells subjected to a heat shock, or a variety of other stresses increase the synthesis of a set of proteins, known as heat shock proteins. This response is apparently universal, occurring in the entire range from bacterial to mammalian cells. In Escherichia coli heat shock protein synthesis transiently increases follo...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/329348a0
更新日期:1987-09-24 00:00:00
abstract::The genetic relationships of human populations have been studied by comparing gene frequency data for protein and blood-group loci of different populations. DNA analysis now promises to be more informative since not only do the DNA coding sequences have more variation than their corresponding proteins but, in addition...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/319491a0
更新日期:1986-02-06 00:00:00
abstract::The ras-related low-molecular-mass GTPases participate in signal transduction involving a variety of cellular functions, including cell-cycle progression, cellular differentiation, cytoskeletal organization, protein transport and secretion. The cycling of these proteins between GTP-bound and GDP-bound states is partia...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/359153a0
更新日期:1992-09-10 00:00:00
abstract::One of us has previously reported that treatment of the Keilin and Hartree heart-muscle preparation with 2,3-dimercaptopropanol (BAL), in the presence of air, leads to the complete inactivation of the succinate oxidase system with little if any effect on the activities of succinate dehydrogenase (until more than half ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/288717a0
更新日期:1980-12-25 00:00:00
abstract::The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis and low cloud formation. But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature06690
更新日期:2008-03-13 00:00:00
abstract::An amendment to this paper has been published and can be accessed via a link at the top of the paper. ...
journal_title:Nature
pub_type: 已发布勘误
doi:10.1038/s41586-020-2351-4
更新日期:2020-06-01 00:00:00
abstract::The site of action of the antispastic drug baclofen has long been considered to reside in the spinal cord although supraspinal effects have also been reported. This beta-chlorophenyl derivative of the neurotransmitter gamma-aminobutyric acid (GABA) depresses both monosynaptic and polysynaptic transmission in the cord ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/307071a0
更新日期:1984-01-05 00:00:00
abstract::External agents of mortality (disturbances) occur over a wide range of scales of space and time, and are believed to have large effects on species diversity. The "intermediate disturbance hypothesis", which proposes maximum diversity at intermediate frequencies of disturbance, has received support from both field and ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35050080
更新日期:2000-12-21 00:00:00
abstract::Molecules capable of mimicking the function of a wide range of mechanical devices have been fabricated, with motors that can induce mechanical movement attracting particular attention. Such molecular motors convert light or chemical energy into directional rotary or linear motion, and are usually prepared and operated...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature04127
更新日期:2005-10-27 00:00:00
abstract::Primordial germ cells (PGCs) are first identifiable as a population of about eight alkaline phosphatase-positive cells in the 7.0 days postcoitum mouse embryo. During the next 6 days of development they proliferate to give rise to the 25,000 cells that will establish the meiotic population. Steel factor is required fo...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/359550a0
更新日期:1992-10-08 00:00:00
abstract::Vaccination has proved a powerful defence against a range of infectious diseases of humans and animals. However, its potential to control major epidemics of foot-and-mouth disease (FMD) in livestock is contentious. Using an individual farm-based model, we consider either national prophylactic vaccination campaigns in ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature01343
更新日期:2003-01-09 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::Humans are able to classify novel items correctly by category; some other animals have also been shown to do this. During category learning, humans group perceptual stimuli by abstracting qualities from similarity relationships of their physical properties. Forming categories is fundamental to cognition and can be ind...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35089076
更新日期:2001-08-16 00:00:00
abstract::Receptors for excitatory amino acids in the mammalian central nervous system are classified into three major subtypes, ones which prefer N-methyl-D-aspartate (NMDA), quisqualate (QA), or kainate (KA) as type agonists respectively. These receptors are considered to mediate fast postsynaptic potentials by activating ion...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/325531a0
更新日期:1987-02-05 00:00:00
abstract::Overfishing of large-bodied benthic fishes and their subsequent population collapses on the Scotian Shelf of Canada's east coast and elsewhere resulted in restructuring of entire food webs now dominated by planktivorous, forage fish species and macroinvertebrates. Despite the imposition of strict management measures i...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10285
更新日期:2011-07-27 00:00:00
abstract::Clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, is characterized by elevated glycogen levels and fat deposition. These consistent metabolic alterations are associated with normoxic stabilization of hypoxia-inducible factors (HIFs) secondary to von Hippel-Lindau (VHL) mutations that occu...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature13557
更新日期:2014-09-11 00:00:00
abstract::The Indian Ocean dipole is a prominent mode of coupled ocean-atmosphere variability, affecting the lives of millions of people in Indian Ocean rim countries. In its positive phase, sea surface temperatures are lower than normal off the Sumatra-Java coast, but higher in the western tropical Indian Ocean. During the ext...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature13327
更新日期:2014-06-12 00:00:00
abstract::An essential feature of the bacterial pathogen Salmonella spp. is its ability to enter cells that are normally non-phagocytic, such as those of the intestinal epithelium. The bacterium achieves entry by delivering effector proteins into the host-cell cytosol by means of a specialized protein-secretion system (termed t...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/45829
更新日期:1999-09-16 00:00:00
abstract::A consequence of relativity is that in the presence of an electric field, the spin and momentum states of an electron can be coupled; this is known as spin-orbit coupling. Such an interaction opens a pathway to the manipulation of electron spins within non-magnetic semiconductors, in the absence of applied magnetic fi...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature02202
更新日期:2004-01-01 00:00:00
abstract::RNA polymerase II (RNAP II) is responsible for transcribing all messenger RNAs in eukaryotic cells during a highly regulated process that is conserved from yeast to human, and that serves as a central control point for cellular function. Here we investigate the transcription dynamics of single RNAP II molecules from S...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature05701
更新日期:2007-04-12 00:00:00
abstract::In metazoans, the Ras-Raf-MEK (mitogen-activated protein-kinase kinase)-ERK (extracellular signal-regulated kinase) signalling pathway relays extracellular stimuli to elicit changes in cellular function and gene expression. Aberrant activation of this pathway through oncogenic mutations is responsible for a large prop...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature09860
更新日期:2011-04-21 00:00:00