Abstract:
:Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.
journal_name
Proc Natl Acad Sci U S Aauthors
Mantelli E,Bertagni MB,Ridolfi Ldoi
10.1073/pnas.1600362113subject
Has Abstractpub_date
2016-08-09 00:00:00pages
E4594-600issue
32eissn
0027-8424issn
1091-6490pii
1600362113journal_volume
113pub_type
杂志文章abstract::The p21(WAF1) (p21) cyclin-dependent kinase inhibitor plays a major role in regulating cell cycle arrest. It was recently reported that the p53-independent elevation of p21 protein levels is essential in mediating the G(1) arrest resulting from signal transduction events initiated by the crosslinking of membrane IgM o...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.15.8711
更新日期:1999-07-20 00:00:00
abstract::Terrorist attacks often fuel online hate and increase the expression of xenophobic and antiminority messages. Previous research has focused on the impact of terrorist attacks on prejudiced attitudes toward groups linked to the perpetrators as the cause of this increase. We argue that social norms can contain the expre...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2007977117
更新日期:2020-09-15 00:00:00
abstract::A three-plasmid system for heterologous expression of 6-deoxyerythronolide B synthase (DEBS) has been developed to facilitate combinatorial biosynthesis of polyketides made by type I modular polyketide synthases (PKSs). The eryA PKS genes encoding the three DEBS subunits were individually cloned into three compatible ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.21.11740
更新日期:1999-10-12 00:00:00
abstract::Flagellar microtubules from Chlamydomonas and sea urchin sperm were used as in vitro assembly sites for chick brain tubulin. Brain microtubules assembled onto the A-tubules, central tubules, and, to a limited extent, onto the distal ends of the axonemes at low tubulin concentrations and onto distal and proximal ends a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.72.3.1122
更新日期:1975-03-01 00:00:00
abstract::Normal human cells whether embryonic, neonatal, or adult are resistant to experimentally induced tumorigenesis in contrast to rodent or chicken cells. We showed previously that neither transformation with simian virus 40 DNA nor transfection with human mutant HRAS DNA immortalized FS-2 cells (diploid, neonatal human f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.22.8659
更新日期:1986-11-01 00:00:00
abstract::The presence of nerve growth factor (NGF) mRNA and protein in the rat central nervous system is documented. Blot-hybridization analysis showed an abundance of NGF mRNA in the hippocampus, cerebral cortex, and olfactory bulb. Enzyme immunoassay confirmed significant levels of a NGF-like protein in the hippocampus and c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.3.817
更新日期:1986-02-01 00:00:00
abstract::Despite the importance of aggression in the behavioral repertoire of most animals, relatively little is known of its proximate causation and control. To take advantage of modern methods of genetic analysis for studying this complex behavior, we have developed a quantitative framework for studying aggression in common ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.082102599
更新日期:2002-04-16 00:00:00
abstract::Several of the best-studied sex differences in the mammalian brain are ascribed to the hormonal control of cell death. This conclusion is based primarily on correlations between pyknotic cell counts in development and counts of mature neurons in adulthood; the molecular mechanisms of hormone-regulated, sexually dimorp...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0404644101
更新日期:2004-09-14 00:00:00
abstract::GDP-dissociation inhibitors (GDIs) play a primary role in modulating the activation of GTPases and may also be critical for the cellular compartmentalization of GTPases. RhoGDI and GDI/D4 are two currently known GDIs for the Rho-subfamily of GTPases. Using their cDNAs to screen a human brain cDNA library under low str...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.9.4279
更新日期:1997-04-29 00:00:00
abstract::Incommensurate charge order in hole-doped oxides is intertwined with exotic phenomena such as colossal magnetoresistance, high-temperature superconductivity, and electronic nematicity. Here, we map, at atomic resolution, the nature of incommensurate charge-lattice order in a manganite using scanning transmission elect...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1714901115
更新日期:2018-02-13 00:00:00
abstract::Learning theories hypothesize specific circuits encode essential information for performance. For simple tasks in invertebrates and mammals, the essential circuits are known, but for cognitive functions, the essential circuits remain unidentified. Here, we show that some essential information for performing a choice t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0912950107
更新日期:2010-08-10 00:00:00
abstract::We have grown crystals of a soluble recombinant form of human CD4, a transmembrane glycoprotein found predominantly on the surface of helper T cells. Crystals composed of the entire extracellular portion of CD4 exhibit extensive polymorphism. Of the five crystal types that have been grown, the best diffracts to Bragg ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.16.6423
更新日期:1990-08-01 00:00:00
abstract::Although much of the brain's functional organization is genetically predetermined, it appears that some noninnate functions can come to depend on dedicated and segregated neural tissue. In this paper, we describe a series of experiments that have investigated the neural development and organization of one such noninna...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.95.3.847
更新日期:1998-02-03 00:00:00
abstract::The generalized master equations (GMEs) that contain multiple time scales have been derived quantum mechanically. The GME method has then been applied to a model of charge migration in proteins that invokes the hole hopping between local amino acid sites driven by the torsional motions of the floppy backbones. This mo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.140196597
更新日期:2000-08-29 00:00:00
abstract::The acetylcholine receptor is a protein that contains certain critical disulfide bonds. Experiments were designed to determine the role such bonds might play in the physiological activity of the receptor. Modification of the receptor with sodium bisulfite and diamide produced an increase in the time constants of the m...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.78.12.7806
更新日期:1981-12-01 00:00:00
abstract::GSTs catalyze the conjugation of glutathione with a wide variety of hydrophobic compounds, generally resulting in nontoxic products that can be readily eliminated. In contrast to many other organisms, the malarial parasite Plasmodium falciparum possesses only one GST isoenzyme (PfGST). This GST is highly abundant in t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2333763100
更新日期:2003-11-25 00:00:00
abstract::Human X chromosome DNA was partially purified from a mouse-human hybrid cell line containing a single human chromosome, the X. Enrichment of such DNA was accomplished by two sequential reassociations of radiolabeled hybrid cell DNA with large excesses of mouse DNA. Unreassociated hybrid cell DNA was used as a probe fo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.12.6525
更新日期:1979-12-01 00:00:00
abstract::The light-entrained master central circadian clock (CC) located in the suprachiasmatic nucleus (SCN) not only controls the diurnal alternance of the active phase (the light period of the human light-dark cycle, but the mouse dark period) and the rest phase (the human dark period, but the mouse light period), but also ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1519807112
更新日期:2015-12-01 00:00:00
abstract::Individual cell types are defined by architecturally and functionally specialized cortical domains. The Ezrin, Radixin, and Moesin (ERM) proteins play a major role in organizing cortical domains by assembling membrane protein complexes and linking them to the cortical actin cytoskeleton. Many studies have focused on t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1103418108
更新日期:2011-07-19 00:00:00
abstract::A light beam hitting the retina produces an excitatory process; however, around the edge of the light beam, sensory cells are inhibited and lose their sensitivity. This combination of stimulation and inhibition produces a discrepancy between the luminance pattern presented to the eye and the brightness pattern that is...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.69.4.885
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abstract::Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth-ocean-atmosphere dynamic exchange of elements. The ratios' dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1918943117
更新日期:2020-09-08 00:00:00
abstract::P450c17 is the single enzyme mediating both 17 alpha-hydroxylase (steroid 17 alpha-monooxygenase, EC 1.14.99.9) and 17,20 lyase activities in the synthesis of steroid hormones. It has been suggested that different P450c17 isozymes mediate these activities in the adrenal gland and testis. We sequenced 423 of the 509 am...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.2.407
更新日期:1987-01-01 00:00:00
abstract::Classic physiology studies dating to the 1930s demonstrate that moderate or transient glucocorticoid (GC) exposure improves muscle performance. The ergogenic properties of GCs are further evidenced by their surreptitious use as doping agents by endurance athletes and poorly understood efficacy in Duchenne muscular dys...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1512968112
更新日期:2015-12-08 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1118579109
更新日期:2012-01-03 00:00:00
abstract::Tetrodotoxin was infused into the suprachiasmatic nuclei of unanesthetized and unrestrained rats continuously for 14 days. The internal timekeeping mechanism of the circadian pacemaker in the nuclei continued to oscillate unaffected by this treatment, although the toxin reversibly blocked function of both the input pa...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.6.1694
更新日期:1987-03-01 00:00:00
abstract::Early abstract reasoning has typically been characterized by a "relational shift," in which children initially focus on object features but increasingly come to interpret similarity in terms of structured relations. An alternative possibility is that this shift reflects a learned bias, rather than a typical waypoint a...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2019-07-09 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2019-10-08 00:00:00
abstract::Plasma norepinephrine and dopamine beta-hydroxylase (EC 1.14.17.1) activity were measured in rats. Adrenergic neuron blockade with bretylium for 4 hr and ganglion blockade with chlorisondamine for 72 hr lowered plasma norepinephrine. Neither treatment altered plasma dopamine beta-hydroxylase activity. Phenoxybenzamine...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.11.4392
更新日期:1974-11-01 00:00:00
abstract::The human beta-globin locus is activated transcriptionally by a complex series of events that culminate in appropriate temporal and tissue-specific control over five separate genes during embryonic and early postnatal development. One cis-regulatory element in the locus, originally identified as an enhancer 3' to the ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.17.9944
更新日期:1998-08-18 00:00:00
abstract::A series of small peptides corresponding to the amino termini of the fibrin alpha- and beta-chains has been synthesized. The peptides glycyl-L-prolyl-L-arginyl-L-proline and glycyl-L-prolyl-L-arginylsarcosine are potent inhibitors of fibrin polymerization. Moreover, these peptides have a natural stability stemming fro...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.75.7.3085
更新日期:1978-07-01 00:00:00