Erratum: Genome-scale activation screen identifies a lncRNA locus regulating a gene neighbourhood (original) (raw)
Related papers
Nature Nanotechnology, 2013
Epitaxial growth of SrTiO 3 on silicon by molecular beam epitaxy has opened up the route to the integration of functional complex oxides on a silicon platform. Chief among them is ferroelectric functionality using perovskite oxides such as BaTiO 3. However, it has remained a challenge to achieve ferroelectricity in epitaxial BaTiO 3 films with a polarization pointing perpendicular to the silicon substrate without a conducting bottom electrode. Here, we demonstrate ferroelectricity in such stacks. Synchrotron X-ray diffraction and high-resolution scanning transmission electron microscopy reveal the presence of crystalline domains with the long axis of the tetragonal structure oriented perpendicular to the substrate. Using piezoforce microscopy, polar domains can be written and read and are reversibly switched with a phase change of 1808 8 8 8 8. Open, saturated hysteresis loops are recorded. Thus, ferroelectric switching of 8-to 40-nm-thick BaTiO 3 films in metal-ferroelectric-semiconductor structures is realized, and field-effect devices using this epitaxial oxide stack can be envisaged.
Corrigendum: A network-based analysis of systemic inflammation in humans
Nature, 2005
... Paul E. Bankey 1 , Timothy R. Billiar 2 , David G. Camp 3 , George Casella 4 , Irshad H. Chaudry 5 , Mashkoor A. Choudhry 5 , Charles ... Johnson 14 , Matthew B. Klein 15 , James A. Lederer 16 , Tanya Logvinenko 7 , Ronald V. Maier 11 , John A. Mannick 16 , Philip H. Mason 6 ...
A weak El Niño/Southern Oscillation with delayed seasonal growth around 4,300 years ago
Nature Geoscience, 2013
Niño/Southern Oscillation (ENSO). Palaeoclimate records indicate a lower ENSO variance during the middle Holocene compared with today 1-6 ; however, model simulations have not reproduced the full magnitude of the changes 7-10 , and whether external forcing drives large intrinsic ENSO variability 11 is therefore a matter of considerable debate. Here we present a 175-year-long, monthly resolved oxygen isotope record, obtained from a Porites coral microatoll located on Kiritimati (Christmas) Island, in the NINO3.4 region of the central equatorial Pacific. Our quantitative record of ENSO variability about 4,300 years ago shows that ENSO variance was persistently reduced by 79%, compared with today, and it exhibits a dominant annual cycle. Season-specific analysis shows that El Niño events were damped during their September-November growth phase, and delayed relative to the climatological year. We suggest that the higher boreal summer insolation at the time strengthened the tropical Pacific zonal winds as well as the gradients in sea surface temperature, and thereby led to an enhanced annual cycle and suppressed ENSO. As the weak ENSO is subject to interdecadal amplitude modulation, we conclude that amplitude modulation is likely to remain robust under altered climates. Our findings show that ENSO is capable of responding to external forcing.
At suuciently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP) 1. Such an exotic state of strongly interacting quantum chro-modynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed 2–6. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions 7 , is more pronounced for multi-strange baryons. Several eeects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions 8,9 , but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton–proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p–Pb collision results 10,11 , indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb–Pb collisions, where a QGP is formed. The production of strange hadrons in high-energy hadronic interactions provides a way to investigate the properties of quantum chromodynamics (QCD), the theory of strongly interacting matter. Unlike up (u) and down (d) quarks, which form ordinary matter, strange (s) quarks are not present as valence quarks in the initial state, yet they are sufficiently light to be abundantly created during the course of the collisions. In the early stages of high-energy collisions, strangeness is produced in hard (perturbative) 2 → 2 partonic scattering processes by flavour creation (gg → s¯ s, q¯ q → s¯ s) and flavour excitation (gs → gs, qs → qs). Strangeness is also created during the subsequent partonic evolution via gluon splittings (g → s¯ s). These processes tend to dominate the production of high transverse momentum (p T) strange hadrons. At low p T , non-perturbative processes dominate the production of strange hadrons. In string fragmentation models the production of strange hadrons is generally suppressed relative to hadrons containing only light quarks, as the strange quark is heavier than up and down quarks. The amount of strangeness suppression in elementary (e + e − and pp) collisions is an important parameter in Monte Carlo (MC) models. For this reason, measurements of strange hadron production place constraints on these models. The abundances of strange particles relative to pions in heavy-ion collisions from top RHIC (Relativistic Heavy-Ion Collider) to LHC (Large Hadron Collider) energies do not show a significant dependence on either the initial volume (collision centrality) or the initial energy density (collision energy). With the exception of the most peripheral collisions, particle ratios are found to be compatible with those of a hadron gas in thermal and chemical equilibrium and can be described using a grand-canonical statistical model 12,13. In peripheral collisions, where the overlap of the colliding nuclei becomes very small, the relative yields of strange particles to pions decrease and tend toward those observed in pp collisions, for which a statistical-mechanics approach can also be applied 14,15. Extensions of a pure grand-canonical description of particle production , such as statistical models implementing strangeness canon-ical suppression 16 and core–corona superposition 17,18 models, can effectively produce a suppression of strangeness production in small systems. However, the microscopic origin of enhanced strangeness production is not known, and the measurements presented in this Letter may contribute to its understanding. Several effects, such as azimuthal correlations and mass-dependent hardening of p T distributions , which in nuclear collisions are typically attributed to the formation of a strongly interacting quark–gluon medium, have been observed in high-multiplicity pp and proton–nucleus collisions at the LHC 8–11,19–25. Yet, enhanced production of strange particles as a function of the charged-particle multiplicity density (dN ch /dη) has so far not been observed in pp collisions. The study of pp collisions at high multiplicity is thus of considerable interest as it opens the exciting possibility of a microscopic understanding of phenomena known from nuclear reactions. In this Letter, we present the multiplicity dependence of the production of primary strange (K 0 S , Λ, Λ) and multi-strange (Ξ − , Ξ + , Ω − , Ω +) hadrons in pp collisions at the centre-of-mass energy of √ s = 7 TeV. Primary particles are defined as all particles created in the collisions, except those coming from weak decays of light-flavour hadrons and of muons. The measurements have been performed at midrapidity (the particle rapidity is defined as y = (1/2) ln((E + p z c)/(E − p z c)), where E is the energy and p z is the component of momentum along the beam axis), y < 0.5, with the ALICE detector 26 at the LHC. Similar measurements of the multiplicity and centrality dependence of strange and multi-strange hadron production have been performed by ALICE in proton– lead (p–Pb) collisions at a centre-of-mass energy per nucleon pair √ s NN = 5.02 TeV (refs 10,11) and in lead–lead (Pb–Pb) collisions at √ s NN = 2.76 TeV (refs 6,27). The measurements reported here have been obtained in pp collisions at √ s = 7 TeV for events having at least one charged particle produced in the pseudorapidity (the particle pseudorapidity is defined as η = − ln(tan(θ/2)), where θ is the angle with respect to the beam axis) interval |η| < 1 (INEL > 0), corresponding to about 75% of the total inelastic cross-section. To study the multiplicity dependence of strange and multi-strange hadron production, the sample is divided into event classes based on the total ionization energy deposited in the forward detectors, covering the pseudorapidity regions 2.8 < η < 5.1 and −3.7 < η < −1.7. Particle/antiparticle production yields are identical within uncertainties. The p T distributions of K 0 S , Λ + Λ, Ξ − + Ξ + and Ω − + Ω + (in the following denoted as K 0 S , Λ, Ξ and Ω) are shown in Fig. 1 for a selection of event classes with progressively decreasing † A full list of authors and aaliations appears at the end of the paper. NATURE PHYSICS | ADVANCE ONLINE PUBLICATION | www.nature.com/naturephysics
Astronomical pacing of methane release in the Early Jurassic period
Nature, 2005
A pronounced negative carbon-isotope (d 13 C) excursion of ,5-7‰ (refs 1-7) indicates the occurrence of a significant perturbation to the global carbon cycle during the Early Jurassic period (early Toarcian age, ,183 million years ago). The rapid release of 12 C-enriched biogenic methane as a result of continental-shelf methane hydrate dissociation has been put forward as a possible explanation for this observation 1, . Here we report high-resolution organic carbon-isotope data from well-preserved mudrocks in Yorkshire, UK, which demonstrate that the carbon-isotope excursion occurred in three abrupt stages, each showing a shift of 22‰ to 23‰. Spectral analysis of these carbon-isotope measurements and of high-resolution carbonate abundance data reveals a regular cyclicity. We interpret these results as providing strong evidence that methane release proceeded in three rapid pulses and that these pulses were controlled by astronomically forced changes in climate, superimposed upon longer-term global warming. We also find that the first two pulses of methane release each coincided with the extinction of a large proportion of marine species .
Interoception and the Neurovisceral Axis as a Modal Basis for Computational Neuroecology
The defining parameters of neuroecology stand to benefit from a phenomenological expansion that includes the role of affect qua interoception as entailing a multimodal storehouse for specialized signal processing and brain architecture within the neurovisceral axis. The relationship between the gut and the brain represents an integral axis of communication drawing from the ecosystem of the microbiome as an environment for nerve-cell processes reflecting our habits of living and the influence of the luminal environment in higher-ordered cognition. This is shown to apply in both feedforward and inferential models of interoception. A surplus of evidence in recent years indicates that interoception and interoceptive awareness play a key role in influencing adaptive behavioral strategies, cognition, homeostatic regulation, decision-making, social relations and action. The groundwork for this expansion has already been positioned by preliminary efforts to offer a physiological basis for computational neuroecology and emotion qua somatic markers. Building off of their maiden report, this paper develops the richer neuroscientific landscape underwriting somatic markers in the context of the neurovisceral axis qua interoception and biological intuition. In the process we encounter an evolutionarily-rare and morphologically-specialized type of neuron conjectured to provide an advantage for social processing that eclipses the rudimentary notion of somatic markers, alone, and thereby enriches the descriptive landscape of neuroecological phenomena. Finally, we examine the inherent signal processing dynamics in cortical laminar layers as rendered in a newly-fashioned predictive coding account of interoception as a " limbic workspace theory " that interfaces with sensory signals between agranular and granular cells. Advances in predictive coding models and the free-energy principle stand poised to provide a unified model of neural signal processing encompassing sensory coding as well as adaptation in neurons, mood and behavior.The incorporation of interoceptive inference sheds critical light on anticipatory (feedback) signal-processing mechanisms in the brain. This suggests that an incorporation of interoceptive affect-in combination with cognition and adaptation-will shed critical light on further efforts to organize the driving epistemic structure and phenomenology associated with neuroecology.
American Journal of Physiology-Gastrointestinal and Liver Physiology
Congenital Tufting Enteropathy (CTE) is an autosomal recessive disease characterized by severe intestinal failure in infancy and mutations in the epithelial cell adhesion molecule ( EPCAM) gene. Previous studies of CTE in mice expressing mutant EpCAM show neonatal lethality. Hence, to study the cellular, molecular, and physiological alterations that result from EpCAM mutation, a tamoxifen-inducible mutant EpCAM enteroid model has been generated. The presence of mutant EpCAM in the model was confirmed at both mRNA and protein levels. Immunofluorescence microscopy demonstrated the reduced expression of mutant EpCAM. Mutant enteroids had reduced budding potential as well as significantly decreased mRNA expression for epithelial lineage markers ( Mucin 2, Lysozyme, Sucrase-Isomaltase ), proliferation marker Ki67 and secretory pathway transcription factors ( Atoh1, Hnf1b). Significantly decreased numbers of Paneth and goblet cells were confirmed by staining. These findings were correlate...