3,528 research outputs found

    Twisted atrioventricular connections in double inlet right ventricle: evaluation by magnetic resonance imaging

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    Twisted atrioventricular connections occur almost exclusively in the hearts with biventricular atrioventricular connections. Only one example of double inlet left ventricle has been illustrated in which the axes of the two atrioventricular valves crossed each other. We describe herein three patients, and one autopsied specimen, with double inlet right ventricle in which magnetic resonance imaging clearly demonstrated twisted atrioventricular connections

    Reduction in CO2 uptake rates of red tide dinoflagellates due to mixotrophy

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    We investigated a possible reduction in CO2 uptake rate by phototrophic red tide dinoflagellates arising from mixotrophy. We measured the daily ingestion rates of Prorocentrum minimum by Prorocentrum micans over 5 days in 10 L experimentalbottles, and the uptake rates of total dissolved inorganic carbon (CT) by a mixture of P. micans and P. minimum(mixotrophic growth), and for the predator P. micans (phototrophic growth; control) and prey P. minimum (phototrophicgrowth; control) alone. To account for the effect of pH on the phototrophic growth rates of P. micans and P. minimum,measurements of CT and pH in the predator and prey control bottles were continued until the pH reached the same level(pH 9.5) as that in the experimental bottles on the final day of incubation. The measured total CT uptake rate by the mixtureof P. micans and P. minimum changed from 123 to 161 μmol CT kg-1 d-1 over the course of the experiment, and waslower than the CT uptake rates shown by P. micans and P. minimum in the predator and prey control bottles, respectively,which changed from 132 to 176 μmol CT kg-1 d-1 over the course of the experiment. The reduction in total CT uptake ratearising from the mixotrophy of P. micans was 7-31% of the daily CT uptake rate seen during photosynthesis. The resultssuggest that red tide dinoflagellates take up less CT during mixotrophy.1131Ysciescopuskc

    Unquenched QCD with Light Quarks

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    We present recent results in unquenched lattice QCD with two degenerate light sea quarks using the truncated determinant approximation (TDA). In the TDA the infrared modes contributing to the quark determinant are computed exactly up to some cutoff in quark off-shellness (typically 2ΛQCD\Lambda_{QCD}). This approach allows simulations to be performed at much lighter quark masses than possible with conventional hybrid MonteCarlo techniques. Results for the static energy and topological charge distributions are presented using a large ensemble generated on very coarse (64^4) but physically large lattices. Preliminary results are also reported for the static energy and meson spectrum on 103^3x20 lattices (lattice scale a1a^{-1}=1.15 GeV) at quark masses corresponding to pions of mass \leq 200 MeV. Using multiboson simulation to compute the ultraviolet part of the quark determinant the TDA approach becomes an exact with essentially no increase in computational effort. Some preliminary results using this fully unquenched algorithm are presented.Comment: LateX, 39 pages, 16 eps figures, 1 ps figur

    Dynamical mean-field approach to materials with strong electronic correlations

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    We review recent results on the properties of materials with correlated electrons obtained within the LDA+DMFT approach, a combination of a conventional band structure approach based on the local density approximation (LDA) and the dynamical mean-field theory (DMFT). The application to four outstanding problems in this field is discussed: (i) we compute the full valence band structure of the charge-transfer insulator NiO by explicitly including the p-d hybridization, (ii) we explain the origin for the simultaneously occuring metal-insulator transition and collapse of the magnetic moment in MnO and Fe2O3, (iii) we describe a novel GGA+DMFT scheme in terms of plane-wave pseudopotentials which allows us to compute the orbital order and cooperative Jahn-Teller distortion in KCuF3 and LaMnO3, and (iv) we provide a general explanation for the appearance of kinks in the effective dispersion of correlated electrons in systems with a pronounced three-peak spectral function without having to resort to the coupling of electrons to bosonic excitations. These results provide a considerable progress in the fully microscopic investigations of correlated electron materials.Comment: 24 pages, 14 figures, final version, submitted to Eur. Phys. J. for publication in the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and Ordering of Microscopic Degrees of Freedom

    Selective formation of tungsten nanowires

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    We report on a process for fabricating self-aligned tungsten (W) nanowires with polycrystalline silicon core. Tungsten nanowires as thin as 10 nm were formed by utilizing polysilicon sidewall transfer technology followed by selective deposition of tungsten by chemical vapor deposition (CVD) using WF6 as the precursor. With selective CVD, the process is self-limiting whereby the tungsten formation is confined to the polysilicon regions; hence, the nanowires are formed without the need for lithography or for additional processing. The fabricated tungsten nanowires were observed to be perfectly aligned, showing 100% selectivity to polysilicon and can be made to be electrically isolated from one another. The electrical conductivity of the nanowires was characterized to determine the effect of its physical dimensions. The conductivity for the tungsten nanowires were found to be 40% higher when compared to doped polysilicon nanowires of similar dimensions

    Poplar GTL1 Is a Ca2+/Calmodulin-Binding Transcription Factor that Functions in Plant Water Use Efficiency and Drought Tolerance

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    Diminishing global fresh water availability has focused research to elucidate mechanisms of water use in poplar, an economically important species. A GT-2 family trihelix transcription factor that is a determinant of water use efficiency (WUE), PtaGTL1 (GT-2 like 1), was identified in Populus tremula × P. alba (clone 717-IB4). Like other GT-2 family members, PtaGTL1 contains both N- and C-terminal trihelix DNA binding domains. PtaGTL1 expression, driven by the Arabidopsis thaliana AtGTL1 promoter, suppressed the higher WUE and drought tolerance phenotypes of an Arabidopsis GTL1 loss-of-function mutation (gtl1-4). Genetic suppression of gtl1-4 was associated with increased stomatal density due to repression of Arabidopsis STOMATAL DENSITY AND DISTRIBUTION1 (AtSDD1), a negative regulator of stomatal development. Electrophoretic mobility shift assays (EMSA) indicated that a PtaGTL1 C-terminal DNA trihelix binding fragment (PtaGTL1-C) interacted with an AtSDD1 promoter fragment containing the GT3 box (GGTAAA), and this GT3 box was necessary for binding. PtaGTL1-C also interacted with a PtaSDD1 promoter fragment via the GT2 box (GGTAAT). PtaSDD1 encodes a protein with 60% primary sequence identity with AtSDD1. In vitro molecular interaction assays were used to determine that Ca2+-loaded calmodulin (CaM) binds to PtaGTL1-C, which was predicted to have a CaM-interaction domain in the first helix of the C-terminal trihelix DNA binding domain. These results indicate that, in Arabidopsis and poplar, GTL1 and SDD1 are fundamental components of stomatal lineage. In addition, PtaGTL1 is a Ca2+-CaM binding protein, which infers a mechanism by which environmental stimuli can induce Ca2+ signatures that would modulate stomatal development and regulate plant water use

    The Formation of the First Massive Black Holes

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    Supermassive black holes (SMBHs) are common in local galactic nuclei, and SMBHs as massive as several billion solar masses already exist at redshift z=6. These earliest SMBHs may grow by the combination of radiation-pressure-limited accretion and mergers of stellar-mass seed BHs, left behind by the first generation of metal-free stars, or may be formed by more rapid direct collapse of gas in rare special environments where dense gas can accumulate without first fragmenting into stars. This chapter offers a review of these two competing scenarios, as well as some more exotic alternative ideas. It also briefly discusses how the different models may be distinguished in the future by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First Galaxies - Theoretical Predictions and Observational Clues", Springer Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B. Mobasher, in pres

    Scapinin, the Protein Phosphatase 1 Binding Protein, Enhances Cell Spreading and Motility by Interacting with the Actin Cytoskeleton

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    Copyright (c) 2009 Sagara et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Scapinin, also named phactr3, is an actin and protein phosphatase 1 (PP1) binding protein, which is expressed in the adult brain and some tumor cells. At present, the role(s) of scapinin in the brain and tumors are poorly understood. We show that the RPEL-repeat domain of scapinin, which is responsible for its direct interaction with actin, inhibits actin polymerization in vitro. Next, we established a Hela cell line, where scapinin expression was induced by tetracycline. In these cells, expression of scapinin stimulated cell spreading and motility. Scapinin was colocalized with actin at the edge of spreading cells. To explore the roles of the RPEL-repeat and PP1-binding domains, we expressed wild-type and mutant scapinins as fusion proteins with green fluorescence protein (GFP) in Cos7 cells. Expression of GFP-scapinin (wild type) also stimulated cell spreading, but mutation in the RPEL-repeat domain abolished both the actin binding and the cell spreading activity. PP1-binding deficient mutants strongly induced cell retraction. Long and branched cytoplasmic processes were developed during the cell retraction. These results suggest that scapinin enhances cell spreading and motility through direct interaction with actin and that PP1 plays a regulatory role in scapinin-induced morphological changes.ArticlePLOS ONE. 4(1):e4247 (2009)journal articl

    J/ψ\rm{J}/\psi production at low transverse momentum in p+p and d+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We report on the measurement of J/ψ\rm{J}/\psi production in the dielectron channel at mid-rapidity (|y|<1) in p+p and d+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum pTp_{T} spectra in p+p for pTp_{T} < 4 GeV/c and d+Au collisions for pTp_{T} < 3 GeV/c are presented. These measurements extend the STAR coverage for J/ψ\rm{J}/\psi production in p+p collisions to low pTp_{T}. The from the measured J/ψ\rm{J}/\psi invariant cross section in p+p and d+Au collisions are evaluated and compared to similar measurements at other collision energies. The nuclear modification factor for J/ψ\rm{J}/\psi is extracted as a function of pTp_{T} and collision centrality in d+Au and compared to model calculations using the modified nuclear Parton Distribution Function and a final-state J/ψ\rm{J}/\psi nuclear absorption cross section
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