3,008 research outputs found

    Inhibitory control as a mediator of bidirectional effects between early oppositional behavior and maternal depression.

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    Maternal depression is an established risk factor for child conduct problems, but relatively few studies have tested whether children's behavioral problems exacerbate mothers' depression or whether other child behavioral characteristics (e.g., self-regulation) may mediate bidirectional effects between maternal depression and child disruptive behavior. This longitudinal study examined the parallel growth of maternal depressive symptoms and child oppositional behavior from ages 2 to 5; the magnitude and timing of their bidirectional effects; and whether child inhibitory control, a temperament-based self-regulatory mechanism, mediated effects between maternal depression and child oppositionality. A randomized control trial of 731 at-risk families assessed children annually from ages 2 to 5. Transactional models demonstrated positive and bidirectional associations between mothers' depressive symptoms and children's oppositional behavior from ages 2 to 3, with a less consistent pattern of reciprocal relations up to age 5. Mediation of indirect mother-child effects and child evocative effects depended on the rater of children's inhibitory control. Findings are discussed in regard to how child evocative effects and self-regulatory mechanisms may clarify the transmission of psychopathology within families

    The Matter and the Pseudoscalar Densities in Lattice QCD

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    The matter and the pseudoscalar densities inside a hadron are calculated via gauge-invariant equal-time correlation functions. A comparison is made between the charge charge and the matter density distributions for the pion, the rho, the nucleon and the Δ+\Delta^+ within the quenched theory, and with two flavours of dynamical quarks.Comment: Typos corrected; 13 pages, 16 figure

    Formation, Manipulation, and Elasticity Measurement of a Nanometric Column of Water Molecules

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    Nanometer-sized columns of condensed water molecules are created by an atomic-resolution force microscope operated in ambient conditions. Unusual stepwise decrease of the force gradient associated with the thin water bridge in the tip-substrate gap is observed during its stretch, exhibiting regularity in step heights (~0.5 N/m) and plateau lengths (~1 nm). Such "quantized" elasticity is indicative of the atomic-scale stick-slip at the tip-water interface. A thermodynamic-instability-induced rupture of the water meniscus (5-nm long and 2.6-nm wide) is also found. This work opens a high-resolution study of the structure and the interface dynamics of a nanometric aqueous column.Comment: 4 pages, 3 figure

    Fatigue crack growth and low cycle fatigue of two nickel base superalloys

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    The fatigue crack growth and low cycle fatigue behavior of two P/M superalloys, Rene 95 and Astroloy, in the hot isostatically pressed (HIP) condition, was determined. Test variables included frequency, temperature, environment, and hold times at peak tensile loads (or strains). Crack initiation sites were identified in both alloys. Crack growth rates were shown to increase in argon with decreasing frequency or with the imposition of hold times. This behavior was attributed to the effect of oxygen in the argon. Auger analyses were performed on oxide films formed in argon. Low cycle fatigue lives also were degraded by tensile hold, contrary to previous reports in the literature. The role of environment in low cycle fatigue behavior is discussed

    Signaling microdomains regulate inositol 1,4,5-trisphosphate-mediated intracellular calcium transients in cultured neurons

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    Author Posting. © Society for Neuroscience, 2005. This article is posted here by permission of Society for Neuroscience for personal use, not for redistribution. The definitive version was published in Journal of Neuroscience 25 (2005): 2853-2864, doi:10.1523/JNEUROSCI.4313-04.2005.Ca2+ signals in neurons use specific temporal and spatial patterns to encode unambiguous information about crucial cellular functions. To understand the molecular basis for initiation and propagation of inositol 1,4,5-trisphosphate (InsP3)-mediated intracellular Ca2+ signals, we correlated the subcellular distribution of components of the InsP3 pathway with measurements of agonist-induced intracellular Ca2+ transients in cultured rat hippocampal neurons and pheochromocytoma cells. We found specialized domains with high levels of phosphatidylinositol-4-phosphate kinase (PIPKIγ) and chromogranin B (CGB), proteins acting synergistically to increase InsP3 receptor (InsP3R) activity and sensitivity. In contrast, Ca2+ pumps in the plasma membrane (PMCA) and sarco-endoplasmic reticulum as well as buffers that antagonize the rise in intracellular Ca2+ were distributed uniformly. By pharmacologically blocking phosphatidylinositol-4-kinase and PIPKIγ or disrupting the CGB-InsP3R interaction by transfecting an interfering polypeptide fragment, we produced major changes in the initiation site and kinetics of the Ca2+ signal. This study shows that a limited number of proteins can reassemble to form unique, spatially restricted signaling domains to generate distinctive signals in different regions of the same neuron. The finding that the subcellular location of initiation sites and protein microdomains was cell type specific will help to establish differences in spatiotemporal Ca2+ signaling in different types of neurons.This work was supported by grants from the National Institutes of Health (GM63496, DK61747 to B.E.E., and MH67830 to M.F.Y.), Whitehall Foundation (M.F.Y.), German National Merit Foundation (S.N.J. and C.-U.C.), and Vetenskapsrådet, the Swedish Research Council (P.U.)

    Multiple scalar particle decay and perturbation generation

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    We study the evolution of the universe which contains a multiple number of non-relativistic scalar fields decaying into both radiation and pressureless matter. We present a powerful analytic formalism to calculate the matter and radiation curvature perturbations, and find that our analytic estimates agree with full numerical results within an error of less than one percent. Also we discuss the isocurvature perturbation between matter and radiation components, which may be detected by near future cosmological observations, and point out that it crucially depends on the branching ratio of the decay rate of the scalar fields and that it is hard to make any model independent predictions.Comment: (v1) 22 pages, 4 figures, 2 tables; (v2) JHEP3 style, 24 pages, references added and typos corrected, to appear in JCA
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