90 research outputs found

    Does Childhood Executive Function Predict Adolescent Functional Outcomes in Girls with ADHD?

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    We prospectively followed an ethnically and socioeconomically diverse sample of preadolescent girls with ADHD (n = 140) and matched comparison girls (n = 88) over a period of 5 years, from middle childhood through early/mid-adolescence. Our aim was to examine the ability of measures of childhood executive function (EF) to predict functional outcomes in adolescence. Measures of neuropsychological functioning comprised the childhood predictors, with academic, social, and global functioning serving as adolescent criterion measures. Results indicated that childhood EF predicted (a) academic achievement and social functioning across our entire sample (independent of diagnostic group status) and (b) global functioning only in girls with ADHD (independent of IQ). These results highlight the non-specificity of EF deficits and suggest the importance of assessing and developing interventions that target EF impairments, particularly in those at high-risk for negative outcomes, in order to prevent long-term difficulties across a range of important functional domains

    Electronic States of Collosal Magnetoresistive Manganites La0.67Pb0.33Mn1xFexO3La_{0.67}Pb_{0.33}Mn_{1-x}Fe_{x}O_{3} from Photoemission Spectroscopy

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    The electron photoemission spectra of valence bands and core-level states of manganese perovskite La0.67Pb0.33(Mn1xFex)O3La_{0.67}Pb_{0.33}(Mn_{1-x}Fe_{x})O_{3} with x = 0, 0.01, 0.03, 0.06, 0.10 and 0.15 were measured by the X-ray and Ultraviolet Photoemission Spectroscopy (XPS and UPS) below and above the metal-insulator transition. From analysis of the Mn 2p core-level spectra the ratio Mn3+//Mn4+Mn^{3+}//Mn^{4+} was calculated as a function of the iron content. Comparison of the valence band spectrum with band structure calculations and with the high-resolution spectra measured at synchrotron radiation for Ca-, Ba- and Ce- substituted manganites revealed the strong hybridisation of Mn 3d and of O 2p states between -3 eV and -7 eV, and no estimated oxygen states between 0 eV and -2 eV where the Mn-3d states play a predominant role. The composition dependent insulating energy gaps were measured at room temperature. Reasons for the behaviour were discussed taking into account previous analysis of XPS/UPS spectra of other manganese perovskites

    Numerical model for phase transformations occurring in multi-phase steel

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    Artykuł prezentuje wyniki prac wykonanych w ramach projektu badawczo rozwojowego nr N R07 0008 04 (nr IMŻ PR 0015) pt.: "Opracowanie podstaw przemysłowych technologii kształtowania struktury i właściwości wyrobów z metali i stopów z wykorzystaniem metod symulacji fizycznej i numerycznej", których celem było opracowanie numerycznego modelu przemian fazowych zachodzących w stali konstrukcyjnej wielofazowej. Opracowanie modelu poprzedziły badania dylatometryczne, których wyniki stanowiły podstawę obliczeń numerycznych. Opracowano modele numeryczne dla stali konstrukcyjnej wielofazowej nie poddawanej odkształceniu, a także odkształconej przy różnych temperaturach, tj. gwarantujących pełną rekrystalizację struktury odkształconego austenitu jak i jej powstrzymanie przed rozpoczęciem chłodzenia. Do identyfikacji parametrów modelu numerycznego wykorzystano metodę obliczeń odwrotnych.The paper presents results of research undertaken to develop the numerical model of phase transformations occurring in multi-phase (CP) steel. Dilatometric measurements were carried out prior to numerical model development. Numerical models were developed both for non-deformed and deformed at different temperatures multi-phase steel. Deformation of the steel was carried out above and below recrystallization temperature of austenite prior to cooling. The inverse method was applied for identification of numerical model parameters

    AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates

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    The YBa2Cu3OδYBa_2Cu_3O_δ films were obtained directly on silver substrates by the sedimentation processes. The thicknesses of these films are of the order of several tens μ. The temperature dependences of the AC susceptibility of the films were measured and analyzed. The critical temperatures of these specimens obtained from the dispersion part of AC susceptibility vary from 89.2 K to 92.5 K. The critical currents were calculated from the absorption part of AC susceptibility using the Bean model. The temperature dependences of the critical currents were fitted using the Ginzburg-Landau strong coupling limit approach

    Resistance and AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates

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    The YBa2Cu3OδYBa_{2}Cu_{3}O_{δ} films were obtained directly on the polished silver substrates by the sedimentation process. Thickness of these films is of the order of several tens micrometers. The temperature dependences of the resistance and the AC susceptibility of the films were measured and analyzed. The critical temperatures of these specimens vary from 89 K to 91 K and they do not depend on the annealing temperatures. The critical currents were calculated from AC susceptibility measurements using the Bean's model

    Resistance and AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates

    No full text
    The YBa2Cu3OδYBa_{2}Cu_{3}O_{δ} films were obtained directly on the polished silver substrates by the sedimentation process. Thickness of these films is of the order of several tens micrometers. The temperature dependences of the resistance and the AC susceptibility of the films were measured and analyzed. The critical temperatures of these specimens vary from 89 K to 91 K and they do not depend on the annealing temperatures. The critical currents were calculated from AC susceptibility measurements using the Bean's model

    Penetration Depth of Magnetic Field into YBa 2

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    The magnetic field penetration depth into YBa₂Cu₃Oₓ film on polycrystalline Ag substrate with the critical temperature of 90.4 K was determined from the AC susceptibility measurements. The 95 μm thick YBCO film was deposited directly on Ag substrate by the sedimentation process. When the sample is in the Meissner state, the dispersive component of the AC susceptibility as well as its temperature dependence reflects the changes of the penetration depth with the temperature. The penetration depth of this film is found to be 5.4 μm

    Critical Currents of Bismuth 1G Tape

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    The critical currents of commercial bismuth based superconducting tape were determined in the two ways. In the first one the transport critical current density was measured by the four points method using the dc current power supply at the liquid nitrogen temperature. In the second one the critical current densities were obtained from the absorption part of ac susceptibility measurements using the Bean model near the critical temperature. The temperature dependence of the critical current densities was fitted to take advantage of the Ginzburg-Landau strong-coupling limit approach. Using the fit parameters the critical current density at 77 K was calculated. The critical temperature of this tape (TcT_{c}= 110.5 K) was determined from the ac susceptibility measurements

    Electronic Band Structure and Photoemission States of La2//3Pb1//3MnO3La_{2//3}Pb_{1//3}MnO_3

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    We present the theoretical study of electronic and magnetic properties in a manganese perovskite La2//3Pb1//3MnO3La_{2//3}Pb_{1//3}MnO_3. The calculations were carried out in frame of the first-principles density functional theory with the general gradient approximation using the WIEN 2K package. The P3c1 crystal structure was taken from the detailed X-ray diffraction data for the perovskite. The exact exchange energy was utilized for Mn d electrons. Density of states was determined by the modified tetrahedron method. As a result we get a valence band for the spin up and down density of states with the gap for the latter of 1.85 eV. We noticed that conduction band is mainly dominated by d spin up manganese electrons and Mn(dxz,dyz)Mn (d_{xz}, d_{yz}) states have twice larger contribution than (dx2y2,dxy)(d_{x^2 - y^2}, d_{xy}). We attribute this to MnO6Mn-O_6 octahedral tilting. From the same reason d3z2r2d_{3z^2 - r^2} state has no contribution to the density of states at the Fermi energy (EF)(E_{F}). Comparison of total density of states with the ultraviolet photoemission spectroscopy measurements shows similar features especially as far as the lead spectral intensity from the 6s electrons at about - 10 eV is concerned. The calculated total magnetic moment per formula unit is 3.66 μBμ_{B}, the measured one 3.48 μBμ_{B}/f.u
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