The Effects of Family, School, and Classroom Ecologies on Changes in Children's Social Competence and Emotional and Behavioral Problems in First Grade.

This study tested the independent and interactive influences of classroom (concentrations of peer prosocial behaviors and victimization), family (household moves, mothers' education), and school (proportion of students receiving income assistance) ecologies on changes in children's social competence (e.g., interpersonal skills, leadership abilities), emotional problems (e.g., anxious, withdrawn behaviors), and behavioral problems (e.g., disruptiveness, aggressiveness) in first grade. Higher classroom concentrations of prosocial behaviors and victimization predicted increases in social competence, and greater school disadvantage predicted decreases. Multiple household moves and greater school disadvantage predicted increases in behavioral problems. Multiple household moves and low levels of mothers' education predicted increases in emotional problems for children in classrooms with few prosocial behaviors. Greater school disadvantage predicted increases in emotional problems for children in classrooms with low prosocial behaviors and high victimization. Policy implications of these findings are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal Conductivity and Phonon Scattering Processes of ALD Grown PbTe–PbSe Thermoelectric Thin Films

This work studies the thermal conductivity and phonon scattering processes in a series of n‐type lead telluride‐lead selenide (PbTe–PbSe) nanostructured thin films grown by atomic layer deposition (ALD). The ALD growth of the PbTe–PbSe samples in this work results in nonepitaxial films grown directly on native oxide/Si substrates, where the Volmer–Weber mode of growth promotes grains with a preferred columnar orientation. The ALD growth of these lead‐rich PbTe, PbSe, and PbTe–PbSe thin films results in secondary oxide phases, along with an increase microstructural quality with increased film thickness. The compositional variation and resulting point and planar defects in the PbTe–PbSe nanostructures give rise to additional phonon scattering events that reduce the thermal conductivity below that of the corresponding ALD‐grown control PbTe and PbSe films. Temperature‐dependent thermal conductivity measurements show that the phonon scattering in these ALD‐grown PbTe–PbSe nanostructured materials, along with ALD‐grown PbTe and PbSe thin films, are driven by extrinsic defect scattering processes as opposed to phonon–phonon scattering processes intrinsic to the PbTe or PbSe phonon spectra. The implication of this work is that polycrystalline, nanostructured ALD composites of thermoelectric PbTe–PbSe films are effective in reducing the phonon thermal conductivity, and represent a pathway for further improvement of the figure of merit (ZT), enhancing their thermoelectric application potential.     

Role of back-diffusion studied by computer simulation

The solidification of Fe-Cr-C alloys was simulated with a program that allowed realistic treatment of diffusion in the liquid and the primary solid phase. It interacts with a thermodynamic databank and can evaluate the heat extraction continuously. Solidification under a constant rate of heat extraction can be simulated. In agreement with previous experience, diffusion of carbon in the fcc phase was found to be very effective, and it can be approximated by an infinitely fast diffusion. The same holds for carbon and chromium in the liquid. The back-diffusion of chromium in the fcc phase was examined in detail. Three different geometries were tested: the planar and cylindrical cases, as well as a new model based on two coupled cylinders. The simulation program allowed the effect of back-diffusion after the end of solidification to be included, and it was found to be important for the segregation ratio.     

Interfacial reactions between B2O3 and spark plasma sintered Yb2Si2O7

Reactions between boria (B₂O₃) and Yb₂Si₂O₇ were studied via a series of idealized interfacial “well” tests. Boria oxidizes out of SiC/SiC ceramic matrix composites (CMCs) where BN is used as a fiber/matrix interphase and boron-rich inclusions often serve as aids in the melt infiltration process. Borate phases are highly reactive and can react with the rare earth silicates currently being utilized as environmental barrier coatings (EBCs) for these CMC systems. Ytterbium disilicate substrates for these well tests are prepared via spark plasma sintering. The well is then drilled into the substrates and filled with a boria glass plug. Exposures in a stagnant-air box furnace show that the boria is reacting with the disilicate via a substitution reaction leaving YbBO₃ and amorphous silica glass as the product phases. This phase was characterized with scanning electron microscopy and elemental dispersive spectroscopy (SEM/EDS), micro-focus X-ray diffraction, and selected-area electron diffraction (SAED). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was also used to analyze water-soluble glassy phases left on the surface of the substrates post-exposure, indicating that the boron content of the glass was decreasing with both increasing exposure times and temperatures. There are few data on the borate product phase properties, however the results of this study suggest that the boria formed via oxidation from the SiC/BN/SiC composites could be detrimental to the performance of Yb₂Si₂O₇ environmental barrier coatings via formation of the borate phase and silica.     

Radio propagation beyond the horizon observed at 1 and 3 GHz compared with predicted reflections from random rough layers

Measurements from the scaled tropospheric scatter links at 1 and 3 GHz Stockholm-Mora have given unexpected results. As a rule, the variation in received signal level in decibels of the half-hour median is three times higher at the lower frequency than at the higher frequency for comparatively low signal levels, whereas for high signal levels it is almost only the signal level at the higher frequency that shows variations. The measurements are compared with the theory of reflections from random rough layers with a linear refractive index stepDelta nand a lengthL, which is shorter than the Fresnel zone and shorter than the glistening surface. The theory is in very good agreement with the measurements.     

Photoelectrochemistry of Self‐Limiting Electrodeposition of Ni Film onto GaAs

Gallium arsenide (GaAs) provides a suitable bandgap (1.43 eV) for solar spectrum absorption and allows a larger photovoltage compared to silicon, suggesting great potential as a photoanode toward water splitting. Photocorrosion under water oxidation condition, however, leads to decomposition or the formation of an insulating oxide layer, which limits the photoelectrochemical performance and stability of GaAs. In this work, a self‐limiting electrodeposition method of Ni on GaAs is reported to either generate ultra‐thin continuous film or nanoislands with high particle density by controlling deposition time. The self‐limiting growth mechanism is validated by potential transients, X‐ray photoelectron spectroscopy composition and depth profile measurements. This deposition method exhibits a rapid nucleation, forms an initial metallic layer followed by a hydroxide/oxyhydroxide nanofilm on the GaAs surface and is independent of layer thickness versus deposition time when coalescence is reached. A photocurrent up to 8.9 mA cm^?2 with a photovoltage of 0.11 V is obtained for continuous ultrathin films, while a photocurrent density of 9.2 mA cm^?2 with a photovoltage of 0.50 V is reached for the discontinuous nanoislands layers in an aqueous solution containing the reversible redox couple K₃Fe(CN)₆/K₄Fe(CN)₆.     

A school-randomized clinical trial of an integrated social–emotional learning and literacy intervention: Impacts after 1 school year.

Objective: To report experimental impacts of a universal, integrated school-based intervention in social–emotional learning and literacy development on change over 1 school year in 3rd-grade children's social–emotional, behavioral, and academic outcomes. Method: This study employed a school-randomized, experimental design and included 942 3rd-grade children (49% boys; 45.6% Hispanic/Latino, 41.1% Black/African American, 4.7% non-Hispanic White, and 8.6% other racial/ethnic groups, including Asian, Pacific Islander, Native American) in 18 New York City public elementary schools. Data on children's social–cognitive processes (e.g., hostile attribution biases), behavioral symptomatology (e.g., conduct problems), and literacy skills and academic achievement (e.g., reading achievement) were collected in the fall and spring of 1 school year. Results: There were main effects of the 4Rs Program after 1 year on only 2 of the 13 outcomes examined. These include children's self-reports of hostile attributional biases (Cohen's d = 0.20) and depression (d = 0.24). As expected based on program and developmental theory, there were impacts of the intervention for those children identified by teachers at baseline with the highest levels of aggression (d = 0.32–0.59) on 4 other outcomes: children's self-reports of aggressive fantasies, teacher reports of academic skills, reading achievement scaled scores, and children's attendance. Conclusions: This report of effects of the 4Rs intervention on individual children across domains of functioning after 1 school year represents an important first step in establishing a better understanding of what is achievable by a schoolwide intervention such as the 4Rs in its earliest stages of unfolding. The first-year impacts, combined with our knowledge of sustained and expanded effects after a second year, provide evidence that this intervention may be initiating positive developmental cascades both in the general population of students and among those at highest behavioral risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)