A multilevel analysis of racial discipline disproportionality: A focus on student perceptions of academic engagement and disciplinary environment.

Excessive use of exclusionary school discipline with Black students is a persistent, systemic problem in U.S. schools with potential to affect students' perceptions of their school. For example, students may notice racial differences in out-of-school suspensions, which may relate to how academically engaged they feel and the extent to which they view the school's disciplinary environment as positive. The current study investigated school-level racial discipline disproportionality and observed classroom-level, positive behavior supports in relation to student perceptions of academic engagement and school disciplinary environment by fitting a series of three-level models, which included data on students (N = 17,115), classrooms (J = 310), and schools (K = 53). Two metrics of discipline disproportionality were used (i.e., the risk ratio and the risk difference) and moderation was examined through cross-level interactions. Results indicated that, regardless of race, students perceived the disciplinary environment as significantly less favorable in schools with greater racial discipline disproportionality when measured by the risk ratio, but not when measured by the risk difference. Using different disproportionality metrics in education research has important implications for policies and practices to identify and address the issue. How discipline disparities relate to the way that students perceive the disciplinary environment will likely inform intervention efforts for school psychologists.

Reducing Behavior Problems Among Students with Autism Spectrum Disorder: Coaching Teachers in a Mixed-Reality Setting.

Most approaches aiming to reduce behavior problems among youth with Autism Spectrum Disorder (ASD) focus on individual students; however, school personnel also need professional development to better support students. This study targeted teachers' skill development to promote positive outcomes for students with ASD. The sample included 19 teachers in two non-public special education settings serving students with moderate to severe ASD. Participating teachers received professional development and coaching in classroom management, with guided practice in a mixed-reality simulator. Repeated-measures ANOVAs examining externally-conducted classroom observations revealed statistically significant improvements in teacher management and student behavior over time. Findings suggest that coaching and guided practice in a mixed-reality simulator is perceived as acceptable and may reduce behavior problems among students with ASD.

Comparing land surface phenology derived from satellite and GPS network microwave remote sensing.

The land surface phenology (LSP) start of season (SOS) metric signals the seasonal onset of vegetation activity, including canopy growth and associated increases in land-atmosphere water, energy and carbon (CO2) exchanges influencing weather and climate variability. The vegetation optical depth (VOD) parameter determined from satellite passive microwave remote sensing provides for global LSP monitoring that is sensitive to changes in vegetation canopy water content and biomass, and insensitive to atmosphere and solar illumination constraints. Direct field measures of canopy water content and biomass changes desired for LSP validation are generally lacking due to the prohibitive costs of maintaining regional monitoring networks. Alternatively, a normalized microwave reflectance index (NMRI) derived from GPS base station measurements is sensitive to daily vegetation water content changes and may provide for effective microwave LSP validation. We compared multiyear (2007-2011) NMRI and satellite VOD records at over 300 GPS sites in North America, and their derived SOS metrics for a subset of 24 homogenous land cover sites to investigate VOD and NMRI correspondence, and potential NMRI utility for LSP validation. Significant correlations (P<0.05) were found at 276 of 305 sites (90.5 %), with generally favorable correspondence in the resulting SOS metrics (r (2)=0.73, P<0.001, RMSE=36.8 days). This study is the first attempt to compare satellite microwave LSP metrics to a GPS network derived reflectance index and highlights both the utility and limitations of the NMRI data for LSP validation, including spatial scale discrepancies between local NMRI measurements and relatively coarse satellite VOD retrievals.

Absolute calibration of a geodetic time transfer system.

An absolute calibration technique is developed for geodetic Global Positioning System (GPS) receivers. An uncertainty budget for the system (receiver, cables, connectors, antenna) is evaluated, yielding 1.1 ns at each frequency, and 1.6 ns for a two-receiver experiment. Analysis of data on a short baseline yields 0.8 and 1.2 ns agreement on P1 and P2, respectively.

Long-term comparisons between two-way satellite and geodetic time transfer systems.

Global Positioning System (GPS) observations recorded in the United States and Europe were used to evaluate time transfer capabilities of GETT (geodetic time transfer). Timing estimates were compared with two-way satellite time and frequency transfer (TWSTFT) systems. A comparison of calibrated links at the U.S. Naval Observatory, Washington, D.C., and Colorado Springs, CO, yielded agreement of 2.17 ns over 6 months with a standard deviation of 0.73 ns. An uncalibrated link between the National Institute of Standards and Technology (NIST) and Physikalisch-Technische Bundesanstalt, Braunschweig, Germany, has a standard deviation of 0.79 ns over the same time period.

Using 1-Hz GPS data to measure deformations caused by the Denali fault earthquake.

The 3 November 2002 moment magnitude 7.9 Denali fault earthquake generated large, permanent surface displacements in Alaska and large-amplitude surface waves throughout western North America. We find good agreement between strong ground-motion records integrated to displacement and 1-hertz Global Positioning System (GPS) position estimates collected approximately 140 kilometers from the earthquake epicenter. One-hertz GPS receivers also detected seismic surface waves 750 to 3800 kilometers from the epicenter, whereas these waves saturated many of the seismic instruments in the same region. High-frequency GPS increases the dynamic range and frequency bandwidth of ground-motion observations, providing another tool for studying earthquake processes.

Surface melt-induced acceleration of Greenland ice-sheet flow.

Ice flow at a location in the equilibrium zone of the west-central Greenland Ice Sheet accelerates above the midwinter average rate during periods of summer melting. The near coincidence of the ice acceleration with the duration of surface melting, followed by deceleration after the melting ceases, indicates that glacial sliding is enhanced by rapid migration of surface meltwater to the ice-bedrock interface. Interannual variations in the ice acceleration are correlated with variations in the intensity of the surface melting, with larger increases accompanying higher amounts of summer melting. The indicated coupling between surface melting and ice-sheet flow provides a mechanism for rapid, large-scale, dynamic responses of ice sheets to climate warming.