374 research outputs found
Variation found in rates of restraint and seclusion among students with a disability
The restraint and seclusion of individuals—practices usually associated with highly restrictive environments—are extreme responses to student behavior used in some public schools. In this brief, authors Douglas Gagnon, Marybeth Mattingly, and Vincent Connelly report that restraint and seclusion are used much more frequently on students with a disability than on students without a disability. In addition, the majority of U.S. school districts does not restrain or seclude students with a disability; 59.3 percent of districts report no instances of restraint, while 82.5 percent do not report a single instance of seclusion. However, a small proportion of districts report exceedingly high rates. The authors also find that low-poverty, low-diversity school districts use restraint and seclusion on students with a disability more than twice as often as high-poverty, high-diversity districts. The authors conclude that, overall, the relationships between restraint and seclusion rates, and disability type and school characteristics, warrant further research. This brief draws on data from the 2009–2010 Civil Rights Data Collection and the 2009 Small Area Income and Poverty Estimates
Restraint and Seclusion of Students With a Disability Continue to Be Common in Some School Districts Patterns Remain Relatively Consistent Despite Recent Policy Changes
In 2013, Carsey released a brief that analyzed rates of restraint and seclusion using a large, nationally representative data set of U.S. school districts. This brief, which analyzes a more comprehensive data set and the most current Civil Rights Data Collection, serves as a follow-up to the previous brief. Authors Douglas Gagnon, Marybeth Mattingly, and Vincent Connelly report that, despite numerous states with revised policies related to seclusion and restraint in schools between 2009 and 2012, trends in the rates of restraint and seclusion of students with a disability in the United States remained relatively consistent between survey years. Low-poverty, low-minority districts are more likely to report high rates of restraint than are high-poverty, high-minority districts, although this trend in the most recent data is less pronounced than the trend found in the 2009−2010 data. In addition, restraint and seclusion are most common in cities and least common in rural places. The authors conclude that future research should examine the factors that lead to the use of restraint and seclusion in some schools, as well as what conditions lead to uptake of alternative approaches to managing challenging student behavior
Numerical analysis of four-wave mixing between 2 ps mode-locked laser pulses in a tensile-strained bulk SOA
A numerical model of four-wave mixing between 2-ps pulses in a tensile-strained bulk semiconductor optical amplifier is presented. The model utilizes a modified Schrodinger equation to model the pulse propagation. The Schrodinger equation parameters such as the material gain first and second order dispersion, linewidth enhancement factors and optical loss coefficient are obtained using a previously developed steady-state model. The predicted four-wave mixing pulse characteristics show reasonably good agreement with experimental pulse characteristics obtained using frequency resolved optical gating
Restraint and Seclusion of Students With a Disability Continue to Be Common in Some School Districts: Patterns Remain Relatively Consistent Despite Recent Policy Changes
In 2013, Carsey released a brief that analyzed rates of restraint and seclusion using a large, nationally representative data set of U.S. school districts. This brief serves as a follow-up to the previous brief, and its findings are particularly germane for two reasons. First, whereas all previous surveys of restraint and seclusion practices from the Civil Rights Data Collection (CRDC) surveys provided only representative samples, the most current survey was issued to all districts in the United States. Therefore, we were able to analyze a more comprehensive data set approximately twice the size of the one used in the 2013 brief. Second, approximately one-half of U.S. states updated their policies on restraint and seclusion between the 2009–2010 and 2011–2012 CRDC surveys,as lawmakers and civil rights advocates are increasingly questioning the use of restraint and seclusion in schools. Therefore, it is plausible that the frequency of restraint and seclusion in schools could have changed considerably during this time
RRS James Cook Cruise JC180 25 April - 30 May 2019. Strategies for the Environmental Monitoring of Marine Carbon Capture and Storage, STEMM-CCS
JC180 is the main experimental cruise component of the EC funded €16m project Strategies for the environmental monitoring of marine carbon capture and storage STEMM-CCS. The overall goals of the STEMM-CCS project are to develop techniques and methods to constrain potential leakage pathways for CO2 should it be stored in reservoirs and to develop techniques to detect and quantify CO2 release from the seabed should it leak from storage reservoirs in the future if they are developed on a commercial scale in the North Sea. This cruise, and the whole project aims to increase the confidence the science community and the public have as we move towards using old hydrocarbon reservoirs for CO2 storage to mitigate climate change. If we use these storage sites we need to ensure that should they leak we will be able to detect any leakage and quantify it
Marine baseline and monitoring strategies for Carbon Dioxide Capture and Storage (CCS)
The QICS controlled release experiment demonstrates that leaks of carbon dioxide (CO2) gas can be detected by monitoring acoustic, geochemical and biological parameters within a given marine system. However the natural complexity and variability of marine system responses to (artificial) leakage strongly suggests that there are no absolute indicators of leakage or impact that can unequivocally and universally be used for all potential future storage sites. We suggest a multivariate, hierarchical approach to monitoring, escalating from anomaly detection to attribution, quantification and then impact assessment, as required. Given the spatial heterogeneity of many marine ecosystems it is essential that environmental monitoring programmes are supported by a temporally (tidal, seasonal and annual) and spatially resolved baseline of data from which changes can be accurately identified. In this paper we outline and discuss the options for monitoring methodologies and identify the components of an appropriate baseline survey
Developments in marine pCO2 measurement technology; towards sustained in situ observations
The oceanic uptake of anthropogenic CO2 causes pronounced changes to the marine carbonate system. High quality pCO2 measurements with good temporal and spatial coverage are required to monitor the oceanic uptake, identify regions with pronounced carbonate system changes, and observe the effectiveness of CO2 emission mitigation strategies. There are currently several instruments available, but many are unsuitable for autonomous deployments on in situ platforms such as gliders, moorings and Argo floats. We assess currently available technology on its suitability for in situ deployment, with a focus on optode technology developments.
Optodes for pCO2 measurements provide a promising new technological approach, and were successfully calibrated over the range of 280–480 μatm applying modified time-domain dual lifetime referencing. A laboratory precision of 0.8 μatm (n = 10) and a response time (τ90) of 165 s were achieved, and with further development pCO2 optodes may become as widely used as their oxygen counterparts
Talc-dominated seafloor deposits reveal a new class of hydrothermal system
The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13?km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, hydrothermal precipitates at the VDVF comprise 85–90% by volume of the magnesium silicate mineral, talc. Hydrothermal fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215?°C with low metal concentrations, intermediate pH (5.8) and high concentrations (667?mmol?kg?1) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487±101?MW, comparable to the most powerful magma-driven hydrothermal systems known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models
Behaviour of chromium isotopes in the eastern sub-tropical Atlantic Oxygen Minimum Zone
Constraints on the variability of chromium (Cr) isotopic compositions in the modern ocean are required to validate the use of Cr isotopic signatures in ancient authigenic marine sediments for reconstructing past levels of atmospheric and ocean oxygenation. This study presents dissolved Cr concentrations (CrT, where CrT = Cr(VI) + Cr(III)) and Cr isotope data (δ53Cr) for shelf, slope and open ocean waters within the oxygen minimum zone (OMZ) of the eastern sub-tropical Atlantic Ocean. Although dissolved oxygen concentrations were as low as 44–90 μmol kg−1 in the core of the OMZ, there was no evidence for removal of Cr(VI). Nonetheless, there was significant variability in seawater δ53Cr, with values ranging from 1.08 to 1.72‰. Shelf CrT concentrations were slightly lower (2.21 ± 0.07 nmol kg−1) than in open ocean waters at the same water depth (between 0 and 160 m, 2.48 ± 0.07 nmol kg−1). The shelf waters also had higher δ53Cr values (1.41 ± 0.14‰ compared to 1.18 ± 0.05‰ for open ocean waters shallower than 160 m). This is consistent with partial reduction of Cr(VI) to Cr(III), with subsequent removal of isotopically light Cr(III) onto biogenic particles. We also provide evidence for input of relatively isotopically heavy Cr from sediments on the shelf. Intermediate and deep water masses (AAIW and NADW) show a rather limited range of δ53Cr values (1.19 ± 0.09‰) and inputs of Cr from remineralisation of organic material or re-oxidation of Cr(III) appear to be minimal. Authigenic marine precipitates deposited in deep water in the open ocean therefore have the potential to faithfully record seawater δ53Cr, whereas archives of seawater δ53Cr derived from shelf sediments must be interpreted with caution
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