1,894 research outputs found
Equitable Access in Education: Access to Joy, Choice Options, and Strong Neighborhood Schools
The purpose of this co-authored dissertation was to understand equitable access of quality educational opportunities in St. Louis, Missouri. Through the following research, we present a better understanding of equity and access in education from a classroom level, on a school level, and finally, on a regional level. This collection of research is the effort of a group of committed and concerned educators seeking to understand the ways of making quality education accessible for all families, specifically in the areas of school choice, quality neighborhood schools, and play in the classroom. By equitable access, we mean all families being able to participate in and take advantage of appropriate learning opportunities that they need or that are desired. Hollenkampās mixed methods research asked the question of how an increase in play and experiential education would impact early childhood learners both academically and social-emotionally and found that students who had opportunities to play at school grew at the same academic rate as peers who did not get to play while also showing higher levels of character development than their non-playing peers. Sandersā mixed methods research examined enrollment trends in a neighborhood school and the effect of marketing and promoting strategies that work to make the school the desired choice for families in the neighborhood and found definitive ways to attract and retain families in a neighborhood school among other choice options. Schuesslerās mixed methods research examined how school enrollment processes impact equitable access to school choice options for traditionally underserved populations and found a range in the complexity of enrollment practices across schools that resulted in certain choice options being more accessible to underserved families and other options being less accessible. The collective impact of this research has the potential to improve educational outcomes for students on a variety of levels
A second anniversary operational review of the OmniTRACS(R): The first two-way mobile Ku-band satellite communications system
A novel two-way mobile satellite communications and vehicle position reporting system that is currently operational in the United States and Europe is described. The system characteristics and service operations are described in detail. Technical descriptions of the equipment and signal processing techniques are provided
Measurements of Temperature Variations in the Atmosphere near the Tropopause with Reference to Airspeed Calibration by the Temperature Method
Measurements of temperature variations in the atmosphere near the tropopause over land in the vicinity of Langley Field, Va., are presented. This investigation was made for the purpose of obtaining information on the accuracy of the temperature method(NACA TN 2046) of airspeed calibration over the range of Mach number from 0.6 to .08. The temperature surveys and the description of a specially designed thermometer are also presented
THE BEHAVIOR OF ELECTROLYTIC SOLUTIONS AT ELEVATED TEMPERATURES AS DERIVED FROM CONDUCTANCE MEASUREMENTS
Methods and techniques for measuring the conductances of reactor solutions at elevated temperatures and to interpret the results with electrolytic solution theories are discussed. Criteria applied to room-temperature conductances for determining complete ionization of 1-1 electrolytes were applied to the Noyes high-temperature conductance data obtdined on NaCl, HCl, KCl, NaOH, AgNO3, and H/sub 3/PO/sub 4/ solutions. lt was found that the first four electrolytes behave as strong electrolytes up through temperatures of 218, 218, 281, and 156 deg C, respectively. Application of the Bjerrum theory showed that, somewhat above each of these temperatures, these electrolytes begin to associate by ion-pair formation. H/sub 3/PO/sub 4/ solutions associated at room temperature and above. AgNO/sub 3/ solutions appeared to asscciate at all temperatures. The equivalent conductances and infinite dilution and the dissociation constants for each of the electrolytes were calculatsd. An apparatus was constructed and measurements were made on the conductances of LiOH and NH/sub 4/OH solutions over the temperature range of 100 to 520 deg F. Equivalent conductances at infinite dilution were calculated. The pH of reactor coolants using LiOH or NH/sub 4/OH was calculated from the disscciation constants for water, LiOH, and NH/sub 4/OH at elevated temperatures. (auth
A Method of Calibrating Airspeed Installations on Airplanes at Transonic and Supersonic Speeds by the Use of Accelerometer and Attitude-Angle Measurements
A method is described for calibrating airspeed installation on airplanes at transonic and supersonic speeds in vertical-plane maneuvers in which use is made of measurements of normal and longitudinal accelerations and attitude angle. In this method all the required instrumentation is carried within the airplane. An analytical study of the effects of various sources of error on the accuracy of an airspeed calibration by the accelerometer method indicated that the required measurements can be made accurately enough to insure a satisfactory calibration
Window screening, ceilings and closed eaves as sustainable ways to control malaria in Dar es Salaam, Tanzania.
BACKGROUND\ud
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Malaria transmission in Africa occurs predominantly inside houses where the primary vectors prefer to feed. Human preference and investment in blocking of specific entry points for mosquitoes into houses was evaluated and compared with known entry point preferences of the mosquitoes themselves.\ud
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METHODS\ud
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Cross-sectional household surveys were conducted in urban Dar es Salaam, Tanzania to estimate usage levels of available options for house proofing against mosquito entry, namely window screens, ceilings and blocking of eaves. These surveys also enabled evaluation of household expenditure on screens and ceilings and the motivation behind their installation.\ud
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RESULTS\ud
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Over three quarters (82.8%) of the 579 houses surveyed in Dar es Salaam had window screens, while almost half (48.9%) had ceilings. Prevention of mosquito entry was cited as a reason for installation of window screens and ceilings by 91.4% (394/431) and 55.7% (127/228) of respondents, respectively, but prevention of malaria was rarely cited (4.3%, 22/508). The median cost of window screens was between US 301-400. The market value of insecticide-treated nets, window screening and ceilings currently in use in the city was estimated as 2, 5 and 42 million US$. More than three quarters of the respondents that lacked them said it was too expensive to install ceilings (82.2%) or window screens (75.5%).\ud
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CONCLUSION\ud
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High coverage and spending on screens and ceilings implies that these techniques are highly acceptable and excellent uptake can be achieved in urban settings like Dar es Salaam. Effective models for promotion and subsidization should be developed and evaluated, particularly for installation of ceilings that prevent entry via the eaves, which are the most important entry point for mosquitoes that cause malaria, a variety of neglected tropical diseases and the nuisance which motivates uptake
Climate Variability and Ross River Virus Transmission in Townsville Region, Australia 1985 to 1996
Background How climate variability affects the transmission of infectious diseases at a regional level remains unclear. In this paper, we assessed the impact of climate variation on the Ross River virus (RRv) transmission in the Townsville region, Queensland, north-east Australia. Methods Population-based information was obtained on monthly variations in RRv cases, climatic factors, sea level, and population growth between 1985 and 1996. Cross-correlations were computed for a series of associations between climate variables (rainfall, maximum temperature, minimum temperature, relative humidity and high tide) and the monthly incidence of RRv disease over a range of time lags. The impact of climate variability on RRv transmission was assessed using the seasonal auto-regressive integrated moving average (SARIMA) model. Results There were significant correlations of the monthly incidence of RRv to rainfall, maximum temperature, minimum temperature and relative humidity, all at a lag of 2 months, and high tide in the current month. The results of SARIMA models show that monthly average rainfall (Ī²=0.0012, p=0.04) and high tide (Ī²=0.0262, p=0.01) were significantly associated with RRv transmission, although temperature and relative humidity did not seem to have played an important role in the Townsville region. Conclusions Rainfall, and high tide were likely to be key determinants of RRv transmission in the Townsville region
Combining frequency and time domain approaches to systems with multiple spike train input and output
A frequency domain approach and a time domain approach have been combined in an investigation of the behaviour of the primary and secondary endings of an isolated muscle spindle in response to the activity of two static fusimotor axons when the parent muscle is held at a fixed length and when it is subjected to random length changes. The frequency domain analysis has an associated error process which provides a measure of how well the input processes can be used to predict the output processes and is also used to
specify how the interactions between the recorded processes
contribute to this error. Without assuming stationarity of the input, the time domain approach uses a sequence of probability models of increasing complexity in which the number of input processes to the model is progressively increased. This feature of the time domain approach was used to identify a preferred direction of interaction between the processes underlying the generation of the activity of the primary and secondary endings. In the presence of fusimotor activity and dynamic length changes imposed on the muscle, it was shown that the activity of the primary and secondary endings carried different information about the effects of the inputs imposed on the muscle spindle. The results presented in this work emphasise that the analysis of the behaviour of complex
systems benefits from a combination of frequency and time
domain methods
Joint analysis of stressors and ecosystem services to enhance restoration effectiveness
With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments. www.pnas.org/lookup/suppl/doi:10.1073/pnas.1213841110/-/DCSupplementa
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