10,898 research outputs found
Citizen Mobilization and Community Institutions: the Public Education Network's Policy Initiatives - Executive Summary
The executive summary for a report that analyzes the results of a bold set of initiatives designed to stimulate and support public responsibility for public education in 14 locales around the country. Local education funds (LEFs) led these initiatives, which received support from the Annenberg Foundation through the LEFs' national organization, the Public Education Network (PEN). In each of the three initiatives, the LEFs were expected to lead a process of community engagement in one area of local education policy: equipping students to meet the standards set forth in accountability systems; improving teaching quality; or strengthening school-community ties
Electroconvective instability with a stabilizing temperature gradient. 2 - Experimental results
Threshold voltage measurements on electric field instability in fluid with stabilizing temperature gradien
Costs of Participation in the School Administration Manager (SAM) Process
Analyzes variations in school districts' implementation costs, by model, of the school administration manager process to help principals increase the time they spend on instructional leadership. Explores funding sources
CSM docked DAP/orbital assembly bending interaction-axial case
A digital autopilot which can provide attitude control for the entire Skylab orbital assembly using the service module reaction control jets is described. An important consideration is the potential interaction of the control system with the bending modes of the orbital assembly. Two aspects of this potential interaction were considered. The first was the possibility that bending induced rotations feeding back through the attitude sensor into the control system could produce an instability or self-sustained oscillation. The second was whether the jet activity commanded by the control system could produce excessive loads at any of the critical load points of the orbital assembly. Both aspects were studied by using analytic techniques and by running simulations on the all-digital simulator
Electrohydrodynamic Rayleigh-Taylor bulk instability
Stability criterion for initially static, stratified fluid subject to electrical stres
Measurement of solar UVB exposures in sea water with a high exposure dosimeter
For several decades, marine scientists have investigated the underwater ultraviolet light environment using a wide variety of spectroradiometric and radiometric equipment. These types of instruments are extremely useful for taking underwater measurements of the solar UV within a short window of time, for example recording fluctuations in UV levels caused by rapidly changing environmental parameters, like cloud cover or water turbidity. However, over long phases these spectroradiometers and radiometers become increasingly problematic to use, with high amounts of maintenance time necessary involving routine calibrations and corrections for the immersion effect.
However, to supplement the short ā term underwater measurements using spectroradiometers and radiometers, a new long ā term dosimetric system employing Poly (2,6-dimethyl-1, 4-phenylene oxide) (PPO) film has been developed. The PPO film dosimeter has proven to be capable of measuring underwater UV dosages of at least five times that of the more commonly used polysulphone dosimeter, at a level of accuracy close to what would be expected of dosimetric measurements made in air provided that the necessary calibrations are completed correctly.
This presentation details a measurement campaign made in a simulated sea water
environment using a batch of PPO dosimeters set at different depths and aligned to a range of different inclinations and azimuths by means of attachment to a custom built dosimeter submersible float (DSF) unit. The results obtained from this measurement campaign were used to compute a diffuse attenuation coefficient (Kd) for the sea water. This Kd value was compared to a Kd value derived from results taken using a radiometer in the same water
UV protection and shade structures
[Abstract]: Broadband field measurements were conducted beneath three different sized public shade structures at a sub-tropical Southern Hemisphere site for relatively clear skies and for a changing solar zenith angle (SZA) of 13o to 76o. These data were compared to the diffuse UV to quantify the relationship between diffuse UV and the UV in the shade of the structures. On the horizontal plane, the ultraviolet protection factors (UPF) for the shade structures ranged from 1.5 to 18 for a decreasing SZA. The data from this research is significant, because it shows that as the SZA of the sun increases so does the relative proportion of scattered UV beneath the shade structures which in turn decreases the shade structures UPF. In Australia, erythemal UV in full sun can reach levels of approximately 2.5 MED/h or more in the middle of the day during winter. Therefore, it is necessary for people that live in similar latitudes to minimise UV exposure in all climatic conditions throughout the year. Based on this research, a standard for reporting the UV protection provided by shade structures is essential for the public to make an informed decision on the efficacy of particular structures in reducing personal UV exposure
Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
Peculiar velocity measurements are the only tool available in the
low-redshift Universe for mapping the large-scale distribution of matter and
can thus be used to constrain cosmology. Using redshifts from the 2M++ redshift
compilation, we reconstruct the density of galaxies within 200 Mpc/h, allowing
for the first time good sampling of important superclusters such as the Shapley
Concentration. We compare the predicted peculiar velocities from 2M++ to
Tully-Fisher and SNe peculiar velocities. We find a value of , suggesting
, in good
agreement with other probes. The predicted peculiar velocity of the Local Group
arising from the 2M++ volume alone is km/s, towards , only out of alignment with the Cosmic Microwave
Background dipole. To account for velocity contributions arising from sources
outside the 2M++ volume, we fit simultaneously for and an external
bulk flow in our analysis. We find that an external bulk flow is preferred at
the 5.1 level, and the best fit has a velocity of km/s
towards . Finally, the predicted bulk flow of a 50
Mpc/h Gaussian-weighted volume centred on the Local Group is km/s,
in the direction , in agreement with predictions
from CDM.Comment: 17 pages. MNRAS, in press. Density and peculiar velocity grids
available at http://cosmicflows.uwaterloo.ca or http://cosmicflows.iap.f
Implementation of the National SAM Innovation Project: A Comparison of Project Designs
Compares increases in principals' instructional time and other benefits of hiring school administration managers specifically for the position to help principals with time management and of assigning the task to those who hold other school positions
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