Response to actual and simulated recordings of conventional takeoff and landing jet aircraft

Comparability between noise characteristics of synthesized recordings of aircraft in flight and actual recordings were investigated. Although the synthesized recordings were more smoothly time-varying than the actual recordings and the synthesizer could not produce a comb-filter effect that was present in the actual recordings, results supported the conclusion that annoyance response is comparable to the synthesized and actual recordings. A correction for duration markedly improved the validity of engineering calculation procedures designed to measure noise annoyance. Results led to the conclusion that the magnitude estimation psychophysical method was a highly reliable approach for evaluating engineering calculation procedures designed to measure noise annoyance. For repeated presentations of pairs of actual recordings, differences between judgment results for identical signals ranged from 0.0 to 0.5 db

A study of noise metric and tone correction accuracy

Methods currently used to measure human response to aircraft flyover noise were investigated. Response to high level aircraft noise usually experienced outdoors was obtained. Response to aircraft flyover noise typical of indoor exposure was also investigated. It was concluded that current methods for evaluating response to aircraft flyover are more accurate for outdoor noise

Are walkable neighbourhoods possible in urban Oman?

This is the third post of a 3-part series on urbanisation, public open spaces and physical activity in Oman

Muscat: Concrete jungle or oasis by the sea?

This is the second post of a 3-part series on urbanisation, public open spaces and physical activity in Oman

What are public open spaces?

This is the second post of a 3-part series on urbanisation, public open spaces and physical activity in Oman

NCLB: Local implementation and impact in southwest Washington state.

The research reported here is from the first two years of an ongoing and largely qualitative study to examine the impact of the No Child Left Behind federal education policy on educational practice and climate in elementary schools in two districts in southwest Washington. Based on systematic drop-in observations in classrooms and interviews with teachers and school and district administrators, data indicated that the policy had partially yielded the intended standards-based reforms but at considerable local cost. While most participating administrators described efforts to use NCLB to leverage needed change, most teachers described struggles to sustain best practice and to avoid some negative consequences to their students and schools. Administrators anticipated that resistant teachers would be nudged from the profession, and the greatest attrition among participating teachers was from the fourth-grade level at which the state’s standards-based test was administered. Fourth-grade teachers particularly expressed concern about test-related stress and test-driven curricula interfering with children’s individual needs and with their own ability to provide developmentally appropriate instruction adapted for their particular students. The validity and utility of test results was a local issue

Mother Nature

A surrealistic piece that represents Mother Nature. Acrylic paint on a 11 x 14 canvas

Effects of Cattle Grazing on Woodlands in Central Iowa

Iowa\u27s forests have undergone a dramatic decline in area since settlement by Europeans. Most of the remaining forests have been degraded by an assortment of human impacts, with cattle grazing the most prominent among them. Using a matched pairs study designed to control for environmental differences among plots, I examined the impact of cattle grazing on the forest understory, canopy trees, and tree regeneration. There were distinct groups of understory species associated with ungrazed and grazed plots. Species associated with ungrazed plots were all native and tended to be perennial herbs with fleshy roots. Ungrazed plots also had species preferring moist forests with closed canopies, habitats lacking human disturbance, and with ranges restricted to the eastern United States. In contrast, 30% of species associated with grazed plots were exotic, and the species associated with these sites were more likely to be annuals, have fibrous toots, occur in a wide variety of habitats, and have a cosmopolitan distribution. There were fewer seedlings found in grazed compared to ungrazed woods, and for canopy trees and seedlings, there was evidence for species specific responses to grazing. Woods that have been grazed, but not to the point of canopy loss and sod formation, are representative of the majority of the remaining woods in Iowa; thus, the results of this study are relevant to understanding the dynamics of Iowa forests and to developing plans for their restoration

Condition and food availability to Pacific sand lance (Ammodytes hexapterus) in Prince William Sound, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2000Pacific sand lance (Ammodytes hexapterus) is a common forage fish for seabirds in Prince William Sound, Alaska (PWS). The objectives of this study were to determine if condition of young-of-the-year (YOY) sand lance varies within PWS, and if variation in condition is related to temperature and food availability. Fish were collected in 1996, 1997, and 1998 and assayed for energy content. Zooplankton samples were collected concurrently. SeaWiFS ocean color satellite images and AVHRR temperature images were analyzed for chlorophyll biomass and temperature history. Standard lengths of YOY sand lance ranged from 47 to 97 mm, and their energy content ranged from 4490 to 5670 cal/g, with significant differences among stations. Sand lance in southern PWS were in better condition than those in other areas. Surface chlorophyll concentration and zooplankton abundance were not related to energy content; however, there was a positive and significant relationship between energy content and SST

Solar Wind Helium, Neon, And Argon In Genesis Aluminum Collectors

The Genesis mission collected samples of solar wind: SW) for 853 days and returned them to Earth for analysis. There are several processes that have the potential to significantly alter the composition between the time when SW ions are accelerated away from the sun, to the time the laboratory measurements are made. This work attempts to constrain these sources of fractionation and present the best estimate of the isotopic composition of SW helium, neon, and argon implanted into two different aluminum SW collectors on board the Genesis Mission. We have conducted a diffusion experiment on a similar time scale as the Genesis mission to determine the diffusion parameters of the two different aluminum collector materials and to quantify the changes in the measured ratios due to diffusive losses for the light noble gases. The results of this experiment show that the polished Al collector is not sufficiently retentive of the light noble gases to be a reliable collector for the light gases, but that the composition of the light gases implanted in the Al on sapphire collector does not show a measurable effect due to thermal diffusion. The Genesis mission collected separate samples of different types: `regimes\u27) of SW: low-speed, high-speed, and coronal mass ejections. Compositional differences between the different SW regimes: especially the low-speed and high-speed SW) are thought to provide a measure of possible fractionation during the acceleration of the SW. By making high-precision isotopic measurements on collectors of the three SW regimes, we have put strict upper limits on the difference between the low-speed and high-speed SW regimes: 20Ne/22Ne \u3c 0.24 ± 0.37% and 36Ar/38Ar \u3c 0.11 ± 0.26%. And we have made isotopic measurements of the light noble gases of the bulk SW: without selective collection of different SW regimes) from the aluminum collectors. Accounting for the sources of fractionation discussed above, I propose the following as the best current bulk SW isotopic values: 20Ne/22Ne = 13.75 ± 0.02, 21Ne/22Ne = 0.0329 ± 0.0002, and 36Ar/38Ar = 5.501 ± 0.005: all errors are 1σ)