This study attempted to selectively stimulate and record from either the amphibian or basilar papillae of Rana pipiens. Computer-generated, frequency-specific clicks were used to elicit BSER's from either amphibian or basilar papillae. Narrowband noise fatiguers were presented in the frequency region of which each papillae are tuned. It was expected that a threshold shift would be elicited in the papillae that received the acoustic trauma, and that no threshold shift would be observed from the collateral papilla. The results of this experiment indicated that there was no overall difference between the threshold shift of either papilla. Furthermore, the amount of AP threshold shift was relatively constant regardless of whether the fatiguer bandwidth was overloading the amphibian or basilar papillae. By contrast, the amount of BP threshold shift was greater when proceeded by a fatiguer with a bandwidth corresponding to the BP tuning region than by a fatiguer with a bandwidth corresponding to the AP tuning region. Additionally, curare maximized the amount of BP threshold shift following fatiguing noise presented with a bandwidth to which the AP is tuned.

Military jet over-flight activities pose a potential threat to staging waterfowl and pilots. The migration period is important for nutrient acquisition and courtship as these waterfowl enter the breeding season. Using a focal animal (continuous) technique for five-minute intervals, diurnal Time/Activity (TA) budgets for Canada Geese (Branta canadensis canadensis) (n=751), American Black Duck (Anas rubripes) (n=474) and Common Goldeneye (Bucephala clangula) (n=1274) were compiled during 216 hours of behavioural observation. The study was conducted from 26 April to 27 May, 2002 at the outlet of Lac Fourmont, Labrador (52° 03' 30"N, 60° 31' 01" W), in an ashkui or area of open water in an otherwise frozen landscape, which is known historically as a place to hunt waterfowl. These staging grounds are within the 130 000 km2 Low-level Training Area (LLTA) of the Quebec-Labrador Peninsula. Generalized Linear Modeling (GLM) of ranked variables was used to analyze behaviour by: observer, sex, pair status, time of day, date, and each weather parameter. Male Common Goldeneye spent more time in courtship behaviours (2.7%) than females (1.1%) and they spent most of the daylight hours feeding (males 53.3% and females 54.5%), with little time resting (4.8% and 5.2%, respectively). In contrast, Black Ducks and Canada Geese spent relatively little time feeding (12.4% and 5% respectively) and most of their time sleeping (35% and 38% respectively) and locomotion (37.8% and 11% respectively). Ashkui are important to Common Goldeneyes for foraging, and to Canada Geese and Black Ducks for resting prior to the breeding season. / Ninety-one low-level jet over-flights occurred and sound levels (n=336 h) at the study site were measured. Effects of low-level jet over-flights were analyzed using GLM of ranked variables in order to analyze a number of variables simultaneously. All behavioural observations that occurred in the quarter hour periods up to 165 minutes after an over-flight were analyzed. Alert and courtship behaviours of Canada Geese increased after over-flights. Other behaviours were negatively affected to a lesser degree. Locomotor activities by Black Ducks increased significantly immediately following over-flights with a stronger movement response with increased noise. Increases in agonistic and comfort behaviours of Common Goldeneye were detected following over-flights with few other significant affects on their behaviour. / Key words. Anas rubripes, Branta canadensis, Bucephala clangula, disturbance, jet aircraft, Labrador, low-level flying, military activity, noise, spring staging, time-activity budgets, waterfowl

No description available.

Low-frequency noise has been measured on commercial power MOSFETs. These devices, fabricated with the VDMOS structure, exhibit a 1/f type noise spectrum. The interface state density obtained from noise measurements was compared with that obtained from the subthreshold-slope method. Reasonable agreement was found between the two measurements. The radiation effects on the noise power spectral density were also investigated. The results indicated that the noise can be attributed to the generation of interface traps near the Si-SiO₂ interface. The level of interface traps generated by radiation was bias dependent. The positive gate bias gave rise to the largest interface-trap density.

Includes bibliographical references (leaves 151-163). Investigates the behaviour of the intensity noise in a multimode Nd:YAG laser. The collective modes of oscillation are excited by broadband ambient noise. Because the phase of the excitation is unknown, a cross spectral technique to measure the antiphase dynamics directly and form a picture of the intensity noise interference for two to five mode operation is developed. For three mode operation, the contributions of the longitudinal modes to collective modes is measured.

Includes bibliographical references. Electronic publication; full text available in PDF format; abstract in HTML format. Investigates the behaviour of the intensity noise in a multimode Nd:YAG laser. The collective modes of oscillation are excited by broadband ambient noise. Because the phase of the excitation is unknown, a cross spectral technique to measure the antiphase dynamics directly and form a picture of the intensity noise interference for two to five mode operation is developed. For three mode operation, the contributions of the longitudinal modes to collective modes is measured. Electronic reproduction.[Australia] :Australian Digital Theses Program,2001. ix, 163 leaves : ill., charts ; 30 cm.

Bibliography: leaves 154-156. / 156 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the construction of a low-power end pumped Nd:YAG laser and the subsequent theoretical and experimental investigation of the antiphase dynamics exhibited by the laser. The end pumped laser was modelled by extending the classical model of Tang Statz deMars to non-uniform pump along the active medium. The anomalous threshold behaviour of the laser, where modes with lower gain can supass modes with higher gain as the pump power increases, was accounted for. The antiphase dynamics were explored by modulating the pump power and measuring the transfer functions from this input to various outputs. The laser's response to various sources of noise was also studied. / Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, Discipline of Physics and Mathematical Physics, 2003?

In order to examine the potential impact of military jet overflights and other disturbances on productivity of peregrine falcons (Falco peregrinus), we observed behavioral reactions of peregrines to disturbances at nests along the Tanana River, Alaska during the 1995-1997 breeding seasons. Military jets conducted low-altitude flights over a sample of nests under observation in each year (experimental nests), while other nests were not intentionally overflown (reference nests). Other disturbances occurred at random. Animal noise monitors (ANMs), which collect and store data on noise disturbance levels, were deployed at each observed nest. A total of 878 above-threshold (��� 85 dB) overflights were recorded by the ANMs during the course of the study. A total of 401 close (defined as ��� 1000 m slant distance from the nest) overflights by subsonic F-16, F-15, A-10, Harrier, Jaguar, or Tornado jet aircraft were recorded during observations. Close overflights by military jets accounted for 63% of all observed potential disturbances at experimental nests; they accounted for 2.6% of all observed potential disturbances at reference nests. Other potential disturbances at reference nests included civilian fixed-wing aircraft (41%), boats (33%), avian predators (17%), helicopters (5%), and mammalian predators (1%). Peregrine falcons responded differently to animate and inanimate sources of disturbance, and responded most intensely and most frequently to other raptors, particularly conspecifics. Flight reactions were common, but not in response to inanimate sources. Among inanimate potential disturbances, falcons responded most intensely to boats (6% of reactions involved flight), and least intensely to helicopters (3%) and fixed-wing aircraft (2%). Intensity of reactions to military jets was indistinguishable from that to either boats or other aircraft. Intense behavioral responses (including flight reactions) to military jet overflights were rarely observed in this study, even at slant distances <500 m, and no intense behavioral responses were observed at slant distances >550 m. Peregrine falcon productivity (number of fledglings produced per nesting attempt) in the study area was within the normal range for Interior Alaska and the Tanana River. Dose of jet aircraft disturbance was not correlated with productivity. Productivity was, however, negatively correlated with reactivity of both individual falcons and mated pairs. Those falcons that responded more intensely to overflights tended to have lower productivity. The sensitivity of breeding peregrine falcons to low-altitude jet overflights is a better indicator of subsequent productivity than actual dose of overflights. This is likely a reflection of lower parental quality/investment among breeding pairs with high reactivity (i.e., younger, less experienced parents are less likely to be productive). / Graduation date: 1999

Graduation date: 1996

Understanding what psycho-physiological and behavioural factors influence aversiveness of sound in marine mammals is important for conservation and practical applications. The aim of this study was to determine predictors for impact of anthropogenic noise and to develop a target-specific predator deterrence system for use on fish farms. Three classes of stimuli were tested: 1.) grey seal underwater communication calls expected to be used in territorial defence, 2.) high duty-cycle moderately loud artificial sounds (some of which were based on models of unpleasantness for humans), 3.) brief, intense pulses designed to elicit the acoustic startle reflex. Communication calls had no deterrence effect but instead caused attraction responses. Tests with high duty-cycle artificial sounds showed that food-motivated animals habituate quickly, although sound exposure caused subtle changes in diving patterns over a longer time. Field trials using the same stimuli were used to determine avoidance thresholds but also indicated that sound features like ‘roughness’ play a role. The startle eliciting stimuli, however, had the most dramatic effects. To this stimulus most seals exhibited rapid flight responses, hauled out, sensitised and showed signs of fear conditioning. Startle thresholds were found to be 80-85 dB above the assumed hearing threshold. The data showed that startle thresholds are a crucial predictor for the occurrence of strong avoidance behaviour and suggests that the startle response evolved to increase an animal’s propensity for flight. Finally, a prototype predator deterrence system based on the startle sounds was developed to repel seals whilst not affecting toothed whales. In fish farm trials, seals were deterred at close ranges but local abundance of cetaceans did not change showing that it is possible to cause differential responses between species based on differences in their audiograms. The results are used to develop noise exposure criteria and to elucidate acoustic parameters that can be used to predict responses to anthropogenic noise.