D. Busby

Measurement of optical response of a detuned resonant sideband extraction gravitational wave detector

We report on the optical response of a suspended-mass detuned resonant sideband extraction (RSE) interferometer with power recycling. The purpose of the detuned RSE configuration is to manipulate and optimize the optical response of the interferometer to differential displacements (induced by gravitational waves) as a function of frequency, independently of other parameters of the interferometer. The design of our interferometer results in an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a radiation pressure induced optical spring at around 41 Hz. We have developed a reliable procedure for acquiring lock and establishing the desired optical configuration. In this configuration, we have measured the optical response to differential displacement and found good agreement with predictions at both resonances and all other relevant frequencies. These results build confidence in both the theory and practical implementation of the more complex optical configuration being planned for Advanced LIGO.

The effect of aerial application of Zectran on brain cholinesterase activity in forest songbirds.

The carbamate insecticide Zectran® (active ingredient [AI] mexacarbate) was applied aerially to two 300 ha blocks of coniferous forest, one at a dosage rate of 70 g AI/ha and the other at 140 g AI/ha. Brain cholinesterase (ChE) activity was determined in 372 exposed and control forest song-birds representing seven species. Brain ChE activity was similar among controls of all species studied. Among exposed birds, ChE activity was lowest in individuals from the high-dose block, although differences were not statistically significant. Warbler ChE activity showed a statistically significant relationship to dosage rates. Spray deposit was four times as great on the high-dosage block as on the low one. Zectran® provides a margin of safety to songbirds exceeding that of the organophosphorus insecticide fenitrothion which is currently used on a widespread operational basis against spruce budworm (Choristoneura fumiferana) in New Brunswick, Canada.

An interlaboratory comparison of data on brain cholinesterase activity in forest songbirds exposed to aerial application of zectran

Zectran® (4-dimethylamino-3,5-xylyl N-methyl-carbamate), a carbamate insecticide (active ingredient [AI] mexacarbate), was aerially applied to two 300 ha plots of coniferous forest at dosage rates of 70 and 140 g AI/ha, respectively. The brains of 288 birds collected from the treated areas and 84 birds from untreated areas were sagittally sectioned into approximately equal halves. Each of the laboratories participating in the study, the Forest Pest Management Institute (FPMI) and the Canadian Wildlife Service, Atlantic Region (CWS), assayed one half of each brain for cholinesterase (ChE) activity and the results were compared. The ChE estimates of the two laboratories on half brains from the same birds were poorly correlated (R=0.136, P<0.05) and differed significantly (P<0.00005). The reasons for this are uncertain. Despite the discrepancy in ChE estimates, however, separate statistical analysis of each data set produced the same general conclusion: the ChE response to Zectran® exposure was statistically significant but biologically unimportant. In both data sets, statistically significant ChE responses by niche and time since spraying were found. The dosage rate emitted from the airplane was a better predictor of ChE activity in the canopy niches than was volume deposited at ground level, but volume deposited was a more useful predictor for ground birds in most situations. These results are discussed in the context of a proposal to develop a reference file of normal brain ChE activities of common wildlife species.

Setting upper limits on the strength of periodic gravitational waves from PSR [Formula Presented] using the first science data from the GEO 600 and LIGO detectors

Data collected by the GEO600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsars gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsars equatorial ellipticity.