Montana Kaimin, October 19, 1972

Student newspaper of the University of Montana, Missoula.https://scholarworks.umt.edu/studentnewspaper/7140/thumbnail.jp

The Pacifican, November 7, 1975

https://scholarlycommons.pacific.edu/pacifican/2253/thumbnail.jp

A study of functional equivalence in rats using class-specific reinforcers and olfactory stimuli

Functional equivalence has been demonstrated in some non-human animals using a repeated reversal simple discrimination procedure. The current study addressed the issue of stimulus equivalence in rats using a repeated reversals procedure with class-specific reinforcers and olfactory stimuli. Four Holtzman Sprague-Dawley rats were tested to establish functional classes using scented sand as olfactory stimuli in a two-choice modified operant chamber and an odor arena. Stimuli were randomly assigned to one of two sets, and at any given point, one set was designated as positive and one was negative. Responses to the positive set were reinforced until criterion levels of performance at 90% or higher for two consecutive sessions were reached, at which point the contingencies were reversed. Reversals continued throughout multiple testing phases as criterion was reached. The results of the study showed that one subject demonstrated clear evidence of functional classes. That is, after encountering a few reversed stimuli on the first day of a given reversal, correct responses were made to the remainder of the stimuli within that class without explicit reinforcement. However, evidence for functional classes was much less clear for the other subjects in the study. The variables that allowed for one subject to provide evidence and not the others remains unclear and further research using rats and olfactory stimuli needs to be done to assess the differences in outcomes seen in the present study

The Trail, 2010-11-05

https://soundideas.pugetsound.edu/thetrail_all/1626/thumbnail.jp

Chinese-character crowding—I. Effects of structural similarity

Crowding impedes the identification of flanked objects in peripheral vision. Prior studies have shown crowding strength decreases with target–flanker similarity. Research on crowding in Chinese-character recognition has been scarce in the literature. We aimed to fill the research gap by examining the effects of structural similarity on Chinese-character crowding. Regularity in within-character configuration, i.e., orthographic legality, of flankers was manipulated in Experiment 1. Target–flanker similarity in orthographic legality did not affect crowding strength, measured as contrast threshold elevation. Crowding weakened only when the strokes in the flankers were scrambled. Contour integrity of flankers was manipulated by randomly perturbing the phase spectra of the stimulus images in Experiments 2a and 2b. Crowding by perturbed-phase flankers remained robust but was weaker compared with intact-phase flankers. Target–flanker similarity in contour integrity modulated crowding strength. Our findings were consistent with the postulation that faulty integration of low-level visual features contributed to crowding of Chinese characters. Studies on Chinese-character recognition and crowding can provide important insights into how the visual system processes complex daily objects.published_or_final_versio

The Montana Kaimin, April 9, 1929

Student newspaper of the University of Montana, Missoula.https://scholarworks.umt.edu/studentnewspaper/2151/thumbnail.jp

Using the Lyman-α forest to determine the power spectrum of mass density perturbations

I present an analysis of techniques used to determine the mass power spectrum from observations of the intergalactic medium.Simple Monte Carlo simulations are presented which clarify some of the problems which must be overcome when attempting any inversion process. The 1 dimensional flux power spectrum is dependent on both the clustering of the absorption features and on the scaling relations existing between the dark matter and baryon distributions.More realistic simulated spectra are used to illustrate differences in the mean flux power spectrum for a range of cosmologies and the ratio of the 1 dimensional linear mass and flux power spectra. The mass distribution is much more dependent on cosmological parameters than the flux power spectrum, highlighting the very accurate measurements of the latter quantity required for an accurate recovery of the mass density power spectrum.These spectra are further analysed by deconvolution into Voigt profiles. This technique is shown to be an excellent approximation, in spite of the current cosmic web paradigm of the Ly-a forest. However the power spectrum of the positions of these fitted lines is shown to be a very poor indicator of the underlying mass density field.Inferring the 3 dimensional forms of power spectra from 1 dimensional data is shown to be problematic. This, coupled with analysis of the correlation matrix of the flux power spectrum, casts doubts on the reliability of the error analysis presented in the literature

The Pacifican, May 1,1997

https://scholarlycommons.pacific.edu/pacifican/1674/thumbnail.jp

House price momentum and strategic complementarity

House prices exhibit substantially more momentum, positive autocorrelation in price changes, than existing theories can explain. I introduce an amplification mechanism to reconcile this discrepancy. Sellers do not set a unilaterally high or low list price because they face a concave demand curve: increasing the price of an above-average-priced house rapidly reduces its sale probability, but cutting the price of a below-average-priced house only slightly improves its sale probability. The resulting strategic complementarity amplifies frictions because sellers gradually adjust their price to stay near average. I provide empirical evidence for concave demand using a quantitative search model that amplifies momentum two- to threefold