Thesis (Ph. D.)--University of Washington, 1992. / Vita. Includes bibliographical references (leaves [210]-240).

Thesis (doctoral)--Rijksuniversiteit te Utrecht.

Thesis (doctoral)--Rijksuniversiteit te Utrecht.

The present study examined the effects of engagement in both low-preferred and high-preferred concurrent activities during self-control training, and determined the activities' differential effects on participants' tolerance to delayed reinforcement. Three children with autism were given a choice between a small immediate reinforcer and a large delayed reinforcer. During baseline, all three participants consistently selected the smaller reinforcer, and the immediate choice. Two training conditions, including a progressive delay to reinforcement with either a preferred or non-preferred concurrent activity, were first alternately and then simultaneously presented. Two of the three participants reversed response allocation from 100% for the sooner smaller reinforcer to over 90% for the larger later reinforcer, and maintained almost exclusive allocation for the preferred activity. All three participants increased delay tolerance by at least 250% of average natural baseline duration.

AN ABSTRACT OF THE THESIS OF Katelyn Louise Decker, Master of Science Degree in Behavior Analysis and Therapy, presented on April 30, 2015, at Southern Illinois University TITLE: EFFECTS OF GAMBLING OUTCOMES ON LEVEL OF IMPULSIVITY MAJOR PROFESSOR: Dr. Mark R. Dixon The effects of exposure to winning and losing gambling outcomes on levels of impulsivity among non-gamblers were investigated in a within-subjects experimental design with randomization of treatment phases. Participants included 20 non-gamblers (10 male, 10 female), 18 years or older, selected from a sample of 40 volunteers who completed the South Oaks Gambling Screen (Lesieur & Blume, 1987) and received a score of 0, indicating no predictors of potential pathological gambling. Dependent measures of levels of impulsivity were recorded using an abbreviated version of the delayed discounting questionnaire described by Dixon et al. (2003). Derived k-values were calculated by fitting indifference points at each delay to the hyperbolic equation proposed by Mazur (1987) and average k-value was calculated for each participant across delays. Participants were exposed to both winning and losing outcomes by completing 25 trials within a slot-machine task programmed in Microsoft Visual Basic Express Edition 2008 (Maclin, et al., 2006, p. 127-154). Results were subjected to statistical analysis to determine whether a statistically significant, functional relationship existed between increases and decreases in level of impulsivity (k-value) in comparison to baseline. Across all participants, regardless of order of experimental conditions, results indicated a more than 26% decrease (-82.20-3133.33) in level of impulsivity (0-2.1694) following a losing outcome and a more than 24% decrease (-89.95-3300) in level of impulsivity (0-2.1694) following a winning outcome in comparison to baseline (0-2.3056). Results are consistent with the hypothesis that exposure to winning outcomes decrease impulsivity, but inconsistent with the hypothesis that exposure to losing outcomes increase impulsivity. Historical perspectives of pathological gambling, social impacts of gambling disorder, and trait and state-dependent perspectives of impulsivity are discussed. Potential implications for further research using delayed discounting measures are provided, as well as potential limitations of the present study. Keywords: gambling, impulsivity, delayed discounting, slot-machine, outcomes

Flowers, the sole natural source of pollen and nectar for bees, present many similar features, in colour, shape, size and scent, which facilitate pollinator attraction. This similarity among stimuli requires perception of commonality but also a capacity for differentiation between similar but different stimuli. While many flowers of a similar type will elicit approach and foraging, failure to access resources on any individual flower in an array (e.g. due to depletion) will not necessarily generalize and deter further foraging. Such conditions demand that bees respond to both the similarity and differences among stimuli which may share many common features but differ individually in available resources. Two questions are raised by this challenge and will herein be addressed: how do bees perceive and respond to ‘similar but different’ stimuli? And, how do bees use such cues to find rewarding flowers? Picture-object correspondence has not been previously specifically studied in invertebrates. The correspondence between picture-cue and object stimuli may offer a unique opportunity to trigger memory for corresponding targets while still retaining an important distinction between unrewarding cue and rewarding targets. Perception of pictures is not always perceived by animals as either the same as or equivalent to the intended subject. According to Fagot et al. (2000) the perceived relationship may result in confusion, independence or equivalence and is dependent upon experience. The objectives of this thesis are twofold: first, determine how bumblebees (Bombus impatiens) perceive the relationship between objects and corresponding pictures and secondly, to determine whether or not bees may be able to attend to and use pictures as cues while foraging. The correspondence of picture and object by bees was evaluated with four experiments of preference: (1) learned differentiation; spontaneous association to (2) colour, and (3) achromatic, impoverished images; and (4) learned picture cue use. Firstly, results show that bees do not confuse an object with a corresponding picture but nevertheless do perceive a relationship between them if colour cues are retained. Altered, achromatic images were not consistently treated as corresponding to coloured objects. Secondly, bees can learn to use a picture cue in a delayed matching foraging task. Results further suggest a role of three contributing factors in bumblebee picture cue use: (i) conditions of high inconsistency as to which target will be rewarding; (ii) stable target locations; and (iii) individual foraging experience. It appears that bumblebees can learn to use cues, in a delayed matching task, when the location of the corresponding target is known and stable, the individual bee has acquired some experience in successful foraging, and reward is otherwise unpredictable without the use of the cue. Bees may disregard secondary cues as noise under conditions of high target predictability whereby floral constancy or target perseveration may be most efficient, but attend to and learn such cues as signals if target reward is highly unpredictable. The conditions for this sensitivity may coincide with naturally occurring floral cycles.

An epidemiological survey of Valley Fever (coccidioidomycosis) was conducted in dogs in Tucson and Phoenix. Dogs were tested for delayed type hypersensitivity (DTH) using coccidioidin, a reagent that is not commercially available and results of the skin tests were compared with corresponding serologic test results.

Dogs in the Tucson area with a known history of clinical Valley Fever were tested with two skin test reagents to determine their ability to detect delayed type hypersensitivity (DTH) to the Coccidioides spp. The reagents used were Spherusol, from Nielsen Biologicals, and coccidioidin, which is no longer commercially available. Skin tests were read 48 hours after placement and evaluated for erythema and/or induration.

<p> Fission-product bromine was isolated from a uranium target by the hot-atom reaction of the fission recoils with methane to form organic bromides. The organically-bound bromine was shown to be formed preferentially by primary (independently-formed) bromine with little contribution from secondary bromine. </p> <p> The delayed-neutron activity of the short-lived bromine isotopes was analyzed to obtain the relative yields of delayed neutrons from Br8?, Br88 and Br89 produced as primary fission products. The relative delayed-neutron yields are summarized below. (see abstract in text) </p> / Thesis / Doctor of Philosophy (PhD)

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