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Hogan, D. E., Zentall, T. R., & Pace, G. (1983). Control of pigeons' matching-to-sample performance by differential sample response requirements. Am J Psychol, 96(1), 37–49.
Abstract: Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice.
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Nallan, G. B., Pace, G. M., McCoy, D. F., & Zentall, T. R. (1983). The role of elicited responding in the feature-positive effect. Am J Psychol, 96(3), 377–390.
Abstract: Hearst and Jenkins proposed in 1974 that elicited responding accounts for the feature-positive effect. To test this position, pigeons were exposed to a feature-positive or feature-negative discrimination between successively presented displays--one consisted of a red and a green response key and the other consisted of two green response keys. There were four main conditions: 5-5 (5-sec trials, 5-sec intertrial intervals), 5-30, 30-30, and 30-180. Conditions 5-30 and 30-180 should produce the largest amount of elicited responding, and therefore the largest feature-positive effects. A response-independent bird was yoked to each response-dependent bird to allow direct assessment of the amount of elicited responding generated by each condition. Contrary to the predictions by Hearst and Jenkins's theory, response-dependent birds showed large feature-positive effects in each condition. The largest feature-positive effect was obtained in condition 5-5. Response-independent birds produced similar results, but manifested low response rates.
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Henning, J. M., & Zentall, T. R. (1981). Imitation, social facilitation, and the effects of ACTH 4-10 on rats' bar-pressing behavior. Am J Psychol, 94(1), 125–134.
Abstract: The effects of ACTH 4-10 on rats' imitation learning was examined during the acquisition and extinction of a bar-press response for water reinforcement. Rats were exposed to either a bar-pressing conspecific (OB), an experimentally naive conspecific (ON), or an empty box (OE) during bar-press acquisition. In a factorial design, each rat was then exposed to one of the same three conditions during extinction. An 80 mcg dose of ACTH 4-10 was administered to half of the rats in each group prior to observation. Performance differences during acquisition were generally small, but significant performance differences during extinction were found. Social facilitation was indicated by the finding that rats extinguished in the presence of a conspecific exhibited significantly greater resistance to extinction than rats extinguished in the presence of an empty box. An imitation effect was also found. Rats that observed a bar-pressing conspecific during both acquisition and extinction (group OB-OB) showed significantly greater resistance top extinction than did groups OB-ON, CB-OE, or OE-OE. There were no significant effects of the hormone, however, relative to saline controls.
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Nallan, G. B., Pace, G. M., McCoy, D. F., & Zentall, T. R. (1979). Temporal parameters of the feature positive effect. Am J Psychol, 92(4), 703–710.
Abstract: Trial duration and intertrial interval duration were parametrically varied between groups of pigeons exposed to a discrimination involving the presence vs. the absence of a dot. Half the groups received the dot as the positive stimulus (feature positive groups) and half the groups received the dot as the negative stimulus (feature negative groups). Faster learning by the feature positive birds (feature positive effect) was found when the trial duration was short (5 sec) regardless of whether the intertrial interval was short (5 sec) or long (30 sec). No evidence for a feature positive effect was found when the trial duration was long (30 sec) regardless of the length of the intertrial interval (30 sec or 180 sec). The results suggest that short trial duration is a necessary condition for the occurrence of the feature positive effect, and neither intertrial interval nor trial duration/intertrial interval ratio are important for its occurrence. The suggestion that mechanisms underlying the feature positive effect and autoshaping might be similar was not supported by the present experiment since the trial duration/intertrial interval ration parameter appears to play an important role in autoshaping but not the feature positive effect.
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Fulhorst, C. F., Hardy, J. L., Eldridge, B. F., Chiles, R. E., & Reeves, W. C. (1996). Ecology of Jamestown Canyon virus (Bunyaviridae: California serogroup) in coastal California. Am J Trop Med Hyg, 55(2), 185–189.
Abstract: This paper reports the first isolation of Jamestown Canyon (JC) virus from coastal California and the results of tests for antibody to JC virus in mammals living in coastal California. The virus isolation was made from a pool of 50 Aedes dorsalis females collected as adults from Morro Bay, San Luis Obispo County, California. The virus isolate was identified by two-way plaque reduction-serum dilution neutralization tests done in Vero cell cultures. Sera from the mammals were tested for antibody to JC virus by a plaque-reduction serum dilution neutralization method. A high prevalence of JC virus-specific antibody was found in horses and cattle sampled from Morro Bay. This finding is additional evidence for the presence of a virus antigenically identical or closely related to JC virus in Morro Bay and indicates that the vectors of the virus in Morro Bay feed on large mammals. A high prevalence of virus-specific antibody was also found in horses sampled from Marin and San Diego counties. This finding suggests that viruses antigenically identical or closely related to JC virus are geographically widespread in coastal California.
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McHugh, C. P. (1989). Ecology of a semi-isolated population of adult Anopheles freeborni: abundance, trophic status, parity, survivorship, gonotrophic cycle length, and host selection. Am J Trop Med Hyg, 41(2), 169–176.
Abstract: A population of adult Anopheles freeborni near Sheridan, CA was sampled daily during 13 August-7 September 1984. Data on abundance, trophic status, and gonotrophic age were recorded. Abundance and gonotrophic age data were analyzed to estimate daily survivorship and gonotrophic cycle length. Daily survivorship for unfed mosquitoes was estimated to be 0.72 with a gonotrophic cycle of 6 days duration. Daily survivorship for bloodfed mosquitoes was estimated to be 0.74 with a gonotrophic cycle of 4 days. The 2 day difference in gonotrophic cycles between unfed and bloodfed mosquitoes was the result of the period required for maturation and mating of teneral females. In 1986, an incage release of field-collected females estimated survivorship at 0.75 per day. Precipitin tests of 1,338 blood-engorged mosquito abdomens indicated that bovids, horses, rabbits, and canids comprised 92% of bloodmeals; no bloodmeals of human origin were detected.
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Hardy, J. L. (1987). The ecology of western equine encephalomyelitis virus in the Central Valley of California, 1945-1985. Am J Trop Med Hyg, 37(3 Suppl), 18s–32s.
Abstract: Reeves' concept of the summer transmission cycle of western equine encephalomyelitis virus in 1945 was that the virus was amplified in a silent transmission cycle involving mosquitoes, domestic chickens, and possibly wild birds, from which it could be transmitted tangentially to and cause disease in human and equine populations. Extensive field and laboratory studies done since 1945 in the Central Valley of California have more clearly defined the specific invertebrate and vertebrate hosts involved in the basic virus transmission cycle, but the overall concept remains unchanged. The basic transmission cycle involves Culex tarsalis as the primary vector mosquito species and house finches and house sparrows as the primary amplifying hosts. Secondary amplifying hosts, upon which Cx. tarsalis frequently feeds, include other passerine species, chickens, and possibly pheasants in areas where they are abundant. Another transmission cycle that most likely is initiated from the Cx. tarsalis-wild bird cycle involves Aedes melanimon and the blacktail jackrabbit. Like humans and horses, California ground squirrels, western tree squirrels, and a few other wild mammal species become infected tangentially with the virus but do not contribute significantly to virus amplification.
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Sabattini, M. S., Monath, T. P., Mitchell, C. J., Daffner, J. F., Bowen, G. S., Pauli, R., et al. (1985). Arbovirus investigations in Argentina, 1977-1980. I. Historical aspects and description of study sites. Am J Trop Med Hyg, 34(5), 937–944.
Abstract: This is the introductory paper to a series on the ecology of arboviruses in Argentina. Epizootics of equine encephalitis have occurred since at least 1908, principally in the Pampa and Espinal biogeographic zones, with significant economic losses; human cases of encephalitis have been rare or absent. Both western equine and eastern equine encephalitis viruses have been isolated from horses during these epizootics, but the mosquitoes responsible for transmission have not been identified. A number of isolations of Venezuelan equine encephalitis (VEE) virus were reported between 1936 and 1958 in Argentina, but the validity of these findings has been seriously questioned. Nevertheless, serological evidence exists for human infections with a member of the VEE virus complex. Serological surveys conducted in the 1960s indicate a high prevalence of infection of humans and domestic animals with St. Louis encephalitis (SLE), and 2 SLE virus strains have been isolated from rodents. Human disease, however, has rarely been associated with SLE infection. Only 7 isolations of other arboviruses have been described (3 of Maguari, 1 of Aura, 2 of Una, and 1 of an untyped Bunyamwera group virus). In 1977, we began longitudinal field studies in Santa Fe Province, the epicenter of previous equine epizootics, and in 1980 we extended these studies to Chaco and Corrientes provinces. The study sites are described in this paper.
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Christensen, H. A., & Herrer, A. (1973). Attractiveness of sentinel animals to vectors of leishmaniasis in Panama. Am J Trop Med Hyg, 22(5), 578–584.
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Bast, T. F., Whitney, E., & Benach, J. L. (1973). Considerations on the ecology of several arboviruses in eastern Long Island. Am J Trop Med Hyg, 22(1), 109–115.
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