Riverside County Research Articles

First Report of Powdery Mildew on Nandina domestica (Berberidaceae) in North America.

Nandina domestica Thunb. (heavenly bamboo) is an ornamental plant that is widely planted in landscapes in California and other states. Since 1996, powdery mildew disease has been seen on outdoor landscape N. domestica in various regions of California (Alameda, Monterey, Riverside, and Santa Barbara counties). Symptoms consist of reddening of leaf and stem tissues colonized by the fungus and curling and twisting of infected leaves. The following observations were the same for all collected isolates. White ectophytic mycelium was observed on leaves and petioles. Mycelium on leaves was amphigenous, mostly epiphyllous, and effused or in patches. Hyphal appressoria were nipple-shaped to lobed and sometimes opposite in orientation. Conidiophores were cylindrical, straight, sometimes slightly flexuous, 22 to 32 × 6 to 8 μm in dimension, and followed by one to two shorter cells. Conidia were cylindrical, produced singly, and 27 to 42 × 11.5 to 14 μm in dimension. Fibrosin bodies were not observed. Conidial germ tubes were approximately twice the length of the spore, originated from the ends of the spore, and terminated in simple appressoria. Cleistothecia were not present. Based on these characteristics, the fungus was identified as Microsphaera berberidis (DC) Lév. (1). Pathogenicity was confirmed by gently pressing diseased leaves on leaves of healthy N. domestica plants. Plants were incubated in a humidity chamber at 22 to 24°C, and after 10 to 14 days, powdery mildew colonies developed. A voucher specimen was deposited in the University of California Herbarium (UC 1738622). Additional inoculation experiments showed that four other N. domestica cultivars were susceptible (Compacta Nana, Gulf Stream, Harbour Dwarf, and Royal Princess). Helfer (2) noted several possible candidates for the Nandina powdery mildew pathogen in the United Kingdom. However, due to the conidial characteristics of that fungus and the paucity of character descriptions for the several species mentioned, no species name was given to the Edinburgh isolate. In contrast, the mitosporic characteristics of our isolates fit the description for M. berberidis. This is the first report of powdery mildew on N. domestica in North America.

Sage Scrub Revolution? Property Rights, Political Fragmentation, and Conservation Planning in Southern California under the Federal Endangered Species Act

In the U.S., conservation planning under the federal Endangered Species Act (ESA) has increasingly applied to species and habitats located on private property in urbanizing regions. Under the ESAs Section 10(a), habitat conservation plans (HCPs) provide mechanisms for local governments, private landowners, and other stakeholders to proceed with development plans while at the same time undertaking conservation measures for federally listed species. Using a “reconstructed urban regime theory” approach to local policymaking, this paper examines the development of a subregional HCP for the protection of the federally listed Stephens’ Kangaroo Rat (SKR) in western Riverside County, Southern California. Empirically, we demonstrate problems of incorporating property externalities into a subregional planning process and the various ways in which landowners and local progrowth interests have mobilized in response to HCPs developed within the federal ESA framework. Theoretically, we emphasize uneven development within Southern California's suburban-oriented mode of social regulation, which also provides a structural context for evaluating recent moves toward multispecies and ecosystem planning under the State of California’s Natural Communities Conservation Planning (NCCP) framework. A pilot NCCP program for the coastal sage scrub ecosystem is fragmenting into a loosely coordinated amalgam of subregional HCPs developed under diverse local policy regimes. The paper critically discusses the extent to which ecosystem planning in Southern California represents a revolution in the role of the U.S. government in managing conflicts arising from conservation measures on private property in urbanizing regions.

Characteristics of Prisoners in the California Department of Corrections: Race, Ethnicity, and Other Aspects

A study of data from the California Department of Corrections -- the system in California for adult prisoners - shows that there are more Hispanic prisoners than any other group, with African-Americans second in percentage incarcerated. Other data, from the population of 160,846 prisoners, reveals interesting findings. Prisoners seem more likely to come from southern California than from northern California. Drawing on the author's own prison work in California, it is suggested that gang membership may account, in part at least, for the large percentage of prisoners being Hispanic or African-American. Other issues are discussed. Key Words: California, criminal justice system, prisons, drugs, gangs, Hispanics, African-Americans, Crime is a serious social problem in the United States and as in many other countries (Bartol, 1999; Correctional Service of Canada, 1990; Douglas, Burgess, Burgess, & Ressler, 1992; Hodgins, 1993). California is the most highly populated state in the United States. It has been a state where numerous innovative programs have appeared for dealing with crime and with prisoners. It also has a wide array of racial and ethnic groups. So, it is of some value to look at characteristics of prisoners in the state's Department of Corrections, which is the agency that handles adult prisoners. In a previous study, the author reported on the characteristics of prisoners in a California Youth Authority prison treatment program (Eisenman, 1993). Having worked for close to two years in a California Youth Authority intensive treatment program, he was able to draw upon objective data and staff ratings when engaging in this study (Eisenman, 1993). His previous study of official data in California revealed interesting information about crime rates and arrest rates (Eisenman, 1994). Adulthood in California is defined as being 18 years of age or older. Younger prisoners go to a variety of prisons and county-run camps. The worst youth offenders are sent to the California Youth Authority. However, from age 18-25 years of age, a convicted person can be sent either to the California Youth Authority or to the Department of Corrections. Immature, weak offenders, in the 18-25 years age range, are more likely to be sent to the California Youth Authority, while your more normal criminal in this age range is more likely to be sent to an adult prison. Both the California Youth Authority and the California Department of Corrections have mostly prisoners with serious, felony convictions, and often with long histories of committing crimes. Findings The data ppresented here were obtained from the California Department of Corrections. At the time the data were gathered, in the middle of the year 2000, the inmate population comprised 160,846 prisoners, of which the greatest percentage were Hispanics, representing 34.0% of prisoners in the California Department of Corrections. Next come African-Americans, who comprised 31.4% of the prison population, Whites constituted 29.4% of the prison population, while 5.2% were classified as Other. Why would Hispanics be such a high percentage of the prison population? A partial answer comes from the top five counties in terms of inmates in the Department of Corrections. Los Angeles County, which has a high percentage of Hispanics, leads with 34.3% of the prisoners being from Los Angeles County. Then, the percentages drop off greatly from the 34.3% of Los Angeles County. But, the other four counties are all in southern California, where Hispanics would be more likely to be found, than in the northern California counties. The second most populous county is San Diego County, with 8.2% of the prison population being from there; the third most is San Bernardino County, 6.2%; the fourth most is Orange County (right next to Los Angeles County, but with a much wealthier population) 5.3%; and fifth is Riverside County, 5.4%. Although the United States has had a War on Drugs that has led to large numbers of federal prisoners being incarcerated for drug offenses, this is surprisingly not the top cause of incarceration in California, although it is the second largest category of incarceration. …

Investigation of denitrification rates in an ammonia-dominated constructed wastewater-treatment wetland

Abstract Denitrification measurements were made under simulated field conditions using sediment cores and water collected from the Hemet/San Jacinto Multipurpose Demonstration Wetland (Riverside County, California, USA). The 9.9 ha constructed wetland is used to both polish ammonia-dominated secondary municipal effluent and provide migratory bird habitat. The wetland was originally constructed as a marsh-pond-marsh system in 1994. Over the period from January through March 1998, measured denitrification rates averaged 20.9 ± 20.9 μmol N m−2 h−1 within the emergent marsh portions of the wetland and 646 ± 353 μmol N m−2 h−1 in open water areas. The mean areal denitrification removal rate for this period was 0.70 kg N ha−1 d−1, which accounted for about 8% of the total N removed by the wetland. Internal retention was the main N-removal mechanism. Synoptic water quality surveys indicated that denitrification was limited by a lack of nitrification within the wetland. Between April 1998 and January 1999, the we...

Does Nest Placement Affect the Fate or Productivity of California Gnatcatcher Nests?

I monitored 384 California Gnatcatcher (Polioptila californica) nests at five study areas in western Riverside County, California, from 1992 through 1995. Overall, 78.9% of the nesting attempts failed (52.9% from nest predation), and 21.1% fledged young. Vegetation measurements were taken at 207 of 384 nest locations and at 207 randomly selected locations within gnatcatcher territories. Nest placement was not random in that gnatcatchers placed their nests in locations with greater cover and height of perennial vegetation, increased horizontal structural homogeneity, and increased vertical structural homogeneity relative to random locations. The volume of gnatcatcher nest shrubs was lower than that of random shrubs, and concealment was higher at nests than at random shrubs. Nevertheless, variables that differed significantly between nests and random locations were not significantly associated with nesting success, nest predation, nest abandonment, or productivity. The use of specific perennial shrub species as nest substrates was not proportional to the availabilities of the shrub species within the study areas, yet I found no relationship between nesting success and the species of nest shrub. Nesting success appeared to be unrelated to the abundance of perennial shrubs at four of five study areas. My results suggest that factors affecting the fate of California Gnatcatcher nests operate at scales larger than the nest site or nest patch.

Off-Flavor Problems in Two Reservoirs, Associated with Planktonic Pseudanabaena Species

In the summer of 1996, off-flavor episodes involving 2-methylisoborneol (MIB) occurred in two southern California reservoirs: San Vicente Reservoir, in the San Diego area, and Lake Skinner, in western Riverside County. These events resulted in many consumer complaints from the respective communities served. During the San Diego episode, moderate numbers of Pseudanabaena and other plankton were present in the water, and MIB was detected in one sample at 23 ng/l. Two strains of Pseudanabaena that produced MIB were isolated; cultures of this organism yielded 22 and 23 μg/l, respectively. Lake Skinner water also contained a moderate number of Pseudanabaena and other plankton when MIB levels began to rise, with MIB reaching 10 ng/l. Liquid and agar cultures derived from Lake Skinner water developed a strong MIB odor, and eventually three MIB-producing isolates were obtained. MIB levels in the cultures were all less than 1 μg/l. This was the first known MIB episode of planktonic origin in Lake Skinner, and it was the first off-flavor event in either reservoir in which Pseudanabaena was implicated. These two events underscore the potential importance of an organism not generally recognized as a cause of off-flavor in water supplies.

Description of Diedra, New Genus (Lepidoptera: Tortricidae: Tortricinae: Archipini), and Three New Species, Based on Phylogenetic Analysis

Diedra, new genus, is proposed for Argyrotaenia cockerellana (Kearfott), A. wielgusi (Clarke), and 3 new species: D. calocedrana (type locality: Blodgett Forest, 13 miles east of Georgetown, El Dorado County, CA), D. intermontana (type locality: Icthyosaur State Park, Nye County, NV), and D. leuschneri (type locality: Pinyon Crest, Riverside County, CA). A phylogenetic analysis compares the Diedra group to 3 species of Argyrotaenia that are morphologically similar to Diedra using 25 morphological and ecological characters. Cladistic analyses indicate strong support for the distinctiveness of Diedra but weak resolution within Diedra. Nor was there convincing evidence for a sister taxon among A. paiuteana Powell, A. niscana (Kearfott), and A. citrana (Fernald). Ordering of 2 characters and weighting of 2 others increased resolution to a most parsimonious solution.

First Report of Entyloma Polysporum on Sunflower (Helianthus annuus) in Southern California.

During a period of wet weather from December 1996 to March 1997, commercial plantings of sunflower in San Diego County, CA, were infected by a leaf smut, Entyloma polysporum (Peck) Farl. The fungus was observed on sunflowers grown in a greenhouse in San Diego County and also on sunflowers from nurseries in Ventura and Riverside counties. Although the disease was first noticed in 1996, the infection was not of economic significance so no attempt was made to identify the causal agent. However, with continuous cropping of sunflowers year round significant losses were observed on seedlings that were systemically infected as they emerged. This is the first report of E. polysporum causing economic losses on sunflowers. The distinguishing characteristics of this fungus are masses of globose to subglobose spores, pale green to yellow green in color, approximately 12 μm in diameter, with a double wall consisting of an inner pale green wall and outer hyaline sheath. The spores occur in dense masses called sori that completely replace the leaf cells. Young spores are difficult to distinguish from leaf cells in a cursory examination. Older sori form discolored lesions in the leaf ranging from circular to irregular in shape and replace most of the chlorenchyma tissue in the infected lesions. Identification of species of smut fungi such as Entyloma is based on the location of the sori in the vegetative parts of the host, the identification of the host, and the spore morphology (4). Savile (3) reviewed the genus on North American composites and, based on morphological characteristics, concluded that almost all the pathogens were either E. compositarum or E. polysporum, with a few intermediate forms. E. polysporum is characterized by globose spores 10 to 17 μm in diameter, surrounded by cell walls 1 μm thick encased in a 1.5- to 2.5-μm thick smooth hyaline sheath (1). Spores of E. compositarum are smaller, 9 to 12 μm in diameter, thin walled (1 to 1.5 μm), smooth, and without a sheath (2). Vánky (4) lists 33 different species on composites according to their host. He believes E. polysporum only occurs on Ambrosia spp., and does not include E. compositarum in his list of Entyloma spp. Neither author mentions Entyloma infecting any species of Helianthus. Savile concluded that E. calendulae (Oudem.) de Bary, described in Europe, is very similar morphologically to E. polysporum, and is probably the same species. E. polysporum was first described in 1881 by Peck as Protomyces polysporus infecting Ambrosia trifida in New York State. In 1996, it was described on Ambrosia artemesifolia in Hungary (3). In the United States it has been reported on sunflowers in Montana (1,2).

Using a dispersion model to estimate emission rates of particulate matter from paved roads

From January 1996 to June 1997, we carried out a series of measurements to estimate emissions of PM 10 from paved roads in Riverside County, California. The program involved the measurement of upwind and downwind vertical profiles of PM 10, in addition to meteorological variables such as wind speed and vertical turbulent intensity. This information was analyzed using a new dispersion model that incorporates current understanding of micrometeorology and dispersion. The emission rate was inferred by fitting model predictions to measurements. The inferred emission factors ranged from 0.2 g VKT -1 for freeways to about 3 g VKT -1 for city roads. The uncertainty in these factors is estimated to be approximately a factor of two since the contributions of paved road PM 10 emissions to ambient concentrations were comparable to the uncertainty in the mean value of the measurement. At this stage, our best estimate of emission factor lies between 0.1 and 10 g VKT -1; there is some indication that it is about 0.1 g VKT -1 for heavily traveled freeways, and is an order of magnitude higher for older city roads. We found that measured silt loadings were poor predictors of emission factors. The measured emission factors imply that paved road emissions may contribute about 30% to the total PM 10 emissions from a high traffic area such as Los Angeles. This suggests that it is necessary to develop methods that are more reliable than the upwind–downwind concentration difference technique.

Off-flavor problems in two reservoirs, associated with planktonic species

In the summer of 1996, off-flavor episodes involving 2-methylisoborneol (MIB) occurred in two southern California reservoirs: San Vicente Reservoir, in the San Diego area, and Lake Skinner, in western Riverside County. These events resulted in many consumer complaints from the respective communities served. During the San Diego episode, moderate numbers of Pseudanabaena and other plankton were present in the water, and MIB was detected in one sample at 23 ng/l. Two strains of Pseudanabaena that produced MIB were isolated; cultures of this organism yielded 22 and 23 μg/l, respectively. Lake Skinner water also contained a moderate number of Pseudanabaena and other plankton when MIB levels began to rise, with MIB reaching 10 ng/l. Liquid and agar cultures derived from Lake Skinner water developed a strong MIB odor, and eventually three MIB-producing isolates were obtained. MIB levels in the cultures were all less than 1 μg/l. This was the first known MIB episode of planktonic origin in Lake Skinner, and it was the first off-flavor event in either reservoir in which Pseudanabaena was implicated. These two events underscore the potential importance of an organism not generally recognized as a cause of off-flavor in water supplies.

Differences between pickup truck and automobile driver-owners

This study compares pickup truck driver-owners and drivers who owned only automobiles with respect to demographic factors, conditions of use, risk-taking driving behavior, prior driving history and attitudes towards motor vehicle laws. A telephone survey conducted in Riverside County, CA determined that 36% of the households had a pickup truck. Pickup truck owners were primarily male, aged 30–39 years, married, reported lower restraint use and more risky driving behaviors, and had more traffic citations. Differences in behaviors and attitudes were largely a function of age and gender. There is a need to design appropriate occupant safety interventions for those most likely to own pickup trucks.

Modeling the impact of body-contact recreation on pathogen concentrations in a source drinking water reservoir

A modeling study was conducted to evaluate the impact of body-contact recreation (e.g., water skiing, jet skiing, swimming) on pathogen concentrations in a source drinking water reservoir under construction in eastern Riverside County in Southern California. A hybridized Monte Carlo-finite segment model was used to predict pathogen concentrations in the reservoir resulting from pathogen inputs associated with shed fecal material and accidental fecal releases (AFRs). Monte Carlo techniques were incorporated into the finite segment model to define characteristics about individual recreators which affect pathogen loading to the reservoir (e.g., infection, pathogen shedding rate, location). Results of simulations are provided in the form of cumulative distribution and probability density functions derived from uncertainty analyses. The model predicted considerable spatial and temporal variability in pathogen concentrations within the reservoir, with elevated levels of Cryptosporidium, rotavirus, and poliovirus in the epilimnion during periods of high recreational use. Predicted Giardia concentrations were lower than the other pathogens. Hypolimnetic concentrations of all pathogens were generally 1–3 orders of magnitude lower than the overlying epilimnetic concentrations. Model results also suggest that field sampling will underestimate the mean, range and variance of pathogen concentrations in the reservoir. The model was further modified to include a particle tracking scheme to allow for transport of aggregated fecal material. Results from simulations using this approach demonstrate a potential for high pathogen loads due to body-contact recreation periodically reaching treatment plants.

First Report of Three Phaeoacremonium spp. Causing Young Grapevine Decline in California.

A grapevine decline of unknown etiology is currently under investigation in California. Two- to 5-year-old vines show low vigor with undersized trunks, short internodes, uneven wood maturity, sparse foliage, and stunted, chlorotic leaves with interveinal chlorosis and necrosis. Trunks viewed in cross section show dark streaking in few to most of the vascular elements. Pith is compacted and discolored; the surrounding wood is dry with a silvery sheen. Primary roots also show dark streaking in the vascular elements and total root biomass is reduced. Phaeoacremonium spp. were consistently isolated from the roots, crowns, and lower portions of the rootstocks of declining vines but not from adjacent healthy vines. Phaeoacremonium spp. grew slowly out of infected tissues, but sporulated abundantly in culture. Identification was verified from a published key (1). Phaeoacremonium chlamydosporum and P. inflatipes were isolated throughout the northern and central California production areas, but P. aleophilum was isolated only in Riverside County. Koch's postulates were completed for Phaeoacremonium spp. by dipping roots of 2-month-old Carignane grape seedlings (n = 80) in a 108 spores per ml suspension for 30 min. Plants were potted in an artificial soil mix and held in a growth chamber at 25°C. Over 50% of plants inoculated with Phaeo-acremonium spp. developed root, stem, and vascular symptoms within 8 weeks. Each of the individual pathogen species was reisolated from over 75% of the inoculated plants but never from the controls. Similarly, all three Phaeoacremonium spp. are associated with wilt and decline diseases in grapevines in Africa (1) and Europe (2) but this is the first report in North America. While several names for this disease have been used previously with older grapevines, including Esca, apoplexy, and black measles (3), we propose using Phaeoacremonium grapevine decline to describe the diseases caused by P. aleophilum, P. chlamydosporum, and P. inflatipes on young vines.

Mixed-Integer Programming Approach for Designing Land Application Systems at a Regional Scale

Sewage sludge disposal has become more difficult for wastewater-treatment plants because landfill operators are increasingly raising tipping fees and limiting the sludge they will accept. For this reason many municipalities are turning to land application as a means of beneficially disposing of sludges. We have developed a procedure for systemwide planning of biosolids (sewage sludge) land application systems. The system includes multiple treatment plants, agricultural regions, and crops. Our approach considers costs of the following: (1) Biosolids storage; (2) digestion; (3) composting; (4) transportation; and (5) land application over an extended planning horizon. We describe a mixed-integer programming (MIP) algorithm that can be used to simultaneously schedule capacity expansions and route transportation. The objective function minimizes long-term and short-term costs. We use an inventory-type approach to model nitrogen accumulation in the soil over time. Accumulated nitrogen limits the quantity of biosolids that can be applied to a given parcel of land. The model restricts certain crops to composted biosolids according to current Environmental Protection Agency (EPA) regulations. Sewage-treatment plants may opt to either compost their biosolids or upgrade their digestion system to meet U.S. federal standards for land application, and the model settles on an optimal pathogen treatment plan based on storage, transportation, and marketing constraints. The model is used to find an economically efficient solution for the sludge disposal needs of Eastern Municipal Water District (EMWD) in Riverside County, Calif. In this District, a combination of direct land application and composting proves optimal.

Liverworts and hornworts of the Santa Rosa Plateau Ecological Reserve, Riverside County, California

Liverworts and hornworts of the Santa Rosa Plateau Ecological Reserve, Riverside County, California

Lizard feeding by Leptoconops (Brachyconops) californiensis (Diptera: Ceratopogonidae) on desert sand dunes.

Adult females of Leptoconops (Brachyconops) californiensis Wirth & Atchley and 1 female of Leptoconops (Holoconops) sp. near knowltoni were collected from 5 species of lizards in desert sand dune habitats in San Bernardino and Riverside counties, California, and northern Sonora, Mexico. Feeding by L. californiensis was observed on the dorsum (usually the heads) of the lizards, with up to 6 L. californiensis on a host at 1 time. The L. sp. near knowltoni appeared to be trying to feed but did not contain blood. Midges fed during calm, warm daylight periods from March through October. Reptile feeding by Ceratopogonidae is reviewed.

Effects of Nest Parasitism by the Brown-Headed Cowbird on Nesting Success of the California Gnatcatcher

California Gnatcatcher (Polioptila californica californica) nests, from 1992-1995 at five sites in western Riverside County, California, were examined to determine the effects of Brown-headed Cowbird (Molothrus ater obscurus) nest parasitism and cowbird trapping on nest fates. Before cowbird trapping, nest parasitism was 31.5% over the entire breeding season and 45.7% during the period when cowbirds were active. Nest parasitism appeared to decrease gnatcatcher nest success by increasing nest abandonment. However, nests were lost to depredation versus parasitism at a 3:1 ratio. Gnatcatcher eggs were significantly correlated with cowbird eggs beginning the week of 5 May in 1992 and 1993, indicating the onset of parasitism pressure within a breeding season. Considering nests initiated after 5 May, nest parasitism was significantly reduced from 45.7% before cowbird trapping to 9.8% after cowbird trapping, and nest success increased significantly from 11.2% before cowbird trapping to 21.7% after cowbird trapping. Considering nest fates regardless of initiation date, there were no significant differences between no-trap and trap periods. Comparisons of no-trap versus trap nest fates before 5 May indicated that nest abandonment increased significantly from 3.3% for the no-trap period to 28.7% during the trapping period. At the same time, nest success decreased significantly from 35.0% during the no-trap period to 15.7% during the trap period. Gains in nest success from decreased nest parasitism were negated by increased nest abandonment before cowbirds were active.

Recent Work at the Lithia Dike Claim, Cahuilla Mountain, Riverside County, California

Recent Work at the Lithia Dike Claim, Cahuilla Mountain, Riverside County, California

Groundwater rise and hydrocollapse: technical and political implications of ‘Special Geologic Report Zones’ in Riverside County, California, USA : R. J. Shlemon, in: Land subsidence. Proc. international symposium, The Hague, 1995, ed F.B.J. Barends & others, (IAHS; Publication, 234), 1995, pp 481–486

Rapid urbanization in the semi-arid southwestern part of Riverside County, California is made possible only by the large-scale importation of water for domestic use. The resulting irrigation run-off and infiltration has caused groundwater levels to rise over 20 m within the past few years, particularly in former, alluvium-filled channels. Soil hydrocollapse, differential settlement and ground fissures are now occurring, causing extensive damage to houses, schools and related infrastructure. Alleged property damages exceed 50 million (US) dollars, and litigation has ensued. For public safety, the County of Riverside established two Special Geologic Report Zones, each about 500 ha, deemed CaliforniaOaks and Silverhawk, respectively. Inretrospect: the formation of the zones has proven to be administratively time- consuming and expensive; the litigation between home-owners, builders, geotechnical firms and reviewing agencies is divisive; home values, even for undamaged structures, have been reduced owing to disclosure laws; and the geotechnical community now recognizes, from sad experience, that rapid urbanization and related water level rise accelerates the potential for soil hydrocollapse and extensive property damage.

The Anatomy of Disappointment: A Naturalistic Test of Appraisal Models of Sadness, Anger, and Hope

Vignette and autobiographical recall studies have often been used to test models of the appraisals associated with specific emotions. Recently, critiques of both methodologies have called into question the applicability of appraisal theory to naturally-occurring emotional responses. This study examined supporter's responses to Ross Perot's withdrawal from the 1992 presidential race to assess the extent to which appraisal models accurately capture responses to a naturally-occurring event. Supporters in Riverside County, California (N = 227) completed questionnaires concerning their interpretations of the event, their initial emotional reactions, changes in their reactions in the weeks immediately following Perot's withdrawal, and their plans. Appraisal models correctly predicted the dimensions of agency and coping potential that served to differentiate sadness from anger, and the appraisals and plans associated with hope. Appraisal models did not predict the strong focus of sad supporters on their past goa...