Showing papers by "Miami University published in 1997"

Meaning in the context of stress and coping

Abstract: Although theoretical and empirical work on topics related to meaning and meaning making proliferate, careful evaluation and integration of this area have not been carried out. Toward this end, this...

Circumstances and consequences of falls in independent community-dwelling older adults

Abstract: BACKGROUND: knowledge of the circumstances and consequences of falls in older adults is important for understanding the aetiology of falls as well as for effective clinical assessment and design of fall prevention strategies. Such data, however, are relatively scarce, especially in community-dwelling elders. METHOD: accidental falls (including their circumstances and consequences) occurring in 96 male and female participants between 60 and 88 years of age were monitored prospectively for 1 year. After the monitoring period, participants were divided into three groups based on fall status: non-fallers (n = 46), one-time fallers (n = 27) and recurrent fallers (n = 23). Frequency distributions were created for selected circumstances and consequences of falls and the prevalence of these consequences were examined. RESULTS: 50 participants (52%) fell during the 1 year period, amassing 91 falls. Trips and slips were the most prevalent causes of falls, accounting for 59% of falls. Falls most often occurred during the afternoon and while subjects walked on level or uneven surfaces. Fallers most commonly attributed falls to hurrying too much. Fractures resulted from five of the 91 falls and eight other falls resulted in soft tissue injuries that required treatment by a physician. There were no differences between one-time and recurrent fallers in the circumstances and consequences of falls. However, several notable differences were found between men (n = 20) and women (n = 30) who fell. Falls by men most often resulted from slips whereas falls by women most often resulted from trips. Moreover, women and men differed in the time of the year in which falls occurred, with men falling most often during winter and women during summer. CONCLUSIONS: the results of this study provide insight into the circumstances and consequences of falls among independent community-dwelling older adults and suggest some possible ways of preventing falls. Preventive services, however, should not solely target recurrent fallers, nor should the type of services necessarily differ for one-time and recurrent fallers. Language: en

Regulation of fatty acid synthesis

Abstract: All plant cells produce fatty acids from acetyl-CoA by a common pathway localized in plastids. Although the biochemistry of this pathway is now well understood, much less is known about how plants control the very different amounts and types of lipids produced in different tissues. Thus, a central challenge for plant lipid research is to provide a molecular understanding of how plants regulate the major differences in lipid metabolism found, for example, in mesophyll, epidermal, or developing seed cells. Acetyl-CoA carboxylase (ACCase) is one control point that regulates rates of fatty acid synthesis. However, the biochemical modulators that act on ACCase and the factors that in turn control these modulators are poorly understood. In addition, little is known about how the expression of genes involved in fatty acid synthesis is controlled. This review evaluates current knowledge of regulation of plant fatty metabolism and attempts to identify the major unanswered questions.

On the Other Hand: Current Issues in and Meta-Analysis of the Behavioral Laterality of Hand Function in Nonhuman Primates

Abstract: The last decade has seen a resurgence of interest in laterality of function in primates, especially in hand use as it links to handedness and language in Homo sapiens. Manual lateralization of behavior in humans reflects asymmetry in cerebral structure, which must have evolved from nonhuman progenitors. To what extent is hand function lateralized in our nearest living relations? First, we address current issues of theory and methodology: statistics, measurement, variables, setting, sensory modality, and sample size. Specific topics include preference vs. performance, posture, bimanuality, inheritance, and arm asymmetry. We categorize the published literature in a descriptive, classificatory framework of five levels that range from Level 1, ambilaterality, to Level 5, human-like handedness. In a meta-analysis we put 241 published data-sets to a methodological test of seven criteria and code the 48 survivors onto the levels framework, by taxonomic grouping (prosimian, New World monkey, Old World monkey, ape, chimpanzee). Primates at Level 1 are mostly wild or naturalistic populations performing spontaneous species-typical behavior patterns. Most primates are at Levels 2 and 3, that is, individually lateralized to either side, especially on complex, demanding or practiced tasks, usually as devised in captive settings. Only chimpanzees show signs of population-level bias (Levels 4 and 5) to the right, but only in captivity and only incompletely. We conclude that nonhu- man primate hand function has not been shown to be lateralized at the species level—it is not the norm for any species, task, or setting, and so offers no easy model for the evolution of human handedness. Yrbk Phys Anthropol 40:201- 232, 1997. r 1997 Wiley-Liss, Inc.

Disclosing New Worlds: Entrepreneurship, Democratic Action, and the Cultivation of Solidarity

Abstract: Both the commonsensical and leading theoretical accounts of entrepreneurship, democracy, and solidarity fail to describe adequately entrepreneurial, democratic, and solidarity‐building practices. T...

Invasibility and effects of Amur honeysuckle in Southwestern Ohio forests.

Abstract: The Asian exotic Amur honeysuckle (Lonicera maackii [Rupr.] Herder) has become the dominant shrub in many forests in southwestern Ohio and in some other locations in the eastern United States. Our research focused on the invasibility of forest communities and relationships of L. maackii to the abundance of tree seedlings and herbs. We surveyed 93 forest stands near Oxford, Ohio (USA) to determine L. maackii cover, time since invasion, tree canopy cover, tree basal area, and a shade tolerance index. Stepwise multiple regression indicated that greater than one-half of the variation (r2 = 0.550) in Lonicera cover was correlated to five variables (in descending order of importance): tree canopy cover, distance from Oxford, shade tolerance index, tree basal area, and time since invasion. The results suggest that high light levels and proximity to an abundant seed source increase forest invasibility. Tree seedling density, species richness of seedlings, and herb cover were all inversely related to L. maackii cover. When Lonicera becomes abundant, future structure and composition of forests could be affected and local populations of herbs threatened.

Nutrient recycling and herbivory as mechanisms in the “top–down” effect of fish on algae in lakes

Abstract: In lakes, top predators (fish) often influence the abundance of primary producers (phytoplankton) through food web interactions: phytoplankton biomass is often greater when planktivorous fish are abundant than when they are rare, and phytoplankton community structure is often affected by fish. Three mechanisms can account for these “top–down” effects of fish: decreased herbivory by zooplankton when fish biomass is high; modification of nutrient recycling rates by the herbivorous zooplankton assemblage as fish biomass varies; and nutrient recycling by fish. These processes were experimentally separated and their relative importance quantified in Tuesday Lake, Michigan. This was accomplished by manipulating the abundance of planktivorous fish or zooplankton in enclosures containing natural phytoplankton communities, and by incubating phytoplankton in nutrient-permeable chambers (which excluded herbivores) placed inside these enclosures. In large enclosures with all trophic levels, several phytoplankton taxa and total phytoplankton biomass showed increased abundance in the presence of fish compared to enclosures without fish. Several taxa also showed significantly greater abundance in nutrient-permeable chambers incubated in enclosures with fish than in chambers incubated in enclosures without fish. The latter result indicates that some phytoplankton taxa respond to fish even when separated from direct herbivory but exposed to nutrients recycled by consumers. Thus, consumer-mediated nutrient recycling had strong effects on phytoplankton community dynamics and could partly explain the “top–down” effects of fish. Most phytoplankton taxa responded to consumer-mediated nutrient recycling, especially dinoflagellates and chrysophytes. In separate enclosures, phytoplankton were exposed to contrasting zooplankton assemblages shaped by fish predation but without fish being present. The response of phytoplankton was not as strong as in the case of fish manipulations. Furthermore, the community-level response of phytoplankton was weaker in nutrient-permeable chambers placed in these enclosures than in chambers incubated in enclosures with fish. Nutrient limitation assays showed that manipulation of fish decreased phosphorus limitation of phytoplankton, while direct manipulation of zooplankton had no effect on phosphorus limitation. These results provide experimental evidence that food web effects on nutrient recycling are important in controlling phytoplankton community dynamics. Results also suggest that some of these effects are expressed via direct recycling of nutrients by fish, as well as by fish-induced effects on nutrient recycling by herbivores. Nutrient-mediated effects of top predators on primary producers should be incorporated into future models of “top–down” control of food web dynamics.

Service loyalty: implications for service providers

Abstract: Service industries have been, and will continue to be, largely responsible for much of the domestic and international economic growth in the USA. Service loyalty, which can be obtained by building relationships and providing excellent customer service, is often the key factor that builds competitive advantage for service providers. The main goal article is to provide a conceptual framework for service loyalty, but one that is not based on empirical support. Contends that this framework can assist service providers in determining the type of loyalty conditions that are likely to exist for specific service industries. Offers in addition some guidelines with which to devise appropriate marketing strategies for each service loyalty condition.

Modeling and Management of Urban Stormwater Runoff Quality: A Review

Abstract: Nonpoint source (NPS) pollution from urban runoff has been established as a major cause of receiving water degradation. In an effort to control this problem, new regulations have been passed in the U.S.A. and federal, state, and local agencies are devising urban runoff management programs. This paper reviews recent regulations and studies related to urban stormwater runoff control and planning in the U.S.A.; discusses fundamentals of urban NPS pollution including transport processes and types and sources of pollutants; reviews current hydrologic and water quality mathematical models used in the U.S.A.; presents case studies in both modeling and management; and describes fundamentals of Best Management Practices (BMPs) in urban runoff control. Finally, it summarizes future research needs.

The scientific attitude inventory: A revision (SAI II)

Abstract: The Scientific Attitude Inventory (SAI) was developed and field tested 25 years ago. It has been used extensively throughout the world, and it continues to be used. Reports of its use and sugges- tions for revision provide impetus for revision. The revision retains the original position statements of at- titudes assessed and the original attitude statements with changes made only to improve readability and to eliminate gender-biased language. Also, in response to critical analysis, the SAI II uses a five-response Likert Scale. The new version is shorter, 40 items instead of 60 in the original. The SAI II was field test- ed with 557 students in Grades 6, 9, and 12. The top and bottom 27% of scorers for the total inventory were compared for the subscales. A statistically significant difference was obtained for each t-test com- parison. Face validity for the SAI II is claimed on the basis of the original judgments of a panel of judges regarding the attitude position statements which have not been altered. A split-half reliability coefficient of .805 was computed for the entire group of 557 respondents. Cronbach's alpha reliability coefficient is .781. J Res Sci Teach 34: 327-336, 1997.

Nitrogen and phosphorus excretion by detritivorous gizzard shad in a reservoir ecosystem

Abstract: The detritivorous fish, gizzard shad (Dorosoma cepedianum), provides nutrients to phytoplankton in reservoirs by ingesting organic detritus associated with sediments and excreting substantial quantities of nutrients such as N and P in soluble forms that are highly available to phytoplankton, We estimated nutrient excretion by gizzard shad in a eutrophic reservoir (Acton Lake, Ohio) during April-October 1994 by measuring N and P excretion of fieldcaught fish (n = 135). Excretion rates were then extrapolated to nutrient release by the gizzard shad population using quadrat rotenone biomass estimates, electrofishing surveys, and historic seasonal trends. N and P excretion were positively correlated with fish wet mass and temperature, but mass-specific excretion declined with increasing fish mass. Lakewidc gizzard shad biomass in July 1994 was 417 kg ha -I, Our estimates of nutrient excretion by the gizzard shad population ranged from 0.487 to 0.769 pmol NH,-N liter-’ d-l and 0.022 to 0.057 pmol soluble reactive phosphorus liter -I d .I, with the highest excretion occurring during mid-summer through early fall. The low N : P ratio at which gizzard shad excrete [mean molar N : P = 16.75 (kO.89 SE)] may alter phytoplankton community composition, favoring cyanobacteria. Our results indicate that nutrient excretion by detritivorous fish can be an important source of nutrients to open waters, especially when other sources of nutrients are reduced.

Postural dynamics and the preferred critical boundary for visually guided reaching.

Abstract: How do people choose an action to satisfy a goal from among the actions that are afforded by the environment? In 3 experiments the action modes used by actors to reach for a block placed at various distances from them were observed. In each experiment, when actors were not restricted in how they could reach for the object, the transition from their reaching using only arm extension to a mode of reaching in which they used the upper torso to lean forward occurred at closer distances than each actor's absolute critical boundary, beyond which the former action was no longer afforded. In Experiments 2 and 3 actors' seated posture was varied so that the effect of postural dynamics on the distance at which actors actually chose to make the transition between action modes, the preferred critical boundary, could be examined. The results are consistent with the proposal that the preferred critical boundary reflects the relative comfort of available modes of reaching.

“top–down” trophic interactions in lakes: effects of fish on nutrient dynamics

Abstract: We conducted enclosure experiments over two summers in Tuesday Lake, Michigan, to assess how a gradient of zooplanktivorous fish biomass affected the dynamics of nutrients (nitrogen, N, and phosphorus, P), and their partitioning among ecosystem compartments. In both years, fish (the cyprinid Phoxinus eos) reduced the abundance of large zooplankton species and increased the biomass of phytoplankton as predicted by the top–down control hypothesis. Fish had strong effects on the dynamics and fluxes of N and P. Total P concentrations in the water column declined over time in all enclosures, but fish slowed the rate of decline. Thus total water column P increased with increasing fish biomass. Total N increased less strongly with increasing fish biomass, and thus the total N:P ratio decreased with increasing fish biomass. The concentrations of particulate carbon, nitrogen, and phosphorus in the water column also increased with increased fish biomass. Particulate N:P ratio decreased with increased fish biomass, but effects were weaker compared to effects on total N:P ratios. Nutrient ratios of the zooplankton fraction (particles >63 μm) showed a response that was transient but consistent with observed trends in zooplankton species composition. In particular, when the large cladocerans Daphnia and Holopedium increased upon exclusion of fish, C:P and N:P ratios of the zooplankton fraction showed distinct declines, corresponding to the relatively high body P contents of these taxa. Phosphorus budgets revealed that fish were a net source of P to the water column, because they lost mass during the experiments, even at densities below those in the lake. However, loss of P from fish could not account for the higher total P concentration observed in enclosures with fish compared to fishless enclosures. The absolute amount of P sinking from the water column increased with increasing fish biomass but decreased when expressed as percentage of total P sinking, again suggesting that the presence of fish increases the relative retention of P the water column. The rate of decline in water column total P in the presence of fish was accurately predicted by sedimentation of P from the water column and other fluxes. Our results support the hypothesis that fish can exert major influences on the dynamics, distribution, and ratios of limiting nutrients.

Relational demography in supervisor- subordinate dyads: Impact on subordinate job satisfaction, burnout, and perceived procedural justice

Abstract: Summary Although research has shown that demographic dissimilarity within groups is negatively associated with organizational attachment-orientated variables, few studies have investigated its relations with other job-related variables. Focusing on relational demographics within the context of superior-subordinate dyads, associations between relational demographic characteristics and subordinate job attitudes and perceptions were examined using polynomial regression. Relational race was found to correlate with perceptions of procedural justice and job satisfaction, but not job burnout. The implications of these findings for future relational demographic research are discussed. ? 1997 by John Wiley & Sons, Ltd. J. Organiz. Behav. 18: 351-362 (1997)

Commitment processes in accounts of the development of premarital relationships

Abstract: CATHERINE A. SURRA The University of Texas at Austin DEBRA K. HUGHES Miami University* We examined the subjective processes by which premarital partners (n = 113) become more or less committed to wed over time. Two commitment processes were identified. In relationshipdriven commitments, commitment evolved smoothly with few reversals. To explain changes in commitment, partners focused on their interaction and activities with one another and with their joint network and on positive beliefs about the relationship and about network members. Eventdriven commitments had more extreme changes in commitment, with sharp downturns alternating with sharp upturns. Partners attributed changes to episodes of self-disclosure and conflict, negative relationship beliefs, separate interaction with network members, and negative network beliefs. On several measures, event-driven partners reported more negative relationship experiences and were less compatible. Yet the two groups did not differ on love or other indicators of involvement. The implications of the two processes for marital decisions are discussed. Key Words: commitment, mate selection, premarital relationships. Whether to wed and whom to wed are among the most consequential decisions that individuals make during their lifetimes. In order to understand fully how individuals make these decisions, two sets of possible influences need to be considered (Surra, Hughes, & Jacquet, in press). The first set is rooted in theories about factors that influence decisions about whom to wed. This set of causes corresponds to an outsider's perspective on mate selection. Research from an outsider's perspective is deductive; investigators make hypotheses about what factors are influential and then test their hypotheses. Most research on mate selection has followed this tradition (see Surra, 1990, for a review). Outsiders' perspectives on mate selection, as evidenced particularly in compatibility theories, generally assume that selecting a mate is approached rationally, with partners taking care to select someone who is a good match (cf. Huston, Surra, Fitzgerald, & Cate, 1981). In this study, we take an insider's perspective, and examine individuals' own explanations for their decisions about marriage. An individual's own reasons for choosing a mate are the subjective causes that influence marital decisions, and they constitute the second set of influences on marital decisions (Surra et al., in press). Subjective causes may or may not resemble those that are influential from an outsider's perspective. The degree to which coupled partners have social networks that overlap, for example, predicts progress toward marriage (cf. Milardo, 1982), but the partners may not be aware of the influence of that social structure. Instead, partners may be more concerned about other features of the network, such as how family members and close friends feel about their dating partner. This study concerns the subjective processes by which premarital partners become more or less committed to wed. What factors do individuals themselves say they weigh when making decisions about marital commitment? Is the decision process as carefully wrought and rooted in tests of homogamy and compatibility as many scholars assume, or is it more capricious and grounded in factors such as love, an auspicious confluence of life events, or personal readiness to wed? More than likely, subjective decisions about marital commitment are based on combinations of different considerations, and the considerations may vary for different people. The goals of this study are to identify the different subjective processes engaged in by different partners. The subjective processes are described in terms of the combinations of causes that individuals say they consider, as well as the nature of their developing commitment (e.g., how unstable it is). DEFINING AND MEASURING MARITAL COMMITMENT In its most general sense, commitment concerns partners' beliefs about whether their relationship is likely to continue over the long run (e. …

Preference for Presidentialism: Postcommunist Regime Change in Russia and the NIS

Abstract: The recent wave of democratic transitions has stimulated scholarly interest in a previously undeveloped area of study: comparative presidentialism. Comparative presidentialism seeks to define variant types of presidentialism that have emerged from transition processes, to identify the conditions that shape institutional choice and to understand more clearly the causal relationship between institutional choice and democratic regime outcomes. Using the postcommunist transitions, this paper contributes to the emerging comparative presidentialism literature by suggesting a revision to the argument that presidentialism leads to failed democratic transitions. The paper focuses attention away from the institutional rules of the game and toward the actors who actually make the institutional choice. Three postcommunist cases, distinguished by their different regime outcomes, are compared: Russia, Uzbekistan, and Estonia.

The Effects of Environmental Attitudes on Apparel Purchasing Behavior

Abstract: Although consumers' environmental concern has increased, little empirical research regarding environmental attitudes and clothing purchasing behavior has been reported. This study builds on the lim...

Reduced Gravitropism in Hypocotyls of Starch-Deficient Mutants of Arabidopsis

Abstract: Gravitropism was examined in dark- and light-grown hypocotyls of wild-type (WT), two reduced starch mutants (ACG 20 and ACG 27), and a starchless mutant (ACG 21) of Arabidopsis. In addition, the starch content of these four strains was studied with light and electron microscopy. Based on time course of curvature and orientation studies, the graviresponse in hypocotyls is proportional to the amount of starch in a genotype. Furthermore, starch mutations seem to primarily affect gravitropism rather than differential growth since both phototropic curvature and growth rates among the four genotypes are approximately equal. Our results suggest that gravity perception may require a greater plastid mass in hypocotyls compared to roots. The kinetics of gravitropic curvature also was compared following reorientation at 45 degrees, 90 degrees, and 135 degrees. As has been reported for other plant species, the optimal angle of reorientation is 135 degrees for WT Arabidopsis and the two reduced starch mutants, but the magnitude of curvature of the starchless mutant appears to be independent of the initial angle of displacement. Taken together, the results of the present study and our previous experiments with roots of the same four genotypes [Kiss et al. (1996) Physiol. Plant. 97: 237] support a plastid-based hypothesis for gravity perception in plants.

Exercise-Induced Oxidative Stress Before and After Vitamin C Supplementation

Abstract: Vitamin C (ascorbic acid) was supplemented (1 g/day) for 1 day and 2 weeks in the same subjects. Plasma thiobarbituric acid reacting substances (TB ARS) and oxygen radical absorbance capacity (ORAC) before and after 30 min submaximal exercise were measured. Different vitamin C supplementations did not affect resting TB ARS or ORAC. Following 30 min exercise, values for TBARS were 12.6 and 33% above rest with 1 day and 2 weeks of vitamin C supplementation, respectively, compared to 46% higher with placebo. ORAC did not significantly change (11%) after exercise with a placebo, nor when subjects were given vitamin C supplements for 1 day or 2 weeks (4.9% and 5.73%, respectively). TBARS:ORAC, a ratio representing oxidative stress, increased 32% (p < .05) with placebo compared to 5.8 and 25.8% with vitamin C supplements for 1 day and 2 weeks, respectively. It was concluded that exercise-induced oxidative stress was highest when subjects did not supplement with vitamin C compared to either 1 day or 2 weeks of v...

Positive Meaningful Events and Coping in the Context of HIV/AIDS

Abstract: Most research on coping with chronic stress tends to focus inquiry on strategies that help the person manage stressor-related demands. In the case of coping with a debilitating illness, for example, the search often focuses on strategies that are related to managing the primary consequences of the illness, including disease-related limited mobility, pain, or dysphoria, and the secondary consequences of the illness, including disrupted family relationships or changes in role functioning. However, the lives of people with a debilitating illness consist of more than just their illness. They may have warm family relationships, friends with whom they talk, or work or other activities that interest them. These other aspects of people’s lives may play an important role in sustaining their well-being while they are coping with their illness. Thus, a full understanding of the coping process in the context of chronic stress may need to take into account aspects of people’s lives that at first blush do not seem to be related directly to how they cope with the chronic stress per se.

Why Don't Chimpanzees in Gabon Crack Nuts?

Abstract: Some populations of wild chimpanzees (Pan troglodytes) use hammers and anvils of stone or wood to crack open nuts for food. Others do not. The aim of this study was to ask why one non-nut-cracking population, in the Lope Reserve, Gabon, lacks this useful form of tool use. We tested 10 hypotheses: (1) nuts are absent; (2) nuts are few; (3) nuts are unsuitable; (4) hammers are absent; (5) hammers are unsuitable; (6) anvils are absent; (7) anvils are unsuitable; (8) nuts are displaced by better food items; (9) intelligence is insufficient; and (10) knowledge is insufficient. All but the last are clearly falsified, leaving by exclusion the likelihood that Lope's chimpanzees lack the technology—knowledge of appropriate technique—to exploit this resource. Thus, the behavioral differences across populations of these apes are cultural and not environmentally dictated. This explanation is congruent with the distribution of chimpanzee nut-cracking across Africa.

A comparative ultrastructural analysis of exine pattern development in wild-type Arabidopsis and a mutant defective in pattern formation

Abstract: In order to identify factors necessary for the establishment of the reticulate pollen wall pattern, we have characterized a T-DNA tagged mutant ofArabidopsis thaliana that is defective in pattern formation. This study reports the results of an ultrastructural comparison of pollen wall formation in the mutant to wall development in wild-type plants. Pollen wall development in the mutant parallels that of wild-type until the early tetrad stage. At this point in wild-type plants, the microspore plasma membrane assumes a regular pattern of ridges and valleys. Initial sporopollenin deposition occurs on the ridges marking the beginning of probacula formation. In contrast, the plasma membrane in the mutant appears irregular with flattened protuberances and rare invaginations. As a result, the wild-type regular pattern of ridges and valleys is not formed. Sporopollenin is randomly deposited on the plasma membrane and aggregates on the locule wall; it is not anchored to the membrane. Our finding that the mutation blocks the normal invagination of the plasma membrane and disrupts the proper deposition of sporopollenin during wall formation suggests that the mutation could be in a gene responsible for pattern formation. These results also provide direct evidence that the plasma membrane plays a critical role in the establishment of the pollen wall pattern.

Exposure-response analysis of risk of respiratory disease associated with occupational exposure to chrysotile asbestos.

Abstract: OBJECTIVES: To evaluate alternative models and estimate risk of mortality from lung cancer and asbestosis after occupational exposure to chrysotile asbestos. METHODS: Data were used from a recent update of a cohort mortality study of workers in a South Carolina textile factory. Alternative exposure-response models were evaluated with Poisson regression. A model designed to evaluate evidence of a threshold response was also fitted. Lifetime risks of lung cancer and asbestosis were estimated with an actuarial approach that accounts for competing causes of death. RESULTS: A highly significant exposure-response relation was found for both lung cancer and asbestosis. The exposure-response relation for lung cancer seemed to be linear on a multiplicative scale, which is consistent with previous analyses of lung cancer and exposure to asbestos. In contrast, the exposure-response relation for asbestosis seemed to be nonlinear on a multiplicative scale in this analysis. There was no significant evidence for a threshold in models of either the lung cancer or asbestosis. The excess lifetime risk for white men exposed for 45 years at the recently revised OSHA standard of 0.1 fibre/ml was predicted to be about 5/1000 for lung cancer, and 2/1000 for asbestosis. CONCLUSIONS: This study confirms the findings from previous investigations of a strong exposure-response relation between exposure to chrysotile asbestos and mortality from lung cancer, and asbestosis. The risk estimates for lung cancer derived from this analysis are higher than those derived from other populations exposed to chrysotile asbestos. Possible reasons for this discrepancy are discussed.