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At least 19 recordsLinked to original sources
PubMed2001

Population mixing and the adaptive divergence of quantitative traits in discrete populations: a theoretical framework for empirical tests.

Empirical tests for the importance of population mixing in constraining adaptive divergence have not been well grounded in theory for quantitative traits in spatially discrete populations. We develop quantitative-genetic models to examine the equilibrium difference between two populations that are experiencing different selective regimes and exchanging individuals. These models demonstrate that adaptive divergence is negatively correlated with the rate of population mixing (m, most strongly so when m is low), positively correlated with the difference in phenotypic optima between populations, and positively correlated with the amount of additive genetic variance (G, most strongly so when G is low). The approach to equilibrium is quite rapid (fewer than 50 generations for two populations to evolve 90% of the distance to equilibrium) when either heritability or mixing are not too low (h2 > 0.2 or m > 0.05). The theory can be used to aid empirical tests that: (1) compare observed divergence to that predicted using estimates of population mixing, additive genetic variance/covariance, and selection; (2) test for a negative correlation between population mixing and adaptive divergence across multiple independent population pairs; and (3) experimentally manipulate the rate of mixing. Application of the first two of these approaches to data from two well-studied natural systems suggests that population mixing has constrained adaptive divergence for color patterns in Lake Erie water snakes (Nerodia sipedon), but not for trophic traits in sympatric pairs of benthic and limnetic stickleback (Gasterosteus aculeatus). The theoretical framework we outline should provide an improved basis for future empirical tests of the role of population mixing in adaptive divergence.

Adaptation, Physiological↗
PubMed1977

An empirical test of the sociocybernetic model.

A theoretical"sociocybernetic" systems analysis model was tested empirically. Two independent groups completed a questionnaire that described their reactions to four hypothetical interpersonal situations. Half of the persons in each group described their reactions to a friend and used Likert scales to rate the unfavorable/favorableness of their (a) verbal responses and subsequent (b) emotional states. Additionally, they completed similar scale ratings that indicated the expected verbal responses and emotional states of their friend. Persons in the other half of each group completed the same interpersonal simulation exercise except that they were asked to describe an interaction with someone other than a friend. The data elements simulated by the computer were the verbal and emotional response ratings. In this simulation, one perons's output becomes the other person's input and vice versa. Strife scores were defined operationally in terms of the unfavorable (negative) conditions generated in the mathematical simulations. In both groups the mean strife scores for friends were significantly lower than mean strife scores for the other two-person interactions.

Computers↗
PubMed1980

Probabilistic income-maximizing behavior in regional migration: an empirical test.

"This paper provides an empirical test of the hypothesis that migrants consider income risk in their evaluation of the returns to migration in that higher levels of income risk for a given region reduce the rate of net migration into that region." Theoretical approaches to the incorporation of income risk in migration models are first considered, and alternative approaches are then tested using data on white and nonwhite net migration in the United States between 1960 and 1970. The results indicate support for the hypothesis that the extent of net migration is inversely affected by income risk.

Americas↗
PubMed2003

Job satisfaction of hospital nurses: an empirical test of a causal model in Taiwan.

AIM: The purpose of this research was to empirically test a model of job satisfaction in Taiwan. METHODS: The model represents a revision of the Price-Mueller model, which is based on empirical research conducted since 1972 at the University of Iowa. This empirical test contributes to the generalization, on cross-national settings, of results from American-based research on job satisfaction. FINDINGS: The results, based on a sample of 308 non-supervisory hospital nurses in Taiwan, indicate that 45% of the variance in job satisfaction was accounted for by the revised model. The work characteristic variable "routinization" had the greatest impact on job satisfaction, followed by the personality traits "positive affectivity" and "job involvement". Although it is difficult to change the routine nature of nursing, the manager should make efforts to diversify the job description and empower his/her subordinates. CONCLUSIONS: It is suggested that having information on a nurse's personality will help to predict her/his future job satisfaction and may lead to improved selection of personnel. In addition, different management styles or reward systems that are sensitive to different personalities should be carefully studied and implemented, as appropriate.

Humans↗
PubMed1987

Migration and mental health: an empirical test of depression risk factors among immigrant Mexican women.

Empirical research in the field of migration and mental health is rare and its recent appearance follows decades of inconsistent reports in the research literature about the risks posed by numerous precipitating and predisposing factors. This article has 2 goals: 1) to summarize critically selected issues and methodological problems regarding mental health implications of migration-adaptation, and, 2) to test empirically hypotheses derived from the Fabrega Migration Adaptation Model to determine whether they have predictive value for depressive symptomatology in a cross-sectional sample of Mexican immigrant women in San Diego county. Findings from bivariate analyses indicate most of the model's factors were significantly related to depressive symptoms. Multivariate analyses identified 1) demographic factors (education-income), 2) perceived economic opportunity, 3) perceived distance between the 2 centers involved in the migration, and 4) loss of interpersonal ties in Mexico as the most parsimonious subset of depression indicators within the model. Implications are discussed.

Acculturation↗
PubMed1989

Strategic regulatory entry deterrence: an empirical test in the ophthalmic market.

This paper provides an empirical test of the theory of strategic regulatory entry deterrence--the theory that subgroups of firms within an industry will use the regulatory process to increase rivals' costs and thereby deter rivals' entry. The results suggest that the commercial practice restrictions present in the ophthalmic industry deterred chain optical firms' entry into the market. This result in combination with earlier findings that the restrictions increase optometrists' prices suggests that cost-raising strategies can be used to disadvantage rivals or drive them out of the market without the need to lower price.

Commerce↗
PubMed1989

Empirical tests demonstrating two coexisting sources of tinnitus: a case study.

Empirical tests for a relation between tinnitus and spontaneous otoacoustic emissions (SOAEs) have been previously presented (Penner & Burns, 1987). Modification of these tests, however, is necessary for the special case reported here in which a female subject has tinnitus consisting of an annoying SOAE in the right ear and tinnitus unrelated to SOAEs in the left ear. This case is of interest because it provides a forum for extending the tests of Penner and Burns (1987) and because the extended tests can be used to prove that one subject's tinnitus can have two distinct sources.

Adult↗
PubMed1998

Validity of regression-based norms: an empirical test of the comprehensive norms with older adults.

This study empirically tested Fastenau and Adams' (1996) concerns about using regression-based norms (RBN) to statistically correct for demographic influences. A widely used RBN system (Heaton, Grant, & Matthews, 1991) was applied to scores from 63 healthy older adults for the Trail Making Test, Boston Naming Test, and Wisconsin Card Sorting Test (WCST). Age influences on all tests were virtually eliminated by the RBNs, whereas education influences were created by the RBN (better educated older adults penalized by the norms). Using RBNs from the Revised WCST Manual also created distortions, far overcorrecting for age. These findings cast considerable suspicion on norms that are generated by statistical regression when there are not adequate numbers of people supporting each demographic cell. Clinically, these norms can lead to higher rates of false negatives (or missed diagnoses) in older adults, especially those with less education and especially women in their 60s.

Adult↗
PubMed2006

An empirical test of the behaviour analysis interview.

The present experiment is the first empirical test of the Behaviour Analysis Interview (BAI), an interview technique developed by F. E. Inbau, J. E. Reid, J. P. Buckley, & B. C. Jayne (2001) designed to evoke different verbal and non-verbal responses from liars and truth-tellers. Inbau et al. expect liars to be less helpful than truth-tellers in investigations and to exhibit more nervous behaviours. Just the opposite predictions, however, follow from the deception literature, which notes that liars take their credibility less for granted and are therefore more aware of their responses and their impact on others. This suggests that liars' answers should be more helpful than truth-tellers' answers, and liars' non-verbal responses should appear more relaxed than truth-tellers' non-verbal responses. In the present experiment, 40 participants (undergraduate students) lied or told the truth about an event during a BAI interview. The interviews were coded according to Inbau et al.'s guidelines. The results showed that, compared to liars, truth-tellers (a) were more naive and evasive when explaining the purpose of the interview, and (b) were less likely to name someone who they felt certain did not commit the crime. Truth-tellers also exhibited more nervous behaviours. The results were consistent with the predictions of the deception literature, and directly opposed to the predictions of BAI.

Adolescent↗
PubMed1989

Left and right-handed dyslexic boys: an empirical test of some assumptions of the Geschwind-Behan hypothesis.

Twenty-six dyslexic boys (13 left-handers and 13 right-handers) were tested for hemispheric asymmetry with dichotic listening (DL) and a visual half-field test (VHF). The purpose of the study was an empirical test of the Geschwind-Behan [Proc. natn. Acad. Sci. USA 79, 5097-5100, 1982] hypothesis of a difference in hemispheric asymmetry between left- and right-handed dyslexic boys. Following Geschwind and Behan, left-handedness and dyslexia are caused by a common factor affecting the development of the left hemisphere in utero which results in a right hemisphere dominance. As a consequence, handedness but not language is shifted to the right hemisphere. We therefore predicted that left-handed dyslexics should be superior to right-handed dyslexics on visuospatial tasks, but perform similar to right-handers on verbal tasks. The results revealed a significant right ear advantage (REA) in both groups during a dichotic listening test to verbal stimuli. The left-handed group was however superior to the right-handed group in recognition of visuo-spatial stimuli presented in the left half-field in a visual half-field test. It is concluded that the results provide some, although weak, support for the Geschwind-Behan hypothesis.

Adolescent↗
PubMed1998

Empirical testing of a longitudinal model derived from the Roy adaptation model.

This article presents the steps and results of the empirical testing of a theoretical longitudinal model, derived from Roy's nursing conceptual model, of the psychosocial determinants of adaptation in different target groups. The model was elaborated and empirically verified based on the integrated results of four longitudinal studies involving groups vulnerable to mental health problems. By means of structural equation analyses, the cross-sectional model was verified at two points in time. The results showed that the model was relatively stable over time. The model was also tested using longitudinal data. Results showed little consistency in the patterns of relationships across studies. The significant links that emerged from the analyses shed some light on the complexity of the process of adaptation to different types of stressors. They underscore the importance for nursing practice to develop interventions aimed at certain variables: perceived stress, conflicts in the exchange of support, and passive and avoidance coping strategies. The results also highlight the importance of the relationship between perceived stress, passive/avoidance coping strategies and psychological distress.

Adaptation, Psychological↗
PubMedDate not supplied

ROC curves and the areas under them for dichotomized tests: empirical findings for logistically and normally distributed diagnostic test results.

Many measures, including sensitivity and specificity, predictive values, and likelihood ratios, are available for the assessment of diagnostic tests. A drawback of the use of these measures is that continuous test results are often dichotomized, with consequent loss of information. Receiver operating characteristic (ROC) curves do not depend on discrimination thresholds, and therefore the area under the ROC curve (AUC) is one of the preferred measures. Although quantitative test results are often presented dichotomized, it would be convenient still to be able to estimate the ROC curve and the AUC. The authors present equations for such estimates when only one pair of a true- and a false-positive rate is given, for inherently logistically and normally distributed data. Illustrative empirical data are provided for both distributions. In contradiction to earlier reports, the authors also show that differential disease verification may skew the ROC curve. The ROC curve is thus not invariant to selection bias.

Bayes Theorem↗
PubMedDate not supplied

The compression of morbidity debate in aging: an empirical test using the gerontological and geriatric population studies in Göteborg, Sweden (H70).

The H70 longitudinal study of aging, Göteborg, Sweden is used to empirically test the compression of morbidity theory advanced by. We reconceptualize compression as postponement of morbidity in the sense of decreasing amounts of illness for increasingly long life spans. Operationally, morbidity is defined as the average number of hospital days in the last year of life. The date of death and the date of 1-year prior to death define the risk period. The linear regression model with age at death, age at death squared, year of birth, and sex are statistically significant with the oldest having the fewest hospital days. The findings offer partial support for the compression of morbidity theory.

Aged↗
PubMed1994

Empirical tests of an information-motivation-behavioral skills model of AIDS-preventive behavior with gay men and heterosexual university students.

This article contains empirical tests of the information-motivation-behavioral skills (IMB) model of AIDS-preventive behavior (J.D. Fisher & Fisher, 1992; W.A. Fisher & Fisher, 1993a), which has been designed to understand and predict the practice of AIDS-preventive acts. The IMB model holds that AIDS-preventive behavior is a function of individuals' information about AIDS prevention, motivation to engage in AIDS prevention, and behavioral skills for performing the specific acts involved in prevention. The model further assumes that AIDS-prevention information and motivation generally work through AIDS-prevention behavioral skills to influence the initiation and maintenance of AIDS-preventive behavior. Supportive tests of the model, using structural equation modeling techniques, are reported with populations of gay male affinity group members (n = 91) and heterosexual university students (n = 174).

Acquired Immunodeficiency Syndrome↗
PubMed1976

Compensatory aspects of dreams: an empirical test of Jung's theory.

Jung's hypothesis that dreams have a compensatory function is clearly stated and well-known, yet has not been empirically tested. Three dream reports for each of 62 students were rated on 15 personality dimensions and compared with scores on the same dimensions as measured by the Edwards Personality Preference Schedule and the Adjective Check List (ACL). Six EPPS scales and 10 ACL scales correlated significantly with their appropriate dream rating scales. However, all significant correlations were positive, a finding that does not supoort Jung but is more in line with the theories of Adler, Fromm, and Hall, who regarded dream content as not substantially different from conscious functioning.

Adolescent↗
PubMed1986

An empirical test of Maslow's theory of need hierarchy using hologeistic comparison by statistical sampling.

Maslow's hierarchy of basic human needs provides a major theoretical framework in nursing science. The purpose of this study was to empirically test Maslow's need theory, specifically at the levels of physiological and security needs, using a hologeistic comparative method. Thirty cultures taken from the 60 cultural units in the Health Relations Area Files (HRAF) Probability Sample were found to have data available for examining hypotheses about thermoregulatory (physiological) and protective (security) behaviors practiced prior to sleep onset. The findings demonstrate there is initial worldwide empirical evidence to support Maslow's need hierarchy.

Behavior↗
PubMed1997

An empirical test of the identity capital model.

In a previous issue of this journal, the identity capital model was presented as part of an effort to better understand the relationship between social context and identity formation (Côté, 1996a). The present paper provides an empirical test of that model as it applies to the late-adolescent passage of university students toward adulthood. A series of research questions are explored which reveal the following: (1) concepts used in the model can be reliably measured; (2) significant relationships exist among certain measures of identity capital resources; (3) these resources have significant associations with measures of identity capital acquisition; (4) over 2 years of university, identity capital increases overall for female students (on a measure of adult identity resolution) and for those of lower social class background (on a measure of community identity resolution); and (5) certain resources acquired before attending university are predictors of identity capital acquisition after 2 years of attendance, net of the identity capital with which students begin university.

Achievement↗