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Individual Traits (individual + trait)
Selected AbstractsAN EXPLORATION OF MEMBER ROLES AS A MULTILEVEL LINKING MECHANISM FOR INDIVIDUAL TRAITS AND TEAM OUTCOMESPERSONNEL PSYCHOLOGY, Issue 2 2005GREG L. STEWART We use data from 220 individuals in 45 teams to examine team member roles as a cross-level linking mechanism between personality traits and team-level outcomes. At the individual level, peer ratings of task role behavior relate positively with Conscientiousness and negatively with Neuroticism and Extraversion. Peer ratings of social role behavior relate positively with Agreeableness and negatively with Openness to Experience. At the team level, a composition process of aggregation operates such that the mean for social roles corresponds with social cohesion. Compilation processes of aggregation also occur, as the variance of social roles corresponds negatively with task performance, and the variance of task roles corresponds negatively with cohesion. Skew of the distribution for social roles within each team,a measure of critical mass of members individually enacting the role,also correlates with social cohesion. [source] Architectural and growth traits differ in effects on performance of clonal plants: an analysis using a field-parameterized simulation modelOIKOS, Issue 5 2007Radka Wildová Individual traits are often assumed to be linked in a straightforward manner to plant performance and processes such as population growth, competition and community dynamics. However, because no trait functions in isolation in an organism, the effect of any one trait is likely to be at least somewhat contingent on other trait values. Thus, to the extent that the suite of trait values differs among species, the magnitude and even direction of correlation between values of any particular trait and performance is likely to differ among species. Working with a group of clonal plant species, we assessed the degree of this contingency and therefore the extent to which the assumption of simple and general linkages between traits and performance is valid. To do this, we parameterized a highly calibrated, spatially explicit, individual-based model of clonal plant population dynamics and then manipulated one trait at a time in the context of realistic values of other traits for each species. The model includes traits describing growth, resource allocation, response to competition, as well as architectural traits that determine spatial spread. The model was parameterized from a short-term (3 month) experiment and then validated with a separate, longer term (two year) experiment for six clonal wetland sedges, Carex lasiocarpa, Carex sterilis, Carex stricta, Cladium mariscoides, Scirpus acutus and Scirpus americanus. These plants all co-occur in fens in southeastern Michigan and represent a spectrum of clonal growth forms from strong clumpers to runners with long rhizomes. Varying growth, allocation and competition traits produced the largest and most uniform responses in population growth among species, while variation in architectural traits produced responses that were smaller and more variable among species. This is likely due to the fact that growth and competition traits directly affect mean ramet size and number of ramets, which are direct components of population biomass. In contrast, architectural and allocation traits determine spatial distribution of biomass; in the long run, this also affects population size, but its net effect is more likely to be mediated by other traits. Such differences in how traits affect plant performance are likely to have implications for interspecific interactions and community structure, as well as on the interpretation and usefulness of single trait optimality models. [source] Genetic and environmental contributions to variation in baboon cranial morphologyAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2010Charles C. Roseman Abstract The development, function, and integration of morphological characteristics are all hypothesized to influence the utility of traits for phylogenetic reconstruction by affecting the way in which morphological characteristics evolve. We use a baboon model to test the hypotheses about phenotypic and quantitative genetic variation of traits in the cranium that bear on a phenotype's propensity to evolve. We test the hypotheses that: 1) individual traits in different functionally and developmentally defined regions of the cranium are differentially environmentally, genetically, and phenotypically variable; 2) genetic covariance with other traits constrains traits in one region of the cranium more than those in others; 3) and regions of the cranium subject to different levels of mechanical strain differ in the magnitude of variation in individual traits. We find that the levels of environmental and genetic variation in individual traits are randomly distributed across regions of the cranium rather than being structured by developmental origin or degree of exposure to strain. Individual traits in the cranial vault tend to be more constrained by covariance with other traits than those in other regions. Traits in regions subject to high degrees of strain during mastication are not any more variable at any level than other traits. If these results are generalizable to other populations, they indicate that there is no reason to suppose that individual traits from any one part of the cranium are intrinsically less useful for reconstructing patterns of evolution than those from any other part. Am J Phys Anthropol 143:1,12, 2010. © 2010 Wiley-Liss, Inc. [source] Mediational role of values in linking personality traits to political orientationASIAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 2 2009Gianvittorio Caprara Two studies use the Five Factor Model of traits and Schwartz's (1992) theory of basic personal values to assess the mediational role of values in linking traits to voting choice and left-right ideology. Both left- and right-wing voters showed distinctive traits and values that were congruent with their ideologies. Structural equation modelling supported a hypothesized full mediation model. Individuals' traits of openness, conscientiousness and agreeableness explained significant variance in the politically relevant values of security and universalism, and these self-reported values, in turn, explained the voters' political orientations. These findings held across age (adolescents and adults) and were corroborated using both cross-sectional and longitudinal data. [source] Biodiversity conservation in Mediterranean and Black Sea lagoons: a trait-oriented approach to benthic invertebrate guildsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2008A. Basset Abstract 1. The extent to which conservation of biodiversity enforces the protection of ecosystem functioning, goods and services is a key issue in conservation ecology. 2. In order to address this conservation issue, this work focused on community organization, linking community structure, as described both in taxonomic and functional terms, to community functioning and ecosystem processes. 3. Body size is an individual functional trait that is deterministically related to components of ecosystem functioning such as population dynamics and energy flow, and which determines components of community structure. Since body size is an individual trait that reflects numerous factors, it is also exposed to trait selection and the niche filtering underlying the community. 4. An analysis of the relevance of body size to community organization in transitional water ecosystems in the eastern Mediterranean and Black Sea regions is presented, based on field research conducted on a sample of 15 transitional water ecosystems. 5. 250 taxa were identified, clumped in five orders of magnitude of body size. All body size patterns showed triangular distributions with an optimal size range of 0.13 mg to 1.0 mg individual body mass. 6. Deterministic components of size structure were emphasized and a hierarchical organization with dominance of large sizes was demonstrated by the slopes of the body size-abundance distributions, consistently larger than the EER threshold (b=,0.75), and by the direct relationship of energy use to body size for most of the body size range. 7. Consistent variations of body size-related descriptors were observed on three main gradients of environmental stress: eutrophication, confinement and metal pollution. 8. The results support the relevance of constraints imposed by individual body size on community organization in transitional water ecosystems and the adequacy of size patterns as an indicator for ecological conservation of these fragile ecosystems. Copyright © 2008 John Wiley & Sons, Ltd. [source] BEHAVIOR GENETICS AND ANOMIE/STRAIN THEORYCRIMINOLOGY, Issue 4 2000ANTHONY WALSH Criminology is in need of conceptual revival, and behavior genetics can provide the concepts and research design to accomplish this. Behavior genetics is a biologically-friendly environmental discipline that often tells us more about environmental effects on individual traits than about genetic effects. Anomie/strain theory is used to illustrate the usefulness of behavior genetics to criminological theories. Behavior genetics examines the individual differences that sort people into different modes of adaptation and that lead them to cope constructively or destructively with strain. Behavior genetics and other biosocial perspectives have the potential to help illuminate Agnew's (1997) extension of General Strain Theory (GST) into the developmental realm. [source] POWER AND POTENTIAL BIAS IN FIELD STUDIES OF NATURAL SELECTIONEVOLUTION, Issue 3 2004Erika I. Hersch Abstract The advent of multiple regression analyses of natural selection has facilitated estimates of both the direct and indirect effects of selection on many traits in numerous organisms. However, low power in selection studies has possibly led to a bias in our assessment of the levels of selection shaping natural populations. Using calculations and simulations based on the statistical properties of selection coefficients, we find that power to detect total selection (the selection differential) depends on sample size and the strength of selection relative to the opportunity of selection. The power of detecting direct selection (selection gradients) is more complicated and depends on the relationship between the correlation of each trait and fitness and the pattern of correlation among traits. In a review of 298 previously published selection differentials, we find that most studies have had insufficient power to detect reported levels of selection acting on traits and that, in general, the power of detecting weak levels of selection is low given current study designs. We also find that potential publication bias could explain the trend that reported levels of direct selection tend to decrease as study sizes increase, suggesting that current views of the strength of selection may be inaccurate and biased upward. We suggest that studies should be designed so that selection is analyzed on at least several hundred individuals, the total opportunity of selection be considered along with the pattern of selection on individual traits, and nonsignificant results be actively reported combined with an estimate of power. [source] Healthy, wealthy and insured?HEALTH ECONOMICS, Issue 3 2008The role of self-assessed health in the demand for private health insurance Abstract Both adverse selection and moral hazard models predict a positive relationship between risk and insurance; yet the most common finding in empirical studies of insurance is that of a negative correlation. In this paper, we investigate the relationship between ex ante risk and private health insurance using Australian data. The institutional features of the Australian system make the effects of asymmetric information more readily identifiable than in most other countries. We find a strong positive association between self-assessed health and private health cover. By applying the Lokshin and Ravallion (J. Econ. Behav. Organ 2005; 56:141,172) technique we identify the factors responsible for this result and recover the conventional negative relationship predicted by adverse selection when using more objective indicators of health. Our results also provide support for the hypothesis that self-assessed health captures individual traits not necessarily related to risk of health expenditures, in particular, attitudes towards risk. Specifically, we find that those persons who engage in risk-taking behaviours are simultaneously less likely to be in good health and less likely to buy insurance. Copyright © 2007 John Wiley & Sons, Ltd. [source] Evolution, origin and age of lineages in the Californian and Mediterranean florasJOURNAL OF BIOGEOGRAPHY, Issue 7 2009David D. Ackerly Abstract This paper addresses some of the conceptual issues involved in the analysis of the age and origin of mediterranean-climate plant taxa, paying particular attention to three topics: (1) the importance of an explicit time frame in the definition of biogeographical origins, (2) the distinction between the age of traits and the age of taxa, and (3) the idea of mediterranean-type ecosystems as environmental islands. (1) In California, recent analyses demonstrate that the diversity of species derived from different biogeographical origins is significantly correlated with temperature and precipitation gradients. These patterns support the hypothesis that niche conservatism is an important factor structuring modern diversity gradients. However, depending on how far back in time one looks, a species may be assigned to different origins; future discussions of biogeographical origins need to address the appropriate time frame for analysis. (2) Past research has demonstrated distinctive trait syndromes among woody plants of the Mediterranean, Chile, California and Mexico, and proposed that the syndromes are associated with lineages of different age in these floras. Reanalysis of individual traits demonstrates greater variability among regions than previously reported. The classification of plants into ,old' and ,new' genera is re-evaluated, and it is suggested that greater attention be paid to the age of traits, rather than to the age of taxa, especially at an arbitrary rank such as genus. (3) The idea of mediterranean-climate regions as ,climatic islands' is examined. Space,time diagrams of climate enable one to view the emergence of distinctive climatic regions in a continental context. The terms ,synclimatic' and ,anticlimatic' are proposed, referring to migration routes that parallel climate contours in space and time versus those that cross contours (including the case of geographic stasis in the face of climate change), respectively. Mediterranean-climate regions have served as important case studies in plant ecology and evolution, and merit continued close examination in the light of continued advances in phylogenetics and palaeoecology. [source] Explaining adult homelessness in the US by stratification or situationJOURNAL OF COMMUNITY & APPLIED SOCIAL PSYCHOLOGY, Issue 2 2003Michael R. Sosin Abstract In the US, the most widely accepted individual-level explanations of homelessness suggest that adults lose their dwellings when they cannot compete in the marketplace for the monetary resources needed to pay for housing, and cannot compete in a non-market struggle for compensatory resources. Such resource problems allegedly typically reflect myriad lifetime and current personal problems or deficits. However, the causal role of the problems and deficits is now known to be complex, and evidence about transitions in and out of homelessness suggests that key events occur somewhat independently of easily measured individual problems or deficits. This article, therefore, provides an alternative explanatory approach that directly focuses on aspects of the probabilistic situations that spur, or fail to reverse homelessness. The events and resource issues are posited to give rise to episodes of homelessness that vary in length, that are indirectly affected by many commonly mentioned individual traits, and that can be matched to targeted policies. Copyright © 2003 John Wiley & Sons, Ltd. [source] Fluctuating asymmetry of sexual and nonsexual traits in stalk-eyed flies: a poor indicator of developmental stress and genetic qualityJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2000Bjorksten It has been proposed that females use fluctuating asymmetry (FA) in sexual ornaments to assess male quality. FA of sexual traits is predicted to show greater sensitivity to stress than FA of nonsexual traits, and to be heritable. We used a half-sib mating design and manipulation of larval food environment to test these predictions on stalk-eyed flies, Cyrtodiopsis dalmanni, in which females prefer males with larger eyespans. We measured size and FA of eyestalks and of two nonsexually selected characters, wing length and width. We found no evidence of an increase in FA under larval food stress in any of the individual traits, although trait size decreased under stress. We combined FA across traits into a single composite index, and found that males reared in the most benign larval environment had significantly higher composite FA than males reared on other media. There was no such effect in females. Heritability of FA was not significantly different from zero in any of the traits, in any of the environments, although trait sizes showed high heritability. We conclude that FA in sexual and nonsexual traits is a poor indicator of developmental stress and genetic quality. [source] Dyadic Characteristics of Individual Attributes: Attachment, Neuroticism, and Their Relation to Marital Quality and ClosenessAMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 4 2005Adital Ben-Ari PhD The present article focuses on couple types based on 2 personality traits, attachment security and neuroticism, as they relate to 2 facets of the marital relationship,a global evaluation of relationship quality and dyadic closeness,distance. The sample consisted of 248 married couples who completed measures of attachment anxiety and avoidance, neuroticism, and marital quality, as well as levels of closeness reported over 7 consecutive days. Cluster analyses yielded 3 types of dyadic attachment configurations (secure, fearful avoidant, and insecure-mixed) and 4 types of dyadic neuroticism (low couple neuroticism, high couple neuroticism, wife neuroticism, and husband neuroticism). Significant differences were found among attachment and neuroticism dyadic types in marital quality. The findings are discussed in terms of the viability of dyadic types based on individual traits, implying that attachment security yields itself to dyadic conceptualization more than neuroticism. [source] Genetic and environmental contributions to variation in baboon cranial morphologyAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2010Charles C. Roseman Abstract The development, function, and integration of morphological characteristics are all hypothesized to influence the utility of traits for phylogenetic reconstruction by affecting the way in which morphological characteristics evolve. We use a baboon model to test the hypotheses about phenotypic and quantitative genetic variation of traits in the cranium that bear on a phenotype's propensity to evolve. We test the hypotheses that: 1) individual traits in different functionally and developmentally defined regions of the cranium are differentially environmentally, genetically, and phenotypically variable; 2) genetic covariance with other traits constrains traits in one region of the cranium more than those in others; 3) and regions of the cranium subject to different levels of mechanical strain differ in the magnitude of variation in individual traits. We find that the levels of environmental and genetic variation in individual traits are randomly distributed across regions of the cranium rather than being structured by developmental origin or degree of exposure to strain. Individual traits in the cranial vault tend to be more constrained by covariance with other traits than those in other regions. Traits in regions subject to high degrees of strain during mastication are not any more variable at any level than other traits. If these results are generalizable to other populations, they indicate that there is no reason to suppose that individual traits from any one part of the cranium are intrinsically less useful for reconstructing patterns of evolution than those from any other part. Am J Phys Anthropol 143:1,12, 2010. © 2010 Wiley-Liss, Inc. [source] Empirical testing of a model of online store atmospherics and shopper responsesPSYCHOLOGY & MARKETING, Issue 2 2003Sevgin A. Eroglu This study empirically tests a model that proposes that the atmospheric cues of the online store influence shoppers' emotional and cognitive states, which then affect their shopping outcomes. The results support the model propositions and show a significant effect of site atmospherics on shopper attitudes, satisfaction, and various approach/avoidance behaviors as a result of the emotions experienced during the shopping episode. In addition, the findings confirm the hypothesized moderating effects of two individual traits, namely, involvement and atmospheric responsiveness. The results underscore the role that online store atmospherics play in creating positive reactions from shoppers and demonstrate that these positive reactions will be more pronounced under certain conditions. © 2003 Wiley Periodicals, Inc. [source] Multivariate Association Test Using Haplotype Trend RegressionANNALS OF HUMAN GENETICS, Issue 4 2009Yu-Fang Pei Summary Genetic association analyses with haplotypes may be more powerful than analyses with single markers, under certain conditions. Furthermore, simultaneously considering multiple correlated traits may make use of additional information that would not be considered when analyzing individual traits. In this study, we propose a haplotype based test of association for multivariate quantitative traits in unrelated samples. Specifically, we extend a population based haplotype trend regression (HTR) approach to multivariate scenarios. We mainly focused on bivariate HTR, and the simulation results showed that the proposed method had correct pre-specified type-I error rates. The power of the proposed method was largely influenced by the size and source of correlation between variables, being greatest when correlation of a specific gene was opposite in sign to the residual correlation. [source] New Powerful Approaches for Family-based Association Tests with Longitudinal MeasurementsANNALS OF HUMAN GENETICS, Issue 1 2009Xiao Ding Summary We discuss several new powerful family-based approaches for testing genetic association when the traits are obtained from longitudinal or repeated measurement studies. The popular approach FBAT-PC is based on a linear combination of the individual traits. We propose a one-sided modification, FBAT-PCM, which has a closed-form expression and is always more powerful. We also present two approaches FBAT-LC and FBAT-LCC based on linear combination of the univariate test statistics. Furthermore, all three approaches are shown to be unified to a general form. Through simulation studies, we compare the power of these tests under different models of genetic effect sizes. Compared to original FBAT-PC, our modification achieves a power gain of up to 50%. In addition, all three new approaches gain substantial power compared to the ordinary approach of Bonferroni correction, with the relative performance depending upon the underlying model. Application of these approaches for testing an association between Body Mass Index and a previously reported candidate SNP confirms our results. [source] Traits, neighbors, and species performance in prairie restorationAPPLIED VEGETATION SCIENCE, Issue 3 2010R.E. Roberts Abstract Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon, USA. Methods: Twenty-eight native species, representing three functional groups, were sown in seven different combinations. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and regression techniques used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity; the functional group identity of neighboring species also influenced species' cover and the relationships between traits and cover. Species' establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi-trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 d and seed mass were strongly related to cover. Conclusions: Multiple-trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species and the other species being sown may need to be taken into account when making predictions. [source] | ||||||||||||||||