Phenotypic selection in a population of Crepis tectorum ssp. pumila (Asteraceae)

1992 ◽  
Vol 70 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Stefan Andersson
Keyword(s):  
Life History ◽  
Multiple Regression ◽  
Large Scale ◽  
Demographic Data ◽  
Phenotypic Selection ◽  
Direct Selection ◽  
Surprising Result ◽  
Regression Analyses ◽  
Ecotypic Differentiation ◽  
Crepis Tectorum

A 3-year demographic study was conducted to reveal targets of selection on morphology and life history in a population of Crepis tectorum ssp. pumila, a winter annual plant confined to calcareous grasslands (alvars) on the Baltic island of Öland (south Sweden). I calculated the selection differential to describe the change in the mean value of a character due to selection and used multiple regression analyses to partition the direct effect of selection on the trait from indirect responses of selection on other traits. Rosette leaf number, a convenient measure of plant size, was strongly correlated with both viability and fertility (fitness). There was also a strong relationship between fitness and the extent to which the plants expressed traits characterizing this particular taxon. Multiple regression analyses indicated direct selection favouring plants with deeply lobed leaves and a densely branched stem, two distinctive traits of ssp. pumila believed to be adaptive in the alvar habitat. Only stem height was subject to both direct and indirect selection in the wrong direction; taller individuals were more successful than those with a shorter stem, a surprising result considering the inferred advantage of a short stature in the exposed alvar habitat. Selection on other traits assumed to be ecologically important (germination time, flowering time, and seed size) was found to be either absent or variable in direction when other traits were held constant. The failure of plants to survive to the flowering stage in the last two summers indicates strong selection for plants that produce a high percentage of dormant seeds. Overall, the contemporary selection regime as revealed by demographic data was only partly congruent with predictions regarding historical selection pressures based on large-scale patterns of variation (ecotypic differentiation). Key words: Crepis tectorum, ecotypic differentiation, life history, morphology, phenotypic selection.

scholarly journals A multiple regression analysis of syntactic and semantic influences in reading normal text

2008 ◽  
Vol 2 (1) ◽  
Author(s):  
Joel Pynte ◽  
Boris New ◽  
Alan Kennedy
Keyword(s):  
Multiple Regression ◽  
Latent Semantic Analysis ◽  
Large Scale ◽  
Semantic Analysis ◽  
Regression Analyses ◽  
Length Frequency ◽  
Semantic Constraints ◽  
Normal Text ◽  
Two Measures ◽  
Syntactic Properties

Semantic and syntactic influences during reading normal text were examined in a series of multiple regression analyses conducted on a large-scale corpus of eyemovement data. Two measures of contextual constraints, based on the syntactic descriptions provided by Abeillé, Clément et Toussenel (2003) and one measure on semantic constraint, based on Latent Semantic Analysis, were included in the regression equation, together with a set of properties (length, frequency, etc.), known to affect inspection times. Both syntactic and semantic constraints were found to exert a significant influence, with less time spent inspecting highly constrained target words, relative to weakly constrained ones. Semantic and syntactic properties apparently exerted their influence independently from each other, as suggested by the lack of interaction.

Language and Literacy Predictors of Dialect Density Among School-Age African American Children From Two Geographic Regions

2020 ◽  
Vol 51 (3) ◽  
pp. 807-820
Author(s):  
Lena G. Caesar ◽  
Marie Kerins
Keyword(s):  
African American ◽  
Multiple Regression ◽  
Oral Language ◽  
East Coast ◽  
Geographic Region ◽  
Literacy Skills ◽  
School Age ◽  
Regression Analyses ◽  
Geographic Regions ◽  
American Children

Purpose The purpose of this study was to investigate the relationship between oral language, literacy skills, age, and dialect density (DD) of African American children residing in two different geographical regions of the United States (East Coast and Midwest). Method Data were obtained from 64 African American school-age children between the ages of 7 and 12 years from two geographic regions. Children were assessed using a combination of standardized tests and narrative samples elicited from wordless picture books. Bivariate correlation and multiple regression analyses were used to determine relationships to and relative contributions of oral language, literacy, age, and geographic region to DD. Results Results of correlation analyses demonstrated a negative relationship between DD measures and children's literacy skills. Age-related findings between geographic regions indicated that the younger sample from the Midwest outscored the East Coast sample in reading comprehension and sentence complexity. Multiple regression analyses identified five variables (i.e., geographic region, age, mean length of utterance in morphemes, reading fluency, and phonological awareness) that accounted for 31% of the variance of children's DD—with geographic region emerging as the strongest predictor. Conclusions As in previous studies, the current study found an inverse relationship between DD and several literacy measures. Importantly, geographic region emerged as a strong predictor of DD. This finding highlights the need for a further study that goes beyond the mere description of relationships to comparing geographic regions and specifically focusing on racial composition, poverty, and school success measures through direct data collection.

scholarly journals Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments

2021 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E. Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll
Keyword(s):  
Life History ◽  
Large Scale ◽  
Life History Traits ◽  
Genetic Correlations ◽  
Stress Factors ◽  
Life History Trait ◽  
Adaptive Landscape ◽  
Heterogeneous Environments ◽  
Growth Responses ◽  
Trade Offs

AbstractThe adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen’s ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.

scholarly journals The Gut Microbiota of Healthy Aged Chinese Is Similar to That of the Healthy Young

mSphere ◽  
2017 ◽  
Vol 2 (5) ◽  
Author(s):  
Gaorui Bian ◽  
Gregory B. Gloor ◽  
Aihua Gong ◽  
Changsheng Jia ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Data Analysis ◽  
Gut Microbiota ◽  
Large Scale ◽  
Compositional Data ◽  
Healthy Lifestyle ◽  
Compositional Data Analysis ◽  
Surprising Result ◽  
Microbiota Composition ◽  
Cross Sectional ◽  
Age Cohorts

ABSTRACT We report the large-scale use of compositional data analysis to establish a baseline microbiota composition in an extremely healthy cohort of the Chinese population. This baseline will serve for comparison for future cohorts with chronic or acute disease. In addition to the expected difference in the microbiota of children and adults, we found that the microbiota of the elderly in this population was similar in almost all respects to that of healthy people in the same population who are scores of years younger. We speculate that this similarity is a consequence of an active healthy lifestyle and diet, although cause and effect cannot be ascribed in this (or any other) cross-sectional design. One surprising result was that the gut microbiota of persons in their 20s was distinct from those of other age cohorts, and this result was replicated, suggesting that it is a reproducible finding and distinct from those of other populations. The microbiota of the aged is variously described as being more or less diverse than that of younger cohorts, but the comparison groups used and the definitions of the aged population differ between experiments. The differences are often described by null hypothesis statistical tests, which are notoriously irreproducible when dealing with large multivariate samples. We collected and examined the gut microbiota of a cross-sectional cohort of more than 1,000 very healthy Chinese individuals who spanned ages from 3 to over 100 years. The analysis of 16S rRNA gene sequencing results used a compositional data analysis paradigm coupled with measures of effect size, where ordination, differential abundance, and correlation can be explored and analyzed in a unified and reproducible framework. Our analysis showed several surprising results compared to other cohorts. First, the overall microbiota composition of the healthy aged group was similar to that of people decades younger. Second, the major differences between groups in the gut microbiota profiles were found before age 20. Third, the gut microbiota differed little between individuals from the ages of 30 to >100. Fourth, the gut microbiota of males appeared to be more variable than that of females. Taken together, the present findings suggest that the microbiota of the healthy aged in this cross-sectional study differ little from that of the healthy young in the same population, although the minor variations that do exist depend upon the comparison cohort. IMPORTANCE We report the large-scale use of compositional data analysis to establish a baseline microbiota composition in an extremely healthy cohort of the Chinese population. This baseline will serve for comparison for future cohorts with chronic or acute disease. In addition to the expected difference in the microbiota of children and adults, we found that the microbiota of the elderly in this population was similar in almost all respects to that of healthy people in the same population who are scores of years younger. We speculate that this similarity is a consequence of an active healthy lifestyle and diet, although cause and effect cannot be ascribed in this (or any other) cross-sectional design. One surprising result was that the gut microbiota of persons in their 20s was distinct from those of other age cohorts, and this result was replicated, suggesting that it is a reproducible finding and distinct from those of other populations.

THE EVALUATION OF SELF-MONITORING ATTRIBUTES

1991 ◽  
Vol 19 (3) ◽  
pp. 205-215 ◽  
Author(s):  
Arts Jiujias ◽  
Peter Horvath
Keyword(s):  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Regression Analyses ◽  
Self Monitoring

Eighty-six Canadian female undergraduates attributed self-monitoring traits to a target presented on videotape, and evaluated her in terms of liking. Attributed self-monitoring was negatively correlated with attraction to the target and was the only predictor of attraction in a multiple regression analysis. Multiple regression analyses with subscales of attributed self-monitoring as predictors suggested that the evaluations may be the result of the attributed unpredictability of the high self-monitoring prototype.

scholarly journals Genome size correlates with reproductive fitness in seed beetles

2015 ◽  
Vol 282 (1815) ◽  
pp. 20151421 ◽  
Author(s):  
Göran Arnqvist ◽  
Ahmed Sayadi ◽  
Elina Immonen ◽  
Cosima Hotzy ◽  
Daniel Rankin ◽  
...  
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Genome Size ◽  
Evolutionary Biology ◽  
Large Scale ◽  
Life History Traits ◽  
Single Species ◽  
Reproductive Fitness ◽  
Correlated Evolution ◽  
Seed Beetles

The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the ‘ C -value paradox’. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4–5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.

Copying, Reading, and Writing of Kana and Simple Forms by Japanese Preschoolers

1988 ◽  
Vol 66 (2) ◽  
pp. 387-394
Author(s):  
Jun Yamada ◽  
Miyuki Sasaki ◽  
Naoko Motooka
Keyword(s):  
Multiple Regression ◽  
Good Predictor ◽  
Quality Measure ◽  
Writing Achievement ◽  
Regression Analyses ◽  
Reading And Writing ◽  
Conventional Form ◽  
Form Quality ◽  
Japanese Kana ◽  
Children's Reading

42 Japanese preschoolers were administered tasks of copying, reading, and writing of Japanese kana (cursive syllabic letters) and simple forms. Multiple regression analyses were used to determine whether two kana-copying measures, speed and span, make significant contributions to children's reading and writing achievement after a conventional form-quality measure had been controlled. Analysis showed that speed or span accounts uniquely for a significant and sizable amount of the variance of reading and writing, suggesting that kana-copying is a good predictor of reading and writing for Japanese preschoolers.

Relationship Between Spirituality and Distress in Ascetics

2021 ◽  
pp. 003329412110434
Author(s):  
Rudra B. Bhandari ◽  
Nidhi Chaudhry ◽  
Sarita Devi
Keyword(s):  
Multiple Regression ◽  
Negative Relationship ◽  
Spiritual Intelligence ◽  
Self Report ◽  
Regression Analyses ◽  
Psychosomatic Health ◽  
Spirituality And Health ◽  
Medical Index ◽  
The Relationship ◽  
Health Questionnaires

The relation between spirituality and health has been argued for decades. The study aimed to ascertain the extent and nature of the relationship between spirituality quantified in terms of Spiritual Intelligence (SI) and distress in ascetics. Sixty-three Hindu ascetics aged 31.3 ± 6.6 years were sampled from Patanjali Yogpeeth, India. Participants’ distress and spiritual levels were measured by using the Cornell Medical Index Health Questionnaires (CMHIQs) and Spiritual Intelligence Self-Report Inventory-24 (SISRI-24), respectively. Multiple regression analyses showed an insignificant negative relationship between SI and distress implying SI as a predictor of psychosomatic health.

Predictors of quality of life and functioning in schizophrenia

2021 ◽  
Vol 25 (4) ◽  
pp. 341-356
Author(s):  
Octavia Căpățînă ◽  
◽  
Cristina Pojoga ◽  
Bogdan Savu ◽  
Mihaela Fadgyas-Stănculete ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Multiple Regression ◽  
Predictive Factors ◽  
Negative Symptoms ◽  
Clinical Symptoms ◽  
Cross Sectional Study ◽  
Regression Analyses ◽  
Cross Sectional ◽  
General Functioning

Background: In order to pursue recovery, Quality of life (QoL) and general functioning in patients with schizophrenia are milestones that need to be addressed in the treatment of the disease. The major aim of the present study was to examine the relationship between QoL, functionality and symptoms, and clinical characteristics of the disease, and to identify whether the two domains of negative symptoms, avolition/apathy and diminished expression, are predictive factors for the quality of life and functionality in patients diagnosed with schizophrenia. In the present cross-sectional study, 87 patients diagnosed with schizophrenia completed a thorough battery of instruments evaluating: clinical symptoms, stigma, QoL, functionality, socio-demographic and clinical variables. Multiple regression analyses were performed to test the significance of predictor variables for QoL and functionality. Multiple regression analyses revealed that internalized stigma, depression, and excitement were significant predictors for the variability of QoL, and experiential deficit and cognitive symptoms were significant predictors of the variability of functioning. In patients with schizophrenia, functioning and quality of life are two related but different constructs. Even though they are strongly associated, they have different predictive factors. The clinical implication of these results is that both of these constructs should be assessed and that the strategies for improving them should be different.

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