scholarly journals Heritability Coverage of Standard Biometric Models under various Phenotypic Architectures

2019 ◽  
Author(s):  
Michael Maraun ◽  
Moritz Heene ◽  
Philipp Sckopke
Keyword(s):  
Genetic Architecture ◽  
Covariance Matrices ◽  
Simulation Studies ◽  
Epistatic Interactions ◽  
Parameter Recovery ◽  
Genetic Environment ◽  
Recovery Performance ◽  
H2 Recovery ◽  
The Impact ◽  
Biometric Model

The behavioural scientist who requires an estimate of narrow heritability, h2, will conduct a twin study, and input the resulting estimated covariance matrices into a particular mode of estimation, the latter derived under supposition of the standard biometric model (SBM). It is now widely acknowledged that the standard biometric model can be expected to misrepresent, in manifold ways, the phenotypic (genetic) architecture of human traits. The impact of this misrepresentation on the accuracy of h2 estimation is unknown. Herein, we aimed to shed some light on this general issue, by undertaking three simulation studies. In each, the parameter recovery performance of five modes- Falconer's coefficient and the SEM models, ACDE, ADE, ACE, and AE- was investigated when they encountered a constructed, non-SBM, architecture, under a particular informational input. In study 1, the architecture was single-locus with dominance effects and genetic-environment covariance, and the input was { ΣMZ,T, ΣDZ,T, ΣMZ,A, ΣDZ,A}; in study 2, the architecture was identical to that of study 1, but the informational input was { ΣMZ,T, ΣDZ,T}; and in study 3, the architecture was multi-locus with dominance effects, genetic-environment covariance, and epistatic interactions. The informational input was {ΣMZ,T, ΣDZ,T, ΣMZ,A, ΣDZ,A}. The results suggest that conclusions regarding the coverage of h2 must be drawn conditional on a) the general class of generating architecture in play; b) specifics of the architecture’s parametric instantiations; c) the informational input into a mode of estimation; and d) the particular mode of estimation employed. In general, the results showed that more complicated the generating architecture, the poorer a mode’s h2 recovery performance. Random forest analyses furthermore revealed that, depending on the genetic architecture, h2, the dominance and locus additive parameter, and proportions of alleles were involved in complex interaction effects impacting on h2 parameter recovery performance of a mode of estimation. Data and materials: https://osf.io/aq9sx/

EpiPen: An R Package to Investigate Two-Locus Epistatic Models

2014 ◽  
Vol 17 (4) ◽  
Author(s):  
Raymond K. Walters ◽  
Charles Laurin ◽  
Gitta H. Lubke
Keyword(s):  
Power Analysis ◽  
R Package ◽  
Simulation Studies ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Epistatic Interactions ◽  
Model Interpretation ◽  
Genome Wide ◽  
Using Data ◽  
Power Analyses

Epistasis is a growing area of research in genome-wide studies, but the differences between alternative definitions of epistasis remain a source of confusion for many researchers. One problem is that models for epistasis are presented in a number of formats, some of which have difficult-to-interpret parameters. In addition, the relation between the different models is rarely explained. Existing software for testing epistatic interactions between single-nucleotide polymorphisms (SNPs) does not provide the flexibility to compare the available model parameterizations. For that reason we have developed an R package for investigating epistatic and penetrance models, EpiPen, to aid users who wish to easily compare, interpret, and utilize models for two-locus epistatic interactions. EpiPen facilitates research on SNP-SNP interactions by allowing the R user to easily convert between common parametric forms for two-locus interactions, generate data for simulation studies, and perform power analyses for the selected model with a continuous or dichotomous phenotype. The usefulness of the package for model interpretation and power analysis is illustrated using data on rheumatoid arthritis.

scholarly journals Investigating the Impact of Noneffortful Responses on Individual-Level Scores: Can the Effort-Moderated IRT Model Serve as a Solution?

2021 ◽  
pp. 014662162110138
Author(s):  
Joseph A. Rios ◽  
James Soland
Keyword(s):  
Classification Accuracy ◽  
Negative Impact ◽  
Parameter Recovery ◽  
Individual Level ◽  
Irt Model ◽  
Ability Estimates ◽  
Misclassification Rates ◽  
Individual Scores ◽  
3Pl Model ◽  
The Impact

Suboptimal effort is a major threat to valid score-based inferences. While the effects of such behavior have been frequently examined in the context of mean group comparisons, minimal research has considered its effects on individual score use (e.g., identifying students for remediation). Focusing on the latter context, this study addressed two related questions via simulation and applied analyses. First, we investigated how much including noneffortful responses in scoring using a three-parameter logistic (3PL) model affects person parameter recovery and classification accuracy for noneffortful responders. Second, we explored whether improvements in these individual-level inferences were observed when employing the Effort Moderated IRT (EM-IRT) model under conditions in which its assumptions were met and violated. Results demonstrated that including 10% noneffortful responses in scoring led to average bias in ability estimates and misclassification rates by as much as 0.15 SDs and 7%, respectively. These results were mitigated when employing the EM-IRT model, particularly when model assumptions were met. However, once model assumptions were violated, the EM-IRT model’s performance deteriorated, though still outperforming the 3PL model. Thus, findings from this study show that (a) including noneffortful responses when using individual scores can lead to potential unfounded inferences and potential score misuse, and (b) the negative impact that noneffortful responding has on person ability estimates and classification accuracy can be mitigated by employing the EM-IRT model, particularly when its assumptions are met.

scholarly journals A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works

2021 ◽  
Vol 13 (11) ◽  
pp. 5795
Author(s):  
Sławomir Biruk ◽  
Łukasz Rzepecki
Keyword(s):  
Simulation Model ◽  
Technological Process ◽  
Construction Projects ◽  
Working Time ◽  
Simulation Studies ◽  
Construction Methods ◽  
The Impact ◽  
Construction Works

Reducing the duration of construction works requires additional organizational measures, such as selecting construction methods that assure a shorter realization time, engaging additional resources, working overtime, or allowing construction works to be performed simultaneously in the same working units. The simultaneous work of crews may affect the quality of works and the efficiency of construction processes. This article presents a simulation model aimed at assessing the impact of the overlap period on the extension of the working time of the crews and the reduction of a repetitive project’s duration in random conditions. The purpose of simulation studies is to provide construction managers with guidelines when deciding on the dates of starting the sequential technological process lines realized by specialized working crews, for sustainable scheduling and organization of construction projects.

Detecting Noneffortful Responses Based on a Residual Method Using an Iterative Purification Process

2021 ◽  
pp. 107699862199436
Author(s):  
Yue Liu ◽  
Hongyun Liu
Keyword(s):  
True Positive Rate ◽  
Item Parameter ◽  
Parameter Estimates ◽  
Detection Accuracy ◽  
Purification Process ◽  
Parameter Recovery ◽  
Residual Method ◽  
Data Contamination ◽  
Item Parameters ◽  
The Impact

The prevalence and serious consequences of noneffortful responses from unmotivated examinees are well-known in educational measurement. In this study, we propose to apply an iterative purification process based on a response time residual method with fixed item parameter estimates to detect noneffortful responses. The proposed method is compared with the traditional residual method and noniterative method with fixed item parameters in two simulation studies in terms of noneffort detection accuracy and parameter recovery. The results show that when severity of noneffort is high, the proposed method leads to a much higher true positive rate with a small increase of false discovery rate. In addition, parameter estimation is significantly improved by the strategies of fixing item parameters and iteratively cleansing. These results suggest that the proposed method is a potential solution to reduce the impact of data contamination due to severe low test-taking effort and to obtain more accurate parameter estimates. An empirical study is also conducted to show the differences in the detection rate and parameter estimates among different approaches.

What We Don't Know About Diet-Breadth Evolution in Herbivorous Insects

2020 ◽  
Vol 51 (1) ◽  
pp. 103-122 ◽  
Author(s):  
Nate B. Hardy ◽  
Chloe Kaczvinsky ◽  
Gwendolyn Bird ◽  
Benjamin B. Normark
Keyword(s):  
Plant Species ◽  
Population Genetic ◽  
Genetic Architecture ◽  
Diet Breadth ◽  
Herbivorous Insects ◽  
Herbivorous Insect ◽  
Insect Diversity ◽  
Major Question ◽  
Genetic Environment ◽  
Species Ecology

Half a million species of herbivorous insects have been described. Most of them are diet specialists, using only a few plant species as hosts. Biologists suspect that their specificity is key to their diversity. But why do herbivorous insects tend to be diet specialists? In this review, we catalog a broad range of explanations. We review the evidence for each and suggest lines of research to obtain the evidence we lack. We then draw attention to a second major question, namely how changes in diet breadth affect the rest of a species’ biology. In particular, we know little about how changes in diet breadth feed back on genetic architecture, the population genetic environment, and other aspects of a species’ ecology. Knowing more about how generalists and specialists differ should go a long way toward sorting out potential explanations of specificity, and yield a deeper understanding of herbivorous insect diversity.

The effect of job insecurity on quitting intentions and service recovery performance

2019 ◽  
Vol 28 (2) ◽  
pp. 12-14
Keyword(s):  
Psychological Contract ◽  
Job Insecurity ◽  
Service Recovery ◽  
Mediating Effect ◽  
Full Time ◽  
Content Type ◽  
Career Opportunities ◽  
Service Recovery Performance ◽  
Recovery Performance ◽  
The Impact

Purpose The purpose of this study is to examine the impact of JIS on quitting intentions and service recovery performance (SRP) with JE as a mediating factor. Design/methodology/approach Data was gathered from 313 full time FHEs working in four and five star hotels in Iran. Questionnaires on JIS, JE, and quitting intentions were given in three waves to the FHEs over a two-week period and in addition supervisors provided a rating of SRP. Findings The findings support the mediating effect of JE with JIS related to the outcomes indirectly through JE. The greater the level of JIS the lower the JE of FHEs. The greater the level of JE the lower the quitting intentions and the higher the SRP of FHE’s. JE completely mediates the impact of JIS on quitting intentions and SRP. Practical implications Organizations should put steps in to retain key workers through adherence to the psychological contract, reduce the impact of JIS through providing clear information on career opportunities and progression, invest in high quality training to improve SRP and hire a workforce from the local communities to increase off-the job JE Originality/value This paper has contributed to an area where research is scarce with regard to how JIS can be reduced and the structure that links it to employee outcomes.

Simulation Studies of the Effect of Shaft's Nonlinear Flexural Stiffness Parameters for Critical States of Rotating Power Transmission Systems

2015 ◽  
Vol 236 ◽  
pp. 62-69
Author(s):  
Tomasz Matyja ◽  
Bogusław Łazarz
Keyword(s):  
Degrees Of Freedom ◽  
Power Transmission ◽  
Flexural Stiffness ◽  
Simulation Studies ◽  
Critical States ◽  
Rotating Machine ◽  
Power Transmission Systems ◽  
Main Component ◽  
6 Degrees Of Freedom ◽  
The Impact

The paper presents simulation studies, performed using Simulink, the impact of nonlinear flexural stiffness of shafts for critical speed range and amplitude of vibration. The tests were performed on the selected model of a rotating machine, consisting of a drive, two torsional vibration dampers, shaft with mounted on it two rigid rotors (discs), supported on a three self-aligning roller bearings and mechanical power receiver (brake). The machine startup and braking with crossing the critical states was simulated using specialized Simulink library, which was developed by authors for analysis of transient states in rotating machines and flexural-torsional couplings. In accordance with the concept of modeling adopted by the authors, rotating system is divided into inertial rigid elements (rotors, bearings, clutches, etc..) and compliance elements (parts of the shaft). The main component of the currently developed library is block modeling rigid rotor with 6 degrees of freedom and with the static and dynamic unbalance. By assumption the library is a modular, expandable and allows modeling the systems of any configuration. The goal of the simulation was to verify how nonlinear flexural stiffness of shaft influences the values of critical speeds and the level of flexural and torsional vibrations.

scholarly journals Genetic background influences the impact of KLOTHO deficiency

2020 ◽  
Vol 52 (10) ◽  
pp. 512-516
Author(s):  
Jawad S. Salloum ◽  
Diane E. Garsetti ◽  
Melissa B. Rogers
Keyword(s):  
Genetic Background ◽  
Genetic Architecture ◽  
Disease Susceptibility ◽  
Inbred Mouse ◽  
Mouse Strains ◽  
Disease Models ◽  
Inbred Mouse Strains ◽  
Metabolic Interactions ◽  
Klotho Protein ◽  
The Impact

Genetic background is a key but sometimes overlooked factor that profoundly impacts disease susceptibility and presentation in both humans and disease models. Here we show that deficiency of KLOTHO protein, an important renal regulator of mineral homeostasis and a cofactor for FGF23, causes different phenotypes in 129S1/SvlmJ (129) and C57BL/6J (B6) mouse strains. The 129 strain is more severely affected, with decreased longevity, decreased body weight, and increased amounts of kidney calcification compared with B6 mice. Reciprocal F1 crosses of the strains also indicate a parentage effect on the Klotho phenotype with F1 KLOTHO-deficient progeny of B6 mothers and 129 fathers having more kidney calcification than progeny of 129 mothers and B6 fathers. Comparing and contrasting the genetic architecture leading to different phenotypes associated with specific inbred mouse strains may reveal previously unrecognized and important metabolic interactions affecting chronic kidney disease.

scholarly journals THE EFFECT OF MANAGEMENT COMMITMENT TO SERVICE QUALITY ON JOB EMBEDDEDNESS AND PERFORMANCE OUTCOMES

2012 ◽  
Vol 13 (4) ◽  
pp. 614-636 ◽  
Author(s):  
Osman M. Karatepe ◽  
Georgiana Karadas
Keyword(s):  
Service Quality ◽  
Customer Service ◽  
Service Recovery ◽  
Job Embeddedness ◽  
Performance Outcomes ◽  
Quality Data ◽  
Management Commitment ◽  
Service Recovery Performance ◽  
Recovery Performance ◽  
The Impact

The purpose of this study is to develop and test a conceptual model that examines job embeddedness as a partial mediator of the impact of management commitment to service quality on service recovery performance and extra-role customer service. Training, empowerment, and rewards are regarded as the three important indicators of management commitment to service quality. Data were obtained from a sample of fulltime frontline hotel employees with a time lag of one week in Romania. The results reveal that training, empowerment, and rewards are positively related to job embeddedness. As hypothesized, empowerment, rewards, and job embeddedness enhance service recovery performance, while training and empowerment increase extra-role customer service. The results further demonstrate that job embeddedness acts as a partial mediator of the effects of empowerment and rewards on service recovery performance. Implications of the results are discussed and future research directions are offered.

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