OpenSEM Forums
orangeU
Joined: 05/23/2021
Longitudinal Cholesky decomposition with contrast effect
Hi all,
I have negative DZ correlations across multiple ages and I read that there may be a way to account for this by including a contrast effect (representing possible effects of twins within a pair on one another) in the model. Could someone please share an openMx script that does this? I have an old Mx script (attached) that accounts for a contrast effect in a classic ACE model, but I don't know how to translate it to openMx or how to integrate it in a Cholesky analysis.
Benny
Joined: 05/15/2020
Benny
Joined: 05/15/2020
mxAlgebra input
Hello,
for a SEM model I have calculated the expected covariance matrix using the symbolic linear algebra functionalities of the `Ryacas` package. To use the expected covariance matrix to calculate some second order statistics, I'm wondering whether the `mxAlgebra` function accepts some sort of R objects/expressions? Or does it only accept the "raw" names of the `mxMatrix` objects? I'm grateful for any hint on the topic.
Thanks!
- Read more about mxAlgebra input
- 1 comment
- Log in or register to post comments
Leo
Joined: 01/09/2020
Questions about biometric LGC
Hi,
I'm performing biometric latent growth curve analysis with OpenMx and there a few open questions which I hope some of you might know the answer to. I have three cohorts of twins which are each surveyed three times and I am doing separate analysis of every cohort. Variation of age within cohort and wave (survey time point) is small, so I decided to feed waves into the model rather than ages (so the manifests are, phenotypes at t1, phenotype at t2 and phenotype at t3) which leads to my first question
- Read more about Questions about biometric LGC
- Log in or register to post comments
hpar
Joined: 03/30/2021
using t-values as input data in SEM
Hi all,
- Read more about using t-values as input data in SEM
- 2 comments
- Log in or register to post comments
yaning
Joined: 04/12/2019
Doubt with compare between saturated and ACE model
Hello, everyone:
I'm running a bivariate twin model to estimate the correlation between a continuous variable (BMI) and a binary variable (CHD).
I have two questions:
First, i fund the means between MZ and DZ twins are different, do i need to constrain them with the same value in the ACE model;
Second, the p value between the saturated model and ACE model was＜0.05, what does this mean. Can i use ACE model to estimate the genetic and environmental correlation.
Thank you so much for your help.
Qiuzhi Xie
Joined: 12/27/2018
Two or more environmental mediators in one model
In the ACEF model (F is an identified shared environment), is it possible to involve 2 or more identified shared environmental factors (as the mediators) in one model?
sppspp10
Joined: 02/05/2021
Decomposed ACE variances...now trying to run regressions
I am 100% new to twin data and OpenMx, and so far the tutorials and documentations have been **superbly** helpful!
I used this [genetic epi path specification annotated guide] (https://vipbg.vcu.edu/vipbg/OpenMx2/docs//OpenMx/latest/GeneticEpi_Path.html#ace-model-a-twin-analysis) to decompose the variances of ACE on a given phenotype (my DV).
Now, though, I need to run a regression and I can't figure out how to feed the ACE variances from above into the regressions. I assume I have to constrain the parameters somehow?
Qiuzhi Xie
Joined: 12/27/2018
OpenMx Scripts for Gene-Environment correlation (rGE)
Hi,
I currently need to examine the correlation between additive gene (A) and moderators (such as SES and home language exposure). However, I don't have the OpenMx scripts to conduct rGE (gene-moderator correlation). Can anyone here provide me with an example script of rGE or tell me where I can find such scripts? I would be grateful very much!
valentinav
Joined: 06/15/2020
ACE, ADE or ACDE model
Hi All,
I saw papers in which they estimated ADE instead of ACE because the correlation between MZs was twice as big as the one for DZs.
So far in my analysis I used the ACE model, and I was wondering whether I should try the ACE one.
I also read of some analysis estimating ACDE model, is there any example twin I could look at?
Is the ACDE analysis impossible when twins are raised together?
Thank you very much for your help
- Read more about ACE, ADE or ACDE model
- 3 comments
- Log in or register to post comments