Behavioral Genetics Models

Longitudinal modeling with extended twin design
I have a couple of questions regarding my research and I would really appreciate getting some feedback if my undertaking is reasonable.
I am investigating stability of a political phenotype in a two-wave panel design. I'm including not only twins in my analysis, but also one non-twin full sibling. The scripts are standing and working (verified with replication).

GxE with ordinal manifest in RAM
I'm trying to build a Purcell style GxE model in RAM. I have not found any script for this so I created it from scratch. Right now I have a two ordinal manifests (twin 1, twin 2, same phenotype, 4 cats, 3threshs). The moderator will be continuous in the end. However, right now for experimental reasons I have created a binary moderator (sex) for me to easily check if my model does produce accurate results.
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ACE output: what is the p
I run the ACE model and got a summary table which reports the p among others.
The p is also not clear to me. Apparently it is higher for the winning model, but what exactly is this p?
Thanks,
Valentina
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ACE RAM model with ordinal manifest
I've been trying everything to get an ordinal manifest working in RAM models but I can't get it done. Also, didn't find anything online about this, as most examples have matrix specification. Would be very appreciated to get some help. Besides from the solution below, I have also tried every possible way with mxthreshold and umxthresholdmatrix.
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really similar AIC
I run the ACE model and submodels, and the AIC are really similar.
ACE 2579
AE 2577.5
CE 2577.3
E 2584
Overall, I always get a difference of 1 between the AIC.
The best winning model is always coherent with the results of the correlation analysis, so I tend to trust it, however, the difference is really little.
Is there a way to establish what is a significant difference between AIC?
Thank you all!
Valentina
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ACE: negative variance component from H.Maes’ published script and slides
could you help provide some insights as to why running the following script, which uses data(twinData), gives negative estimates for Vc in an ACE model?
https://ibg.colorado.edu/cdrom2020/maes/twinModeling/oneACEvc.R
These are the most relevant lines related to the model:

Step 1: Testing basic assumptions (equal means & variances for twin 1/twin 2 and MZ/DZ pairs)
I am following the steps laid out in [this](https://vipbg.vcu.edu/media/course/HGEN619_2015/TwinModels.pdf ) openmx presentation and could use help with step 1.
1. Use data to test basic assumptions (equal means & variances for twin 1/twin 2 and MZ/DZ pairs)

ACE model lower CI negative number
I am new to ACE model estimation so I am trying to follow some tutorials I found online (script attached).
The results seems fine, and are also coherent with another script I used. However, I got negative lower CI: ACEvc.VarC[1,4] -0.2443061 0.23255753 0.7557620.
Does this make sense to you? As far as I know when CI include 0 we cannot conclude that the value is different from 0...
I would really appreciate whether someone could help me with this.
Thank you in advance!
Best,
Valentina
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