Epidemiology & Technology

Blog Archive

Postgres/ PostgreSQL 18 Docker containers

Postgres 18 is out. How to run it in containers easy Basic steps Backups Adding a new App specific Db and its specific db user Connection String

Public ReDash Dashboards with path based routing behind a Nginx reverse proxy

monitor screengrab
We had a use case where multiple ReDash dashboards were created. Some of the dashboards had to be made public. Login from public was to be disabled. We had a subdomain that was already serving few custom dashboards. Therefore the new rehash dashboards had to be served using path based

Sample Size for Diagnostic tests using R

Using SampleSizeDiagnostics package

McHose GX 87 Shortcuts

I switch between Mac and Windows on a McHose GX 87. Following are the shortcut keys to make life easy Bluetooth Device Switching Hold for 3 seconds to enter device pairing mode USB Dongle 2.4 GHz Pairing - Fn + Q - Hold for 3 seconds Fn + B :

Height of Tumbling E for Visual Acuity Assessments at various distances

person holding eyeglasses
When developing mobile apps / charts for assessing visual acuities using Snellen's / LogMAR notation, there is a need to estimate the size of letters for a given working distance for assessing a specific cutoff. Under normal vision, for a visual acuity of 6/6, the whole letter subtends an angle

Nginx Log Full URL in Reverse Proxy

If you run a NGINX reverse proxy hosting multiple services, you may need to see which access was for which service. The Access log can be modified to log the full URL as under

Sample size for Paired T test

Simple pre-post designs where the outcome assessed is continuous. Using pwrss package Output References

Resoucres for working with OCT images

Meta / reviews of datasets Datasets Tools Codes

Precision based Sample Size Calculation using precise in R

https://joss.theoj.org/papers/10.21105/joss.03118 https://ctu-bern.github.io/presize/ Verbatim From the article - There are two approaches for each measure. Proportion Shiny Webapp

Recommended Precision for Sample Size of Prevalence

Often people are confused about the precision that should be used when estimating sample size for prevalence studies. Some guidance here From: Sample size calculation for prevalence studies using Scalex and ScalaR calculators  Expected PrevalenceRecommended PrecisionLarge ScaleSmall ScalePreliminary StudyRemark110 to 90%2 ~ 3%4 ~ 5% > 5% 2 < 10%0.25*EP0.50*EP > 0.50*EPCannot be equal to EP or larger e.g. 4%1%2% > 2%Cannot be 4% or