<|begin_of_text|><|start_header_id|>system<|end_header_id|>

You are an expert at identifying data availability statements in scientific text. A data availability statement describes where research data can be found or how it can be accessed.<|eot_id|><|start_header_id|>user<|end_header_id|>

Determine if the following text contains a data availability statement. Answer with 'yes' or 'no'.

Text: data are from the na-accord cohort collaboration of iedea (international epidemiologic databases to evaluate aids), whose authors may be contacted at http://statepiaps.jhsph.edu/naaccord/collaboration/index.html. a concept sheet must be submitted, reviewed, and approved by the executive and steering committees of na-accord before data access/data sharing are allowed. this is a requirement of all participating cohort irb approvals, as well as the study umbrella irb approval from the johns hopkins university school of medicine, ensuring secure, timely, and ethical sharing of the cohort's data. due to ethical restrictions, data are available upon request. the na-accords data practices have been outlined in the literature (http://www.ncbi.nlm.nih.gov/pmc/articles/pmc2820873/). interested researchers may submit requests for data to the project manager, who will direct the collaborative process through the administrative, data management, and epidemiology/biostatistics cores (afreeman@jhu.edu).<|eot_id|><|start_header_id|>assistant<|end_header_id|>

yes<|eot_id|>