![Uncredited This cover image released by Avery Books shows "Practical Optimism: The Art, Science, and Practice of Exceptional Well-Being" by Sue Varma, MD. (Avery via AP)](https://mapi.associatedpress.com/v2/items/61bcd701bb134ce59bfe185f472d1984/preview/preview.jpg?s=680x&wm=false)
This cover image released by Avery Books shows "Practical Optimism: The Art, Science, and Practice of Exceptional Well-Being" by Sue Varma, MD. (Avery via AP)
![Kaoru Gleissner Hayami Koga, a postdoctoral research fellow at the Harvard Center for Population and Development Studies, poses for a portrait in Cambridge, Mass., on May 23, 2023. (Kaoru Gleissner via AP)](https://mapi.associatedpress.com/v2/items/02d1ae7ddfb64bab9e8d46ecfabbe41c/preview/preview.jpg?s=680x&wm=false)
Hayami Koga, a postdoctoral research fellow at the Harvard Center for Population and Development Studies, poses for a portrait in Cambridge, Mass., on May 23, 2023. (Kaoru Gleissner via AP)
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Prince Bhojwani sits on Charlies Bunion mountain along the Appalachian Trail in Great Smoky Mountains National Park in Tennessee on April 17, 2022. (Nita Bhojwani via AP)
![Kaoru Gleissner Hayami Koga, a postdoctoral research fellow at the Harvard Center for Population and Development Studies, poses for a portrait in Cambridge, Mass., on May 23, 2023. (Kaoru Gleissner via AP)](https://mapi.associatedpress.com/v2/items/d5a356716b7c4f1fbe6f092422f83881/preview/preview.jpg?s=680x&wm=false)
Hayami Koga, a postdoctoral research fellow at the Harvard Center for Population and Development Studies, poses for a portrait in Cambridge, Mass., on May 23, 2023. (Kaoru Gleissner via AP)