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  2. History of radio - Wikipedia

    en.wikipedia.org/wiki/History_of_radio

    The invention of the superheterodyne receiver solved this problem, and the first radios with a heterodyne radio receiver went for sale in 1924. But it was costly, and the technology was shelved while waiting for the technology to mature, and in 1929 the Radiola 66 and Radiola 67 went for sale.

  3. Timeline of radio - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_radio

    The timeline of radio lists within the history of radio, the technology and events that produced instruments that use radio waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history .

  4. History of Ohio - Wikipedia

    en.wikipedia.org/wiki/History_of_Ohio

    [130] [131] A 2016 study on immigrants in Ohio concluded that immigrants make up 6.7% of all entrepreneurs in Ohio although they are just 4.2% of Ohio's population, and that these immigrant-owned businesses generated almost $532 million in 2014. The study also showed that "immigrants in Ohio earned $15.6 billion in 2014 and contributed $4.4 ...

  5. Invention of radio - Wikipedia

    en.wikipedia.org/wiki/Invention_of_radio

    Before the discovery of electromagnetic waves and the development of radio communication, there were many wireless telegraph systems proposed and tested. [4] In April 1872 William Henry Ward received U.S. patent 126,356 for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire. [5]

  6. Radiology - Wikipedia

    en.wikipedia.org/wiki/Radiology

    Radiology is a five-year post-graduate program that involves all fields of radiology with a final board exam. France To become a radiologist, after having validated the common core of medical studies, one must obtain a DES (Specialized Studies Diploma) in radiology and medical imaging (specialized studies in 5 years), or a DES in advanced ...

  7. AOL Mail

    mail.aol.com

    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  8. Timeline of scientific discoveries - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_scientific...

    The timeline begins at the Bronze Age, as it is difficult to give even estimates for the timing of events prior to this, such as of the discovery of counting, natural numbers and arithmetic. To avoid overlap with timeline of historic inventions , the timeline does not list examples of documentation for manufactured substances and devices unless ...

  9. Timeline of medicine and medical technology - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_medicine_and...

    500 BC – Pills were used. They were presumably invented so that measured amounts of a medicinal substance could be delivered to a patient. 510–430 BC – Alcmaeon of Croton scientific anatomic dissections. He studied the optic nerves and the brain, arguing that the brain was the seat of the senses and intelligence.