1 In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured. To increase their accuracy, mercury barometers are often corrected for ambient temperature and the local value of gravity.
If you think you may have been infected with HIV/AIDS, please find a place to get a free, confidential HIV test. You can have HIV and not have any symptoms, and some HIV tests will not show a positive result for as long as 3 months after infection. This is referred to as the HIV test window period, and has to do with how HIV tests detect the virus. Some people recently infected with HIV will experience some flu-like symptoms. These might include: 1  Fever. 2  Severe Fatigue. 3  A non-itchy rash. 4  Swollen glands/lymph nodes. 5  Muscle aches. 6  Sore throat. 7  Night sweats.
There are three stages of HIV infection. Stage 1 after initial infection can feel like flu, but not everyone will experience this. Stage 2 may last for 10 years or so, with no more apparent symptoms.