Are apps that use LSUIElement in their plist causing google account problems

From your iPhone go to Settings > Store and disable Automatic Downloads for Apps. You can elect to do the same for books or music.

Your sons can visit the App Store and download any app that you've already purchased without being charged, though they will have to know the login information for the Apple ID tied to your iTunes Store account.

The alternative is to specify that the applications be synced to their phones from within iTunes.

To sync downloaded apps to iPod touch, iPhone, or iPad: Connect your iPod touch, iPhone, or iPad to your computer.

In iTunes, select your device (below Devices), and then click the Apps button.

Select Sync Apps, and then select the apps you want to sync.

The operative term here is photoplethysmograph. It's the term for what your phone is acting as.

Basically, your blood vessels rhythmically dilate and contract with every heart beat. This is measurable as either a change in reflectance or transmittance (depending on how the photoplethysmograph is configured. In the case of your phone, it's measuring reflectance, as the light is adjacent to the camera.

In medical instruments, it's generally done with infrared light, because blood absorbs shortwave infrared more then red or white light, and your tissue is more transparent to infrared. However, there is no reason it wouldn't work with a phone camera.

If done properly, it should be as or more accurate then manual measurement. However, a phone is not a proper photoplethysmograph, so the realistic achievable accuracy is likely dependent on a number of factors, including camera performance, proximity of the illuminating LED to the camera lens, and the algorithm used to extract the pulse from the video return.

However, you need to be aware that all photoplethysmographs are very sensitive to mechanical movement. It is essential that you hold your finger as still as possible, and avoid moving the phone relative to the finger.