rcomeau

9secondkox2 said:

zimmie said:

MacPro said:

I can't see what Apple could do?  If they improved the sensitivity wouldn't that just make measurements better for light skins too, thus maintaining the differential?  It's physics not bias. 

Not necessarily. All pulse oximeters use a measurement correction curve to convert from the amount of reflected light to an oxygenation percentage. That curve needs to change based on skin tone and possibly other characteristics we don’t even know about today (since only recently did a million people start carrying an oximeter around with them everywhere). Correcting the curve for darker skin would make readings for lighter skin less accurate, so it would need to be adjustable.

There should be a calibration setting. 

mikethemartian said:

MacPro said:

I can't see what Apple could do?  If they improved the sensitivity wouldn't that just make measurements better for light skins too, thus maintaining the differential?  It's physics not bias. 

I don’t know what wavelength of light they use for these but there probably is a range in the non visible spectrum that could be used where skin tone would be irrelevant.

Pulse oximetry depends on the differential absorbance of 2 (or more) different frequencies of IR light in the blood, specifically the oxygenated and deoxygenated haemoglobin. You can pick 2 IR wavelengths where the absorbance curves of oxi and de-oxi cross each other (typically pick one <700nm and one >800nm. Acquire relative intensity (changes in time) of both these wavelengths and you can fit them to a curve using something called the modified Beer-Lambert law to get an estimated change in blood oxygenation. You have to pick wavelengths that are on the right spots on the curve as well as what wavelengths of LED are actually available and affordable (only a new nm difference can mean a $1 LED or a $100LED due to the material in the LED that emits the light). This is not an easy problem to solve, other than blasting more light in, but you then run into concerns over heating the skin (absorbing IR light means conversion into heat) as well as power consumption and safety (too intense and you run the risk of eye damage if some fool stares into the back of the watch with the LEDs on. Not an easy fix.

22july2013 said:

Maybe the future of social media is one social media engine used exclusively by conservatives, and a different one used exclusively by socialists. Companies with a political agenda will use only one of these two engines, and they won't even advertise on the engine that doesn't suit their own political agenda. Neutral companies may never be allowed to advertise on either platform because they will be banned by each platform if they advertise on the other platform.

Basically, you have to pick your side before you can interact with anyone on the Internet. Ultimately, socialists will have their own nationwide VPN and conservatives will be forced to have their own too. This will finally bring peace to the Internet. At least nobody will argue about politics anymore because everyone will be on their own political VPN.

maciekskontakt said:

Still no macOS virtualization on Windows or Linux hosts regardless if old Intel or ARM. Go figure. So why would one want to run Windows on macOS? That must be very interesting reason if everything is there on Mac's and supposedly better.

mac_dog said:

Spoiled brats? I don’t know about this, as I don’t know the particular people involved. I’m glad some of you do. 

I agree this should be handled with immediate managers. They would take the responsibility if their division fails to meet productivity requirements. 

They should be required to prove their increased productivity from home vs office. Simple enough to do and it’s measurable. 

Both sides should be open to the scrutiny that’s required to make this a fair arrangement.