Recent comments in /f/askscience

kilotesla t1_j2u6omm wrote

Reply to How close does one need to bring two coloured lights together to perceive a compound colour effect? by romxza

The underlying physics of this is really the underlying physiology. The different cells in the retina are sensitive to different colors of light, and when we see a color it is because of the comparison between the responses of those different cells in the retina. So a simple way to describe that is that the two sources of light have to be close enough together that they look like one point of light to us, and then the color we see is the color of that light. In other words, it's determined by the resolution of our vision.

The resolution of our vision is partly determined by the density of receptors in the retina, but it's also determined by how well we can focus. If you have red and green LEDs right next to each other, some meters away, and you can still see them as two separate leds you could make them merge into one yellow light by either taking off your glasses if you need glasses to see them, or putting on glasses that are wrong for you, to make the view blurry. Or you could simply walk further away from them until you only see one point of light, and that you will see it as yellow.

A common place to see this effect is on a large, but not very high resolution television screen. If you get up very close to it you can see the individual pixels, and for many display technologies, you will see them as individual red, green, and blue pixels, rather than as a full range of colors including yellow. If you don't have an appropriate display where you can see that, you can use a magnifying glass with a higher resolution display, even a phone.

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Skootypuff_ t1_j2tpskz wrote

Reply to comment by [deleted] in Can the human body clear a HPV infection copletely? by Terradubia

Especially the cancers not advertised (ie not cervical cancer).

The same thing happened to a family member. HPV was dormant in her body for ~20 years. Found a lump on a lymph node that wasn't going away, turns out it was cancer. There were a few tumors in and around her neck, lost her thyroid too, but at least we didn't lose her. During her treatment is when we found out that it can be dormant in your body and that people can be carriers with no symptoms.

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Alwayssunnyinarizona t1_j2tho8n wrote

Reply to comment by [deleted] in Can the human body clear a HPV infection copletely? by Terradubia

There is no harm in getting vaccinated while sexually active. No need to abstain. It may even be helpful in clearing an active infection.

It is likely that someone previously infected with HPV will still get some residual benefit from vaccination, even if he or she has already been infected with one or more of the HPV types included in the vaccines.

...

But the vaccine also offers some protection for HPV-positive women, reducing cervical lesions by 17% and genital warts by 35%.

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