Recent comments in /f/askscience

bullwinkle8088 t1_j7dudfm wrote

Reply to comment by CrustalTrudger in Is there a term for lake bottoms that "hour glass" (temporarily becomes wider following a "shelf" as the depth increases ) , how do bathymetric maps depict this, and does this have a common affect on turbidity, thermoclines, or other characters? by Irisgrower2

Here is what I get from this: Picture a nice round lake at the surface shaped like a vertical hourglass in depth, thats is the "gets wider" part and what i think OP is asking about.

it is an interesting question, and is a quite possible shape. The first thing that comes to mind is the lake in Louisiana that flooded a salt dome underneath it, generating not an hourglass shape but a huge flooded cavern under the lake. This is at least a similar layout to the question.

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Indemnity4 t1_j7dldsx wrote

Reply to comment by Hidden_Armadillo in Why do some allergies get worse over time and some better? And how does allergen desensitivity work without making the reaction worse? by DontDoDrugs316

Non-celiac gluten sensitivity - Yes. Allergen specific immunotherapy. You wait 1-2 years on a gluten-free (or close enough) diet then slowly start to re-introduce low amounts of gluten.

Celiac - no. Studies trying antigen-specific immunotheraphy have all failed. Those people are usually missing an important gene in their DNA - difference from above is it was never working, not that it went bad over time and needs help recovering. Most future therapies are targeting the immune system response itself and silencing or inhibiting some part of the process.

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Once_Wise t1_j7djz9p wrote

Reply to comment by kmoonster in Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

>Combine this with a sense of how quickly the sun moves, and you can work out useful light after dark fairly easily. The sun moves through about 15 degrees of arc in an hour, and there are discernible amounts of useful light up to at least 18 degrees of arc below the horizon, sometimes more depending on weather -- and you can have well in excess of an hour before/after the sun is visible. Perhaps two hours or even more. And if the area has an open tree canopy, stars provide a fair amount of light if they are visible.

It is surprising to us city folks like me how much one can see by starlight alone. I have done a fair amount of camping in the California deserts, and it is amazing how bright a moonless starlit night can be. Several times I have been able to walk along a dirt road by starlight alone. About 3am, your eyes are used to the dark, you cannot make out any clear features but there are no trees, the ground is relatively light colored and while it would be dangerous to walk cross country, I have done it on a dirt desert road at night. It was BLM land where you can camp and find spots with no other people for miles around. On other moonlit nights I have read a newspaper inside my tent after my eyes were used to the dark. I imagine that people in days when there was very little artificial light, and where they had grown up and were used to these conditions and their surroundings, could do quite well at night. And most nights have at least some moonlight. I learned this quite early when our former Marine, Boy Scout leader made us leave our flashlights back in camp and took us on night hikes, navigating by moonlight alone. Along the way he would stop and tell scary stories. But that was ages ago. Fear of lawsuits would probably prohibit this kind of thing today.

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AllenRBrady t1_j7dim8j wrote

Reply to comment by AllenRBrady in Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

I just wanted to throw in a few calculations to round this theory out a bit. Looking at Mannheim, Germany, I see that the winter solstice this year will have 8 hours and 9 minutes of daylight, and the summer solstice will have 16 hours and 17 minutes. That means the winter night will last 951 minutes, and the summer night only 463. If we divide that into 12 hours, that makes a winter hour as long as 79.25 minutes, and a summer hour as short as 38.58 minutes.

So 8pm in the winter would translate to 158.5 minutes past Vespers (sunset), and 10pm in the summer would mean 154.3 minutes past Vespers. That's pretty consistent. If my speculation is correct, this law is saying you need to carry a light source if you're leaving your house 2.5 (modern) hours after sunset.

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znark t1_j7d86bp wrote

Reply to Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

There is also Gregorian calendar reform to consider. The calendar had shifted from the seasons because of inaccuracy of the Julian calendar. It was 10 days in 1582 when the most of Catholic countries adopter new calendar. I think Palatinate was Protestant and transitioned in 1700.

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Only_Philosopher7351 t1_j7cuvun wrote

Reply to Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

Although keeping time is a human invention and was only agreed upon relatively recently, variations in the earth's wobble around its axis have lead to shorter and longer amounts of sunlight further away from the equator.

But these variations are part of a long cycle (Milankovitch cycles) on observatories like Newgrange and Stonehenge prove that the position of the sun in the northern hemisphere has been very consistent for the last 10,000 or so years.

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the_fungible_man t1_j7csiu8 wrote

Reply to How does shingles cause a rash when the infection is located all the way in the dorsal ganglia? by menooby

The varicella zoster virus (VZV) can lie dormant in the dorsal root ganglia for decades after the immune system has cleared the virus from the rest of the body (from an initial chickenpox infection).

However, once reactivated, the VZV resumes replication and virions are transported through neural cells from the ganglia into the associated skin area. The subsequent immune response produces localized inflammation, blistering, and pain.

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GiverOfUseless t1_j7crm69 wrote

Reply to comment by iayork in Did the 2009 H1N1 outbreak in the US increase the incidence of type 1 diabetes in adolescents? by legendary_kazoo

What I have heard from one of my teachers is that Covid “caused” an increase in type 1 diabetes as normally it is revealed through a virus that causes stress to the immune system so then type 1 diabetes “appears” because it was going to eventually it just activated it early

Based on this I do believe that H1N1 would cause an “increase” in type 1 diabetes as it revealed it

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Traditional_Story834 t1_j7chmfy wrote

Reply to Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

They are fairly consistent but will vary over time and would not be the exact same every year. It depends on the time scale you choose. The differences are small in the year to year. Main thing to check out is precession, it takes the earth 26,000 years to complete one precession, part of the yearly difference you see. Also things like large earthquakes tend to speed up the rotation, think a figure skater pulling their arms to their body during a spin.

Another thing I would consider is the fact time zones didn't exist back then like now, not sure you could confirm their 8 and 10 pm were in fact the same 8 and 10 pm they experience today as time zones didn't exist until after the 1880s.

Also the time they would need light will vary between those two times in the evening as they represent the extremes between the two seasons. So at the height of summer your good until 10pm, the bottom of winter you need it at 5pm, but in the middle of fall you might need it at 7:30pm.

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