I know this 'rule' in the context of cars, but I assume also true for airplanes and boats. Why is this the case? Its not like refuelling opens the combustion chamber... And if fumes are the ones in danger to ignite, couldn't that happen from the petrol in the tank anyway? Excuse my poor knowledge of internal combustion engines !
Edit: Thanks for all the answers. To simplify, I will make a clarification before going to sleep; for a car in a gas station, what would cause ignition? The electrical wiring? The buildup of static charge? The heat in the engine components? Or the engine's combusting? ... For a brand new car what would be the main danger, and how has this changed over the years i.e. by using different materials / engine design?
I was looking through the adverse reactions to the COVID vaccines, and I found it interesting that the CDC report that younger people are more likely to experience (or at the very least report) an adverse reaction to the COVID vaccines than if you were older. I would have thought it would be the opposite (due to older people having weaker immune systems)? Can someone explain this phenomenon? Is this something of all vaccines? What's the biological mechanism here?
Refer to table 1 of https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e3.htm: 64.9% of 18 to 49 report an adverse reaction. I thought perhaps it was to do with unequal category sizes (18 to 49, versus say 50 to 64), but I don't think it is as this represents 2/3 of the total.
P.S. I really don't want to get into a debate about whether or not people should take the vaccine or not (I think people at risk, definitely should). I simply want to understand why vaccines effect different age groups in different ways.
(For some reason moderators removed this post... This is a legitimate medicinal question, but for some reason I'm not even allowed to ask it)
I'm not fully informed on the topic, but to my understanding, EU banned certain pesticides and the US have not.
What's the 2021 situation on pollinators in the EU vs the US?
2Why doesn't it attack and try to destroy the implant like it does with other foreign bodies?
Edit: thank you all so much for taking the time to answer my question! I've loved reading all your responses and I've learned loads (the WW2 doctor thing and how different patients/body parts respond is so fascinating). I'm just starting my immunology units at university, and I can't wait to hear more about everything you guys have mentioned!
With COVID-19 cases on the rise once again, one thing that has become clear is the fact that nearly all patients who are hospitalized as a result of infection with the Delta variant of SARS-CoV-2 have not yet received any form of immunization against the virus. However, what's less obvious is the likelihood of hospitalization between relevant strains of the virus among unvaccinated comparable populations. Have there been any reviews that have looked into differences in hospitalization risk between these variants?
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