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rhinokungfu

52 karma · joined March 11, 2016

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rhinokungfu··on Surviving the coronavirus, then testing positive again
As per this paper - https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767. Both increase in temperature and humidity reduces the transmission of COVID-19.

Abstract: This paper investigates how air temperature and humidity influence the transmission of COVID-19. After estimating the serial interval of COVID-19 from 105 pairs of the virus carrier and the infected, we calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of non-intervened transmission intensity, we find, under a linear regression framework for 100 Chinese cities, high temperature and high relative humidity significantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities. One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively. This result is consistent with the fact that the high temperature and high humidity significantly reduce the transmission of influenza. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19.

rhinokungfu··on Toyota invests $394m in Joby Aviation's flying taxis
True, Hydrogen has a far higher energy density than li-ion batteries (~150x). But that doesn't show the entire picture. To store and use that hydrogen, you also need a very strong tank (cause of the high pressure it has to be stored in a vehicle) and a fuel cell stack to generate electrical energy. Taking the example of Toyota's Mirai, the hydrogen tank weighs 90kg to just store 5kg of Hydrogen (at 700bar). And this is despite being made of very expensive carbon fibre. If it was made of cheaper but heavier materials like steel, it would weigh much more. And the fuel cell in Mirai weighs 60kg just to output 114kw (155hp). Add all this up and it is a much more even (~2x, not ~150x) comparison with Li-ion battery (for reference Model 3 battery weighs 480kg). And given all this, not surprising the Mirai weighs (1850kg) more than a Model 3 long range (1725kg) despite having similar range and being far less powerful.
rhinokungfu··on If the universe is 13.8B years old, how can we see 46B light years away? (2018)
Posted this to a point above, but probably more pertinent here, so reposting - Some of the confusion is, I think from referring to speed of light as "speed of light". When it really is speed limit of causality between 2 points in space. And light (em waves) just happen to be able to hit that limit. Now since expansion of space is itself not going to allow one point in space to cause any effect on another, it (the expansion) can be faster than speed of causality. PBS space time has a good video on this - https://www.youtube.com/watch?v=msVuCEs8Ydo
rhinokungfu··on If the universe is 13.8B years old, how can we see 46B light years away? (2018)
Some of the confusion is, I think from referring to speed of light as "speed of light". When it really is speed limit of causality between 2 points in space. And light (em waves) just happen to be able to hit that limit. Now since expansion of space is itself not going to allow one point in space to cause any effect on another, it (the expansion) can be faster than speed of causality.

PBS space time has a good video on this - https://www.youtube.com/watch?v=msVuCEs8Ydo

rhinokungfu··on Milky Way’s Black Hole Just Flared, Growing 75 Times as Bright for a Few Hours
Speed of light is not really just speed of light, but universal speed limit of causality. Light (electromagnetic waves just happens to be one of the few things capable of hitting that limit. Even the effect of gravity is limited to speed of light. PBS Space time has a good video on this - https://www.youtube.com/watch?v=msVuCEs8Ydo&t=5s.

So to answer your question, no it is not possible for anything to affect us any faster than the universal speed limit of causality (that light happens to be able to hit).

rhinokungfu··on Desktop Metal gets $115M in funding to deliver metal 3D printing
Maybe it is already here... we just call it "life"! Hmmm... maybe that is life is - someone's printer?