21 ms·
Exponential Growth and Covid-19 [video]
- nabla9 7y agoIn simplest possible SIR model that takes into account the growing recovered and immune, (1 − 1/R0) of the population gets infected. R0 is the reproduction rate. R0 | % of population ---------------- 2.5 60% 2.0 50% 1.5 30% The effective reproduction rate decreases when people take precautions. There is no reason to assume it's constant or same in different countries and cultures.
- geggam 7y agoIn countries where sanitation is an issue will the infection rate ever slow and when people from countries who have it controlled travel to those countries does it restart ? I think I have more questions now that I watched the video than I do answers :)
- ajuc 7y agoCountries with worse sanitation also tend to have slower transportation and less population shuffling. In the times of plague the places that suffered the least were: - sparsely populated - didn't participated much in the international trade - used quarantines on the borders early https://bigthink.com/strange-maps/bubonic-plague-spares-poland?rebelltitem=3#rebelltitem3 https://bigthink.com/strange-maps/bubonic-plague-spares-pola...
- jacobolus 7y agoIn modern times there is plenty of transportation and shuffling in crowded countries with poor sanitation. Remember it only takes a tiny bit of travel to spread a virus far and wide. I would predict things will get very bad in many parts of Latin America, Africa, and South and Southeast Asia.
- ajuc 7y agoThere's a big difference between average daily commute being 5 km and 50 km.
- microcolonel 7y ago> The effective reproduction rate decreases when people take precautions. In looking at the outbreak gripping Italy, it seems like hard quarantine is the most basic precaution, and perhaps we should be taking it before the first hundreds of people die in each of our countries.
- TrumpMyGuns 7y agoMost people are reactive and view proactivity as stupid, a waste of time, etc. I'm sure many people have dealt with this while writing software. tl;dr: People are idiots.
- vanniv 7y agoItaly's quarantine will probably kill many more people than the virus ever could
- microcolonel 7y agoWhat's your reasoning on that? I really want to know, since on the face it seems like an absolutely outrageous, borderline random conclusion to draw.
- vanniv 7y agoIt has been 2 days. Now, all businesses except grocers are closed, and grocers are mostly out of food. Roads are closed. People are going to be very, very hungry very, very soon. Hunger will create desperation, which will create violence, which will quickly dwarf the few thousands of people that covid will kill
- melling 7y agoChina looks like its growth has flatlined, while the rest of the world is moving along an exponential curve. https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594... Also, notice that 57k out of 81k have recovered.
- microcolonel 7y ago> Also, notice that 57k out of 81k have recovered. But also, at least 3,097 people out of the 80,699 have already died, and by the same measure, 20,283 of the confirmed have yet to recover.
- d0mine 7y agoThe death ratio should only increase as the medical resources are exhausted
- melling 7y agoIf the curve has flatlined in China and only 20,283 remain, China should not have a further problem with resources. The rest of the world, of course, is just getting started.
- geggam 7y agoWhat happens when infected soul from US / other place visits china ? Is there an immunity built up in infected people or does the clock reset ? You cant quarantine the world and expect a global economy to survive
- DailyHN 7y agoGotta love the people that see people dying and are most concerned about the economy.
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- lhl 7y agoI've been tracking the coronavirus news for the past few weeks and have found https://www.reddit.com/r/covid19 https://www.reddit.com/r/covid19 to be good for tracking the latest scientific/medical publications, and https://www.reddit.com/r/coronavirus https://www.reddit.com/r/coronavirus for general news. For transmission rates, this team is updating their modeling results often: https://cmmid.github.io/topics/covid19/current-patterns-transmission/global-time-varying-transmission.html https://cmmid.github.io/topics/covid19/current-patterns-tran... On twitter, @datagraver is publishing some of the most interesting visualization/graphs: https://twitter.com/Datagraver https://twitter.com/Datagraver I've found this via mrb (@zorinaq) who's been tracking the covid19 spread: https://twitter.com/zorinaq/status/1235850389020270595 https://twitter.com/zorinaq/status/1235850389020270595
- haunter 7y agoBoth of those subs are incredibly tinfoily and panicky. Honestly reddit is the worst. And BI is right that they are doing the same as always, just consiparcy things https://www.businessinsider.com/coronavirus-reddit-social-platforms-spread-misinformation-who-cdc-2020-3 https://www.businessinsider.com/coronavirus-reddit-social-pl... Also you might as well rename /r/Coronavirus/ to /r/politics2 aka fucktrump. It's the same thing over and over again
- DuskStar 7y ago/r/Coronavirus used to have some info on it. But yeah, for the past week+ (since Reddit began linking it on the front page, maybe?) every other article has been "the US isn't testing enough", and the comments of every article have degenerated into "Trump is literally evil, this is all being done for the benefit of corporations, he just wants to protect the stock market" which is really not helpful. It might (or might not) be accurate, but that's kinda irrelevant.
- tic_tac 7y agoAgreed, Reddit is cancer. Reactionary hive mind internet at its worst. One of the biggest problems with Reddit is that Americans go on boards like /r/politics or in this case /r/Coronavirus, see extreme hostility towards America and Trump and assume that this hostility is all coming from Americans themselves, when really a substantial number of Reddit users (and users elsewhere on the Internet) are not American. Not being Americans, their hostility comes more from predisposed bias against Trump and America than a careful analysis of what's best for America.
- melling 7y agoThe video says that it's really a logistic curve. Which is also the activation function (sigmoid) in a few machine learning articles that I've been reading. https://en.wikipedia.org/wiki/Sigmoid_function https://en.wikipedia.org/wiki/Sigmoid_function https://en.wikipedia.org/wiki/Logistic_function https://en.wikipedia.org/wiki/Logistic_function Can anyone recommend anything to read to add more clarity? Why does this appear in deep learning too?
- andrewprock 7y agoIt's used in algorithms to provide a continuously differentiable function, which is much easier analyze than a step function.
- fsh 7y agoFor neural networks to work, the activation function has to be nonlinear and monotonic. In order to be able to apply the chain rule for training the weights by backpropagation, the function also has to be differentiable. The logistic function is one obvious choice, but other functions such as tanh, arctan or relu are popular as well.
- bno1 7y agoIn machine learning it's used as an activation function. Activation functions are used to add non-linearity to the model. I think sigmoid functions are inspired from neurons, but I'm not sure exactly how. Nowadays, ReLU activations are used more often than sigmoidals because they are quicker to compute.
- bno1 7y ago>I think sigmoid functions are inspired from neurons I mean the use of sigmoids as activations in NNs
- cmarschner 7y agoReLu are mainly used because in practice they show better results than sigmoids in many areas. The fact that they are also faster to compute is just a nice side effect.
- ccarpenterg 7y agoWhat about Polynomial growth: https://oeis.org/wiki/Growth_of_sequences#Polynomial https://oeis.org/wiki/Growth_of_sequences#Polynomial
- yters 7y agoSeems to have a much lower hospitalized mortality rate than 2017 flu https://www.google.com/amp/s/www.livescience.com/amp/new-coronavirus-compare-with-flu.html https://www.google.com/amp/s/www.livescience.com/amp/new-cor...
- shawabawa3 7y agoFrom (probably slightly misremembered) stats I've seen, it has approximately 40x the hospitalisation rate, but only 10x the death rate of flu So yes, lower hospitalised mortality rate but only because so many more people are hospitalised
- yters 7y agoDo we have an accurate count of cases? For example if most cases are determined based on hospitalization, then the hospitalized death rate is the same as the estimated actual death rate. I haven't been able to find studies on the hospitalization rate to know.
- deleted 7y ago[deleted]
- empath75 7y agoNot a useful statistic without knowing the hospitalization rates.
- cklaus 7y agoAmerican Hospital Association "Best Guess Epidemiology" for #codiv19 over next 2 months: 96,000,000 infections 4,800,000 hospitalizations 1,900,000 ICU admissions 480,000 deaths vs flu in 2019: 35,500,000 infections 490,600 hospitalizations 49,000 ICU admissions 34,200 deaths
- abootstrapper 7y agoSource link?
- CharlesW 7y agohttps://www.businessinsider.com/presentation-us-hospitals-preparing-for-millions-of-hospitalizations-2020-3 https://www.businessinsider.com/presentation-us-hospitals-pr...
- cklaus 7y agoSource: https://www.businessinsider.com/presentation-us-hospitals-preparing-for-millions-of-hospitalizations-2020-3 https://www.businessinsider.com/presentation-us-hospitals-pr...
- nabla9 7y agoWhere it says next 2 months? If the doubling time is one week there is just something like 100k - 200k infections in next two months. I think those numbers are yearly infection estimates.
- graeme 7y agoI think the graph meant 96 million infections active in the peak two months. Hard to be sure without seeing the presentation, but it definitely isn’t the next two months.
- nateberkopec 7y ago"The American Hospital Association said the webinar reflects the views of the experts who spoke on it, not its own." You're quoting the opinion of one person: Dr James Lawler, a professor at the University of Nebraska Medical Centre. That person researches infectious diseases, so, their opinion isn't a complete guess of course, but we should ascribe the numbers to the right source.
- tic_tac 7y agoThere are two extreme paths we can take. The first is that we do nothing, the other is that we completely lock down our society like China. While the first option would be unwise, the second would also be unwise. A complete shutdown for a disease as virulent as Covid-19 will just suppress the virus for the duration of the shutdown. Ignoring the extreme difficulty and impracticality of shutting society down for a moment, recognize that the moment the shutdown ends, the virus will probably reappear and continue to spread. What then? Another complete shutdown? When does it end? No, the right solution is a distributed solution in which affected companies and communities deal with the virus, imposing gradual restrictions on gatherings, work, schooling etc in an organic way. Which is exactly what is happening in the US right now. The point of all this is, what more can the US government do than it is already doing? Send the military in to shut down the highways? Hold scientists at gunpoint until they produce a vaccine? Many (Media, Democrats) are trying to leverage this to their political advantage, but aside from small changes in approach, what exactly do they want the government to do differently?
- DuskStar 7y agoNot limit testing? Approve the use of private testing facilities? Allow automated testing? Those would all be good steps.
- Florin_Andrei 7y ago> Many (Media, Democrats) are trying to leverage this to their political advantage lol, found the echo chamber repeater
- qqqwerty 7y ago> Many (Media, Democrats) are trying to leverage this to their political advantage To date, most of the complaints about the current administrations' handling of COVID-19 have been about the cuts to the CDC, the history of Pence and Redfield regarding HIV, and other fact based arguments and criticisms. It is entirely possible that none of these factors had or will have a substantive impact on the spread of COVID-19. But they are still valid criticisms none the less. In contrast, take Trump's response to the Ebola crisis[1], which was a remarkable example of fear-mongering and politiking in the face of a potential crisis. [1]https://www.vox.com/2020/2/26/21154253/trump-ebola-tweets-coronavirus https://www.vox.com/2020/2/26/21154253/trump-ebola-tweets-co...
- FranceBacce 7y agoIf anyone wants to dig into the math, this is a non linear recurrence relation, with an external dependency, that is n_d+1 = f(a,n_d) n^(d+1) bad news: How this behaves will depend a lot on a (containment measures etc...) good news: If we can make a grow faster than an exponential, we can win
- sgt101 7y agoDoes anyone have numbers for testing? I'd like to know how many tests are being done in each territory?
- tunesmith 7y agoI figure there's some kind of "true" fatality rate that just answers the question of "If you catch the virus, you have this (age-adjusted) chance of dying". It seems like we'll asymptotically reach that "true" rate once testing is extremely common and liberal (to have confidence you are identifying all cases). Some countries are reaching that testing rate. Then your upper and lower bounds for that death rate are "deaths / deaths + recoveries" and "deaths / confirmed cases", respectively, and they should converge as "active cases" decrease over time (as they either recover or die). You can use that "band" (between the upper and lower bounds) to judge other countries and determine whether they are testing enough - if they are above that "band", they are clearly not testing enough.
- swsieber 7y agoAre we talking with or without ventilator/hospital support?
- tunesmith 7y agoYeah, that's a good point. Fatality increases as treatment options decrease. Treatment options can decrease whether it's a less advanced country, or a more advanced country that just gets overwhelmed due to poorer containment than other advanced countries.
- MaysonL 7y agoThe thing is, there are probably some people who won't die, no matter how they're treated, and some who will die, no matter how they're treated. There are also quite a large number, probably about 4-5% of the population, who can be saved with correct treatment, from not very aggressive to extremely aggressive - up to running the blood through artificial lungs.
- m463 7y agoA friend mentioned to me that smokers seem to be more likely to succumb, probably because of the effect on lungs.
- JetBen 7y agoAs an anxious person, I actually found it calming to watch the math of it all.
- XiZhao 7y agoVCs love this virus!
- forkexec 7y agoSigh. It's not exponential growth, it's best modeled by a differential equation. Like population, the rate of growth is proportional to the amount present up to the current carrying capacity (that varies widely in the real world and with time).
- CPUstring 7y agoThat is explained in the video