L2: kool
Kellad kivimis
BIOÜks eksponentfunktsioon, loetav kolmel viisil. Otsesuunas näitab see allesjäänud kogust; pöördsuunas reedab millegi vanuse. Ja aatomituumade asemel DNA-le rakendatuna vajab see kivimit, mille järgi end õigeks seada.
Interaktiivsed matemaatika- ja teadusõppetunnid (ノ◕ヮ◕)ノ*:・゚✧
Bioloogia näib erandite teadusena seni, kuni hakkad lugema. Doos, pärilikkus, populatsioon ja reaktsioonikiirus järgivad reegleid, mis on piisavalt ranged, et ennustada, ja just seda need tööriistad teevad.
Kaardiprojektsiooni moonutuse labor
Lohista laiuskraadi ja võrdle Mercatori ning õigepindse kaardi kompromissi.
Piirav reagent ja stöhhiomeetria
Leia piirav reagent, teoreetiline saagis, ülejääk ja protsendiline saagis.
Lühikesed jadad üksikute tööriistade asemel. Iga samm annab järgmisele midagi kindlat, seega tasub need läbida järjekorras.
L2: kool
BIOÜks eksponentfunktsioon, loetav kolmel viisil. Otsesuunas näitab see allesjäänud kogust; pöördsuunas reedab millegi vanuse. Ja aatomituumade asemel DNA-le rakendatuna vajab see kivimit, mille järgi end õigeks seada.
L2: kool
STATBayesi teoreemi aritmeetikale ei vaidle keegi vastu. Vastu vaieldakse aprioorsele tõenäosusele: kust see esimene arv pärineb ja kes selle valis. Need kolm vahendit käsitlevad seda küsimust raskusastme järjekorras: aprioorne tõenäosus, mille saab järele vaadata, mille annab seade, ning aprioorne tõenäosus, mida pole kellelgi.
L2: kool
BIOIga siinset populatsiooni hoiab miski tagasi. Iga sammuga muutub see miski üha järeleandmatumaks: esmalt populatsiooni enese tekitatud ruumipuudus, seejärel püsiv väljapüük, siis kiskja, kes on ka ise omaette populatsioon, ja viimaks saavad otsa inimesed, keda nakatada.
L4: eriala
BIOViis vahendit, mis moodustavad ühe argumendi: DNA on reaalne andmekandja ja tõeline arvuti ning mõlemad jõuavad piirideni, mida saab oletamise asemel välja arvutada. Iga samm annab järgmisele edasi konkreetse arvu.
The 475-year earthquake is not geology
Two odd numbers are stamped on seismic design maps worldwide. Neither was measured. Both are a tolerated failure probability run through one line of algebra — and the same line explains why a 100-year flood is a coin-flip over a lifetime.
Thirty-nine cities need more DNA than the Earth
DNA computing promised to beat exponential search with molecular parallelism. The counting that kills it is the argument Levinthal used to prove that proteins cannot be searching for their shape — and what survives the argument is not speed at all.
Kill both species at the same rate and you get more of the pest
The predator–prey model has an exact long-run average, and it sits in a strange place: raise the death rate of both species equally and the average prey population goes up. Volterra found it in fish-market ledgers in 1926.
Below one it dies out. Above one it runs away. There is nothing in between.
The same threshold governs epidemics, nuclear chain reactions, PCR and surnames: if each unit produces on average fewer than one successor, extinction is certain. The knife edge is exactly at 1, and the mathematics was first worked out on Victorian family names.
The herd immunity threshold is 66.7%, so why does the epidemic infect 94.1%?
The threshold is where an outbreak stops growing, which is nowhere near where it stops. It keeps infecting people well past that point, and the size of that overshoot is the argument for arriving at the threshold by vaccination rather than by illness.
Fifty generations of perfect selection halves a recessive gene, and that is the best case
Suppose a recessive condition were lethal in every case, in every generation, with no exceptions. After fifty generations the allele has gone from 2% to 1%. The arithmetic explaining why was published in 1908.
A radioactive atom does not know how old it is
An atom that has already survived a million years is exactly as likely to decay in the next second as one created moments ago. Exponential decay is the only continuous law with that property, and it is why half-life is a meaningful number at all.
A magnitude 7 is not slightly worse than a magnitude 6
It releases about 32 times the energy. Logarithmic scales compress catastrophes into numbers that look adjacent, which is exactly the problem with reporting them.