Skip to main content

तमिलनाडु में 12 साल से कम उम्र के 121 बच्चे कोरोना पॉजिटिव

चेन्नई में कोरोना वायरस के 103 नए मामले सामने आए. इसके साथ ही यहां पर कोरोना के कुल 673 केस...

from आज तक https://ift.tt/2zye27o

Comments

Post a Comment

Popular Coupons

How next-gen computer generated maps detect partisan gerrymandering

Image
In October 2019, a state court determined that North Carolina’s congressional districts had been severely gerrymandered and struck down the state’s map . The court’s ruling was informed, in part, by tens of thousands of alternative maps demonstrating that the district boundaries had very likely been manipulated for political gain, the very definition of gerrymandering. Researchers had generated a slew of alternative, computer-generated maps designed to help identify potential patterns of bias. The approach is increasingly used, alongside other tests, to ferret out alleged gerrymandering. District manipulations can be so subtle that they’re undetectable just by looking at them. “The eyeball test is no good,” says Jonathan Katz, a political scientist and statistician at Caltech. U.S. states redraw their district lines every 10 years to adjust for changing demographics picked up by the national census. The last round a decade ago raised eyebrows, most notably for districts drawn in Mich...
Read more

Readers ask about positronium, wild bees and more

Image
Dance of the doomed particles Scientists are puzzled by an unexpectedly large gap in the energy levels of an exotic “atom” called positronium, which consists of an electron and a positron, Emily Conover reported in “ Positronium result baffles physicists ” ( SN: 9/12/20, p. 14 ). Reader Lee Skinner asked why the electron and its antimatter counterpart, the positron, don’t just annihilate each other when they collide. Eventually, the electron and positron do annihilate one another, Conover says. As a result, positronium doesn’t stick around forever. “The two particles do a little orbital dance with each other for a period of time before they meet up and annihilate,” she says. “That’s actually part of how the researchers made the measurement, though I didn’t have the space to include those details in the story.” The team measured how long it took electrons and positrons to annihilate, which depends on the atoms’ energy level. “Timing that annihilation revealed whether the positr...
Read more