Thursday, November 24, 2016
In probability theory, the birthday problem or birthday paradox concerns the probability that, in a set of n randomly chosen people, some pair of them will have the same birthday. By the pigeonhole principle, the probability reaches 100% when the number of people reaches 367 (since there are only 366 possible birthdays, including February 29).
However, 99.9% probability is reached with just 70 people, and 50% probability with 23 people. These conclusions are based on the assumption that each day of the year (except February 29) is equally probable for a birthday.
Wednesday, November 16, 2016
Each lung is divided into upper and lower lobes. The right lung is larger and heavier than the left lung, which is somewhat smaller in size because of the position of the heart. The upper lobe of the right lung contains another triangular subdivision known as the middle lobe.
The heart is asymmetrical and is more on the left side of the body than on the right. Thus it follows that the left lung is smaller because there’s a heart in the way.
Wednesday, November 2, 2016
In 1999, two mathematicians, Thomas Yink and Yong Mao, examined the actions involved in tying a necktie and calculated that there were 85 different ways to do so.However, a new team of mathematicians has trumped their research. Mikael Vejdemo-Johansson of the KTH Royal Institute of Technology in Stockholm and a small team of mathematicians found that Fink and Mao had left out some possibilities.
"We extend the existing enumeration of neck tie knots to include tie knots with a textured front, tied with the narrow end of a tie," Vejdemo-Johansson wrote in the abstract of the team's paper, "More ties than we thought".
"These tie knots have gained popularity in recent years, based on reconstructions of a costume detail from The Matrix Reloaded, and are explicitly ruled out in the enumeration by Fink and Mao (2000)."
With this discovery, the team realised that something wasn't quite right, so they had a look at Fink and Mao's research. They realised that Fink and Mao had restricted the number of tucks that occur at the end of knotting the tie to just one. They had also made the assumption that any knotwork would be covered by a flat section of fabric, and restricted the number of windings to just eight.
Armed with this information, Vejdemo-Johansson's team adjusted the parameters of Fink and Mao's language and calculated that the number of possible knots is much, much higher than the previous calculations: 177,147, to be precise.
Tuesday, November 1, 2016
“They feed in the air, they mate in the air, they get nest material in the air,” says Susanne Åkesson from Lund University in Sweden. “They can land on nest boxes, branches, or houses, but they can’t really land on the ground.” That's because their wings are too long and their legs are too short to take off from a flat surface. Hence the fittingly-named birds' species name, Apus, which translates to "footless". It's actually safer for them to be up in the air than on the ground.