2016-03-19 (Saturday)

Today, I learned that:

Once an hour per year, the World Wide Fund for Nature arranges the so-called “Earth Hour”, when they ask everyone on our planet to turn off the non-essential lighting for one hour, during the local time of 20:30 to 21:30, to make us aware of global warming. See reference #1 below for more information.


The Strip in Las Vegas during Earth Hour 2009-03-29

The photos above were taken during the Earth Hour on 2009-03-29 at 21:17 in Las Vegas, Nevada, USA. I was there to visit a trade show during the following week and had arrived in the city on the same afternoon. I managed to obtain a good ticket for the Cirque du Soleil’s performance at the theatre of New York, New York, and when I stumbled out of there, I was greeted by the unusual, almost pitch-black night of the Las Vegas Boulevard (a.k.a. the Strip), so I snapped those pictures in both directions from the overpass in front of New York, New York.

Solution to Problem # 5a, Pizzas, posted on 2016-03-13

So, should you bring one big pizza or two small ones? Do not get confused about the fact that the bigger one has twice the diameter of the smaller one. Since we are comparing two three-dimensional objects, and consider that both types of pizzas have the same thickness, then we must compare the two areas. And since the big pizza has a diagonal that is twice that of the smaller one, then of course the area has the same relation squared. So, the bigger pizza has 4 times the area of the smaller one, yet only costs twice as much. Take the big pizza and go home with twice as much pizza as if you had choosen two small ones. See also the following picture, and “buon appetito” !


Pizza Margherita in two different sizes, the big one has a real diameter of 30 cm and each of the smaller ones have individual diameters of 15 cm

The Margherita pizza was created in 1889 by pizzaiolo Rafaelle Esposito, as a tribute to Queen Margherita di Savoia during her visit to Naples. The ingredients were chosen to mimic the Italian flag: white represented by buffalo mozarela cheese, red by the tomato, and as the green “piece de resistance” fresh basil. In all its simplicity, still one of the best pizzas you can ever eat! See also reference #2 below.

Solution to Question # 5b, Pancakes, posted on 2016-03-13

I also asked why Bill Gates is so fond of pancakes. The answer is that his only scientific article deals exactly with pancakes. This is the story: You are working as an extra hired waiter for the morning rush at the International House of Pancakes. Everyone goes there for their breakfast pancake and today the chef has a bad day. Not all pancakes turn out the same, some are bigger, others are smaller. Your task is to serve the pancakes to the patrons from a neatly arranged pile, with the largest one at the bottom and the smallest one on top. The question is then, is there a maximum limit for the number of times you have to interchange the pancakes until you have reached your objective?

In his article from 1978, Bill Gates at Microsoft in Albuquerque, New Mexico, USA, and his co-writer Christos Papadimitriou developed an algorithm to try and almost answer that question. And their theory was undisputed until 2008, when a team in Dallas, Texas, USA improved it when they applied the pancake flipping theory to a minimization of connections between neighbouring network processors.

… That’s what I learned in school !



2: Pizza Margherita

3: Bounds for Sorting by Prefix Reversal

4: Flipping pancakes with mathematics

5: Team Bests Young Bill Gates With Improved Answer
to So-Called Pancake Problem in Mathematics

+: What did you learn in school today ?

2016-03-13 (Sunday)

Today, I learned that:

Two days ago, 2016-03-11, I was discussing that due to the nuclear accidents that had happened, the safety regulations were tightened in order to reduce the effects of future accidents. However, if certain lessons from Harrisburg 1979 had been taken seriously in Fukushima, maybe their accident would have been causing much less damage than it really did in 2011.

In the same manner, the terrorist attacks on USA on 2001-09-11 led to that the safety measures for access to the cockpit of an aircraft were tightened, so that nobody could enter it without being let in by the occupants of the cockpit. That way, the regulators intended to make it extremely difficult for any trouble makers to take over the aircraft. But what if one of the people in the cockpit was doing something wrong that would jeopardize the flight? This was exactly what happened on 2015-03-24, when the co-pilot of the Germanwings flight from Barcelona to Düsseldorf deliberately crashed his plane into the French Alps. (The header image today shows a photo I took of the Alps from a Lufthansa, parent company to Germanwings, flight the day before Christmas Eve 2001. On the ground level, the ambient temperature was -45 OC, almost the same as on our cruising altitude.)


Germanwings Airbus A320, D-AIPX, which crashed in the French Alps on 2015-03-24

Today was revealed a report about how he, being a bipolar patient, had searched medical treatment with 41 health professionals, but due to the confidentiality obligation, none of them had dared inform the medical department of the airline. However, the rules for the occupancy of the cockpit were once again changed as a consequence of the co-pilots sole action. Now, there is an obligation that there always must be two people in the cockpit.

Still talking about the same Germanwings’ crash, did you know that parts of a football team from the Swedish club Dalkurd was supposed to be in the main cabin of that flight? They were returning home after a training camp in Barcelona, but changed their tickets to a later flight, so that the whole team could travel on the same flight. It saved them their lives! Full news coverage of the crash can be found in references #1 and #2 below.

Problem #5a (Pizza)
It is the evening after a long day and you have promised your wife to bring pizza for dinner. So you stop by at your favourite pizza parlour for take-out. Today’s special is Margherita, the Queen of pizzas, invented in Italy in 1889. They come in two sizes, a round one with 30 cm in diameter and a small one, also round, with 15 cm in diameter. The big one costs € 10 and the small one € 5. You are an economical person, so you have set a limit of spending to exactly € 10, but which type shall you buy, one big pizza or two smaller ones? Does it really matter what you choose? A solution to this problem will be published next Saturday, 2016-03-19.


Question #5b (Pancakes)
And speaking about food, do you know why Microsoft’s founder Bill Gates is so fond of pancakes? I will tell you that as well on Saturday, 2016-03-19.

… That’s what I learned in school !


1: Germanwings Airbus A320 plane crash: Flight 4U9525 down in French Alps with 150 feared dead

2: French investigators to publish report into Germanwings plane crash

+: What did you learn in school today ?