Natalie Keegan with The Sun writes:

It may sound like a minute detail — but the shape of a plane’s windows is actually really important.

In the past, square windows were all the rage and many early plane designs featured them.

However, by the time the 1950s rolled around, the commercial jetliner rose to fame — and this is when problems began to surface ...

The new planes were capable of flying at greater speeds and at higher altitudes than those of the past, but two of them soon fell apart, disintegrating midair — all because of square shaped windows.

This may sound bizarre, but it all comes down to the sharp corners on a square.

The corners are natural weak spots, more likely to be stressed and weakened by air pressure changes and as such are a recipe for disaster when it comes to air travel.

Curved windowpanes, however, have no focal point and distribute stress evenly — reducing the possibility of cracks or breaks.

The Christmas holidays are undisputedly a stressful time, with tensions mounting as we draw nearer and nearer to the day. But just when does all that tension crescendo? At precisely 12:56 pm Christmas Day--this according to a British survey commissioned by Magimix, a premier food processing company.*

Why 12:56? And what is a food processing company's interest in Christmas stress anyway?

Well, it seems our stress comes to a peak at precisely the time most of us are preparing and/or serving our holiday meal. We manage to survive the madness of the malls, the terror of travel and traffic, the festivity fatigue, and the weariness of wrapping, only to be pushed over the edge by the holiday turkey and trimmings.

MailOnline reports:

Almost half of Brits (47 per cent) say preparing the turkey, vegetables, and all the trimmings is the most demanding task they face on December 25.

This is because of the difficulty of timing everything right (33 per cent), and coping with interfering relatives (16 per cent).

Others are stressed by the effort required to chop, peel, baste, and mix (15 per cent), and struggling to squeeze everything in the oven (32 per cent).

The pressure is heaped on by the amount of time put into making sure everything is perfect, found the new study.

The average adult spends four hours 30 minutes preparing and cooking Christmas dinner. …

We first think about the meal on December 14 and then spend 14 hours worrying about it before preparations even start.

A spokesman from Magimix, who commissioned the survey, said: "Christmas cooking is becoming a real source of stress for the nation, with 12.56pm the time we're tipping over the edge."

'It's understandable that people want the most important meal of the year to be perfect but many of us are putting unnecessary pressure on ourselves to impress family and friends."

*While the survey is based on British respondents, the US holiday frenzy is no less frantic.

"Ulcers in Executive Monkeys" was a study into the effects of the stress of responsibility on executives. It was first published in 1958 in Scientific American by Joseph V. Brady.

The study involved giving a test, "executive" monkey the responsibility of avoiding electric shock both for himself and a fellow monkey. First the test monkey was trained to pull a lever at a control panel. Then, at regular intervals, the test monkey was given an electric shock unless he first pulled the lever. Later a "yoked," control monkey was placed in sight of the test monkey. The yoked monkey was likewise shocked at regular intervals unless the test monkey first pulled the lever.

The experiment had to be halted and reformatted because the executive monkey died from perforated stomach ulcers. In all subsequent tests, the responsible, executive monkeys developed ulcers while the yoked, control monkeys did not, leading researchers to conclude that the ulcers were a symptom of the excessive stress induced by the burden of responsibility and control.