Thursday, 8 June 2017

Angles, Stars, Owls

Langley's Adventitious Angles

I came across this puzzle a couple of days ago. It's incredibly hard yet it only needs a bit of basic geometry to solve. The trick to solving it is rather clever and I enjoyed it tremendously.

Missing Star

A star has disappeared! It was imaged by Hubble, but now it's not there any more. There was no supernova, so maybe this means that a massive star can turn into a blackhole without turning supernova first. More information can be found at the Astronomy image of the day for a couple of days ago.

Owls and Lemmings

Snowy owls feed on lemmings. Lemmings have good years every 4 years. In one of these good years, a snowy owl built its nest from 70 dead lemmings!

Tuesday, 6 June 2017

Hand Washing, Polio

Hand Washing

I score for cricket and sometimes the grounds don't have hot water in the wash basins, or maybe no soap. Does this matter? Sometimes there are no towels and no hand drier, so is it ok to not dry your hands?

If you used water hot enough to kill bacteria such as salmonella, you would scald your hands in just 30 seconds whereas the bacteria would survive more than 10 minutes, so you can't get the water hot enough to matter. I also can't imagine anyone standing there washing their hands for 10 minutes even if the water wasn't too hot! What matters is soap, rather than the temperature of the water. Anti-bacterial hand-washes are no better than soap, and can give rise to resistant bacteria.

As for drying your hands, it's ok not to if you aren't going to touch anything until they are dry which can be a bit difficult when you have to open the door to get out! If your hands are wet and you do touch something, the bacteria will have an easier time transferring to your hands than if you hands had been dry.

For more information see the BBC article Does it matter how you wash and dry your hands?


I've written about polio before on my other blog as we're so tantalisingly close to wiping it out completely. According to the NHS on polio, 95% of people who get polio don't even know they've had it, but 0.5% get permanent paralysis, which can be life-threatening. Because so few get symptoms, the WHO considers one confirmed case of polio paralysis to be evidence an epidemic. 5-10% of those who are paralysed die. Of those who survive, 40% get post polio syndrome 15–40 years after they first got polio. The symptoms of this include progressive muscle weakness, severe fatigue, and muscle and joint pain.

There are three types of wild polio virus. The last case of type II was in 1999, and in 2015 it was declared eradicated; the last case of type III was in September 2012. Type I is still indigenous in three countries: Afghanistan, Nigeria and Pakistan. The are also occasional cases of vaccine derived polio outbreaks. This is when the live weakened virus in the oral vaccine mutates and causes polio in an under-vaccinated population. However, the vaccine derived outbreaks don't seem to be easier to contain than the wild ones.

For up-to-date information, see the Polio Global Eradication Initiative site which is updated weekly.

Sunday, 4 June 2017

Commas, Aluminium Pots

Using Commas to Change Meaning

In some cases, I was aware of commas changing meanings. "Panda eats, shoots and leaves" has a very different meaning from "Panda eats shoots and leaves." However, there are cases where I was not conscious of there being a difference. In the sentence "I fed the dogs which looked hungry" I picked out the hungry dogs and fed them whereas in the sentence "I fed the dogs, which looked hungry" I feed all the dogs and they happened to look hungry.

Using Aluminium Pots

When dyeing, using an aluminium pot can cause unexpected results as there is always some aluminium dissolved in the liquid in an equilibrium with the solid pot. Aluminium salts are mordants.

Saturday, 3 June 2017

Tattoos, Chimera, Toff's Error

Just a few odds and ends today.


Don't swim in open water for two weeks after having a tattoo as it could kill you! Since tattooing breaks the skin, there is a chance of infection. This has led to ,a href="">death in a man who swam in the Gulf of Mexico a five days after getting a tattoo.


A chimera is caused by embryos merging in the first 24-48 hours after conception. One embryo could be male and the other female making an xx/xy person.

The Toff's Error

Using 'I' instead of 'me' such as in "They invited the wife and I" is incorrect and is called the Toff's error as some people who do it think it sounds posh. (Source: My Grammar and I (or should that be 'Me'?) by Caroline Taggart and J. A. Wines)

Friday, 2 June 2017

Hammerum Girl's Dress, Pointing and Calling

Hammerum Girl's Dress

In 1993, some late Roman Iron Age (AD 200-400 AD) graves were discovered. In one of them, there were textiles. The video below shows how the dress of the so called Hammerum Girl was created and would have looked. It includes shearing the sheep, making a spindle, spinning the yarn, making the loom weights, setting up the loom, weaving the fabric, card weaving the trim, sewing the dress up, and finally how to wear it.

Japanese Pointing and Calling

In order to cut down mistakes, a practice in Japan is to point and call when doing a task. Instead of just looking at a dial to check it, say speed, you point at it and say the speed. If you are checking a train track for obstacles, you point up and down the track and follow the pointing with your eyes. This technique had cut down errors by 85%. It seems crazy that this is not done elsewhere, but apparently people are too embarrassed. It's tragic that embarrassment is more important that reducing mistakes and improving safety.

Thursday, 1 June 2017

GMOs, Owls, Cockroaches


GMOs have the potential to save lives, such as with golden rice, enriched with vitamins. Another way in which GMOs can change lives, and even protect the environment is through pest-resistant crops. Here's a video on how farmers in Bangladesh are finding growing GMO aubergines. They use 80% less insecticide (which must be good for the eco-system) and get higher yields.

Tawny Owls

Tawny owls hunt at night so they need to be able to see. Their eyes are about 2.5 times more sensitive in low light than our eyes, and take up 70% of their skull compared with just 5% for ours. (Source: BBC TV Springwatch)

Madagascan Hissing Cockroaches

We know that most mammals give birth to live young and birds lay eggs, but is there something in between?

The Madagascan hissing cockroach – they're huge and kind of cool for a cockroach, but I digress – lays eggs which is covers in a hard case before retracting them back into its body. The eggs develop within this casing and when they're ready to hatch, the casing is pushed out of the body again and the fully developed cockroaches hatch. It's an evolutionary stage between egg laying and live birth with a placenta and is called ovoviviparity.

egg-laying such as birds, some snakes
producing living young which develop within the body such as humans, some snakes, Madagsacan Hissing Coackroach
This is a subdivision of the viviparous reproductive strategy, where live offspring which hatch from eggs within the body of the parent. This offspring are nourished from an egg yolk rather than from the parent directly. The Madagascan hissing cockroaches mentioned above are one example, and another is the slow worm.

Wednesday, 31 May 2017

Cleaning Fleeces

One of the things I'm interested in is traditional crafts so learning about how fleeces can be cleaned is something that peaked my interest. A method for cleaning several fleeces is called the Fermented suint method. It involved soaking a fleece for a week in rain water. The sheep's sweat (suint) and lanolin form a sort of soap which cleans the fleece as it soaks. The resulting liquid is then used to clean further fleeces which don't need as long as the liquid becomes more effective the more fleeces are cleaned in it.

Mary, Queen of Scots

I've always been terribly confused about Mary Tudor and Mary, Queen of Scots. Finally I have it straight and understand how the family tree fits together.

Henry VII had eight children of whom only three survived to adulthood.

  1. Margaret (1489-1541) married James IV, King of Scotland becoming Queen of Scotland, then Archibald Douglas and finally Henry Stewart,
  2. Henry (1491-1547) became King Henry VIII,
  3. Mary (1496-1533), became Queen of France.

Margaret had four children by James VI of Scotland, one of whom was James V of Scotland. She also had a daughter, Margaret Douglas by Archibald Douglas, and finally a daughter by Henry Stewart.

King James V of Scotland had a daughter, Mary who became Queen of Scots. This means the lineage was: Henry VII -> Margaret -> James V of Scotland -> Mary, Queen of Scots, making her the great granddaughter of Henry VII.

Mary Tudor was the daughter of Henry VIII, and thus the granddaughter of Henry VII. This means that Mary, Queen of Scots was the first cousin once removed of Mary Tudor.